The Glass Menagerie Essay Example | Topics and Well Written Essays - 500 words

The Glass Menagerie - Essay Example She would rattle off the numerous names of her suitors and she would recount their consequent fame and fortune after some years. However, she would always refer to her husband with a note of regret and sadness. Amanda also failed to accept the disability of her daughter, Laura, who is a cripple, so she refused to face the reality that Laura would naturally have fewer suitors due to this disability. Instead, she would say that there must be a typhoon on a certain day since Laura has no gentleman callers. Amanda also exercises considerable control over her children. For instance, Amanda demands that Tom, her son should join them during meals. One of her dreams is that Laura gets to marry a fine gentleman. She also wants Laura to study the typewriter and practice the shorthand so that the gentlemen callers will perceive that she is well-bred. Laura has a low self-esteem as shown by her deep sensitivity to the negative perceptions of other people. She also seems to have an unstable mental condition. Instead of braving the negative perceptions of her classmates at the Business College, she instead chose to stay at home and be comforted by the presence of her glass collection. Hence, she settled for a less daunting feat: playing with beautiful glass figurines everyday.

Educating Rita by Willy Russell Essay Example for Free

Educating Rita by Willy Russell Essay Rita, Frank and their relationship change throughout the play. Ritas education and confidence both grow as the story progresses. Franks attitude towards life declines dramatically en route for the middle of the play but there is hint of improvement at the end. Their relationship undergoes many changes during the play. They grow apart, slowly and eventually reach a point where their separation is much needed and inevitable, although their feelings towards each other are of affection once again. At the beginning of the play Rita is a stereotypical working class girl, with little education and a lot of determination. She uses a lot of slang and colloquial language, stupid bleedin handle and off me cake, which shows her lack of education and her class. Rita appears ro be a confident girl, but she uses humour to cover up her nerves, thats what I do. Y know when Im nervous. Rita is also a lively, talkative person and very blunt and forthright. She shows this when she takes the pencil from Frank and scribbles out the letter S. Rita has a particularly determined character. At the start of the play she knows that she wants an improved life, with choices and she knows an education will give her that. So she is making sure she is going to get it, even at the cost of her marriage. When Rita leaves Denny she still wants to learn and discuss her Macbeth essay immediately. At the beginning of Act 2 Scene 2 Rita is seen oiling Franks door. This shows her determination and that she follows through her word, does what she says she will. Russell uses stage directions to show Ritas energy, the door bursts open and Rita flies in. The words flies and burst convey bubbly, lively movements and therefore her energetic character. At the start of this play Frank is a stereotypical upper-middle-class man. He is apathetic sarcastic and relatively independent. Frank uses Standard English and Received Pronunciation, showing his high class and good  education. He asks pardon? instead of what? and explains that the Open University is supposed to embrace a more comprehensive studentship. Frank is not dependant on anyone, but he drinks a lot and I think that he relies on alcohol a great deal. Therefore I would not say he is totally independent. Frank is very sarcastic and quick witted. He uses his sarcasm as a defence mechanism, or to make a point. He doesnt use it nastily or to hurt anyone. I sometimes get an urge to throw something through ita student usually. This shows him using sarcasm for humour but it also shows his disinterested, lazy attitude to life. Frank is bored of his life but, unlike Rita, he cannot be bothered to change it. He finds himself dull and tells Rita that she is the first breath of air thats been in this room for years. He does not want Rita as a student as he sees her as a lot of work, this shows his lazy attitude. However, the audience could also see this as a selfless and considerate moment. He does not want to take Rita on as a student as he does not think he is capable of teaching her. Frank is extremely clever and refers to high culture, such as T.S Elliot and Yeats, showing his high education and understanding. At the start of the play Frank is bored, funny, sarcastic, clever and shrewd. Frank and Rita get to know each other well and are very close, at the beginning of the play. They flirt and compliment each other, he doesnt half get on my tits/Frank: Good. Youll have to show me some evidence/Rita: Y dirty sod. And Right now theres a thousand things Id rather do than teach, most of them with you my dear. They trust one another and show this through discussion of their personal issues, I live with a girl. Ex-student. Shes very caring, very tolerant, admires me tremendously and spends a great deal of time putting her head in the oven. They then go on to discuss Julia and Franks relationship. Their ability to talk freely to each other shows that they are at ease in each  others company, relaxed and confident around one another. Nevertheless, their relationship is not always easy. It is hampered by their different frames of reference. At one point Frank thinks Rita is joking about T.S Elliot the poet, when in fact she is referring to Elliot Ness, y know, the famous Chicago copper who caught Al Capone. At another point Rita is calling Frank a Flora man from the advert for the butter: flora. Frank assumes she means flora as in flowers. However, Frank and Rita have a mutual understanding of each other, which helps them work through and get beyond their misunderstandings. Their differences intrigue and fascinate one another. This helps keep their relationship alive and fresh. In the middle of the play we see dramatic changes in Rita. Right at the beginning of Act 2 Russell indicates a change by Rita entering wearing new second hand clothes. Rita is at a very difficult point in her change. She has come so far and cannot go back to where she used to be, but she is finding it difficult to carry on, she is half way and stuck in between two worlds. Rita chooses to persevere. Rita has much more confidence and is using humour to hide behind less. She is more educated and has been influenced by lots of people over the summer. Her confidence shows when she tells Frank about summer school. She explains how she asked a question even though everyone was looking at her and two thousand people had seen me stand up. She then goes on to say, after that I was askin questions all week. Before summer school Rita wouldnt have dared do something like that. As well as her confidence improving she is now using more Standard English, although still using colloquial language. Summer has had some less positive effects on Rita, too. She has been very influenced by Trish and although she has now got a better understanding of literature she still does not have her own views. She has merely swapped Franks opinions for Trishs opinions. Frank comes back from holiday even more fed-up with life than before. Rita asks him what France was like, marvelling at the opportunity to go abroad. Frank gives an uninterested answer of well it was rather hot. He is very dismissive, taking for granted the occasion of going abroad and his answer is slightly hostile and cold. He seems to be more apathetic and very low, not recognising that he has got so much going for him. it is indeed because I have got so much going for me that I do itI need the drink to help me step delicately through life. This comment shows that he is still using sarcasm, it shows his sad view on his life and he tells us that he needs drink. This informs us that he has become very reliant on drink. He is worse than he was before, turning up to lectures drunk and not taking anything seriously. He does not even bother to hide the drink anymore. He carries it, in his briefcase, to lectures. The briefcase symbolises work, so to carry alcohol in it shows just how little he cares. Frank now chooses to ignore his education; Rubyfruit Jungle is excellent. He is reverting to how Rita was. Whereas, Rita now has a view, shows her understanding and expresses it formally. They have echoed each other. Franks language has also changed. He is reiterating phrases from Rita, completely off me cake, and he has picked up some of her slang. He is still sarcastic, but sometimes in a hostile, jeering way, like when he shouts names at Rita Charlotte? Or Jane? Or Emily? At the mid-point in the play Frank is hopeless, he challenges Rita saying and well all live happily ever after? Saying this squashes dreams, is sarcastic and apathetic and takes a completely pessimistic outlook on life,  his decline is continuous. Their relationship dwindles when they meet again after summer. The changes in Rita have a big role to play in the downward spiral of their relationship. Rita is becoming more independent, She needs Frank less, he begrudges her this and it causes tension. Dont y like me now that the little girls grown up, now that y can no longer bounce me on daddys knee an watch me stare back in wide eyed wonder at everything he has to say? They understand each other less and know little about each others lives. It struck me there was a time you told me everything, Frank is wistful and shows a sense of longing. He feels Rita slipping away, I cant bear you anymore, he tells her, you dont have to put in a visit out of sentimentality. They no longer have a close relationship and Frank misses and feels bitter about that. They become increasingly resentful towards each other. Frank start to get jealous and resentful of Trish, this feeling fuels further conflict. Will you kindly tell Trish that I am not giving a tutorial to a Dalek. This remark shows coldness in their relationship, the warmth, flirting and friendly banter has gone. At the end of the play Rita has more choices than before, she is educated, confident and able to think for herself. Rita is undecided what the next step in her life should be, but she now has a choice and this is what she set out for: to be able to choose. I might go to France. I might go to my mothers. I might even have a baby. I dunno. Ill make a decision, Ill choose. I dunno. She is educated now and has passed her exam. Arguably more important is that she is no wise. She can think for herself, think logically and develop her own opinions. You woulda loved it if Id written Frank knows all the answers across me paper, wouldnt y? However, Rita did not and this shows  her education and thinking skills. She uses Standard English more now, such as scholarly neckline. Again showing her education. Rita is no longer hiding behind humour, but she is genuinely confident and still funny. Probably the biggest change in Rita from beginning to end is that she now understands Franks views and realises he was and is on her side. She places a Christmas card with the others already there. The card is a token of friendship and signifies her realisation that what she had was not all that valuable. Her realisation shows how she has matured, changed her way of thinking and now feels more kindly for Frank. Frank is now sober and hints that he will make a change in his life. There is now some optimism. He is trying to think well of his move to Australia, things are just beginning there this implies he will take this as an opportunity to start fresh, itd be good for us to leave a place thats just finishing for one thats just beginning. Frank accepts the changes in Rita and shows his thoughtful side when he gives her the dress. He also has a realistic moment and says, I was rather pissed when I bought it. He is not pretending to be a reformed character and he is reminding the audience of his drinking and old habits. Frank is now using Standard English again, metaphorically. And as it was metaphorically the sentence was reduced from the sack to two years in Australia. He is still humorous, Forsters lager they call it, and is sarcasm is still there, but it is no longer hostile. Although Frank is in a worse position than at the start of the play there is hint of improvement and a better life. Ritas response to Trishs suicide and Franks realisation of the need to change has resulted in a greater mutual understanding and a friendlier relationship. I knew how much it had come to mean to you. Frank did not like Rita in the middle of the play but understands why she was like that. They both accept the changes in each other. Rita now appreciates all the help Frank gave her, I came to tell you youre a good teacher. Frank realises her learnt a lot from Rita, too, all Ive ever done is taken from you. Ive never given anything/Frank: thats not true. Youve They understand that they have got to go their separate ways now, and move their lives on, but they part on good terms. Rita begins as a stereotypical working-class girl, with a poor education, who hid behind humour. She goes through a series of changes and ends the play as a confident, wise, educated young lady, ready to make her own choices and get on with her life. Frank begin as a upper-middle-class man, he was very sarcastic, had a poor attitude towards life and relied on drink. As the book progressed he developed a serious drinking problem, became more and more apathetic and finally reached a point where he was on the verge of being sack. He eventually starts to get things into perspective and hints at a brighter future. The relationship between Rita and Frank began well, they complimented and trusted one another. They drifted apart and argued in the middle, but reconciled their relationship and parted on good terms. I think the main change in Rita was that she started with no choices, she had a hunger for more and great determination, which resulted in her gaining the ability to choose, and to choose wisely. I think this change in Rita was conveyed very well because as the story progresses we saw her make many decisions along the way. We saw how the choices she had to make got bigger  and bigger and how her ability to deal with the choices got better and better. The book finished with her thinking about the biggest choice; whether to have a baby or not. I think Franks character was portrayed well via his language and through his drinking habits. I really enjoyed the book and thought Russell kept me interested by adding new details along the way, we learnt more about the characters private lives as the story continued and this was an added interest. I think that the book had a good ending, as it was realistic. It showed how what they had done throughout the book and what choices they had made affected their position at the end of the book. This emphasised the theme of choice again.

The Search Essay example -- Creative Writing Search and Rescue Essays

The Search   Ã‚  Ã‚  Ã‚  Ã‚  I used to work for the F.B.I., in the Portland office. It was my childhood dream to be the one who gets the bad guy. My fiftieth birthday was in just three months. I had a wife and three children, still do, and the same job I'd had since my graduation from Quantico. We were living just outside Portland. My oldest son, John jr., was in his third year at Washington. The twins were high school seniors at this time and my pride and joy, daddy's little girls. Carolyn and I had celebrated our twenty- fifth anniversary, that's the silver one I think, the previous Thursday night. That warm July morning, I dressed for work as I had every other. Black socks and slacks, a pin striped white dress shirt, and a black jacket. I slipped on my loafers but was lost in the search for my tie. Coffee stained and still unwashed, I found it laying on the laundry room floor. I swore to myself to let Carolyn know about that. I walked into John's empty room, knowing he owned some ties. It was just as he had left it, I guess, because I'd never really gone in his room. I picked the red one he wore in his graduation pictures and slipped it over my head. I stepped into the bathroom, combed back my whitening hair, and left for the office. The early morning sun shone in through the broken blinds that I noticed hadn't been replaced as I asked. I looked over the pile of paperwork awaiting me. â€Å"Why the hell do I gotta do all these damn reports?† "Actually, you don't, not today." I turned to see a man much like myself, but older and with his piece on. He was a little taller, but with the same sagging features and large belly of my body. â€Å"I've come here to give you something new.† With that, I was handed a thick manila folder. It felt like it contained a video cassette. â€Å"All you need is in there, including my card. This is top priority, Agent Caulsworth. You will report to me on the hour with your progress. The paperwork here will wait.† The man turned and left. Outside, I heard a jet-copter quietly lift off. Funny I hadn't heard it land. I poured out the contents of the folder, the federal statement, a case history, vid cassette, and a dossier. The card that fell to the floor read 'Federal Marshall Wilson R. Franklin'. He was from the Boise office. "Must be real important for him to come all the way out here." Steve Menschke was my oldest fr... ...was the only thing that mattered to me, and he's all that's left."   Ã‚  Ã‚  Ã‚  Ã‚  I reached into my pocket and withdrew the tie. Mud concealed the red fabric. I tried to think of John. My mind strained to see his face, hear his voice. A tear rolled down my cheek and fell off my chin onto the tie. I loosened the knot and slipped it back over my head. With my sleeve, I wiped my face. I lifted the flashlight, switched it off and tossed it to him. "Take it." I turned away and started back into the world. Hendricks' team found me a few miles west of the hole. They airlifted me to the Olympia hospital. I was treated for a broken clavicle and shoulder blade, along with my ribs. The tissue damage to my back and side was extensive and I have little use of either. After two days they released me. The next day, I received a call from Franklin, in Boise. I was commended by him for putting myself on the line. He granted me early retirement, and a bonus for being injured. He asked if I might know anything about the disappearance of David Brown from his grandparents' house in the middle of the night. I told him I did not. I bid him farewell, hung up, and dialed John's number at school.

Heraldic Code of the Philippines Essay

â€Å"Don’t walk in front of me, I may not follow; don’t walk behind me, I may not lead; Just walk beside me, and be my friend†. I have one such good friend who walks beside me and who extends his hand, when I am about to slip and fall. He is my greatest asset in life, which I treasure more than anything else in this world. He is my best friend. My best friend is Tom Sangma. We come from the same neighbourhood. Our houses are situated close to each others. Both Tom and I are of same age and belong to more or less same economic background. In fact, what has cemented our friendship deep is that our families have been close to each other for a long time. My father and his father were classmates. My mother’s best friend is Tom’s mother. Another reason, which probably helped us to become good friends, is that we have grown together. We have spent our childhood days playing, fighting, learning, and enjoying together. My memory of sweet bygone days of the past is a nostalgic memory of happy days spent together in Tom’s company. Today Tom and I study in Class X in a reputed school in the town. We generally go to school together and have been lucky enough to be studying in the same class for the past ten years and more. Tom has many excellent qualities of heart and mind. His simplicity, smartness, neatness, intelligence, straightforwardness, cool temperament, pleasant behaviour, gentle ways, dutifulness, etc. have made him one of the most liked and popular students in the school. Tom’s sweet temperament is his greatest quality. He never hurts others or speaks ill of others. He has a charming personality. For several years consecutively, he has been given the ‘Best Student’ award in the school. Despite my best efforts I have never managed to reach his level. Yet I never feel jealous of him. Because he helps me more than anybody. He tries to do all he can to make me come up to his level. He never goes to any function or party or film without me. I do the same for him. Whenever I am sick, he is the first to come and see me. There is no function in my home without his presence. The same is true in his house as well. All these have combined to make our friendship deep and lasting. The best trait that I admire and like most in my friend is his disciplined life. He would not do anything that goes against accepted norms or decency. He gets up on time, does his homework always, attends school regularly, respects his teachers and elders and never indulges in unhealthy ways such as, smoking, taking alcohol, idling away time, skipping classes etc. His principle of ‘duty first- enjoyment second’ is something that I find difficult to follow, yet try to imitate. He corrects me whenever I commit any mistake. For me he is a source of inspiration, support and also a role model to imitate. I am ever grateful to the almighty for having given me such a good friend. I cherish it as my greatest treasure. I am sure our friendship will grow deeper and deeper in the years to come. I wish everyone had such friends in life. One cannot describe the thrill and the joy of journeying together in life, sharing its ups and downs, rainbows and thunders and Good Fridays and Easters. It has to be experienced.

Educational assessments

AbstractionEducational appraisals have come into examination for many old ages. In times of technological alteration, e-assessment has been a current issue in the universe of educational appraisal. The deductions of this alteration have gained considerable media coverage that range from significant support to considerable resistance. The media article â€Å"Exams are a critical lesson† by Hilary Douglas, will function as illustrations of assessment issue that are brought about by national newspapers. The paper highlights how Continuous appraisal has besides emerged as an attach toing issue to make with e-assessment. In this paper, one argues the necessity to understand the maps of appraisal in order to to the full understand why this alteration is being proposed and the ability to to the full encompass the new chances that modern engineering provides. In add-on, one outlines some of the issues that must be considered and the troubles that must be overcome before uninterrupted appraisal and e-assessment can go a complete world. In decision, it is apparent that the age of e-assessment has arrived but there are still many hurdlings to get the better of before the full potency and benefits of e-assessment are put into pattern.IntroductionIt is with no uncertainty that appraisal and proving have a strong consequence on lives and callings of immature people. Harmonizing to Black and Wiliam ( 2006:9 ) ‘Assessment in instruction must, foremost and first, function the intent of back uping larning ‘ . But what precisely is assessment? Assessment is defined by Linn and Miller ( 2006 ) as the procedure of assemblage and discoursing information from multiple and diverse beginnings in order to develop a deep apprehension of what pupils know, understand, and can make with their cognition as a consequence of their educational experiences ; the procedure culminates when assessment consequences are used to better subsequent acquisition. Assessment serves many maps and there are large educational additions associated with good appraisal as Black and Wiliam ( 1998:3 ) reappraisal in their survey: ‘All†¦ surveies show that†¦ strengthening†¦ formative appraisal produces important, and frequently significant, learning additions. These surveies range over ages ( from 5-year olds to university undergraduates ) , across several school topics, and over several states However, in many cases, appraisal due to patterned advance intents in life may be strictly seen as unreal hurdlings to traverse over in immature people quest for employment or farther instruction. This paper will foreground issues sing maps of appraisal that will assist to understand, how foremost and first, the intent is to back up acquisition. In the eyes of many educational professional, an extraordinary assortment of classroom-targeted enterprises have been unleashed on schools over the last decennary and more. All the enterprises with the same general purpose: the betterment of student acquisition. Appraisal by instructors, whether formative or summational, is one of these developments that are considered to offer important potency for bettering student ‘s acquisition ( Harlen, 1997 ) . This development is on traveling and cogent evidence of it is one of the latest media articles headlined â€Å"Exams are a critical lesson† ( July 19th, 2009 ) The article by Hilary Douglas identifies current tendencies and issues sing maps of appraisal and current and future appraisal patterns. In peculiar the article focuses on a statement by the caput of the Cambridge Assessment exam board saying â€Å"there will be a displacement from traditional high-stake summational appraisals to be replaced by computerised online testing.† The thought behind the strategy would be that pupils could take a trial whenever they are ready and resit these as many times as necessary to be able to acquire a good grade. Continuous appraisal would wholly replace the three-hour written test, instead than a mix of appraisal of coursework and traditional testing which is the norm. As Douglas ( 2009 ) indicates, nine old ages ago, Curriculum 2000 was introduced when students were allowed to recognition their classs as AS students at the terminal of their first twelvemonth. However, the debut of uninterrupted appraisal, as proposed in the article non in its signifier land breakage. Originally A-Levels were assessed through one set of tests at the terminal of a biennial class. They were besides allowed for the first clip to take tests as many times as they liked until they and their instructors felt they had achieved the optimal grade. Even though exam boards such as OCR have already tested e-assessment in environmental and land-based scientific discipline since 2007, and have 1,800 campaigners and 80 schools ( Douglas, 2009 ) utilizing it this summer turn outing to be popular for both pupils and instructors likewise, many educational experts warn that the move could be an unfastened door to the most dismaying cheating and that proving all students around the state in the same manner at the same clip and under the same fortunes is the lone true manner to be able to compare the consequences in a meaningful manner. In add-on, Alan Smithers ( cited in Douglas, 2009 ) professor of instruction at Buckinghamshire University, feels that the move must be stopped at all costs. â€Å"Making opinion about public presentations is n't easy, † he says. â€Å"The best manner of making it is cold-eyed appraisal of pupils undertaking the same undertakings under the same conditions.† It is apparent that a move from traditional summational appraisal to uninterrupted appraisal and e-assessment will convey both challenges and chances sing issues of appraisal and perchance contextualise the map of appraisal. This paper will get down with an scrutiny on the map of appraisal and pay peculiar attending to issues this alteration could convey to schools, colleges and more significantly, pupils. Current appraisal patterns in uninterrupted appraisal and e-assessment will all assistance in understanding the issues this alteration in assessment pattern may hold.Functions of Educational AssessmentHarmonizing to Newton ( 2007 ) when sing optimum design features for future assessment systems, it is necessary to bear in head the underlying intent of those systems. Overall it must be taken into history that a system which is tantrum for one intent will non needfully be fit for all intents and this is something uninterrupted appraisal and e-assessment proposals need to bare into co nsideration. The term ‘assessment intent ‘ may be interpreted in a assortment of different ways one will place the three degrees as mentioned by Newton ( 2007 ) 1. Judgemental Level ( concerns proficient purpose of an assessment event e.g. intent is to deduce standards-referenced opinion expressed as a class, use normally associated in official paperss ) 2. Decision Level ( concerns the usage of an assessment opinion, the determination, action, procedure it enables e.g. the intent is to back up a choice determination for entry into higher instruction ) 3. Impact Level ( concerns the intended impacts of running an appraisal system e.g. the intent are to guarantee that pupils remain motivated, and that all pupils learn a common nucleus for each topic ) ( Newton, 2007 ) It is of import to understand that where the distinct significances are non distinguished clearly, their distinguishable deduction for assessment design may go ill-defined. In this state of affairs, policy argument is likely to be unfocused and system design is likely to continue inefficaciously ( Newton, 2007 ) . So at what degree are the new proposals aimed at? The alteration proposed by the caput of Cambridge Assessment exam board brings a alteration to high-stakes summational appraisal. ‘High Stakes ‘ a term used to denote those state of affairss where involvement in appraisal goes beyond the immediate domain of educational measuring and beyond those persons who sit the trials ( Messick, 1999 ) . In add-on, as many authors have pointed out, the bets may be higher but the proficient jobs associated with appraisal remain the same in that all appraisal, whether high-stake or low-stakes, demands to be valid and dependable ( Linn, 2000:1 ) . American Educational Research Association ( 2000 ) noted that: If high-stakes testing plans are implemented in fortunes where educational resources are unequal or where test deficiency sufficient dependability and cogency for their intended intent, there is the possible for existent injury. Therefore if anything needs to predominate from these alterations in appraisal, are the demands for them to be valid and dependable. So what alterations are being proposed and what differences are at that place in signifiers of appraisal? This now leads one to the non covetous undertaking of briefly happening a differentiation between summational and formative appraisal. It is non 1s purpose to supply an extended literature research on formative and summational appraisal, but a on the job theory that has been taken into history throughout this paper. The position from Harlem and James ( 1997 ) and Harlem ( 2005 ) theory in summational and formative appraisal has been taken into history. Harlem and James ( 1997:372 ) attempted to separate formative from summational appraisal by naming contrasting features, for illustration, summational appraisal demands to prioritize dependability, while formative appraisal demands to prioritize cogency and utility ; formative appraisal dainties inconsistent grounds as enlightening, while summational appraisal dainties inconsistent values as mistakes. Harlen ( 2005 ) later developed this statement, and farther clarified the differentiation between formative and summational as follows: The two chief intents of appraisal discussed in this article are for assisting acquisition and for sum uping acquisition. It is sometimes hard to avoid mentioning to these as if they were different signifiers or types of appraisal. They are non. They are discussed individually merely because they have different intents ; so the same information, gathered in the same manner, would be called formative if it were used to assist acquisition and instruction, or summational if it were non so utilised but merely employed for entering and describing. While there is a individual clear usage if appraisal is to function a formative intent, in the instance of summational appraisal there are assorted ways in which the information about pupil accomplishment at a certain clip is used. ( Harlen, 2005, p. 208 ) Therefore, for intent of this paper it is utile to foreground the points that people frequently seem to believe that the differentiation turns on the nature of the assessment event i.e. , the usage to which assessment opinion will be put. One must take into consideration that whatever the nature of a opinion there would be nil formative occurrence unless the opinion was used in an effort to better acquisition. Therefore, even though one might measure via summational agencies, there is ever the handiness to supply formative feedback and manager pupils on where they have gone incorrect. This may be done through uninterrupted appraisal.Continuous AppraisalThe abolition of the traditional three hr test to uninterrupted assessment brings issues and chances within the educational constitutions. Continuous appraisal, harmonizing to Federal Ministry of Education, Science and Technology ( FMEST, 1985 ) , is defined as a mechanism whereby the concluding scaling of a pupil in cognitive, affecti onal and psychomotor spheres of behavior takes history, in a systematic manner, all his public presentations during a given period of schooling ; such an appraisal involves the usage of a great assortment of manners of rating for the intents of steering and bettering acquisition and public presentation of the pupil. This manner of appraisal is considered equal for appraisal of pupils ‘ acquisition because it is comprehensive, cumulative, systematic, counsel and diagnostic oriented. Having the ability to continuously measure will ease the instructor to understand where the pupil is holding trouble and act through formative appraisal. But what is the intent of this alteration and associating back to the old subdivision, what is the intent of this educational appraisal? In the instance of uninterrupted appraisal, its purpose tantrums on an impact degree, which concerns the intended impact is of running an appraisal system that attempts to guarantee pupils remain motivated, and that all pupils learn a common nucleus for each topic. It is here where even though the proposal is to convey in computerised online testing ( which shall be dealt with later on in e-assessment ) that will bring forth chiefly summational opinion may be used for formative appraisal. The ability for pupils to resit exams allows both the pupil and instructor to utilize a summational appraisal and if the pupil was unsuccessful in their first effort, utilise the consequence for formative intents. How? This allows the pupil and instructor to turn to where precisely they have gone incorrect leting assessment processs and patterns to develop to back up acquisition and underpin instead than undermine pupil assurance, accomplishment and advancement. James and Pedder ( 2006:110 ) provinces, ‘feedback focused on assisting pupils to better sharing standards of quality ‘ . This point can non be understated as the type and quality of feedback to the pupil via formative appraisal has been seen as important in other surveies ( Black and Wilia ms, 2008 ) . However, will this alteration make a difference to pupil ‘s perceptual experience of larning and more so of appraisal? Will these alterations bring large cultural differences to educational constitutions? Entwistle ( 1991 ) helps one to understand some of the issues with respects to uninterrupted appraisal and current patterns. The survey had findings that the pupil ‘s perceptual experience of the acquisition environment determines how they learn and non needfully the educational context in itself. It is apparent from the survey that formative appraisal and uninterrupted appraisal may hold a important consequence on what pupils learn and particularly how they learn. Gibbs ( 1999 ) has hence suggested that if pupils see assessment as the course of study, effectual instruction demands to utilize this cognition, in order to utilize the power of appraisal strategically to assist pupils larn. Biggs ( 2002 ) echoes the same fact when he says that pupils learn what they think will be assessed instead than what is in the course of study. The alterations from traditional appraisal to uninterrupted e-assessment will conversely, have an impact on the scholar ‘s experience of rating and appraisal finding the manner in which they approaches larning ( Struvyen et al, 2005 ) . Appraisal can therefore be looked upon logically and through empirical observation as one of the specifying characteristics of pupils ‘ attacks to larning ( Entwistle and Entwistle, 1991 ; Ramsden, 1997 ) . Within the proposed appraisal in the article, pupils are likely to take a strategic or accomplishing attack to acquisition, where Entwistle et Al ( 2001 ) believes the pupil ‘s purpose will be to accomplish the highest possible classs by utilizing good organised and painstaking survey methods and effectual clip direction, something that one along with perchance many other instructors see as a positive and encouraging alteration. Interestingly, Marton and Saljo ( 1997 ) survey serves as a good illustration in finding relation between attacks to larning and appraisal. A sum of 153 pupils from four topics in Engineering and Business degree watercourses participated in the survey from a University. Results showed that uninterrupted appraisals were preferred over a individual appraisal by a 78 % bulk. Some of the popular grounds for the penchant were easiness to analyze little subjects and hence being able to hit good Markss easy. The coursework Markss can be better because of the burdening given to each of the uninterrupted appraisal every bit good as the ability to construct a stronger foundation as one move from one subject to the other were remarks in favor of uninterrupted appraisals. It forces one to larn subjects decently earlier traveling to following subject. Each subject is given accent throughout the uninterrupted manner of appraisal ( Marton and Saljo ( 1997 ) . However, non all remarks are favorable. Remarks against this type of appraisals included ; excessively many appraisals robs one ‘s clip to larn other topics and frequent appraisal maintain you on alteration manner all of the clip, no relaxation ( Marton and Saljo cited in Jacob et Al, 2006 ) . What is apparent from research is that uninterrupted appraisal helps to look into on acquisition and that larning happens in stairss, non merely for the concluding test. Does this point to larning scheme adopted by the pupils? They seem to necessitate a cheque on their acquisition through trials, which they prefer in little units. But the logical thinking behind this was non to so much the avidity to get the hang the subject as such, but merely to do certain that their marking was helped. Associating to coursework classs, the survey concluded that those campaigners who follow a series of uninterrupted appraisals produce an enviable bulk of Higher Achievers. However, informations shows a negatively skewered distribution. This may hold deduction on the surveies dependability as the being of positively or negatively skewered distributions will be given to cut down the dependability of the trial. However, these consequences are typical for coursework classs particularly if they are designed to prove competence. In uninterrupted appraisal, with respects to assignments, pupils are supposed to seek for and synthesize information on the footing of its relevancy to the given assignment. If formative feedback from instructors is performed right, it should help in the acquisition of pupils. Overall, if the pupil completes and is able to finish the undertakings, they will obtain higher Markss. The survey besides deliberated that those pupils who did non execute in uninterrupted appraisal experienced poorer classs which were reasonably usually distributed. Is the power and influence of coursework evident here? Are some kids helped more than others? It is here where instruction constitution may run the hazard of pass oning to pupils that each unit/coursework etc as stepping rocks to enfranchisement instead than a life-long acquisition experience. Such perceptual experience of pupils encourage a strategic attack to their surveies, and allow them fall back to plagiarism, rip offing and utilizing ‘Rules of the game ‘ or ROGs as Norton et Al ( 2001 ) name. ROGs are an indicant that pupils perceive a hidden course of study where coachs say they want certain things in the appraisal undertaking. Here inquiries of cogency may stand for an issue. Taking into history Cook and Campell ( 1979 ) definition of cogency which is the â€Å"best available estimate to the truth or falseness of a given illation, proposition or conclusion† one has to measure whether pupils are accomplishing better classs because they are motivated, working harder, get bying with smaller units or is it to make with an over inclination for pupils to have coaching and specific information that helps them ‘push-up ‘ their classs. In add-on, Black et Al ( 2006 ) besides reiterates this by bespeaking that far from advancing an orientation towards pupil liberty, such patterns are interpreted as techniques to guarantee award accomplishment and likely aid pupils who are more dependent on their coachs and assessors instead than less dependent ( Torrence, 2007 ) . Modularization of A Levels is a perfect illustration where greater transparence of larning results and the standards by which they are judged have benefited scholars in footings of the increasing Numberss of scholars retained in formal instruction and preparation and the scope and Numberss of awards which they achieve ( Savory et al, 2003 ) . Clarity in assessment results, procedures and standards has underpinned the widespread usage of coaching, pattern and proviso of formative feedback to hike single and institutional accomplishment. In add-on, research grounds reported suggests that such transparence encourages instrumentalism ( Savory et al, 2003 ) . Transparency of aims together with extended coaching and pattern to assist scholars run into them is in danger of taking the challenges of acquisition and cut downing the quality and cogency of results achieved. This is mentioned by Torrance ( 2007:282 ) as a move from appraisal of acquisition, through the presently popular thought of appraisal for acquisition, to assessment as acquisition, where appraisal processs and patterns come wholly to rule the acquisition experience, and ‘criteria conformity ‘ comes to replace ‘learning ‘ and is something that needs to be to the full researched if execution of uninterrupted appraisal and unrestricted resit options are traveling to be made available for all curriculum topics. However, at this phase it is imperative to foreground the fact that the survey by ( Marton and Saljo, 1997 ) serves as a good i ndex of what may be experienced in educational scene. However, with a sample size of 153 from merely four topics in Engineering and Business grades from merely one University might demo perceptual experiences and consequences which are important to that particular survey, but might non needfully expose an association to other educational constitutions. This now leads one to measuring e-assessment and the map of its appraisal and current appraisal patterns.E-assessmentThe proposal of presenting e-assessment brings strengths, failings, chances and menaces to any educational constitution. But before we deal with these it is of import to understand precisely what e-assessment means. The term e-assessment covers the assortment of ways in which computing machines can be used to help the appraisal procedure. This might include utilizing computing machines to administrate an appraisal for formative or summational appraisal ( Attali and Burstein, 2006 ) . The proposal of presenting e-assessm ent is non a new one. Ken Boston ( Chief executive of the Qualification and Curriculum Authority in 2004 ) was bullish about the power of engineering to transform the educational experience of 1000000s of students, but that was back in 2004, and few experts would state that he has been proved right. In fact, five old ages on, none of the anticipations Boston made on that twenty-four hours has turned out to be right. For many in this field, the large inquiry has been why, given that technological alteration has happened rapidly in so many other countries of life, the gait of reform in this country means that, for most students taking tests still means scrabbling on paper. However, Multiple-choice inquiries ( MCQs ) are a perfect illustration on how educational constitutions have embraced the development of e-assessment. MCQ can be used as a agency of supplementing or even replacing appraisal patterns. The growing in this method of appraisal has been driven by wider alterations in the higher instruction environment such as the turning Numberss of pupils, modularisation and the increased handiness of computing machine webs. MCQ ‘s are seen as a manner of heightening chances for rapid feedback to pupils every bit good as a manner of salvaging staff clip in taging. However, there are recognized restrictions with this method. First, research workers discourage the usage of MCQ, reasoning they promote memorization and factual callback, and do non promote high-ranking cognitive procedures ( Scouller, 1998 ) . Some research workers, nevertheless, maintain that this depends on how the trials are constructed and that they can be used to measure acquisitio n at higher cognitive degrees ( Johnstone & A ; Arnbusaidi, 2000 ) . The advantage of MCQ with respects to assessment is its high degree of dependability that can be good as an alternate signifier of appraisal. However, the existent trouble for e-assessment has to make with the nature of analyzing. It is a high-stake activity as we have observed antecedently, which is closely scrutinised. Boyle ( 2009 ) deliberates that there is echt antipathy to put on the line in this country, within authorities, within suppliers of appraisal, amongst pupils, parents and staff. Because of this, things will be given to travel easy. Boyle ( 2009 ) adds that e-assessment nowadayss some serious practical challenges. Having an full twelvemonth group sit and take an test at the same clip, as happens with major conventional GCSEs now, would ask holding two sets of computing machines ; one for those taking the trials and another for other twelvemonth groups, which is expensive and frequently impractical. This therefore brings with it proficient troubles in implementing such initiatives.. Taking into consideration past experiences viz. the compulsory ICT test for 14 year-olds it is non difficult to see why the predicted roar of e-assessment has non occurred. In 2007, authorities had to draw the stopper on a compulsory ICT test for 14 year-olds, developed over five old ages at the cost of ?26 million ( Mansell, 2009 ) after it was found to bring forth consequences for students that were dramatically different from instructor ‘s ain appraisals of their charges ‘ work. It was due to go statutory last twelvemonth, but in the terminal, was offered merely voluntary to schools. Repercussions were highlighted by Andre Harland, head of the Examination Officers ‘ Association stated, â€Å"it did foreground some possible large hazards and jobs with e-assessment. The trial involved taking computing machines in a school out of operation at the same clip, and it merely did non turn out deliverable in the end.† An issue with dependability in summational appr aisal is a cardinal defect as Harlem and James ( 1997 ) reiterate, dependability in summational appraisal is important. In add-on, Boyle ( cited in Mansell, 2009 ) and functionaries from all five tests boards in England, Wales and Northern Ireland, sets out other jobs, including that it may be easier to rip off by looking over person ‘s shoulder at what is on screen, instead than on a desk, and guaranting that high-tech testing does non present some alteration in the criterion of the test. However, it is 1s belief that the proposal made by Lebus is one that focuses chiefly on the computerisation of the externally set and graded high bets summational scrutinies of educational attainment that lead to makings. Surprisingly, was an article by Polly Curtis in the Guardian rubrics â€Å"Computerised proving probably to replace traditional tests, says caput of board† released in the 12th July 2009, stated that Lebus said â€Å"that traditional-style test would still be available for those who preferred them, but the new system would profit pupils who are exam-phobic. There are some people evidently who get really frightened by tests or could n't for other grounds do them well.† One must pull importance to this statement. Merely a hebdomad after the article Hilary Douglas ( 2009 ) stated that uninterrupted appraisal would wholly replace traditional tests, non supplying all the information. This brings to light issues with dependability and cogency of information the media publishes covering with of import appraisal issues. This demonstrates the ballyhoo artist attack to a serious issues sing instruction, and foremost the use of information. In the instance of A-Levels we already implement uninterrupted appraisal and supply resit opportunities the computerisation of these would be a good starting point for high interest summational appraisal. But why computerise? Why computerize a conventional trial if the new trial is meant to measure precisely the same things? Possibly the most common grounds given are that computerised will delver ; I. Increased efficiency/lower costs II. Greater flexibleness sing disposal ( e.g. trial on demand V trials at fixed – and infrequent – times ) III. Instant scores/feedback IV. Fewer mistakes V. Positive promotion through being seen to be ‘up-to-date ‘ VI. The first measure that must be taken earlier more sophisticated computer-based appraisals can be introduced. ( Raikes and Harding, 2003 ) At present, most of the academic makings aimed at 16-18 year-olds in the UK are assessed through a mixture of coursework and summational pen and paper scrutinies. Written scrutinies are still handwritten on paper, and are frequently criticised for restraining instruction, suppressing schoolroom invention, smothering pupil ‘s creativeness and for being progressively divorced from an of all time more technological universe ( Heppel, 2003 ) . There is hence force per unit area to develop appraisals that make full usage it IT developments, non merely in low-stake appraisals but high-stakes likewise. In pattern this can be difficult to accomplish for two chief grounds, even if the advanced appraisals exist. First, schools and colleges will all differ in the quality and measure of their ICT substructure, in the ICT support and in the degree of ICT accomplishments possessed by instructors. In such fortunes it would be really hard for an scrutiny board to present a high bets, advanced computer-based trial that would be accessible to all schools and colleges, and furthermore, which would non disfavor pupils from schools and colleges with destitute ICT resources. In add-on, likely demands for equity in appraisal would necessitate a traditional paper-based test. Second, a really high value is placed in the UK on the care of ‘standards ‘ from twelvemonth to twelvemonth, and this would be hard to show clearly since written trials define past criterions. The contention stirred up in the UK in 2002 about the consequences of new A Level scrutinies was caused mostly by ‘the absence of a clear apprehension of the criterions or degrees of demand ‘ ( Tomlinson, 2002 ) and how they relate to the old A Level system ; this once more serves as another illustration as the dangers involved in presenting wholly new types of high bets appraisal. Both equity and the criterions troubles may be addressed by first computerizing bing trials. Equivalent pen and paper and computing machine versions of the same trial may so be analogue that will ease all stakeholder to so concentrate on the migration from pen and paper to computing machine ( Raikes and Harding, 2003 ) .When about everyone is taking the trials on computing machine, it becomes easier to present some invention. By holding a procedure that moves in gradual phases it is believed it will ease the move towards valid trials whilst cut downing the concern about criterions. However, there are already cases where e-assessment is being implemented and demoing mark of success. Literature from Linn and Miller ( 2005 ) that clip required is a major issue when it comes to assignment taging. Two chief factors are to be considered: clip spent on administrative undertakings and the clip really spent on prosecuting the pupils work and the proviso of quality feedback. E-tools are developing and conveying positive alterations to instructors. The country were e-tools can do a existent impact on efficiency in disposal: providing paperss, easy accessible to all involved, accepting assignments entries, covering with safe and unafraid storage, pull offing the distribution of assignments to markers and easing the communicating within the marker squad ; returning taging sheets etc some in add-on to advantages mentioned earlier. Detecting plagiarism was another issue that was mentioned as a major advantage of utilizing e-tools. Having the assignment in electronic signifier means it can be cross-checked against past twelvemonth ‘s assignments and current assignments, and an e-tool like Turnitin can besides test for citations from text books. ( Heinrich et al, 2009 ) Overall, if research documents encountered and the deficiency of cardinal scheme from the authorities is any indicant to travel by, one believes that the execution of e-assessment when it comes to uninterrupted summational appraisals still has a batch of development to do, particularly if past mistakes are to be rectified and assurance in it dependability and cogency starts to better. There are promoting developments and as Professor Peter Tymms, of Durham University says: â€Å"The test boards are all on it, they are all believing about it, and seeking difficult to make it. But they have non yet found their manner frontward yet.† It hence leads one to believe that it is merely a affair of clip before e-assessment replaces traditional signifier of appraisal.DecisionThe purpose of this paper was to critically near appraisal patterns, maps of appraisal and interrogate current appraisal patterns through a media history. Continuous appraisal, formative and summational appraisal an d e-assessment were the chief subjects developed by the media article. Within these sub groups there were common subjects covering with cogency and dependability that helped understand the possible impacts these development in appraisal may hold for pupils, instructors and the wider universe. Overall, it is apparent from the research that the map of appraisal is of great importance when planning to alter any assessment systems. The passage from traditional summational appraisal to uninterrupted appraisal by the caput of Cambridge Assessment exam board leads one to believe that the assessment way appraisal boards are heading is one of impact functional degree, which concerns running an appraisal system that attempts to guarantee pupils remain motivated, and that all pupils learn a common nucleus for each topic. Due attention and attending will be needed, in order non to put inordinate demand on a criterion-based appraisal. This will take pedagogues to measure what the scholar can make in relation to the undertaking required of them and put small involvement on placing what else the scholar can make. The handiness of limitless resits and importance of criterion-based appraisals may hold serious larning reverberations as a displacement in accent of doing certain that pupils hiting are helped instead than an avidity to get the hang the subject. There has been a move from ‘assessment of larning ‘ to assessment for larning ‘ and now assessment as larning ‘ ( Torrance, 2007 ) The proposal made with respects to execution of uninterrupted appraisal as a series of e-assessments is non intended to to the full replace the traditional schoolroom appraisal and that is something everyone in educational constitutions, One believes, needs to take into history. But it can efficaciously complement the latter particularly in the context of big categories. MCQs have demonstrated successful illustrations on how to include e-assessment into the schoolrooms. Increased efficiency, greater flexibleness in working and instant tonss are some of the advantages e-assessment has brought into schoolrooms and schools. However, at this minute in clip, and taking past experiences into consideration, implementing e-assessment in footings of high-stake appraisal options will be difficult to accomplish ; either due to quality and measure of substructure or equity and criterions. It is true that impulse is constructing and as Durham University Professor, Peter Tymms says â€Å"the test boards are all on to it, they are all believing about it, seeking difficult to make it. But they have non yet wholly found their manner frontward yet. There is no uncertainty that the age of e-assessment is upon us. However, there are still many hurdlings to get the better of before the full potency and benefits of e-assessment are gained.Reference ListAmerican Educational Research Association, American Psychological Association and National Council on Measurement in Education ( 1999 ) Standards for educational and psychological testing ( Washington, DC, American Educational Research Association ) . Bigg, J ( 2002 ) cited in Jacob, S. , M and Issac, B. ( 2006 ) Impact on pupils larning from traditional uninterrupted appraisal and an e-assessment proposal. The Tenth Pacific Asia Conference on Information Systems. Black, P. J. ( 1998 ) Testing: friend or foe? The theory and pattern of appraisal and testing ( London, Falmer Press ) . Black, P. J. & A ; Wiliam, D. ( 2003 ) ‘In congratulations of educational research ‘ : formative appraisal, British Educational Research Journal, 29 ( 5 ) , 623-637. Black, P. , & A ; Wiliam, D. ( 1998b ) . Inside the black box: Elevation criterions through schoolroom appraisal. London: GL Assessment. Boston, K ( 2004 ) cited in Douglas, H. ( 2009 ) Exams are a critical lesson. July 19th 2009 in hypertext transfer protocol: //www.express.co.uk Curtis, P. ( 2009 ) Computerised proving probably to replace traditional tests, says caput of board. July 12th 2009 in hypertext transfer protocol: //www.guardian.co.uk Douglas, H. ( 2009 ) Exams are a critical lesson. July 19th 2009 in hypertext transfer protocol: //www.express.co.uk Entwistle, N. , J. ( 1991 ) Approaches to larn and perceptual experiences of the acquisition environment. Introduction to the particular issues. Higher Education, 22, pp 201-204. Entwistle, N. , J. and Walker, P. ( 2001 ) Stretegic watchfulness and expanded consciousness within sophisticated constructs of learning. Instructional Science, Vol 28, 335-361 Gibbs, G. ( 1999 ) Using assessment strategically to alter the manner pupils learn, In Jacob, S. , M and Issac, B. ( 2006 ) Impact on pupils larning from traditional uninterrupted appraisal and an e-assessment proposal. The Tenth Pacific Asia Conference on Information Systems. Henrick, E. , Milne, J. , Ramsay, A. , Morrison, D. ( 2009 ) Recommendations for the usage of e-tools for betterments around assignment taging quality. Assessment and Evaluation in Higher Education, Vol 34 ( 4 ) pp 469-479.. Jacob, S. , M and Issac, B. ( 2006 ) Impact on pupils larning from traditional uninterrupted appraisal and an e-assessment proposal. The Tenth Pacific Asia Conference on Information Systems. James, M. and Pedder, D. ( 2006 ) Beyond Method: Appraisal and Learning Practices and Values. The Curriculum Journal, 17 ( 2 ) , 109-138 Linn, R. L. , ( 2000 ) Assessment and Accountability, Educational Researcher, vol. 29 ( 2 ) , 4-14. Linn, R.L. , and M.D. Miller. 2005. Measurement and appraisal in learning. Columbus, OH: Pearson Merrill Prentice Hall. Mansell, W. ( 2009 ) Why has n't e-assessment arrived more rapidly? July 21st 2001 in hypertext transfer protocol: //www.guardian.co.uk Messick, S. , ( 1999 ) , Performance appraisal, in F. M. Ottobre ( Ed. ) , The function of measuring and rating in instruction policy. UNESCO Printing: Paris Marton, F. and Saljo, R. ( 1997 ) cited in Jacob, S. , M and Issac, B. ( 2006 ) Impact on pupils larning from traditional uninterrupted appraisal and an e-assessment proposal. The Tenth Pacific Asia Conference on Information Systems. Newton, P. E. ( 2007 ) Clarifying the intents of educational appraisal. Appraisal in Education: Principles, Policy and Practice. Vol 14 ( 2 ) 149-170 Raikes, N. , Harding, R. , The horseless passenger car phase: replacing conventional steps. Appraisal in Education, vol. 10, ( 3 ) , 267-277. Savory, C. , Hodgson, A. and Spours, K. ( 2003 ) A general or vocational making? The Advanced Vocational Certificate of Education ( AVCA ) ( 7 ) Smithers, A ( 2009 ) cited in Douglas, H. ( 2009 ) Exams are a critical lesson. July 19th 2009 in hypertext transfer protocol: //www.express.co.uk Struyven, K. , Dochy, P. & A ; Jansenns, S. ( 2005 ) Students perceptual experiences about rating and appraisal in higher instruction: a reappraisal. Assessment and Evaluation in Higher Education, Vol 30 ( 4 ) , 325-341 Tomlinson, M. ( 2002 ) Inquiry into A degree criterions, Final Report ( London, Department for Education and Skills, available from hypertext transfer protocol: //www.dfes.gov.uk/alevelsinquiry/ Torrance, H. ( 2007 ) Assessment as larning? How the usage of expressed larning aims, appraisal standards and feedback in post-secondary instruction and preparation can come to rule acquisition. Appraisal in Education: Principles Policy and Practice, Vol 14, ( 3 ) , 281-294

Phosphate Removal by Struvite Crystallization

Phosphate Removal by Struvite Crystallization Abstract Human activities continue to threaten the purity of water by releasing pollutants from industries and domestic water usage. When phosphates in aqueous solutions gain access into water bodies, they lead to the abnormal growth of algae, which reduces the concentration of dissolved oxygen. Therefore, phosphates in aqueous solutions must be reduced before the solutions are released into water bodies.Advertising We will write a custom research paper sample on Phosphate Removal by Struvite Crystallization specifically for you for only $16.05 $11/page Learn More In addition, high phosphate prices necessitate techniques that enable the recycling of phosphates. One method of removing phosphates from aqueous solutions involves the formation of struvite, a complex salt made of magnesium, ammonium and phosphate. Struvite crystallization requires an alkaline pH between 8 and 10 and temperatures between 20 oC and 25 oC. A delicate balance in the quantities of key ions such as magnesium, phosphate and ammonium is necessary for the success of the method. Therefore, the process can be modified through the addition of the deficient ions. Various studies report success of the method with varying quantities of phosphates recovered as struvite from different aqueous solutions. The recovered struvite is commonly applied as fertilizer thereby recycling phosphates. Therefore, it can be concluded that phosphate removal through struvite crystallization is an economical and efficient recovering phosphates from aqueous solutions. Introduction Domestic water use and industrial activities lead to the production of aqueous solutions in the form of wastewater, which hold certain quantities of useful elements, for instance, magnesium, phosphorus and nitrogen. However, these substances have a negative impact on the aquatic environment when present at high concentrations. Therefore, it is important to safeguard the integrity of water bodies by ensuring that the se elements do not gain access into water bodies at lethal concentrations. Several techniques have been developed to reduce the amount of phosphates in aqueous solutions before they are discharged into water bodies. This paper looks at struvite crystallization as a method of phosphate removal from aqueous solutions. Phosphate Chemistry Le Corre et al. describe a phosphate as a salt formed from phosphoric acid [1]. Phosphates can also exist as organic compounds in the form of organophosphates, which are esters of phosphoric acid. The phosphate ion comprises five atoms, which are a phosphorus atom and four oxygen atoms arranged in a tetrahedral fashion with the phosphorus atom enclosed by the oxygen atoms.Advertising Looking for research paper on chemistry? Let's see if we can help you! Get your first paper with 15% OFF Learn More The chemical formula of the phosphate ion is written as PO43-. The molecular weight of this radical is equivalent to 94.97 grams per mole. The creation of a phosphate compound entails the addition of an atom with a positive charge to the phosphate radical, which possesses a negative charge. As a result, an ionic complex is produced. The precise solubility of phosphates relies on the positively charged atom that combines with the phosphate anion. For example, phosphates of alkali metals (rubidium, cesium, potassium, and sodium) as well as ammonium are soluble in water. The phosphates of other metals only show solubility to a limited extent. Sources of Phosphates The element phosphorus exists naturally in the form of phosphates, which are present in rocks. The pure form of phosphorus is usually obtained from mined phosphate rocks. Capdevielle et al. indicate that approximately 90% of all the mined phosphorus is used in farming as synthetic fertilizers due to the importance of phosphates to the health of flora and fauna [2]. The remaining 10% of phosphorus is used in industrial applications such as the manufacture of detergents (sodium tripolyphosphates- Na5P3O10), production of safety matches, gasoline additives, plastics, and transistors in electronic gadgets. A small fraction is used as food supplements as well as in the production of phosphate salts. The phosphate salts are used by clinicians to treat low phosphate levels in the blood and to counter the effect of excessive blood calcium levels. Other medical uses of phosphate salts are as a laxative and antacid. Therefore, urine tends to have significant quantities of phosphates. Most of the industrial processes release their effluents into water bodies such as lakes and rivers. These effluents often lead to detrimental effects on animals living in these water bodies. The domestic use of detergents releases phosphates into water bodies via drainage pipes, which further exacerbates the problem of phosphate pollution. In addition, the natural process of decomposition of organic substances releases significant quantities of phosphorus into t he surroundings. The naturally occurring sources of phosphates such as fluorapatite may leach and release phosphates into water bodies. Wastewater treatment plants also release substantial amounts of phosphates into the environment.Advertising We will write a custom research paper sample on Phosphate Removal by Struvite Crystallization specifically for you for only $16.05 $11/page Learn More Harmful Effects of Phosphates Surface runoff of phosphates from agricultural lands, domestic water use and industries causes the eutrophication of water bodies. US EPA explains that eutrophication arises when algae present in water bodies grow at a rate much faster than is safe for a balanced ecosystem [3]. As a result, the water body becomes clogged with algae as well as other green plants that gradually turn the water body into a swamp and ultimately into a meadow. Eutrophication also affects the animals that live in the water. According to Mylavarapu [4], the excessi ve plant growth leads to a deficit of oxygen resulting in the suffocation (anoxia) of aquatic animals. In humans, excessive consumption of phosphates in food or as supplements leads to complications in patients with renal failure due to the spontaneous crystallization of phosphates as struvite hence causing bladder stones. Removal of Phosphates According to Le Corre et al. [1], the harmful effects of phosphates in water bodies have led to the formulation of regulations to monitor the quantities of phosphates that are allowed into water bodies. Wastewater treatment plants are usually responsible for the detoxification of aqueous solutions in the form of wastewater. However, most of these plants receive wastewater that contains phosphates at levels that surpass the maximum allowable limits. Therefore, there is a need to reduce the quantities of phosphates in effluents from various processes before discharge into water bodies. Consequently, a number of techniques that remove phosphates have been devised. These methods include physical, biological and chemical methods. Physical methods of phosphate removal include filtration to get rid of particulate phosphates. Filtration is efficient if a large proportion of the total suspended solids comprises phosphates. The wastewater is passed through sand or membranes. Membranes have an added advantage of removing dissolved phosphates in addition to the particulate phosphates. Membrane bioreactors, tertiary membrane filtration and reverse osmosis structures have been developed.Advertising Looking for research paper on chemistry? Let's see if we can help you! Get your first paper with 15% OFF Learn More Chemical methods include precipitation and crystallization. In precipitation, certain elements are added to the wastewater at different points. These elements react with phosphate ions forming insoluble phosphate salts that are removed by filtration or crystallization. Precipitation is thought to remove phosphates to levels between 0.005 and 0.04 mg per litre of wastewater. However, the key disadvantage of precipitation is that it increases the amount of sludge produced. A novel technique is the elimination of phosphates with the formation of struvite, which is a white crystalline solid. Struvite is a compound produced by the unprompted combination of ammonium, magnesium and phosphates in equimolar quantities. The following equation illustrates the chemical reaction that leads to struvite formation. Mg2+ + NH4+ +HnPO43-n + 6H2O = MgNH4PO4.6H2O + nH+ Biological methods of phosphate removal include assimilation and enhanced biological phosphorus removal (EBPR). During the process of a ssimilation, wastewater is put in treatment ponds containing photosynthetic plants such as algae, which have huge phosphate requirements. Wastewater is also applied to agricultural land in the course of planting seasons. EBPR uses phosphate-accumulating organisms (PAOs) that amass polyphosphates as energy stores in specialized granules. EBPR is very effective and has the capability of attaining phosphate levels as low as 0.1 milligrams in effluent. Research Results Struvite crystallization is a method that leads to the formation of struvite, a chemical compound consisting of magnesium, aluminium and phosphate at equal concentrations. The process was named after a German geographer Heinrich Christian Gottfried von Struve who first identified it. At optimum conditions of temperature and pH, magnesium, phosphate and ammonium ions present in an aqueous solution crystallize spontaneously to form struvite. The process can also occur naturally in animal urine and seafood. Struvite crystall ization is used as a technique for eliminating phosphate ions from aquatic solutions prior to the disposal of such solutions. The process yields struvite, which is effective as manure in the agricultural sector. In addition, struvite crystallization is useful in the recycling of phosphates due to the escalating price of phosphates. Sensitive water purification processes such as reverse osmosis also benefit from struvite crystallization as a pre-treatment method for wastewater. The process has found immense applications in sewage and wastewater treatment plants. Removal of Phosphorus from Landfill Leachate and the Effect of Calcium ions on Struvite Crystallization Elimination of phosphates from an aqueous solution comprising synthetic wastewater and landfill leachate was carried out by Hassidou et al. [5] in Tunisia. The leachate was obtained from the Jbel Chakir landfill site, the biggest landfill in Tunisia that held domestic solid wastes from the greater Tunis region. Certain ions such as calcium were thought to have a significant influence on the process of struvite crystallization. The particular aspects that encountered the effect of calcium ions were the amount, shape and clarity of the commodity recovered. Therefore, the researchers aimed at investigating the process of calcium carbonate precipitation during the elimination of phosphates with struvite removal. The technique also intended to improve the cost efficiency of the method by shortening the continuous aeration time and determining the precise nucleation time for struvite. Condensed air was used to purge dissolved carbon dioxide gas from the solution thereby increasing the pH of the solution. Precipitation occurred when the conditions changed from acidic to alkaline. Figure 1: Changes in pH with time during phosphate removal with struvite formation and controlled degassing [5]. Three distinct steps were witnessed as depicted by figure 1. In the first phase, the pH rose rapidly due to the elimin ation of carbon dioxide, which lowered the acid content of the solution. A peak was attained at a pH of 8.3 followed by a steady decline (the second phase). The decline was attributed to the nucleation and enlargement of the struvite crystal. The last phase revealed a steady increase in the pH, which was because of an increase in the carbon dioxide escaping from the system. The maximum pH (8.3) was attained after seventeen minutes implying that the nucleation time and pH for struvite formation were 8.3 and 17 minutes respectively. The amount of soluble phosphorus that was present in the wastewater after 60 minutes was 1.5 millimoles and 2.6 millimoles in the leachate. Hassidou et al. [5] indicated that at the end of the run, the efficiency of phosphate removal was 61.19% in the leachate and 77.61 in synthetic wastewater. Those findings implied that impurities such as calcium ions interfered with the process of crystallization and the efficiency of the technique. Removal of Phosphate s from an Aqueous Solution from Animal Manure by Struvite Crystallization alongside Carbon Dioxide Degassing Zhang et al. [6] used a continuous U-shaped reactor in the removal of phosphates from an aqueous solution from animal manure. The reactor comprised three distinct zones namely the aeration crystallization region (1 dm3), the region of crystal growth (0.5 dm3) and the zone of crystal and supernatant separation (0.5 dm3). Figure 2: Continuous U-shaped reactor arrangement [6]. It was realized that the amount of phosphates obtained was lower (between 47% and 53%) when struvite was allowed to form spontaneously than when the wastewater was supplemented with magnesium (as MgCl2 at 57.5 mg per liter). The addition of magnesium yielded a phosphate recovery ratio of between 80% and 86%. Additionally, preformed struvite was the most effective seeding material compared to sand and stainless steel. These outcomes differed from the efficiency obtained by Hassidou et al. [5] in a similar degassing technique. However, the pH at which nucleation began was almost similar in both studies. A water extraction test revealed that the struvite obtained was very useful as a slow release fertilizer. Struvite Precipitation in Combination with Reverse Osmosis Sewage sludge was mostly treated by anaerobic digestion with biogas production. Karabegovic et al. [7] reported that the process of anaerobic digestion reduced the organic content of wastewater since the microbes involved often consumed macromolecules such as fats, proteins and carbohydrates. Approximately an eighth of the organic matter in wastewater was used up while a tenth was transformed into composite organic substances. The residual tenth was part of the post-digestion liquor and was accountable for the high chemical oxygen demand (COD) of such fluids. Reverse osmosis (RO) was an effective technique of ridding the post-digestion liquor of contaminants. However, its efficacy was marred by high concentrations of ammoni um ions that could not be contained by the RO membranes. Bohdziewicz and Kuglarz [8] used struvite accumulation as a pretreatment technique of post-digestion liquors prior to reverse osmosis. Struvite was removed at a temperature of 20 oC and pH of between 9.0 and 9.5, which was significantly higher than the pH used by Hassidou et al. [5], Zhang et al. [6] and Harrison et al. [9]. It was realized that the amount of ammonium ions surpassed the stoichiometric ratio required to form struvite while the concentrations of phosphate and magnesium were less than the needed amount. Therefore, Bohdziewicz and Kuglarz [8] used phosphoric acid as well as a combination of the oxide and chloride of magnesium to amend the concentrations of magnesium and phosphate ions before the crystallization. It was reported that the technique achieved a phosphate removal rate of 87% to 92% before the adjustment of the concentrations of magnesium and phosphorus. Conversely, a phosphate removal rate of between 9 8% and 99% was attained when the ratios were adjusted. The removal of COD was also affected by the form in which the magnesium ions were added. Magnesium in the form of MgO led to a higher COD removal value than the addition of Mg as MgCl2. That observation was attributed to the traits of Mg(OH)2 that led to the precipitation of dissolved organic compounds alongside struvite. The efficiency of reverse osmosis was higher following the pretreatment of post-digestion liquor by struvite removal. Figure 3: The effect of pretreatment of post-digestion liquor by struvite precipitation on reverse osmosis [8]. Continuous Reaction Crystallization of Struvite from an Aqueous Solution Containing Phosphate (V) and Nitrate (V) ions Hutnik et al. [10] investigated the removal of phosphates from solutions that contained between 0.2% and 1% of phosphates by mass and 0.0443% to 0.866% nitrate (V) ions by mass. The processes were performed in two different phases. A continuous struvite reaction cryst allization unit was operated with the concentrations of magnesium, phosphate and ammonium at stoichiometric proportions. The second phase involved a DT MSMPR crystallizer (Draft Tube, Mixed Suspension Mixed Product Removal) where magnesium ions were in excess by approximately 20%. The temperatures in both phases were 25 oC and the pH ranged from 9 to 11. In addition, crystallization was allowed to take place for durations between 15 minutes and one hour. Hutnik et al. [10] investigated the effect of pH and the ions on the quality of struvite crystals formed. Hutnik et al. [10] observed that as the concentration of nitrates in the aqueous solution was increased, the average size of the crystals decreased by approximately ca. 29%. In addition, there was no uniformity in the size of crystals formed. On the other hand, Hutnik et al. [10] realized that elevating the pH had a negative effect on the quality of struvite crystals formed as smaller irregular crystals were formed. It was also noted that a reduction in the concentration of phosphate ions caused an increase in the crystal size by about ca. 23%. Longer reaction times led to an increase in the size and uniformity of the crystals formed. Moreover, the elevation of the concentration of magnesium ions was found to favor struvite crystallization leading to the formation of large tubular crystals. Figure 4: Scanning electron microscope images of the crystals obtained from crystallization using 0.0886% of nitrates (a) and 0.443% of nitrates (b) [10]. Figure 5: Scanning electron microscope images showing the effect of pH and reaction time on the size of crystal formed. In (a), the conditions were pH 11 and a reaction time of 15 minutes, whereas in (b) the conditions were pH 9 and a reaction time of one hour. The concentration of nitrate (V) ions in both cases was 0.0886% [10]. Struvite Crystallization from Diluted Aqueous Solution of Phosphate (V) Ions in the Presence of Magnesium Ions Excess Kozik et al. [11] in vestigated the crystallization of struvite from an aqueous solution containing phosphate (V) ions at a concentration of 0.2 % by weight. A DT MSMPR type crystallizer was used at a temperature of 25 oC and a pH range from 8.5 to 10. Additionally, the concentration of magnesium ions surpassed the stoichiometric ratio for struvite formation by a fifth. The average residence time for the crystallization process was between 900 and 3600 seconds. Kozik et al. [11] reported that crystals of average sizes ranging from ca. 19 to ca. 3 were obtained. A pH of 8.5 for 3600 seconds yielded decently sized crystals with satisfactory homogeneity. Kozik et al. [11] reported that at those conditions, the rate of linear growth of the crystals was between 3.62 x 10-9 and 1.68 x 10-8 metres per second. The presence of excess magnesium ions during struvite crystallization improved the production of struvite. However, the quality of the crystals was somehow affected. Kozik et al. [11] reported that the co ncentration of phosphate ions in the original aqueous solution decreased from 0.2% by weight to 9-92 milligrams per kilogram of the aqueous solution implying that the process was effective in recovering phosphates from aqueous solutions. It was noted that the optimum crystallization was obtained at the same reaction conditions as those reported by Hutnik et al. [10]. Phosphate Removal by Struvite Recovery in a Microbial Electrolysis Cell Cusick and Logan reported that microbial electrolysis cells offered the most cost-effective way of struvite recovery from aqueous solutions [12]. Uninterrupted chemical supplementation and blower operations significantly increased the cost of struvite by approximately 400 dollars per ton of struvite recovered compared to about 50 dollars spent on production of phosphorus from phosphate deposits. The quantities of chemicals added contributed to about 97% of the total amount spent on struvite precipitation. Therefore, it was necessary to minimize the costs of struvite formation from wastewater to make the entire process economically viable. Microbial electrolysis cells simultaneously produced hydrogen gas and removed phosphates from wastewater without the need for chemical addition and large energy inputs. The two types of cathodes used by Cusick and Logan were mesh and plate cathodes both made of stainless steel. Struvite recovery rates ranging from 20% to 40% were obtained, which were significantly lower than the values reported by Hassidou et al. [5], Zhang et al. [6] and Harrison et al. [9]. However, the process was more efficient (73%) than the conventional struvite recovery procedures in terms of energy requirements. It was realized that net cathodes were more efficient than the flat cathodes. It was concluded that additional research and optimization of the microbial electrochemical cells could save a substantial amount of energy during phosphate removal from wastewater. The Effect of Temperature, Reaction Time, and pH on the Amount of Phosphates Recovered as Struvite from Aqueous Solutions Ahmad and Idris [13] investigated the parameters that affected the process of struvite crystallization during phosphate removal. Aerobically digested wastewater was used in the investigation. Temperatures higher than 100 oC were applied to sludge following the treatment of wastewater. The amount of soluble phosphates was quantified in the wastewater as the heating temperature rose. Ahmad and Idris realized that the amount of phosphorus released into the wastewater increased with an increase in temperature and time of heating [13]. Figure 6: The influence of temperature on the quantities of dissolved phosphorus [13]. The concentration of dissolved and suspended phosphorus was 3.4 and 4.6 mg per liter prior to heating. However, the highest amount of liberated phosphorus was attained following heating at 175 oC for 100 minutes. The release of phosphorus with an increase in temperature was attributed to microbial ce lls whose membranes were disrupted following heating leading to the release of phosphorus. It was also realized that more phosphorus was released into the wastewater at low pH. Ahmad and Idris attained the highest levels of phosphorus release were attained at pH of 2 (48.9 milligrams per liter) and pH of 4 (48.6 milligrams per liter) [13]. The reason for that occurrence was that the majority of phosphates in wastewater sludge were organophosphates that were easily liberated by heating. Figure 7: Influence of pH on the release of phosphorus [13]. A separate investigation by Yariv and Holger investigated the prospects of raising the pH of aqueous solutions by exclusion of carbon dioxide and using gases such as plain air, oxygen and nitrogen to replace the vacuum left by CO2 [14]. The pH of the solution was monitored by a computer-regulated setup. Yariv and Holger [14] observed that plain air eliminated carbon dioxide leading to an increase in pH up to 8.53. Pure nitrogen, conversely, elevated the pH of the solution to 10.4 after one day. A separate trial where carbon dioxide was eliminated by precipitation as calcium carbonate increased the pH to about 9.4. All these pH values were within the optimum range required for struvite precipitation. Yariv and Holger [14] concluded that it was possible to reduce the costs of struvite precipitation by using air instead of chemicals to raise the pH of aqueous solutions. The Effect of Copper (II) Ions on the Quality of Struvite Produced It was thought that impurities affected the crystallization of struvite. Therefore, Hutnik et al. [15] sought to determine the effect of copper ions in aqueous solutions on struvite crystallization. An aqueous solution containing 1 to 2% of phosphate ions by mass and 0.5 milligrams of copper ions per kilogram of solution was used. Struvite crystallization was performed at stoichiometric conditions and magnesium ion excess. Hutnik et al. [15] noted that the presence of copper ions in the re actor increased the size of struvite crystals by 6% at stoichiometric conditions. However, lowering the phosphate concentration and increasing the quantity of magnesium yielded 9% to 13% larger crystals. Table 1: The effect of copper ions of struvite crystals at a temperature of 25 oC, pH 9 and mean residence time of 900 seconds [15]. Figure 8: The morphology of struvite crystals produced in the presence of copper (II) ions [15]. Analysis of the final product revealed the presence of copper (II) hydroxide at concentrations ranging from 6 to 90 milligrams per kilogram. It was concluded that the presence of copper ions promoted the formation of tubular struvite crystals. Struvite Formation from Human Urine Etter et al. [16] investigated the possibility of using human urine to concentrate phosphates for agricultural use. Urine used in the study was collected from Siddhipur village in Nepal because of the common practice of the creation of urine separation pits in the community. Magne sium oxide from a local magnesite was used as a magnesium source. Etter et al. [16] reported that more than 90% of phosphates was recovered from the reactor with an external filtration unit with minimal usage of magnesium oxide (1.1 moles of magnesium per 1 mole of phosphate) in one hour. Rough nylon filters were used in the filtration unit. Conversely, a separate sedimentation setup yielded only 40% of phosphates. Etter et al. [16] concluded that large volumes of urine were needed for the process to yield substantial volumes of struvite. The designing of struvite crystallization machinery must put into consideration factors such as the growth rate of the struvite crystals and the supersaturation of the aqueous solutions. For this reason, several studies have been carried out to model the process of struvite recovery. Harrison et al. [9] focused their attention on the dynamics of struvite crystallization with the aid of a computer package referred to as MINTEQA2. Harrison et al. [9] reported that the software determined struvite as being insoluble at moderately alkaline pH and that temperature did not have a substantial effect on the solubility of struvite. Those findings implied that optimum crystallization was supposed to take place at moderately basic conditions. The formation of large crystals implied that more of the dissolved struvite was incorporated into the crystals hence translating to higher struvite recovery rates from the solutions. However, despite those observations, various studies continued to obtain varying quantities of struvite from wastewater and other aqueous solutions. For example, Zhang et al. [6] reported improved efficiencies when magnesium was supplemented (80-86% recovery rates) compared to 47-53% recovery rates when crystallization was allowed to take place spontaneously without magnesium supplementation. In both instances, Zhang et al. [6] used temperatures of 25 oC and the pH range described by Harrison et al. [9]. Conversely, Ha ssidou et al. [5] obtained phosphate removal rates of 61.19% from leachate and 77.61% from synthetic wastewater. Otter et al. [16] were able to recover up to 90% phosphates from human urine. These variations in struvite recovery rates suggested that there were certain aspects in the compositions of the aqueous solutions that altered the struvite recovery rates. The contentious issue, therefore, became the optimum conditions for the most efficient removal of phosphates from aqueous solutions. It was hypothesized that factors other than temperature and pH affected the kinetics and efficacy of struvite crystallization. Therefore, there was a need to ascertain the precise factors and their consequences on struvite crystallization. Hutnik et al. [10], Kozik et al., [11] and Hutnik et al. [15] looked at the efficiency of the formation of struvite crystals under varying concentrations of various ions such as nitrates phosphates and magnesium. Hutnik et al. [10] and Kozik et al. [11] noted that better crystallization rates were obtained with magnesium concentrations that surpassed the stoichiometric concentrations in struvite. Zhang et al. [6] observed that higher struvite yields corresponding to higher phosphate removal rates were attained with magnesium supplementation. These observations deduced that in spite of struvite formation occurring at the stoichiometric concentrations of magnesium, ammonium and phosphates, an excess of magnesium ions enhanced the process of crystallization. The effect of interfering ions on struvite crystallization was also investigated by Ahmad and Idris [13] and Hutnik et al. [15]. Ahmad and Idris [13] observed that calcium ions acted as impurities and lowered struvite crystallization rates. These observations suggested that the presence of other cations in aqueous solutions was likely to lower struvite crystallization. On the other hand, contrary to the expectations, Hutnik et al. [15] realized that copper ions augmented struvite crysta llization and even led to the formation of large crystal sizes. Conclusion From all the papers reviewed in this research, it was evident that struvite formation occurred at alkaline pH between 8 and 10 and temperatures between 20 oC and 25 oC. The optimum pH was attained by the removal of carbon dioxide gas. The resultant struvite was useful as a slow release manure, which did not require additional processing apart from washing and drying. The conditions in the reacting vessels were adjusted to optimize struvite formation, for example, through the addition of magnesium ions to ensure that the reactants were in the right proportions according to the molecular formula of struvite. It was noted that adding magnesium as magnesium oxide led to lower COD values than when it was added as magnesium chloride. However, Capdevielle et al. [2] and Capdevielle et al. [17] noted that magnesium oxide significantly increased the amount of struvite recovered. Overall, excessive magnesium ions led t o better rates of struvite crystallization. The presence of interfering cations such as calcium ions lowered the efficacy of crystallization while copper ions augmented crystallization. From these findings, it appeared as though there could be additional undiscovered factors that affected struvite crystallization. Therefore, further investigations could be carried out to establish the additional factors that influenced phosphate removal from aqueous solutions through struvite crystallization. Struvite precipitation was also used as a pretreatment technique to improve the efficiency of other purification methods such as reverse osmosis. Therefore, this research concluded that the removal of phosphate from aqueous solutions via struvite formation was an efficient method of preventing the pollution of water bodies and recycling phosphates. References [1] K. S. Le Corre, E. Valsami-Jones, P. Hobbs, and S. A. Parsons, â€Å"Phosphorus Recovery from Wastewater by Struvite Crystallization : A Review.† Critical Reviews in Environmental Science and Technology, vol. 39 no. 2009, pp. 433–477, May 2009. [2] A. Capdevielle, E. Sà ½korov, F. Bà ©line, and M. Daumer, â€Å"Kinetics of struvite precipitation in synthetic biologically treated swine wastewaters.† Environmental Technology, vol. 35, no. 10, pp. 1250-1260, Jan. 2014. [3] US EPA. â€Å"Nutrient pollution.† Internet: https://www.epa.gov/nutrientpollution/issue, Mar. 16 2014 [May 18 2014]. [4] R. Mylavarapu. â€Å"Impact of phosphorus on water quality.† Internet: http://edis.ifas.ufl.edu/ss490, Apr. 14 2014 [May 18 2014]. [5] S. Hassidou, T. Ismail and B. A. Mohamed, â€Å"Phosphorous removal from Tunisian landfill leachate through struvite precipitation under controlled degassing technique.† Desalination and Water Treatment, vol. 21, no. 2010, pp. 295–302, Sep. 2010. [6] T. Zhang, P. Li, C. Fang, and R. Jiang, â€Å"Phosphate recovery from animal manure wastewater b y struvite crystallization and CO2 degasification reactor.† Ecological Chemical Engineering Science, vol. 21, no. 1, pp. 89-99, 2014. [7] L. Karabegovic, M. Uldal, A. Werker and F. Morgan-Sagastume, â€Å"Phosphorus recovery potential from a waste stream with high organic and nutrient contents via struvite precipitation,† Environmental Technology, vol. 34, no. 7, pp. 871-883, Aug. 2013. [8] J. Bohdziewicz and M. Kuglarz, â€Å"Treatment of post-digestion liquors with the application of struvite precipitation and reverse osmosis.† Desalination and Water Treatment, vol. 5, no. 2013, pp. 366–373, Jan. 2013. [9] M. L. Harrison, M. R. Johns, E. T. White, and C. M. Mehta, â€Å"Growth rate kinetics for struvite crystallization.† Chemical Engineering Transactions, vol. 25, no. 2011, pp. 309-314, 2011. [10] N. Hutnik, B. Wierzbowska, K. Piotrowski, and A. Matynia. â€Å"Continuous reaction crystallization of struvite from solution containing phosphate (V) and nitrate (V) ions.† The Online Journal of Science and Technology, vol. 3, no. 2, pp. 68-66, Apr. 2013. [11] A. Kozik, H. Nina, P. Krzysztof, and M. Andrzej. â€Å"Continuous reaction crystallization of struvite from diluted aqueous solution of phosphate(V) ions in the presence of magnesium ions excess.† Chemical Engineering Research Design, vol. 92, no. 3, pp. 481-489, Mar. 2014. [12] R. D. Cusick and B. E. Logan, â€Å"Phosphate recovery as struvite within a single chamber microbial electrolysis cell.† Bioresource Technology, vol. 107, no. 2012, pp. 110-115, 2012. [13] A. A. Ahmad and A. Idris, â€Å"Release and recovery of phosphorus from wastewater treatment sludge via struvite precipitation.† Desalination and Water Treatment, vol. 2013, pp. 1-8, Jun. 2013. [14] C. Yariv and K. Holger, â€Å"Increasing the pH of wastewater to high levels with different gases- CO2 stripping.† Water, Air and Soil Pollution, vol. 159, no.2004, pp. 265-275, Jun. 2004. [15] N. Hutnik, B. Wierzbowska, K. Piotrowski, and A. Matynia. â€Å"Effect of copper (II) ions on quality of struvite produced in continuous reaction crystallization process at the magnesium ions excess.† Advances in Chemical Engineering and Science, vol. 2013, no. 3, pp. 1-6, May. 2013. [16] B. Etter, E. Tilley, R. Khadka, and K. M. Udert â€Å"Low-cost struvite production using source-separated urine in Nepal.† Water Research, vol. 45, no. 2, pp. 852-862, Jan. 2011. [17] A. Capdevielle, E. Sykorov, B. Biscans, F. Bà ©line, and M. Daumer, â€Å"Optimization of struvite precipitation in synthetic biologically treated swine wastewater- Determination of the optimal process parameters.† Journal of Hazardous Materials, vol. 244-245, no. 2013, pp. 357-369, 2013.

NAFTA effects on Mexico essays

NAFTA effects on Mexico essays The North American Free Trade Agreement (NAFTA) has been implemented with the intentions to eventually open the borders between Canada, the United States, and Mexico. This paper will only deal with the effects of the trade agreement on Mexico. This paper will attempt to show that the implementation of NAFTA and its guidelines have increased flows of U.S. foreign direct investment into the country of Mexico, and subsequently improved Mexico s economy. With the United States, Mexico, and Canada signing the North American Free Trade Agreement (NAFTA), the ground rules are set into place to allow Mexico to prosper from inflows of Foreign Direct Investment (FDI). The rules of NAFTA will protect the investments of foreign investors by locking Mexico into NAFTA regulations on direct investing (Krueger 2000). Domestic U.S. firms will be eager to invest in Mexico for a competitive advantage made possible by the NAFTA agreement and Mexicos economic conditions. This paper will discuss how NAFTA helped secure investment from the U.S. into Mexico. Additionally, why domestic U.S. firms would consider FDI into Mexico, and how U.S. FDI may have helped Mexico through its economic crisis in 1995. In order for a domestic firm to undertake foreign direct investment (FDI), they must first be able to compete effectively in their home market. Once the firm obtains a domestic competitive advantage that is strong enough to sustain and compensate for investment damages incurred by investing abroad, the firm can consider FDI (textbook). Once a firm has decided it is ready to directly invest in a foreign market, the firm must decide where to invest. The decision to invest is made by locating markets that may have a comparative advantage, or a market imperfection that would allow the investor to prosper by entering the market. For example, motivating factors of investment include: profits attainable through lower tax rates, more le...