Made available in DSpace on 2014-12-17T15:03:30Z (GMT). No. of bitstreams: 1 LilianeFGL_DISSERT.pdf: 931554 bytes, checksum: 0bbe7c36b3d8afca89214b8b2d97bd81 (MD5) Previous issue date: 2012-12-07 / This study investigated the influence of the molar ratio, the phosphorus initial concentration, the mixture gradient, mixing time, pH and the secondary nucleation on struvite s crystallization in synthetic water in batch reactors. The study was divided into two stages. The first investigated struvite s crystallization at different Mg:N:P molar ratios and at different initial concentrations of magnesium, nitrogen and phosphorus. It was also evaluated the importance of secondary nucleation on the struvite s crystallization. In the second, five parameters were tested to evaluate their influence on the struvite s crystallization, which were: Mg:N:P molar ratio, initial concentration of phosphate, mixing time, mixture gradient and pH. The best conditions for struvite s crystallization were: Mg:N:P = 1,3:1:1 molar ratio; mixture gradient = 60 rpm, pH = 10.0, mixing time = 5 minutes and high initial concentrations of the constituent ions of struvite. Furthermore, the use of struvite crystals as seed influenced positively on the struvite s crystallization / O presente estudo investigou a influ?ncia da raz?o molar, da concentra??o inicial de f?sforo, do gradiente de mistura, do tempo de mistura, do pH e da nuclea??o secund?ria na cristaliza??o de estruvita em ?gua sint?tica, em reatores em batelada. A pesquisa foi dividida em duas etapas. A primeira investigou a cristaliza??o da estruvita em ?gua sint?tica em diferentes raz?es molares Mg:N:P e concentra??es iniciais de magn?sio, nitrog?nio e f?sforo, sendo tamb?m avaliada a import?ncia da nuclea??o secund?ria na cristaliza??o da estruvita. Na segunda etapa, cinco par?metros foram testados para avaliar a influ?ncia destes na cristaliza??o da estruvita, quais sejam: raz?o molar Mg:N:P, concentra??o inicial de f?sforo, gradiente de mistura, tempo de mistura e pH. As melhores condi??es observadas para a cristaliza??o de estruvita foram: raz?o molar Mg:N:P = 1,3:1:1; gradiente de mistura = 60 rpm; pH = 10,0; tempo de mistura = 5 minutos e elevadas concentra??es iniciais dos ?ons constituintes da estruvita. Al?m disso, a utiliza??o de cristais de estruvita como semente influenciou positivamente na cristaliza??o da estruvita