Salah Din Mahmud Hasan

Influência de nitrogênio amoniacal e vazão de ar no processo de nitrificação, etapa de tratamento de efluente de abatedouro de peixe

The fish slaughterhouse effluent presents high levels of nitrogen, one of the major causes of eutrophication in water bodies. Nitrogen removal can be accomplished in two separate stages: Nitrification and Denitrification. This experiment aimed to test the influence of air flow (values between 1 and 3 L min-1) and ammonia nitrogen concentration (between 40 and 100 mg L-1) in the nitrification process. A 2.5 L volume sequencing batch reactor with immobilized biomass was operated as central rotational composed design, where the evaluated results were conversion of ammonia nitrogen to nitrate in percentage and nitrite accumulation in percentage. The results with confidence interval of 95% showed that the increase of both variables resulted in the significant reduction of the percentage of nitrogen conversion to nitrate. The nitrite accumulation percentage significantly increased with the ammonia nitrogen increase, although it was not observed significant influence of air flow. During the experiment the best condition found for the equilibrium of the reactions was 70 mg L-1 of ammonia nitrogen and air flow of 2 L min-1.

Tratamento de efluente de abatedouro de tilápia com adição de manipueira na fase anóxica

The objective of this work was to evaluate the denitrification of tilapia slaughterhouse wastewater, in a batch reactor. For this, it was evaluated the wastewater from a cassava processing industry (manipueira) as a carbon source. It was also evaluated the shaking conditions of the process. The experiments were carried out in laboratory series, where five shaking levels were tested (20; 32; 60; 88 e 100 rpm) as well as five COD/N ratio levels (0.1; 1.0; 3.2; 5.4 and 6.3), forming a planning as a Central Composite Rotational Design (CCRD), with four essays in levels +1 and - 1; four essays on the axial points levels (-1.414 and +1.414) and one more triplicate in the central point (0), which meant eleven essays. The denitrification performance through the nitrate removal (%) and nitrite removal (%) were evaluated. During this process, temperature (oC), pH and alkalinity (mgCaCO3.L-1) were also observed. The results showed that the COD/N ratio had significant influence, with a 95 % of confidence interval, on the process of nitrate and nitrite removal, with a great operation range, from 3.2 to 5.4, whose nitrogen removal efficiencies were 100 %.

Nitrificação de efluente de abatedouro de tilápia em função da aeração e tempo de reação

The occurrence of composts of nitrogen above the legal limits has been causing serious pollution problems in water receptor bodies. The biological process for removal of these substances commonly found in the ammoniacal nitrogen form is known as nitrification. The present study had as its objective the evaluation of the effects of the reaction time (TR) and of the aeration on the removal efficiency of the ammoniacal nitrogen and on the conversion of the ammoniacal nitrogen to nitrate in a nitrification process of the tilapia slaughterhouse effluent in sequential batch reactor with biofilm. The experiment was performed using two reaction times (6 and 12 h) and two levels of air flow (3 and 6 L min-1), four treatments, starting from the combination of these two variables, were evaluated in an experimental planning of the factorial 22 type: being: T4 (QAr = 3 L min-1 and TR = 6); T2 (QAr = 6 L min-1 and TR = 6), T3 (QAr = 3 L min-1 and TR = 12) and T1 (QAr = 6 L min-1 and TR = 12), and four repetitions. The most significant results were obtained for treatment T4, where the efficiency for conversion of the ammoniacal nitrogen to nitrate obtained was 57.27 ± 27.05 and removal of the ammoniacal nitrogen was 81.90% ± 3.80.

Study of the growth of A. casiellus in conventional soybean meal for enzyme production

O farelo de soja e um dos principais residuos da agroindustria brasileira, tendo em vista a grande producao nacional do grao. Este subproduto apresenta caracteristicas que tornam interessante sua utilizacao como substrato nos processos de fermentacao em estado solido (FES). Apesar de nao ser tao utilizado industrialmente quanto a fermentacao submersa (FSm), pode ser uma alternativa viavel, pois apresentada resultados superiores de produtividade, principalmente no cultivo de fungos filamentosos e na producao de enzimas. Assim, o presente trabalhou teve como objetivo a producao das enzimas protease, amilase e invertase por FES, utilizando farelo de soja convencional e o fungo A. casiellus . Foram avaliadas a variacao do pH e fontes de nutrientes, otimizacao dos parâmetros da FES por meio de planejamentos experimentais e construcao de curvas de crescimento do fungo. Na otimizacao do processo de producao para a invertase, os melhores valores de atividade enzimatica especifica (AEesp) foram obtidos em pH neutro (6,7) e 3% de fonte adicional de nitrogenio ao meio fermentativo, com umidade inicial do meio de 50% e temperatura de 28oC. O melhor resultado de atividade para a protease foi obtido na avaliacao das fontes de nutrientes do meio, com a utilizacao de 2% de fonte de carbono e nitrogenio e 2% de fontes minerais. Ja a amilase nao apresentou resultados significativos para as variaveis empregadas. Palavras-chave: FES, farelo de soja, A. casiellus.