Simultaneous organic nitrogen and sulfate removal in an anaerobic GAC fluidised bed reactor

Abstract

A granular activated carbon (GAC) anaerobic fluidised bed reactor treating vinasse from an ethanol distillery of sugar beet molasses was operated for 250 days under three different organic loading rates. The reactor showed good performance in terms of organic matter removal and methane production but an anomalous behaviour in terms of unusual high concentrations of molecular nitrogen and low concentration of hydrogen sulphide in the biogas. The analysis of the different nitrogenous and sulphur compounds and the mass balances of these species in the liquid and gas phases clearly indicated an uncommon evolution of nitrogen and sulphur in the reactor. Up to 55% of the TKN and up to 80% of the sulphur disappear in the liquid phase. This is the opposite to any previously reported results in the bibliography. The new postulated anaerobic process of ammonia and sulphate removal seems to follow the mechanism: SO4 = +2 NH4+-->S + N2 + 4H2O (delta G degree = -47.8 kJ/mol).

Comparative anaerobic treatment of wastewater from pharmaceutical, brewery, paper and amino acid producing industries

“…Van Houten et al [25] demonstrated that concentrations below 450 mgl À1 of sulfate did not inhibit sulfate-reducing activity. There is a possibility of that the sulfide from sulfate-reducing microorganisms is utilized by nitrate-reducing microorganisms [6]. In fact, the sulfide in the medium was detected in low concentrations.…”

S115 Characteristics of Sulfate Reduction–Ammonia Oxidation under Anaerobic Conditions

“…Fdz-Polanco et al [10,15] reported that ammonia and sulfate could be removed synchronously in an anaerobic fluidized bed reactor (AFBR) filled with granular activated carbon (GAC) when treating industrial wastewater that was rich in organic matter, nitrogen and sulfate. Such a procedure was named sulfate reduction and ammonia oxidation (SURAMOX), main chemical reaction of which is shown in Equation (2) …”

“…In ANAMMOX reaction, NH 4 + -(3) N/NO 2 --N conversion ratio is 1.00:1.32, with portion of NO 2 --N converted to NO 3 --N to provide electron for the reduction of CO 2 [28]. It is, commonly, considered that the production of NO 3 --N is due to ANAMMOX in sulfate reduction-ammonia oxidation [10,[15][16][17][18]29].…”

Tratamento de vinhaça em reator anaeróbio operado em batelada seqüencial contendo biomassa imobilizada sob condições termofílicas e mesofílicas

“…Vários autores avaliaram o reator UASB para tratamento anaeróbio termofílico da vinhaça por apresentar melhor desempenho (WIEGANT et al, 1986, SOUZA et al, 1992, VLISSIDIS & ZOUBOULIS, 1993, DRIESSEN et al, 1994e HARADA et al, 1996. Mas, outras configurações de reatores já foram estudadas como alternativas para tratamento da vinhaça (BALAGUER et al, 1997, FERNANDEZ et al, 2001, TELH, 2001e RUIZ et al, 2001. Alguns dos estudos mais significativos sobre o tratamento anaeróbio de vinhaça são apresentados na Tabela 3.5 com relação às taxas máximas obtidas de carregamento orgânico.…”

“…Harada et al (1996) adicionaram meio de nutrientes e de elementos traço de acordo com Wiegant & Lettinga (1985) com suplementação de bicarbonato de sódio como tampão na concentração de 5g/L para manter o pH ao redor de 7,3 ao longo de toda fase experimental. Fdz-Polanco et al (2001) utilizaram reator anaeróbio de leito fluidificado internamente, com volume de 1,5 litros, preenchido com carvão ativado granulado, com partículas de diâmetro médio entre 0,42 e 0,85 mm com expansão de leito de 30%. O inóculo usado foi lodo anaeróbio de um reator de contato de indústria de levedura e adição de diferentes doses de sulfato e amônio.…”