嫌気好気汚泥における硫黄と鉄の生物的酸化還元およびりん放出の相互作用

抄録

Simultaneous sulfur and iron oxidation-reduction in anaerobic-oxic activated sludge were examined using activated sludge of a municipal wastewater treatment plants (WWTP) and two laboratory scale plants (AO) and (O). Batch experiments were carried out using artificial wastewater. For the WWTP sludge, the sulfate reducing rates increased with maximum released phosphate but did not show the same relationship with the AO and O sludge. Sulfate reduction rates tended to increase with sulfide oxidation rates for both wastewater treatment and laboratory scale sludge. Under oxic conditions, both sulfide and iron oxidation occurred simultaneously and iron was responsible for lowering sulfide oxidation rates. In anaerobic conditions, sulfate and iron reduction occurred simultaneously with sulfate inhibition by the iron bacteria. Phosphate release tended to increase with a decrease in iron reduction. The results from the electron flow and activity calculations suggested that although the sulfate reducing bacteria utilized more substrate electrons than iron reducing bacteria, the iron reducing activity was enough to cause inhibition of sulfate reduction.