Effects of carbon sources on phosphorus speciation transformation process, characteristics of extracellular polymeric substances, and microecology in anaerobic systems

Abstract

The effects of different carbon sources on the transformation process of the form of phosphorus and microecology were examined in an anaerobic system using glucose and L-malic acid as carbon sources. Results showed that for these two carbon sources (glucose and L-malic acid), the average removal efficiencies of chemical oxygen demand by up-flow anaerobic sludge bed reactors were 97.16 % and 88.63 %, and the average removal efficiencies of total phosphorus were 11.38 % and 5.68 %, respectively. The average concentrations of phosphine in anaerobic reactors using glucose and L-malic acid as carbon sources were 160.73 mg/m3 and 90.80 mg/m3 over days 24–40, respectively. When glucose was used as carbon source, the proportions of biologically available phosphorus (i.e., the sum of non-apatite inorganic phosphorus and organic phosphorus content) within total phosphorus in sludge on days 0, 20, and 40 were 76.22 %, 77.90 %, and 85.04 %, respectively. Glucose could better promote the enhancement of dehydrogenase activity than L-malic acid. The carbon source affected the activity of alkaline phosphatase, and the enzyme activity was stronger when glucose was used as carbon source. Kyoto Encyclopedia of Genes and Genomes functional analysis showed that amino acid metabolism and carbohydrate metabolism dominated. On days 0, 30 and 60, the relative abundances of carbohydrate metabolism in microorganisms using glucose as carbon source were 0.26 %, 0.36 %, and 0.34 % higher than those with L-malic acid as carbon source, respectively.