Complete and stable enhanced biological phosphorus removal at 30 °C using glutamate and acetate as alternating carbon sources.

Most enhanced biological phosphorus removal (EBPR) research has focused on volatile fatty acids (VFAs) as carbon sources and operating temperatures in temperate climates. Here we evaluate glutamate and acetate as alternate carbon sources in a laboratory-scale sequencing-batch reactor operated at 30 °C (tropical-climate wastewater temperature). Efficient EBPR was achieved for 140 days using a substrate supply scheme of two weeks of glutamate followed by one week of acetate. Candidatus Accumulibacter was the only known polyphosphate-accumulating organism during the period of good EBPR performance, reaching a relative abundance of 12.1 %. Higher phosphorus release and uptake were observed with acetate than with glutamate; yet both carbon sources supported complete phosphorus removal. The polyhydroxyalkanoate formation when glutamate was fed was only 12.5 % of that with acetate, suggesting that the amino acid was stored as an unidentified compound. This study provides evidence that amino acids in raw sewage and industrial effluents can supplement VFAs in full-scale EBPR.