Biological nutrient removal with limited organic matter using a novel anaerobic–anoxicoxic multi-phased activated sludge process

Abstract EN

-An anaerobic–anoxic/oxic (A2/O) multi-phased biological process called ‘‘phased isolation tank step feed technology (PITSF)’’ was developed to force the oscillation of organic and nutrient concentrations in process reactors.

PITSF can be operated safely with a limited carbon source in terms of low carbon requirements and aeration costs whereas NAR was achieved over 95% in the last aerobic zone through a combination of short HRT and low DO levels.

PCR assay was used for XAB quantification to correlate XAB numbers with nutrient removal.

PCR assays showed, high NAR was achieved at XAB population 5.2 · 108 cells/g MLVSS in response to complete and partial nitrification process.

It was exhibited that low DO with short HRT promoted XAB growth.