Biosolids & Odor
Under the biosolids theme, research for integrated biosolids management encompassing innovative technologies aimed at energy recovery, solids minimization, odour reduction, fertilizer production, and achievement of Class A sludge is being conducted. Presence of microppllutants such as pharmaceuticals and personal care products in trace concentrations in wastewater is a global concern. Many of them are hydrophobic and partition into biosolids and are poorly removed in anaerobic digestion. Combinations of advanced oxidation processes are being used to enhance anaerobic digestion of target endocrine disruptor compounds as well as improve pathogen reduction in biosolids for land application. Leaching of micropollutants from biosolids under various conditions, uptake of micropollutants, and their effects on plant growth are being studied under both controlled and field conditions.
Hydrogen peroxide (H2O2) can be produced using microbial fuel cells (MFCs), in which an electron donor (soluble COD in the sludge/wastewater) is oxidized by anode-respiring bacteria (ARB) releasing electrons that combine with an electron acceptor, typically dissolved oxygen, and forms H2O2 with the counter ions (ideally H+). Microbially produced H2O2 can be used to pretreat sludge prior to anaerobic digestion and the degradation of micropollutants and pathogen would be tracked in both pretreatment and subsequent anaerobic digestion units.
The capital costs associated with digester construction and nutrient recovery can be reduced significantly by incorporating membranes in anaerobic digesters; process optimization will be conducted for parameters such as sludge type, residence time, and membrane configurations. In addition, the potential for integration of AnMBRs digesting sludge with nutrient recovery technologies has yet to be evaluated.