Fate and removal of persistent pharmaceuticals during advanced sludge digestion processes

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Municipalities and industries rely on biological treatment processes to treat organic pollutants in wastewater. However, one of the drawbacks of biological wastewater treatment is high residual sludge generation. Treatment and disposal of residual sludge is a bottleneck in wastewater treatment plant operation in both developing and industrial countries due to more stringent quality requirements for landfilling, ocean disposal, and incineration. It is only in recent years that more sludge is beneficially used as soil amendment after conventional or advanced sludge treatment processes (i.e. composting, aerobic or anaerobic digestion). Although land application of biosolids (treated wastewater sludge) has been accepted as a cost-effective waste disposal method that provides other benefits (i.e. recycling nutrients to improve soil quality), it can carry environmental risks. Odours, pathogens, heavy metals and other anthropogenic micropollutants, such as estrogenic hormones, pharmaceuticals and personal care products, brominated flame retardants, and musks are major contaminants with emerging concern creating public opposition to land application of biosolids. The proposed program will address gaps in knowledge related to the impact of conventional and advanced biological sludge treatment technologies on the fate and removal of six persistent pharmaceuticals; one antibiotic (Azithromycin), one lipid regulator (Bezafibrate), one anti-epileptic (Carbamazepine), and three analgesics/anti-inflammatory agents (Diclofenac, Ibuprofen and Mefenamic acid). These compounds have been selected due to their slowly-biodegradable nature, vast usage, toxicity and bioaccumulation potential. Furthermore, except Azithromycin, they are listed as endocrine disrupting compounds that can interfere with the normal function of hormones when discharged to the environment. In the short term, the project will examine the performance of various conventional and cutting-edge sludge digestion configurations and operational strategies to enhance biogas production, to minimize the volume of residual biosolids and to enhance the biodegradation of the selected pharmaceuticals at the UBC Bioreactor Technology Laboratory. In the long term, the sludge treatment technology to be developed will allow for the production of safer and publically more acceptable biosolids. Other benefits will include recommendations on ways to improve conventional biosolids treatment processes to mitigate the release/impact of micropollutants and the training of highly qualified personnel in an emerging area. Our municipal partners will obtain valuable information on the efficiency of their sludge treatment and advanced sludge digestion processes. Health Canada and the BC Ministry of Environment will obtain additional knowledge on the fate of their prioritized list of emerging compounds in biosolids.**