Advanced Biosolid Digestion to Control Nutrient and Micropollutants Discharged from the Westside Regional Wastewater Treatment Plant

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Regional District Central Okanagan

Project Description:

The aim of this project has been to identify how biosolids digestion can be used to reduce nutrients and micropollutants in treated effluent discharged to Okanagan Lake from the Westside Regional Wastewater treatment plant. As well as to understand the transport and fate of micropollutants in land applied biosolids to ensure that these compounds do not enter Okanagan lake if bio solids are land applied in the region.

The micro pollutants of interest have been selected based upon compounds that have been shown to be commonly present in wastewater, are not effectively removed during wastewater treatment, and tend to be persistent and/or bio accumulative in the environment. These include two ubiquitous antimicrobials and five of their metabolites, along with a selection of common pharmaceuticals.

Development of extraction techniques for these compounds from various sample matrices (surface water, untreated wastewater, treated wastewater, wastewater sludge, digested sludge, sludge centrate, biosolids, struvite crystals, and river/lake sediment) have been completed. This process also included the development of instrumental analytical techniques for the detection and quantification of the aforementioned compounds, which has been completed and refined to detect these compounds down to extremely low levels.

The operational phase of the small anaerobic digesters (ADs) has recently been completed. This first stage explored the effects of conventional anaerobic digestion and sludge pre-treatments on micropollutants in RDCO sludge. Data from this project is currently being analyzed and will be used to help guide future decisions. It is anticipated the overall completion of this project to be August 31, 2017.

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