The selection of technologies for the removal of trace organic compounds (TOrC) from wastewater will continue to emerge as an important factor that influences capital upgrades at water resource reclamation facilities of the future (WRRFs). The use of existing biological treatment infrastructure to achieve enhanced TOrC biodegradation can potentially allow utilities to meet strict nutrient limits while also remediating TOrC. In this work, a short-term batch testing protocol was developed and deployed for assessing TOrC biotransformation and sorption rates of removal. Results from lab-scale experiments indicated that of the five TOrC, salicylic acid (SA), 17a-ethinylestradiol (EE2) and nonylphenol (NP) could be classified as readily biotransformable, trimethoprim (TMP) was moderately biotransformable while carbamazepine(CBZ) was slowly transformable.<br/>Results from testing at full-scale facilities suggest that strategies that aim to enhance attenuation of SA, EE2 and NP should focus on maximizing the aerobic reaction time under carbon limited conditions (HRT<sub>AER,Climit</sub>). In contrast to SA, EE2 and NP results, TMP biotransformation rates were variable and showed no preference for anaerobic, anoxic or aerobic conditions. Taken together, these results demonstrate that increasing the carbon limited HRT would potentially increase the extent of SA, EE2 and NP removal. As a result it should be expected that biotransformation of SA, EE2 and NP would be lower in high rate activated sludge systems in which low solids retention times (SRTs) and hydraulic retention times limit biotransformation. In contrast, enhanced degradation of SA, EE2 and NP may be achieved by employing biological nutrient removal technologies that require operation at SRTs in excess of 7 days and HRTs in excess of 6 to 8 hours.

Assessment of the biodegradability of trace organic contaminants during biological treatment in water resource recovery facilities

2019 Fall National Meeting

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