Water scarcity and increasing demands on water resources have led to a rise in advanced treatment of wastewater for potable and non-potable water reuse. Despite the benefits of reducing reliance on natural water bodies, the increased implementation of reclaimed water systems has created concerns for environmental toxicity. The environmental fate and toxicity of emerging contaminants (ECs) present in treated effluent has been an area of intensive study in recent years. Compounds present in influent streams that are not completely removed, remain in discharged effluent and are introduced into the environment through the application of reclaimed water or biosolids; some of which cause negative toxicologic effects, such as endocrine disruption in fish. The diversity and numbers of different pharmaceuticals and personal care products present in domestic wastewater also may vary greatly in different cultural contexts and under aerobic and anaerobic conditions.  To better understand the presence and transformation of ECs through aerobic and anaerobic wastewater treatment in different settings, this study employed a non-targeted analysis on samples collected from two conventional wastewater treatment facilities in Durban, South Africa and California, USA using primarily aerobic systems, and from one decentralized system using anaerobic baffled reactor treatment in South Africa. Samples were analyzed with two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOF/MS). This non-targeted approach is advantageous, in comparison to targeted methods, because it can identify both known and previously unknown compounds which exist in wastewater effluent streams. To further investigate differences in EC transformation under aerobic and anaerobic conditions, samples from bench-scale parallel aerobic/anaerobic membrane bioreactor systems, fed with raw wastewater from California, USA, were analyzed for polarity and mass spectral information using GCxGC-TOF/MS, and ECs were identified using a Statistical Compare processing software. The comparison of results from the influent to effluent identified numerous compounds that persisted through treatment, and some were identified to have toxic and long-term negative health consequences for humans and aquatic life. Findings of compounds that persist through various wastewater treatment systems supplement existing knowledge and have important implications for water reuse.

Fate of emerging contaminants in aerobic and anaerobic wastewater treatment: Non-targeted approach

2019 Fall National Meeting

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