The scope of this study was directed to examine different wastewater treatment technologies (activated sludge, trickling filter, nanofiltration, reverse osmosis) at full-scale facilities in Arizona and California leading to indirect potable reuse and their capability to remove pharmaceuticals. Additionally, the fate of selected pharmaceuticals was studied during soil-aquifer treatment (SAT) at sites where secondary and tertiary treated effluents are used for subsequent groundwater recharge. Facilities employing longer detention times during treatment (nitrifying and denitrifying plants) showed significant lower effluent concentration for analgesic drugs as compared to trickling filter or activated sludge facilities applying shorter detention times. A similar trend was observed for the lipid regulator gemfibrozil, which was significantly removed in denitrified effluents, whereas a trickling filter treated effluent exhibited concentration of 1,235 ng/L. Antiepileptic drugs, such as carbamazepine and primidone, showed no dependency on the wastewater treatment applied. None of the investigated drugs was detected in tertiary treated effluents after nanofiltration or reverse osmosis. After SAT, analgesic/anti-inflammatory drugs were efficiently removed after retention times of less than 6 months and remaining concentrations were near or below the detection limit of the analytical method. A high potential for biodegradation was also observed for anti-inflammatory drugs in groundwater recharge systems. The antiepileptics carbamazepine and primidone represented the most dominant of all investigated drugs in well treated domestic effluents (nitrifying/denitrifying plants). Removal of carbamazepine and primidone did not seem to occur during travel times of more than 6 years in the subsurface.

This study investigated the use of ultra-low-pressure reverse osmosis (ULPRO) and nanofiltration (NF) membranes for water reuse applications where lower operating pressures and a high permeate quality are desired. A laboratory-scale investigation was performed to compare the rejection and operational performance of RO, ULPRO, and NF membranes and to select two membranes for testing at a California water facility. A ULPRO membrane and an NF membrane were then tested at pilot and full scale at a water recycling plant and monitored for operational performance and rejection of total organic carbon, total nitrogen, and regulated and unregulated organic micropollutants. Pilot-and full-scale testing of the best-performing membranes demonstrated that both ULPRO and NF membranes could be used to meet potable water quality requirements. The presumed advantage of using ULPRO and NF membranes diminished as fouling occurred, resulting in operating pressures only slightly lower than or similar to those found for traditional RO membranes. n increasing number of municipalities are using surface water that has been affected by wastewater discharges or reclaimed water for drinking water augmentation. For groundwater injection projects in the United States that use reclaimed water, treatment using an integrated membrane system such as microfiltration (M F) pretreatment followed by reverse osmosis (RO ) is the industry standard (N RC, 2004). RO membranes are favored for these applications because of their high removal efficiencies for total dissolved solids, pathogens, and unregulated trace organic chemicals. For direct injection into a potable aquifer in California, the California Department of Public H ealth (CDPH ) draft regulations for groundwater recharge with reclaimed water require RO treatment and effluent water quality of < 0.5 mg/L total organic carbon (TO C) and < 5 mg/L total nitrogen (TN ; CDPH , 2007). Currently, there is the potential to lower operating pressures and costs by implementing newer types of membrane processes such as nanofiltration (N F) and ultra low-pressure RO (ULPRO ) for these types of applications. H owever, an understanding of the advantages and disadvantages of using ULPRO and N F compared with conventional RO membranes in terms of operational performance and permeate water quality is lacking.

A scientific advisory panel was convened by the State of California to recommend monitoring for chemicals of emerging concern (CECs) in aquatic systems that receive discharge of municipal wastewater treatment plant (WWTP) effluent and stormwater runoff. The panel developed a risk-based screening framework that considered environmental sources and fate of CECs observed in receiving waters across the State. Using existing occurrence and risk threshold data in water, sediment, and biological tissue, the panel applied the framework to identify a priority list of CECs for initial monitoring in three representative receiving water scenarios. The initial screening list of 16 CECs identified by the panel included consumer and commercial chemicals, flame retardants, pesticides, pharmaceuticals and personal care products, and natural hormones. The panel designed an iterative, phased strategy with interpretive guidelines that direct and update management actions commensurate with potential risk identified using the risk-based framework and monitoring data. Because of the ever-changing nature of chemical use, technology, and management practices, the panel offered recommendations to improve CEC monitoring, including development of bioanalytical screening methods whose responses integrate exposure to complex mixtures and that can be linked to higher-order effects; development or refinement of models that predict the input, fate, and effects of future chemicals; and filling of key data gaps on CEC occurrence and toxicity. Finally, the panel stressed the need for adaptive management, allowing for future review of, and if warranted, modifications to the strategy to incorporate the latest science available to the water resources community.

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