Publications by authors named "Wendell O Khunjar"

In this study, a modeling framework was developed to simulate biologically active filtration (BAF) headloss buildup in response to organic removal and nitrification. This model considered not only the biofilm growth on the BAF media but also the particle deposition in the BAF bed. In addition, the model also took temperature effect into consideration.

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Water treatment combining advanced oxidative processes with subsequent exposure to biological activated carbon (BAC) holds promise for the attenuation of recalcitrant pollutants. Here we contrast oxidation and subsequent biofiltration of treated wastewater effluent employing either ozone or UV/HO followed by BAC during pilot-scale implementation. Both treatment trains largely met target water quality goals by facilitating the removal of a suite of trace organics and bulk water parameters.

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To predict TOrC fate in biological activated sludge systems, there is a need to accurately determine TOrC biodegradation kinetics in mixed microbial cultures. Short-term batch tests with salicylic acid, 17α-ethinylestradiol, nonylphenol, trimethoprim and carbamazepine were conducted with lab-scale activated sludge cultures in which the initial TOrC concentration (1mg/L and 0.0005mg/L) and readily biodegradable substrate concentrations were varied.

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Rationale: Monitoring the concentrations of pharmaceuticals and personal care products (PPCPs) in wastewater is an integral step toward understanding the fate of these contaminants in wastewater treatment plants (WWTPs). This paper aims to develop a method that allows for the simultaneous analysis of multiple classes of PPCPs that can be used as tracers to assess the performance of WWTPs.

Methods: Five PPCP tracers - carbamazepine (CBZ), 17α-ethinylestradiol (EE2), nonylphenol (NP), salicylic acid (SA), and trimethoprim (TMP) - were analyzed by liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) using a highly basic mobile phase (pH 10.

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The storage of renewable electrical energy within chemical bonds of biofuels and other chemicals is a route to decreasing petroleum usage. A critical challenge is the efficient transfer of electrons into a biological host that can covert this energy into high energy organic compounds. In this paper, we describe an approach whereby biomass is grown using energy obtained from a soluble mediator that is regenerated electrochemically.

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The specific solid retention time for different bacteria within flocculent and granular sludge was determined. Samples were collected from reactor and effluent sludge and the number of a specific bacterial group was evaluated in respect to the total bacterial community with quantitative polymerase chain reaction (qPCR). The ratio of the relative presence of a specific bacterial group in the reactor sludge and wasted sludge was established to observe if preferential wash-out occurred.

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The sorption of carbamazepine (CBZ), iopromide (IOP), trimethoprim (TMP) and 17α-ethinylestradiol (EE2) was evaluated using four biomass types (pure ammonia oxidizing bacterial culture, two heterotrophic enrichment cultures with varying levels of oxygenase activity, and a full-scale nitrifying activated sludge (NAS) culture). CBZ and IOP did not sorb to the four biomass types. EE2 did not sorb to the pure culture but sorbed significantly to the heterotrophic cultures and NAS.

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