Fate of selected RCRA compounds in a pilot‐scale activated sludge system

Abstract

This research determined the removal and fate of 11 selected RCRA compounds in a pilot‐scale activated sludge system with a 4‐day SRT and 7.5‐hour HRT. Screened and degritted raw wastewater from a Cincinnati, OH, wastewater treatment plant was used for this study at the U.S. EPA's Test and Evaluation (T&E) Facility. A continuous feed of spike toxic cocktail of 0.25 mg/L each of acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, carbon tetrachloride, 1,1,1‐trichloroethane, 1,1,2‐trichloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and ethylbenzene was used to produce an acclimated biomass. The test was run for 7 weeks. Volatilization losses in primary sedimentation exceeded 10% for carbon tetrachloride, 1,1,1‐trichloroethane, 1,1,2‐trichloroethane, and tetrachloroethylene. Sorption of the 11 compounds to primary and secondary sludge ranged from 0.6 to 5.1%. Nine of the 11 test compounds were removed >94% with estimated biodegradation ranging from 0 to 93.4%.

Removal kinetics of acetone and MIBK from a complex industrial wastewater by an acclimatized activated sludge

“…Acetone has a very low octanol/water partition coefficient, K ow , of 0.575 [21]. The observation that acetone is not greatly adsorbed onto suspended solids found here is in agreement with the reports in the literature [6,8,15,16]. The data obtained were used to describe the volatilization of acetone from this experiment, with a first-order rate (K v ) constant of 0.58 day −1 (r 2 = 0.66, data not shown).…”

“…Eliosov et al [7] also investigated acetone removal from two different municipal treatment works activated sludges and found substantial removal. Bhattacharya et al [8] observed that the removal of acetone in a spiked toxic cocktail with other volatile organic compounds (VOC) in a pilot scale-activated sludge system. Yet, despite the overwhelming reports of acetone biodegradation, there is contradictory evidence to these reports.…”

Temporal and Longitudinal Characteristics of Volatile Organic Compound Emissions from Aeration Units of Publicly Owned Treatment Works

“…Assumptions made for the plug flow model are (1) gas phase and liquid phase concentrations are uniform in the width direction; (2) there is no back mixing in the x direction for liquid or the z direction for gas; (3) liquid is well mixed in the z direction so that the liquid phase concentrations in the vertical plane of any position x are uniform; (4) drift of air bubbles with liquid is negligible, because the rise velocities of the bubbles are much higher than water flow; and (5) according to previous studies, [20][21][22] VOC removal by adsorption on the solids in aeration tanks is negligible; therefore, the major removal mechanisms that are considered include volatilization, biodegradation, and removal with the effluent; (6) the active biomass concentration is uniform throughout the tank; (7) the kinetics of VOC biodegradation is of the Monod type and can be further simplified to a first-order relationship to liquid phase concentration; and (8) the system is at steady state. Assumption 5 will result in an overestimation of the biodegradation rate constants.…”

Emissions of Organic Compounds in Surfactant Solutions under Air Turbulence

“…Because industrial wastewater contains various organic compounds, the issue regarding emissions of the organic compounds from wastewater treatment plants (WWTPs) has been gradually emphasized (Mayer et al, 1994;Schmid et al, 2001;Lin and Chou, 2006;Oskouie et al, 2008). Over the past decade, numerous researchers developed a series of models to predict the fates of organic compounds in WWTPs (Ince and Inel, 1991;Parker et al, 1993;Hsieh et al, 1994;Melcer, 1994;Bhattacharya et al, 1996). However, these models only provided potential emission amounts of organic compounds under specific environmental conditions.…”