Air stripping of acrylonitrile from waste-treatment systems

Abstract

The treatment of waste water by biological oxidation is an old and established process. In recent years, the possible risks of airborne contamination from aerated wastetreatment systems have been recognized. To provide effective protection of operating personnel and members of the general public, methods which can quantitative1 pre-Extensive test work by Gaudy [I, 2, 3, 41 in the early 1960's on laboratory and full-scale activated-sludge systems provided data on the stripping characteristics of acetone, butyraldehyde, valeraldehyde, pro ionaldehyde, model which could account for the simultaneous biological oxidation and air volatilization which occur in activated-sludge treatment plants. Other experimental work by Dilling [5], Richardson [6], and Smith [q resulted in the accumulation of much data on the volatilization rates of various organic compounds. Recently, Stover [8] has presented data and correlations on the rate of volatilization of various organic chemicals from laboratory-scale activated-sludge systems.Thibodeaux [9, 10, 11, 121 developed a generalized model to redict the air volatilization rate of organics from Thibodeaux's work to include simultaneous biological oxidation and volatilization of the organic contaminate. Recently, Hwang [16] has applied these models to the problem of toxic emissions from land-disposal facilities. This paper presents the results of a laboratory study conducted to develop data for verification of the Freeman-model predictions. Acrylonitrile was chosen as the hazardous chemical to be studied. Described in this paper are the experimental methods used to start up and operate bench-scale wastewater-treatment systems, including a description of the experimental apparatus and the daily operating procedures; the sampling and analysis rocedures used to colacrylonitrile concentration; significant results; and conclusions. dict the emission rates of volatile organics are nee K ed. and butanone. Gaudy's work did not resu P t in a general an aerate B treatment basin. Freeman [13,14,15] extended lect air, water, and sludge samp P es and determine the EXPERIMENTAL METHODSThree continuous-flow, bench-scale biologicaloxidation systems were designed, constructed, and operated in laborator hoods for a minimum of 45 days to deteracrylonitrile. The systems were designed to operate at

Environmental Assessment During Intelligence Preparation of the Battlefield (IPB) - Evaluation of the TIC-Master Computer Program

“…The hydrolysis of acrylonitrile is slow, with half-lives under acidic and basic conditions of 13 and 188 years, respectively (Ellington et al, 1987 AN Group, 1996;BASF AG, 1996). However, acrylonitrile will be extensively degraded (95-100%) following a short acclimation period if emitted to wastewater treatment plants (Tabak et al, 1980;Freeman & Schroy, 1984;Watson, 1993).…”

Monitoring and modeling VOCs in wastewater facilities

“…They have been used to predict emissions for air permitting purposes (72). Many models have been developed, but not all are computer-based (39,46,50,(73)(74)(75)(76)(77)(78)(79). They include equations that describe the VOC removal mechanisms described above with differing degrees of refinement relating to mass transfer assumptions and methods of calculating rate coefficients.…”

Monitoring and Modeling VOCs in Wastewater Facilities

“…They have been used to predict emissions for air permitting purposes (72). Many models have been developed, but not all are computer-based (59,46,50,(73)(74)(75)(76)(77)(78)(79). They include equations that describe the VOC removal mechanisms described above with differing degrees of refinement relating to mass transfer assumptions and methods of calculating rate coefficients.…”

“…Ittakes account of all VOC removal mechanisms. PAVE simulates only complete-mix activated sludge systems and incorporates complex biological kinetic models(79). It can Environ.…”