A screening protocol has been developed to provide a rapid but dependable and repeatable assessment of the effect of toxic organic chemicals on anaerobic treatment processes. The protocol provides information on the rate limiting biological reactions and the concentration of toxic chemicals at which changes in reaction rate take place. General features of the protocol include (1) relative ease of use, (2) relatively short response time--days versus months, (3) low labor requirements, (4) use of conventional techniques, (5) reproducibility among laboratories, and (6) it builds on previously developed protocols and procedures. The screening protocol consists of three steps: STEP I is a prescreen to identify the range of toxic impact of a chemical; STEP II is a short-term batch test to identify the effect of slug doses of chemical and to show which anaerobic reaction is inhibited first; STEP III is a semi-continuous culture test to determine the effect of a gradual buildup of toxicant and to identify concentrations at which specific inhibitory effects take place. The results indicate the potential for using anaerobic processes for treating toxic and hazardous organic chemicals and provide a basis for anticipating toxic impacts of toxic organic chemicals on anaerobic processes.

"Published in the 1989 TAPPI Environmental Conference, 4/17-19/89, Orlando, FL." "PB92-217058." "EPA/600/A-92/169." Microfiche.