ANAEROBIC TOXICITY AND BIODEGRADATION OF FORMALDEHYDE IN BATCH CULTURES

The anaerobic degradation of formaldehyde with glucose and wood-glue wastewater was studied in batch cultures. Under test conditions the toxicity of formaldehyde to anaerobic degradation was dependent on the concentration of formaldehyde, the compounds of the wastewater and test time. The 50% inhibition concentration was about 300 mg litre−1 for tests with glucose and about 150 mg litre−1 for tests with wood-glue wastewater. The inhibition under the critical concentration changed with the test time. The removal of formaldehyde was inhibited only with relatively high formaldehyde concentrations in comparison to gasification and COD. Under 200 mg litre−1 (tests with glue wastewater) or 400 mg litre−1 (tests with glucose), more than 90% formaldehyde was degraded. The strong inhibition of formaldehyde removal took place after the corresponding formaldehyde biomass load was more than 63 mg-F g−1 OTS (tests with glue wastewater) or 126 mg-F g−1 OTS (tests with glucose). Moreover, it was observed that the VFA were very low, when the formaldehyde concentration was over 200 mg litre−1. © 1998 Elsevier Science Ltd. All rights reserved