Dague et al.(1990) describe the successful insta-lation and operation of a very large coered anaerobic pond for a US pork processing company. The design HRT and BODs loading were 8.8 days and 0.33 kg/m .day, respectively. In practice, average retention times were higher (12-14 days ) and BOD loadings lower (0,1 kg/m. day).but mean BODs removals of 85-90% were consistently obtained and biogas prodution averaged 0.51 m methane/kg BOD5 removed. The system paid for itself within 2 years through the use of the biogas in a netural-gas -fired boiler. Considerable, but variable, levels of H2S (mean, 843 ppm) may be generated from anaerobic ponds and this toxic and corrosive gas must beremoved, for example by iron sponge filters, beforeuse (kayhanian & Hills, 1988). Recently, a slaughterhouse ni Australia has installed two covered anaerobic ponds, which appear to operete successfully. The gas produced is flared.