In most countries, the anaerobic pond has been used to achieve a high reduction in BOD , oil and grease and suspended solids concentraions from the primary treated slaughterhouse westewater prior to subsequent aerobic treatment.Unfortunately, the propensity for odour generation from anaerobic ponds has threatened their continued use in manyareas. Consequenrly, new developments in anaerobic technology during the last 15 years are of considerable interest. These can de divided into two groups:
(i) covered anaerobic ponds,
(II) high rate anaerobic sytems