Safley and Westerman (1988) and Safley and
Westerman (1992) reviewed design data for normaland
low-temperature anaerobic digestion of animal
manures. A study of the use of covered anaerobiclagoons for treating animal manure in the US has
suggested that these lagoons require high BOD
loadings to generate economic quantities of biogas.
Safley and Westerman (1988) reported that biogas
production on lightly loaded (< 0"06 kgVS/m 3) anaerobic
ponds generated only low quantities of biogas
(up to 0.5 m3/m2.day or 0.23 m3/m3.day). Gas production
is highly sensitive to pond temperature
(Safley & Westerman, 1992), although methanogenesis
occurs at temperatures as low as 4°C (Stevens
& Schulte, 1979). The higher temperature of slaughterhouse
wastewater should eliminate this problem.