Pilot-scale evaluation of design criteria for anaerobic photosynthetic lagoons treating fellmongery (unhairing) wastewater

Fellmongery wastewaters, from the unhairing of sheep pelts, were treated in a pilot-scale (4.7 m³) anaerobic photosynthetic lagoon in which the dominant microorganisms were the purple sulphur bacteria of the family, Chromatiaceae.Removals of 86% COD and 85% sulphide were obtained at a retention time of 90 days. Values of the organic and sulphide removal rate coefficients and the residual COD and sulphide concentrations are presented. The effluent quality compared favourably with predictions based upon models developed in earlier work with laboratory-scale (0.09 m³) lagoons that treated a synthetic fellmongery wastewater under controlled conditions.It was concluded that lagoons in which the Chromatiaceae are the dominant population can provide a high degree of treatment for fellmongery wastewater and that laboratory-scale models can adequately predict effluent quality from such lagoons.