Algae production and harvesting from animal wastewaters

Abstract

High-rate ponds have been studied for many years as a means of treating wastewater to grow algal biomass which can then be harvested to produce a high protein feedstuff. Photosynthetic oxygenation by algae using solar energy is increasingly attractive as an energy-conserving alternative to conventional treatment processes such as activated sludge or aerated lagoons. Previous pond-harvesting investigations have, in most cases, employed sewage as the substrate but the use of wastewater from intensive animal production units provides greater opportunity for incorporation into an integrated system for utilising the harvested product. Earlier investigations are briefly reviewed and a pond-harvesting system for animal wastewater is described. Process variables in high-rate pond operation, experimental work in Australia with a 0·28 ha high-rate pond and a paper-precoated belt filter method of harvesting are also discussed.