Separation of pollutants from restaurant effluents as animal feed, fertilizer and renewable energy to produce high water quality in a compact area

This paper demonstrates that oil and grease (O & G), chemical oxygen demandSettled (CODS) and chemical oxygen demandTotal-Settled (CODT-S) levels in restaurant wastewater can be reduced to less than 50, 400 and 160 mg/L, respectively, even during busy hours (1200–1400 h), provided it is subject to chemical treatment with dissolved air flotation (DAF). After treatment the wastewater turned very clear and may be reused for various applications. The sludge generated from flotation can be recycled as an animal feed to give a mean protein content of 8.26%, a mean phosphorus level of 0.11%, and a mean calorific value of 6690 cal/g. This can be utilized as a fertilizer and a biofuel with nitrogen and phosphorus level equivalent to those of pig manure and a calorific value higher than that of wood and coal, respectively.

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