Recovery and utilization of useful by-products from egg processing wastewater by electrocoagulation.

The efficacy of a laboratory electrocoagulation (EC) system for treating egg processing plant waste-water (WW) is reported. For simulated and industrial egg processing WW, chemical oxygen demand, turbidity, and total suspended solids (TSS) were reduced 92 to 97%, 97%, and 99%, respectively, after treatment with EC. The final TSS concentration and turbidity values were 30 mg/L and 5 formazin turbidity units (FTU), respectively, similar to that of potable water standards. The recovered by-product solids had a similar pattern of essential amino acids compared to that of liquid whole egg and were comparable to the Food Agriculture Organization's essential amino acid profile for an ideal protein. The relative protein digestibilities of the recovered solids and a commercial corn meal averaged 130 and 56%, respectively, compared to liquid whole egg (set at 100%). An economic analysis of EC indicated that this treatment is economically feasible in that a savings of approximately $425,000 per year is possible in addition to recovering the capital equipment costs after about 14 mo of operation. These findings demonstrate that EC can be successfully applied to treat egg processing plant WW, yielding a high quality water suitable for recycling and valuable by-products having a highly digestible protein and fat value.