About 400 m3/d of raw sewage from the City of Suez were diverted and treated by two parallel pond systems. The first treatment system was conventional Waste Stabilization Ponds which included anaerobic, facultative, and maturation compartments for a total residence time of 21 days. The second system included a series of four plankton ponds with a total residence time in the order of 26 days. The effluent from these inexpensive, but yet effective treatment technologies, was found to conform to the World Health Organization (WHO) standards for unrestricted agricultural and aquacultural applications. The treated waste effluent was successfully used to grow two types of local fish, i.e.Oreochromis niloticus and Mugil sehli. Fish production, without supplemental feeding or pond aeration, reached 5-7 metric tons/hectare/year. Furthermore, the fish were found to be free from human parasites and safe for human consumption. The nutrient rich effluent from the fish pond was further used to grow trees and cultivate certain types of crops, i.e. barley, maize, beets and ornamental plants. This study clearly demonstrates the effectiveness and benefits of waste stabilization ponds systems for low cost treatment of domestic waste and the combined reuse in aquaculture and agriculture applications. In addition, the unique treatment/reuse facilities constructed at Suez will continue to function as an experimental station and serve scientists and engineers to study and to plan applications in Egypt and the region.

Public health and safety concerns have traditionally been the main reasons for resisting waste water reuse for fish farming. Potential adverse health effects in such applications could be avoided if the waste is sufficiently treated before reuse. In a full scale demonstration study in Suez, Egypt, about 400 m3/d of raw sewage were treated using a multi-compartment stabilization pond system, for a total residence time from 21-26 days. The treated effluent conformed to WHO guidelines and was used for rearing two types of local fish (tilapia and gray mullet). The produced fish were subjected to an extensive monitoring program. Bacteriological examination revealed that in all samples the fish muscles were free of bacterial contaminants. Nevertheless, low levels of Escherichia coli andAeromonas hydrophila, were isolated from the surface of the fish. Salmonellae, shigellae and staphylococcus aureus were absent from the surface of all the fish sampled. In addition, toxic metals (Pb, Cu, Zn, and Cd) were found to be at much lower levels than the international advisory limits for human consumption. It is concluded that fish reared in the treated effluent at Suez Experimental Station is (a) suitable for marketing for human consumption, and (b) it's quality is equal or better than fresh water fish in Egypt.

No abstract

No abstract

No abstract