Public health implications of waste water reuse for fish production

Abstract

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.

Worldwide Regulations and Guidelines for Agricultural Water Reuse: A Critical Review

“…Despite the potential negative consequences of these chemical constituents, only 17 regulations and/or guidelines included some of these chemical parameters ( Table 7). Among the studied regulations and guidelines, Italy, China, Oman, and AGWR have included the highest number of chemical constituents in their documents (32,22,21, and 20 chemical parameters respectively, Table 7). Table 7.…”

“…However, those parameters were not used by all of the regulations and guidelines investigated in this study. For instance, pH (34), free Chlorine (25), and nutrients (21) were the most frequent parameters respectively (Figure 7). TSS (43), BOD 5 (42), and turbidity (27) were the most frequent among physico-chemical parameters used in the studied regulations and guidelines (Figure 8).…”