Use of waste water for aquaculture: an experimental field study at a sewage-treatment plant, Egypt

Abstract

The primary and secondary treated waste effluents were successfully used to grow the Nile tilapia Oreochromis niloticus (L.). The growth rate of fish reared in treated waste water was significantly higher than that of fish reared in the natural habitat. Bacterial loads in fish organs were higher in the gills followed by the intestine and the skin and finally the edible muscles. The total aerobic bacterial count was very low (9.3 × 102 g−1) in the edible muscles of fish grown in secondary‐treated effluent and complied with the WHO guidelines (less than 105 g−1). Salmonella, Shigella and Staphylococcus were completely absent in all fish samples examined. The highest concentrations of heavy metals were found in liver tissues, followed by intestine and gills and then the muscles. Accumulation levels were within the acceptable limits when compared to the international legal standards for hazardous elements in fish and fishery products. In conclusion, chemical and bacterial analyses indicated that there is no evidence of any public health hazard associated with treated waste water reuse in aquaculture. However, the risks, if any, to the fish growers, processors and consumers should be evaluated, specially that related to viral pathogens.

An analysis of the impact of human activities on water quality and ecological responses in the Suez Irrigation Canal

“…It is clear from the presented results that the highest concentrations were found in liver tissues compared with muscle. The recorded result coincide with the finding of Khalil and Hussein (1996) who postulated that heavy metals were significantly higher in fish viscera, including liver, than in the edible muscle tissues. According to Sorensen (1991), bioaccumulation of heavy metals does not only depend on the structure of the organ but also on the interaction between metals and the target organs.…”

“…1). The higher values of (k) for the studied fish species could be attributed to the The impact of human activities high phosphorus and nitrogen that increased the water productivity and consequently increased fish growth as previously reported by Khalil and Hussein (1996).…”

Physiological Responses Influenced by Certain Heavy Metals at the Mullet Fish, Mugil cephalus Inhabiting Mediterranean Sea Coast at Damietta Governorate, Egypt.

“…This may be attributed to the changes in water quality by the action of heavy metals, that may critically influence the growth rate and quality of fish (Hodson et al, 1984). Moreover, the drainage water is generally rich with nitrogen, phosphorous and organic matter that causes appropriate changes in the physical and chemical features of water (Khalil and Hussein, 1996). From another side of view, the depletion in total lipids in the different organs during summer than the winter may be due to the use of energy-rich lipids for energy production during toxic stress.…”

Prevalence of Bacterial Pathogens and their Anti‐microbial Resistance in Tilapia and their Pond Water in Trinidad

“…The possible effect of the toxic levels of these compounds on the health, growth rate, appearance, and reproductive rates of the tilapia reared in these ponds, is unknown. In many countries (Khalil and Hussein, 1997; Escher et al., 1999), the use of raw domestic sewage or effluent from treatment plants in fish farming has been advocated with the main objective being to promote primary and secondary productivity following fertilization of the ponds. The number of bacteria in the pond water has been documented to determine the presence and concentration of bacteria in fish.…”