Abstract

Stabilization ponds are one of the best low-cost alternatives for collection and treatment of human and industrial wastes, using only algae and bacteria to break down the organic matter. This project will study the possibility of using the algae to produce fish by selecting species of fish which are least susceptible to invasion of bacteria and virus. The researchers will study public health aspects of fish grown in sewage-fed ponds to develop operational criteria for the wastewater-treatment/fish-culture process, including appropriate loading rates, fish species composition, stabilization pond operational regimen, and depuration process requirements.

Post-Project Summary

Researchers conducted laboratory and field studies with Tilapia, Carp, and Silver carp to assess the effects of a wastewater environment. In laboratory tests, fish were inoculated with various bacteria and viruses, then dissected to examine pathogen levels in the blood, muscle, and organs. Fish immersed in water with varying concentrations of bacteria were also dissected and assessed. Patterns of bacterial penetration were similar in all fish and researchers determined the threshold levels of bacteria that would penetrate into muscle tissue. Field experiments conducted in four ponds showed a correlation between pathogens in the water and in fish organs. Tilapia was least affected by high levels of bacteria. Researchers established limits for concentrations of major pollutants as a guideline for wastewater fish ponds. Depuration was found to be ineffective when bacteria were already present in fish muscle. Researchers concluded that fish culture in wastewater ponds was feasible provided that proper dilution levels were maintained.

Recipient Institution(s)