ABSTRACT

One major concern in using wastewater for agricultural irrigation is the potential public health hazard resulting from exposure to pathogenic organisms. Pathogens that can survive modern wastewater treatments include bacteria, protozoa, helminths, and viruses. There is very little evidence indicating a potential health hazard in handling disinfected wastewater for irrigation on agricultural land. Survival of enteric bacteria in soil is dependent on several factors, including soil moisture content, temperature, pH, season of the year, sunlight, organic matter content, and antagonistic organisms. Extreme acidic and alkaline conditions tend to adversely affect most bacteria in soil. Generally, neutrality favors the growth and survival of enteric bacteria. The migration of wastewater pathogens in soil involves transport by insects, birds, rodents, overland runoff, windblown soil, and percolation through the soil profile to ground water. Virus removal from percolating wastewater is almost totally dependent on adsorption to various soil components.