Land Application of Wastewater:The Fate of Viruses,Bacteria and Heavy Metals at a Rapid Infiltration Site.

摘要

One mode of land application of wastewater, rapid infiltration (RI), was studied to determine if significant quantities of specific microbiological and chemical wastewater constituents could percolate into the ground water. The RI site selected for study had been in operation for over 30 years. Primary sewage effluent was used for rapid infiltration/percolation. Results indicated that neither renovated (replacement of top 3-4 feet of soil) nor unrenovated RI cell soils were capable of adsorbing viruses from primary effluent. Tracer bacteriophage penetrated into the ground water along with the percolating wastewater. The tracer and indigenous enteroviruses were sporadically detected in the ground water at horizontal distances up to 600 feet from the application point. Enteric indicator bacteria were readily concentrated on the soil surface, principally by filtration. A comparison of heavy metals and total organic carbon in the upper soil layers of renovated and unrenovated cells revealed their accumulation at the soil surface. The high metal and organic carbon concentrations disappeared from this layer after prolonged cessation of wastewater application.