Performance Evaluation at a Long-Term Food Processing Land Treatment Site

摘要

The objective of the project was to determine the performance of a fullscale, operating overland flow land (OLF) treatment system treating nonhazardous waste. The long-term operation and performance data indicated that the OLF system consistently achieved a very high level of treatment and pollutant removal, from a surface discharge standpoint. With respect to a control area, located at the OLF site but not subjected to wastewater application or impacts, the accumulation of organic carbon, potassium, zinc, and nickel in the soil at wastewater application areas was evident, as well as the apparent leach of calcium, sodium, sulfate. Neither accumulation nor leaching of chromium, magnesium, and chloride were evident. Although the accumulation of zinc and nickel was evident, the cumulative soil concentrations were well below EPA recommended limits, and several hundred years of continued site use may be expected at present loading rates. Groundwater below the OLF site was moderately saline due to the presence of sodium, calcium, magnesium, chloride, and sulfate. No purgeable or extractable organics were detected. Geochemical data indicates the enhanced dissolution and leaching of naturally present soil minerals is due to the infiltration of large volumes of treated wastewater.