Abstract |
The Campbell Soup Company plant at Paris, Texas, treats wastewater from the processing operations by spraying onto grassland. Vegetable solids and grease residues are separated and recovered. A comprehensive 12-month study was conducted to determine treatment efficiencies of the spray-runoff treatment system. A total of 133 inches of wastewater was applied to four experimental areas during the study period. Hydrological measurements, chemical removal efficiencies, and changes in soil properties were evaluated in relation to years of wastewater application, soil type, and spray schedule. Hydrological measurements accounted for 93 percent of the total liquid applied and showed that evaporative losses accounted for 18 percent of the total liquid applied; runoff accounted for 61 percent. During periods of heavy rainfall, runoff increased to a maximum of 80 percent of the total applied liquid. The results showed that the system achieved mass removals of 92 to 99 percent of the volatile solids and oxygen-demanding substances, 86 to 93 percent of total nitrogen, and 50 to 65 percent of phosphorus. Soil textural class and system age had very little effect on treatment efficiencies. Evaluation of surface and subsoil samples and soil water at the 3-foot depth indicated an increase in salinity with age, but nitrogen and phosphorus remained low. Much of the phosphorus removed from the wastewater was found in the surface soil layer. (Author) |