Abstract

A new integrated multi-environment wastewater treatment technology was evaluated for simultaneous removal of organic carbonaceous compounds as well as inorganic contaminants, notably nitrogen and phosphorus from synthetic and hog wastewater. The influent concentrations of carbon, nitrogen and phosphorus during the reported experiments on synthetic wastewater were in the range of 500 to 4000 mg/L, 42 to 200 mg/L, and 16 to 40 mg/L, respectively. The treatment system operated with food-to microorganisms (F/M) ratio of 0.95 to 3.4 (d-1) and SRT of 10 -200 days, producing removal efficiencies of 83.3% -99% for COD ,65.9%-85% for total nitrogen and 10%-100% for total phosphorus. The very high removal efficiencies obtained in this study show the proper performance of the integrated treatment system. The influent concentrations of hog waste were in the range of 1000 to 2400 mg/L, 200-230 mg/L, and 40-48 mg/L for COD, total nitrogen and total phosphorus, respectively. The system operated with organic loading rates of 0.51 to 1.43 kg COD/m3.d, nitrogen loading rates of 0.07 to 0.16 kg TN/m3.d, and phosphorus loading rates of 0.015 to 0.035 kg TP/m3.d. The solid retention time and hydraulic retention time were in the range of 12 to 33 days and 1.43 to 1.74 days, respectively. The overall COD/N/P and BOD/N/P ratio were maintained at the range of 27:4.5:1 to 70:3.64:1 and 26:4.5:1 to 69:3.64:1, respectively, for the maximum removal of contaminants along with food-to-microorganism ratio (F/M) of 1.04 to 2.57 d-1 in the mixed liquor. The removal efficiencies of COD, BOD, N and P for hog waste were in the range of as 60%-89%, 40%-89%, 10%-69% and 14%-40%, respectively. The increasing trend of contaminant removal efficiency with time during the treatment of hog waste suggests that higher removal efficiencies would be obtained if the treatment system had operated for a longer period.