Septage treatment using a combined waste stabilization ponds—vertical flow constructed wetland system

Abstract Eight vertical flow small-scale constructed wetlands were introduced in a pre-existing wastewater treatment pilot plant consisting of three interconnected waste stabilization ponds—a facultative pond followed by two maturation/aerobic ones. The wetlands were identical in couples but differed in substrate and plant presence (common reed) and were fed from the outflow of the first maturation pond. The system was monitored for two years in order to study its operation and efficiency for the treatment of septage in an open air experiment. Samples were collected twice a month and TSS, BOD5, pH, EC, TP, N- and N- were monitored. BOD5 removal was greater in the summer months. The unplanted wetlands were more efficient in TSS and BOD5 concentrations removal. Still, when estimating the BOD5 mass in the constructed wetlands effluents using Thornthwaite model to adjust the results, it was found that the BOD5 mass of unplanted wetlands effluents is greater than that found in planted ones. The system did not ...