TREATMENT OF HIGH-CONCENTRATION SWINE WASTEWATER BY ANAEROBIC DIGESTION AND AN AQUATIC PLANT SYSTEM

Kim, B. V.; Kwon, J. H.

doi:2006.11.3.134

Environmental Engineering Research 2006;11(3): 134-142. DOI: https://doi.org/10.4491/eer.2006.11.3.134

TREATMENT OF HIGH-CONCENTRATION SWINE WASTEWATER BY ANAEROBIC DIGESTION AND AN AQUATIC PLANT SYSTEM

¹Gangwon Institute of Health & Environment, 728, Sancheon2-ri, Shinbuk-eup, Chuncheon, Gangwon, 200-822, Korea
²Department of Environmental Prevention Engineering, Kangwon National University, Samcheok, Gangwon, 245-711, Korea

Corresponding Author: B. V. Kim ,Tel: +82-33-250-1767, Fax: +82-33-250-1749, Email: bukiml@hanmail.net

Received: January 8, 2006; Accepted: February 10, 2006.

ABSTRACT

The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system was investigated. Anaerobic digestion of swine wastewater gave volatile solids (VS) removal efficiencies of 43.3%, 52.1% and 54.5% for hydraulic retention times (HRTs) of 20, 30, 40 days, respectively. The removal efficiencies of VS, total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) decreased with increasing VS volumetric loading rate (VLR). Higher organic removal efficiency was observed at longer HRTs for the same VS volumetric loading rate. As VS volumetric loading rate increased, biogas production increased and the methane content of the biogas decreased. Experiments using duckweed (Lemna species) as an aquatic macrophyte gave the following results. In the case of nitrogen, removal efficiency was above 60% and effluent concentration was below 10.0 mg/L when the influent ammonia-N loading was about 1.0 g/m2/day. In the case of phosphorus, removal efficiency was above 55% and effluent concentration was below 2.0 mg/L when the influent PO4-P loading was about 0.15 g/m2/day. In addition, crude protein and phosphorus content of duckweed biomass increased from 15.6% to 41.6% and from 0,8% to 1.6%, respectively, as the influent nutrient concentration increased. The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system offers good performance in terms of organics and nutrient removal for relatively low operation and maintenance costs. The results Indicate that under appropriate operational conditions, the effluent quality is within the limits set by Korean discharge criteria.