INFLUENCE OF ENVIRONMENTAL CONDITIONS ON THE SEPARATION OF ORGANIC MATTER CONTAINED IN LIVESTOCK WASTEWATER BY FREEZE CONCENTRATION

, Young-Chae; , Eun-Kyung; , Sun-Kee

Environmental Engineering Research 2001;6(4): 261-267.

Young-Chae ¹^†, Eun-Kyung ², and Sun-Kee ³

¹Division of Civil and Environmental Engineering, Korea Maritime University, Pusan 606-791, Korea
²Environment and Process Technology Division, Korea Institute of Science and Technology, Seoul 130-650, Korea
³Department of Civil Engineering, Korea Advanced Institute of Science and Technology, Taejon 305-701, Korea

Corresponding Author: Young-Chae ,Tel: +82-51-410-4417, Fax: +82-51-410-4415, Email: soyc@hanara.kmaritime.ac.kr

Received: May 10, 2001; Accepted: October 10, 2001.

ABSTRACT

The performance of the freeze concentration for the organic matter in livestock wastewater was evaluated by at various environmental conditions using a batch freezing apparatus of which volume was 300 mL. The dissolved organic matter was separated effectively to around 98% at -3"C of freezing temperature and 300 rpm of rotation speed of freezing vessel. The separation efficiency was slightly improved as the wastewater became more dilute and it meant that the high quality effluent could be obtained by freeze concentration through series connection of the process. As concentration of the liquid concentrate was increased by the extending of freezing time, the growth rate of ice was decreased, but the separation of dissolved organic matter was maintained at over 98%. The separation efficiency of dissolved organic matter was decreased according to the increase of ice growth' rate by reduction of freezing temperature. Improvement of separation efficiency by only increase of agitation intensity was limited, but the growth rate of ice crystal could be enhanced. The separation efficiency for suspended solids(SS), overall, was a little lower as 92% than that of the dissolved organic matter, which was resulted from the lower selectivity of growing ice crystal for SS. The performance of freeze concentration for SS separation was more sensitive to the change of freezing conditions than that of organic matter.