In this study, a pilot-scale (3 m3/day) membrane distillation (MD) process was operated to treat digestate produced from anaerobic digestion of livestock wastewater. In order to evaluate the performance and energy cost of MD process, it was compared with the pilot scale (10 m3/day) reverse osmosis (RO) process, expected competitive process, under same feed condition. As results, MD process shows stable permeate flux (average 10.1 L/m2/hr) until 150 hours, whereas permeate flux of RO process was decreased from 5.3 to 1.5 L/m2/hr within 24 hours. In the case of removal of COD, TN, and TP, MD process shows a high removal rate (98.7, 93.7, and 99% respectively) stably until 150 hours. However, in the case of RO process, removal rate was decreased from 91.6 to 69.5% in COD and from 93.7 to 76.0% in TP during 100 hours of operation. Removal rate of TN in RO process was fluctuated in the range of 34.5-62.9% (average 44.6%) during the operation. As a result of energy cost analysis, MD process using waste heat for heating the feed shows 18% lower cost compare with RO process. Thus, overall efficiency of the MD process is higher then that of the RO process in terms of permeate flux, removal rate of salts, and operating cost (in the case of using waste heat) in treating the anaerobic digestate of livestock wastewater.

ABSTRACT
1. 서 론
2. 재료 및 실험방법
    2.1 실험장치 개요
    2.2 실험 조건
    2.3 시료 분석
    2.4 경제성 분석
3. 결 과
    3.1 투과유속
    3.2 COD, TN, TP 제거율
    3.3 경제성 분석
4. 결 론
References

• 김승환(서울대학교 건설환경공학부) | Seunghwan Kim (Department of Civil & Environmental Engineering, Seoul National University)
• 조진우(세종대학교 환경에너지공간융합학과) | Jinwoo Cho (2Department of Environment, Energy & Geoinformatics, Sejong University) Corresponding author