The market of the municipal wasetewater treatment plant (MWTP) operation is expanding across the world
including Korea. The contracting-out system was introduced for the effective operation of MWTPs. However,
an improvement of the contracting-out system of MWTP has been continuously required. This research
investigated current operational status of MWTPs in Korea, to suggest the improvement of the cost effective
MWTP operation to promote the contracting-out system of MWTP operation. Results showed that lower
operational costs of MWTP were lower in larger MWTPs than in smaller MWTPs. Overall, MWTPs operated
by a public enterprise showed lower operational costs than those operated by government agencies and private
enterprises. Among the MWTPs similar in their treatment capacity, treatment process and operation period,
MWTPs operated by private enterprises showed the lowest operational cost. According to the survey, managers
and operators of MWTPs emphasized the importance of improvement on the methods of selecting operating
agencies and estimating operationing costs. The results of this study should be useful as important supporting
data to promote the contracting-out system for the MWTP operation.