poster - International Conference of Agricultural Engineering

Reclaimed wastewater reuse has been considered as an alternative water resource
due to the shortage of established water resources and increasing water demand. Reclaimed
wastewater having relatively constant volume throughout the year and abundant fertilizer
ingredients is widely used for agricultural irrigation in Korea (SNU, 2011).
Wastewater reuse for agriculture could be categorized as indirect (open) and direct
(closed) reuse according to the methods. While the direct wastewater reuse means that
farmers directly take the treated effluents from wastewater treatment plant (WTP) through
irrigation system, the indirect wastewater reuse can be defined as farmers take the treated
effluents diluted with fresh water from stream or reservoir after WTP discharges to
downstream. In case of indirect wastewater reuse, the adequate indirect reuse system is
required by the level of water quality at a reach of the river (Lee et al., 2010).
MOE (2011) reported a total volume of 106 million m 3 water will be annually used for
agriculture from 56 WTPs by 2020. But most of reclaimed wastewater for agriculture has
been used by means of the indirect reuse. It has been investigated that more than 130 WTPs
affect irrigation water to farmland including paddy fields in Korea (Kim et al., 2009). In case of
indirect reuse, irrigated water has not been properly treated for agricultural use and it might
cause health implications for farmers, consumers and communities. Furthermore, the soil,
plant, groundwater and other aspects of the local environment should be monitored to protect
from contaminations by reclaimed wastewater irrigation in particular if compounds
accumulate in certain phases (Huertas et al., 2008). Therefore, a study on indirect reuse of
reclaimed wastewater for agriculture should be conducted. The objective of this study is to
introduce the project of the development and application of wastewater reclamation systems
for indirect agricultural reuse in Korea.
2. Indirect wastewater reuse project for agriculture
2.1. Objectives of the project
The objectives of this project are 1) to propose proper water quality guideline for
indirect reuse of reclaimed wastewater for agricultural irrigation based on monitoring or
modeling in paddy fields, 2) to develop cost-effective wastewater reclamation systems for
indirect agricultural reuse satisfying the proposed guidelines, 3) to monitor and assess of
effects of indirect wastewater reuse on paddy rice culture for three years, and 4) to
implement the developed systems to actual agricultural districts in Korea.
2.2. Research scopes of the project
2.2.1. Effect on rice growth and yield of indirect wastewater reuse
Two monitoring sites, the Byeongjeom (BJ) and Osan (OS), were selected for indirect
reuse of reclaimed wastewater. They are located near the Suwon and Osan WTPs,
respectively, in Gyeonggi-do, Korea. Irrigated water of rice paddy fields in the BJ and OS
monitoring sites is pumped from Whangguji and Osan stream, respectively, which are
influenced by WTP effluent. The Yongin (YI) monitoring site near the Idong reservoir, which
satisfies the agricultural water quality criteria in Korea, was selected as control of
conventional water irrigation (Fig. 1.).