Analysis of Water Quality and Soil Environment in Paddy Fields Partially Irrigated with Untreated Wastewater

Abstract

The objectives of this study were to monitor and analyse water quality and soil property in paddy fields where untreated wastewater is irrigated. Three paddy fields where streamflow mixed with untreated wastewater has been irrigated (untreated wastewater district, UWD) were selected for monitoring, and five paddy fields in Yongin area (Yongin district, YID) where water from Idong agricultural reservoir (well-managed) has been irrigated were selected for comparative evaluation. Electronic conductivity (EC), suspended solids (SS), total nitrogen (T-N), total phosphorous (T-P), NO3-N, Ca 2+ , Mg 2+ , Na + , total coliform (TC), fecal coliform (FC), and E. coli of the irrigation water in the UWD were significantly higher than those in the YID. Relatively high concentrations of EC, T-N, T-P, TC, FC, E. coli, copper (Cu), lead (Pb), zinc (Zn), and aluminium (Al) were shown in the irrigation water of the UWD especially during May to June. In general, the paddy soil in the UWD contained more Pb, Zn, and Cu than in the YID although the soil heavy metal contents in the UWD still meet the Korean soil contamination warning standards. No temporal trends in the heavy metal concentrations were found in paddy soils of the UWD. This study showed that the use of untreated wastewater to paddy fields has the possibility of negative impacts on water quality and soil, although long-term monitoring is needed to fully evaluate its effects.

Irrigation Water Quality Standards for Indirect Wastewater Reuse in Agriculture: A Contribution toward Sustainable Wastewater Reuse in South Korea

“…Even for sites irrigated by relatively clean water derived from a reservoir, an average of about 15,700 MPN/100 mL of total coliform was detected [20]. It was also found that the total coliform of the irrigation water containing untreated wastewater was about 77,000 MPN/100 mL [21]. QMRA on paddy irrigation showed that the human health risk of irrigating treated wastewater is nine times higher than that of irrigating groundwater [42], but even with the extremely high level of total coliform, there have rarely been any reports of human harm from using treated or untreated wastewater for rice paddy irrigation.…”

“…This indicates that the subjected level of total coliform can be easily found in nature and is inadequate as an indicator for microbes. The E. coli concentration of irrigation water with high levels of total coliform concentration was measured to be 13, 46, and 107 MPN/100 mL for reservoir water, indirect wastewater reuse water, and irrigation water containing untreated wastewater, respectively [20,21]. For fecal coliform, the concentrations for the subjects above were 5000, 180, and 633 MPN/100 mL, respectively [20,21].…”

“…The E. coli concentration of irrigation water with high levels of total coliform concentration was measured to be 13, 46, and 107 MPN/100 mL for reservoir water, indirect wastewater reuse water, and irrigation water containing untreated wastewater, respectively [20,21]. For fecal coliform, the concentrations for the subjects above were 5000, 180, and 633 MPN/100 mL, respectively [20,21]. Considering the high measurement of fecal coliform, even for conventional irrigation water derived from a reservoir, there needs to be a practical regulation using E. coli, which can well reflect the pathogenic microorganism such as the regulations of Spain, Greece, and Italy.…”

“…Therefore, without additional treatment, it is suggested that diluted treated wastewater be used restrictively [19]. In addition, when using treated wastewater for rice paddy irrigation, the water showed a significant level of salinity compared to conventional irrigation water, and total coliform concentration surpassed the levels of the water quality standards for direct wastewater reuse [20,21]. Previous studies suggest that the quality of irrigation water from streams fails to meet the agricultural water quality standards due to the effects of WWTP effluent [14,22]; thus, the water quality needs to be managed to ensure safe and sound crop production.…”

Simulation of Agricultural Water Supply Considering Yearly Variation of Irrigation Efficiency

“…(Fig. 1(a)) Song et al, 2014). 이동저수지는 4∼9월에 취수탑을 통해 1,789.7ha 의 면적에 대해 농업용수를 공급하고 있으며, 홍수기에는 농업용수 공급의 지장이 없는 범위 내에서 radial gate를 .…”