Abstract
Agricultural water quality standards were reviewed through rice culture using treated sewage irrigation . The seqage from school building of Konkuk University was treated by a constructed wetland system, and theeffluent of the systeml was irrigated for rice culutre after nutrient concentration adjusted by dilution. Average concentration of COD, SS, T-N and T-P in irrigated water was 22.3mg/$\ell$, 6.5mg/$\ell$, 25.8 mg/$\ell$and 2.2mg/$\ell$, respectively. Treatment include irrigation of adjusted effluent with conventional fertilization (TWCF), adjusted effluent with no fertilization (TWNF). and effluent of the wetland system as it was with no fertilization (SWNF). These treatment plots were compared with control plot irrigated by tap water with conventional fertilization (CONTROL). Other environmentals for rice culture were identical for all the plots. Among them, TWCF showed the best growth rate and the highest yield, and constituents in the harvested rice showed not much difference among them. Which implies that irrigation with relatively high nutrient concentration compared to the current water quality standards may cause no adverse effect on rice culture and could be even beneficial . Although T-N for this study was 25 times greater than the current standards, rice culture wasnot adversely affected by irrigatino water quality and even beeter results were observed than the CONTROL. It could be mistakenly that clean irrigation water produces better agricultural product, however, it is not necessarily true. Irrigation water with moderate nutrient concentration can enhance the plant growth, and better result might be expected. Therefore, peer review and modification if necessary are needed to the current agricultural water quality standards, especially for the nutrient components.
