• 한국농공학회논문집
• /
• 제56권6호
• /
• pp.19-29
• /
• 2014

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), $NO_3-N$, $Ca^{2+}$, $Mg^{2+}$, $Na^+$, 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.

• 한국농공학회논문집
• /
• 제53권4호
• /
• pp.67-74
• /
• 2011

The objectives of this study were to assess the rice yields and evaluate fertilizer reduction effect of reclaimed wastewater irrigation in paddy fields using the Decision Support System for Agrotechnology Transfer (DSSAT) v4.5 model. The experimental plots were designed, which was located near the Suwon wastewater treatment plant in Gyeonggi-do, Korea. The rice yield, irrigation amount, irrigation water quality and soil data were monitored and collected between 2006 and 2009. The DSSAT model was calibrated and validated with observed data. The methods that were used to evaluate this model were the root mean square error (RMSE), normalized root mean square error (nRMSE), and index of agreement (d). The values of RMSE, nRMSE, and d ranged from 145 to $789\;kg\;ha^{-1}$, 3.0 to 13.3 %, and 0.90 to 0.95 for the calibration period, respectively and represented from 91 to $538\;kg\;ha^{-1}$, 2.0 to 10.4 %, 0.94 to 0.98 for the validation period, respectively. Overall, this model showed good agreement with observed data of rice yields irrigated with reclaimed wastewater. The fertilizer reduction effect in paddy field of reclaimed wastewater irrigation was assessed about 60 % in 2008 and 40 % in 2009.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2004년도 학술발표논문집
• /
• pp.4-4
• /
• 2004

• 유통과학연구
• /
• 제16권2호
• /
• pp.53-65
• /
• 2018

Purpose - The purpose of this study is to investigate the effect of gamma - irradiation on the effluent from food distribution in the large agricultural and marine products market. This study will contribute to the distribution process as well as the agricultural and fishery distribution facilities. Research design, data, and methodology - In order to reduce the odor, the smell was examined in the anaerobic digestion process by irradiating gamma rays to the wastewater of mixed food discharged from a large restaurant. An odor determination panel list was constructed to determine if the odor was present in the air dilution drainage and the odor concentration was analyzed by instrumental analysis. Results - It was confirmed that the sulfur content increased gradually from 3 months. Ammonia decreased from 33.57ppm at the initial measurement to 4.12 ppm at the end of the experiment. Methane production was highest at 100kGy when exposed to gamma rays of 0-200kGy at pH 12. In other words, it is considered that gamma irradiation doses are most effective at 100kGy and are suitable for large capacity wastewater treatment facilities in terms of economic feasibility. Conclusions - In pre-treatment of compound food wastewater, gamma irradiation is most cost effective when examined at 100kGy. The economic efficiency of the pre-treatment method by gamma irradiation is much higher than the wastewater treatment in the large-scale agricultural and marine products distribution market.

• 한국토양비료학회지
• /
• 제36권1호
• /
• pp.24-31
• /
• 2003

벼 재배에 있어 이앙기 가뭄시 대체 용수원을 개발하고자 공장폐수처리장(이하 공장폐수 처리수)와 하수종말처리장 방류수(이하 하수처리수)를 관개한 다음 지하 침투수 수질 및 벼생육 변화를 구명하기 위해 본 시험을 수행하였다. 대체 관개 용수원으로서 공장폐수 처리수의 COD, $NH_4{^+}-N$, $Mn^{2+}$, 및 $Ni^+$ 농도와 하수처리수중의 SS및 $PO_4-P$농도는 여러 국가들의 관개 재활용 수질 기준보다 높은 것으로 나타났다. 하수처리수의 초장은 공장폐수 처리수 10일간 관개구를 제외하고 지하수 관개구 보다 약 2 cm 정도 짧았으나, 지하수 및 하수처리수 관개구의 경수는 관개기간에 관개 없이 유의차가 없는 것으로 나타났다. 그리고 하수처리수 및 공장폐수 처리수 20일 관개구의 수확지수는 유의차가 없었지만, 공장폐수 처리수 30일 관개구의 수확지수는 토성에 관계없이 하수처리수 관개구 보다 약간 높은 것으로 나타났다. 공장폐수 처리수 관개구의 토양 침출수중의 SAR값은 하수처리수 관개구보다 2배 이상 높았지만, 하수처리수 관개구는 지하수 관개구와 비교하여 유의차가 없는 것으로 나타났다. 이앙 30일 후 공장폐수 및 하수종말처리수 관개구의 토양침출수중 평균 전기전도도(EC1) 값은 각각 식양토에서 4.7과 $3.4dS\;m^{-1}$ 그리고 사양토에서 3.5 및 $2.5dS\;m^{-1}$로 나타났다. 전생육 기간 및 토성에 따른 공장폐수 처리수 관개구의 토양 침출수중 $EC_i$값이 하수처리수 관개구 보다 2배 이상 높게 나타났지만, 이앙 30일 후부터 급격히 감소하는 경향을 보였다. 그렇지만 하수종말 처리수 관개구의 토양 침출수 중 $EC_i$ 값은 지하수 관개구와 비교하여 유의차가 없는 것으로 나타났다. 이상의 결과로 보아 벼 재배시 하수종말 처리수는 가뭄으로 인한 농업용수가 부족한 경우 대체수자원으로서 잠정적 활용이 가능한 것으로 생각된다.

• Environmental Engineering Research
• /
• 제14권2호
• /
• pp.120-125
• /
• 2009

Water stress has become a major concern in agriculture. Korea suffers from limited agricultural water supply, and wastewater reuse has been recommended as an alternative solution.A study was performed to examine the effects of microorganism concentration in the ponded-water of a paddy rice field with reclaimed-water irrigation for evaluating the microbial risk to farmers and neighborhoodchildren.Most epidemiological studies were performed based on an upland field, and they may not directly applicable to paddy fields. Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion. Their risk value increased significantly high level after irrigation and precipitation.It implies that agricultural activities such as plowing, and fertilizing, and precipitation need be practiced a few days after irrigation considering health risks. The results about field application of the microbial risk assessment using E. coli showed difference according to monitoring time and treatment plot. Result of the microbial risk assessment showed that risk values of ground-water and reclaimed secondary waste water irrigation were lower than directly use of wastewater treatment plants' effluent. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of E. coli to wastewater reuse in a paddy rice farming.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2005년도 학술발표논문집
• /
• pp.661-666
• /
• 2005

Wastewater reuse are exposed public health risk by pathogens. Therefore, this study was examined for microbial risk assessment after irrigation as treated wastewater in paddy rice plots. Five treatments were used: biofilter effluent, UV disinfected water, pond treatment, wetland treatment and conventional irrigation water. Risk assessment was calculated based on the beta-Poisson model by concentration of E. coli from 2003 to 2005. Monte-Carlo simulation (n=10,000) was used to estimate the risk characterization of uncertainty. The risk range was from $10^{-5}$ to $10^{-8}$ except biofilter effluent was $10^{-4}$ in June. The USEPA(1992) has recommended that risk of < $10^{-4}$ is acceptable level of safety for potable waters. In 2005, risk value was lower than 2003, 2004 because of the first irrigation for plowing water is lower E. coli concentration used tap water. It is shown that the first irrigation water quality was important for wastewater irrigation in paddy. UV disinfection and natural treatment used pond and wetland were thought to be an effective for wastewater reuse.

• 한국농공학회논문집
• /
• 제53권1호
• /
• pp.63-69
• /
• 2011

The green algae Scenedesmus acuminatus was cultured in different media: animal wastewater and an artificial culture medium in order to evaluate potential use for tertiary treatment. The experiments were conducted with air flowrate 1~2 L/min at $28{\sim}30^{\circ}C$. The nitrogen and phosphorus showed very similar removal efficiencies (68~77 % and 69~80 % for nitrogen and phosphorus respectively). The optimal fed period was estimated as three days in the semi-continuous experiment. The effects of $CO_2$ (4.5 %) injection on nutrient uptake from animal wastewater (biological treatment effluent) were compared to an air injection under the same conditions of light and photoperiod. The uptake rates of nutrient with air injection were observed 0.009 gN/gChl-a/day, 0.028 gN/gChl-a/day and T-P 0.003 gP/gChl-a/day for nitrate, total nitrogen and phosphorus respectively. The rates were enhanced by addition of $CO_2$ to 0.026 gN/gChl-a/day, 0.076 gN/gChl-a/day and T-P 0.018 gP/gChl-a/day. This study establishes that $CO_2$ addition during nutrient deprivation of microalgal cells may accelerate tertiary wastewater treatment.

• 한국농공학회논문집
• /
• 제52권6호
• /
• pp.19-26
• /
• 2010

Batch experiments were conducted to investigate growth and nutrient removal performance of microalgae Chlorella vulgaris by using piggery wastewater in different concentration of pollutants and the common growth models (logistic, Gompertz and Richards) were applied to compare microalgal growth parameters. Removal of nitrogen (N) and phosphorus (P) by Chlorella vulgaris showed correlation with biomass increase, implying nutrient uptake coupled with microalgae growth. The higher the levels of suspended solids (SS), COD and ammonia nitrogen were in the wastewater, the worse growth of Chlorella vulgaris was observed, showing the occurrence of growth inhibition in higher concentration of those pollutants. The growth parameters were estimated by non-linear regression of three growth curves for comparative analyses. Determination of growth parameters were more accurate with population as a variable than the logarithm of population in terms of R square. Richards model represented better fit comparing with logistic and Gompertz model. However, Richards model showed some complexity and sensitivity in calculation. In the cases tested, both logistic and Gompertz equation were proper to describe the growth of microalgae on piggery wastewater as well as easy to application.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 1998년도 학술발표회 발표논문집
• /
• pp.508-512
• /
• 1998

Recently, biofilm reactors are considered as efficient wastewater treatment system in rural areas, because of characteristics of easy operation and economic feasibility. In order to select the most efficient media, an experimental apparatus with five different media was designed, installed and examined. The media used in this study were zeolite, artificial sponge gourd, absorbent biofilter, non-woven fabric and charcoal. With only one month investigation, all five media showed high removal efficiencies of BOD.