• Journal of Wetlands Research
• /
• v.21 no.3
• /
• pp.244-250
• /
• 2019

Due to the industrial development and population growth, it has recently been shown that there are many problems caused by the rinked treatment water in local goverments and sewage treatment plants. The rinked treatment water has a characteristic of low flow rate and high concentration unlike general sewage. These characteristics increase sewage treatment difficulty and sewage treatment fee of sewage treatment facilities. Among the many influencing factors that increase sewage treatment unit cost, 'linked treatment load/design inflow load (%)' was derived as the most correlated factor. Through the selection and modeling of sewage treatment plants, the excess scope of design discharge water quality was investigated under the conditions of temperature and the conditions of 'linked treatment load/design inflow load (%)' taking into account the effects of the four seasons. The study found that for TN, 'linked treatment load/design inflow load (%)' was 19.7%, 22.6%, 25.1%and 27.7%, respectively, under conditions of $5^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$ and $25^{\circ}C$. In case of TP, 'rinked treatment load/design inflow load (%)' was 10.7%, 12.2%, 15.6% and 17.5% at $5^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$, respectively, under conditions of $5^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$ and $25^{\circ}C$.

• Journal of Wetlands Research
• /
• v.19 no.2
• /
• pp.211-215
• /
• 2017

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.

• Journal of Wetlands Research
• /
• v.22 no.2
• /
• pp.92-99
• /
• 2020

Linked treatment refers to a system that relieves the burden of the business by linking high concentrations of wastewater such as human waste, manure, leachate, and other industrial wastewater to nearby municipal wastewater treatment plants(MWTPs). In 2018, 187 MWTPs, which are about 4.5% of the total domestic MWTPs, have implemented a linked treatment system, but local governments are having difficulties in operating sewage treatment due to lack of reasonable cost estimation standards. Therefore, we proposed an improvement plan to solve the problem in the calculation method that currently imposes linked wastewater. To this end, the effects and correlations of the linkage treatment system on the sewage treatment unit were analyzed, and among them, the main factors with the highest correlation were applied to the improvement plan. As a result, an improvement plan that improved three parts of the existing calculation method was presented, and the calculation method and the calculation case using the existing literature values were also presented. This can be used as a basis for future reference by local governments to implement linkage treatment, and to revise local sewerage ordinance and is believed to be helpful in operating a rational linkage system.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.216-220
• /
• 2012

본 연구는 경기도 용인시에 위치한 공공하수처리장을 대상으로 소수력발전 성능특성을 예측하고 경제성을 분석하여 소수력발전소의 건설타당성을 제시하였다. 방류구에서의 수준측량 조사에 따르면 실제 유효 낙차는 4.3m로 나타났다. 최근 5년간 방류량 자료를 살펴보면 일평균 실제 처리량은 약 $30,000m^3/day$로 나타났으며, 우수 유입과 물 사용량이 증가하는 여름 및 가을에 처리량이 증가하였다. 설계유량은 유량변화에 따른 누적 확률밀도와 유량지속곡선에 근거해 산정하였으며, 시간빈도로 보았을 때 17%의 유량이 지속되는 $0.35m^3/sec$가 설계유량으로 나타났다. 예상되는 수차 발전용량은 11kW급이며, 시스템 가동율은 74%, 그리고 계통선에 송출될 수 있는 연 전력생산량은 71.3MWh로 나타났다. 경제성 평가는 신재생에너지 경제성 분석 도구인 RETScreen 프로그램을 사용하여 B/C ratio, IRR, 개발투자비 등의 경제성 평가지표들을 산정하였다. 편익(Benefit) 산정시 전력기준단가는 133.67원/kWh, 할인율 7%를 적용하였으며, 비용(Cost) 산정시 유지관리비는 초기 건설비의 1%, 사용연한 30년을 적용하였다. 경제성 분석결과 기흥레스피아의 소수력발전소 건설시 초기 건설공사비가 $165,000 일 때, B/C 1.0, NPV $3,534, 투자회수기간 15.1년으로 산정되었고 따라서 초기 건설비용이 $165,000 이하일 때 가장 경제적인 것으로 파악되었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.197-197
• /
• 2019

총인처리시설에서는 응집제를 주입하여 인이나 오염물질을 침전시켜 처리하고 있으며 PAC(poly aluminum chloride)나 $FeCl_3$, $Al_2(SO_4)_3$, 등 다양한 종류의 응집제가 사용되어지고 있다. 하지만 기존에 사용되어 지고 있는 알루미늄계열의 응집제는 처리수에 잔류이온이 존재하게 되어 인체에 축적돼 알츠하이머 병 등 신체질환을 유발할 수 있는 단점이 있다. 따라서 이러한 단점을 사전에 예방하기 위해 $TiCl_4$와 같은 티타늄계열 응집제에 대한 연구가 진행되고 있다. $TiCl_4$ 응집제는 인 제거에 효과적으로 적용할 수 있으며 수중에 잔류이온을 유발하지 않으며 Ti이온은 치과임플란트나 의료장비로 사용될 만큼 인체에 무해하다고 알려져 있다. 응집제 사용에 따라 생성된 응집슬러지의 처리방안에 있어서 기존 응집제의 경우 생성된 슬러지의 대부분은 하수슬러지 위탁처리업체를 통해 소각 및 매립, 재활용 되고 있으나, $TiCl_4$를 응집제로 사용할 경우 생성된 슬러지를 인발하여 건조 및 소성을 통해 이산화티타늄으로 재활용할 수 있어 슬러지를 친환경적으로 처리가 가능해 기존 슬러지 처리방안의 경제적, 환경적 부담을 줄일 수 있는 장점이 있다. 따라서 본 연구에서는 $TiCl_4$를 하수처리장 방류수에 주입하여 수중의 총인(T-P)을 처리한 후 생성된 슬러지를 인발하여 건조와 소성과정을 거쳐 이산화티타늄을 제조하였다. 방류수를 취수해 2.5mg/L의 초기 총인 농도를 가진 원수를 제조하였으며 제조된 원수에 $TiCl_4$를 0.6mL 주입하였을 때 99.93%의 총인제거효율을 얻을 수 있었다. 응집 실험 후 생성된 슬러지를 인발하여 건조 후 $300{\sim}1000^{\circ}C$의 각각 다른 온도조건에서 소성하여 이산화티타늄을 제조하였으며, SEM과 XRD를 통해 제조된 이산화티타늄의 표면특성과 결정성 분석을 실시하였다. 제조된 이산화티타늄은 $500{\sim}800^{\circ}C$에서는 아나타제, $900{\sim}1000^{\circ}C$에서는 루타일 결정구조가 나타났다. 또한, $TiCl_4$ 주입량에 따른 이산화티타늄의 최종 생산량과 제조 시 사용되는 건조로 및 소성로의 경제적 비용 등을 고려하여 이산화티타늄 1Ton을 제조하기 위해 필요한 단가를 산출하였다. 본 연구에서 제조된 이산화티타늄 1kg의 생산단가는 약 5,400원으로 나타났으며, 가장 많이 사용되는 P-25 광촉매 보다 저렴한 가격으로 제조 및 판매를 기대할 수 있다. 따라서 하수처리장에 적용 시 기존 응집제 보다 비싼 $TiCl_4$ 비용을 보완하고 친환경적인 슬러지 처리로 제조된 이산화티타늄의 유통 및 현장적용을 통해 경제적, 환경적으로 우수하다고 판단된다.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.6 no.2
• /
• pp.45-57
• /
• 1998

The object of this experiment was to determine the optimum mixing ratio of paper mill sludge and sewage sludge with woodchips as a bulking agent. The bulking agent was mixed with the mixture of paper mill sludge and sewage sludge(2:1 by dried weight) at the rates of 0(W-0), 20(W-20), 33(W-33), and 50(W-50)% on volume basis, and then the mixtures were composted by forced aerated static pile. The changes of physicochemical properties of the mixtures were measured during the composting in order to evaluate the maturity of composts. The temperatures of W-30 and W-50 treatments increased rapidly as soon as the composting started, and reached $60^{\circ}C$ in the fifth day of composting. Reduction of hot water soluble C/N ratio of W-33 and W-50 treatments showed faster than that of W-0 and W-20 treatments at early stage of the composting. The contents of hot water soluble $NO_3{^-}-N$ showed little change in the early stage of the composting in all treatments, but increased rapidly after 20 days of the composting, and the contents of W-0 among all treatments were lower than the others. The G.I. values of W-50 treatment were over 80 before 20 days after starting the composting, those of W-0 treatment were over 80 after 30 days. As a result of evaluation of compost, W-33 and W-50 treatments were found very reasonable at the mixing ratio of a bulking agent. But it is very difficult to aerate compost pile for W-50 treatment than W-33 treatment due to intensified fluctuation of temperature. Considering cost, availability of a bulking agent, and productivity of compost, W-33 treatments more efficient than W-50 treatment.