• Environmental Engineering Research
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• 제23권2호
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• pp.195-204
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• 2018

A pilot scale study was conducted on a down-flow hanging sponge (DHS) reactor installed at a sewage treatment plant in Banda Aceh, Indonesia for treatment of desludging septic tank wastewater. Raw wastewater with an average biochemical oxygen demand (BOD) and total suspended solids of 139 mg/L and 191 mg/L, respectively, was pumped into the reactor. Two different hydraulic retention times (HRTs, 3 h and 4 h) were investigated, equivalent to organic loadings of 1.11 and $0.78kg\;BOD/m^3/d$, respectively. The average BOD concentration in the final effluent was 46 and 26 mg/L at HRTs of 3 and 4 h, respectively. The concentration of retained sludge along the reactor height was 10.2-18.7 g VSS/L-sponge, and the sludge activities were 0.24-0.32 and 0.04-0.40 mg/g VSS/h for heterotrophs and nitrification, respectively. Values of water hold-up volume, dispersion coefficient, and number of tank in-series found from tracer studies of clean sponge and biomass-loaded sponge confirmed that growth of retained sludge on the sponge module improved hydraulic performance of the reactor. Adoption of the DHS reactor by this Indonesian sewage treatment plant would enhance the role of the current desludging septic tank wastewater treatment system.

• 공업화학
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• 제33권5호
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• pp.532-537
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• 2022

The need for obtaining treated wastewater that meets high quality standards for discharge or reuse necessitates the use of highly efficient wastewater treatment techniques. In the present study, experiments have been carried out to reduce the concentration level of biological oxygen demand (BOD), chemical oxygen demand (COD), and total dissolved solids (TDS) from the wastewater sample. Treatment of sample of a real municipal wastewater collected from a sewage treatment plant (STP) was carried out in an electrochemical membrane bioreactor (EMBR). The EMBR was operated continuously for five days, and readings were taken at regular intervals. This paper has experimental results conducted in EMBR that indicate reduction of BOD, COD, and TDS levels of up to 32.25%, 29.25%, and 31.93%, respectively. Further, it was observed that a current of magnitude of 0.00752 mA was generated due to the metabolic activities of bacteria present in municipal wastewater, which gradually decreased day by day due to the decay of bacteria.

• 한국농촌건축학회논문집
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• 제2권1호
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• pp.89-100
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• 2000

Recently, according to the increase of population and rapid growth of industry, the amount of effluent pollutant has been rising in natural water. In these pollutant, nutrients such as nitrogen and phosphor are told that these evolve the odor, color and eutrophication in rural housing sewage and lake regulary. Many researches have been carried out to remove these nutrients from effluents and will have to be studied more deeply. Especially, because of the sewage of rural housing and livestock, environmental pollution raises serious problem in a rural community. This method is developed to solve the problem environmentally friendly. Using the natural energy(wasteheat, earthheat, solar engery) and the growth properties of aquatic plants are most efficient method to absorb the nutrients and denitrification and phosphor uptake.

• 대한환경공학회지
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• 제27권3호
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• pp.337-341
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• 2005

It is difficult to use average sewage water quality as a design parameter for the individual sewage wastewater treatment plant(ISWTP), because sewage water quality is very various according to the building use type. So, in this study, we estimated daily, seasonal and weekly trend of sewage water quality and flow rate in various kind of building to comprehend operating state of ISWTP. The sewage water quality and flow rate were higher in the business building than household building. The seasonal difference of the water quality was not detected but that of flow rate was high. The flow rate of the sewage in the business building was higher in summer than in other seasons and in weekend than in weekday. The treatment efficiency of IWSTP was about $70{\sim}80%$ with BOD, $40{\sim}50%$ with TN and TP, which was very low. The unit loads of the individual house were 36.05 gpcd with BOD, 37.91 gpcd with SS, 23.91 gpcd with T-N, and 7.90 gpcd with T-P respectively, and those values were higher than other studies. It is because, as distinct from other studies, sewage water quality was monitored at the inlet point of the IWSTP in this study. We can use this results as an one of basic parameters for the design of IWSTP.

• 상하수도학회지
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• 제27권1호
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• pp.59-67
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• 2013

The odor occurring in the sewage system induces the displeasure, the disgust such as the headache, the vomit, etc. and increases the spiritual stress and disturbs the pleasant life of residents. These odors occur mainly in the area of combined sewage system treatment, being created in the personal sewage treatment plant such as septic tank and are incoming to sewage pipes and emitted to the outside through the manhole and the receiver, etc.; and this causes odors to the people. The Hydrogen Sulfide, the Methyl Mercaptan, the Ammonia, etc. are materials causing the odor, the more serious issue of odor is occurring since the septic tank of degradation process is being applied. The primary cause of odor is the decomposition of human feces in the septic tanks and sewage disposal facilities. The purpose of this study is reduction of hydrogen sulfide using air supplying and SOB(Sulfur-Oxidizing Bacteria). As a result of this study of the air supply system and the SOB media equipment by air supply, in case the air is injected to SOB media compared to the injection of air only, the removal efficiency the hydrogen sulfide was average 3.4 times higher.

• 한국습지학회지
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• 제17권1호
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• pp.11-18
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• 2015

질소에 의한 수질 오염의 심각성이 부각되면서 하 폐수 내 질소제거를 위한 연구가 수행되고 있다. 특히 아질산화 반응을 기반으로 하는 경제적이며 친환경적인 장점을 지닌 혁신적인 질소 제거 공법에 관한 연구가 주목받고 있다. 하지만 아질산화 반응을 기반으로 하는 공법의 현장 적용성 및 효율화 방안에 관한 연구는 완전히 이루어지고 있지 않은 실정이다. 본 연구에서는 하수처리장 유입 하수, 최초 침전지 상등액, 반류수 그리고 가축분뇨의 특성분석 및 실험실 규모 반응조를 운전하였다. 반류수 및 가축분뇨의 경우 다른 하수에 비해 고농도의 질소를 함유한 것으로 나타나 수처리 계통 질소 부하를 증가시키는 것으로 나타났다. 반응조 운전 결과 낮은 암모니아성 질소의 농도로 인해 유입 하수와 최초 침전지 상등액의 경우에는 아질산화 반응이 유도되지 않음을 확인하였다. 또한 하수 종류 별로 아질산화 반응이 유도되는 체류시간 조건이 차이를 보였는데 이는 유기물 및 암모니아성 질소 농도에 의한 것으로 판단된다. 아질산화 반응이 유도된 하수 중 혐기 소화 상등액이 가장 높은 효율을 보이는 것으로 나타났다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_3호
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• pp.97-106
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• 2001

To improve the water quality, particularly for sea bathers, the behaviour of wastewater from sewage outfalls in water adjacent to Swansea, UK, was studied using a mathematical model. The water quality in the sewage receiving basin was determined using factors like the outfall diffuser location(distance from land boundary), sewage treatment scheme, discharge time, and bacteria decay rate, etc. With respect to these factors, an optimal strategy for sewage discharge was then investigated to minimize bacteria levels along the bathing beaches. As water quality criteria, predicted faecal coliform levels were monitored along the coast adjacent to the outfall locations. The resultant values were compared with EC Mandatory(<2000, 95 % of 20 samples) and Guideline Standards(< 100, 80 % of 20 samples). For the advective-diffusion equation, the non linear advective terms were represented using the ULTIMATE algorithm and the third-order accurate QUICKEST scheme to avoid numerical diffusion. Details of the simulation results are then presented as an optimal policy for sewage discharge in the region.

• 상하수도학회지
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• 제19권6호
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• pp.800-808
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• 2005

It is required to propose an alternatives for appropriate sludge treatment owing to persistent construction of sewage treatment plant and increase of sewage sludge quantity. In order to treat sludge more efficiently, the methods which reduce the cost of sludge treatment have been studied such as sludge reduction and conditioning. Especially ozone treatment reduces solid quantity and improves separation of solid-liquid at the same time. Therefore ozone treatment have a positive effect on reduction and stabilization of sludge. So, this study applied ozone to sewage sludge and induced cell destruction of sludge. By comparing with the correlation between thickening and dewatering, and evaluating moisture content and solubilization of cake, this study verificates the effect of process improvement for ozone pre-treatment. In J-STP case, according to ozone dose solid flux increased about 12 times from $1kg/m^2{\cdot}h$ to $12kg/m^2{\cdot}h$. Also this plant were capable to shorten thickening time from 40 minutes to 6~7 minutes. Thus it is expected to reduce volume and retention time of thickener. On pH effect factor, dewatering at pH4 was more than at pH11, $3.05{\times}10^{11}$ and $3.82{\times}10^{11}(m/kg)$. But effect of pH was analogous to ozone, $2.81{\times}10^{11}(m/kg)$. The effect of pH on thickening was similar to law sludge, $0.68(kg/m^2{\cdot}h)$, and the effect of ozone injection on thickening was the biggest, $3.45(kg/m^2{\cdot}h)$. The COD solubilization rate improved from about 5 to 30%. So it is judged that we are able to utilize most solubilized sludge to another sewage treatment plants.

• 한국물환경학회지
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• 제25권5호
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• pp.674-681
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• 2009

Characteristics of organic matters (OM) in wastewater and the removal efficiencies were investigated using the influent and the effluent samples collected from 21 wastewater treatment plants. The OM characteristics investigated included biodegradability, humic content, specific UV absorbance (SUVA), the distribution percentage of refractory OM (R-OM), and synchronous fluorescence spectra. The types of wastewater (sewage, livestock waste/night soils, industrial waste) were easily distinguished by comparing the synchronous fluorescence spectra of the influent wastewater. The prominent peak of protein-like fluorescence (PLF) was observed for livestock waste/night soils whereas sewage exhibited a unique fluorescence peak at a wavelength of 370 nm. Irrespective of the wastewater types, the distribution percentage of R-OM increased from the influent to the effluent. Livestock waste/night soils showed the highest removal efficiency among all the three types of wastewater. There was no statistical difference of the removal efficiency between a traditional activated sludge and biological advanced treatment processes. Removal efficiency based on dissolved organic carbon DOC presented good correlations with the distribution percentage of R-OM and fulvic-like fluorescence (FLF) of the influent. The prediction for DOC removal efficiency was improved by using multiple regression analyses based on some selected OM characteristics and mixed liquid suspended solid (MLSS).

• 상하수도학회지
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• 제27권3호
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• pp.373-382
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• 2013

In this study, a biological odor treatment system was proposed to remove odor(foul smell) materials causing several problems in the closed sewage treatment plant. This odor treatment system was composed of a two-step biofilter system in one reactor. The two-step biofilter reactor was constructed with natural purification layer in upper part and artificial purification layer in lower part. The reed grasses of water purification plants were planted in the surface area and mixed porous ceramic media were filled with the lower part of biofilter reactor. By using the above experimental apparatus, the ammonia gas removal efficiency was attained to 98.3 % and the hydrogen sulfide gas removal efficiency was appeared more than 97.7 % which shows more effective than the conventional odor removal process.