In this research, the target process was a modified type of a conventional aeration tank with four different influent feeding points and alternated aeration to obtain nitrogen removal. For more accurate switching of influent feeding, the process was operated under a designed control strategy based on monitoring of NH4-N and NOX-N concentrations in the tank. However, the strategy did have some limitations. For example, it was not sensitive to detecting the end of each reaction when losing the balance between nitrification and denitrification of each opposite part of biological tank. To overcome the limitations of the existing control strategy, a diagnosis-based control strategy was suggested in this research using the diagnosis results classified as normal (N), ammonia accumulation (AA) and nitrate accumulation (NA). Using the pre-designed rules for control actions, the aeration and volume of the aerated part of the reactor could be increased or decreased at a fixed mode time. In simulations of the suggested diagnosis-based control strategy, the NH4-N and NOX-N removal rates in the reactor were maintained at higher levels than those of the existing control strategy.

인구의 증가와 산업화는 돼지, 소, 닭 등의 육류 식품의 급격한 수요증가를 초래하여 축산폐수발생량 역시 증가하였다. 2012년 해양투기의 법적 금지는 축산폐수 발생량을 173,304m3/day에 이르게 하였고 지속적인 증가추세에 있다(2016, 환경부). 축산폐수는 고농도의 질소, 인, 유기물을 포함하므로 수계 노출 시 부영양화를 유발하여 인간의 생활과 보건에 혼란과 악영향을 초래한다. 이러한 문제해결을 위해 혐기성 생물공학기술, 화학적 산화기술 등이 적용되어 왔으나 고부하에 취약하고 높은 비용을 요구하는 한계를 지닌다. 최근 새로운 대안으로 미세조류를 활용한 처리방법이 주목받고 있는데, 그 이유는 광독립영양 성장을 하는 미세조류의 특성상 빛에서 에너지를 얻어 경제적으로 지속가능하고 CO2를 탄소원으로 이용하여 탄소중립적으로 폐수 내의 고농도의 질소와 인을 동시에 처리할 수 있기 때문이다. 따라서 본 연구는 축산폐수내의 고농도의 유기물 및 영양염류를 동시에 가장 효과적으로 제거 가능한 미세조류를 문헌조사하여 대상 미세조류의 적용 타당성을 평가하였고, 최적 종을 선정하기 위한 성능평가 및 성장저해 분석을 수행하였다. 문헌조사를 통해 선정된 Scenedesums quadricauda, Scenedesums obliquus, Chlorella sorokiniana 을 28℃ 인큐베이터에서 500mL bottle의 용량으로 Phototrophic 조건(연속 빛조사)과 Mixotrophic 조건(16hr light-8hr dark 주기 반복)으로 Batch test를 진행하였고 그 결과를 성장 동역학적으로 해석하여 최적 종을 제시하였다. 실험은 BG-11을 대조구(Control)로 하여 미세조류의 cell counting결과를 바탕으로 비성장률(specific growth rate)을 도출한 결과 0.293 hr-1 (Scenedesums quadricauda), 0.302 hr-1(Scenedesums obliquus), 0.243 hr-1(Chlorella sorokiniana) 로 밝혀져 Scenedesums obliquus 가 가장 빠른 성장속도를 보였고, 축산폐수를 원수, 2배, 5배, 10배 희석을 하여 미세조류를 배양했을 때에도 최적의 유기물 및 영양염류 제거가 가능함을 보였다. 본 연구는 최적미세조류를 활용한 축산폐수 처리가 저에너지를 사용하며 기후변화에 대응하고 지속가능한 고농도 축산폐수처리 방법이 될 수 있음을 입증 하였다.

The purpose of this study was to confirm the applicability of aerobic granular sludge (AGS) in the advanced sewage treatment process. Simulated influent was used in the operation of a laboratory scale reactor. The operation time of one cycle was 4 h and the reactor was operated for six cycles per day. The volume exchange ratio was 50%. The influent was injected in divisions of 25% to increase the removal efficiency of nitrogen in every cycle. As a result, the removal efficiencies of CODCr and TN in this reactor were 98.2% and 76.7% respectively. During the operation period, the AGS/MLVSS concentration ratio increased from 70.0% to 86.7%, and the average SVI30 was 67 mL/g. The SNR and SDNR were 0.073 0.161 kg NH4 +-N/kg MLVSS/day and 0.071 0.196 kg NO3 --N/kg MLVSS/day respectively. These values were higher or similar to those reported in other studies. The operation time of the process using AGS is shorter than that of the conventional activated sludge process. Hence, this process can replace the activated sludge process.

최근 도시 인구의 증가에 따라 하수 및 분뇨 발생량이 증가하고 있으며, 다양한 오염원으로부터 유입되는 하수에는 질병을 유발할 수 있는 다양한 병원성 미생물이 존재한다고 알려져 있다. 하수처리를 위한 다양한 공정에서는 미생물을 포함하고 있는 bioaerosol이 발생할 수 있으며, 하수 및 분뇨에 포함된 병원성 박테리라 등을 포함하고 있을 가능성이 높다. 따라서 호흡을 통해 하수처리장의 근무자 및 주변 주민에게 위해를 가할 수 있으므로, bioaerosol의 발생 특성 및 감소에 관한 연구가 필요한 현실이다. 하수처리공정 중 bioaerosol이 발생하는 대표적인 환경으로는 활성 슬러지 공정이 있으며, 폭기조에서의 대량 폭기로 인한 높은 농도의 bioaerosol이 발생한다고 알려져 있다. 최근에는 기존의 재래식 활성슬러지 공정(CAS, Conventional Activated Sludge)보다 소요 면적이 적고, 고농도의 미생물 농도를 유지하고 있어 수질 처리 효율이 좋은 호기성 MBR(Membrane bioreactor)의 사용이 증대되고 있다. 그러나 호기성 MBR은 고농도의 미생물 농도 유지 및 멤브레인의 파울링 감소를 위해서는 많은 양의 공기 폭기를 유지해야하므로, 상대적으로 높은 농도의 bioaerosol의 발생이 한정된 공간에서 이루어질 것으로 예상된다. 호기성 MBR의 특성상 운전 조건에 따라서 반응기 내 미생물의 농도 및 특성이 달라질 것이며, 이에 따라 bioaerosol의 발생량 및 특성도 영향을 받을 것으로 예상된다. 그러나 국내에서는 하수처리 과정 중 호기성 MBR 공정에서의 bioaerosol 발생에 관한 연구가 전무하며, 이에 대한 기초 연구 및 발생량 감소를 위한 연구가 미흡한 실정이다. 본 연구에서는 하수처리장 MBR 공정에서 운전 조건에 따른 반응기 내 미생물 농도 및 특성을 확인하고, bioaerosol 발생량을 비교하고자 하였다. 더불어 bioaerosol 발생량을 저감할 수 있는 방안에 대한 연구를 추가적으로 진행하고자 하였다.

상향류식 혐기성 생물전기화학 반응조(upflow anaerobic bioelectrochemical reactor, UABE)를 이용하여 주정폐수를 유기물부하율 16 g COD/L.d에서 처리하는 동안 pH, 알카리도, 유기산 등의 상태변수들의 변화와 COD 제거율, 비메탄발생량 및 메탄함량에 대한 전극배치의 영향을 평가하였으며, 그 성능을 UASB 반응조와 비교하였다. 면적이 27 m²/m³인 전극을 나선형으로 UABE 반응조 전체 공간에 고르게 배치하였을 때 비메탄발생율은 5.78 L/L.d로서, 전극을 설치하지 않은 UASB 반응조의 3.49 L/L.d보다 약 65.6%로 높았다. 이것은 UABE 반응조에 전기활성미생물이 성장하여 직접 종간전자전달(direct interspecies electron transfer, DIET) 반응이 활성화됨으로서 메탄생성반응이 크게 향상되었다는 것을 의미한다. UABE 반응조의 상부 1/3의 공간에 위치한 전극을 제거하였을 때, 비메탄발생율은 5.74 L/L.d로서 반응조 전체 공간에 전극을 설치한 경우와 큰 차이가 없으나, UABE 반응조 상부 2/3 공간에 설치한 전극을 제거한 경우 비메탄발생율은 5.34 L/L.d로 약 7.5% 감소하였다. 이 결과는 UABE 반응조에서 전극을 하부 1/3의 공간에만 설치한 경우 전기활성미생물도 감소하여 DIET 반응도 감소하였다는 것을 의미한다. 전극을 UABE 반응조 하부로부터 2/3 이상의 공간까지 설치하였을 때 COD 제거율은 약 91.5%이었으나 반응조 하부로부터 1/3의 공간에만 설치한 경우 COD 제거율은 88.9%로 약 2.6%로 감소하였다.

현재 국내에서 발생하는 음폐수의 해양투기 금지와 음식물류 폐기물의 에너지화 정책에 따라 유기성 폐기물의 혐기소화를 통한 바이오가스화 시설이 지속적으로 설치 및 운영되고 있다. 그동안 많은 연구와 운영 경험을 통해 유기성 폐기물의 바이오가스화 공정은 점차적으로 안정화되어 가고 있는 가운데, 해당 시설에서 발생하는 혐기소화여액에 대한 적정 처리가 전체 시설의 경제성에 큰 영향을 미치고 있다. 해외, 특히 유럽에서는 유기성 폐기물의 혐기소화여액을 대부분 퇴비 또는 비료로 활용하고 있으나 국내에서는 경작 면적 및 시비 시기 등에 대한 제약으로 인해 해외의 경우처럼 혐기소화여액을 퇴비 및 비료로 활용하는데 한계를 가지고 있다. 이에 대다수의 국내 음식물류 폐기물 바이오가스화 시설에서는 혐기소화여액을 별도의 폐수처리 후 하수처리장에 연계 처리하고 있으며, 고형물인 탈수케익은 일부 퇴비원료로 생산하고 있으나 이에 대한 수요 및 구매 매력도가 떨어져 무상공급 또는 유상처리하고 있는 실정이다. 이에 따라 탈수케익을 퇴비원료로 생산하는 대신 매립 또는 소각 처리로 전환하는 시설도 늘어나고 있다. 또한, 음식물류 폐기물의 혐기소화여액은 높은 질소 농도로 인해 하수처리장 연계수질에 따라 단순 응집침전부터 다단 고도처리까지 적용하여 처리하고 있어, 본 과제에서는 국내 음식물류 폐기물 바이오가스화 시설을 직접 방문 조사하여 각 시설의 폐수처리공정 성능 및 애로사항 파악을 통해 주요 연계수질 기준에 따른 최적 폐수처리공정 선정 Guideline을 도출하고자 하였다.

In this study, content and leaching tests of heavy metals (14 items) were analyzed to evaluate the recyclability of the sludge from wastewater treatment facilities. Additionally, this was compared with and examined with the standard of controlled waste, certification standards of compost materials, etc. In the results of the content test, Cr6+ (30.82 mg/kg) of waste from the leather, fur, and textile industries (EWC 04) and Cr6+ (103.13 mg/kg) of waste from the manufacture formulation, supply, and use of coatings (EWC 08) were higher than the proposed criteria of Cr6+ (20 mg/kg). The high level of Cr6+ concentration was observed because of the use of sodium dichromate and chromic anhydride in the materials of dyestuffs and pigments and ink in the EWC 04 and EWC 08 processes. The results on sludge in this study did not meet the standard of the Fertilizer Control Act and quality standard of fuels. In particular, the high levels of Pb and Cd was the main reason.

The aim of this study was to investigate the nutrient removal using Mg-Sericite flocculant in the dyeing wastewater. Mg-Sericite flocculant was removed successfully > 98% of the Color, SS. COD and BOD in the dyeing wastewater at the following optimal Mg-Sericite dosage: 100 mg/L for Colour and SS, 300 mg/L for BOD and COD. The removal of TN and TP was obtained 92.00% with 50 mg/L and 87.80% with 100 mg/L Mg-Sericite dosage, respectively. These results was indicated that the amount of 0.79~1.31, 0.22~0.37, 0.5 and 0.16 mg/L Mg-Sericite was necessary for 1 mg/L removal BOD, COD, TN and TP, respectively. The biopolymer, Mg-Sericite, can be a promising flocculants due to its high efficiency and low dose requirements. In addition, Mg-Sericite does not contaminate treated wastewater, which can be recycled to reduce not only the cost and the demand for water but also the extra operational costs for reusing wastewater. This flocculation method is helpful to lower the wastewater treatment cost.

This study of the electrolysis reaction fillers and electrolytic treatment sludge generated by checking the status and properties of the sludge before and after electrolysis filler caused by a reaction to examine the water-soluble cutting oil sludge and organic matter removal mechanism of filling in the packed bed bipolar electrolytic reactor was to identify the characteristics. Delivery was analyzed using a SEM (scanning electron microscope) recording method for the filling material in the GAC surface characterization of the packed bed bipolar electrolytic reactor to look at the reaction of the waste water generated by the electrolytic removal reaction. Sludge generated in order to analyze the properties of XRD(x-ray diffraction) was analyzed using the device. The video of the GAC surface before and after the reaction was taken by SEM, it can be known indirectly the change between the voids in the GAC in figure before and after. Prior to the electrolytic treatment can be seen that there is some contamination between the pores, but it can be seen that after the treatment, rather than clean the pores of the GAC. This photograph of the surface after the electrolytic treatment, GAC is decomposed organic material adsorbed on the surface by dissolution of ions at the anode acting on bipolar electrolytic, it is corroded, it is possible to observe what happens. It was found to form iron oxide when analyzing the electrolytic sludge using XRD. Properties of the sludge generated after electrolysis, was composed primarily of oxygen and iron. These results wastewater treatment by filling in the electrolytic cell is that it indirectly proves to occur by electrolysis removal, it is considered to be able to demonstrate the deletion mechanism indirectly.

Livestock Wastewater shall cause a high concentration of organic matter and nutrients such as rivers because of the lake and groundwater contamination, such as the accumulation of nutrients in the soil contained in the manure, livestock wastewater containing large amounts of organic matter that will flow to the river or appeal If eutrophication, and comfortable living environment to cause harm, such as odor and pest damage and can. Organic waste and organic waste, such as the world has a direct interest in acquiring the available resources and the development of clean energy from waste is a growing desire, is expected to contribute to the environment from waste materials industry growth by developing innovative technologies such as direct electrical energy production. In the case of livestock waste water and high concentration of organic material in addition to containing ammonia nitrogen, nitrate nitrogen for nitrification is created due to the electron acceptor is used as the fuel cell according to this has been reported to decrease the efficiency of electricity production. Therefore, to derive the electricity production efficiency due to organic concentration and ammonia nitrogen concentration in order to apply a microbial fuel cell (MFC) livestock wastewater treatment process in this study, and to derive the energy production potential with livestock waste water through the study. Lab. scale Reactor fabrication and operation to try to derive the reaction factor of the optimum operating conditions in accordance with the livestock wastewater applied through the evaluation of trends and removal efficiency of organic matter and nutrients in the microbial fuel cell. In addition, from the final research results, I try to present the direction of future research for the improvement of application possibilities and microbial fuel cell power generation efficiency of microbial fuel cell in the livestock wastewater treatment facilities.

Greenhouse gas (GHG) emissions from dye wastewater treatment processes were estimated by analysing their mass and energy balances, which were then used as baseline information for environmental assessment. The total GHG emissions from dye wastewater treatment plants were divided into direct emissions from the treatment processes and indirect ones from electricity usage. The amounts of CO2, CH4 and N2O emissions were calculated according to the Intergovernmental Panel on Clime Change (IPCC) guideline for the GHG target management system. For 3 years between 2011 and 2013, direct and indirect emissions were on average 8,742.7 and 7,892.0 Ton.CO2eq/year, respectively, with the former exhibiting 52.6 %. Also, compared to 2012, in 2013, the eco-efficiency indicator by the GHG emissions was found to be more than 1, suggesting that environmental quality was effectively improved.

The aim of this paper is to compare the characteristics of the T-P removal from synthesized municipal wastewater by electro-coagulation using cylindrical Al and Fe electrode as anode. For this purpose, a concentric circle type electrolysis reactor was used and the operating conditions for T-P removal from synthesized wastewater are as follows; potential 10 V, electrolyte 0.03% NaCl, initial T-P concentration 1.0 ~ 6.0 mg/L and flow rate 1.0 ~ 5.0 L/min. From the experimental results, T-P concentration of treated wastewater was decreased to less than 0.2 mg/L enough to discharge standard and Al electrode showed performance than Fe electrode for T-P removal by electro-coagulation. Optimal conditions for T-P removal to less than 0.15 mg/L which is 75% of discharge standard for large scale municipal wastewater plant (capacity higher than 500 m3/day) were obtained as follows; flow rate 2.503 L/min, and 2.337 L/min, HRT 1.059 min, 1.134 min, for Al and Fe electrode, respectively. Consumed mass of Al and Fe were of 3.76 times and 8.90 times respectively, were obtained to removed T-P at optimal conditions with potential 10 V, and 0.03% NaCl as electrolyte.

도계량을 현재의 2배까지 증가시킬 예정인 닭 가공 업체인 A사의 생물학적 처리조를 대상으로 하여 처리효율을 2배까지 높이는 방안을 모색하였다. 이를 위해 MLSS 농도가 증가할 경우 이에 따른 유기물 및 질소 제거 효율 증가에 대한 근거를 확보하고자 연구를 진행하였다. 연구는 닭 가공 폐수를 1차 화학 처리한 가압부상처리수를 대상으로 진행되었으며 SBR 형태로 진행되어 호기조 상태 25시간 운전 후, 무산소조 상태 5시간으로 운전되었다. MLSS 12,700mg/L로 진행된 실험 결과 호기조 상태 25시간 이내에 질산화가 완벽하게 일어났으며 C/N비 3:1 이상 실험군에서의 탈질 효율도 90%를 초과하였다. 후에 진행된 MLSS 농도 대비 유기물 및 질소 제거 효율 비교에서는 MLSS 농도를 5,600에서 12,700mg/L까지 변화시켰으며 MLSS 농도 10,800mg/L 실험군에서 유기물과 총 질소 농도 모두 배출허용기준치를 만족하는 결과를 보였다.

To treat chromaticity contained in effluents of dyeing wastewater efficiently, potent dye-degrading microorganisms were isolated from influent water, aeration- tank sludge, recycle water and settling-tank sludge located in leather and dyeing treatment plant. Six potent strains were finally isolated and identified as Comamonas testosteroni, Methylobacteriaceae bacterium, Stenotrophomonas sp., Kluyveromyces fragilis, Ascomycetes sp. and Basidiomycetes sp. When Basidiomycetes sp. was inoculated into ME medium containing basal mixed-dyes, 93% of color was removed after 8 days incubation. In the same experiment, the 1:1 mixed culture of Basidiomycetes sp. and photosynthetic bacterium exhibited 88% of color removal; however, it showed better color removal for single-color dyes. The aeration-tank and settling-tank samples revealed higher color removal (95-96%) for black dyes. The settling-tank sample also revealed higher color removal on basal mixed-dyes, which resulted in 90% color removal after 6-h incubation. From the above results, it is expected to achieve a higher color removal using the mixed microorganisms that were isolated from aeration-tank and settling-tank samples.

As an alternative for energy intensive aerobic wastewater treatment system, development of sulfate reducing bacteria (SRB)-based domestic wastewater treatment system was researched. No requirement of aeration, fast substrate utilization and less sensitiveness of SRB are main factors for energy conservative wastewater treatment system. Sulfate for SRB’s synthesis could be supplied from SOx in industrial gas, thus the system also can contribute to the economical treatment of hazardous sulfur compound in the gas. With the dissolved sulfate as an electron acceptor, SRB degrade organic matters in wastewater and produce sulfide. This produced sulfide was used for electricity generation in sulfide fuel cell system connected to continuously operating UASB reactor. This study also focused on obtaining SRB dominant granule from methanogen dominant anaerobic granule in a competition between SRB and methanogens. As a strategy to increase SRB activity and to suppress methanogens, starvation was applied by not providing organic source but continuous supplying sulfate. Based on the well adopted hypothesis on the granule structure, methanogens located relatively inner core of a granule died out due to the lack of organic source, while SRB located at outer part of granule survived utilizing extracellular polymeric substance (EPS) or organic matters from died out microbes as an organic source. By eliminating the competition, the portion of organic matter degradation by SRB was increased from 19% before starvation to 93% after starvation, achieving 80% COD removal in total. In case of sulfate removal, 15% improvement was achieved compared to the control reactor. This effect of starvation on the granule characteristics were confirmed with scanning electron microscope (SEM) and transmission electron microscope (TEM). Not only wastewater treatment by SRB but also electricity generation with sulfide fuel cell system was studied. Several sets of batch tests were conducted and continuous operation was also carried out with effluent containing 80mg/L -100mg/L sulfide. Through the batch tests, hydraulic retention time (HRT) was optimized to 8 h, removing almost all of the sulfide from the effluent, having the highest power density of 0.033 mW/cm². With the optimized HRT, sulfide fuel cell connected to the UASBr was continuously operated for over 50 days. This newly developed wastewater treatment system with SRB integrated with electricity generating sulfide fuel cell system is believed to be a promising technology for more sustainable wastewater treatment system.

The effect of temperature on the removal process of Cr(VI) ion contained in wastewater by a precipitation method has been investigated for the improvement of its design and operation. The distribution diagram of chromium ion was constructed by employing the MINTEQ program and the quantitative feature of Cr(VI) depending on pH was investigated. As the temperature increases, the relative amount of H2CrO4 was examined to be raised and the pH range in which H2CrO4 exists as a stable form was also investigated to be extended according to the temperature. Cr(VI) ion was shown to be changed from HCrO4 − to Cr2O7 2− as the concentration of Cr(VI) ion is increased in the neutral pH condition and the concentration of Cr(VI) ion which is necessary for the ionic transformation was observed to rise in the acidic and alkaline conditions. The major reactant which involved in the reduction reaction for the removal of Cr(VI) ion was examined to be HCrO4 − and the reduction of Cr(VI) ion to Cr(III) ion was investigated to be influenced much by the temperature change at higher pH conditions. The reduction reaction of Cr(VI) ion for its removal as a precipitate was examined to be promoted as the temperature decreases and pH is lowered. In addition, the stable region of Cr(OH)3 was shown to be enlarged with temperature based on the thermodynamic estimation and it was thought to be necessary to design and control the precipitating process of Cr(VI) ion by considering the thermal characteristics of reduction and precipitation stage.

This paper presents the results of the electrochemical treatment of chemical oxygen demand(COD) and total nitrogen(T-N) compounds in the wastewater generated from flue gas desulfurization process by using a lab-scale electrolyzer. With the increase in the applied current from 0.6 Ah/L to 1.2 Ah/L, the COD removal efficiency rapidly increases from 74.5% to 96%, and the T-N removal efficiency slightly increases from 37.2% to 44.9%. Therefore, it is expected that an electrochemical treatment technique will be able to decrease the amount of chemicals used for reducing the COD and T-N in wastewater of the desulfurization process compared to the conventional chemical treatment technique.