• Membrane and Water Treatment
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• 제10권3호
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• pp.191-199
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• 2019

In this study, we investigated the cultivation possibility using Hydrodictyon reticulatum in a continuous raceway pond as a tertiary sewage treatment plant. The cultivation possibility was evaluated by varying the light quantity, wavelength, and hydraulic retention time (HRT). Experimental results showed that the growth rates of algae and the removal efficiencies of nutrients increased as the light quantity increased, and the maximum photosynthetic rate was maintained at $100{\mu}mol/m^2{\cdot}s$ or higher. When wavelength was varied, nutrient removal efficiency and growth rate increased in the following order: green light, red light, white light, and blue light. The nutrient removal efficiencies and algae productivity in HRT 4 d were better than in HRT 8 d. We conclude that if Hydrodictyon reticulatum is cultivated in a raceway pond and used as a tertiary treatment facility in a sewage treatment plant, nutrients can be effectively removed, and production costs can be reduced.

• 대한환경공학회지
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• 제35권10호
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• pp.694-702
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• 2013

본 연구의 목적은 이차침전조의 구조개선을 통해 탈수여액 처리와 생물학적 처리용량 확보의 가능성을 평가하는데 있다. 이에 따른 연구의 절차로는 탈수여액 내 함유된 polymer가 슬러지 침전에 미치는 영향을 column test를 통해 평가하였으며, 회분식 실험과 연속식 처리공정운전을 통해 탈수여액의 처리 특성을 평가하였다. 그 결과 슬러지 침강속도는 polymer 주입율이 증가할 수 록 증가하는 경향을 나타냈으며, 상징수의 SS 농도는 감소하는 것을 알 수 있었다. 탈수여액의 처리 특성은 이차침전조 내통 길이가 길수록 탈수여액 내 함유된 TSS 및 TBOD5의 제거효율이 증가하는 경향을 보였다. 또한 연속식 처리공정 적용 결과는 탈수여액 주입위치를 각각 무산소조와 이차침전조에 주입한 경우를 비교하였을 때 두 조건에서 모두 안정적인 방류수질을 보였다. 따라서 이차침전조의 구조개선을 통해 탈수여액의 효율적인 처리가 가능 할 것으로 판단되며, 소규모 하수처리장의 경우 처리용량 부족 문제를 해결할 수 있을 것으로 사료된다.

• Environmental Engineering Research
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• 제15권3호
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• pp.163-166
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• 2010

Pulp and paper mill wastewater has been treated by biological treatment, but the secondary effluent still contains high lignin, chemical oxygen demand, color and total dissolved solids. Tertiary treatment by land application, referred to as 'Project Green,' has been implemented to treat such high quantities of undesirable matters. The impacts of seepage from Project Green diffusing into receiving streams on the water quality and fish pen aquaculture were studied via the integration of technical and social approaches. The determination of the water quality was performed for 13 sampling stations along the receiving stream, including the Chot stream, Chot lagoon and the Pong River. The water quality was generally at normal levels, with the exception of total dissolved solids. The levels of matter were higher at the Chot stream, but became more diluted at the Chot lagoon and the Pong River, respectively. The social approach was conducted through the voluntary participation of the villagers as research assistants for the fish aquaculture study. Fish could grow at three fish pens within the study sites at the location of Project Green, the Chot lagoon and the Pong River. Fish growth at the Chot lagoon was better at the site of Project Green and the Pong River. The integration of technical and social approaches was a meaningful tool not only for the technical feasibility but in helping to solve the conflict between the community and industry.

• 한국환경농학회지
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• 제20권4호
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• pp.277-283
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• 2001

This paper presents treatment efficiency and plant growth of a surface-flow constructed wetland system (30 meter in length and 10 meter in width) over one year after its establishment on a floodplain of a stream. Cattails (Typha angustiflora) grown on pots were transplanted on one half of its area from inlets and reeds (Phragmites australis) on another half from an outlet. Effluent discharged from a secondary-level treatment plant was funneled into the system. The stems of cattails and reeds emerging in April 2001 grew up to 165.9 cm and 95.3 cm, respectively until July 2001. The number of stems of cattails arid reeds in July 2001 increased by 65% and 100%, respectively, compared with that just after their planting. The growth of cattails was better than that of reeds during study period. The removal rates for SS, $BOD_5$, T-N and T-P was 33%, 43%, 31%, and 51%, respectively. The system was inundated seven times by storms over the monitoring period, which disturbed its environment and led to its lower treatment rates. The increase of SS concentration in effluent after inundation of the system was attributed to the falls of soil particles onto its water surface, which had been attached to the emergent plants by floods. Purification rates for T-N were relatively low for the period of late fall through winter until early spring due to lower water temperature which may have retarded microbial nitrification and denitrification mechanisms. Reduction in T-P concentration during fall and winter was relatively higher than that during summer and spring, which may have resulted from no system perturbations by floods and heavy storms during fall and winter.

• Environmental Engineering Research
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• 제15권2호
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• pp.79-84
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• 2010

Three biological aerated filters (BAFs) composed of a PVC pipe with a diameter of 75 mm were constructed and operated at a waste-water temperature at $13^{\circ}C$. The media used for each BAF were: 5-mm gravel; 5-mm lava rock; 12.5-mm diameter by 15-mm long plastic rings, all with a media depth of 1.7 m. The feedwater, which simulated the effluent of aerated lagoons, had influent soluble chemical oxygen demand (sCOD) and ammonia concentrations of approximately 50 and 25 mg/L, respectively. For a hydraulic retention time (HRT) of two hours without recirculation, ammonia percent removals were 98.5, 98.9, and 97.8%, for the gravel, lava rock, and plastic rings, respectively. By increasing the effluent recirculation from 100 to 200% for an HRT of one hour, respective ammonia removals improved from 90.1 to 96, 76.5 to 90, and 65.3 to 79.5% for gravel, lava rock, and plastic rings. Based on the ammonia and sCOD loadings for different HRTs, the estimated maximum ammonia loading was approximately 0.6 kg $NH_3-N/m^3$-day for the three BAFs of different media types. The zero-order biotransformation rates for the BAF with gravel were found to be higher than the lava rock and plastic ring media. The results ultimately showed that BAF can be used as an add-on system to aerated lagoons or as a secondary treatment unit to meet ammonia discharge limits.

• 한국항해항만학회지
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• 제28권3호
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• pp.259-268
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• 2004

지난 몇 년 동안, 해안지역에서 산업의 발달과 인구증가로 인해서 육지에서 방출되는 오폐수의 정화 처리 방법이 중요한 문제점으로 지적되고 있다. 처리방법으로는, 1차 처리 또는 2차 처리된 것을 수중 방류관을 통해 해안이나 심해 또는, 그 중간지점에서 방출되는데, 오폐수가 방출되면 주변의 해수를 연행하여 플룸, 제트 또는 부양성 제트의 형태로 해수면까지 상승하면서 많이 희석된다. 본 연구는 해양환경관리 및 오폐수 처리에 관한 의사결정과정에서 중요한 해양방류관 설계를 다룬다. Cormix 모델에 조위의 변화와 계절변화에 의한 몇가지 요소를 고려하여 방류수의 궤적과 희석을 다룬다. 본 연구는 방류수의 효과석인 관리를 위한 기본 데이터와 일반배치에 매우 유용하게 활용될 것이다.

• 한국물환경학회지
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• 제33권4호
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• pp.403-408
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• 2017

In these days, wastewater reclamation and seawater desalination play essential role in addressing the challenge of worldwide water scarcity. Particularly, reverse osmosis (RO) for seawater desalination process is commonly used due to less energy consumption than conventional thermodynamic systems. However, membrane fouling and electrical energy consumption during operation of RO system for seawater desalination haver continued to be a obstruction to its application. In this study, therefore, wastewater secondary effluent is used for osmotic dilution of seawater. Firstly, fouling behaviour of RO by simulating wastewater effluent in osmotic dilution process was measured and we calculated energy consumption of overall desalination process by theoretical equations and commercial program. Our results reveal that RO membrane fouling can be efficiently controlled by pre-treatment systems such as nano filtration (NF) or forward osmosis (FO) process. Especially FO system for osmotic dilution process is a non-pressurized membrane system and, therefore, the operating energy consumption of overall desalination system was the lowest. Moreover, fouling layer on FO membrane is comparatively weak and reversible enough to be disrupted by physical cleaning. Thus, RO system with low salinity feed water through FO process is possible as a less energy consuming desalination system with efficient membrane fouling control.

• 한국물환경학회지
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• 제22권1호
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• pp.51-58
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• 2006

The effluent limitations for individual industry based on the best available technology economically achievable (BAT) have been required to achieve effective regulation. BAT assessment criteria that are suitable for the circumstances of Korean industry were developed in the previous study. The criteria were applied to determine the BAT for leather tanning and finishing industry. For the evaluation BAT, a subcategorization for the industry considering wastewater characteristics, source equipments, raw material and so on should be suggested. Three subcategories: A) Unharing, Chrome Tan, Retan-Wet Finish, B) Chrome Tan, Retan-Wet Finish, and C) Furskins were proposed in this study. Wastewater discharged from the each category contains high concentration of COD, chrome, nitrogen and sulfide. In particular, the concentration of nitrogen from the subcategory A is significantly greater. Twenty sites were surveyed and wastewater qualities were analyzed. Therefore, six different technologies were applied to the subcategory A for the end-of-pipe treatment technology, and a technology was used in the subcategory B and C, respectively. The technology candidates were evaluated in terms of environmental impacts, economically achievability, treatment performance and economical reasonability. As the result, the technology options for each subcategories: A) primary chemical precipitation + modified Ludzack-Ettinger process (MLE) + secondary chemical precipitation, B) chemical precipitation + typical activated-sludge process + Fenton oxidation, C) chemical precipitation + typical activated-sludge process + batch Fenton oxidation or batch activated carbon treatment were selected as the BAT, respectively.

• 생태와환경
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• 제36권3호통권104호
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• pp.356-368
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• 2003

본 연구에서는 국제적으로 사용하고 있는 농업용수 재이용 수질기준을 검토하고 우리나라 하수처리 방류수의 재이용 가능성에 대하여 고찰하였으며, 재이용수로이용하기 위해 필요한 처리대안에 실험 ${\cdot}$ 연구한 결과이다. Biofilter 유출수를 17, 25, 40W의 3가지 램프로 UV소독한 결과 40W 램프에서는 모든 경우에 100%소독되었으며, 25 W와 17 W에서는 전반적으로 97%이상 소독효율을 나타내었으며, 적절하게 설계된 UV소독을 거친 하수처리장 유출수는 USEPA와 WHO의 가장 엄격한 수질기준을 충분히 만족시켜서 보건 ${\cdot}$ 위생적인 문제를 일으키지 않을 것으로 판단된다. 간헐 분사방식의 완속모래여과 처리후 미생물의 처리효율은 TC, FC, E. coli 모두 평균 95% 이상 높은 처리 효율을 나타내었으며, 완속모래여과 후의 평균 농도는 각각 330, 207, 154 MPN/100 mL이었고 탁도와 SS는 모두 약 50%의 처리효율을 나타내었는데, 이는 WHO의 수질기준을 충분히 만족시켰으며, USEPA의 수질기준인 200FC/100mL의 경우에도 적절한 관리가 이루어 질 경우 만족시킬 수 있을 것으로 판단된다. 탁도는 평균 0.8NTU로써 먹는물 수질기준인 INTU수준이었고, SS의 경우에도 50% 이상의 처리효율을 나타내어 USEPA의 가장 엄격한 수질기준을 충분히 만족하였으며, 영양물질의 제거에도 기여를 하기 때문에 수계의 오염부하를 줄이는 측면에서도 유리할 것으로 생각된다. 연못시스템을 거치면서 TC, FC, E. coli 모두 85%정도 제거되어 평균미생물농도가 1,000MPN/100 m1 이하이었다. 우리나라의 수질기준으로 WHO 수질기준이 논농사에 적용될 경우 소독이나 여과처리 없이도 재이용할 수 있을 것이라 판단되나, USEPA의 수질기준이 적용될 경우에는 연못시스템만으로도 부족하여 추가적인 처리가 필요할 것으로 생각된다. 과거 US EPA의 위험을 완전히 배제한 수질기준을 여러 국가에서 받아들여 사용하고 있으나, WHO에서는 이수질기준이 경제 ${\cdot}$ 사회적으로 불합리한 기준이라 판단하고 보다 완화된 수질기준을 제시하였다. 우리나라에서도 수질기준을 결정할 때 논농사라는 특수한 실정에 맞는 수질 기준을 정해 경제적이고 실용적인 처리방법을 선정하는 것이 중요하다고 할 수 있다. 벼의 경우는 껍질과 추가적인 처리 후 섭취하는 작물이기 때문에 엄격한 수질기준이 필요하지 않을 수 있으나, 장기간 담수상태를 유지함으로써 농민을 포함한 공중보건에 위해성을 줄 가능성이 크므로 세균성미생물 등에 대한 신중한 결정이 필요하다.

• 대한환경공학회지
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• 제32권12호
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• pp.1134-1140
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• 2010

미량오염물질의 산화 및 대체 소독제로 각광받는 오존처리의 하수 2차 처리수중에 잔류하는 의약품류에 대한 제거 성능을 검토하였다. 또한, 의약품류의 제거를 목적으로 한 오존처리에 의한 미생물의 불활성화에 대하여 고찰하였다. 본 연구에서는 시험수로써 하수 2차 처리수를 이용하였으며, 오존처리는 2 mg/L, 4 mg/L, 6 mg/L의 오존 주입량으로 행하였다. 오존처리에 의해 시험수중에서 검출된 37종의 의약품류를 효과적으로 제거하기 위해서는 6 mg/L의 오존 주입량 (오존 소비량 : 4.4 mg/L)이 요구되었다. 동일한 오존처리 조건하에서는 대장균군 및 enteroviruses에 대해 약 3 log의 불활성화가 달성가능할 것으로 고찰되어, 잔류 의약품류의 제거 뿐만 아니라 병원성 미생물에 대해서도 효과적인 소독효과를 달성할 수 있을 것으로 판단되었다. 반면, 6 mg/L의 오존 주입량을 이용한 오존처리시, 처리수중의 용존오존농도가 약 1.8 mg/L까지 증가하여, 발암성 물질인 브로메이트의 생성가능성이 높아질 것으로 예상되었다. 이러한 브로메이트의 생성을 억제하기 위해서는 오존처리와 UV 또는 $H_2O_2$와의 조합공정인 고도산화처리공정에 대한 검토가 필요할 것으로 판단되었다.