• 한국물환경학회지
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• 제28권4호
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• pp.505-511
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• 2012

While the existing sewage treatment facilities are mainly being operated by biological processes, winter-time efficiency improvement and additional phosphorus treatment equipment using chemicals have been required to follow the effluent criteria of TP (0.2, 0.3 and 0.5 mg/L for the zone of I, II and III respectively) and $BOD_5$ (5.0 mg/L) which is intensified from 2012 in Republic of Korea. We made an investigation into actual condition of biological treatment process and calculated the optimal chemical input amount by jar test of supernatant of secondary sedimentation tank to evaluate the process improvement for the intensified criteria. Ejector BAF system for removing TP, $BOD_5$ of sewage effluent was suggested. The concentration of TP from biological process is 0.3-0.8 mg/L, and the input amount of optimal chemical coagulant was above Al/P ratio of 3(1.9 mg/L as Al) to meet the criteria of TP for secondary treatment effluent. From the results of this experiment, the best Al/P ratio for Ejector BAF system was about Al/P ratio of 1, and LV of BAF process for intensified criteria of $BOD_5$ and TP was below 1.97m/hr.

• 미생물학회지
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• 제30권2호
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• pp.113-118
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• 1992

소양호에서 인(P) 의 순환 과정중 유기인산염 분해율을 1990 1월 부터 1991녕 4 월 까지 측정한 결롸 1-2220 nM/l/hr 의 범위였다. 표층의 경우 8월에 가장 높았으며, 성층이 깨지는 10월과 11 월에는 8월보다 1/240배 이하로 낮은 값이였다. 우기인산염 분해율과 엽록소 a 와는 높은 상관 관계(R = 0.69) 를 나타내었고, specific activity는 겨울에 45-122 nM/hr/$\mu$g chl. a 으로조사기간중 최조값을, 10월에는 2 nM/hr/$\mu$g chl. a 로서 최저값을 나타내었다. 유기인산염 분해율과 DIP 농도와는 역상관의 관계이였다. 성층기에는 식물 플랑크톤이 증식하면서 유도된 alkaline phosphatase 에 의하여 유기인산염을 분해하고, 표, 심층부가 섞이는 가을에는 중, 심츤부로부터 충분한 양의 DIP 가 공급되는 것으로 나타나, 소양호의 부영양화 상태가 매우 심각함을 알 수 있었다.

• 대한토목학회논문집
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• 제36권4호
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• pp.651-657
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• 2016

본 연구의 목적은 마이크로버블을 이용하여 외부탄소원으로서 음폐수의 재활용 가능성을 검토해 보고자 하였다. 가압탱크 압력 3 bar, 순환유량 3.65 LPM, 공기주입량 0.3 LPM의 회분식으로 진행된 실험에서 마이크로버블 접촉시간의 경우 18시간이 음폐수 외부탄소원의 재활용 기준을 만족하는 적정 시간임을 확인하였다. 회분식 실험 결과를 바탕으로 체류시간을 12, 14, 16, 18시간으로 설정하여 연속식 실험을 하였다. 연속식 실험에서도 체류시간 18시간에서 T-P를 제외한 SS, T-N, n-Hexane 추출물질, VFA 항목에서 외부탄소원 재활용기준을 만족하였다. 음폐수 원수 중 용존성 인의 농도가 전체 인 농도 중 약 88.5% 이상으로 용존성 인의 제거를 위해서는 응집제 사용이 필요함을 알 수 있었다. 또한, VFA의 경우 호기성 조건에서 유기물의 분해속도 및 농도에 따라 크게 영향을 받기 때문에 외부탄소원 재활용기준을 만족하기 위해서는 적절한 체류시간 선정 또는 산발효조 공정의 추가가 필요할 것으로 사료된다.

• 한국농공학회논문집
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• 제49권5호
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• pp.57-65
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• 2007

The objective of this study was to evaluate chemical water quality by hourly monitoring(25hr) of Saemangeum esturary. For this study, we selected 2 sites like a Mangyong Bridge(St. 6) and Dongjin Bridge(St. 7). Inflow of salt water was not detected during low tide(maximum 553, 508cm) of all stations, while the salinity rises were detected in spring tide(750cm). When 602m of maximum tide was reached, salinity concentration was increased at St. 7, while there was no change in St. 6. Therefore, We know that salinity variation is greatly influenced by tide height at survey site. Also, significant variance of salinity(p<0.05) was found between St. 6 and St. 7 because dike construction made the flood tide move into the Dongjin river. Total suspened solids(TSS) concentration was increased because of the river runoff at St. 6, and also the turbulance and resuspension according to salt intrusion at St. 7. During the high tide, the water discharge from the sea seemed to dilute the nutrient but to elevate TSS concentration in St. 7. Silicate and nitrate concentrations in the studied site were decreased by the mixing of sea water, whereas the evident trend of phosphate concentration was not found. This result can be explained by the phosphorus condition. Phosphorus exists inactive when it is affected by hydrated iron and adsorbed onto suspended matters. Compared to the environmental conditions of the St. 6 and St. 7, physical factors such as temperature, dissolved oxygen and TSS have statistically no significant difference(p<0.001), but nutrient concentrations were higher at St. 6 than St. 7. It could be suggested from these results that it is important to control the discharge of fresh water by sewage treatment plants located in St. 6 for water quality management.

• 한국양식학회지
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• 제6권3호
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• pp.187-197
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• 1993

미국 알라바마주의 중서부 지역에 밀집되어 있는 차낼메기 양어장의 수질을 조사하여 양어장 물이 배출되는 그 주변 하천의 수질과 비교하였다. 양어장의 사육 밀도는 헥타르당 10,000마리였으며, 밤 동안(0000-0600)에는 산소를 공급하기 위하여 수차를 사용하였고, 먹이 공급은 일주일에 6일 동안 하였다. 메기 양어장에서 방류되는 사육수의 오염 정도를 알아보기 위하여 양어장의 표층 30cm와 저층에서 1990년과 1991년에, 계절별로 시료를 채취하여 수질 변수를 측정하였다. 수온, 용존산소, pH, 침전성물질, 총부유물질, 휘발성물질, 총인, 용존인, BOD, 총암모니아, 아질산염, 질산염, 그리고 총켈달질소의 평균값은 표층과 저층의 시료사이에 차이가 없었다 (P>0.05). 양어장의 수질은 주변 하천수에 비해서 오염도가 높았으며, 특히 질소와 인의 농도는 아주 높았다.

• 생태와환경
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• 제37권4호통권109호
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• pp.406-410
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• 2004

2000년 두 댐 저수지와 유입 하천에서 월별 alkaline phosphatase activity (APA)을 측정하였다. 또한 2001년 여름 동안은 한 댐 저수지에서 APA의 수직변화와 관련된 요인들을 조사하였다. APA는 여름 동안 저수지 표층에서 상대적으로 높게 나타났으나 심층에서는 거의 변화가 없었다. 그러나 바닥층 바로 윗부분에서는 APA의 미미한 증가 관찰되었다. APA변화와 용존무기인 농도 변화와는 상관관계가 없었으며, 이 결과 조사 대상 저수지에서 APA는 인 이용성의 상태를 의미하지는 않는 것으로 추정되었다. 시료의 size-fractionation 분석 결과, 조사 대상 저수지들에서 APA는 $0.4{\mu}m$보다 큰 입자들에 흡착된 반면, 유입 하천에서는 용존형태로 존재하는 것으로 판단되었다. 저수지 유광층에서 엽록소-a의 농도와 APA간에 유의한 양의 상관성이 나타났다. 무광층에서 APA는 세균의 colony count와 양의 상관성을 나타냈으나 총 세균수와는 상관성이 없었다.

• 한국물환경학회지
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• 제24권6호
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• pp.741-749
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• 2008

Many small-scale ponds that serve as ecological habitat, recreation and irrigation are faced to eutrophication problem, which causes aesthetic nuisance and ultimately loss of their functions. Thus accurate evaluation of the trophic state of these ponds is essential to provide rational information to the stakeholders so that they can develop effective management actions. In this study, the trophic state of a small pond (Wonheung) that experiencing water quality degradation due to vicinity land development was assessed using various Trophic State Indexes (TSIs) and statistical analysis including Principal Components Analysis (PCA) based on the field monitoring data obtained from May to December, 2007. The results showed that the pond is under eutrophic state with average total nitrogen (T-N) and total phosphorus (T-P) concentrations of $708.1{\mu}g/L$ and $59.3{\mu}g/L$, respectively. The factor loading plot obtained from PCA showed distinct two influencing factors, PC 1 and PC 2. PC 1 was grouped by T-P, Chlorophyll a (Chl-a), suspended solids (SS), TN/TP ratio, and transparency that all strongly related to the eutrophication state, while PC 2 by temperature, conductivity, dissolved oxygen (DO) and turbidity that explains the seasonal water quality variations. The limiting factor was identified as light rather than phosphorus by both T-N/T-P ratio and TSI indexes analysis. The results and methodology adopted in this study can be used for water quality assessment for other small ponds and lakes.

• 한국해양환경ㆍ에너지학회지
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• 제4권3호
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• pp.3-15
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• 2001

목포항의 수질과 영양상태의 계절 변화를 구명하고 평가하기 위하여 1996년 8원부터 1999년 8월까지 3년간 현장 관측과 수질 분석을 실시하였다. 첫째, 투명도, 용존무기질소, 인산인 및 클로로필 a와 같은 수질 항목에 대하여 OECD 영양분류기준을 적용한 결과, 목포항 해수의 영양수준은 4계절 내내 중영양 내지 부영양 상태로 평가되었고, 특히 하계에는 부영양 상태로 나타났다. 둘째, 비록 목포항 수질은 화학적 산소요구량에 의하면 해역수질 환경기준의 2급수 내지 3급수로 평가되지만, 부영양화에 의한 오염지수를 산정한 결과에 의하면, 목포항은 수질이 악화되어 4계절 내내 3급수에도 미치지 못하는 것으로 나타났다. 셋째, 부영양도를 산정한 결과, 특히 하계 또는 추계에 목포항에서 적조 발생 잠재력이 높은 것으로 나타났다. 넷째, 해수중에 존재하는 인에 대한 질소의 평균원자비(N/P)를 살펴보면, 목포항에서 식물플랑크톤의 성장에 대한 제한 영양 인자는 질소라기보다는 인으로 나타났다

• 한국물환경학회지
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• 제34권3호
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• pp.301-307
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• 2018

This study investigated the effects of sediment removal on water quality and phytoplankton development by setting up mesocosms at Uiam Lake, South Korea, and analyzing the environmental parameters and phytoplankton communities between June and October 2015. The comparison between testbed without sediment removal (TB-1) and testbed after sediment removal (TB-2) gave similar values for water temperature, pH, dissolved oxygen (DO), and electrical conductivity. Nevertheless, the average electrical conductivities of the two testbeds were $139{\mu}S/cm$ and $135{\mu}S/cm$, which were lower than the value obtained from the external control point (TB-con; $154{\mu}S/cm$). The small difference in total phosphorus (TP) and total nitrogen (TN) concentrations between the two testbeds implied that sediment removal did not greatly reduce nutrients; however, the phytoplankton cell count had decreased by approximately 37 % in TB-2 (average 1,663 cells/mL) compared to TB-1 (average 2,625 cells/mL). Compared to TB-con, the phosphorus and nitrogen concentrations of the two testbeds had decreased by 39 % and 30 %, respectively, whereas the phytoplankton abundance had decreased by up to 73 %, perhaps because of the blocked inflow of nutrients and the stabilized body of water caused by the installation of the mesocosm. The concentration of geosmin was lower in testbeds than in the external point, because installation of the structures had reduced the cyanobacteria biomass.

• 한국환경과학회지
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• 제20권12호
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• pp.1521-1531
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• 2011

This study was carried out to determine the characteristics of the marine environment, including nutritional content, in order to clearly understand the outbreaks of Gonyaulax polygramma in the southern coastal areas in August, 2009. Samples were collected at 13 sites and water temperature and salinity were measured using a CTD. Field surveys were twice: the first between August 5-7, the second between August 22-24. The cell density of G. polygramma was 6,500-10,000 cells $ml^{-1}$ during the $1^{st}$ survey, whereas during the $2^{nd}$ survey the range of the cells was recorded from 8,000 to 12,500 cells $ml^{-1}$. Cochlodinium polykrikoides ranged from 0 to 105 cells $l^{-1}$ during the field survey. In water environments, the majority stations during the $1^{st}$ survey showed a nearly homogeneous water column below $1^{\circ}C$ in temperature, as well as similar profiles of salinity. However, the stratification between the surface and bottom was observed in the $2^{nd}$ survey. Regarding nutrients, Dissolved Inorganic Nitrogen (DIN) in the surface ranged from 0.144 to 0.236 mg $l^{-1}$ during the $1^{st}$ survey, and 0.082-0.228 mg $l^{-1}$ during the $2^{nd}$ survey. DIP (Dissolved Inorganic Phosphorus) did not show any difference in concentration between the $1^{st}$ and $2^{nd}$ survey. During August of 2009, the wind speed in the southern waters remained at around ${\leq}2\;m\;s^{-1}$ for about 60% of time, and there was very little precipitation during the month. Irradiance of ${\geq}10$ hr was shown in the late of August. It is thought that a low level of DIN and salinity play an important role as an essential factor for rapid growth, wide distribution and longer duration of red tide in G. polygramma.