• 한국물환경학회지
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• 제16권4호
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• pp.523-532
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• 2000

The purpose of this study was to investigate the effects of the hydraulic retention time (HRT) and organic loading rate (OLR) on microbial characteristics and treatment efficiency in sewage treatment using aerated submerged biological filter (ASBF) reactor. This reactor combines biodegradation of organic substrates by fixed biomass with a physical separation of biomass by filtration in a single reactor. Both simulated wastewater and domestic wastewater were used as feed solutions. The experimental conditions were a temperature of 17 to $27^{\circ}C$, a hydraulic retention time of 1 to 9hr, an organic loading rate of 0.47 to $3.84kg\;BOD/m^3{\cdot}day$ in ASBF reactor. This equipment could obtain a stable effluent quality in spite of high variation of influent loading rate. Total biomass concentration. biofilm thickness and biofilm mass increased an exponential function according to the increasing OLR. The relationships between water content and biofilm density were in inverse proportion. The percentage of backwash water to influent flow was almost 9%. The separation efficiency of biomass was the percentage of 91 to 92 in ASBF reactor. The sludge production rates in feed solutions of simulated wastewater and domestic wastewater were 0.14~0.26 kg VSS/kg BODrem, 0.43~0.48 kg VSS/kg BODrem, respectively.

• 한국환경농학회지
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• 제18권4호
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• pp.310-315
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• 1999

본 연구에서는 생물막법의 일종인 흡수성 Biofilter 시스템(ABS)을 설치하여 14개월의 실험기간 동안 건국대 농생대 구내의 염기성 부패조로부터 유입수를 3가지 수리부하율로 처리하여 시험하였다. 모니터링 결과에 의하면 ABS는 평균농도 $BOD_5=6.2mg/l$, TSS=4.4mg/l 이라는 아주 낮은 유기성 유출수를 연속적으로 발생시킬 수 있음이 확인되었다. 이러한 저농도 유출수는 현재 우리나라 오분법의 특정지구(상수원 보호구역)에 대한 방류수 기준($BOD_5=10mg/l$, TSS=10mg/l)에도 훨씬 못 미치는 양호한 농도로서 ABS의 우수한 유기성오수 처리성능이 입증되었다. 특히 유출수내의 TSS 농도가 지극히 낮아서 슬러지의 발생이 거의 없으므로 침전조를 생략할 수 있어 설치비용이 저렴해지고, 유지관리가 단순한 장점을 지니고 있음을 알 수 있었다. 그러나 ABS시설이 농촌에 널리 보급되어 실용적인 시스템이 되기 위해서는 앞으로 T - N과 T- P의 처리효율 향상 방안, 겨울철에 대한 Biofilter탱크내 임계온도 유지문제, 광역모니터링 및 신속보수 유지관리체계 확립에 대한 계속적인 연구가 필요하다. 이러한 문제점만 어느정도 해결된다면 ABS는 우리나라 농촌의 소규모 현장 오수처리시설로서 앞으로 미래가 밝은 차세대형 시스템이 될 것으로 확신한다.

• 한국농공학회지
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• 제42권4호
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• pp.96-105
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the performance of constructed wetland system for wastewater treatment in rural area. The constructed wetland system was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the treatment basin. The treatment basin was composed of sand bed with planted reed. From August 1996 to June 1998 the hydraulic loading rate was fixed with about 15.63cm/day and theoretical detention time was 1.38 days, and from July 1998 to December 1999 the hydraulic loading rate was about 6.25cm/day and theoretical detention time was 3.5days. It worked continuously even during winter time, and the sewage flowed without freezing even when average daily air temperature was below -1$0^{\circ}C$. Average removal rate of BOD , COD, and SS was about 70%, T-P removal rate was about 50.8% , and T-N removal rate was 23.9%. The reason for poor T-N removal might be due to high influent concentration and short retention times. At the later years BOD and COD removal rates were increased , and SS and T-P removal rates did not change significantly , but T-N removal rates were decreased. The effluent of the wetland system often effluent water quality standards for sewage treatment plant, therefore, further treatment would be required if the effluent need to be discharged to the public water. Wetland system involves relatively large land area and could be suitable for rural area. Therefore, utilization of reclaimed sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage in rural area.

• 상하수도학회지
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• 제7권1호
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• pp.46-53
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• 1993

This study was carried out to examine substrate removal characteristics with the variation of the hydraulic retention time in an anaerobic filter. The feed concentration of synthetic wastewater used in the experiment was $10,000mg/l$ glucose. As media, the porosity of volcanic stones in Jeju island were 76%. The conditions of the experiment were as follows; HRT ranging from 1 day to 3 day, loading rates ranging from 3.33kg $COD_{er}/void\;m^3.day$ to 10kg $COD_{er}/void\;m^3.day$ and a temperature $35^{\circ}C$. Based on the results of the experiments, the COD removal efficiency was 98~99% in $COD_{er}$ method with loading rates ranging from 3.33kgCOD/void $m^3.day$ to 10kg COD/void $m^3.day$ and HRT ranging from 1day to 3 day. The produced quantity of gas equivalant to a porosity volume was $1.332~3.756Nm^3/void\;m^3.day$. The relationship between $COD_{er}$ loading rates and gas produced quantity equivalant to a porosity volume was well fitted with the equation of $Nm^3/void\;m^3.day{\cdot}=0.359L_0+0.179$($L_0=COD$ loading rate). Judging from the removal efficiency in this experiment, We concluded that anaerobic filter using Volcanic stones is one of improved and effective. As media, practical value of volcanic stones is sufficient.

• Environmental Engineering Research
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• 제12권2호
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• pp.81-91
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• 2007

A membrane bioreactor (MBR) was used to investigate the aerobic degradation of foam active substance - non-ionic surfactant, APG 2000 UP. The surface aeration using the propeller loop reactor (PLR) guaranteed sufficient $O_2$ for substrate removal and bacteria growth and avoided foam development. Moreover, the cross-flow membrane filtration enabled the separation of the bacteria still loaded with surfactant in the collecting container. The biological degradation of the surfactant with varying hydraulic retention time (HRT) and influent concentration $c_{S0}$ showed high substrate removal of nearly 95% at high volumetric loading rates up to $7.4\;kgCOD\;m^{-3}d^{-1}$ and at sludge loading rates up to 1.8 kgCOD $(kgVSS\;d)^{-1}$ for biomass concentration $c_B\;{\approx}\;constant $. The increasing $c_B$ from 3.4 to $14.5\;gL^{-1}$ TSS respectively sludge retention time (SRT) from 5.1 to 442 d under complete biomass retention by the membrane filtration resulted in high removal of substrate ${\alpha}\;>\;90%$ with reducing excess sludge production.

• 산업기술연구
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• 제22권B호
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• pp.109-115
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• 2002

This research was performed to investigate the COD removal efficiency and methane production in slurry-typed swine wastes using UASB(upflow anaerobic sludge blanket)reactor. The USAB reactor was operated from 0.8 through 3.3days of HRT in a range of 3 to 15 kg $TCOD/m^3/day$ of volumetric organic loading rate. The removal rate of TCOD was increased with the increase of the HRT. The removal rate of TCOD at an HRT over 2days, became greater than 68% with the methane contents being from 70 to 80%. Methane production rates were increased from 0.27 to $0.36m^3\;CH_4/kg$ CODrem. as HRTs were increased from 0.8 to 3.3days.

• 상하수도학회지
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• 제31권5호
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• pp.415-419
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• 2017

In recent years there have been large increases in the hydraulic loading rates used to design dissolved air flotation (DAF) facilities for drinking water applications. High rate DAF processes are now available at loading rates of 20 to $40m^3/m^2{\cdot}h$. This research evaluated dissolved air flotation as a separation method for algae and organic compounds from water treatment plants. During the service period of 2016. 5. to 2017. 6., DAF pilot plants ($500m^3/day$) process has shown a constantly sound performance for the treatment of raw water, yielding a significantly low level of turbidity (DAF treated water, 0.21~1.56 NTU). As a result of analyzing the algae cell counts in the influent source, it was expressed at 100-120 cells/mL. In DAF treated water, the removal efficient of alge cell counts was found to be upto 90%. The stable turbidity and algae removal were confirmed by operating the high rate DAF process under the condition of the surface loading rate of $30m^3/m^2{\cdot}hr$.

• 한국양식학회지
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• 제16권4호
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• pp.203-209
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• 2003

Nitrification efficiency of fixed film biofilters with sand, loess bead, and styrofoam bead in biofilter columns of 1-m height and 30 cm width was studied. Synthetic wastewater was continuously supplied to the culture tank to maintain total ammonia nitrogen (TAN) concentration in the inflow water at around 8 mg/L. The hydraulic loading rate was set at 200 ㎥/$m^2$/day. TAN conversion was stabilized after about 90 day conditioning for all the selected filter media but with net accumulations of nitrite. On the volumetric basis, conversion rates of TAN and nitrite were the highest in styrofoam bead filter. Mean volumetric TAN conversion rates in the final samples were 682, 269, and 79 g TAN/㎥/day in the styrofoam bead, sand and loess bead filters, respectively. Low gravity and cost of styrofoam bead render the handling easier and more cost-effective.

• 한국수산과학회지
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• 제29권2호
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• pp.230-237
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• 1996

본 연구는 살수여상공법을 양어장 순환수 처리 장치로 설치하여 유기물질 제거 효율, 암모니아 제거효율, 동력학적 상수, 슬러지 생산량과 산소소요량 등의 최적 운전방법을 도출하였다. 유기물질 부하율이 $0.500\~0.082kg\;COD/m^3/day$에서 $66.4\~81.2\%$의 SCOD 제거 효율과 $74.5\~84.0\%$의 SBOD 제거 효율을 보였다. 암모니아 부하율이 $0.271\~0.044kg\;NH_4^+-N/M^3/day$에서 $43.7\~61.8\%$ 의 암모니아성 질소 제거 효율을 보였으며 암모니아 제거량은 $27.2\~119.5mg\;NH_4^+-N/L/day$로 나타났다. Eckenfelder 식에 의해 구한 K, n값은 각각 $0.168\;min^{-1}$과, 0.132로 나타났으며 총 생성된 슬러지 생산량은 0.233g VSS/day로 kg BOD 제거량당 생성되는 슬러지 생산량은 0.572 kg VSS/kg $BOD_{rem}$로 나타났다. 산소소요량은 3.89mg $O_2/L/hr$로 수리학적부하가 $6.712\~40.341\;m^3/m^2/day$에서 $1.33\~7.22\;mg\;O_2/L/hr$로 수리학적 부하가 증가할수록 산소소요량이 증가하였으며 미생물당 산소소모율은 1.08kg $O_2/kg$ VSS로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1670-1679
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• 2015

Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH₄⁺-N/m³/d and 0.10-0.21 kg NO₃^--N/m³/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH₄⁺ or NO₃^- loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs.