• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.46-52
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• 2007

As flue gas desulfurization (FGD) wastewater contains high concentrations of nitrate and is very low in organic carbon, the feasibility of nitrate removal by autotrophic denitrification using Thiobacillus denitrificans was studied. This autotrophic bacteria oxidizes elemental sulfur to sulfate while reducing nitrate to elemental nitrogen gas, thereby eliminating the need for addition of organic compounds such as methanol. Owing to the unusually high concentrations of dissolved salts $(Ca^{2+},\;Mg^{2+},\;Na^+,\;K^+,\;B^+,\;SO_4^{2-},\;Cl^-,\;F^-,)$ in the FGD wastewater, extensive laboratory-scale and pilot-scale tests were carried out in sulfur-limestone reactors (1) to determine the effect of salinity on autotrophic denitrification, (2) to evaluate the use of limestone for pH control and as source of inorganic carbon for microbial growth, and, (3) to find the optimum environmental and operational conditions for autotrophic denitrification of FGD wastewater. The experimental results demonstrated that (1) autotrophic denitrification is not inhibited up to 1.8 mol total dissolved salt content; (2) inorganic carbon and inorganic phosphorus must be present in sufficiently high concentrations; (3) limestone can supply effective buffering capacity and inorganic carbon; (4) the high calcium concentration may interfere with pH control, phosphorus solubility and limestone dissolution, hence requiring pretreatment of the FGD wastewater; and, 5) under optimum conditions, complete autotrophic denitrification of FGD wastewater was obtained in a sulfur-limestone packed bed reactor with a sulfur:limestone volume ratio of 2:1 for volumetric loading rates up to 400g $NO_{3^-}N/m^3.d$. The interesting interactions between autotrophic denitrification, pH, alkalinity, and the unusually high calcium and boron content of the FGD wastewater are highlighted. The engineering significance of the results is discussed.

• 상하수도학회지
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• 제22권6호
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• pp.673-679
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• 2008

The representative microorganism of autotrophic denitrification using sulfur granule, oxidizes the reduction from S and performs denitrification by reducing $NO_3{^-}-N$ to $N_2$ gas. The sampling of autotrophic denitrification microorganisms has been performed from foreshore sludge, condensed sludge, and active sludge, but the analysis of autotrophic denitrification microbial community characteristics has been lacking. Based on the separation and identification of each sample using the PCR and DGGE methodologies, many types of sulfuric microorganisms and autotrophic denitrification microorganisms were found.

• 한국농공학회논문집
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• 제49권2호
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• pp.75-86
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• 2007

This process which has a connection of biofilter and sulfur-limestone has been developed to treat organic substances including BOD, COD and SS etc. and to treat sulfur-limestone is for denitrification.. The whole process consists of chemical reaction tank, sedimentation tank, trickling filter, denitrification tank The trickling filter is equipped with a reactor filled with absorptive filter, and the sulfur denitrification tank is filled with sulfur-limestone mixed media. After setting up practical facilities whose capacity is 60 tons a day, we have observed the removal efficiencies of pollutants through 60 experiments during Summer and Winter seasons. The average concentration of polluted water was BOD for 3.6 mg/L, $COD_{Mn}$ for 11.3 mg/L, SS for 2.8 mg/L, T-N for 8.6 mg/L, and T-P for 0.8 mg/L, and the rate of treatment efficiencies 96.5%, 84.7%, 96.5%, 79.2%, and 80.8%, respectively was found through the experiments. The average treatment efficiency for BOD and $COD_{Mn}$ was 85.0% and 55.7%, respectively and the average removal efficiency for NH4+-N was 84.9% in the trickling filter. The removal efficiency in the denitrification tank is as follows; The removal rate of $NO_3^--N$ was as high as 93.2% within the compass of pH 6.3 to 7.3 through $16.8{\sim}37.0mg/L$ flown into $NO_3^--N$ and $0.1{\sim}8.3mg/L$ outflown. It had observed that this process has implemented highly efficient and advanced treatment without external carbon sources and internal recycle during its process. In conclusion, this process is suitable for a sewerage in a small village due to the merits of low power consumption and easy maintenance.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.455-460
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• 2005

A pilot-scale sulfur particle autotrophic denitrification (SPAD) process for the treatment of municipal wastewater was operated for 10 months at Shihwa, Korea, and higher than $90\%\;NO^{-}_{3}-N$ removal efficiency was observed. Plate counting showed that the lower part of the denitrifying column reactor had the most autotrophic denitrifiers. The biofilm thickness formed on sulfur particles from the SPAD reactor was approximately $25-30\;{\mu}m$, measured by DAPI (4,6-diamidino-2-phenylindole) staining. The presence of bacteria inside the highly porous sulfur particle was also monitored by SEM observation of the internal surfaces of broken sulfur particles. Biofilm extracellular polymeric substances (EPS) analysis showed that the ratio of carbohydrate to protein decreased with the reactor heights at which biofilm-formed sulfur particles were obtained.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.68-71
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• 2002

SPAD공법은 탈질을 위한 전자공여체로 입자상의 황과 소량의 메탄올을 이용하는 생물학적 공법이다. 이번 연구에서 SPAD공법은 특정 폐수에의 적용가능성을 평가하기 위해 고농도의 칼슘이온을 함유한 울산의 S특수강 폐수(200-300$NO_3\;^-$ -N/L)에 적용되었다. 운전기간은 2001년 11월부터 2002년 3월 초까지였으며 반응조 내부의 온도는 약 $20^{\circ}C$ 부근으로 유지되었고, 그러한 낮은 온도조건하에서도 탈질 효율은 90%이상으로 유지되었으며 유출수 농도는 약 20mg $NO_3\;^-$ -N/L정도로 유지되었다. 따라서 SPAD공법은 고농도의 칼슘이온을 함유한 폐수에 대해 적용이 가능한 것으로 사료되어진다.

• 대한환경공학회지
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• 제22권10호
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• pp.1777-1787
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• 2000

본 연구에서는 황-이용 독립영양 탈질을 위한 경제적이면서도 효율적인 알칼리원의 선정을 위하여 숯, 연탄재, 패각 및 석회석을 대상으로 희분식 실험 및 연속실험을 실시하여 $NO_3{^-}-N$ 부하에 따른 탈질효율을 파악하였다. 희분식 실험 결과 패각 및 석회석이 가장 우수한 산 중화능력을 보였으나, 넓은 표면적을 가진 패각이 석회석보다 알칼리도 공급능력이 더 좋은 것으로 나타났으며, 황과 패각간의 혼합비는 1/1 (V/V)이 가장 효율적인 것으로 판단되었다. $NO_3{^-}-N$의 농도를 증가시키면서 수행한 연속실험 결과, 116 g $NO_3{^-}-N/m^3-day$의 부하까지는 90% 이상의 탈질효율을 나타내었으나, 145 g $NO_3{^-}-N/m^3-day$의 부하에서는 탈질효옳이 48%로 악화 되었다. 제거된 $NO_3{^-}-N$ 1 g당 생성된 $SO_4{^{2-}}$의 양은 평균 7.02 g으로 이론값인 7.54 g보다 낮게 나타났다. $NO_3{^-}-N$의 탈질은 반응속도상수가 평균 0.146/hr인 1차 반응으로, 그리고 $SO_4{^{2-}}$의 생성은 반응속도상수가 평균 -53.1 mg/L-hr인 0차 반응으로 나타났다. $NO_3{^-}-N$의 탈질량에 비례하여 가스가 발생되었는데, 질소 물질수지를 따진 결파 제거된 질소중 71~109%, 평균 90%가 $N_2$가스로 회수되었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.209-212
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• 2000

As a bench-scale study, transformation of nitrate to nitrogen gas under anoxic condition was determined by using autotrophic denitrifiers containing Thiobacillus denitrificans and elemental sulfur as an electron donor. The research objective is to measure the basic kinetic parameters of autotrophic denitrification reaction on the removal efficiency of nitrate. The results showed that nitrate was almost completely transformed to nitrite in the first 4 days of column operation. After 2 days of accumulation of nitrite, its concentration slowly decreased and the compound was detected less than 0.5 mg/L in 14 days. In the experiment, sulfate concentration in the effluent was the 70~90 mg-S/L and the pH was maintained around pH 7.5. When nitrate concentration of bank filtrate in the real field is considered, this sulfate concentration seems to be acceptable. At 17 cm from the bottom of the column, the effluent showed the highest nitrite concentration, and nitrate concentration decreased rapidly to the Point of 33 cm from the bottom. The results suggest that an appropriate thickness of permeable reactive barriers is about 30 cm.

• 한국환경농학회지
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• 제29권3호
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• pp.221-226
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• 2010

축산폐수는 고농도의 유기물 및 질소를 함유하고 있으므로 적절한 처리 방법이 요구된다. 본 연구는 황을 이용한 독립영양 탈질 방법으로 질산성 질소에서 질소가스로의 탈질이 아닌 아질산성질소에서의 황산화 탈질을 연구하였으며 탈질 미생물의 최적 성장 조건을 찾고자 하였다. 초기 알칼리도가 충분한 조건에서는 아질산성질소 탈질 저해가 관찰되지 않았으며 실험온도가 $20^{\circ}C$인 경우에도 $30^{\circ}C$와 비교할 때 큰 저해 없이 탈질이 진행되었다. 하지만 초기 아질산성질소의 농도 300 mg/L 이상에서 lag phase가 늘어나 기질저해가 나타났다. 알칼리도가 충분하지 않은 조건에서 질산성질소의 탈질효율은 10%인 반면 아질산성질소의 탈질의 95% 이상이었다. 산소가 존재할 경우 산소를 이용하여 탈질이 이루어지지 않았음에도 불구하고 황산화 미생물이 산소를 이용하여 황산염의 농도가 증가하였다. 아질산성질소 탈질 시 알칼리도의 소모가 관찰되었으나 질산염 탈질시 보다 알칼리도의 소모가 적었으며 황산염 생성 또한 적었다. 황이용 아질산성 질소 탈질은 외부탄소원의 추가적인 주입 없이 저렴한 황입자를 이용하며 질산성질소 황산화 탈질의 단점인 알칼리도 파괴, 황산염이온 생성의 단점을 보완할 수 있는 효과적인 탈질 방법이 될 것으로 기대된다.

• 상하수도학회지
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• 제20권4호
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• pp.519-526
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• 2006

In this study, the major operating factors in SND(simultaneous nitrification and denitrification) using bioreactor packed with submerged cilia media and granular sulfur such as variation of nitrification rate, organic matter removal efficiency and denitrification efficiency in different DO concentration were mainly evaluated. Synthetic wastewater and actual sewage were used as influent wastewater. Experiment with synthetic wastewater as influent wastewater was divided into three phases with the adjustment of DO concentration. As the results, nitrification efficiency and T-N removal efficiency in the Phase 3(DO 1.0~2.0 mg/L) were 99% and 52.3%, which is significantly greater than those in other two phases. Also, loading rate and denitrification efficiency of SCPGS(Submerged Cilia media Packed with Granular Sulfur) were calculated as $0.44kg\;NO_3^--N/m^3-day$ and 50%, respectively. On the other hand, nitrification rate was decreased from 99% to 64% according to the DO concentration with the variation from 3.0~3.5 mg/L(phase1) to 0.4~0.6mg/L(phase2). Although the nitrification rate was decreased in 64% according to the variation of the DO concentration, T-N removal rate was rapidly increased to 49% by increasing of the denitrification efficiency. Experiment with actual sewage as influent wastewater was carried out to evaluate efficiency of SCPGS in real operation condition of full-scale sewage water treatment plant. At the time, T-N removal rate in this experiment and full-scale wastewater treatment plants were given by 43% and 20%, respectively. The above results indicate that SCPGS can be used as an advanced treatment process for economical efficiency considered.

• 대한환경공학회지
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• 제32권9호
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• pp.851-856
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• 2010

본 연구는 단축질소제거(SBNR) 공정의 후속 공정 목적으로 황이용 독립영양탈질을 이용하여 유출수 내 아질산성질소를 제거하고자 황 이용 아질산성질소의 제거특성을 파악하였다. 이를 위하여 알칼리도가 이론적인 양보다 충분한 조건과 부족한 조건에서 아질산성질소와 질산성질소의 황탈질 회분식 실험을 수행하면서 메탄올의 영향을 파악하였다. 충분한 알칼리도와 완전독립영양 조건에서 초기 아질산성질소, 질산성질소 농도가 각각 100 mg N/L에서 배양 27시간 이내에 99% 이상의 질소가 제거 되었다. 탈질 속도는 질산성질소 탈질에 비해 아질산성질소 탈질이 약 1.3배 빨랐다. 아질산성질소 탈질 시 1 g 당 황산염 이온 생성량은 약 4.8 g ${SO_4}^{2-}/g$ ${NO_2}^-$-N 이었고, 질산성질소 탈질의 경우 13.5 g ${SO_4}^{2-}/g$ ${NO_3}^-$-N이었다. 알칼리도가 충분하지 않은 조건에서 아질산성질소는 95% 이상 높은 효율을 보였으나 15시간 정도의 긴 유도기가 관찰되었고, 질산성질소 탈질의 경우 배양기간 동안 전혀 탈질이 이루어지지 않았다. 아질산성질소 탈질에서 제거된 아질산성질소 1 g 당 황산염 이온 생성량은 약 2.6 g이었고 알칼리도 소비량은 1.2 g $CaCO_3$이었다. 모든 알칼리도 조건에서 투여한 메탄올의 아질산성질소 제거 영향은 없었다. 본 연구결과를 바탕으로 황이용탈질의 특성을 파악하여 하수 및 폐수의 특성에 맞게 반응조 운전이 이루어지면 기존 탈질 방법의 단점을 보완한 효율적인 탈질 방법이 될 것으로 판단된다.