남해안 주요 하구 갯벌 퇴적물의 탈질소화를 통한 질소 영양염 제거

허낙원,이지영,최재웅,안순모,Heo, Nak-Won,Lee, Ji-Young,Choi, Jae-Ung,An, Soon-Mo 한국해양학회 2011 바다 Vol.16 No.2

남해안의 주요 하구 4곳(순천만, 섬진강, 고성천, 마산만)과 서해안의 태안 근소만 갯벌에서 2009년 3월부터 2010년 5월까지 유기물 정화능력을 파악할 수 있는 퇴적물 산소요구량(Sediment Oxygen Demand; SOD)과 탈질소화(Denitrification)를 측정하였다. 퇴적물 산소요구량은 퇴적물 배양 중 시간당 용존산소감소율로 부터 추정되었으며, 탈질소화 측정에는 질소 안정동위원소를 추적자로 이용하는 isotope paring technique이 사용되었다. 조사지역의 퇴적물 산소요구량과 탈질소화율은 각각 -5.1~24.6 mmole $O_2m^{-2}d^{-1}$와 0.0~3.9 mmole $N_2m^{-2}d^{-1}$의 범위를 보였다. 퇴적물 산소요구량이 가장 높은 곳은 마산만(평균 = 10.2(범위 =-2.2~19.2 mmole $O_2m^{-2}d^{-1}$)이었으며, 순천만, 고성, 태안, 섬진강 순으로 나타났다. 탈질소화율도 마산만(평균 = 1.0(범위 =0.0~3.9) mmole $N_2 m^{-2}d^{-1}$이 가장 높았으며, 고성, 섬진강, 순천만, 태안 순으로 나타났다. 태안, 섬진강, 마산 지역에서는 계절적으로 저서미세조류에 의한 광합성이 탈질소화에 뚜렷한 영향을 미쳤는데 광합성 동안 생성된 산소는 혐기성과정인 탈질소화를 저해하기 보다는 질산화를 원활하게 하여, 질산화-탈질소화 연계과정을 촉진시켰다. 남해안 허구에서 탈질소화의 계절변화 유형(봄철 최대 유형과 여름철 최대 유형)의 지역적 차이는 탈질소화에 사용되는 두 질산원($D_w$; 강을 통해 공급된 질산과 $D_n$; 질산화-탈질소화 연계과정에 의해 생성된 질산)의 상대적 중요성에 따라 결정되었다. 즉 봄철에 탈질소화가 높게 나타난 순천만, 고성, 마산은 여름철에 비해 봄철 수층 질산염이 풍부하였고, 이를 통해 $D_w$가 증가되었다. 태안과 섬진강 지역이 여름철에 탈질소화 최대값을 보인 이유는 수층의 질산염이 고갈되지 않은 상태에서 여름철 수온의 증가로 $D_w$가 증가하였고, 이와 더불어, 산소고갈이 나타나지 않아 질산화에 좋은 환경이 조성되었으며, 결과적으로 $D_n$이 증가되었기 때문이다. Sediment oxygen demand(SOD) and denitrification rates were measured in four major estuaries(Suncheon Bay, Seomjin river estuary, Goseong stream estuary and Masan Bay) in south coast of Korean peninsula from March of 2009 to May 2010 to estimate organic matter cleaning capacity. SOD was estimated from the temporal dissolved oxygen concentration change and isotopic pairing technique was employed to measure denitrification. Sediment oxygen demand(SOD) was ranged from -5.1 to 24.6 mmole $O_2m^{-2}d^{-1}$ and denitrification rate was ranged from 0.0 to 3.9 mmole $N_2m^{-2}d^{-1}$in the study area. SOD was the highest in Masan Bay(-2.2 to 19.2, average = 10.2 mmole $O_2m^{-2}d^{-1}$) and Suncheon, Goseong, Tae-an and Seomjin followed. Denitrification was also the highest in Masn Bay(0.0 to 3.9, average = 1.0 mmole $N_2m^{-2}d^{-1}$) and Goseong, Seomjin, Suncheon and Taean followed. The effect of benthic photosynthesis by microphytobenthos on denitrification was evident in some season of Tae-an, Seomjin, and Masn Bay. The increased oxygen level produced by photosynthesis stimulated nitrification without severe adverse effect on denitrification and, as a result, coupled nitrification and denitrification was enhanced in these areas. A difference of seasonal patterns of denitrification at each site depended on relative importance of denitrification on different nitrate source($D_w$: nitrate from water column and $D_n$: nitrated produced during nitrification). Denitrification was maximum during spring in Goseong, Suncheon and Masan Bay. On the contrary, denitrification was the highest during summer in Tae-an and Seomjin estuary.

H₂O₂/O₃ AOP와 UASB 공정을 이용한 매립지 침출수 처리(I) - H₂O₂/O₃ AOP 전처리 및 질소원에 따른 침출수별 처리특성 -

정승현,정병곤,Jeong, Seung Hyun,Jeong, Byung Gon 한국물환경학회 2005 한국물환경학회지 Vol.21 No.6

In order to treat leachate from aged landfill site effectively, removal of biologically recalcitrant organic matter and denitrification efficiency were evaluated through the combination of $H_2O_2/O_3$ AOP pretreatment process and UASB process. The results can be summarized as follows. In case of leachate having low COD/N ratio from aged landfill site, it is possible to increase available COD for denitrification in nitrate utilizing denitrification and nitrite utilizing denitrification both by enhancing biodegradability of recalcitrant organic matter as applying $H_2O_2/O_3$ AOP to pretreatment process. In this experiment, it is found that available COD for denitrification can be increased to 1.0 and 0.4 g/day, respectively. Comparison has been made between requiring COD and available COD for denitrification in each experimental stages. It is expected that high rate of denitrification can be achieved with leachate from young landfill site because higher amount of available COD for denotrification is present in the leachate than the amount of requiring COD for denitrification. Especially, In leachate from aged landfill site with low COD/N ratio, it can be concluded that denitrification using nitrite nitrogen can enhance overall denitrification performance efficiently because denitrification using nitrite nitrogen requires less amount of carbon source than denitrification using nitrate nitrogen. Comparing the biogas production rate and nitrogen content of biogas under the condition of same amount of nitrate and nitrite addition, biogas production and nitrogen content of biogas are increased during denitrification after $H_2O_2/O_3$ AOP pretreatment process. Therefore, it can be confirmed that COD/N ratio in the leachate is increased. Applying $H_2O_2/O_3$ AOP as pretreatment system of landfill leachate seems to have little economic benefit because it requires additional carbon source to denitrify ammonia nitrogen in leachate coming from aged landfill site. However, it is possible to apply this pretreatment process to leachate from old landfill site in view of AOP process can achieve removal of biologically recalcitrant organic matter and increase of available COD for denitrification simultaneously.

Enhancement of nitrate removal in constructed wetlands utilizing a combined autotrophic and heterotrophic denitrification technology for treating hydroponic wastewater containing high nitrate and low organic carbon concentrations

Park, J.H.,Kim, S.H.,Delaune, R.D.,Cho, J.S.,Heo, J.S.,Ok, Y.S.,Seo, D.C. Elsevier Scientific Pub. Co 2015 Agricultural water management Vol.162 No.-

To enhance the nitrate removal in constructed wetlands (CWs) for treating hydroponic wastewater discharged from greenhouses, the effectiveness of HF (horizontal flow)-HF hybrid CWs utilizing a combined sulfur-based autotrophic (based on the optimum conditions from batch experiment) and heterotrophic denitrification was evaluated for treating hydroponic wastewater containing high nitrate and low organic carbon concentrations. The optimum ratio of sulfur: limestone:immobilized bead with Thiobacillus denitrificans (T. denitrificans) was found to be 3:1:4; the optimum initial cell density was above 1x10<SUP>6</SUP>cells; the optimum temperature was 25-35<SUP>o</SUP>C; and the optimum sulfur sources were thiosulfate and elemental sulfur to effectively treat hydroponic wastewater utilizing autotrophic denitrification with T. denitrificans in batch experiments. In the HF-HF CWs utilizing the combined autotrophic and heterotrophic denitrification, the average removal efficiencies of nitrate were higher in the order of T2 (71.5%, thiosulfate treatment-combination of heterotrophic and autotrophic denitrification) >T3 (66.6%, element sulfur treatment-combination of heterotrophic and autotrophic denitrification) @?T1 (43.0%, control-heterotrophic denitrification only). In the HF-HF CWs, the maximum nitrate removal efficiency by the thiosulfate treatment was slightly greater than that by the treatment with elemental sulfur, whereas the sulfate production influence on autotrophic denitrification by elemental sulfur (SO<SUB>4</SUB><SUP>2-</SUP>: 89.1mgL<SUP>-1</SUP>) was lower as compared to thiosulfate (SO<SUB>4</SUB><SUP>2-</SUP>: 38.3mgL<SUP>-1</SUP>). Because the sulfate production is an important factor to meet acceptable drinking water quality discharge standard (Sulfate concentration in the effluent was below 250 in US EPA, and 200mgL<SUP>-1</SUP> in South Korea), elemental sulfur was a more suitable sulfur source in HF-HF hybrid CWs. Overall, a combined process of using E/L/B (element sulfur/limestone/immobilized bead with T. denitrificans) column in HF-HF hybrid CWs would promote autotrophic and heterotrophic denitrification. Therefore, a combined autotrophic and heterotrophic denitrification process in HF-HF CWs would be more suitable than the heterotrophic denitrification alone (conventional technology in CWs) for treating nitrate in hydroponic wastewater since hydroponic wastewater contains little organic carbon.

전자폐수의 탈질에 있어 다양한 외부탄소원 성능비교 및 미생물 군집변화

송현준,김태근,차현정,정성엽 대한환경공학회 2024 대한환경공학회지 Vol.46 No.2

목적 : 전자폐수의 생물학적 탈질과정에서 다양한 종류의 외부탄소원을 적용한 성능비교와 NGS분석을 통해 탈질전ᆞ후 박테리아 군집변화를 해석하였다. 방법 : 6종류의 외부탄소원을 선정 후 C/N비 4의 무산소 조건에서 6시간 동안 질산성 질소의 농도를 분석하며 탈질속도를 평가하고 NGS분석을 통해 탈질 전ᆞ후 박테리아의 군집분포변화를 확인하였다. 결과 및 토의 : 다양한 외부탄소원의 탈질성능 비교 결과 Ethylene glycol(EG)이 6시간 이후 79.9%로 가장 우수하였으며 비탈질속도(SDNR)는 1.000 mg NO3 --N removal/g MLVSS·hr이었다. NGS를 이용한 박테리아 군집변화는 문(Phylum)수준에서 10개 문이 90% 이상 분포하며 Proteobacteria, Saccharibacteria, Chloroflexi의 순으로 우점 하였고 이 중 Saccharibacteria, Chloroflexi가 탈질에 기여하는 박테리아임을 선행연구 고찰을 통해 간접적으로 확인할수 있었다. 강(Class) 수준에서의 군집분포 해석 결과 투입된 외부탄소원 성상에 따라 실험군간 군집의 차이를 보였으며 γ-proteobacteria의 경우 탄소원을 투입한 실험군에서 모두 증가되었다. 속(Genus) 수준에서 확인된 탈질박테리아 군집비율은 1.27% 미만으로 다양한 박테리아가 탈질에 관여하다는 것을 알 수 있었다. 결론 : Ethylene glycol(EG)의 경우 대체 외부탄소원으로 활용 가능 할 것으로 판단되며 Saccharibacteria, Chloroflexi 와 같은 다양한 박테리아가 탈질에 기여하며 질소오염원 제거에 관여하는 것을 간접적으로 확인하였다. Objectives:In the biological denitrification process of electronic wastewater, the denitrification performance of various types of external carbon sources and the changes in the bacterial community before and after denitrification were evaluated through NGS analysis.Methods:After selecting 6 types of external carbon sources, the concentration of nitrate nitrogen was analyzed for 6 hours under anoxic conditions with a C/N ratio of 4 to evaluate the denitrification rate, and the changes in the community distribution of bacteria before and after denitrification were confirmed through NGS analysis.Results and Discussion:As a result of comparing the denitrification performance of various external carbon sources, Ethylene glycol(EG) was the best at 79.9% after 6 hours, and the specific denitrification rate(SDNR) was 1.000mg NO₃^--N removal/g MLVSS·hr. The bacterial community change using NGS was distributed more than 90% of 10 phylums at the phylum level, and <i>Proteobacteria, Saccharibacteria</i>, and <i>Chloroflexi</i> were dominant, and among them, <i>Saccharibacteria<</i> and <i>Chloroflexi</i> were confirmed to be bacteria contributing to denitrification. At class and genus level, when a external carbon source was added, the number of <i>γ-proteobacteria</i> increased in all experimental conditions, but the distribution of denitrifying bacteria was less than 1.27%, indicating that various bacteria contributed to denitrification. Conclusion:In the case of Ethylene glycol(EG), it is judged that it can be used as an external carbon source, and there was no significant change in the community depending on the type of carbon source injected, and various bacteria such as <i><Saccharibacteria</i> and <i>Chloroflexi</i> contributed to denitrification and eliminated nitrogen pollutants.

Denitrification Potential and Denitrifier Abundance in Downstream of Dams in Temperate Streams

이승훈,정석희,강호정,Vo, Nguyen Xuan Que,Lee, Seung-Hoon,Doan, Tuan Van,Jung, Sokhee P.,Kang, Hojeong 한국미생물학회 2014 미생물학회지 Vol.50 No.2

댐의 존재가 하천 생태계에 미치는 영향을 연구하기 위해 다양한 연구가 지금까지 수행되어 왔지만, 댐이 하류의 탈질화에 미치는 영향은 잘 알려져 있지 않다. 대한민국 낙동강의 댐 원류에서 탈질화 효소 활성도(잠재 탈질율)와 탈질균 분포(nirS, nirK, nosZ 유전자를 표지유전자로 사용)를 조사하였다. 자갈 혹은 모래로 채워진 하천의, 갈대가 우거진 하변지역과 강바닥의 침전물을 채취하여 조사하였다. 이 실험의 가설은 다음과 같다. (i) 하천 침전물의 N과 C의 사용유효량이 높을수록 대조군에 비해 미생물 군집의 탈질화 작용이 더욱 증진한다, (ii) 하천생태계마다 상이하게 나타나는 잠재 탈질율 간의 차이는 탈질 미생물의 양에 비례한다. 30여 년간 댐에 의해 수문학적으로 큰 차이가 있었고 또한 댐 하류의 저서에 무기질소와 용존유기탄소 농도가 대조군에 비해 매우 높았음에도 불구하고, 탈질균 군집의 양과 잠재 탈질율은 하천 간에 큰 차이가 없었다. 하지만 nirS 유전자와 nosZ 유전자의 양과 잠재 탈질율은 댐 하류에 존재하는 자갈이 많은 하변과 모래가 많은 하천 바닥에서 홍수빈도와 계절별 온도변동에 관련하여 크게 증가함을 알 수 있었다. nirK 유전자는 모든 시료에서 발견되지 않았다. Canonical correspondence analysis (CCA) 분석결과는 탈질균 군집 양과 영양염류 가용도와 잠재 탈질율 사이에는 약한 상관관계가 있음을 보여주었다. Various studies have been conducted to investigate effects of dams on river ecosystems, but less information is available regarding damming impacts on downstream denitrification. We measured denitrification enzyme activity (potential denitrification rate) and denitrifier abundances (using nirS, nirK, and nosZ as markers) in dammed headstreams of the Nakdong River in South Korea. Sediments in Phragmites-dominated riparian areas and in-stream areas across streams (dammed vs. reference) with different streambed materials (gravel and sand) were sampled occasionally. We hypothesized that (i) the higher available N and C contents in sediments downstream of dams foster larger denitrifier communities than in the reference system and (ii) differences in potential denitrification rates across the systems correspond with denitrifier abundances. Despite 30 years of different hydrological management with dams and greater inorganic N and DOC contents in sediments downstream of dams, compared to the references, abundances of denitrifier communities and potential denitrification rates within the whole sediment were not significantly different across the systems. However, nirS and nosZ denitrifier abundances and potential denitrification rates were considerably increased in specific sediments downstream of dams (gravelly riparian and sandy in-stream) with regard to flooding events and seasonal temperature variation. nirK was not amplified in all sediments. Canonical correspondence analyses (CCA) revealed that the relationship between abundances of denitrifier communities and nutrient availabilities and potential denitrification rates was a weak one.

Denitrification rates and community structure of denitrifying bacteria in newly constructed wetland

Song, K.,Lee, S.H.,Kang, H. Gauthier-Villars ; Elsevier Science Ltd 2011 European journal of soil biology Vol.47 No.1

Constructed wetlands are generally created for water quality amelioration using natural biogeochemical processes including denitrification. To have maximal denitrification rates in constructed wetlands, both optimal environmental conditions and activation of denitrifiers are required. In this study, we monitored temporal dynamics of the community structure of denitrifying bacteria by terminal restriction fragment length polymorphism (T-RFLP) in newly constructed wetlands over 2 growing seasons. We also measured denitrification rates and denitrifying enzyme activity (DEA) using an acetylene blocking method. Community structure of denitrifying bacteria differed between 2 years, and dominant T-RFs changed over the period. In addition, the composition of denitrifying bacteria became simplified in the second year. Along with changes in community structure of denitrifying bacteria, DEA increased substantially in the second year compared with that in the first year. This result suggests that several dominant and active denitrifiers may induce higher potential for denitrification as wetlands became stabilized. However, actual denitrification rates did not exhibit an annual difference, but were more strongly influenced by environmental conditions such as temperature, pH, and DOC concentrations. Overall results of this study indicate that active denitrifiers may dominate and denitrification potentials increase as a newly constructed wetland becomes stabilized, but actual denitrification rates are mainly constrained by environmental conditions such as temperature, pH and carbon availability.

지중환경 내 지질 매체가 질산염의 탈질 반응에 미치는 영향에 대한 고찰

전지훈,이우춘,이상우,김순오 한국지하수토양환경학회 2020 지하수토양환경 Vol.25 No.특별호

Nitrate contamination has received much attention at local as well as regional scales. The domestic situation is not out ofexception, and it has been reported to be very serious, particularly within agricultural areas as a result of excessive usageof nitrogen fertilizers. Meanwhile, nitrate can be naturally attenuated by denitrification in subsurface environments. Thedenitrification occurs through biotic (biological) and abiotic processes, and numerous previous studies preferentiallyfocused the former. However, abiotic denitrification seems to be significant in specific environments. For this reason, thisstudy reviewed the previous studies that focused on abiotic denitrification processes. Firstly, the current status of nitratecontamination in global and domestic scales is presented, and then the effect of geological media on denitrification isdiscussed while emphasizing the significance of abiotic processes. Finally, the implications of the literature review arepresented, along with future research directions that warrant further investigations. The results of previous studiesdemonstrated that several geological agents could play a vital role in reducing nitrate. Iron-containing minerals such aspyrite, green rust, magnetite, and dissolved ferrous ion are known to be powerful electron donors triggering denitrification. In particular, it was proven that the rate of denitrification by green rust was comparative to that of biologicaldenitrification. The results indicate that abiotic denitrification should be taken into account for more accurate evaluation ofdenitrification in subsurface environments.

연구보문 : 토양환경 ; 황입자를 이용한 독립영양탈질에서의 아질산성질소 탈질 조건 탐색

강우창 ( Woo Chang Kang ),오상은 ( Sang Eun Oh ) 한국환경농학회 2010 한국환경농학회지 Vol.29 No.3

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 탈질미생물의 최적 성장 조건을 찾고자 하였다. 초기 알칼리도가 충분한 조건에서는 아질산성질소 탈질 저해가 관찰되지 않았으며 실험온도가 20℃인 경우에도 30℃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. Swine wastewater contains high amounts of organic matter and nutrients (nitrogen and phosphorus). The biological nitrogen removal can be achieved by nitrification and denitrification processes. Nitrification-denitrification can be performed via nitrite which is called as the short-cut process. This Short-cut process saves up to 25% of oxygen and 40% of external carbon during nitrification and denitrification. In this study, the batch tests were conducted to assess the different parameters for the nitrite sulfur utilizing denitrification, such as alkalinity, temperature, initial nitrite concentration, and dissolved oxygen. The experimental results showed that the nitrite removal efficiency of the reactor was found to be over 95% under the optimum condition (30℃ and sufficient alkalinity). Autotrophic nitrate denitrification was inhibited at low alkalinity condition showing only 10% removal efficiency, while nitrite denitrification was achieved over 95%. The nitrite removal rates were found similar at both 20℃ and 30℃. In addition, nitrite removal efficiencies were inhibited by increasing oxygen concentration, but sulfate concentration increased due to sulfur oxidation under an aerobic condition. Sulfate production and alkalinity consumption were decreased with nitrite compared those with nitrate.

완효성 탄소원 정제 내 citric acid의 생물학적 탈질소화 영향

한경진,염여훈,김영,권수열 한국지하수토양환경학회 2022 지하수토양환경 Vol.27 No.3

This study utilized citric acid as a floating agent in biological denitrification process and assessed its role under differentcarbon supplying conditions. Several microcosm tests including citric acid active (CAA), precipitating tablet release active(PTRA) and floating tablet release active (FTRA) were conducted to evaluate nitrate denitrification efficacy. In CAAreactors, nitrate removal was accompanied by the formation of denitrification by-products such as nitrite and nitrous oxide,with the extent of nitrate removal being proportional to citric acid concentration. These results suggest that citric acidinduced heterotrophic biological denitrification. PTRA reactor that incorporated CAA and the same electron donor showeda similar denitrification efficiency to CAA reactor. FTRA reactor, which contained the same amount of fumarate as PTRA,enhanced denitrification by 7% as compared to the PTRA reactor. The overall results of this work indicate that surpluscitric acid can be efficiently utilized in heterotrophic denitrification.

강화도 갯벌 퇴적물의 산소요구량과 탈질소화의 계절 변화

안순모,An, Soon-Mo 한국해양학회 2005 바다 Vol.10 No.1

2001년 12월부터 2004년 4월까지 강화도 남서부에 위치한 동막 및 여차리 갯벌에서 계절별로 퇴적물의 산소요구량과 탈질소화를 측정하여 퇴적물의 유기물 분해와 질소 영양염의 제거과정을 살펴보았다. 퇴적물 산소 요구량 (SOD;sediment oxygen demand)은 니질 함량이 높은 동막이 평균 $683\;{\mu}mole\;m^{-2}h^{-1}$이었고, 사질 함량이 높은 여차리에서 평균 $457\;{\mu}mole\;m^{-2}h^{-1}$로 동막에서 높은 값을 보였다. SOD는 여름철에 높고, 겨울철에 낮은 경향을 보였는데, 2002년 4월에는 산소가 퇴적물에 의해 소비되기보다는 생산되어 저서성 규조류에 의한 광합성이 활발함을 알 수 있었다. 탈질소화도 동막이 높고 여차리가 낮았는데, 그 값은 각각 5.4와 $3.4\;{\mu}mole\;m^{-2}h^{-1}$이며, 유기물로는 $9.3\;mg-C\;m^{-2}d^{-1}$과 $5.9\;mg-C\;m^{-2}d^{-1}$에 해당하는 양이다. 염습지를 포함한 연안 퇴적물의 탈질소화율은 $0{\sim}200{\mu}mo1e\;m^{-2}h^{-1}$의 범위에 있는데, 본 조사의 값은 낮은 편에 속했다. 탈질소화가 낮은 것은 갯벌이 유기물 농도가 높은 환경임에도 불구하고 분해하기 쉬운 신선한 유기물은 부족하여 전반적인 유기물 분해율이 낮은 것으로 사료된다. 이는 평소에는 낮은 탈질소화를 보이나, 고농도의 유기물이 유입되면, 이를 효과적으로 제거할 잠재적 능력이 있음을 시사한다. 산소요구량과 무기탄소 용출량을 통해 살펴본 강화갯벌의 유기물 순분해율(net remineralization rate)은 동막이 평균 $196\;mg-C\;m^{-2}d^{-1}$이고 여차리가 평균 $132\;mg-C\;m^{-2}d^{-1}$이었다. Seasonal variations of remineralization and inorganic nitrogen removal capacity were measured from Dec. 2001 to Apr. 2004 in a tidal flat located in south-western pan of Gwanghwa island, Korea by measuring the sediment oxygen demand (SOD) and denitrification. SOD was higher in muddy sediment (Dong-Mak; three year average=$683;m^{-2}d^{-1}$) than sandy sediment(Yeocha; three year average=$457;m^{-2}d^{-1}$). The SOD was high in summer and tended to be lower in winter. During the sediment incubation in Apr. 2002, production of oxygen from sediment was observed implying active benthic photosynthesis. Denitrification was also higher in muddy sediment (Dong-Mak: $5.4;m^{-2}d^{-1}$) than sandy sediment (Yeocha; $3.4;m^{-2}d^{-1}$). The denitrification rate corresponds to the carbon remineralization rate of 9.3 and $5.9\;mg-C\;m^{-2}d^{-1}$ in Dong-Mak and Yeocha, respectively. The denitrification rates were lower compared to rates observed in other coastal area $(0{\sim}200\;{\mu}mole\;m^{-2}h^{-1})$. Although Kwanghwa tidal flat sediments are replete in organic matter, remineralization activity seems to be limited by the availability of labile organic matter. The Kwangwha tidal flat may have potential to effectively remove large load of organic matter. Net remineralization rates were 196 and $132\;mg-C\;m^{-2}d^{-1}$ in Dong-Mak and Yeocha, respectively.