• 한국물환경학회지
• /
• 제29권3호
• /
• pp.393-399
• /
• 2013

To control organic matters, it needs to manage not only biodegradable organic matters but also refractory organic matters. Refractory organic matters from municipal wastewater, industrial wastewater, non-point sources and etc., have been continuously discharged to the near watersheds. It is estimated that the refractory organic matter ratios are continuously increased in waterbody. In watersheds of the Total Maximum Daily Loads (TMDLs), it was investigated that COD/BOD ratios increased in many unit watersheds of the 4 major river basins. The portions COD/BOD ratios increased were found to be a 97% of Geum River unit watersheds, a 81% of Yeongsan/Seumjin River unit watersheds, a 78% of Nakdong River unit watersheds, a 70% of Han River unit watersheds, respectively. Therefore, it has become important for establishment of effective management strategies to control refractory organic matter in watersheds of the Total Maximum Daily Loads (TMDLs). In order to properly manage organic matters including refractory organic matters, the present organic indicator (BOD) has to be converted to TOC (or COD). Compared to COD and BOD, TOC, as a organic matter indicator, is evaluated more appropriate.

• 공업화학
• /
• 제16권3호
• /
• pp.366-371
• /
• 2005

본 연구에서는 methylene blue의 오존 산화하는 동안 BOD, COD, TOC, 흡광도 그리고 탈색 비율을 분석하였으며, 오존산화반응은 methylene blue가 충진되어 있는 원형모양의 반응기에서 수행한 결과 다음과 같은 결론을 얻었다. 탈색도는 최대파장(${\lambda}_{max}$, 660 nm)에서 흡광도를 측정하였다. 오존농도는 $50{\pm}10mg/L$를 사용하였으며 40 min 후 거의 오존산화반응이 끝났다. 그 결과로 $30^{\circ}C$에서 오존산화 반응 후 $TOC/TOC_0$ 비율은 83.8%로 나타났고, COD는 초기값보다 44.0% 감소하였다. 그리고 $BOD_5/COD$ 비율은 64.2%에서 90.8%로 오존산화 반응 후 생분해도가 증가하는 것으로 나타났다. 반응속도상수는 $3.30{\times}10^{-2}min^{-1}$로 나타났으며, 활성화 에너지는 $3.01kcal{\cdot}mol^{-1}$로 나타났다.

• 한국폐기물자원순환학회지
• /
• 제35권7호
• /
• pp.653-659
• /
• 2018

In the industrial wastewater that occupies a large proportion of river pollution, the wastewater generated in textile, leather, and plating industries is hardly decomposable. Though dyeing wastewater has generally been treated using chemical and biological methods, its characteristics cause treatment efficiencies such as chemical oxygen demand (COD) and suspended solids (SS) to be reduced only in the activated sludge method. Currently, advanced oxidation technology for the treatment of dyeing wastewater is being developed worldwide. Electro-coagulation is highly adapted to industrial wastewater treatment because it has a high removal efficiency and a short processing time regardless of the biodegradable nature of the contaminant. In this study, the effects of the current density and the electrolyte condition on the COD removal efficiency in dyeing wastewater treatment by using electro-coagulation were tested with an aluminum anode and a stainless steel cathode. The results are as follows: (1) When the current density was adjusted to $20A/m^2$, $40A/m^2$, and $60A/m^2$ under the condition without electrolyte, the COD removal efficiency at 60 min was 62.3%, 72.3%, and 81.0%, respectively. (2) The removal efficiency with NaCl addition was 7.9% higher on average than that with non-addition at all current densities. (3) The removal efficiency with $Na_2SO_4$ addition was 4.7% higher on average than that with non-addition at all current densities.

• 한국미생물·생명공학회지
• /
• 제23권6호
• /
• pp.763-769
• /
• 1995

As a mean to recover photosynthetic bacterial(PSB) cells and its practical uses in food industrial wastewater treatment, various biodegradable polyelectrolytes were first investigated for flocculation of suspended colloids in the PSB treatment process of soybean curd wastewater. Anionic polyelectrolytes such as sodium alginate and carrageenan were not effective but a cationic polyelectrolyte chitosan isolated from Portunus trituberclatus showed very effective flocculation activity. The concentration of chitosan, pH and temperature of wastewater for maximal flocculation were 40 mg/l, pH 7 and room temperature, respectively. Test using deacetylated chitosan to various degree showed higher flocculating activities in samples deacetylated over 75% and time for maximum flocculation was 40 min by stirring slowly under the above optimal conditions. Chitosan was not only effective to flocculate cells but also removed COD and MLSS of the wastewater. COD of 42% and MLSS of 87% were removed by addition of chitosan to the soybean curd wastewater treated with PSB.

• 환경위생공학
• /
• 제13권1호
• /
• pp.44-56
• /
• 1998

This study was performed to investigate the reaction characteristics of piggery wastewater for biological nutrient removal. The reaction characteristics were discussed the fraction of organics, the behavior of nitrogen, nitrification, denitrification, and the behavior of phosphorus. The fraction of readily biodegradable soluble COD was 11-12 percent. The ammonia nitrogen was removed via stripping, nitrification, autotrophic cell synthesis, and heterotrophic cell synthesis. The removal percents by each step were 12.1%, 68.9%, 15.0%, and 4.0%, respectively. Nitrification inhibition of piggery wastewater was found to occur at an influent volumetric loading rate over 0.2 NH$_{3}$-N kg/m$^{3}$/d. Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent. The phosphorus removed was released in the form of ortho-p in the aerobic fixed biofilm reactor, it was caused by autooxidation. The synthesis and release of phosphorus were related to the ORP and the boundary value for the phase change was about 170mV. In the synthesis phase, the phosphorus removal rate per COD removed was 0.023mgP$_{syn}$/mgCOD$_{rem}$. The phosphorus contents of the microorganism were 4.3-6.0% on a dry weight basis.

• Environmental Engineering Research
• /
• 제17권2호
• /
• pp.59-63
• /
• 2012

This paper proposes a modified Ludzack-Ettinger (MLE) type membrane bioreactor (MBR) as a method of treatment for wastewater from food waste disposer. Micro-membrane filtration allows for an extremely low concentration of suspended solids in the effluent. The effluent of the reactor in question is characterized by a relatively high level of non-biodegradable organics, containing a substantial amount of soluble microbial products and biomass. Results obtained in this paper by measurement of membrane fouling are consistent with biomass concentration in the reactor, as opposed to chemical oxygen demand (COD). The MLE process is shown to be effective for the treatment of wastewater with a high COD/N ratio of 20, resulting in are markedly high total nitrogen removal efficiency. Denitrification could be improved at a higher internal recycle ratio. Despite the low concentration of influent phosphorus, the phosphorus concentration of the outflow is seen to be relatively high. This is because outflow phosphorous concentration is related to COD consumption, and the process operates at along solids retention time.

• 대한환경공학회지
• /
• 제31권8호
• /
• pp.649-654
• /
• 2009

산소소비속도 측정에 의한 미생물 호흡률 분석방법에 의해 하수의 유기물질과 미생물 분율을 평가하였다. 하수의 유기물과 미생물 분율은 생물학적 공정의 모델링을 위한 중요한 기초자료이다. 본 연구에서 하수의 유기물 분율을 측정한 결과, 미생물에 의해 분해가 빠른 유기물, 분해가 느린 유기물, 분해되지 않는 용존성 유기물, 분해되지 않는 고형 유기물과 종속영양미생물의 분율은 각각 26.6%, 41.5%, 8.5%, 14.7% 및 8.7%였다. 또한, 질소 분율을 측정한 결과, 질산성 질소, 암모니아성 질소, 용존성 비분해 유기성 질소, 용존성 분해 유기성 질소 및 분해가 느린 유기성 질소의 분율은 각각 약 3.7%, 64.9%, 4.7%, 9.4% 및 17.4%였다.

• 한국환경보건학회지
• /
• 제40권2호
• /
• pp.137-146
• /
• 2014

Objectives: Feasibility of electrochemical oxidation of the aqueous non-biodegradable wastewater such as cationic dye Rhodamine B (RhB) has been investigated in an electrochemical reactor with solid polymer electrolyte (SPE). Methods: Nafion 117 cationic exchange membrane as SPE has been used. Anode/Nafion/cathode sandwiches were constructed by sandwiching Nafion between two dimensionally stable anodes (JP202 electrode). Experiments were conducted to examine the effects of applied current (0.5~2.0 A), supporting electrolyte type (0.2 N NaCl, $Na_2SO_4$, and 1.0 g/L NaCl), initial RhB concentration (2.5~30.0 mg/L) on RhB and COD degradation and $UV_{254}$ absorbance. Results: Experimental results showed that an increase of applied current in electrolysis reaction with solid polymer electrolyte has resulted in the increase of RhB and $UV_{254}$ degradation. Performance for RhB degradation by electrolyte type was best with NaCl 0.2 N followed by SPE, and $Na_2SO_4$. However, the decrease of $UV_{254}$ absorbance of RhB was different from RhB degradation: SPE > NaCl 0.2 N > $Na_2SO_4$. RhB and $UV_{254}$ absorbance decreased linearly with time regardless of the initial concentration. The initial RhB and COD degradation in electrolysis reaction using SPE showed a pseudo-first order kinetics and rate constants were 0.0617 ($R^2=0.9843$) and 0.0216 ($R^2=0.9776$), respectively. Conclusions: Degradation of RhB in the electrochemical reactor with SPE can be achieved applying electrochemical oxidation. Supporting electrolyte has no positive effect on the final $UV_{254}$ absorbance and COD degradation. Mineralization of COD may take a relatively longer time than that of the RhB degradation.

• 한국물환경학회지
• /
• 제20권3호
• /
• pp.197-205
• /
• 2004

Batch test methods have developed for a long time to measure kinetic and stoichiometric parameters which are required to perform steady state design and mathematical modelling of activated sludge processes. However, at various So/Xo ratios, abnormal behaviors of ordinary heterotrophic organism in batch tests have been reported in many researches. Thus, in this research, abnormal behaviors of heterotrophs in batch tests were investigated at various So/Xo conditions by measuring and interpreting oxygen utilization rate. As So/Xo ratio increased, the calculated values of maximum specific growth rates, ${\mu}_{H,max}$ and $K_{MP,max}$, increased. However, at a certain point of So/Xo (around 10mgCOD/mgMLAVSS), ${\mu}_{H,max}$ and $K_{MP,max}$ values started to decrease. According to this observation, three prominent behaviours of heterotrophs were identified at various So/Xo conditions. (1) At low So/Xo region (below 5 mgCOD/mgMLAVSS), the oxygen utilization rate of heterotrophs in batch tests were almost stable and consequently yielded lower maximum specific growth rate. (2) At high So/Xo region (up to 5~10 mgCOD/mgMLAVSS), oxygen utilization rate incresed sharply with time and indicated more upward curvature than the predicted OUR with conventional activated sludge model, which consists of single hetetrotrophs group. Thus, in this region, competition model of two organisms, fast-grower and slow-grower, seemed to be appropriate. (3) At extremely high So/Xo region (over 10mgCOD/mgMLAVSS), significant oxygen utilization rate was still observed even after depletion of readily biodegradable COD. This might be caused by retarded utilization of intermediates which were generated by self inhibition mechanism in the process of RBCOD uptake.

• 한국산학기술학회논문지
• /
• 제19권5호
• /
• pp.64-71
• /
• 2018

본 논문은 호기성 생분해도를 통하여 유가공 폐수의 기질특성을 파악하기 위하여 수행되었다. 유기물 중 빨리 분해되는 물질(Ss)은 SCODcr 기준을 84.2 %로 조사되었는데, 이는 수산물 가공폐수의 75.8~77.9 %, 돈사폐수의 58.2 % 보다 높은 것으로 조사되었다. 생물학적 분해 불가능한 용존성 유기물(SI)의 비율은 5.6~6.4 %로, 미생물 신진대사에 의해 발생 되는 inert 물질 비율(SIi)은 3.6~3.7 %로 조사되었다. 생물학적 분해 불가능한 용존성 유기물 성분의 함유 계수(YI) 0.092~0.099로, 미생물 신진대사로 생성되는 inert 물질의 생성계수(Yp)는 0.039~0.040으로 산정되었다. 유기물 성분 계수 분석결과, 유가공 폐수의 용존성 유기물 약 91.0 %가 생물학적으로 분해 가능한 물질이고, 이중 약 92.5 %가 빨리 분해되는 Ss 성분으로 조사되었다. 또한 총유기물(TCODcr) 중에 생물학적 분해 가능한 유기물의 비율은 89.3 %로 조사되었다. 생물학적 분해 불가능한 용존성 유기물(SI) 성분은 3.0 %, 생물학적 분해 불가능한 부유성 물질(XI) 성분은 7.7 %로 비교 대상 폐수보다 낮게 조사되었는데, 이는 유가공 폐수가 호기성 생분해도가 크다는 것을 의미한다.