• 한국물환경학회지
• /
• 제22권1호
• /
• pp.134-139
• /
• 2006

Partial nitirification and denitrification process has been reported to be technically feasible and economically favorable, especially for wastewater treatment with high ammonium concentration or low Carbon/Nitrogen ratio. This research was performed to survey nitrite accumulation by nitritation in treating ADEPT effluent of piggery wastewater, which contains highly concentrated ammonia. To estimate the possibility of nitrite accumulation, DO concentration and SRT were investigated as key operational parameters. This result proved that nitritation to nitrite was steadily obtained under short sludge retention time. Oxygen limitation was proved to be just a subsidiary parameter. Energy efficiency of nitritation-denitritation process was higher than complete nitrification-denitrification because external carbon requirement for denitritation could be saved. Though the influent contained significant nonbiodegradable organic substrate, total nitrogen removal efficiency was more than 51% in nitritation-denitritation system.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2001년도 춘계학술대회 논문집
• /
• pp.187-191
• /
• 2001

In the paper, an approach to the development of the selective catalytic reduction process of NOx is presented. The reduction process can be efficiently controlled using a conventional combination of feed-forward and feed-back control structures. The aim of this paper is to test and verify an approach to the SCR process which is based on an industrial pilot plant of combustion and nitric oxide formation. The systems are based on measurements of a NOx removal ratio and the fuel flow rate, and NH$_3$slip which are usually available as a part of de-NOx control system.

• 생태와환경
• /
• 제34권2호통권94호
• /
• pp.133-139
• /
• 2001

이 연구는 식물플랑크톤(Scenedesmus sp.)이 영양염류를 흡수하는 원리를 이용하여, 영양염류를 제거하기 위하여 실시하였다. 식물플랑크톤을 교반하여 배양할 경우, 가장 빨리 증식되었고, 오수방류수를 식물플랑크톤 배양액에 50% 되도록 혼합하여, 약 2일 동안 배양시키는 것이 영양염류를 제거하는데 효율적이었다. 이러한 최적조건에서 증식된 식물플랑크톤을 GF/C glass fiber filter로 여과하여 분석한 결과, TKN는 88% 이상 제거되었고, DIP는 70${\sim}$80% 제거되었으며, 이때 식물플랑크톤이 최대한 1300mg/m$^{3}$로 증식되었다. 또한, 3시간 간격으로 영양염류의 이용과정을 분석한 결과, 식물플랑크톤의 증식은 NH$_{3}$-N(r$^{2}$=0.96)와 DIP(r$^{2}$=0.92)와는 높은 상관관계를 보였다. 영양염류를 섭취하여 증식된 식물플랑크톤을 여과시키거나, 동물플랑크톤에 적용시켜 먹이연쇄 관계를 이용한다면, 생태공학적으로 영양염류를 제거할 수 있고, 수계의 부영양화를 방지할 수 있을 것으로 사료된다.

• 한국물환경학회지
• /
• 제29권1호
• /
• pp.1-6
• /
• 2013

This study was focused on improving nitrification efficiencies of M-dephanox (Modified-Dephanox) process. Rotating biological contactor (RBC) was used instead of floating sponge type media in nitrification reactor. High ammonia removal efficiencies were observed in nitrification reactor, regardless of organic loading from contactor of M-dephanox process. Denitrification efficiencies were also increased to maintain low $NO_3-N$ concentration in effluent. This enhanced phosphate release in anaerobic contactor and resulted in high removal efficiencies of phophorus. Average removal efficiencies of $TCOD_{Cr}$ and $SCOD_{Cr}$ were 93.8% and 81.6%, respectively, while those of TKN and ${NH_4}^+-N$ were 80.9% and 74.4%, respectively. As for phosphorous treatment, the average removal efficiencies of TP and OP were 94.7% and 94.3%, respectively. Also, effect of operating temperature on nitrogen removal was examined. Average removal efficiency of TN was 65.8 % at $15^{\circ}C$ or below (at average temperature of $13.3^{\circ}C$), while that was 82.8% at $15^{\circ}C$ or above (at average temperature of $21.9^{\circ}C$).

• Environmental Engineering Research
• /
• 제11권3호
• /
• pp.134-142
• /
• 2006

The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system was investigated. Anaerobic digestion of swine wastewater gave volatile solids (VS) removal efficiencies of 43.3%, 52.1% and 54.5% for hydraulic retention times (HRTs) of 20, 30, 40 days, respectively. The removal efficiencies of VS, total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) decreased with increasing VS volumetric loading rate (VLR). Higher organic removal efficiency was observed at longer HRTs for the same VS volumetric loading rate. As VS volumetric loading rate increased, biogas production increased and the methane content of the biogas decreased. Experiments using duckweed (Lemna species) as an aquatic macrophyte gave the following results. In the case of nitrogen, removal efficiency was above 60% and effluent concentration was below 10.0 mg/L when the influent ammonia-N loading was about $1.0\;g/m^2/day$. In the case of phosphorus, removal efficiency was above 55% and effluent concentration was below 2.0 mg/L when the influent $PO_4$-P loading was about $0.15\;g/m^2/day$. In addition, crude protein and phosphorus content of duckweed biomass increased from 15.6% to 41.6% and from 0.8% to 1.6%, respectively, as the influent nutrient concentration increased. The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system offers good performance in terms of organics and nutrient removal for relatively low operation and maintenance costs. The results indicate that under appropriate operational conditions, the effluent quality is within the limits set by Korean discharge criteria.

• Environmental Engineering Research
• /
• 제25권3호
• /
• pp.309-315
• /
• 2020

Slaughterhouse wastewater (SWW) is characterized as one of the most harmful agriculture and food industrial wastewaters due to its high organic content. The emissions of SWW would cause eutrophication of surface water and pollution of groundwater. This study developed a pilot scale anaerobic-aerobic slaughterhouse wastewater treatment process (AASWWTP) to enhance the chemical oxygen demand (COD) and total nitrogen (TN) removal. The optimum supernatant reflux position and ratio for TN removal were investigated through the modified Box-Behnken design (BBD) experiments. Results showed that COD could be effectively reduced over the whole modified BBD study and the removal efficiency was all higher than 98%. The optimum reflux position and ratio were suggested to be 2 alure and 100%, respectively, where effluent TN concentration was satisfied with the forthcoming Chinese discharge standard of 25 mg/L. Anaerobic digestion and ammonia oxidation were considered as the main approaches for COD and TN removal in the AASWWTP. The results of inorganic nutrients (K⁺, Na⁺, Ca²⁺ and Mg²⁺) indicated that the SWW was suitable for biological treatment and the correspondingly processes such as AASWWTP should be widely researched and popularized. Therefore, AASWWTP is a promising technology for SWW treatment but more research is needed to further improve the operating efficiency.

• 한국환경과학회지
• /
• 제11권6호
• /
• pp.577-582
• /
• 2002

Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increased with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850$\^{C}$ of optimal condition.

• 한국입자에어로졸학회지
• /
• 제9권4호
• /
• pp.239-246
• /
• 2013

The purpose of this study is to determine the feasibility of dry-type desulfurization process for actual application to coal-fired power plant. We used actual exhaust gas from Facility Y, Plant #2 to fabricate a demo-scale testing device to attempt to improve the efficiency of desulfurization. A spout-bed circulating dry scrubber convergence system connecting turbo reactor with bag filter was devised, then analyzed for performance characteristics of $SO_2$ removal for Ca/S mole ratio, superficial gas velocity, and ammonia injection, and for secondary reaction characteristics of the non-reactive sorbent at the bag filter. As a result, the installation of spout-bed circulating dry scrubber convergence system showed better economy and efficiency for removing sulfur than the existing wet/semidry-type desulfurization process. In addition, the best efficiency for desulfurization occurred when connected to the bag filter, with differential pressure maintained at 150 $mmH_2O$.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.398-401
• /
• 2003

Bacillus species predominantly outgrown in a night soil treatment system were isolated and characterized. Cell interactions took place among them and cell population changed under various culture conditions. Maximum removal of $NH_4\;^+-N$ and cell production occurred under the conditions of 30% DO and C/N ratio of 8. Additions of 0.8% peptone and 0.3% yeast extract to a basal medium influenced the growth of isolates and the removal of $NH_4\;^+-N$ in flask culture, and metal ions such as Ca, Fe and Mg also did. During the flask experiment of nitrogen removal under an aerobic condition, active nitrification by the isolates occurred largely in 1 h with the decrease of COD and alkalinity destructed was only 74.6% of theoretical value. From the nitrogen balance, the percentage of nitrogen lost in the flask culture was estimated to be 29.0%. This conversion of ammonia to $N_2$ under an aerobic condition was confirmed by GC analysis. The B3 process using the Bacillus species seemed to have some economic advantage.

• 에너지공학
• /
• 제13권2호
• /
• pp.133-143
• /
• 2004

Simultaneous removal technology of particulate/NOx/SOx/HCl using CuO/3Al$_2$O$_3$ㆍ2SiO$_2$catalyst impregnated ceramic candle filters is an advanced air pollution process and provides significantly to reduce hazardous gases emitted from coal-fired power plant. This process uses a high-temperature catalytic filter for integrating SOx and HCl reduction through injection an alkali sorbent (such as hydrated lime or sodium bicarbonate), NOx removal through ammonia injection and selective catalytic reduction (SCR), and particulate collection on the catalytic filter surface. The advantages of the process include : compact integration of the emission control technologies into a single component; easy handling of dry sorbent and by-product; and improved SCR catalytic life due to lowered SOx, HCl and particulate levels. CuO/3Al$_2$O$_3$ㆍ2SiO$_2$ catalyst impregnated ceramic candle filters showed a possibility of simultaneous treatment from results which have ascertained high removal efficiency at various combined gases conditions, and in pilot plant test for 3 months, NO conversion was showed 90% over.