• Environmental Engineering Research
• /
• 제18권4호
• /
• pp.267-276
• /
• 2013

This study presents a comparison of different protocols for the synthesis of iron-loaded zeolites, and the results of their application, as well as that of zeolite-A (Z-A), to the removal of ammonium and phosphate from aqueous media. Zeolites prepared by three methods were evaluated: iron-incorporated zeolites (IIZ), iron-exchanged zeolites (IEZ), and iron-calcined zeolites (ICZ). The optimal iron content for preparing of IIZ, as determined via scanning electron microscopy and X-ray photoelectron spectroscopy analyses, expressed as molar ratio of $SiO_2:Al_2O_3:Fe$, was below 0.05. Ammonia removal revealed that the iron-loaded zeolites have a higher removal capacity than that of Z-A due, not only to ion-exchange phenomena, but also via adsorption. Greater phosphate removal was achieved with IEZ than with ICZ; additionally, no sludge production was observed in this heterogeneous reaction, even though the coagulation process is generally accompanied by the production of a large amount of undesired chemical sludge. This study demonstrates that the developed synthetic iron-loaded zeolites can be applied as a heterogeneous nutrient-removal materials with no sludge production.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2001년도 봄 학술발표회 논문집
• /
• pp.585-590
• /
• 2001

Physicochemical phenomena in soils are dependent upon pH when using electrokinetic extraction for the contaminants removal especially for heavy metals. pH variation in soils is affected on H$\^$+/ and OH￣ ions produced by electrolysis reaction and buffer capacity of soil. High amount of heavy metals are retained in the soils if the soil buffer capacity remains high enough to resist a change in pH. Therefore, accurate pH estimation of soil is important in the application of electrokinetic mechanism for decontamination and understanding of subsurface physicochemical characteristics is also required as well as considering buffer capacity for the enhanced methods application. For these, buffer capacity and pH distribution were measured for the four soils, and also compared with modeling results. The results of buffer modeling were good agreement with experimental data. It is showed that four soils were effected by buffer capacity

• 상하수도학회지
• /
• 제26권2호
• /
• pp.209-218
• /
• 2012

Recently, as reinforced water quality standards for wastewater has been announced, more efficient and more powerful wastewater treatment processes are required rather than the existing activated sludge process. In order to meet this demands, we evaluate Task 1-4 about lab scale $A_{2}O$　process using biofilm media. Task 1, 2, and 3 use 'Module A' which has 4 partitions (Anoxic/Anerobic/Oxic/Oxic). Task 4 uses 'Module B' which has 2 partitions including a denitrification reactor with an Inclined plug flow reactor (IPFR) and a nitrification reactor with biofilm media. The denitrification reactor of Module B is designed to be upward flow using IPFR. The result of evaluating at each Task has shown that attached growth system has better capacity of removal efficiency for organic matter and nitrogen with the exception of phosphorus.　Task 4 which has the most outstanding removal efficiency has 90.5% of $BOD_{5}$ removal efficiency, 97.8% of ${NH_4}^{+}-N$ removal efficiency, 65% of T-N removal efficiency and 92% of T-P removal efficiency with additional chemical phosphorus removal system operated at HRT 9hr, Qi:Qir 1:2, and BOD/T-N ratio 2.7.

• 환경위생공학
• /
• 제5권1호
• /
• pp.83-92
• /
• 1990

Adapting two step aeration system to a waste water treatment of W-paper manufactory as Full-Scale Plants, we drew a following conclusion from its practical working. 1. Because BOD removal efficiency was 20% in A-Stage, 90% in B-Stage and total removal efficiency was 97%. It worked treatment plant well and was suitable for effluent water standard as well. Because COD removal efficiency was 42% in A-stage, 71% in B-stage and the total removal efficiency was 94% COD control was possible in effluent water quality. 2. Treatment efficiency according to a load capacity was average 20% in 1.401 BOD kg/m3/d load of A-Stage and average 90% in 0.273 BOD kg/$\textrm {m}^3$ / d load of B-Stage. 3. Treatment efficiency according to a ratio of F/M was 2.657--5.024 kg BOD/kg MLSS/d in A-Stage and BOD removal efficiency was 16-261 in the same stage. The ratio of F/M was 0.068-0.094 kg BOD /kg MLSS/d and BOD removal efficiency ratio was 85-94%. Therefore treatment efficiency could be kept stably and volume of aeration tank could be reduced wholly. 4. Treatment efficiency according to MLSS appeared BOD 20%. COD 42%, in A-Stage and removal efficiency appeared BOD 90%, COD 71% in B-Stage. They were suitable for plan condition. 5. Because of working of complemented treatment plant by AB-Process. 20,000,000 Won a month was saved than the ordinary working cost. Therefore, it was assumed that invested cost could be recollected in 19 months or so consequently.

• 환경정책연구
• /
• 제9권2호
• /
• pp.41-55
• /
• 2010

댐은 사회전반에 걸쳐 많은 편익을 제공하고 있다. 이를 위해서는 일정수준 이상의 저수용량 확보가 필수적이다. 그러나 상류의 토사 유입으로 인하여 댐의 저수용량은 줄어들고 있는 실정이다. 전 세계적으로 5조 톤의 토사가 매년 댐 뒤에 쌓이는 실정이다. 강이 여러 지역에 걸쳐 흐르는 경우 상류의 농업에서 발생하는 토사는 장시간에 걸쳐서 지속적으로 발생하기 때문에 상류 농업종사자들은 관리를 소홀히 하는 경향이 있다. 특히 토사는 댐의 저수용량을 지속적으로 줄여 궁극적으로는 댐의 경제적 가치를 소멸시키는 효과가 있다. 따라서 상류 지역의 토사저감 노력과 함께 댐의 저수용량 확보가 급선무이다. 실증분석으로 나일강 상류의 수단 농업지역과 하류의 이집트 Aswan High Dam을 분석하였다. 실증분석 결과 상류 농업부문의 토사저감 노력과 댐의 토사제거 방안이 사회전체의 경제적 편익을 극대화하는 것으로 나타났다. 동태적 최적제어이론을 이용한 유역토사관리 모형에서 댐의 경제적 편익을 포함한 사회전체의 편익은 크게는 약 1,510억 달러로 추산되었다.

• Environmental Engineering Research
• /
• 제11권5호
• /
• pp.285-291
• /
• 2006

Biofiltration is a simple, effective, economically viable and the most widely used gas treatment technique for treating malodors at low concentrations and high flow rates. This paper reports the performance of two lab scale immobilized cell biofilters operated in continuous mode for hydrogen sulfide ($H_2S$) and ammonia ($NH_3$) removal. The removal efficiency (RE, %) and the elimination capacity (EC, $g/m^3{\cdot}hr$) profiles were monitored by subjecting the biofilters to different loading rates of $H_2S$ (0.3 to $8\;g/m^3{\cdot}hr$) and $NH_3$ (0.3 to $4.5\;g/m^3{\cdot}hr$). The removal efficiencies were greater than 99% when inlet loading rate to the biofilters were upto $6\;gH_2S/m^3{\cdot}hr$ and $4\;gNH_3/m^3{\cdot}hr$ respectively. The performance of the biofilters were also ascertained by conducting shock loading studies at a loading rate of $10\;gH_2S/m^3{\cdot}hr$ and $6\;gNH_3/m^3{\cdot}hr$. The results from this study show high removal efficiency, good recuperating potential and stability of the immobilized microbial consortia to transient shock loads.

• 한국토양환경학회지
• /
• 제1권2호
• /
• pp.51-60
• /
• 1996

본 연구에서는 산업폐기물로 버려지는 hematite와 ferrite를 이용하여 Mn-EDTA와 불소의 제거에 대한 실험을 행하였다. 제거율을 비교, 평가하기 위하여 무기오염물에 대하여 우수한 흡착능을 가지는 것으로 알려진 Na-bentonite를 실험에 포함하였다. Batch형태의 실험 결과, 망간에 대하여 여러 초기농도에서 ferrite-A는 48∼65 %, ferrite-B는 46∼57 %, hematite 의 경우 17∼26%o의 제거율을 갖는 것으로 나타났으며, Na-bentonite의 경우, 10∼23%의 제거율을 나타냈다. 불소의 경우에는 hematite가 53∼63%의 제거율을, ferrite-A가 54∼63%, ferrite-B는 20∼38%를 보였다. 연구 결과 Hematite와 Ferrite가 가지고 있는 특히 complex ion을 형성하는 무기 오염 물질 제거능이 Na-bentonite 보다 우수한 것으로 나타났다. 결론적으로 이러한 산화 광물과 Na-Bentonite 의 혼합을 통하여 차수재로서의 Na-bentonite의 역할을 증진시킬 수 있을 것이다.

• 한국물환경학회지
• /
• 제23권6호
• /
• pp.850-862
• /
• 2007

This study was carried out to survey the actual conditions of wastewater treatment facilities to obtain basic data for the management of wastewater from industrial complexes in Chungcheongnam-do province. Wastewater production flow per site area by watersheds was $49.2m^3/km^2/d$ for Sapgyoho, $8.1m^3/km^2/d$ for Anseongcheon, $5.7m^3/km^2/d$ for Seohae, and $2.9m^3/km^2/d$ for Geumgang. Sapgyoho showed 75% of the total production flow, which was the highest value, Geumgang showed 4% of total flow, which was the lowest value. Average total extra rate as production flow/capacity flow in the wastewater treatment facilities for industrial complex is 49%. Considering by watersheds, the extra rates of Seohae, Geumgang, Anseongcheon, and Sapgyoho, are 73%, 65%, 62%, and 33% respectively. This means that the design of capacity flow in wastewater treatment facilities was too large. Effluent concentration of wastewater treatment facilities did not exceed discharge limit mostly. The removal efficiency rate for water quality item was 90% in BOD, 70% in COD, 80% in SS, 30 to 80% in TN, and 20 to 90% in TP, so the organic removal was good, but the nutrient removal was low and interval of variation was high. The removal efficiency rate of the agricultural was industrial complexes is lower than the national and local complexes. The construction cost of the wastewater treatment facilities in Chungcheongnam-do was $1,756Won\;per\;m^3$, treatment cost was $189Won\;per\;m^3$, and they were about two times and 1.2 times higher than the nation-wide cost, respectively. The treatment cost consists of 39% for man power, 21% for chemical, 16% for power, 11% for sludge treatment, and 13% for others.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2019년도 정기학술대회 발표논문집
• /
• pp.134-134
• /
• 2019

Utilization of organic waste as a renewable energy source is promising for sustainability and mitigation of climate change. Pyrolysis converts organic waste to gas, oil, and biochar by incomplete biomass combustion. Biochar is widely used as a soil conditioner and adsorbent. Biochar adsorbs/desorbs metals and ions depending on the soil environment and condition to act as a nutrient buffer in soils. Biochar is also regarded as a carbon storage by fixation of organic carbon. Phosphorus (P) and nitrogen (N) are strictly controlled in many wastewater treatment plants because it causes eutrophication in water bodies. P and N is removed by biological and chemical methods in wastewater treatment plants and transferred to sludge for disposal. On the other hand, P is an irreplaceable essential element for all living organisms and its resource (phosphate rock) is estimated about 100 years of economical mining. Therefore, P and N recovery from waste and wastewater is a critical issue for sustainable human society. For the purpose, intensive researches have been carried out to remove and recover P and N from waste and wastewater. Previous studies have shown that biochars can adsorb and desorbed phosphates implying that biochars could be a complementary fertilizer. However, most of the conventional biochar have limited capacity to adsorb phosphates and nitrate. Recent studies have focused on biochar impregnated with metal salts to improve phosphates and nitrate adsorption by synthesizing biochars with novel structures and surface properties. Metal salts and metal oxides have been used for the surface modification of biochars. If P removal is the only concern, P adsorption kinetics and capacity are the only important factors. If both of P and N removal and the application of recovery are concerned, however, P and N desorption characteristics and bioavailability are also critical factors to be considered. Most of the researches on impregnated biochars have focused on P removal efficiency and kinetics. In this study, coffee waste is thermally treated to produce biochar and it was impregnated with Mg/Al to enhance phosphates and nitrate adsorption/desorption and P bioavailability to increase its value as a fertilizer. Kinetics of phosphates and nitrate adsorption/desorption and bioavailability analysis were carried out to estimate its potential as a P and N removal adsorbent in wasewater and a fertilizer in soil.

• Korean Chemical Engineering Research
• /
• 제51권2호
• /
• pp.272-278
• /
• 2013

퇴비공장 또는 공공시설에서 발생되는 악취폐가스의 대표적인 제거대상 오염원인 암모니아를 포함한 악취폐가스를 처리하기 위하여 여러 운전 조건 하에서의 광촉매반응기와 바이오필터로 구성된 하이브리드시스템을 운전하였다. 암모니아 총 제거효율은 하이브리드시스템의 운전부하가 운전 단계별로 커졌음에도 불구하고 약 80%로 유지되었다. 광촉매반응기에서의 암모니아 제거효율은 광촉매반응기로의 암모니아 유입부하량이 증가함에 따라서 광촉매반응기의 암모니아 제거효율은 65%에서 약 22%로 감소하였다. 같은 암모니아 유입부하량일지라도 암모니아농도가 클 때보다 적은 경우에 광촉매반응기의 암모니아 제거효율이 상대적으로 높았다. 반면에 바이오필터의 경우는 운전 전반부에는 암모니아 처리효율이 현저하게 억제되었으나 광촉매반응기의 경우와 반대로 시간이 경과하면서 암모니아 유입부하량이 증가함에도 불구하고 바이오필터의 암모니아 제거효율은 지속적으로 약 78%까지 증가하여서 Lee 등의 연구결과에서의 암모니아 제거효율과 비슷하게 도달하였다. 광촉매반응기에 의한 최대 암모니아 제거용량($EC_{PR}$)은 약 16 g-N/$m^3$/h 이었고, 바이오필터에 의한 암모니아 제거용량($EC_{BF}$)은 운전 초기에 암모니아 총 부하가 작은 경우에는 암모니아 총 부하증가에 따른 $EC_{BF}$의 증가추세가 미약하였으나 운전 후반부에 암모니아 총 부하가 큰 경우에는 암모니아 총 부하증가에 따른 $EC_{BF}$의 증가추세가 급격하게 커졌다. 하이브리드시스템 운전 6단계에서 암모니아 총 부하가 약 80 g-N/$m^3$/h일 때에 광촉매반응기에서의 $EC_{PR}$은 약 16 g-N/$m^3$/h이었고, 2차 공정이고 주공정인 바이오필터에 걸리는 암모니아 부하는 나머지인 약 64 g-N/$m^3$/h이고 주공정인 바이오필터의 $EC_{BF}$은 약 48 g-N/$m^3$/h로 산출되었다. 이러한 바이오필터의 암모니아 제거용량은 Kim 등의 연구결과로서 최대 암모니아 제거용량인 1,200 g-N/$m^3$/day와 거의 비슷하였다.