This study was intended to evaluate the removal efficiency of nutrients in effluents of wastewater using microalgae. Microalgae used in the culture experiment collected in stream and reservoir located in Gyeongsangbuk-do. Dominant species in prior-culture tank were Monoraphidium contortum, Scenedesmus acutus, Coelastrum microporum and Chlorella sp. Dominant species in synthetic wastewater culture under the 4000 Lux and 8000 Lux were Chlorella sp. and Scenedesmus obliquus. The removal efficiency of NO3-N under the 4000 Lux and 8000 Lux were 27.2%~88.1% and 63.0%~83.6% respectively. The removal efficiency of PO4-P under the 4000 Lux and 8000 Lux showed above 93%. Removal efficiency of nutrients of 1.0×106 cells mL-1 inoculation concentration was more higher than that of nutrients of 1.0×105 cells mL-1 and 1.0×107 cells mL-1 inoculation concentration. Microalgae cultured in synthetic wastewater removed 94.9% of TN and 90.0% of TP. The removal rate of TN and TP in synthetic wastewater were 1.961 mg L-1 day-1 and 0.200 mg L-1 day-1 respectively. Nutrient removal efficiency of microalgae according to kinds of wastewater showed the highest in the private sewage.

This study was performed to develop a new process technology for advanced wastewater treatment using a modified Rotating Activated Bacillus Contactor (RABC) process that adopts anoxic-oxic suspended biomass tanks to enhance nutrients removal. A modified lab-scale RABC process was applied to examine its applicability and to obtain the design factors for the optimum operation of the system. The modified RABC process showed a little more stable and high nutrients removal efficiency than the prototype RABC process: about 70% of nitrogen and 55% of phosphorous removal when the low organic loading (influent COD 200mg/L). However, the processing efficiency of nutrients removal rates was enhanced to great extent when high organic loading: nitrogen 90% and phosphorous 85% (influent COD 500mg/L). High organic loading stimulated extremely good biomass attachment on the reticular carrier RABC stage and the excellent nutrients removal, nevertheless with almost no offensive odor.

에너지 소비의 증가와 화석 연료의 감소로 인해 바이오디젤과 같은 재생 가능한 대체 에너지 자원이 관심을 받고 있다. 미세조류를 이용한 바이오디젤은 기존의 농작물과 경쟁하지 않는 것과 더불어 많은 장점을 갖고 있다. 본 연구에서는 미세조류 배양의 생산 비용 절감과 축산 폐수 처리라는 두 가지 목표를 충족시키지 위해 돈분 액체 비료를 사용하였다. 옥외 배양 시스템(Small Scale Raceway Pond; SSRP)과 희석된 돈분 액체 비료를 이용하여 단일 미세조류 Chlorella sp. JK2, Scenedesmus sp. JK10 과 혼합 토착 미세조류 CSS를 20일 동안 각각 배양하였다. 미세조류 혼합균주인 CSS의 바이오매스 생산과 지질 생산성은 각각 1.19±0.09 g L-1, 12.44±0.38mg L-1 day-1로 단일 종에 비해 2배 이상 높았다. 돈분 액체 비료의 TN, TP의 제거율 역시 혼합 토착 미세조류 CSS에서 93.6%, 98.5%로 단일 종의 이용에 비해 30% 이상 높은 제거 효율을 보여주었다. 이를 통해 돈분 액체 비료는 미세조류 배양에 필요한 N과 P를 제공하며, 미세조류를 이용한 SSRP를 통하여 영양염류를 제거할 수 있는 가능성을 확인하였다. 또한 미세조류 배양을 위한 생산 비용의 감소로 경제성 있는 바이오디젤의 생산 가능성을 확인하였다.

0.4μm의 세공크기를 갖고 있는 평막이 침지된 연속회분식 반응기에서 유입 유기물 농도가 영양염류 제거에 미치는 영향을 조사하였다. 분리막의 여과성능과 영양염류 제거효과를 규명하기 위하여 유입 유기물의 농도를 200 mg/L (Run-1), 400 mg/L (Run-2) 및 800 mg/L (Run-3)로 연속적으로 변화시키면서 실험하였다. COD/N 및 COD/P의 비가 증가할수록 T-N 및 T-P의 제거율은 모두 증가하였다. Run-1, Run-2 및 Run-3에서 T-N의 평균 제거율은 각각 28.1, 32.6 및 90.4%이었으며, 투과수의 T-N 평균 농도는 각각 32.0, 30.0 및 4.3 mg/L 이었다. 또한 Run-1, Run-2 및 Run-3에서 T-P의 평균 제거율은 각각 13.6, 35.3 및 93.1%이었으며, 투과수의 T-P 평균 농도는 각각 3.11, 2.33 및 0.25 mg/L이었다.

비점오염원으로부터 오염된 소하천에서 영양염류를 제거하기 위하여 식물플랑크톤 배양 장치를 설치하고 운영하였다. 식물플랑크톤 배양조에서 식물플랑크톤 정치배양 결과, 식물플랑크톤의 연속배양을 위한 배양조의 체류시간을 3일로 결정하였으며 TP는 70%, TN은 44%가 제거됨을 확인하였다. 연속배양 결과 45일 동안 배양조에 유입된 TP의 53.9%, TN의 53.1%가 식물플랑크톤에 의한 흡수와 슬러지로 제거되었다. 식물플랑크톤이 성장하면서 배양조의 pH와 용존산소농도는 각각 평균 10.8, 16mg L-1이었다. 결국 비점오염원에 오염된 하천수의 영양 염류는 식물플랑크톤의 사체와 화학반응으로 생성된 침전물로 제거되었다. 비교적 설치가 간단하고 경제성이 높은 식물플랑크톤 배양법의 높은 현장적용 가능성을 확인하였다.

본 연구는 우리나라 습지의 주요 우점종인 갈대, 줄 및 애기부들을 대상으로, 자연습지에서 생육기 중에 시기와 횟수를 달리하여 지상부를 제거하는 것이 생산력과 영양염류 제거능에 미치는 영향을 규명하고자 하였다. 지상부 제거는 세 종 모두에서 지상부 생산력과 영양염류 흡수량을 증가시켰으며, 최대효과를 위한 시기와 횟수 및 효과의 정도는 종에 따라 차이를 보였다. 즉, 갈대는 1차년도 실험에서 6월 제거구의 연총생산력이 1,014g/m2로서 대조구의 1

영양염류의 농도와 수리학적체류시간에 따른 달뿌리풀의 질소ㆍ인 흡수 실험 결과로서 NH4-N, NO3-N, PO4-P의 흡수량은 각각 체류시간에 따라 유의한 영향을 미쳤으며(F=44.93, 95.52, 12.70, Pm2, 평균 수질농도 0.308 NH4-N, 1.461 NO3-N, 0.348 PO4-P mg/L, 체류시 간 1일~ 5일 범위에서 1 m2 1일 기준의 흡수량이 각각 7.31~20.15 NH4

Bioremediation has been recognized as a suitable alternative to conventional methods of removing contaminants, and it uses fungi, bacteria and microalgae. In contrast to other organisms, microalgae are unique in that they have the ability to perform photosynthesis like plants and to utilize organic/inorganic carbon substrates, in a process called phytoremediation. Microalgae can populate a reaction site rapidly and enhance the bioremediation efficiency. In this study, Chlorella vulgaris was used to evaluate the removal potentials of the nutrients (N and P) and heavy metals (Cu and Zn) from swine wastewater. The optimum growth conditions for Chlorella vulgaris and the removal potentials of N, P, Cu, and Zn from synthetic wastewater using Chlorella vulgaris were investigated. Based on the results, the applicability of this microalga to on-site wastewater treatment was examined. Optimal growth conditions for Chlorella vulgaris were established to be 28℃, a pH of 7, and light and dark cycles of 14:10 h. As the concentrations of the nutrients were increased, the efficiencies of N and P removal efficiencies by Chlorella vulgaris were decreased in the single and binary mixed treatments of the nutrients, respectively. Further, the efficiencies of Cu and Zn removal also decreased as the heavy metals concentrations added were increased, both in the single and binary mixed treatments. In addition, the efficiency of Cu removal was higher than that of Zn removal. Our results indicate that Chlorella vulgaris could be used in treatment plants for the removal of nutrients and heavy metals from swine wastewater.

MEPC. 227(64)가 발의되면서 해상에서 선박 배출수의 오염에 대한 규제가 강화되었다. 특히 T-P에 대하여 유입수 대비 유출수의 제거율을 1.0 mg/L 또는 80%로 제한하고 있다. 이를 충족시키기 위해 SBR+MBR 공정을 적용하여 시험운전을 진행하였으며, 그에 따른 문헌조사 결과 생물학적 처리만으로 인의 목표 처리효율을 충족시키는 것에 한계가 있을 것으로 판단하여 응집제(PAC 5)를 도입하였다. 따라서 본 연구는 PAC 5를 이용한 응집공정 적용시 T-P의 제거율이 어떻게 변화하는지 연구하는 데에 그 목적이 있다. 실험에 사용된 원수는 실험을 위해 자체 제작한 화장실에서 발생된 오수를 사용하였으며 원수의 T-P 농도는 33.215 mg/L로 측정되었다. 실험은 총 3 사이클 동안 진행되었으며, SBR+MBR 공정을 거친 1차 유출수의 T-P 농도 및 제거율의 평균값과 PAC 5를 이용하여 응집공정까지 시행된 2차 유출수의 T-P 농도 및 제거율의 평균값을 비교하였다. 실험 결과 1차 유출수의 평균 T-P 농도는 15.05 mg/L로 유입수 대비 유출수가 70.8%의 제거율로 나타났고, 또한 2차 유출수의 경우 평균 농도 3.47 mg/L로 93.3%의 제거율로 나타났다. 실험을 통해 PAC 5를 적용한 응집공정을 실시하였을 때 T-P 평균 제거율이 22.5%가 상승한 것으로 확인되었다. 따라서 SBR+MBR 공정을 적용한 고도수처리장치에 있어서 PAC 5를 이용한 응집공정 적용은 긍정적인 것으로 판단된다.

The effect of the variation of aeration time on the removal of organics, nitrogen and phosphorus using synthetic wastewater was investigated in sequencing batch reactors (SBRs) which included DNPAOs and DNGAOs. The cycling times in four SBRs were adjusted to 12 hours and then included different aerobic times as 1 hr, 2.5 hr, 4 hr and 5.5 hr, respectively. Four SBR systems have been operated and investigated for over 40 days. Average TOC removal efficiencies were about 71 % in all SBRs. The NH_4^+-N removal efficiency was increased as the increase of aeration time. After changing aeration time, the total nitrogen removal efficiencies of SBRs were shown as 35 %, 85 %, 75 % and 65 %, respectively. Higher phosphorus release and uptake were occurred as the decrease of the aeration time. After all, the overall phosphorus removal efficiency decreased and the deterioration of phosphorus removal was occurred when aeration time was over 4 hr. Denitrification in aerobic conditions was observed, which showed the presence of DNPAOs and DNGAOs. In batch experiments, PAOs were shown as the most important microorganisms for the phosphorus removal in this experiment, and the role of DNGAOs was higher than that of DNAPOs for the nitrogen removal.

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P, and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

HRP(high rate pond) which had kept the manufactured clay of 3㎝-thickness as benthic clay in reactor and the 6 flat-blade turbine as impeller for agitation was named HRASP(high rate algae stabilization pond). And the experiment for treatment of artificial synthesis wastewater containing COD : 300㎎/ℓ. , NH3-N : 30㎎/ℓ, T-P : 9㎎/ℓ. as nutrients was been performed successfully. This reactor was been operated under conditions : 24 hrs.-irradiation and water temperature, 25℃ and pH 7 and agitation velocity, 15, 30, 45rpm and the effect of agitation velocity on algal bioaccumulation of nutrients was been studied with view point of fluid dynamics. The next followings could be obtained as results. 1. The agitation with a turbine impeller blade in HRASP makes clay particle indicate superior suspension effect by means of forming of excellent curl/shear flow in reactor. 2. The excessive suspension of clay particle which is created at 45rpm as rotation velocity of impeller blade of turbine disturbs the light penetration and algal photosynthesis reaction. 3. Efficiencies for removal of nutrients come out as COD : 93.9%∼94.3%, (NH3-N + NO3-N) : 81.9%-99.0%, T-P : 46.8%-53.6%. 4. Kuo values of K1 for algal growth come out seperately as 15rpm : 1.876×10-2, 30rpm : 4.618×10-3. 5. Kuo values of K2 for removal of N, P come out seperately as 15rpm : 8.403×10-1 and 1.397×10-1, 30rpm : 4.823×10-1 and 2.052×10-1. 6. It can be guessed easily that the excessive agitation can inhibit the algal and bacterial symbiotic reaction if it is considered that micro organism' sense to preservation of life is relied on natural function of metabolism. Therefore the studies for this matter should be followed continuously.

In this study, the removal possibility of nutrients of T-P, NH3-N, NO3-N, and T-N is examined through a positive experimental study using submerged biofilter of media packing channel method. From the analysis of nutrients removal efficiency for each run of the collected sample, following results are obtained. Firstly, the result of N/P surveying for inflow shows serious value that excess the limit value of 20 as the values are in the range of 12.0∼42.7 and the average is 25.73. Secondly, the highest concentration of the incoming NH3-N reaches double of the standard since the concentrations of NH3-N, and NO3-N for inflow shows 0.06㎎/ℓ , and 2.5∼3.8㎎/ℓ respectively, and the average removal rate which passed the submerged biofilter adopted in this study is a satisfactory level. Next, the average removal rate of T-P of 51.5% shows the possibility of entrophication removal since the removal rate of T-P of 66.8∼68.8% in relative low temperature period of RUN 1∼2 appeared higher than in RUN 3∼6, and T-N shows relatively poor result with the average removal rate of 34.1%. And it is known that the bigger BOD/P and BOD/N are, the more removal rate increases from the examination result of the relation between BOD/P and BOD/N, and the treatment water T-P and T-N to decide the relation with the concentration of organic matters, and thought that the appropriate proportion is necessary for effective removal of nitrogen and phosphorus.