To isolate aerobically and identify the diversity of halophilic bacteria in the soil around two ports, Daepopogu and Hwasun Port, on Jeju island, a total 46 halophilic bacteria strains were isolated and phylogenetically analysed. The isolated strains were divided into 3 phyla, 8 families, 16 genera and 23 species. The main taxa was the Bacilli class, which included 50.0% of the strains with 3 families, 10 genera and 15 species of Bacillaceae, Exiguobacterium_f and Planococcaceae. The second taxa was the Gammaproteobacteria class, which included 45.7% of the strains with 4 families, 5 genera and 7 species of Aeromonadaceae, Halomonadaceae, Marinobacteraceae and Vibrionaceae. The isolated strains were tested for hydrolytic enzymes, amylase, lipase and protease activity, and 31 strains showed activity of at least one enzyme. Furthermore, auxin activity was determined in 7 strains. This study showed that the isolated strains have possible applications in the food and agricultural industries and have importance as a genetic resource in Korea.

The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.

In the general process of design for aerobic digestion, the design for field plant of which inflow pattern is continuous inflow is performed using the results from lab scale batch reactor. However, the recent researchers reported that the general designs were performed as over-estimated, Therefore, in this study, laboratory batch experiments were carried out at $20^{\circ}C$ and pH 7.5 on the aerobic digestion of waste activated sludge at different solid levels. This treatise could consider the negligence about effective digestion periods the usage of VSS as solid concentration, and the effect of initial solid concentration of solid degration rate coefficient($k_d$) as reasons of the overestimated design, and showed the scheme of how to design for aerobic digestion from batch experiment.

The purpose of this experimental research was focused to improve the quality of the effluent and the yielded sludge when the papermill wastewater was treated by the indirect aerated submerged biofilter as a second treatment method of papermill wastewater. Changing the various experimental factors(Nutrient additions or not, HRT, F/M ratio, recirculation ratio, etc) with indirect aerated biofilter, the results obtained are as follows. 1. Because of the microbes concentration could be sustained to $9,000mg/l$ in submerged biofilter and then the volumetric organic loads could be increased to $2.7kg-BOD/m^3/day$(that of activated sludge is $0.8kg-BOD/m^3/day$), the reactor volume can be reduced to one third of the activated sludge treatment. 2. Because of the yield coefficient(Y) and the endogenous decay coefficient(kd) were revealed 0.4 and 0.07/d, the yielded sludge volume was reduced by for compared with that of the activated sludgg process. 3. The concentration of the sloughed sludge in the reactor was 2.62~4.01%, so the thickener could be omitted in the papermill wastewater sludge treatment process. 4. When the operating was conducted at HRT of 4hrs, the treatment efficiencies of BOD and COD were obtained 80% and 70%, Therefore operating time can be reduced to one half of the activated sludge treatment.

In this study, the treatment of livestock wastewater using an aerobic granular sludge based sequencing batch reactor was investigated. The reactor operation was carried out by general injection and split injection methods. The average removal efficiency of organic matter after the adaptation period was 71.5 and 87.4%, respectively. Some untreated organic matter was attributed to recalcitrant organic matter. The average removal efficiency of total nitrogen was 65.6 and 88.4%, respectively. These results indicate that the denitrification reaction by split injection was carried out smoothly. As for the solids, the ratio of aerobic granular sludge/mixed liquor suspended solid can be determined as the main factor of the process operation, and the ratio increased gradually and finally reached 86.0%. Correspondingly, the sludge volume index (SVI) was also improved, reaching 54 mL/g at the end of operation, and it is believed that the application of a short settling time contributed to the improvement of settleability.

In this study, the effect on the stability of Aerobic Granular Sludge (AGS) caused by an AGS separator was investigated. The AGS separator was a hydrocyclone. The main factors of the AGS separator were filter pore size (0.125∼0.600 mm), conical-to-cylindrical ratio (1.5∼3.0), and operating time (1∼20 min). The AGS/mixed liquor suspended solid (MLSS) ratio gradually increased to 0.500 mm (AGS/MLSS: 84.3±3.0%). AGS was best separated at the conical-to-cylindrical ratio of 2.5 (AGS/MLSS: 84.7±3.3%). As the operating time increased, the AGS separation performance also tended to increase. The shortest AGS separator run time, but the highest AGS separation performance was 10 min (87.0±2.5%). AGS stability was evaluated by operating the selected AGS separator and sequencing batch reactor. The average removal efficiencies of TOC, TCODCr, SS, TN, and TP were 95.7%, 96.9%, 93.0%, 89.0%, and 96.2%, respectively, which met the effluent standards in Korea. In addition, the AGS/MLSS ratio tended to remain constant, and the sludge volume index demonstrated a tendency to decrease from 140 mL/g to 70 mL/g. During the operation, the particles of AGS in optical microscope observations gradually increased.

In this study, the effect on the stability of Aerobic Granular Sludge (AGS) with different Carbon/Nitrogen (C/N) ratios was investigated. The C/N ratios were controlled to 10.0, 7.5, 5.0, and 2.5 using the sequencing batch reactor, and the results showed that the removal efficiency of organic matter and total nitrogen decreased simultaneously with the decrease of C/N ratio. The removal efficiency of organic matter and total nitrogen at C/N ratio of 2.5 was 70.7% and 52.3% respectively. In addition, the AGS/mixed liquor suspended solids (MLSS) ratio showed a tendency to decrease from 85.7% to 73.7%, while the sludge volume index showed a tendency to increase from 82 mL/g to 102 mL/g as the C/N ratio decreased. At the same time, the apparent deviation of polysaccharide (PS) content in extracellular polymeric substances was observed, and polysaccharides/protein (PS/PN) ratio decreased from 0.62 to 0.31 as the C/N ratio decreased. Optical microscope observations showed that the reduction in C/N ratio caused the growth of filamentous bacteria and significantly affected the stability of AGS.

This study evaluated the biosorption properties of calcium ion using Aerobic Granular Sludge (AGS). A sequencing batch reactor was used to induce the production of Extracellular Polymeric Substances (EPS) through salinity injection, and the calcium ion adsorption efficiency was analyzed by a batch test. The EPS contents showed significant changes (104-136 mg/g MLVSS) at different salinity concentrations. The calcium ion adsorption efficiency was highest for AGS collected at 5.0% salinity, and it was confirmed that the biosorption efficiency of AGS was increased owing to the increase in EPS content. The results of the Freundlich isotherms showed that the ion binding strength (1/n) was 0.3941-0.7242 and the adsorption capacity (Kf) was 2.4082-3.3312. The specific surface area and the pore size of the AGS were 586.1 m2/g and 0.7547 nm, respectively, which were not significantly different from each other. It was confirmed that the influence of biological properties, such as EPS content, was relatively large among the factors affecting calcium ion adsorption.

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.

The purpose of this study was to evaluate the effect of high-salinity wastewater on the microbial activity of Aerobic Granule Sludge (AGS). Laboratory-scale experiments were performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen removal efficiency, sludge precipitability, and microbial activity were evaluated under various salinity injection. The COD removal efficiency was found to decrease gradually to 3.0% salinity injection, and it tended to recover slightly from 4.0%. The specific nitrification rate was 0.043 0.139 mg NH4 +-N/mg MLVSS·day. The specific denitrification rate was 0.069 0.108 mg NO3 --N/mg MLVSS·day. The sludge volume index (SVI30) ultimately decreased to 46 mL/g. The specific oxygen uptake rate decreased from an initial value 120.3 to a final value 70.7 mg O2/g MLVSS·hr. Therefore, salinity injection affects the activity of AGS, causing degradation of the COD and nitrogen removal efficiency. It can be used as an indicator to objectively determine the effect of salinity on microbial activity.

The purpose of this study is to biological treatment of high salinity wastewater using Aerobic Granular Sludge (AGS). In laboratory scale’s experiments research was performed using a sequencing batch reactor, and evaluation of the denitrification reaction in accordance with the injection condition of salinity concentration, surface properties of microorganisms, and sludge precipitability was performed. The results showed that the salinity concentration increased up to 1.5%, and there was no significant difference in the nitrogen removal efficiency; however, it showed a tendency to decrease gradually from 2.0% onward. The specific denitrification rate (SDNR) was 0.052 0.134 mg NO3 --N/mg MLVSS (mixed liquor volatile suspended solid)·day. The MLVSS/MLSS (mixed liquor suspended solid) ratio decreased to 76.2%, and sludge volume index (SVI30) was finally lowered to 57 mL/g. Using an optical microscope, it was also observed that the initial size of the sludge was 0.2 mm, and finally it was formed to 0.8-1.0 mm. Therefore, salinity injection provides favorable conditions for the formation of an AGS, and it was possible to maintain stable granular sludge during long-term operation of the biological treatment system.

The purpose of this study was to confirm the applicability of aerobic granular sludge (AGS) in the advanced sewage treatment process. Simulated influent was used in the operation of a laboratory scale reactor. The operation time of one cycle was 4 h and the reactor was operated for six cycles per day. The volume exchange ratio was 50%. The influent was injected in divisions of 25% to increase the removal efficiency of nitrogen in every cycle. As a result, the removal efficiencies of CODCr and TN in this reactor were 98.2% and 76.7% respectively. During the operation period, the AGS/MLVSS concentration ratio increased from 70.0% to 86.7%, and the average SVI30 was 67 mL/g. The SNR and SDNR were 0.073 0.161 kg NH4 +-N/kg MLVSS/day and 0.071 0.196 kg NO3 --N/kg MLVSS/day respectively. These values were higher or similar to those reported in other studies. The operation time of the process using AGS is shorter than that of the conventional activated sludge process. Hence, this process can replace the activated sludge process.

The amount of sewage sludge that is emitted is gradually increasing every year. However, since 2012, because of the London Protocol, the oceanic dumping of sewage sludge has been prohibited. Therefore, for recycling organic waste, either the ground disposal method has to be used or technological solutions that develop energy from such waste have to be identified. Heat is generated when the sewage sludge has decomposed by aerobic microbes. In this study, to dehydrate sewage sludge, heat was applied and the drying efficiency was evaluated according to the air flow rate (AFR) and the proportional mixing of the returned sludge. For the experiments, returned sludge that was dried to 40% moisture content was used; consequently, the highest temperature was obtained when the moisture content was 30% and, for maintaining aerobic conditions, the optimal AFR was 200 ml/min·kg. During biodrying for 14 days, the highest temperature of reactor was 46℃, which was maintained at higher than 40℃ for 5-7 days; moreover, 18.8% of moisture was eliminated. These results show that using biodrying for treating sewage sludge has economic potential compared to hot-air drying; moreover, with additional treatment, biodrying can be one of the methods for producing Bio Solid Refuse Fuel (Bio-SRF).

우리나라 유기성 폐기물처리의 가장 큰 비중을 차지하던 해양투기 방법이 폐기물 해양배출을 금지하는 런던협약으로 인해 2012년부터 해양투기가 전면 금지됨에 따라 안정적이고 지속적인 육상처리 시설이 요구되고 있다. 환경부는 폐기물 관리법으로 온실가스 발생 억제 및 재활용 촉진을 위하여 유기성 슬러지의 직매립을 금지하였다. 그동안 유기성 폐기물을 자원화하기 위한 방법으로 퇴비화 기술이 많이 연구되어 왔으나 여러 가지 문제점들이 야기되고 있다. 소각방법은 다이옥신과 같은 2차 오염의 우려가 있으며, 퇴비화 과정에서는 발생되는 악취로 인하여 민원이 잦아지고 결국 퇴비화 시설이 폐쇄되는 경우가 많았다. 우리나라에서 쓰이고 있는 퇴비화는 비 연속식 처리로 퇴비 원료(유기성 폐기물)의 제한적 처리와 퇴비화 활성에 요구되는 시간이 길어 부지요구도가 높은 문제, 불안정한 최종 생성물, 감량화 실패, 장시간 온도조절 및 공기주입으로 인한 에너지 소비증가로 상용화에 어려움이 많다. 본 연구에서는 강릉시 하수종말처리장에서 배출되는 하수슬러지를 대상으로, 초고온 호기성 발효과정을 통해 하수슬러지의 퇴비화 진행에 따른 온도변화, 발효가스 분석, pH, C/N비, 수분함량, 고형물 유기물 변화, 부피 및 무게변화, 중금속 분석, 혼합 및 교반과 같은 반응인자들을 도출하여 운전 변수를 알아보았다. 한편 하수슬러지의 퇴비화 진행에 따른 시료와 발효 종료된 퇴비의 중금속 및 유해인자 분석을 통하여 퇴비의 발효 메커니즘 및 안정성을 검증하였다. 초고온 퇴비화 기술의 새로운 정립과 국내 연구가 전무한 초고온 발효공정의 data base 확보를 목적으로 하였다. 또한 퇴비화 과정에서 발생되는 악취도와 악취를 발생시키는 원인물질을 밝히고자 하였다.