• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.383-390
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• 2011

In this study, a process combined biofiltration with sulfur-utilizing autotrophic denitrification and membrane separation was proposed to examine the efficiency of nitrogen removal. As an experimental device, hollow-fiber module was installed in the center of reactor to generate the flux forward sulfur layer in the cylinder packed with granular sulfur. In addition, a simple module was installed in activated sludge aeration tank which inside and outside of sulfur-using denitrification module was covered with microfilter and the module was considered as an alternative of clarifier. The experiment for developing new MBR process was carried out for three years totally. As the results of first two-year experiment, successful nitrogen removal performance was revealed with lab-scale test and pliot scale plant using artificial wastewater and actual plating wastewater. In this year, pilot scale test using actual domestic wastewater was performed to prove field applicability. As the results, high-rate nitrogen removal performance was confirmed with about 0.19 kg ${NO_3}^--N/m^3$ day of rate. Also significant fouling and pressure increase were not found during the experiment. And, the production ratio of sulfate and the consumption ratio of alkalinity showed a slightly higher value about 311 mg ${SO_4}^{2-}/L$ and 369 mg $CaCO_3$/L, respectively. In conclusion, the developed MBR process can be utilized as an alternative for retrofiting existing wastewater plants as well as new construction of advanced sewage wastewater treatment plants, with cost-effective merit.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.175-179
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• 1979

One of the major problems in tile activated sludge system has been difficulty in separating the microbial solids from the treated effluent and in returning them to the aeration tank. Another problem has been the digestion of the excess activated sludge. In constrast, it has not been difficult to separate the microbial solids from the treated effluent from the biological fixed-film systems(RBC process, Trickling Filter, FAST process). These systems have also featured less sludge production. Recently, it was proposed to experiment with the RESMAS process in order to eliminate the settling tank and sludge concentration facilities and to reduce the quantity of excess sludge for final disposal. The effluent quality could be predicted by .the concept of the maximum accumulation capacity. However, the hydraulic characteristics of the screen media in the RESMAS reactor were not dynamic. The object of the present study is to evalute the sludge accumulation rate and effluent quality prediction in the REMSMAS process designed in the dynamic hydraulic structure. This process can eliminate the final sedimentation tank and sludge concentration tank needed in the RBC, CMAS, Trickling Filter and FAST processes. Also, the effluent quality is desirable to compare with other processes. It appeared that the value of the sludge holding capacity was higher than those of the RESMAS and FAST processes, and the periods of the critical operating time were proportional to the substrate hydraulic loadings.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.103-114
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• 2017

A membrane bioreactor by sequentially alternating the inflow and by applying a two-stage coagulation control based on pre-coagulation was evaluated in terms of phosphorus removal efficiency and cost-savings. The MBR consisted of two identical alternative reaction tanks, followed by aerobic, anoxic and membrane tanks, where the wastewater and the internal return sludge alternatively flowed into each alternative reaction tank at every 2 hours. In the batch-operated alternative reaction tank, the initial concentration of nitrate rapidly decreased from 2.3 to 0.4 mg/L for only 20 minutes after stopping the inflow, followed by substantial release of phosphorus up to 4 mg/L under anaerobic condition. Jar test showed that the minimum alum doses to reduce the initial $PO_4$-P below 0.2 mg/L were 2 and 9 mol-Al/mol-P in the wastewater and the activated sludge from the membrane tank, respectively. It implies that a pre-coagulation in influent is more cost-efficient for phosphorus removal than the coagulation in the bioreactor. On the result of NUR test, there were little difference in terms of denitrification rate and contents of readily biodegradable COD between raw wastewater and pre-coagulated wastewater. When adding alum into the aerobic tank, alum doses above 26 mg/L as $Al_2O_3$ caused inhibitory effects on ammonia oxidation. Using the two-stage coagulation control based on pre-coagulation, the P concentration in the MBR effluent was kept below 0.2 mg/L with the alum of 2.7 mg/L as $Al_2O_3$, which was much lower than 5.1~7.4 mg/L as $Al_2O_3$ required for typical wastewater treatment plants. During the long-term operation of MBR, there was no change of the TMP increase rate before and after alum addition.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.949-956
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• 2010

A method for simultaneous removal of nitrogen and phosphate from sewage by elemental sulfur denitrification with membrane bioreactor was proposed, and capacity $10\;m^3$/day of pilot plant was operated for 350 days. This study was investigated to have the effect of denitrification rate and T-P removal with the addition of Alum in Sulfur denitrification Reactor (SDR). The addition of Alum and alkalinity ($NaHCO_3$) in the effluent of MBR was tried to remove simultaneous phosphate and nitrogen in SDR. Characteristics of total nitrogen (T-N) and total phosphate (T-P) removal was compared without and with the addition of Alum as a coagulant. T-N removal without and with the addition of Alum was 92.1% and 87.8%, respectively. And denitrification efficiency was 93.8% and 87.1%, respectively. T-P removal rate was increased to 75.6% in SDR by addition of Alum (2.6~4 mg/L as Al), but T-P removal rate was about 26.7% without the addition of Alum. Therefore, denitrification rate was 6.7% of reduction but T-P removal rate was increased by addition of Alum.