일반적으로 SWRO의 경우 에너지 소비량은 3.5 kWh/m³ 이상의 에너지를 소비한다. 그중 RO트레인은 2.5～3.0 kWh/m³를 소모해 전체 에너지 소비량의 70% 이상을 소비하고 있으며, 전체 시스템 에너지 절감을 위해서는 RO트레인의 최적 설계가 중요하다. 따라서 당사는 다양한 RO트레인의 설계를 최적화 하여 소모되는 에너지의 양을 10% 절감하고자 한다. 1) ISDInternally Staged Desing)을 적용한 1st Pass의 설계최적화, 2) SPSP(Split Partial Sencond Pass) 적용을 통한 2nd 용량 최적화 설계, 3) 초고성능 막을 적용한 Single Pass 설계방법의 최적 조합을 통해 저에너지 역삼투막 시스템 설계 기술을 개발하고자 한다.

According to the nuclear safety act, the enforcement regulations and the notification of the atomic energy commission, a preliminary decommissioning plan must be submitted at all domestic nuclear facilities. In accordance with this preliminary decommissioning plan, it is required to prepare eleven items from the outline of the decommissioning plan of the nuclear facility to the fire protection. Currently, the nuclear fuel cycle facility operated by the Korea Atomic Energy Research Institute (KAERI) consists of a radioactive waste form test facility (RWFTF), a post irradiation examination facility (PIEF), a radioactive waste treatment facility (RWTF), and a radioactive waste storage facility (RWSF). The decommissioning strategies, decommissioning methods and dismantling activities of these nuclear facilities are described in this paper. The scope of decommissioning, the dismantling method, the final conditions of the site, the management of radioactive waste, and the cost of decommissioning are established in the decommissioning strategy. The decommissioning schedule, work order, basic principle and technical feasibility are determined at the method of decommissioning. The disinfection techniques and activity plans for facilities and sites contaminated with radioactive materials are described at the dismantling activity. Therefore, this paper describes the concept of decommissioning of the nuclear fuel cycle facilities and prepares a preliminary decommissioning plan to be prepared afterwards.

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 PO4-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 Al2O3 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 Al2O3, which was much lower than 5.1∼7.4 mg/L as Al2O3 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.

Capacitive deionization(CDI) has many advantages over other desalination technologies due to its low energy consumption, less environmental pollution and relative low fouling potential. The objectives of this study are evaluate the performance of CDI which can be used for dissolved salts removal from sewage. To identify ion selectivity of nitrate and phosphate in multi-ionic solutions and adsorption/desorption performance related to applied potential, a series of laboratory scale experiments were conducted using a CDI unit cell with activated carbon electrodes. The CDI process was able to achieve more than 75 % TDS and NO3-, NH4+ removals, while phosphate removal was 60.8 % and is inversely related in initial TDS and H3- concentration. In continuous operation, increasing the inner cell pressure and reduction of TDS removal ability were investigated which are caused by inorganic scaling and biofouling. However a relative mild cleaning solution(5 % of citric acid for calcium scaling and 500 mg/L of NaOCl for organic fouling) restored the electrochemical adsorption capacity of the CDI unit to its initial level.