Earticle

Recently, the importance of the phosphorus management has been increased according to the enforcement regulation issued on 2 April, 2010 by the Ministry of Environment, Korea. Various methods for phosphorus removal have several problems such as high costs for sludge disposal and chemicals. The purpose of this study is to reduce the amount of sludges and cost of chemicals using crystal obtained from phosphorus crystallization in seawater reverse osmosis (SWRO) system. Crystal from pre-crystallization for multi-stage SWRO system was used as seeding substance for ortho-phosphate ions. Ca2+ is the main seeding material, and sufficient concentration could be obtained from the precrystallization step in desalination process. The result showed over 90% removal efficiency and satisfied the effluent water quality standards of 0.2mg T-P/L. Therefore, it is expected to maximize the economic efficiency not only by to use the industrial waste instead of the chemicals, but also to reduce sludge treatment cost.

경제발전에 따른 에너지 소비량 증가로 발전소 건설이 날로 증가추세에 있다. 화력발전소는 연료 수급과 냉각수 공급 을 용이하게 하기 위해 바다나 강가 인근에 건설하는 것이 일반적이다. 주변에 담수 공급이 불가능할 때 해수담수화설비 를 자체적으로 설치하여 발전소에 필요한 용수를 공급한다. 본 연구는 페루 칠카 지역에 설치한 발전소용 해수담수화설 비의 사례를 통하여 해수담수화설비로부터 순수 생산에 이르는 각 설비의 최적 설계 방안과 운전 결과를 고찰하여 향후 유사 지역 해수담수화 설비 설계 시 도움을 주고자 한다. 본 연구의 SWRO 설비는 유입 Conductivity 34-40 mS/cm를 처 리 수질 250-340 micro S/cm로 처리하여 99.3%의 염 제거율을 보였다. 회수율은 52.8-54.6%이며, 운전압력은 58-63 bar 이고 운전 차압은 1.4-2.2 bar 수준이었다.

The construction of power plants is increasing against the high demand of energy consumption due to economic development. In the case of thermal power plants, it is common to build near the sea or river to facilitate fuel supply and cooling water supply. If it is impossible to supply fresh water from the surrounding area, seawater desalination plant shall be built to supply necessary water for the power plant. The purpose of this study is to help the design of the seawater desalination plants at the similar area through reviewing of optimal design method and operation results of each facility from seawater desalination plant to demineralization system based on the case of desalination plant for power plant installed in Chilca, Peru. The treated water quality of SWRO facility was 250-340 micro S/cm from inlet conductivity 34-40 mS/cm, which showed 99.3% salt rejection. The recovery rate was 52.8-54.6%, the operating pressure was 58~63 bar and the operating differential pressure was 1.4~2.2 bar.

Exploitation of sustainable and environment-friendly energy resources is highly required to resolve energy shortage. Recently, salinity gradient power (SGP) is considered as a feasible candidate with high potential to substitute fossil fuels due to its benefits: less periodic, abundance, and no emission of carbon dioxide. In this presentation, SGP processes such as pressure retarded osmosis (PRO) Reversed Electrodialysis (RED), and Capacity Mixing (CapMix) were reviewed with its mechanism, limitations, and available applications. For instance, in a PRO system, water permeates through semi-permeable membrane from feed solution to draw solution, and energy is generated by depressurizing the permeated flow through hydro turbine. Models for understanding of its mechanism and for improving of its performance were overviewed. In addition, applications of seawater reverse osmosis (SWRO), wastewater treatment (WWT), and PRO hybrid process were introduced to develop new water-energy nexus processes. The SWRO-PRO hybrid process and SWRO-PRO-WWP hybrid process can contribute on opening an insight to reduce the total energy consumption in SWRO plant as well as to apply the SGP energy to other engineering fields.