Water Reuse for Cooling Tower in Water Shortage Area

Abstract

The water is the limited resources in Kalasin, while the replacement and new power plants need to be constructed for ensuring stability of power supply in upper northeast of Thailand. This is the challenge reserving and suppling power generation in water scarcity area.  Electricity Generating Authority of Thailand (EGAT) seriously concerns about the limited resources in water shortage area. Thus, water reuse and water recycle are the key for sustain water in scarcity province and resolving water pollution for the large scale.

This study focuses primarily on the sustainable water resources design of the treatment system of make-up water from domestic waste water for the power plant’s cooling water. The volume of wastewater was calculated by MIKE Urban 2017 with Ecolab. Recycled water for cooling tower can reduce water replacement of make-up water, but the level of nutrient of water will increase. The important parameters in cooling system are algae, bacteria and other chemicals (chloride, calcium, silica, total hardness). The process of treatment and production for cooling water comprises of coagulation-flocculation, sedimentation, ultrafiltration (UF), and nanofiltration (NF) or reverse osmosis (RO) for chemical control, while chlorine, ozonation and ultrasonic are alternative processes controlling of microorganism in cooling system.

The 78.6 million m³/year treated municipal wastewater in Kalasin is divided into 47.8 million m³/year of makeup water process and 30.8 million m³/year for ecology system preservation. For make-up water system, the proposed treatment processes can save approximately 10.1 to 19.2 percent of cooling tower make-up water by using up to 7 cycles of concentration.