SWAG agenda 042215 - Laserfiche WebLink

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0 7 5.3.2 Water Mass -burn and RDF incineration technologies and any WTE that produces steam will require a water supply, and all types of projects have a wastewater discharge. Water is required for the boilers, and domestic water for workers is also needed. Non - potable water may be used as cooling water for the steam condensers, but the large cooling water supplies necessary for condenser cooling are normally not available, and cooling towers or cooling water ponds are provided as part of the facility. Air - cooled condensers are an option, but they increase capital costs and reduce net power production. If the energy is going to a steam customer, the water requirement may be increased significantly from that needed for electricity generation, assuming that the customer generally does not return condensate. Some projects may cogenerate steam and electricity for sale, such as district heating /cooling projects or those with a significant steam user in proximity of the WTE facility site. Technologies such as gasification and anaerobic digestion will not necessarily use a boiler. They may generate a gas stream for use off -site and not require a condenser cooling water system. They may utilize the gas to power a turbine or piston engine. These approaches are not inherent water users; however, gasification systems may require water in the gas cleanup and processing. Each system would need individual evaluation. Biologic systems, including ethanol production and anaerobic digestion, are wet processes. The question to be examined is how much water is required and how much is recycled. The answers to these questions will be system- specific. For example, Arrow -Bio, which uses a water -based system, claims that no water is required for the process other than that in the waste, which is recycled. GBB/C08027 -01 29 August 15, 2008