OCR Text |
Show installations, whether they are for new construction, replacement or retrofit. Provisions may include: o Prohibit the installation of all new flow- through type systems or all new flow- through systems with a capacity greater than a stated minimum. ° Require the installation of recycling equipment and/ or provisions for reuse on all new cooling equipment. o Require new recycling equipment to meet standards for minimum water conservation ( cycles of concentration) and maximum pollutant loading ( i. e. maximum TDS limits) for blow down. ° Prohibit the discharge of unpolluted water to the wastewater collection system. ° Require the implementation of cooling water conservation measures by a given date. A prohibition of flow- through type systems would effectively eliminate the use of such water wasting devices. However, there are specific applications where conversion to other types of cooling systems could prove to be difficult if not impossible. Such a prohibition should be accompanied by a provision allowing exceptions following a qualified review process. A standard requiring the installation of recycling or reuse equipment would have an effect similar to a prohibition of flow- through systems. Depending on the regulatory or governing body having responsibility for enforcement, a standard may be easier to implement than a prohibition. Where reuse is proposed as a means of water conservation, plans should be carefully reviewed to insure that a true water savings is obtained, not simply a new means of disposal. If a standard is adopted, requiring the installation of recycling equipment, it should be accompanied by further requirements for process efficiency and waste loading. This will maximize the water conservation benefit while minimizing the impacts to the wastewater stream. A minimum of three cycles of concentration is suggested as a reasonable limit. A maximum of TDS concentration limit of 1500 mg/ 1 is suggested for cooling tower blow down. A prohibition of unpolluted water discharge to the wastewater system may accelerate the elimination of some existing flow though systems still in operation. It may also help to minimize the amount of wastewater treatment: On the other hand, some installations may simply choose to dispose of the water in another manner such as a drainage field or sump, circumventing the intended result of water conservation. The adoption of any of the mentioned prohibitions and standards may result in the conversion from once- through cooling systems to water conserving systems. The full conversion process may not be completed, however, for 10 to 20 years as the useful life of existing units ends and the units are replaced. Opposition to provisions and standards is not expected to be significant, especially if conversion of existing installations is allowed to proceed naturally or within a time frame which does, not place undue financial hardships on facility owners. Resistance may be minimized by the implementation of an incentive program. Such a program might offer rebates to help offset the capital costs, since recycling systems are generally more expensive than once- through systems. The rebates could be further restricted to replacement installations where the time period to pay back from reduced operation and maintenance costs proves to be greater than about five years. Pay- back periods for replacement installations are typically two to three years. * 77 |