AN INTRODUCTION TO THE CASCADING WATER MANAGEMENT SYSTEM FOR SUSTAINABLE WATER CONSERVATION AT WASTE-TO-ENERGY FACILITIES

Currently, there are 86 communities in the U.S. which employ waste-to-energy (WTE) facilities as a means of high quality solid waste disposal. The WTE process beneficially produces electricity while reducing the volume of landfill waste by up to 90 percent, thereby extending the remaining life of a community's landfill more than ten-fold. However, the traditional WTE process requires a significant volume of water. This interdependency is often referred to as the "water-energy nexus." An innovative approach was needed to optimize water conservation for a new 3,000-ton-per-day (TPD) mass burn WTE facility in Palm Beach County (PBREF2). With this in mind, a cascading water management system (CWMS) was developed that uses alternative water supply sources and a cascading hierarchy of water systems that maximize reuse to meet the new facility's. water needs. The selection of an air-cooled condenser to be used for cooling purposes; instead of the wet cooling systems traditionally in place at these facilities will also significantly reduce the amount of water needed in the overall process. The WTE facility will be constructed adjacent to an existing 2,000-TPD refuse-derived fuel facility (PBREF1), allowing beneficial reuse of some of the cooling tower blowdown from the RDF facility as a source of supply water in the new facility. The reuse of this process wastewater will conserve clean water sources that otherwise would have to be used as a source of makeup to the new facility, as well as reduce the amount of wastewater disposed through deep-well injection from the RDF facility. Harvested rainwater and industrial supply well water will also be used as alternative sources of supply to the new facility. The innovative CWMS will maximize reuse and reduce the amount of makeup water needed to the system. As water conservation continues to be of high concern in all areas of the globe, this concept can be applied to other WTE and industrial facilities. This paper will provide an overview of the innovative CWMS that has been designed for the PBREF2 facility.