• Energy Research

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies, 11, 13, 11A13E: 1-6

The relatively low temperature of thermal discharges from steam-electric power plants makes waste-heat utilization difficult without modification of the power cycle and attendant reduction in electrical energy generated. In situ beneficial use of waste heat by direct once-through condenser discharge into a municipal water supply is discussed. Computations are presented regarding the matching of flow rates, heat losses in distribution and energy savings. A number of benefits and penalties are also assessed qualitatively including legal and operational aspects and reliability. Especially attractive are improvements in electrical generating efficiency, and savings in water-heater energy. Secondary advantages include alleviation of pipe freeze up in winter and improved efficiency of slightly heated waste-water treatment. Penalties include additional pumping power for distribution in the water supply due to increased back pressure on the steam turbines which employ condensers cooled by the water they pump. Additional chlorine is also required to maintain a residual concentration in the distribution system. There may also be difficulties with public acceptance of water preheated by up to about 24/sup 0/F, especially in summer. The water supply of greater Chicago and 4880 MW(e) of colocated fossil-fired load-following generating capacity were analyzed as a hypothetical test case. It was concluded that the net annual energy savings is 23 x 10/sup 12/B, equivalent to 4 million bbl of oil, with a net savings in cost of $12./capita for the population of 4.66 m. While not developed for energy conservation purposes, three actual systems with operating experience are summarized. In order to determine feasibility of application, site-specific systems analysis is required.

A number of wastewater treatment processes were analyzed for possible benefit in using waste heat from co-located steam-electric power plants. Three levels of treatment standards were considered, ranging from secondary treatment to stricter tertiary requirements which involve nutrient removal. Three sizes of treatment plants were analyzed, ranging from those serving 33,000 to 2,000,000 population. The processes analyzed included activated sludge, trickling filter, rotating biological contactors and the Bardenpho process. In the study, a fraction of the condenser discharge was considered mixed with primary-treated wastewater, thereby accelerating the biological secondary-treatment processes at the expense of dilution. In each case, the most cost-effective fraction of condenser flow to be utilized was determined. After treatment, a portion of the mixture would be returned to the power plant in order to recycle the corresponding condenser discharge and provide the necessary evaporative makeup for the cooling system. The balance of the mixture would constitute the water product of the treatment plant. The benefit of waste heat used to replace fuel oil in sludge digesters was also analyzed. In the case of the lowest effluent standards (Group 1), the most cost-effective secondary treatment process was activated sludge without waste-heat recycle because it is dominated by non-thermalmore » considerations. Group 2 standards were favored by rotating biological contactors with waste-heat recycle. The most advanced Group 3 standards were optimally met by the Bardenpho process, also with waste-heat recycle. In all cases, anaerobic sludge digestion with waste heat in place of fuel oil was most economical. The overall savings in levelized annual costs ranged from 1.5% for the smallest plants to 9.9% for the largest plants, by using waste heat optimally as compared with optimal systems without waste heat.« less

In this paper the authors present a simplified thertmodynamic model able to predict the operating conditions of a waste-to-energy plant. Unlike simplified models typically used to monitor a plant operation, the porposed model does not employ correlations based on empiric observations or on experimental data regressions. The developed numerical tool, being phenomenological, is generally applicable to any waste-to energy plant, and is here applied to HERAmbiente S.p.A. plant in Pozzilli, Italy. Input parameters are determined from measurements and the obtained results are validated against experiments, showing a good agreement. The model allows verifying the constraints imposed by the European legislation on temperature and residence time of the combustion products in the plant chamber.

A separate abstract was prepared for each of the 13 papers presented at the conference.

The report discusses the actual implementation of the best alternative in selling electrical power generated by an existing waste-to-energy facility, the Metro-Dade County Resources Recovery Plant. After the plant processes and extracts various products out of the municipal solid waste, it burns it to produce electrical power. The price for buying power to satisfy the internal needs of our Resources Recovery Facility (RRF) is substantially higher than the power price for selling electricity to any other entity. Therefore, without any further analysis, it was decided to first satisfy those internal needs and then export the excess power. Various alternatives were thoroughly explored as to what to do with the excess power. Selling power to the power utilities or utilizing the power in other facilities were the primary options.

This bibliography is an updated version of Municipal Solid Waste Management: A Bibliography of US Department of Energy Contractor Reports Through 1994 (NREL/TP-430-7886). The original bibliography, entitled Municipal Waste to Energy: An Annotated Bibliography of US Department of Energy Contractor Reports, by Caroline Brooks, was published in 1987. Like its predecessor, this bibliography provides information about technical reports on energy from municipal waste that were prepared under grants or contracts from the US Department of Energy. The reports listed focus on energy from municipal waste technologies and energy conservation in wastewater treatment. The bibliography contains three indexes--an author index, a subject index, and a title index. The reports are listed alphabetically in the subject areas and may appear under more than one subject. All of the reports cited in the original MSW bibliography are also included in this update.

The technical and economic feasibilty are examined of the ANFLOW process, an anaerobic process for removing suspended solids and oxygen-demanding organics from waste water by forcing the waste to flow upward through a column that contains a solid packing material supporting microorganisms. Bovine ruminant fluids are used to innoculate the columns with anaerobic microbes. The equipment and test procedures are described. These studies showed that the ANFLOW process meets standards for the secondary treatment of most municipal wastewaters with much less energy consumption (less than half) than activated sludge systems; methane is produced in this process but is expensive to recover; for plants with design flows of l mgd or less, ANFLOW systems appear to cost less than conventional systems; and the applicability of ANFLOW systems to large plant design flow must await future large-scale testing results. It was concluded that the ANFLOW process as compred with existing wastewater treatment systems is simple in design and operation, requires less land area, and conserves energy. (LCL)

By analyzing the world's best practices, the mining waste dumps can be turned into suitable land for location the renewable and clean energy power plants. There are several advantages that characterize these locations: they are characterized by the environmental conditions that are not acceptable for commercial or residential development. Generally, they are located near the existing roads and energy transmission or distribution infrastructure. They can be adequately zoned for renewable energy sources, provide the opportunity for employment in the urban communities and to promote cleaner and more cost-effective energy technologies, reduce the impact of energy systems on the environment (e.g. reduce the emission of harmful gases). As the solar power plants are usually built on large areas, which can lead to the changes in geological and geotechnical conditions along the project site, it is extremely important to design the appropriate geotechnical investigations to reduce or limit the geological uncertainty and determine the suitability of site for construction. In these cases, the geotechnical studies are very complex, striving for a multidisciplinary approach in analyzing the site in question for construction a solar power plant, respecting the current legislation , regulations, norms and standards.

Obstacles currently facing the solid waste recycling industry are often related to lack of public and investor confidence, issues of profitability and liability, and insufficient consumer identification with products made from recycled materials. Resolution of these issues may not be possible without major changes in the way the solid waste recycling business is structured. One potential solution takes the form of the secondary resource utilization park. The premise is simple: Provide a strategically located facility where a broad range of secondary resources are separated, refined or converted, and made into new products on the site. The secondary material resources would come from municipal solid waste, demolition waste, landscape trimmings, used tires, scrap metal, agricultural waste, food processing waste, and other non-hazardous forms. The park would consist of separation and conversion facilities, research and product standards laboratories, and industries that convert the materials into products and fuels. Energy conversion systems using some waste streams as fuel could be located at the park to supplement energy demands of the industrial operations. The strategic co-location of the resource providers and user industries would also minimize transportation costs and could provide a test case for an industrial ecology'' approach to sustainable economic development.