INFORMING THE PROCESS AND OUTCOMES OF RECYCLING IN THE UNITED STATES: THE NATIONAL MUNICIPAL SOLID WASTE RECYCLING SYMPOSIUM Douglas J. Lober Assistant Professor
Abstract The National Municipal Solid Waste Recycling Symposium, held at Duke University's Nicholas School of the Environment August 10th and 11th, 1994, brought together 22 national municipal solid waste (MSW) experts to take a fact-based look at recycling to determine current and future levels of recycling in the United States and to examine key influences on recycling activity. There were several findings. One is that no national legislated or voluntary definition of recycling exits, despite this being crucial for developing waste management policy. The United States is currently recycling 20 percent of the nation's MSW or 42 million tons per year of the 200 million tons of MSW generated. More than two thirds of all recycling tonnage can be classified as being from four waste items: yard trimmings, corrugated boxes, newspapers, and glass containers. The average U.S recycling rate goal by state is 39 percent. Few states are close to reaching these goals. Over the next five years, given current markets and economics and infrastructure capabilities, the symposium consensus was that a national recycling rate of 33 percent to 38 percent is obtainable. Recycling of yard trimmings has the greatest potential to contribute to the increase in recycling. Federal government involvement in recycling is likely to be in data collection, cost accounting, market development, and determining the relationship of recycling relative to other waste management strategies and to other environmental problems such as global warming. These findings are a useful starting point to advance further discussions of municipal solid waste recycling policy. Key Words: Recycling, Municipal solid waste, Waste management, Source Reduction, Environment, Callaboration
A CRITICAL REVIEW OF PHOTOGRAPHIC AND RADIOGRAPHIC SILVER RECYCLING David Eugene Kimbrough
Phillip W. Wong
Jeffrey Biscoe
Joshua Kim
ABSTRACT Much of the silver consumed annually in the United States is used in photographic and radiographic applications. Small operations such as local doctors' and dentists' offices, veterinary clinics, and one hour film developers consume the bulk of this silver during the photographic/radiographic developing process. Once used, the majority of this silver ends up as waste, typically as sediment in our nation's waterways or as solid waste in landfills. Although this silver could easily be recovered and recycled, the current regulatory environment makes disposal an easier, less costly option for these small generators. This paper explores the current laws and regulations that discourage recyling, the technologies available for silver recovery, and options to promote increased silver recycling in the photographic/radiographic area. This paper was originally prepared as material for an academic course. Keywords: Silver, recycling, photographic, wastewater, hazardous waste, policy options
HYDROLYSIS OF NATURAL LIGNOCELLULOSICS, WITH SORBED HEAVY METAL, TO SUGARS BY A BACILLUS SPECIES M. Omanakuttyamma
V.P. Sreedhara
V. Thankamani
ABSTRACT A potent Bacillus species producing the cellulolytic enzymes was isolated from fibre-retting sites along the Kerala backwaters. The organism was identified as a variant of B.subtilis capable of luxurious growth at 60 deg C and tolerating 7g% sodium chloride in the medium. The crude culture filtrate of the organism grown in nutrient broth containing minerals, wheat bran and cellulose was used as the enzyme for hydrolysis experiments. Rubber wood sawdust 60X120 mesh size sorbed heavy metals like copper, lead, chromium, mercury and cobalt in the solution. Pretreatment of the sorbent by boiling and impregnation with ammonium sulfide and sodium sulfide improved sorption by 10-15% (50-60% of the metals was sorbed from solutions of 10 micro gram per ml). Desorption of Co++ from the +sorbent was achieved by treatment with 0.01 M calcium chloride. The sorbent retained 5-6 micro gram of metal ions per gram. Presence of Co++ at this concentration in the saw dust improved hydrolysis of the cellulosic substrate to sugars by the culture filtrate. 6-18 micro gram per ml Co++ in growth medium enhanced exoglucanase secretion by 20-30% and enzyme activity. Sorption of Co++ was closely associated with primary metabolism and biomass build-up. The data point towards the role of cobalt ions in the cellulase stabilization and/or activation. Key Words: Lignocellulosics, Biosorption, Heavy metals, Bacterial cellulases
DETOXIFICATION OF FLY ASHES FROM RDF INCINERATION PLANT Arcangeli L, Cipriani P., Galeotti L, Gavasci R, Sirini P PMP Sez. Dec. Acque Potabili Az. USL RM/A - Rome, Italy
ABSTRACT Incineration has become more and more used for solid waste treatment. This is mostly due to volume reduction and energy recovery. However, the amount of solid residues from incineration process needs treatment systems to reduce the environmental risks due to their high content of heavy metals. This paper presents the results of an experimental work whose purpose is to develop an extraction process to reduce the leachability of heavy metals contained in the fly ashes from Refuse Derived Fuel (RDF) combustion process. This treatment aims at reducing the disposal costs of fly ash by allowing its disposal in landfills at lower environmental risk. Key Words: RDF, Incineration, Fly Ashes, Detoxification, Heavy Metals, Leachability
CONCEPTUAL DESIGN OF THE AUTOMATED COLLECTION/PROCESSING INTERFACE Richard Ian Stessel, Ph. D., P. E.
ABSTRACT Recycling has proven to be far more costly than originally admitted. Two factors interact to raise costs: categories of materials collected and collection technology. Collection costs have always formed a large component of solid waste management. With curbside segregation, each additional material collected adds to collection costs. Even then, material quality is frequently inadequate. Simultaneously, some communities are moving away from curbside segregation to co-mingled or blue-bag collection, which require a MRF. The importance of considering automated collection has already been discussed. This paper presents an updated variant on a concept for an automated collection vehicle. This proposed vehicle employs selective compaction of materials to improve quality. Efficiency is best achieved when the new collection technology and the automated MRF are designed to work together. This paper explores that interface by briefly discussing MRF compatability with the proposed collection vehicle. Key Words: Recycling, Automated Processing, Waste, Collection, Materials Recovery, Resource Recovery
SOLID WASTE RECYCLING, DISPOSAL AND MANAGEMENT
IN BANGKOK
Samorn Muttamara, Candelaria L. Sales and Salaya Phunsiri Environmental Engineering Program
ABSTRACT Solid waste recycling should be integrated with other solid waste management options to abate degradation in urban environment. This can be achieved through promotion of economically efficient and environmentally sound practices in managing municipal waste. Recycling can be promoted by encouraging separation at source. The best way of waste separation at source can be stimulated by financial incentives, legislation and raising of environmental awareness. In Bangkok, 90% of the solid waste is disposed of by open dumping. Around each disposal site, there are a number of small scale recycling shops (SSR) where collected materials are sold by the collection crews and the scavengers. The quantity of materials delivered to each of these SSR shops by the collection crews ranges from 1 to 6 tons per day. The total daily tonnage of recyclable materials collected by waste pickers was estimated at 286.03 tons, about 5% of the garbage collected by the city (TAMS PIRNIE, 1989) and is increased to 9.6% (TSAI CHIN, 1993). Open dumping has been found to create environmental problems because of air pollution, bad smell, presence of insects and rodents which are injurious to health, and potential contamination of ground water. The levels of BOD and SS of the leachate and khlong water in On-Nooch disposal site exceeded the standard value of 20 and 60 mg/L BOD and SS, respectively. Dissolved oxygen was found to be very low, about 0.88 to 1.90 mg/L. Khlong water also contains high Mn content of 0.12 - 1.39 mg/L compared with the standard value of 0.3 mg/L. Furthermore, the existing ambient air quality in On-Nooch revealed that the highest level of methane and carbon dioxide was 13.07 mg/m3 and 1758.33 mg/m3 (8 hr ave.), respectively at night time collected on top of the refuse mountain. These gases may cause explosion or fire if not exhausted properly to air. It is recommended therefore, that open dumping should be converted to a sanitary landfill with proper environmental protection measures in order to minimize environmental pollution. However, it is also proposed that the government, if possible, should adopt the waste-to-energy treatment system since it is not possible by sanitary landfill to eliminate all the negative impacts to the environment. |
