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Use Of A Bench-Scale Treatability Study To Determine Cost-Effective Disposal Methods For Contaminated Sediments
Cost-effective disposal is a major concern for sediment remediation projects that require removal of sediments. To meet landfill criteria sediments must pass tests for hazardous waste content, hazardous waste leachability and residual moisture content. A knowledge of these parameters is essential before the cost of the remediation can be estimated. CRA has developed a laboratory treatability study procedure to obtain the required information rapidly. An example of the application of this procedure is a treatability study that was conducted on heavy metal contaminated dredged sediment from a site in Michigan Three sediment samples were obtained and composited to form a sample that would be representative of site conditions. To be acceptable for disposal at a non-hazardous waste landfill the sediment samples must pass TCLP, stability criteria, and the paint filter test. Sediment leachate data showed that the sediment met only TCLP criteria, therefore stabilization was necessary. Ten polymers were evaluated for their effect on solids settling. A sediment slurry was settled with and without polymer treatment and the supernatant and settled solids were collected. A filter press was used to dewater the settled solids to produce a filter cake, which was tested for water content, TCLP metals, and the paint filter test. The effects of solidification agents on the settled solids were also evaluated. The agents tested were Portland cement, fly ash, and cement kiln dust. The results showed that untreated settled solids did not meet landfill stability requirements. The ability of polymer treatment, solidification and filter cake from dewatering using a filter press to meet the landfill stability requirements will be described. Based on the results of the treatability study a cost-effective technique for sediment treatment and disposal was determined
SUCCESS IN RAT CONTROL IN KUWAIT
The preliminary rat survey prior to the actual attack phase of Rat Control Program in Kuwait revealed an infestation rate with the Norway rat, Rattus norveqicus, in buildings ranging between 32.7% and 70.7%. The comparatively high infestation was observed in 92.5% of Kuwait buildings. Moreover the infestation reached 99% in certain districts of the country. This high infestation was associated with an increase in rat-borne diseases particularly murine typhus, salmonellosis, rat-bite fever and certain parasitic diseases. A programme for rodent control in Kuwait was initiated through a political decision by the cabinet which gave the full responsibility of rodent control to the Ministry of Public Health coordinating with other authorities involved in the problem in addition to an independent budget to fulfill all the program requirements. Financing, administration, guidance, public health information, field work, and research studies were all monitored by the High Committee in addition to Supervising and Following up Committee. The first phase of the program began in the late months of 1979. It included geographical reconnaisance, survey of rodents and their ectoparasites, establishment of the general plan, and a skeletal organization for the program. The second phase was the attack phase. It highlighted biological and epidemiological studies, bioassays of pesticides and training of personnel, which was followed by the actual chemical attack of the incriminated rodents and their ectoparasites for three consecutive years. In addition, sanitation and health education were involved. The third phase, i.e., the maintenance phase, began in August 1982. It is still running to maintain the drastic drop of the Norway rat infestation and to control the house mouse. Kuwait\u27s control program, based on a scientific basis and with a well-organized administration, has successfully realized 99.7% reduction in the infestation rate, with a 99.6% density of infestation Of Norway rats remaining at the end of the attack phase. However, the control of the house mouse produced a reduction of only 71.4% in the infestation rate, and 20% in the density of infestation, possibly indicating intraspecific competition between the two species or less-effective control measures against the mice