Technologies and Costs for Removal of Arsenic From Drinking Water

4.3.3 Dewatered Sludge Land ApplicationDewatered sludge can be disposed by spreading the material over an approved land surface.Application is dependent on several variables, including soil and sludge chemistry and the cropplanted in the application field. Dewatered sludges are typically stored on site until they aretransported for application. Monitoring of soils, run off from land application, and potentially affectedwater sources is advisable to protect open land that may become cropland and to protect local waterquality (DPRA, 1993a).As discussed in the previous section, land application of water treatment residuals containingarsenic up to 41 mg/kg can be land applied without tracking arsenic accumulation. When theconcentration is in the range of 41 to 75 mg/kg, sludges can be land applied if arsenic accumulationis tracked and does not exceed 41 kg As/hectare. Due to the possibility of arsenic absorption byvegetation, application of sludges to non-food chain fields is preferred. Land application is alsolimited by the availability of land. In areas where grassland, farmland, or forested land isunavailable, transportation costs can significantly affect the overall cost effectiveness of this disposaloption.Land application can serve as a means of final disposal of LS, and to a lesser degree C/F,sludges. Lime sludges can have a beneficial impact on farmland by neutralizing soil pH, replacingthe use of commercial products. Alum sludges offer no benefit to soil chemistry and are generallyused as fill material.4.3.4 Sanitary Landfill DisposalTwo forms of sanitary landfill are commonly used for disposal of water treatment byproducts:monofills and commercial nonhazardous waste landfills (DPRA, 1993a). Monofills only accept onetype of waste, for example, fly ash or water treatment sludges. Commercial nonhazardous wastelandfills accept a variety of commercial and industrial wastes.Sanitary landfills are regulated by both state and federal regulations. States have guidelinesgoverning the types of wastes that can be landfilled, and determine construction and operation criteria.In many cases, state requirements are more stringent than the federal regulations promulgated underthe Resource Conservation and Recovery Act (RCRA). Federal requirements include restrictions onlocation, operation and design criteria, groundwater monitoring requirements, corrective actionrequirements, closure and post-closure requirements, and financial assurance.4-9