Dorairaja Raghu

Considerations in disposal of phenolic waters

Concentrations of phenol in water as low as 1 mg/L make it unsafe for human use. Thus, the disposal of phenolic waters poses a major problem. In this paper, an actual case study of disposal phenolic waters from a producer gas plant in India is discussed. Several methods for the disposal of phenolic waters were considered. One of the options involved construction of an earthen embankment for storing slag and phenol. This pond will be located near a river. So a concern exists regarding river pollution. Details of this and the other options considered and the cost analyses are presented. All the relevant aspects of the methods to be considered, including the geotechnical, economical, and environment concerns that influenced the decision making process to arrive at a final solution to the problem, are discussed.

Origin, properties and disposal problems of chromium ore residue

Chromium mining operations were conducted in the United States during the first fifty years of this century. During this period, large amounts of chromium waste were produced and used as fill in some areas. Over a period of time, toxic chromium compounds leach out of the ore residue. This poses a severe threat. Structural distress, ground and surface water pollution and parking lot deterioration have been reported in the areas where chromium residue was used as fill. Information regarding chromium residue disposal is rather limited and not readily available. The purpose of this paper is to address this problem and to discuss the production and properties of chromium, and the available technologies for the control and treatment of chromium residue.

Physical characterization of water treatment plant residual and top soil mixtures

Disposal of water treatment plant residuals is not economically feasible due to their high moisture contents, high compressibilities and very low shear strengths. This paper evaluates the physical and geotechnical characteristics of water treatment residual-top soil mixtures for beneficial reuse in construction and land application. Index, compaction, consolidation, strength and durability tests were performed in accordance with the relevant ASTM standards. It was observed that the plasticity of the mixtures decreased and handling (compaction) and other engineering characteristics improved due to the addition of top soil to residuals. There is a potential for these mixtures to be used as liner material for landfills.

Radon contamination in dwellings

Radon contamination of dwellings has only recently been recognized as a significant problem in the United States. This paper describes the geographical distribution of radon gas, along with a discussion of its fundamental health effects. Various methods to measure radon and radon daughter concentration levels are presented. Recommended action levels for radon gas exposure in dwellings are summarized, and factors which influence measured radon concentrations are discussed.