Metal contaminants, soils/sludges

This is an ex situ anaerobic bioremediation technology for metal-contaminated soils, sludges, and sediments. While metals are the primary pollutant treated, the biological system also degrades and removes organics such as hydrocarbons. 

Flie/Jbach, A. Martens, R. Reber, H.H. Soil microbial biomass and microbial activity in soils treated with heavy metal contaminated sewage sludge. Soil Biol. Biochem. 1994, 26, 1201-1205. 

The heap leaching process can be used to treat contaminated soil, sludge, or solid waste. The process treats large volumes of low-concentration waste, recovering metal for recycling. The process can be used in conjunction with other processes to treat organic contaminants and can also be used as postbiological treatment. 

Wild, S.R., Obbard, J. P., Munn, C. I., Berrow, M.L. Jones, K.C. (1991b). The long-term persistence of polynuclear aromatic hydrocarbons (PAHs) in an agricultural soil amended with metal-contaminated sewage sludges. Science of the Total Environment, 101, 235-53. 

Burridge, J.C. and Berrow, M.L.B. (1984) Long-term effects of metal-contaminated sewage sludges on soils and crops. In Proceedings of the International Conference on Environmental Contamination, London, CEP Consultants, Edinburgh, pp. 215-224. 

In China and other countries, the application of C-rich organic materials to heavy metal-contaminated soils is a common practice. However, the potential risk of metal mobilization should not be overlooked when metal dissolution facilitated by DOM released from organic wastes exceeds metal immobilization caused by particular organic matter. Figure 10.8 demonstrates that addition of DOM derived from green manure, pig manure, peat, rice litter, and sewage sludge to a Cu-contaminated soil caused an increase in soil water-soluble Cu contents. Compared to the control (no... 

Elevated copper and zinc concentrations in soil adversely affect microbial biomass, activity, and composition of microbial communities in soil adjacent to copper smelters and copper-tailings dumps. 3,4 Nitrogen fixation was adversely impacted when heavy metal-contaminated sewage sludge was added to soils. 5 ... 

Obbard JP, Jones KC. Measurement of symbiotic nitrogen-fixation in leguminous host-plants grown in heavy metal-contaminated soils amended with sewage sludge. Environ Pollut 2001 111 (2) 311-20. 

Obbard, J., Sauerbeck, D., and Jones, K. (1993). Rhizobium leguminosarum biovar. trifolii in soils amended with heavy metal contaminated sewage sludges. Soil Biol. Biochem. 2S, 227-231. 

An environmental application of liquid extraction is the removal of trace organics from water. Examples are the separation of acetic acid-water mixtures and removal of solvents, insecticides, pesticides, etc., from water. It can also be applied to the separation of liquids with close boiling points or those that form azeotropes, such that distillation is not useful. In addition, zero- or low-volatility compounds, such as metals and organometallic derivatives, can be separated by liquid extraction as can mixtures of water-hydrogen bonded compounds, such as formaldehyde. Solid extraction (leaching) can be used to remove organics or heavy metals from contaminated soils, sludges or contaminated equipment. 

Supercritical CO2 has rapidly been gaining attention as a viable replacement for many traditional organic solvents used for the extraction of metal ions from contaminated soils, sludges, and wastewater streams due to increasing... 

Soil. The first reported field trial of the use of hyperaccumulating plants to remove metals from a soil contaminated by sludge appHcations has been reported (103). The results were positive, but the rates of metal uptake suggest a time scale of decades for complete cleanup. Trials with higher biomass plants, such as B.juncea, are underway at several chromium and lead contaminated sites (88), but data are not yet available. 

DeCaF treats soil, sludges, solids (e.g., slag), residues, and sediments contaminated with radioactive elements and other hazardous constituents. The technology has potential applications in the treatment of heavy metals. The technology can treat uranium-contaminated calcium fluoride matrices, rare-earth ore residues, and fluorspar contaminated with uranium. The technology can also extract more complex fluoride by-products. 

The acid extraction treatment system (AETS) reduces the concentrations and/or leachability of heavy metals in contaminated soils so that the soils can be returned to the original site. The main application of the AETS is to extract heavy metals from soils. Additional applications of the AETS include treatment of contaminated sediments, sludges, and other heavy-metal-containing solids. 

Electrokinetic treatment can be used to remediate soils, sludges, and sediments contaminated with heavy metals and organic hydrocarbons. Electrokinetic treatment works well on clay-type soils with low hydraulic permeability, which are difficult to treat using other in sitn technologies. Electrokinetic permeabilities for aqueous systems in clays have been demonstrated to be up to 1000 times greater than normal hydraulic permeabilities, and some heavy metals have exhibited removal efficiencies of up to 100%. 

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