Soils, reclaiming

Jain, P., Kim, H. and Townsend, T.G. (2005) Heavy metal content in soil reclaimed from a municipal solid waste landfill. Waste Management, 25(1), 25-35. 

Soluble salts—halite (NaCl) and gypsum (CaSC>4 2H2O), as well as sulfides (pyrite, FeS2) in soils reclaimed from seas or swamps. These minerals readily dissolve in percolating water or, in the case of the sulfides, are readily attacked by oxygen. Saline and sodic ( alkali ) soils are examples of this category. 

S application to soil Normal soil Reclaimed soil ... 

Granular base Blast furnace slag Coal boiler slag Mineral processing wastes Municipal solid waste combustor ash Nonferrous slags Reclaimed asphalt pavement Contaminated soils Reclaimed concrete Steel slag Waste glass... 

Cat clay soils can have pH values as low as 3.0. These soils, which are commonly found in Delaware, Florida, New Jersey, and North Carolina, are formed when neutral or basic marine sediments containing FeS2 become acidic upon oxidation of pyrite when exposed to air. For example, soil reclaimed from marshlands and used for citrus groves has developed high acidity detrimental to plant growth. In addition, H2S released by reaction of FeS2 with acid is very toxic to citrus roots. 

Competition of different cations for cation exchange sites on soil cation exchangers may be described semiquantitatively by exchange constants. For example, soil reclaimed from an area flooded with seawater will have most of its cation exchange sites occupied by Na+, and restoration of fertility requires binding of nutrient eations such as K" " ... 

Upon elimination of the fluids, the liner to the pit is folded over the residual solids in a way to prevent fluid migration. The liner is then buried inplace. The operator may choose to remove the liner contents completely to preclude any future contamination. In the case of a producing well, the location is reclaimed up to the deadmen. The adjacent areas are contoured to provide for drainage away from the production facilities. In the case of a dryhole, the entire location is reclaimed to the initial condition. All of the reclaimed area should be ripped to enhance soil conductivity. The top soil is then spread over the reclaimed area followed by seeding. Local seed mixtures are broadcast to quicken reintroduction of native plants. 

Soil structure and land drainage within the reclaimed ground. 

Saline soils vary considerably in their salt content, type of salt, structure and ease to be reclaimed. Dominant anions are chlorides, sulfates and carbonates, sometimes nitrates and bicarbonates. Sodium salts occur most frequently, but calcium and magnesium compounds are common as well, while mixtures of various salts and complex minerals are not exceptional. The non-salt solution contains mainly calcium salts (50-80%) magnesium (15-35%), potassium (2-5%) and sodium (1-5%) make up the remaining cations. In saline soils, however, the percentage of Ca2+ is lower, and the values of K+, Mg2+ and Na+ is higher. 

Nitrite formation may lead to nitrous oxide (N O) emission. An example of such a process under reclaimed efQuent disposal on the land surface is reported by Master et al. (2004). Irrigating a grumosol (<60% clay content) with fresh and reclaimed effluent water, it was found that, under efQuent irrigation, the amount of nitrous oxide emissions was double the amount emitted under freshwater treatment, at 60% w/w. The N O emission from efQuent-freated bulk soil was more than double the amount formed from large aggregates. 

Treated materials are limited to clean soil, treated water, and a recyclable or reclaimable pollutant. 

Reclaim is a passive, in situ technology that uses a hydrophobic porous polymer to attract, adsorb, and concentrate petroleum hydrocarbons and volatile organic compounds (VOCs) from soils and/or groundwater. Reclaim is considered a passive treatment technology because it requires no mechanical equipment remediation consists of placing polymer-filled canisters in recovery wells and allowing the containers to attract and adsorb organic contaminants. Reclaim canisters are then recycled and contaminants recovered for analysis and/or disposal. This polymer extracts contaminants whether they are in liquid phase, vapor phase or dissolved phase in water. 

According to the vendor, Reclaim costs will vary according to site-specific factors. Contaminant concentrations and soil characteristics will have the greatest impact on cost (D140181 DlOlllH). 

It allows the reuse of treated soils in a variety of ways, including backfill at the site of origin, reclaiming aggregate or coal pits, general clean fill, crushed aggregate sales, asphalt mix sales, concrete mix sales, and cover for sanitary landfills. 

Wanner, M. Dunger, W. 2002. Primary immigration and succession of soil organisms on reclaimed opencast coal mining areas in eastern Germany. European Journal of Soil Biology, 38, 137-143. 

Wool is stained less at high temperatures and longer dyeing times because the disperse dye that was initially on the wool component migrates to the PES fiber. Carrier-free dyeable PES fibers should preferably be employed these fibers are easily dyeable even at boiling temperature (see Section 4.12.2). The nature of the wool also plays a role, fine wool and reclaimed wool being more strongly soiled. 

A further area in which sequential extraction continues to be applied successfully is in assessment of the likelihood of mobilisation of metal contaminants from sediment-derived soil. When dredged sediment is used to reclaim land from the coastal margins or applied to arable soil to improve fertility, there is concern that potentially toxic elements accumulated under reducing conditions may be released on exposure to an oxygen-rich environment. Sequential extraction can be used to characterise the sediment prior to application, or to monitor changes in metal availability in the soil with time (e.g. Singh et al, 1998). 

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