title: Alkaline solution neutralization capacity of soil.
abstract: Alkaline eluate from municipal solid waste (MSW) incineration residue deposited in landfill alkalizes waste and soil layers. From the viewpoint of accelerating stability and preventing heavy metal elution, pH of the landfill layer (waste and daily cover soil) should be controlled. On the other hand, pH of leachate from existing MSW landfill sites is usually approximately neutral. One of the reasons is that daily cover soil can neutralize alkaline solution containing Ca(2+) as cation. However, in landfill layer where various types of wastes and reactions should be taken into consideration, the ability to neutralize alkaline solutions other than Ca(OH)(2) by soil should be evaluated. In this study, the neutralization capacities of various types of soils were measured using Ca(OH)(2) and NaOH solutions. Each soil used in this study showed approximately the same capacity to neutralize both alkaline solutions of Ca(OH)(2) and NaOH. The cation exchange capacity was less than 30% of the maximum alkali neutralization capacity obtained by the titration test. The mechanism of neutralization by the pH-dependent charge can explain the same neutralization capacities of the soils. Although further investigation on the neutralization capacity of the soils for alkaline substances other than NaOH is required, daily cover soil could serve as a buffer zone for alkaline leachates containing Ca(OH)(2) or other alkaline substances.
authors.affiliation: Fukken Co., Ltd., 2-10-11 Hikarimachi, Higashi-ku, Hiroshima 732-0052, Japan. asakura_hiroshi@yahoo.co.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Asakura
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sakanakura
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Matsuto
mesh_terms: D002118:Calcium / Q000378:metabolism; D002126:Calcium Hydroxide; D006863:Hydrogen-Ion Concentration; D017745:Incineration; D007564:Japan; D008956:Models, Chemical; D012037:Refuse Disposal / Q000379:methods*; D012972:Sodium Hydroxide; D012987:Soil / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D012987:Soil; D014874:Water Pollutants, Chemical; D012972:Sodium Hydroxide; D002126:Calcium Hydroxide; D002118:Calcium