Research of adsorption retardation effect on anti-seepage grouting for landfill site

摘要

In order to develop one kind of slurry with low permeability coefficient and adsorption ability to block the leachate pollutants in landfill site, the orthogonal experiment are used to select optimal formula of the slurry with a bentonite base, which contains: bentonite 20%~24%, cement 16%~24%, fly ash 18%~22%, fiber0.06%~0.12%, soda ash 0.8%~1.2%, diluent FCLS 0.30%~0.75%, and water 680~780ml/1000ml. The material performs good pulp filling ability with a concretion stone ratio larger than 99%, the permeability coefficient of concretion body at 28 day is 0.13×10~(-7)~0.87×10~(-7)cm/s slurry, the compressive strength is 0.75~2.0MPa, and the elasticity modulus is 230~350MPa. The slurry concretion body performs good absorption ability: to NH_4-N and phosphorus at a rates of 98%, to COD_(Cr) and BOD_5 block 85.67%, to Hg, Pb and other heavy meterials 99.91%. Through the infiltration sedimentation and adsorption fixation, the retardation capability of the slurry material is improved to block the pollutants of landfill site leachate.