Interaction Between Sludge Solidified With Soda Residue As A Landfill Temporary Cover And Solid Waste Or Leachate

The output of municipal solid waste is increasing year by year,which is a serious threat to human production and life,and the problem of waste disposal is becoming increasingly serious.Sanitary landfill is one of the main methods of waste disposal.Bioreactor landfill developed on the basis of ordinary sanitary landfill can effectively accelerate the degradation of waste.Among them,the temporary cover plays an important role in the bioreactor,which has an important impact on solid waste degradation and leachate composition and concentration.Soda residue is a kind of industrial waste discharged in the process of ammonia soda production,which contains high sodanity and is difficult to treat in soda industry;domestic sludge is a solid substance produced in the process of domestic sewage treatment;soda residue solidified sludge can be used as a temporary covering material of bioreactor landfill to meet the strength and permeability requirements of temporary covering material,but it is different from the solid and liquid of landfill The law of interaction between them remains to be studied.In this paper,two kinds of soda residue solidified sludge were selected as the temporary covering material to study the interaction law and mechanism between soda residue solidified sludge and landfill solid waste and leachate(1)Static adsorption tests were conducted with two ratios of solidified sludge of soda residue as adsorbent.It was found that the adsorption effect of soda slag cured sludge on chemical oxygen demand and ammonia nitrogen in leachate was affected by the adsorption time,solution p H,adsorbent dosage,solution concentration and adsorbent ratio.(2)The p H,COD and ammonia nitrogen concentrations of landfill leachate were monitored over time in a small-scale model experiment using soda residue solidified sludge as a temporary cover layer for bioreactor landfills.It was found that soda sludge solidified sludge used as landfill cover can provide nutrients to the interior of the landfill,help accelerate the hydrolysis of organic matter,and effectively regulate the p H inside the landfill to maintain environmental stability.(3)Based on small-scale model tests,the changes of volatile solids content and biodegradability of landfill solid waste over time were examined.It was found that the use of soda residue solidified sludge as temporary cover material could accelerate the degradation of solid waste to a certain extent.(4)Based on the small-size model test,a micro penetrometer was used to measure the change of penetration resistance or strength of the temporary cover layer with time.It was found that the leachate recharge had a certain corrosive effect on the temporary cover material,which reduced the penetration resistance after long-term operation;the changes of quasi-aerobic or anaerobic operation mode and cover material thickness had little effect on the penetration resistance;increasing the content of slag and quicklime helped to improve the penetration resistance.