| Natural water-bearing media contains a large number of colloidal particles.It can carry contaminant and promote or inhibit the migration in water-bearing media.Therefore studying on the migration and transformation law of ammonium nitrogen in the groundwater environment is particularly important.This paper conducts a series of laboratory soil column experiments,the influence of particle size,colloid concentration to colloidal ammonium nitrogen’s migration and retention of natural colloidal ammonium chloride solution and landfill leachate is disscussed,the migration regularity and colloid electric properties of different forms’ ammonium nitrogen under different particle size water-bearing media and colloid concentration of ammonium chloride solution and landfill leachate are studed.The above studys obtain the following innovative understandings and conclusions:(1)Under the particle size of 337μm、189μm、152μm、120μm、80μm,three forms’ammonium Rd by 337μm particle size of 0.74,0.82,0.57 to 80μm particle size of 1.7,1.89,1.8.rd by 337μm particle size of 0.76,0.69,0.76 to 80μm particle size of 1.94,1.61,1.9.With the decrease of the particle size of the water-bearing media,the migration and release speed of natural clay colloid ammonium chloride solution’s total ammonium nitrogen,dissolved ammonium nitrogen and colloidal ammonium nitrogen slow down,penetrate and release time are longer,the accumulation retention volume’s growth rate and maximum cumulative retention volume of colloidal ammonium nitrogen become bigger.Colloid promotes ammonium nitrogen’s migration under larger particle size as 337μm,189μm,small particle size as 152μm,120μm and 80μm has inhibitory effect on the migration of ammonium nitrogen.(2)The potential of test sample water under five particle sizes are negative,after ammonium completely migrated,the mean colloid relative concentrations are:0.934,0.674,0.663,0.409,0.327.With the decrease of particle size,aqueous medium’s ability to block colloid has increased.The greater the colloid concentration,the greater the test water sample colloid relative concentration.The cumulative-retention and cumulative-releasement volume of colloid conform to the linear equation,colloid’s cumulative retention amount is greater than the cumulative release amount,the release of the colloid is not completely.In the migration process,the colloid particle size decreased and the potential increased gradually as pore volume number increased,the regularity of release process is opposite.(3)The cumulative retention volume and cumulative release amount of colloidal ammonium nitrogen fluctuating decreased as pore volume number increased,the retardation on various forms of ammonium nitrogen increased frome low colloid concentration to high.(4)The release process of colloid under different ammonium chloride solution colloid concentrations is in pulsed type,with a trailing phenomenon.Under 8 mg/L,16 mg/L,30 mg/L,60 mg/L,120 mg/L colloid concentrations,after ammonium completely migrated,the mean colloid relative concentrations are:0.589,0.673,0.683,0.673,0.683.The greater the colloid concentration,the greater the test water sample colloid relative concentration.The cumulative-retention and cumulative-releasement volume of colloid conform to the linear equation,colloid’s cumulative retention amount is greater than the cumulative release amount,the release of the colloid is not completely.(5)The migration and release processes of landfill leachate ammonium nitrogen are in S model.Small particle size as 80μm water-bearing media has a better effect on retention of landfill leachate solution colloidal ammonium.The higher the landfill leachate colloid concentration,the greater the retention volume.With the decrease of the particle size and the colloid concentration increases,the largest cumulative retention volume increased.(6)In the entire migration-release process of landfill leachate ammonium nitrogen,all the potential are negative.With the decrease of the water-bearing media particle size,water samples’ colloidal particle size reduced and potential increased.With the increase of landfill leachate colloid concentration,colloidal particle size of water sample increased and the colloidal potential decreased. |
