| Now sediments controlled in eutrophic water pollution has been concerned at home and abroad, and the zeolite coverage for a more effective measures, but its service life is subject to certain restrictions. Therefore, the best method of ammonia nitrogen in this study which based on the synthesis of zeolite modified ammonia removal efficiency and in situ biological regeneration rate increased. The effect of ammonium adsorption of zeolite to explore different adsorption biological regeneration effect and biozeolite hanging style changes in the zeolite in situ biological regeneration. Finally, using the in situ cover sediment method to achieve the reduction of river sediment nitrogen pollution load.1. The zeolite was roasting, acid and salt change test shows: Through NaCl modified(per gram of natural zeolite into 10 ml, 1 mol/L NaCl solution, oscillation 24h) of zeolite is the effect of effective modification method of the zeolite in situ biological regeneration, which ammonia adsorption amount compared with natural zeolite improving 1.34 times, in situ biological regeneration rate increased 1.19 times.2. Simulation of the sustained release of ammonia from sediment of 16 d after 83 d, 67 d amounting to zeolite adsorbed 1mg/g, 4mg/g and 5mg/g ammonia nitrogen, operating 30 d after adding different concentration of bacteria bacterial suspension conditions results showing that:(1) the zeolite of ammonia adsorption capacity smaller, the bacterial concentration higher the bacterial suspension regeneration time is shorter. When the concentration of bacteria suspension is 80mL/g, the biological regeneration time of natural zeolite is 42 d, 90 d and 103d; while the modified zeolite is 36 d, 78 d and 84 d. It is showed that ammonium adsorbed zeolite has a certain degree of in-situ regeneration in the remediation of the sediments.(2) The in situ biological regeneration rate of ammonium adsorbed zeolite was faster than before 7d, the natural zeolite was 40.9mg/(kg·d), 108.3mg/(kg·d) and 97mg/(kg·d), while the modified zeolite was 42.5mg/(kg·d), 123.2mg/(kg·d) and 138.3mg/(kg·d), and then as time passes gradually reduce the trend to the next 15~30d period, natural zeolite as 30.1mg/(kg·d), 31.9mg/(kg·d) and 46.6mg/(kg·d), the modified zeolite as 50.1mg/(kg·d), 37.1mg/(kg·d) and 54.4mg/(kg·d).3. The biozeolite in situ biological regeneration test was zeolite in 7d test period adsorbed amount of ammonia:(1) In the low adsorption conditions, the amount of biozeolite regeneration in situ biological rate was increased with increasing amount of the ammonia nitrogen adsorption capacity. The separately hanging biomembrane of natural zeolite’s adsorption capacity as 2.18mg/g reached 47.8mg/(kg·d); while the mixed hanging biomembrane of modified zeolite’s adsorption capacity as 2.39mg/g reached 85.4mg/(kg·d). After with ammonia nitrogen adsorption capacity increased, the biozeolite’s biological regeneration effect will be by inhibition.(2) When the zeolite’s ammonia nitrogen adsorption in less than of 4 mg/g, the separately hanging biomembrane of natural zeolite’s effect is good, the in situ biological regeneration rate as 30~50mg/(kg·d); while the mixed hanging biomembrane of modified zeolite’s effect is good, the in situ biological regeneration rate as 65~85mg/(kg·d). The in situ biological regeneration rate of biozeolite and sediment ammonia nitrogen average release rate(average ammonia release rate 60~70mg/(m2·d), zeolite sediment density for 1kg/m2) equal to that of biozeolite can be sustained and remediation of contaminated sediments.4. A zeolite layer remediation sediment experiments show that:(1) Under the confined conditions, the overlying water total nitrogen removal rate of coverage natural zeolite, modified zeolite, natural biozeolite and modified biozeolite system reached 60.72%, 69.39%, 75.52%, 82.41% respectively.(2) Under the simulation of rivers and lakes, after three rounds of sediment cover test, which cover the mixed hanging biomembrane of natural zeolite overlying water total nitrogen abatement efficiency preferably is 31.89%, the repair effect of three rounds of experiments respectively as 1.178mg/g, 2.379mg/g and 2.17mg/g. the mixed hanging biomembrane of natural zeolite’s subtractive efficiency is best 36.12%, the repair effect of three rounds of experiments respectively as 1.212mg/g, 2.412mg/g and 2.402mg/g. It is showed that the coating of the covered zeolite layer can continue to repair contaminated sediment... |
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