title: Removal of ammonia from landfill leachate by struvite precipitation with the use of low-cost phosphate and magnesium sources.
abstract: This paper presents a study concerning ammonia removal from landfill leachate by struvite precipitation with the use of waste phosphoric acid as the phosphate source. The results indicated that the Al(3+) ions present in the waste phosphoric acid significantly affected the struvite precipitation, and a removal ratio of ammonia close to that of pure phosphate salts could be achieved. Nevertheless, large amounts of NaOH were necessary to neutralize the H(+) present in the waste phosphoric acid. To overcome this problem, a low-cost magnesium source was proposed to be used as well as an alkali reagent in the struvite precipitation. The ammonia removal ratios were found to be 83%, with a remaining phosphate of 56 mg/L, by dosing the low-cost MgO in the Mg:N:P molar ratio of 3:1:1. An economic analysis showed that using waste phosphoric acid plus the low-cost MgO could save chemical costs by 68% compared with the use of pure chemicals. Post-treatment employment of a biological anaerobic filter process demonstrated that the high concentration of Mg(2+) remaining in the effluent of the struvite precipitation has no inhibitory effect on the performance of the biological treatment.
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, PR China. Electronic address: huanghaiming52hu@163.com.
authors.forename: Haiming
authors.initials: H
authors.lastname: Huang
authors.affiliation: Environmental Monitoring Center of Guizhou Province, Guiyang 550081, PR China.
authors.forename: Dean
authors.initials: D
authors.lastname: Xiao
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, PR China.
authors.forename: Qingrui
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Ding
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D011232:Chemical Precipitation; D005374:Filtration; D008274:Magnesium / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry*; D000069877:Struvite; D014865:Waste Disposal, Fluid / Q000191:economics / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D014874:Water Pollutants, Chemical; D000641:Ammonia; D000069877:Struvite; D008274:Magnesium
keywords: Ammonia nitrogen; Landfill leachate; Struvite precipitation; Waste phosphoric acid