Leachates generated in methanogenic landfills containhigh strength of ammonium nitrogen which removal ishard to be accomplished by means of conventional techniques.The chemical precipitation of struvite, which is a mineralthat could be reused as a slow-release fertilizer, is aneffective process in the removal and recovery of NH4 amountof high-concentrated wastewaters. In this paper, a struvite precipitationprocess using unconventional reagents is proposedfor a sustainable recovery of nitrogen content. In particular,seawater bittern, a by-product of marine salt manufacturing,and bone meal, a by-product of the thermal treatment of meatwaste, have been used as low-cost sources of magnesium andphosphorus, respectively. The process enables the removal ofmore than 98 % ammonia load, the recovery about 99 and95 % of phosphorus and magnesium, respectively, and theproduction of a precipitate containing struvite crystals.Heavy metals concentrations of produced precipitate were belowthe threshold values specified by the EC Directive for useof sewage sludges as fertilizers. Specific agronomic tests wereconducted to investigate the fertilizing value of precipitaterecovered from landfill leachate. The fertilizing effect ofstruvite deposit in cultivating Spinacia oleracea was comparedwith that of vegetable soil and commercial fertilizer.The growth of selected vegetable in the pots with struviteprecipitate resulted significantly greater in both than those inthe control pots and in the pots with the complex fertilizer.Furthermore, the struvite application as fertilizer did not resultin more heavy metals in the vegetables respect those from soil and model fertilizer.
Assessment of fertilizer potential of the struvite produced from the treatment of methanogenic landfill leachate using low-cost reagents
Alessio Siciliano
2016-01-01
Abstract
Leachates generated in methanogenic landfills containhigh strength of ammonium nitrogen which removal ishard to be accomplished by means of conventional techniques.The chemical precipitation of struvite, which is a mineralthat could be reused as a slow-release fertilizer, is aneffective process in the removal and recovery of NH4 amountof high-concentrated wastewaters. In this paper, a struvite precipitationprocess using unconventional reagents is proposedfor a sustainable recovery of nitrogen content. In particular,seawater bittern, a by-product of marine salt manufacturing,and bone meal, a by-product of the thermal treatment of meatwaste, have been used as low-cost sources of magnesium andphosphorus, respectively. The process enables the removal ofmore than 98 % ammonia load, the recovery about 99 and95 % of phosphorus and magnesium, respectively, and theproduction of a precipitate containing struvite crystals.Heavy metals concentrations of produced precipitate were belowthe threshold values specified by the EC Directive for useof sewage sludges as fertilizers. Specific agronomic tests wereconducted to investigate the fertilizing value of precipitaterecovered from landfill leachate. The fertilizing effect ofstruvite deposit in cultivating Spinacia oleracea was comparedwith that of vegetable soil and commercial fertilizer.The growth of selected vegetable in the pots with struviteprecipitate resulted significantly greater in both than those inthe control pots and in the pots with the complex fertilizer.Furthermore, the struvite application as fertilizer did not resultin more heavy metals in the vegetables respect those from soil and model fertilizer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
