Composting domestic sewage sludge with natural zeolites in a rotary drum reactor.
This work aimed the influence of zeolites addition on a sludge-straw composting process using a pilot-scale rotary drum reactor. The type and concentration of three commercial natural zeolites were considered: a mordenite and two clinoptilolites (Klinolith and Zeocat). Mordenite caused the greatest carbon removal (58%), while the clinoptilolites halved losses of ammonium. All zeolites removed 100% of Ni, Cr, Pb, and significant amounts (more than 60%) of Cu, Zn and Hg. Zeocat displayed the greatest retention of ammonium and metals, and retention efficiencies increased as Zeocat concentration increased. The addition of 10% Zeocat produced compost compliant with Spanish regulations. Zeolites were separated from the final compost, and leaching studies suggested that zeolites leachates contained very low metals concentrations (<1 mg/kg). Thus, the final compost could be applied directly to soil, or metal-polluted zeolites could be separated from the compost prior to application. The different options have been discussed.
Villaseñor
J
J
Institute for Chemical and Environmental Technology (ITQUIMA), Department of Chemical Engineering, University of Castilla-La Mancha, Ciudad Real 13071, Spain. Jose.Villasenor@uclm.es
Rodríguez
L
L
Fernández
F J
FJ
D000641:Ammonia / Q000032:analysis; D000704:Analysis of Variance; D002244:Carbon / Q000032:analysis; D019216:Metals, Heavy / Q000302:isolation & purification; D009584:Nitrogen / Q000032:analysis; D010865:Pilot Projects; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D012722:Sewage / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D013696:Temperature; D013997:Time Factors; D014835:Volatilization; D014867:Water; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
D019216:Metals, Heavy; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D012987:Soil; D014874:Water Pollutants, Chemical; D014867:Water; D017641:Zeolites; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen