免烧结微生物垃圾焚烧飞灰砖的抗压强度研究

针对当前城市垃圾焚烧飞灰(MSWI)处置费用高昂、环境污染严重等问题,提出一种利用微生物矿化原理制备免烧结垃圾焚烧飞灰砖的方法。通过在飞灰砖固结体中加入微生物菌液,利用微生物诱导碳酸盐沉积原理,实现飞灰中重金属的固化和稳定化。本文以垃圾焚烧飞灰、Ca(OH)₂、砂子、微生物菌液为原材料,通过单因素试验,探究了制备微生物飞灰砖最优的飞灰掺量、菌液浓度、营养液中钙离子浓度。试验结果表明,当飞灰掺量为40%(质量分数),菌液OD₆₀₀值为0.60,营养液中钙离子浓度为0.30 mol/L时,飞灰砖力学性能最优。此时规格为100 mm×100 mm×50 mm免烧结微生物飞灰砖的干密度为1 937.40 kg/m³,抗压强度达到33.90 MPa,并且重金属浸出浓度满足限值要求,实现垃圾焚烧飞灰的资源化利用。

Compressive Strength of Unburned Microbial Municipal Solid Waste Incineration Fly Ash Brick

In view of the high cost and serious environmental pollution caused by the disposal of municipal solid waste incineration(MSWI)fly ash,a method for preparing unburned microbial MSWI fly ash brick,using the principle of microbial mineralization,is proposed.The solidification and stabilization of heavy metals in MSWI fly ash were achieved by adding microbial bacteria liquid to the MSWI fly ash brick consolidation body and using the principle of microbial induced carbonate deposition.In this paper,MSWI fly ash,Ca(OH)₂,sand and microbial bacteria were used as raw materials,and the optimal MSWI fly ash content,microbial bacterial solution concentration and calcium ion concentration in nutrient solution for the preparation of microbial MSWI fly ash brick were explored through single factor experiment.The test results show that when the MSWI fly ash content is 40%(mass fraction),the OD₆₀₀ value of the microbial bacterial solution is 0.60,and the Ca²⁺ concentration in the nutrient solution is 0.30 mol/L,the mechanical properties of the MSWI fly ash brick are the best.At this time,the dry density of the 100 mm×100 mm×50 mm unburned microbial MSWI fly ash brick is 1937.40 kg/m³,the compressive strength reaches 33.90 MPa,and the heavy metal leaching concentration meets the limit requirement,realizing the resource utilization of MSWI fly ash.