利用响应面法优化生物淋滤飞灰处理条件的研究

利用响应面法进行试验设计,选定蔗糖初始浓度、黑曲霉孢子浓度、投加的飞灰浓度以及飞灰投加时间作为影响因素,对生物淋滤城市生活垃圾焚烧飞灰的处理条件进行优化.通过响应面法,得到飞灰中Cd、Cr、Fe、Mn、Zn及重金属总量与4种因素之间的非线性回归方程,确定了生物淋滤的最适条件范围:蔗糖初始浓度为114~126g/L;黑曲霉孢子浓度为(1.6~2.1)×107个/mL;飞灰浓度为29~39g/L;飞灰投加时间为3.6~4.4d.在最适条件下,70g/L飞灰经20d生物淋滤后,溶出重金属总浓度降为901mg/L,占飞灰中重金属总量的41%,处理后飞灰的重金属浸出毒性远低于国家标准.

Optimization on bioleaching factors of municipal solid waste incineration fly ash using response surface methodology

The effectiveness of bioleaching is highly dependent on many biological factors. Four factors were investigated: sucrose concentration, spores concentration, fly ash concentration, and the time of fly ash addition. By using the central composite design, the non-linear equations, which described the relationship between the concentration of extracted heavy metals and the four factors above were obtained. Besides, the range of optimal bioleaching conditions were determined as follows: the concentration of sucrose, spores, fly ash was 114~126g/L, 1.6×107~2.1×107 spores/mL, 29~39g/L, respectively, and the time of fly ash addition was 3.6~4.4d. The trial was carried out in the optimum conditions by bioleaching 70g/L fly ash for 20 days. The concentration of extracted heavy metals was up to 901mg/L, which was 41% of the total heavy metals in fly ash.