嗜酸性氧化亚铁硫杆菌对市政污泥脱水性能的改善

Improvement of municipal sludge dewaterability by Acidithiobacillus ferrooxidans

摘要:

为改善市政污泥脱水性能,利用嗜酸性氧化亚铁硫杆菌Acidithiobacillus ferrooxidans XJF8（简称At·fXJF8）对Fe²+矿化过程中的酸化作用,对污泥进行连续流深度脱水实验.生物酸化反应器为推流式,有效容积为68 L.通过pH、比阻、抽滤脱水前后泥饼含水率、有机质等指标研究了污泥脱水性能的变化.结果表明,营养剂投加量为2.11 g·L-1（以Fe(Ⅱ)计算）、污泥停留时间（SRT）为3.7 d、污泥回流比80%时,污泥pH由最初的7.22降至最终2.95左右,污泥比阻由原始污泥的(4.2±0.59)×10¹² m·kg-1（难脱水污泥）下降到(0.55±0.11) ×10¹² m·kg-1（易脱水污泥）,整个过程中Fe(Ⅱ)的氧化率在96%以上.对生物酸化铁氧化前后的污泥在0.05 MPa条件下进行抽滤脱水,泥饼含水率由80%下降到68%,且污泥有机质质量分数变化较小.At· fXJF8在污泥生物酸化铁氧化过程中具有良好的活性,在一定条件下可对市政污泥进行生物酸化铁氧化提高其脱水性能.

Abstract:

To improve the dewaterability of municipal sludge, the Acidithiobacillus ferrooxidans (At·fXJF8) cultivated in a laboratory-scale plug flow reactor (68 L) were used, which had efficient biomineralization and biological acidification. Chemical parameters of pH, specific resistance, suction filter mud cake moisture content of the municipal sludge was determined pre-and after dehydration etc. The optimum operation parameters of the reactor was: SRT 3.7 d, Fe(Ⅱ) dosage 2.11 g·L-1, reflux ratio 80%. Experiment result showed that the pH of the sludge decreased from 7.22 (stat-up stage) to 2.95 (steady stage) after the dewatering, and the specific resistance to filtration (SRF) of sludge decreased from initial (4.2±0.59)×10¹² m·kg-1 to the final (0.55±0.11)×10¹² m·kg-1. Ferrous oxidation rate kept above 96% in the whole running process. At the condition of 0.05 MPa pressure from the suction filtration, water content of the sludge decreased from 80% to 68%. This paper developed a new method for the sewage sludge dewaterability with the bio-acidification and ferrous oxidation by At· fXJF8.