γ-射线对不同含水率剩余污泥的影响

γ-ray Radiation Effects on Residual Sludge with Different Moisture Contents

采用溶解性化学需氧量(SCOD)、紫外可见光谱及污泥内源呼吸耗氧速率等指标,探讨了不同剂量γ-射线对不同含水率剩余污泥的辐照效果。结果表明,经γ-射线辐照处理后,污泥上清液的SCOD随着辐照剂量的升高而不断增加;相同辐照剂量下,污泥含水率越低,SCOD值增幅越大:原污泥SCOD均不足100 mg/L,经20 kGy辐照后,含水率99%、97%和90%污泥的SCOD分别增至348 mg/L、1 120 mg/L和2 050 mg/L。三种含水率污泥的上清液吸光度均随着辐照剂量的升高而增加,与未辐照样品相比,辐照后污泥上清液在240 nm^300 nm波段出现新吸收带。SCOD和UV-vis分析结果均表明,污泥细胞组分被γ-射线破碎。三种含水率污泥的内源呼吸耗氧速率均随着辐照剂量的升高而迅速降低,30 kGy时均接近0,表明污泥微生物在γ-射线辐照下被大量灭活。研究还表明,碱处理可以明显促进污泥的辐射溶解。

γ-ray radiation effects on residual sludge with different moisture contents were studied by measuring soluble COD（SCOD）,UV-vis spectra and endogenous respiration oxygen uptake rate（OUR）.Results showed that SCOD concentration increased with the increasing radiation dose,and more SCOD was generated by sludge with lower moisture content.With all the original SCOD less than 100 mg/L,SCOD was increased to 348,1,120 and 2,050 mg/L after 20 kGy irradiation with the moisture content of 99%,97% and 90% respectively.A new absorption band near 240 nm^300 nm for all irradiated samples indicated that cellular components of sludge were broken to smaller molecules.Endogenous respiration oxygen uptake rate of the irradiated sludge decreased rapidly with increasing of radiation dose,and were all near 0 after 30 kGy radiation for sludge with moisture content of 99%,97% and 90%,which showed that the majority of microorganism in the residual sludge were killed by γ-ray.Results also showed that alkaline pretreatment could significantly increase the hydrolysis of sludge cell components.