不同流态下微波辐射对污水污泥性质的影响研究

Effect of microwave radiation treatment on sewage sludge under different flow patterns

通过对不同流态下微波辐射对污水污泥性质的影响进行研究,考察了不同流态下微波辐射作用处理后污泥沉降性能、脱水性能的变化,以及微波辐射作用下流态对污泥挥发性悬浮固体(VSS)溶解率、上清液中COD和污泥微观形态的影响.结果表明,流态对污泥的沉降性能和脱水性能有一定影响,微波辐射功率越高,流态对污泥沉降性能和脱水性能的影响越显著.微波辐射功率较低时,雷诺数Re越大,污泥的沉降比(SV)、比阻和泥饼含水率越小;微波辐射功率较高时,Re为2300的临界流态下污泥的沉降性能和脱水性能最好.随着Re的增大,VSS溶解率和上清液中COD升高,微波辐射功率分别为300、500、700和900W时,Re为3000的紊流流态下上清液中COD分别达到1.1、2.1、3.6和6.7g·L-1.SEM观察结果表明,微波辐射及流态产生的协同剪切应时适宜时,有利于污泥颗粒的絮凝反应,高强度的微波辐射和紊流产生的较大剪切应力导致污泥絮体被打碎.

In the present study, the characteristics of the sewage sludge irradiated by microwave under different flows was investigated. The settling property, dehydration property, dissolution rate of the volatile suspended solids（ VSS）, COD of sludge supernatant and sludge micromorphology under microwave radiation were also analyzed. The results showed that the flow pattern had an effect on sludge settling properties and dehydration property. The microwave irradiation power had a significant effect on the sludge settling property and dehydration performance, and the effect was much obvious as the increasing of microwave irradiation power. When the power of microwave radiation was lower, the SV, specific resistance of sewage sludge and water content of sludge cake decreased with the increasing of Re. When the power of microwave radiation was higher, the best performance of settling property and dehydration property of sewage sludge occurred at the critical flow state with the Re of 2300. The VSS dissolving ratio and COD of supernatant increased with the increasing of Re. When the power of microwave radiation were 300, 500, 700 and 900 W, the COD in supernatant rose to 1.1, 2.1, 3.6 and 6.7 g·L^-1 respectively. The SEM picture of floes showed that the appropriate synergic shear stress caused by microwave radiation coalition with flow pattern was beneficial to flocculation, but the higher shear stress caused by high intense microwave radiation coalition with turbulence led to smashed sludge floes.