疏浚底泥微波干燥及其作为种植土的性能研究

Study on Microwave Drying of Dredging Sludge and Performance of Sludge as Planting Soil

向含水率为60%的疏浚底泥中分别添加底泥质量(绝干)的1%、2%、5%的粉煤灰、生石灰、膨润土与稻壳进行微波干燥,探究这四种改良剂对底泥干燥性能及其结构、营养成分的影响。试验结果表明,微波功率为4 k W,传送速度0.64 m/min(传送频率为17.8 Hz),不通风的条件下,粉煤灰和生石灰可有效加快疏浚底泥的干燥速率,膨润土和稻壳对底泥连续化微波干燥特性影响不明显;粉煤灰、膨润土和稻壳能有效提高疏浚底泥的营养成分,降低底泥的容重,增大孔隙度,生石灰对底泥的营养成分和含盐量没有明显改善,但能够提高底泥的酸度值。试验为改良剂对疏浚底泥微波干燥性能及其作为种植土的应用提供了理论依据和技术支持。

In this study,different weight dry ratio（ 1%,2% and 5%） of fly ash,lime,bentonite and rice husk were added into dredged sludge with initial moisture content of 60% to improve the microwave drying performance and explore the effect of adding various types of amendment on the drying performance,structure and nutrient composition of dredged sludge. The result showed that the processes of drying sludge were effectively accelerated in the case of adding fly ash and lime when the microwave power set as 4 k W,transmission speed is 0. 64 m/min（ frequency is 17. 8 Hz）and no ventilation condition,but the influence of adding bentonite and rice husk in the same condition was not significant. When the dry sludge as planting soil,adding fly ash,bentonite or rice husk could enhance its content of nutrient,reduce the bulk density,and increase the porosity effectively.There was no significant improvement in the nutrient and salt content of the sludge when adding lime,but the acidity value would increase. The study provided a theoretical basis and technical support for improvement of microwave drying sludge by adding soil amendment sand the application of the dry sludge as planting soil.