石灰投加对水厂排泥水造粒流化床处理工艺的影响

EFFECT OF LIME DOSAGE ON THE PROCESS OF PELLETING FLUIDIZED BED TECHNOLOGY IN A WATER WORKS

石灰作为一种传统的助凝剂,应用于水厂排泥水调质浓缩工艺,可提高污泥颗粒密度,改善污泥沉降脱水性能。本文利用造粒流化床处理工艺,以南方某水厂排泥水为处理对象进行中试试验,研究了石灰投加对工艺运行效果的影响。试验结果表明,石灰投加可减小PAM投药量,同时增大流化床最大上升流速。中试条件下,500mg/L的石灰投加量可在不影响出水水质的情况下,使流化床PAM投药量减少14%～24%,最大上升流速由38～50 cm/mi n增至42～57cm/min。与现行常规处理工艺相比,石灰投药量可由1667mg/L降至500mg/L左右,PAM投药量可节省50,%同时出泥沉降性能得到极大改善,含固率提高2～6倍。

In the wastewater conditioning and concentration process, lime can be used to raise density of the sludge particles, and improve the property of sludge dewatering. By taking the wastewater treatment of a water works in the southern of China as the object, the pelleting fluidized bed technology （PFBT） was used to concentrate the wastewater by dosing lime in the process under a pilot experimental scale. The experimental result indicated that lime could enhance the water flow rate of wastewater in the pelleting fluidized bed （PFB）, and save polyaerylamide （PAM） dosage. Under the pilot-experimental condition, the consumed dosage of PAM was saved by 14% in comparison with no lime added, and water flow rate in the PFB could reach to 42-57 cm/min with 500mg/L dosage of lime. Compared with the conventional gravity-concentration process, the lime dosage could reduce from 1667mg/L to 500mg/L, the PAM dosage could be saved by about 50%, sediment ability of sludge was improved dramatically, and the solid content in the concentrated sludge was raised by 2-6 times.