XIEYa-wei,YANJia-ming,HUANGYun-he,et al.Low-temperature Drying Technology and Its Practice in Drinking Water Plants[J].China Water & Wastewater,2024,40(5):9-15.
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Low-temperature Drying Technology and Its Practice in Drinking Water Plants

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第40卷 Number: 第5期 Page: 9-15 Column: Date of publication: 2024-03-01
Author(s):
XIE　Ya-wei1; 2;  YAN　Jia-ming1;  HUANG　Yun-he2; 3;  LIU　Hong-yuan1; 2;  ZHANG　Gang4;  SHEN　Dong-chun4;  WU　Hui4
（1. College of Civil Engineering， Zhejiang University of Technology， Hangzhou 310023， China； 2. Water Engineering and Emergency Technology R&D Center， Zhejiang University of Technology，Hangzhou 310023， China； 3. Hangzhou Water Group Co. Ltd.， Hangzhou 310014， China； 4. Jiaxing Water Investment Group Co. Ltd.， Jiaxing 314000， China）
Keywords:
sludge from drinking water plant;  low-temperature drying;  solar energy;  heat pump;  sludge property
Abstract:
In view of the high water content of drinking water plant sludge, this study investigated the operation effect of heat pump low-temperature drying in A, B and C water plants and its combination with solar energy in A water plant, and analyzed the factors affecting the operation effect of the drying equipment such as the nature of the dewatered sludge. The results showed that the water content of the sludge from the outlet of drying equipment of A and B water plants were stably less than 55%, and its corresponding specific moisture evaporation rate were (3.0±0.2) kg/(kW·h) and (3.2±0.2) kg/(kW·h), respectively. The specific moisture evaporation rate in C water plant was (3.8±0.2) kg/(kW·h), which was higher than that in A and B plants. However, the water content of its low-temperature dried sludge was higher than 60%, and it was not very meaningful to have a high specific moisture evaporation rate.The analysis of sludge properties showed that the choice and dosage of polyacrylamide (PAM) would affect the sludge viscosity, which indirectly affected the specific moisture evaporation rate; dewatered sludge powder, clay particles and adherent natural organic matter would enhance the sludge viscosity, which was not conducive to the improvement of specific moisture evaporation rate. The mechanical dewatering unit in the preliminaries of drying in C water plant exhibited poor effectiveness, resulting in the free water content of sludge after mechanical dewatering remaining as high as 183.1%. This led to inadequate drying of the sludge. During the operation of solar energy merely, the specific moisture evaporation rate of A water plant was higher than 8 kg/(kW·h) and the drying cost could be reduced by 75.5%.
Last Update: 2024-03-01