城市污水处理厂污泥对水中硫化物的吸附特性

为研究城市污水厂污泥对水中硫化物的吸附特性,从3座城市污水处理厂采集回流污泥,考察了硫化物浓度、温度、pH值和其他离子对污泥吸附硫化物的影响.结果表明,污水厂回流污泥对硫化物的吸附等温线可以用Langmuir方程很好地描述,其最大硫化物吸附量为15~27mg/g-干污泥.在温度为5~35℃条件下,吸附量随温度上升而增加,表明该吸附为吸热过程.pH值在2~7范围内,pH值对污泥吸附硫化物的影响不大,当pH值低于2时,污泥对硫化物的吸附量随pH降低显著减小.硫化物可能以离子形式被污泥吸附,该过程为化学吸附过程.水中存在0~25mg/L Cl-或0~12mg/L SO2- 4不影响污泥对硫化物的吸附量.

Adsorption characteristics of sulfide onto the activated sludge of municipal wastewater treatment plants

In this study, activated sludge samples were collected from 3municipal wastewater treatment plants (WWTP) and the performance and impacting factors of sulfides adsorption onto the activated sludge were investigated. The impacting factors include sulfides concentration, temperature, pH and other anions. Adsorption isotherm of sulfide onto the activated sludge can be well described by Langmuir equation. The maximum sulfide adsorption capacity was 15~27mg/g-dry sludge. At the temperatures ranging from 5to 35℃, adsorption capacity increased by the rise in temperature and this implies the sulfides adsorption was an endothermic process. The pH value had little effect on the adsorption capacity from 2to 7. But the sulfides adsorption capacity decreased significantly when pH was lower than 2. Sulfides were adsorbed by activated sludge as anions (HS- and S2-) and it was a chemical adsorption process. Cl- ranging from 0 to 25mg/L or SO2- 4 ranging from 0 to 12mg/L did not affect the sulfides adsorption capacity.