进水盐度波动对污水处理厂处理效果的影响

发布时间：2018-03-01 07:14

  本文关键词： 城市污水处理 进水盐度波动 运行调控 硝化液回流比 水量调节　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国南方沿海某城市污水厂原水直接取自感潮河道,涨潮时,越来越多的海水回流进入感潮河道,导致污水厂进水盐度逐渐升高,而退潮时,与河道中污水混合的海水比例降低,污水厂进水盐度逐渐降低。伴随海洋潮汐变化,污水厂进水盐度在短时间内发生周期波动,对污水厂处理效果产生影响。目前,针对盐度对污水处理效果的影响主要集中于原水中盐度固定的条件下,而对原水中盐度周期波动的研究尚未见相关报道。本文在对深圳市某存在进水盐度波动的污水厂进行现状调研的基础上,结合实验室小试试验,考察了进水盐度波动对污水处理效果的影响,并研究了对应的调控措施。调研发现,全年进水盐度波动受降雨影响较大,雨季4～9月进水盐度波动范围较小,为0%～2‰;而旱季1～3月和10～12月,进水盐度波动范围达0‰～8‰。同时,雨季和旱季水温较高时,污染物去除效果较好,出水COD、NH_4~+-N和TN等均可达一级A排放标准;而旱季,因为盐度波动范围大、水温相对较低,虽对COD仍有较好去除效果,但出水NH_4~+-N和TN存在超标现象。根据调研结果,发现进水盐度波动和温度对实际污水厂运行效果影响较大,但由于实际污水厂原水等其他因素波动较大,难以真正确定盐度波动对处理效果的影响。因此,通过小试试验,在其他因素一致的情况下,系统研究不同盐度波动范围和温度对污水处理效果的影响。结果表明:在25±2℃和15±2℃下,盐度波动范围由0‰～2‰增大至0‰～10‰过程中,对COD去除均无明显影响,但对NH_4~+-N和TN的去除效果均随盐度波动范围增加而变差,并且,相同盐度波动条件下,15±2℃下的NH_4~+-N和TN去除效果更差,当盐度波动范围在0‰～4‰以上时,出水水质超过一级A排放标准。针对污水厂旱季进水温度低、盐度波动范围大时出水存在超标现象,考察水厂前端增建调节池、调节硝化液回流比和水量季节调配三种方式对处理效果的影响。试验结果表明:当进水盐度的波动范围为0‰～6‰时,前端增设0.3倍设计进水量的调节池或调节硝化液回流比为300%时,均能保证进水盐度波动范围控制在0‰～4‰,出水能达到一级A标准。对于水量季节调配方案,在雨季按1.3倍设计水量、旱季温度较高时按正常水量、较低时按0.5倍设计水量运行,可保证在出水水质达标的基础上,保证处理水量达到或超过设计值。
[Abstract]:The raw water of a municipal wastewater treatment plant in the southern coastal area of China is taken directly from the tidal channel. When the tide rises, more and more sea water flows back into the tidal channel, which leads to a gradual increase in the salinity of the influent of the wastewater treatment plant and a decrease in the tide. The ratio of seawater mixed with sewage in river decreases, and the salinity of influent of wastewater treatment plant decreases gradually. With the change of ocean tide, the salinity of influent in wastewater treatment plant fluctuates periodically in a short period of time, which has an effect on the treatment effect of wastewater treatment plant. The effect of salinity on sewage treatment is mainly concentrated in the condition of fixed salinity in raw water. However, the study on the periodic fluctuation of salinity in raw water has not been reported. Based on the investigation of the current situation of a wastewater treatment plant with influent salinity fluctuation in Shenzhen, combined with the laboratory test, The effect of influent salinity fluctuation on sewage treatment effect was investigated, and the corresponding control measures were studied. It was found that the influent salinity fluctuation was greatly affected by rainfall in the whole year, and the fluctuation range of influent salinity from 4 to September in the rainy season was small, which was 0 ~ 2 鈥，

本文编号：1550913