双膜法处理沿海城市污水处理厂出水的中试实验研究

发布时间：2018-05-10 05:08

  本文选题：双膜法 + 预处理　； 参考：《广州大学》2017年硕士论文

【摘要】：沿海地区由于地理位置限制,管道大部分铺设于海岸附近,加之海产品产业的发展,污水厂进水中盐分含量普遍较高,并存在显著的季节性周期变化,由此导致污水厂再生水TDS和Cl~-含量超标,限制了其园林绿化等一系列用途。本论文开展了双膜法处理沿海地区城市污水处理厂出水的中试实验研究,期望通过这一深度处理方法使再生水能够满足南方地区园林绿化用水的相关要求,解决深圳某污水厂的再生水利用问题。通过监测污水厂出水电导率,研究污水厂含盐量的变化规律;比选了混凝、砂滤、活性炭过滤等预处理技术,并优化了各单元技术的运行工况;在综合考虑进出水水质、产水能力、膜抗污染性能等因素的情况下,研究了超滤/反渗透工艺对沿海地区污水厂二级出水的处理效果,并对运行条件进行了优化;最后进行了膜选型以及一段系统与二段系统运行方式对比。预处理采用混凝与砂滤技术时,聚合氯化铝(PAC)优于聚合硫酸铁(PFS),混凝剂的最佳投加量为12 mg/L,此时对COD_(cr)的去除率为31%,对浊度的去除率为80%。一般情况下,砂滤罐较优的清洗周期为6h,当进水水质恶化时,可调整为3 h。为了抑制藻类的滋生和细菌对膜的污染,需投加次氯酸钠药剂。当次氯酸钠投加量小于2.4 mg/L时,活性炭能完全吸附游离余氯,当投加量大于2.4 mg/L时,活性炭过滤罐出水含有游离余氯,长期运行时会造成膜材料的老化,由此确定Na Cl O的最佳投加量为2.4 mg/L。活性炭过滤器使用过程中对有机物去除性能不佳,并引起后续保安过滤器上附满活性炭粉末,因此可不选用活性炭过滤器,采用NaHSO_3还原剩余余氯。超滤产水浊度维持在0.1NTU以下、稳定性好。超滤出水SDI_(15)位于1.5左右,能满足反渗透进水SDI_(15)≤5的相关要求。超滤对COD_(cr)最高去除率12%,对TP、NH_3-N、Cl~-、电导率等去除率接近0,超滤产水能保证出水符合反渗透进水水质要求,当原水氯化物含量低于500 mg/L时超滤产水可直接回用反渗透膜产水NH_3-N与TP低于0.1 mg/L,COD_(cr)含量低于10 mg/L,浊度低于0.1NTU,厂内氯化物含量最高达到6000 mg/L左右,反渗透膜脱盐率达到97%以上,产水氯化物小于等于180mg/L,低于再生水规定的250mg/L,因此反渗透膜产水能保证回用需求。A、B、C三种反渗透膜在0.8 MPa-1.0 MPa之间均表现为:水通量与脱盐率随进水压力的升高而升高,相同进水压力及回收率下单位膜面积的水通量B膜A膜C膜,脱盐率A膜C膜B膜。A膜在1.0 MPa时水通量仅为0.16 m~3/h,脱盐率为99.7%,B膜在0.8 MPa时水通量能达到0.28 m~3/h,脱盐率为98%,C膜在1.0 MPa时水通量0.28m~3/h,脱盐率为99.3%。三种膜均能保障脱盐需求,相同通量下B膜需要进水压力最小。一级二段反渗透膜运行模式较一级一段更加稳定。反渗透采用Na OH清洗效果明显。反渗透膜进行短期保存时可无相关保护措施,但长期保存必须添加NaHSO_3等还原剂保护。
[Abstract]:Due to the limitation of geographical location, most of the pipelines are laid near the coast. In addition to the development of seafood industry, the salt content in the influent of wastewater treatment plants is generally high, and there are significant seasonal periodic changes. As a result, the content of TDS and Cl- in the reclaimed water of the wastewater treatment plant exceeded the standard, which limited a series of uses such as garden greening and so on. In this paper, a pilot experiment was carried out to treat the effluent from municipal wastewater treatment plants in coastal areas by dual-membrane process. It is hoped that the reclaimed water can meet the requirements of landscape water in southern China by this advanced treatment method. To solve the problem of reclaimed water utilization in a wastewater treatment plant in Shenzhen. By monitoring the electrical conductivity of effluent from the wastewater treatment plant, the variation law of salt content in the wastewater treatment plant is studied. The pretreatment technologies such as coagulation, sand filtration and activated carbon filtration are compared, and the operating conditions of each unit technology are optimized, and the water quality of incoming and outgoing water is considered comprehensively. The treatment effect of ultrafiltration / reverse osmosis process on secondary effluent of sewage-treatment plant in coastal area was studied under the conditions of water production capacity and membrane anti-fouling performance, and the operation conditions were optimized. Finally, the membrane selection and the operation mode comparison between one stage system and two-stage system are carried out. When coagulation and sand filtration were used in pretreatment, the polyaluminium chloride (PAC) was superior to the polyferric sulfate (PFS). The optimum dosage of coagulant was 12 mg / L, and the removal rate of COD / C crr was 31% and the turbidity removal rate was 80%. In general, the optimal cleaning period of sand filter is 6 h, and when the water quality deteriorates, it can be adjusted to 3 h. In order to inhibit algae breeding and bacteria fouling the membrane, sodium hypochlorite should be added. When the dosage of sodium hypochlorite is less than 2.4 mg/L, activated carbon can completely adsorb free residual chlorine. When the dosage is more than 2.4 mg/L, the effluent of activated carbon filter tank contains free residual chlorine. The optimum dosage of NaCl O is 2.4 mg / L 路L ~ (-1) 路L ~ (-1) 路L ~ (-1). The removal performance of organic matter in the activated carbon filter is not good, and the follow-up security filter is filled with activated carbon powder. Therefore, the activated carbon filter can be used instead of the active carbon filter and the residual chlorine can be reduced by NaHSO_3. The turbidity of ultrafiltration water is kept below 0.1NTU and the stability is good. The SDI _ (15) of ultrafiltration water is about 1.5, which can meet the requirement of SDI _ (15) 鈮，

本文编号：1867910