工艺特点 Technics Characteristic
       The innocuous treatment can be divided into two methods:precipitation method and adsorption method.Precipitation method ismainly used to remove suspended matter from wastewater and adsorption method is mainly to remove dissolved pollutants anddecolorization in wastewater.The chemical treatment methods include neutralization method, coagulation method and oxidationmethod.The neutralization method is to adjust the acidity and alkalinity of the wastewater,but  also to reduce the chroma of thewastewater.The coagulation method is to remove disperse dyes and colloids from the wastewater. The oxidation process is toreduce the substance in the oxidizing wastewater, so that the sulphide dye and the vat dye are precipitated. (3) the biologicaltreatment process includes activated sludge process, biological turntable process and biological contact oxidation process etc.In order to improve the effluent quality,the effluent can meet the discharge standard or Recovery requirements often need to betreated in combination with several methods
       Printing wastewater contains PS plate development waste liquid, offset press cots cleaning wastewater, in addition to acid andalkal, high chroma, the amount of waste water fluctuate. The COD value of ordinary domestic wastewater is less than 800 mg/L, while. the COD value of printing wastewater is more than 20000mg/L.Treatment is more difficult.Common treatmentmethods have recycling and harmless treatment.
       无害化处理可分:①物理处理法有沉淀法和吸附法等。沉淀法主要是去除废水中的悬浮物，吸附法主要是去除废水中溶解的污染物和脱色;②化学处理法有中和法、混凝法和氧化法等。中和法在于调节废水中的酸碱度，还可降低废水中的色度，混凝法在于去除废水中分散染料和胶体物质，氧化法在于氧化废水中还原物质，使硫化染料和还原染料沉淀下来;③生物处理法有活性污泥法、生物转盘和生物接触氧化法等。为了提高出水水质，达到排放标准或回收要求，往往需要采用几种方法联合处理。
     印刷废水包含PS版显影废液、胶印机胶辊清洗废水等，其除了含酸碱、色度高、废水来量波动大以外，还具有COD数值高的特征。普通生活废水的COD数值小于800mg/L，而印刷废水的COD数值超过20000mg/L，处理难度较大。常用的治理方法有回收利用和无害化处理。