工藝特點 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.
       無害化處理可分:①物理處理法有沉淀法和吸附法等。沉淀法主要是去除廢水中的懸浮物，吸附法主要是去除廢水中溶解的污染物和脫色;②化學(xué)處理法有中和法、混凝法和氧化法等。中和法在于調(diào)節(jié)廢水中的酸堿度，還可降低廢水中的色度，混凝法在于去除廢水中分散染料和膠體物質(zhì)，氧化法在于氧化廢水中還原物質(zhì)，使硫化染料和還原染料沉淀下來;③生物處理法有活性污泥法、生物轉(zhuǎn)盤和生物接觸氧化法等。為了提高出水水質(zhì)，達到排放標(biāo)準(zhǔn)或回收要求，往往需要采用幾種方法聯(lián)合處理。
     印刷廢水包含PS版顯影廢液、膠印機膠輥清洗廢水等，其除了含酸堿、色度高、廢水來量波動大以外，還具有COD數(shù)值高的特征。普通生活廢水的COD數(shù)值小于800mg/L，而印刷廢水的COD數(shù)值超過20000mg/L，處理難度較大。常用的治理方法有回收利用和無害化處理。