Common measures of industrial wastewater treatment

The common way of industrial wastewater treatment is to add coagulant to flocculate and settle suspended solids, and at the same time, some pollutants such as ammonia nitrogen, heavy metal ions and organic matter are adsorbed and settled into human sludge. Sometimes, before adding coagulant, the high vessel filter of Haining first adds lime milk (Ca (OH) 2) to adjust the pH value of wastewater to 8-10 to produce copper hydroxide precipitation, and then pumps it into the sludge tank for drying treatment by sludge pump.
   in general, it is difficult to precipitate heavy metal ions completely only by adding lime milk. At the same time, because most heavy metal hydroxides are fine suspended or colloidal, it is difficult to settle naturally or the settling time is long. In order to accelerate the settling, it is necessary to add inorganic coagulant or organic polymer coagulant to produce chemical coagulation. On the other hand, after adjusting the value of lime milk, the alum formed by adding coagulant is large, the precipitation is fast, and the amount of coagulant is saved.
   at present, the widely used chemical coagulants are: ① basic polyaluminum chloride (PAC); ② polypropylene phthalein amine (pajm); ③ in addition, aluminum sulfate, ferrous sulfate, etc.
  in general, PAC is suitable because it has the following advantages:
   ① pH value has a wide range of application, and has flocculation effect in the range of 4-10;
   2. It has obvious removal effect on heavy metal ions in water;
   ③ it can not only effectively remove suspended solids in water, but also BOD, chroma, sulfide and odor in water.
   4. It has good demulsification and removal effect on emulsified oil in wastewater;
    5. It can break the complex wastewater;
   6 the dosage of chemicals is less, the amount of sludge produced is less, and the ratio of performance to price is excellent.
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