Application of polyacrylamide in electroplating wastewater treatment

 

Industry Application

The traditional treatment method of electroplating wastewater treatment is chemical treatment (that is, adding flocculant to wastewater). This method has stable treatment effect, low treatment cost, convenient operation and management, but the sludge generated after treatment needs to be properly disposed of, for electroplating wastewater without recycling value should be treated by chemical method...

Applicable dehydration equipment

Filter press, plate and frame filter press, centrifuge, screw folding machine, etc

Specific agents,

Electroplating wastewater treatment and pretreatment process to use polyaluminum chloride and anionic polyacrylamide, according to the different concentration of sewage, the dosage of agents is also different, the higher the concentration, the greater the dosage, recommended dosage of about 30 ~ 100ppm (i.e. 0.03 ~ 0.1 kg/ton of wastewater).

details

The sources of electroplating wastewater are generally as follows:

 

(1) Plating cleaning water;

(2) waste electroplating solution;

(3) other waste water, including washing the workshop floor, scrubbing plate washing water, condensation water ventilation equipment, and due to leakage of plating tank or improper operation management caused by "running, running, dripping, leakage" various tank liquid and drainage;

 

(4) The cooling water of the equipment is not polluted except for the temperature rise in the process of use.

 

The quality and quantity of electroplating wastewater are related to the process conditions, production load, operation management and water consumption mode of electroplating production.

The water quality of electroplating wastewater is complex and the composition is not easy to control. It contains chromium, cadmium, nickel, copper, zinc, gold, silver and other heavy metal ions and cyanide, and some of them are carcinogenic, teratogenic and mutagenic highly toxic substances.

Therefore, the electroplating wastewater must be seriously recycled treatment, so as to eliminate or reduce its pollution to the environment.

 

The electroplating wastewater using the wastewater comprehensive treatment method are many, such as chemical method, ion exchange method, electrodialysis method, electrolytic process, etc., including chemical method is a more commonly used method, it is to join in the waste water containing hexavalent chromium ion reductant (such as the iron sulfate, sodium sulfite, iron powder, etc.), hexavalent chromium reduction into trivalent chromium, join the waste water treatment agent, sodium hydroxide, After adjusting the pH value of the wastewater, the heavy metal ions in the wastewater are precipitated, and then the pH value of the precipitated supernatant can be adjusted by adding acid before discharge. Using such wastewater treatment agent to treat electroplating wastewater, large amount of electroplating wastewater treatment process long, occupy more land, large investment, energy consumption, difficult operation and management, labor intensity of workers, high operation cost, but also can not ensure the steady operation of wastewater treatment. Therefore, it is urgent to provide a kind of electroplating wastewater treatment agent which can reduce the treatment cost and stabilize the treatment effect of secondary pollution.

 

 

The composition of electroplating wastewater is complex, except cyanide (CN-) wastewater and acid and alkali wastewater, heavy metal wastewater is potentially hazardous to electroplating industry.

According to the heavy metal elements contained in the wastewater is classified, generally can be divided into chromium (Cr) wastewater, nickel (Ni) wastewater, cadmium (Cd) wastewater, copper (Cu) wastewater, zinc (Zn) wastewater, gold (Au) wastewater, silver (Ag) wastewater. The common treatment methods of chromium-containing wastewater are reduction method and electrolysis method, with mature process and good operation effect.

 

Applicable equipment:

 

 

Electroplating sludge treatment by belt filter press dehydration, can dehydrate sludge to 80%-85% moisture content;

 

With plate frame filter press, box filter press, can be dehydrated to water content of 75%-83%;

 

With diaphragm filter press, can dehydrate to moisture content of 70%-78%.

 

Pharmaceutical selection:

 

In the latter stage, polyacrylamide should be used to deal with electroplating wastewater with inorganic flocculant. Practice has proved that the effect of anionic polyacrylamide with higher degree of hydrolysis is more prominent, and the general recommended degree of hydrolysis is 25-30.

 

Drug consumption per unit:

 

Electroplating wastewater treatment and pretreatment process to use polyaluminum chloride and anionic polyacrylamide, according to the different concentration of sewage, the dosage of agents is also different, the higher the concentration, the greater the dosage, recommended dosage of about 30 ~ 100ppm (i.e. 0.03 ~ 0.1 kg/ton of wastewater).