Summary of laboratory wastewater treatment methods!

With the rapid development of economy and society, environmental pollution has become a problem restricting social and economic development, which seriously threatens people's living environment and health. With the continuous increase of the number of laboratories, the number of wastewater also begins to grow, and the cost is becoming more and more complex. If the laboratory wastewater can not be effectively treated. It will do some harm to the environment and human health. So, how much do you know about the treatment of laboratory wastewater? Now let's learn together!

Laboratory Wastewater

Usually, the wastewater produced in the laboratory includes redundant samples, standard curve and sample analysis residue, invalid storage solution and washing solution, as well as a large amount of washing water. Almost all routine analysis items have the problem of wastewater pollution to varying degrees. Of course, the methods of wastewater treatment with different components are also different.

Common wastewater treatment methods

Generally, there are physical method, chemical method and biological method.

Physical method mainly uses physical action to separate suspended solids in wastewater;

Chemical method mainly uses chemical method to treat dissolved substances or colloidal substances in wastewater;

Biological method is mainly to remove colloid and dissolved organic matter from wastewater.

When the wastewater is discharged into the surface water, the treatment degree shall be determined according to the discharge requirements. At the same time, combined with the self purification capacity of the water body, the allowable load of the water body is usually determined according to the indicators of harmful substances and dissolved oxygen, that is, the allowable concentration discharged into the water body.

1、 Organic wastewater treatment

Organic wastewater mainly includes some titration solution, reaction solution and metal digestion solution including chloroform, carbon tetrachloride and sulfur dioxide. Among them, those with less toxicity can be directly discharged by diluting with water, while other toxic and harmful wastewater can be treated by distilled water, recycling or other treatment methods.

2、 Inorganic wastewater treatment

Inorganic wastewater mainly includes heavy metals such as mercury, zinc, copper, cadmium and nickel, heavy metal complexes and waste liquid containing a large amount of acid and alkali.

Mercury containing wastewater treatment: adjust the pH value of mercury containing wastewater to 8-9, add ferrous sulfate to form iron sulfide, and use iron sulfide precipitation as coprecipitation agent to accelerate the precipitation of mercury sulfide, then recover the mercury precipitation by electrolysis, and discharge the filtered supernatant after neutralization.

Treatment of chromium containing wastewater: add 10% ferrous sulfate solution into the waste liquid. At this time, iron ion can reduce hexavalent chromium to trivalent chromium, and then add nitrate lime to adjust the pH value of the solution to 6 ~ 8, heat it to 80 ℃ and place it overnight. When no chromium is detected in the filtrate, the separation and precipitation shall be carried out and the waste liquid shall be discharged.

Treatment of waste water containing lead: react with hydrated lime, adjust the pH to 8 ~ 9 to form precipitation, neutralize and treat the residual liquid after precipitation and filtration, and then discharge it.

3、 Treatment of acid and alkali containing wastewater

For experimental wastewater containing acid or alkali, neutralization and post-treatment are generally carried out according to the principle of acid and alkali. In the summary of the treatment process, it should be noted that a small number of times should be used during operation. During mixing, two kinds of wastewater with different pH should be fused. Generally, the corresponding discharge can be carried out by adjusting the pH value of the solution to 7.

4、 Special wastewater treatment

Wastewater containing radionuclides can be classified into long-life and short-life according to the half-life of radionuclides. The waste water with long-lived radionuclides and high concentration should be stored in several ways and treated by purification method after reaching a certain amount. Short lived radionuclide wastewater shall be treated by storage method, and must be disinfected. After treatment, it can be discharged only after meeting the requirements of discharge standards.

5、 Comprehensive wastewater treatment

The process of "water quality homogenization + neutralization filtration → neutralization coagulation → replacement internal electrolysis → biological adsorption tank → sedimentation tank and clean water tank" is adopted for treatment. In wastewater treatment, in order to protect the pH value on-line control system, neutralization filtration technology is adopted to ensure that the acid-base wastewater can reach the standard stably and save chemicals. Combined filler is used to realize sludge immobilization; Advanced ozone generator is used for disinfection in the disinfection treatment section, and pulse water distributor is used for sludge digestion to realize sludge reduction. The process can decompose complex organic matter and stably treat the influence of chemicals on the wastewater produced in the experimental wastewater.