Laboratory waste pretreatment and recycling methods

1. Recovery method

(1) Recycling

The large amount of organic waste liquid produced in the experiment can be recovered by distillation, and can be reused under the premise of meeting the requirements; some precious metals can be recovered by precipitation, crystallization, adsorption, ion exchange and other methods; in the experiment The cooling water can be used again after cooling.

(2) Dilution method

Laboratory wastes, such as certain heavy metals, flammable organic solvents soluble in water, etc., can be directly discharged into the sewer after proper dilution. The specific requirements shall be discharged in accordance with GB 8978 comprehensive sewage discharge standard.

(3) Neutralization method

Strong acid and alkali laboratory wastes can be carefully neutralized to an appropriate pH and then discharged directly. If the neutralized waste liquid contains other harmful substances, further treatment is required.

(4) Oxidation method

Compounds such as sulfides, cyanides, aldehydes, mercaptans and phenols can be oxidized into low-toxic and low-odor compounds.

(5) Reduction method

Oxidizing sulfites, peroxides, many organic chemicals and heavy metal solutions can be reduced to low-toxic substances. The waste liquid containing hexavalent chromium can be reduced to trivalent chromium by reducing agents such as acid and ferrous sulfate, and the mercury, lead and silver in the waste liquid can be precipitated and filtered out after reduction. Organic lead can also be removed by a similar method. Collect the processed concentrated liquid, put it in a container, and send it to a designated place for processing.

2. Laboratory waste disposal methods

(1) Trash can

For inert solid waste that is suitable for public health garbage disposal and does not cause harm to the handler, it can be directly thrown into the garbage can, but it must comply with the relevant provisions of the "Law of the People's Republic of China on the Prevention of Environmental Pollution by Solid Waste".

(2) Sewer discharge

The safe and harmless laboratory waste processed by the above pretreatment method meets the discharge requirements of relevant environmental protection laws and regulations and can be directly discharged through the sewer.

(3) Incineration and solvent recovery

Waste organic solvents that do not contain solid, corrosive or chemically reactive substances should be classified and collected. They can also be mixed with fuel and burned in a boiler room or power station.

(4) Laboratory packaging

Sort a small amount of liquid or solid laboratory waste according to poisons, oxidizers, flammables, corrosive acids and corrosive alkalis, and then collect them in double-layer sealed tanks and send them to designated safe places or specific garbage Field treatment.

(5) Curing

In a metal tank with an inner lining and an open upper end, add a compatible curing agent (such as frog stone, diatomaceous earth or soil) to the liquid laboratory waste after proper pretreatment. Containers used for curing should be carefully sealed and properly marked.

(6) Waste exchange

Pharmaceuticals or waste liquids that are not needed by a certain laboratory are not completely useless to other laboratories, and are used for effective information exchange. And under the principle of determining the classification, it can be exchanged and reused.