What are the popular medical wastewater treatment processes?

The main purpose of medical sewage treatment is to disinfect and kill pathogens in medical sewage to prevent pathogens from causing infectious diseases. Medical sewage disinfection is generally carried out by drug disinfection.

1.Physical method: The use of physical action to treat, separate and ** pollutants in wastewater.

2.For example, the precipitation method (gravity separation method) removes suspended solids in water with a relative density greater than 1.

3.Filtration (activated carbon in the sand layer of the strainer) removes suspended solids from the water.

4.The evaporation method is used to concentrate non-volatile and insoluble substances in wastewater.

5.Chemical method: the use of chemical reactions or physicochemical reactions to treat **soluble wastes or colloidal substances.

6.For example, the neutralization method is used to neutralize acid, land-based or alkaline wastewater.

7.The extraction method uses the "allocation" of soluble wastes with different solubility in the two-phase interaction, such as phenols and heavy metals.

8.The redox method is used to remove reducing or oxidizing pollutants in wastewater and kill pathogenic bacteria in natural water bodies.

9.Biological method: the use of microbial biochemical action to treat organic pollutants in wastewater.

10.For example, biological filtration and activated sludge treatment of domestic sewage or organic production wastewater can be used to convert and degrade organic matter into inorganic salts and purify them.

11.Sludge land treatment method: used for organic matter treatment.

12.Sewage irrigation, slow infiltration, rapid infiltration.

For industrial wastewater treatment, the following processes can be used.

Chemical precipitation

Chemical precipitation method is widely used in industrial heavy metal wastewater treatment is a more effective method, is to add chemicals to the water body, through the precipitation reaction to remove heavy metal ions, mainly including hydroxide precipitation, sulfide precipitation and ferrite method.

The hydroxide precipitation method has the advantages of mature technology, low investment, low treatment cost and convenient management. Mirbagherzsa et al. used alkaline reagents, such as lime and sodium hydroxide, to treat copper-chromium-containing wastewater, and when the pH value was 12 and 12, Cu2+ and Cr3+ were completely precipitated, and the wastewater could be discharged up to the standard. Sing Heming et al. gradually adjusted the pH value of electroplating wastewater with sodium hydroxide solution, and precipitated copper, chromium, zinc and nickel in electroplating wastewater at multiple pH points, so that the heavy metal content in the wastewater was reduced to the minimum.

Although hydroxide precipitation can achieve the separation of heavy metal ions from wastewater, hydroxide precipitation also has disadvantages: for amphoteric hydroxides, if the pH value is not properly controlled, the heavy metal ions will dissolve again; The removal effect of heavy metals in dilute solution is not good; The sedimentation volume is large, the moisture content is high, and the filtration is difficult. At present, this method is rarely used in the treatment of heavy metal wastewater.

Electroflocculation

As a relatively mature wastewater treatment process, electrocoagulation method has been widely used. Ding Chunsheng et al. investigated the effects of initial pH value, electrolysis time, current intensity, NaCl dosage, ion coexistence and aeration capacity on the treatment of Cr6+ and Cu2+ wastewater by electrocoagulation method. The results show that at a certain pH value, when the current intensity is 4A, a relatively stable removal effect can be achieved in a very short time. At the same time, the coexistence of metal ions plays a role in promoting the treatment of heavy metal wastewater, and proper aeration will improve the removal rate of heavy metals.

The coagulation method should not be operated continuously for a long time, otherwise the surface of the electrode is easy to produce dense mucous membranes and form passivation.

Membrane separation

As a new type of separation technology, membrane separation technology can not only effectively purify wastewater but also provide some useful substances, and at the same time has the characteristics of energy saving, no phase change, simple equipment and convenient operation, so it has been widely used in wastewater treatment and shows broad development prospects. Its principle is to separate the solute and solvent in the solution through the selective permeability of the semi-permeable membrane, driven by external energy, so as to achieve the purpose of separation and purification. Membrane separation technology has the advantages of high efficiency, energy saving, and no secondary pollution, and has great development potential in the field of wastewater treatment.

However, the complex composition of industrial wastewater and the harsh treatment conditions make the membrane material must have good separation performance and long service life, and from this point of view, the development of high-performance membranes with excellent anti-pollution performance is of great strategic significance.