Introduction:
Treatment of wastewater containing heavy metals: the process of purifying the heavy metals contained in the sewage to meet the water quality requirements for drainage of a certain water body or reuse.
Technology:
At present, the treatment methods of heavy metal wastewater can be roughly divided into three categories:
(1) Chemical method: chemical precipitation method, electrolysis method, chelation method, nano heavy metal treatment, etc
(2) Physical treatment methods: solvent extraction separation, ion exchange method, membrane separation technology, adsorption method, etc
(3) Biological treatment methods: biological adsorption, biological flocculation, phytoremediation, etc.
The company's heavy metal wastewater treatment projects mainly include ion exchange method, membrane separation technology, medium adsorption filtration and biological reaction.
Introduction:
Chemical oxygen demand (COD) is a chemical method to measure the amount of reducing substances in water samples that need to be oxidized. The oxygen equivalent of waste water, effluent from waste water treatment plant and polluted water that can be oxidized by strong oxidant (generally organic matter).
The water with high COD content is discharged into the natural water body, causing a large number of algae to grow, consuming a large amount of dissolved oxygen in the water, causing the anoxic death of aquatic organisms such as fish in the water body, damaging the ecosystem of the water body, and further causing the anaerobic odor of the water body, so that the water body loses its use function.
Technology:
1. Efficient flocculant pretreatment is adopted to reduce the COD of sewage and the difficulty of water treatment in the later stage of sewage treatment. Such as: iron salt series flocculant, aluminum salt series flocculant, polyacrylamide series flocculant, etc.
2. Oxidants are used to oxidize and decompose the organic matter COD in sewage. Common oxidants include sodium hypochlorite, hydrogen peroxide, potassium ferrate, potassium permanganate, ozone, persulfate, percarbonate, calcium hypochlorite, etc.
3. For the sewage with hundreds of thousands of COD, the method of sewage incineration can be considered to burn the high concentration organic matter spray into carbon dioxide and water to completely decompose cod.
4. After pretreatment, low concentration cod can be further reduced by biochemistry.
Characteristics of industrial oily waste liquid:
High COD concentration; High oil content; High content of suspended solids; It is difficult to demulsify and separate oil and water; The ingredients are complex and contain oils, emulsifiers, fungicides, etc., which are not easy to be biochemical.
Traditional treatment process:
Oil separator - oil-water separator (skimming unit) - centrifuge separation - dosing flocculation - Advanced Oxidation - Biochemistry
Limitations: 1. Poor oil-water separation effect; 2. Adding a large amount of chemicals, the long-term operation cost is high and the amount of sludge is large, which is not conducive to the later biochemical treatment; 3. The process flow is relatively complex, inconvenient to operate and difficult to maintain; 4. Large floor area and high investment
Compared with the traditional emulsion treatment process, tubular membrane technology has the following advantages:
The tubular membrane is not easy to pollute, easy to clean, and the effect is stable. It is suitable for the treatment of waste emulsion;
The tubular filtration has high precision, which can effectively intercept emulsified oil droplets, microorganisms and other impurities of more than tens of nanometers in the waste emulsion, so as to realize oil-water separation and water purification;
It is a pure physical separation process without adding chemicals, which is conducive to recycling;
Simple process, convenient operation, easy maintenance and management;
Tubular membrane filtration has the advantages of simple process, high strength and long service life.
