About water pollution treatment, and COD water pollution treatment

1: Your understanding and cognition of the principles, processes, equipment and engineering of biochemical treatment, especially anaerobic biological treatment process, as well as your knowledge of physicochemical methods and pretreatment. Like the Northeast, the anaerobic process is more widely used than the aerobic process, so I personally think that anaerobic biochemistry can be used as a sub-focus of personal ability in your resume, and it is best to write it close to the business scope and performance introduction on the company's homepage.

3: Your cognition and personal positioning of the industry, as well as the development status of the industry and personal development goals and positioning.

The main ones are these points, the other formats; The requirements and precautions should be written with reference to the general resume.

The concentration of domestic sewage when it enters the sewage treatment plant after being collected by the urban pipe network (total nitrogen is about 60, total phosphorus is about 5, ammonia nitrogen is about 40, and COD300 is about 300). Industrial wastewater is difficult to determine, different industries wastewater main pollutant types are different, for example, nitrogen fertilizer plant COD total phosphorus content is not low, ammonia nitrogen, total nitrogen concentration content is very high, and then for example, winery, COD content and wine aroma are related, discharge mode is also related, under normal circumstances, the bottom pot water and cooling water flushing water mixed discharge concentration COD can reach 4000-6000, ammonia nitrogen concentration of about 50. But if the bottom pot water alone discharges COD can be as high.

One, twenty thousand. The products, processes, and scales of various enterprises are different, and the emission concentrations are very different, so it is recommended that you consult the industrial pollution source emission coefficient manual.

Reasons: 1. Whether the water quality and quantity of the inlet water have changed (the water index of the inlet chain stool, etc.) 2. Whether the water temperature has changed;

3. The sludge state can be observed by microscopic examination (the proportion of each strain, activity, etc.) 4. Whether the sludge discharge is too much, or less (sludge expansion or insufficient sediment) 5. Whether the aeration volume changes (DO index).

Measures: 1. Extend the sludge discharge action, continuously discharge sludge 24 hours a day, and stabilize the sludge index first.

2. Flocculant is added to the secondary sedimentation tank to accelerate the sludge sedimentation speed.

3. Use COD degraders during system recovery to stabilize the emission of COD indicators.

The mixed COD of sewage and river water can be calculated by the following formula: mixed COD = sewage COD sewage flow + river COD river flow) sewage flow + river flow) where, sewage COD: indicates the concentration of sewage COD entering the mixed source water body, in mg L; Sewage Flow:

Indicates the flow rate of sewage entering a mixed water body in m h or l s; River COD: Indicates the concentration of river COD entering the mixed water body, in mg L; River Flow: Indicates the amount of river flow entering a mixed water body, in m h or l s.

Low COD concentrations will not have an effect, and the lower the COD, the better.

When the organic matter is pretreated (coagulation, clarification and filtration), it can be reduced by about 50%, but it cannot be removed in the desalination system, so it is often brought into the boiler through the make-up water to reduce the pH value of the furnace water. Sometimes organic matter can also be introduced into the steam system and condensate, lowering the pH and causing system corrosion. In circulating water systems, high levels of organic matter promote the growth of microorganisms.

Whether it is for desalination, furnace water or circulating water systems, the lower the COD, the better, but there is no uniform limitation. When the COD (KMNO4 method) is > 5 mg L in the circulating cooling water system, the water quality has begun to deteriorate.

1: Changes in the oxygen supply environment.

The sludge produced in the secondary sedimentation tank is mainly in the biofilm after falling off, because the biofilm is mainly aerobic bacteria, in the oxygen supply environment from aerobic to anaerobic, a large number of aerobic bacteria rupture, cytoplasm dissolution, part of the facultative bacteria and anaerobic bacteria use synthetic bacteria, part of the water body into the undegraded COD. Due to the presence of a large amount of sludge, the COD in the secondary sedimentation tank does not decrease but rises.

2: Self-factors.

The COD generated in the production of enterprises will be too high, such as residues in food factories, pickling wastewater in the electroplating industry, and reducing substances in chemical plants.

3: Imperfection in technology.

When the temperature and dissolved oxygen in the sewage are too low, the activity of the bacteria in the sewage decreases, and the normal metabolism cannot be achieved, so that the COD in the sewage can not be decomposed normally, once the COD concentration in the sewage is too high, it will poison the bacteria in the biochemical tank, and the COD concentration will rise after the bacteria are destroyed, so it will enter an infinite vicious circle.

So how to deal with high COD in wastewater?

Filtration adsorption method: the wastewater is pretreated and pumped into the filter, and most of the undissolved polymers and suspended solids can be removed after the wastewater is filtered, and the water is filtered out and then enters the activated carbon adsorption equipment, and the COD value in the wastewater is reduced through the adsorption of organic matter by activated carbon.

Oxidation method: the use of strong oxidation conditions to oxidize and decompose organic and polymer compounds. Commonly used oxidation methods are: combustion method, electrolytic oxidation method, chemical oxidation method, etc.

Acidification and coagulation secondary treatment method: at present, the commonly used method for the treatment of decoating ink wastewater in China is the method of using polymer polymer to condense into colloidal agglomeration under acidic conditions, and then filter and separate.

After taking the above methods or other process equipment treatment, the residual COD, it is difficult to meet the national emission standards if the method continues to continue, Xijie engineer suggests:

The residual COD wastewater can be treated with chemical agents, and the oxidation of chemical agents is used to decompose organic matter, and the organic matter decomposition efficiency under this method is fast, the treatment time is fast, and the chemical agent is generally directly added to the water outlet for use, without too much cumbersome operation.

For high COD industrial wastewater, there are several treatment methods.

1. Adopt high-efficiency flocculant pretreatment to reduce the COD of sewage and reduce the difficulty of water treatment in the later stage of sewage treatment

Iron salt series flocculant.

Polyferric sulfate, ferrous sulfate, ferrous chloride, ferrous sulfate, ferrous formate, iron sulfate, ferric chloride, ferric chloride and ferric formate, etc.

Aluminum salt series flocculant.

Aluminum sulfate, polyaluminum sulfate, aluminum chloride, polyaluminum chloride, polyaluminum chloride sulfate, polyaluminum chloride silicate, aluminum formate, polyaluminum formate, crystalline aluminum chloride and sodium aluminate, etc.

Polyacrylamide series flocculants.

Anionic polyacrylamide Cationic polyacrylamide Nonionic polyacrylamide.

2. Oxidant is used to oxidize and decompose organic COD in sewage, commonly used oxidant:

Sodium hypochlorite, hydrogen peroxide, potassium ferrate, potassium permanganate, ozone, persulfate, percarbonate, calcium hypochlorite, etc.

3. For sewage up to hundreds of thousands of COD, the method of sewage incineration can be considered to spray and burn high-concentration organic matter into carbon dioxide and water to completely decompose COD.

Fourth, the low concentration of COD after pretreatment can be further reduced by biochemistry.

The use of high-efficiency flocculants, such as ferrous sulfate, ferrous chloride, etc., to pre-treat to reduce the COD of sewage and reduce the difficulty of sewage treatment in the later stage. Then sodium hypochlorite, hydrogen peroxide, etc. are used to oxidize and decompose the COD in the sewage.

1. Efficient flocculant treatment, 2. Oxidant, 3. Sewage incineration, 4. Biochemical.

Remove the garbage and rinse it with clean water.

The oxygen tank is aerated for more than 12 hours.

Evolutionary treatment of microorganisms in sewage.

Chemical Oxygen Demand (COD) is a chemical measurement of the amount of reducing substances that need to be oxidized in a water sample. The oxygen equivalent of substances (usually organics) that can be oxidized by strong oxidants in wastewater, wastewater treatment plant effluent, and contaminated water. It is an important and rapidly determined organic pollution parameter in the study of river pollution and the properties of industrial wastewater, as well as in the operation and management of wastewater treatment plants, and is often represented by the symbol COD.