Methods of treating sewage

Commonly used products

Product category:

Sewage treatment products commonly used are: quartz sand filter material, anthracite filter material, polyaluminum chloride, activated carbon, honeycomb inclined tube packing, fiber ball filter material, garnet sand and so on

Polyacrylamide (PAM) is a water-soluble polymer, insoluble in most organic solvents, has good flocculation, can reduce the friction resistance between liquids, according to ionic characteristics can be divided into non-ionic, anion, cation and amphoteric four types.

Product characteristics

1, flocculation: PAM can make suspended substances through electric neutralization, bridge adsorption, flocculation.

2, adhesion: through mechanical, physical, chemical action, play a bonding role.

3, resistance reduction: PAM can effectively reduce the friction resistance of the fluid, adding a trace of PAM in the water can reduce the resistance of 50-80%.

4, thickening: PAM has a thickening effect under neutral and acid conditions, when the PH value is above 10 PAM is easy to hydrolysis. The thickening will be more pronounced when the structure is semi-reticulated.

Instructions for use

1, the number of cationic polyacrylamide used for coal washing can be set at 30 kilograms to 110, should increase the number of use, the number of use is set at 100 to 300 kilograms is more reasonable, electroplating wastewater industry and ordinary industrial water generally do not exceed 50 kilograms. Note: (The amount used in these industries is the amount of waste water per thousand tons)!

2, the application of polyacrylamide in the textile industry.

If the main process adopts biochemical methods, that is, the dehydration of the remaining sludge (which may contain some initial sediment), only cationic PAM is needed as a sludge dehydrating agent.

If the process body uses physical and chemical methods, such as first-level strengthening, loading magnetic separation and other processes, it is generally added between kilograms first; The amount of wastewater used in the chemical industry is generally between 50 and 120 kilograms; The wastewater of bleaching and dyeing industry and the wastewater of paper industry are the most difficult to deal with PAC tempering, and then add anionic flocculant, and finally add cationic flocculant dehydration. The specific dosage should be determined according to the sewage quality.

There are also many sewage treatment stations, sludge dehydration directly add PAC or other inorganic flocculants can be, this is widely used in plate and frame filter press, especially electronics plants or small sewage treatment stations.

When PAM is used as a sludge dehydrating agent, the ratio of PAM to water is generally between 0.1% and 0.2%. After it is dissolved into a glue-like liquid, it is added to the sludge for mixing treatment.

The ratio with the sludge is generally 5%-10%, and some are lower, which should be determined according to the concentration of the sludge, and it is best to determine the best dosage and use model through the beaker experiment on site. Different sludge, different agents, different equipment, different management levels, the treatment effect of sludge is different.

3, the sewage treatment plant uses cationic polyacrylamide as sewage operation sludge dehydrating agent. In the process of communicating with customers, customers often ask about the amount of sludge dewatering agent added in the process of sewage treatment sludge dewatering. To know the dosage of sludge dehydrant relatively accurately, first understand these parameters, the moisture content of sludge, the moisture content of mud cake, the amount of mud, the amount of medicine, the concentration of medicine and so on

Sludge moisture content: The percentage of the weight of water contained in the sludge to the total weight of the sludge is called the sludge moisture content.

Mud cake moisture content: The percentage of the weight of water contained in the mud cake to the total weight of the sludge is called mud cake moisture content.

Also through the following formula to calculate:

1, dosage mg/L= dosage quality/treatment water/dosage concentration

2, treatment water dosage = treatment water m3/h* dosage g/m3

3, dry mud amount = water treatment * [(1- sludge moisture content)/(1- mud cake moisture content)]

4, per ton of dry mud drug consumption g/m3= dosage/amount of dry mud

The error of the above calculation results may be relatively large, and it is only for reference during sewage operation. The actual drug consumption should be tested by actual machine operation.

Water treatment agent used in sewage treatment - flocculant

There are many kinds of sewage treatment agents, the most commonly used is flocculant, flocculant can be divided into inorganic and organic two kinds.

Inorganic flocculant

Inorganic flocculants are divided into low molecular weight and high molecular weight according to the size of the molecular weight.

A, low molecular inorganic flocculant

The most widely used amorphous flocculants are iron series and aluminum series metal salts. The mainstream inorganic coagulants in the market are ferric chloride, ferrous sulfate and aluminum sulfate.

The aqueous formula of ferric chloride is (FeCl3·6H20).

Characteristics: The formed alum has good precipitation, the treatment of low temperature water or low turbidity water effect is better than aluminum salt, the suitable pH range is wider, but the color of the treated water is higher than that of the aluminum series, and it is corrosive.

The molecular formula of ferrous sulfate is (FeS04·H20).

Features: The dissociated Fe2+ can only generate the simplest mononuclear complex, which is not as good as the coagulation effect of the trivalent iron salt.

The molecular formula for aluminum sulfate is Al2(S04)3

Features: Aluminum sulfate is the most used flocculant in wastewater treatment, easy to use, good flocculation effect;

Disadvantages: When the water temperature is low, hydrolysis is difficult, and the floc formed is looser; It has a narrow range of effective pH values.

Mingiso (Al2(S04)3·K2S04.24H20) is similar to aluminum sulfate.

Second, polymer inorganic flocculant

Inorganic polymer flocculant is the most used flocculant with high coagulant effect and low price. According to the different ionic degree can be divided into cationic type and anionic type

Cationic type: polyaluminum chloride, polyaluminum sulfate, polyaluminum phosphate, polyferric sulfate, polyaluminum ferric chloride, etc.

There are few varieties of anionic inorganic flocculants, and the more mainstream in 2013 is polymeric silicic acid.

Treatment agent:

There are many kinds of sewage treatment agents, the most commonly used is flocculant, flocculant can be divided into inorganic flocculant and organic flocculant.

Inorganic flocculant

Inorganic flocculants are divided into low molecular weight and high molecular weight inorganic flocculants according to the size of molecular weight.

Low molecular weight inorganic flocculant

The most widely used are iron series and aluminum series metal salts. The mainstream of the market are aluminum chloride, ferric chloride, ferrous sulfate and aluminum sulfate.

Aqueous formula of ferric chloride (FeCl3·6H20)

Characteristics: The formed alum has good precipitation, the treatment of low temperature water or low turbidity water effect is better than aluminum salt, the suitable pH range is wider, but the color of the treated water is higher than that of the aluminum series, and it is corrosive.

The molecular formula of ferrous sulfate is (FeS04·H20).

Features: The dissociated Fe2+ can only generate the simplest mononuclear complex, which is not as good as the trivalent iron salt.

The molecular formula for aluminum sulfate is Al2(S04)3

Features: It is the most used flocculant in wastewater treatment, easy to use, good flocculation effect, when the water temperature is low, hydrolysis is difficult, the formation of floc is loose, its effective pH range is narrow.

The action mechanism of Mingiso (Al2(S04)3·K2S04.24H20) is similar to that of aluminum sulfate.

Polymer inorganic flocculant

Inorganic molecular flocculant is the most mainstream inorganic flocculant with high coagulant effect and low price. The varieties of inorganic polymer flocculants can be divided into cationic type and anionic type according to different ionic degree

Cationic type: polyaluminum chloride, polyaluminum sulfate, polyaluminum phosphate, polyferric sulfate, polyferric chloride, polyferric phosphate, polyferrous and so on.

cpolyaluminium chloride (cpolyaluminium chLoricle) is a new type of mainstream inorganic polymer flocculant. Due to its higher efficacy than traditional inorganic chemicals in water treatment, it will be rapidly developed and widely used.

There are fewer varieties of anionic inorganic flocculants, and the more mainstream is polymeric silicic acid in 2013.

Organic flocculant

Organic flocculants are divided into ionic and non-ionic types.

Ionic organic flocculants can not only change the surface charge of particles, but also act as bridging chains to cause flocculation. Such as polyacrylamide (also known as 3 flocculants). Used to accelerate the rapid settlement of thickening concentrate. This reduces the water content of the concentrate and reduces metal loss.

Organic flocculants are generally relatively large molecular weights, usually tens of thousands, hundreds of thousands, or even millions, so adding a small amount can play a bridge chain role.