“Flowing carbon method” treats printing and dyeing wastewater
“Flowing carbon method” treats printing and dyeing wastewater
After biochemical treatment of printing and dyeing wastewater, coagulation and sedimentation methods are generally used to further reduce pollutants. The removal rate of coagulation and sedimentation is generally around 30%. When the raw water mass concentration is high or the treatment requirements are very high, coagulation and sedimentation treatment cannot ensure that the wastewater is discharged up to standard. The cost of coagulation and sedimentation treatment is relatively high. For some sewage treatment plants with large treatment scale, the consumption of coagulation agents is considerable, accounting for a large proportion of the cost of wastewater treatment. After coagulation and sedimentation, the amount of sludge will be greatly increased, and sludge treatment is also a headache for sewage treatment plants. my country’s requirements for environmental protection are getting higher and higher. At that time, the problem of sludge disposal will become more prominent; activated carbon is used in wastewater treatment There are also applications in , but they are generally one-time use. The cost of wastewater treatment is very high, which limits the application of activated carbon in wastewater treatment.
“Flowing carbon method” is a new wastewater treatment process that I have been researching for many years. According to its processing principle, it is named “flowing carbon method”. Main application values: (1) Advanced treatment of printing and dyeing wastewater, replacing coagulation sedimentation (air flotation), oxidant decolorization, etc.; (2) Purification of river water with poor water quality; (3) Treatment of high-salinity chemical wastewater and characteristic pollution Handling of things. The application of “flowing carbon method” in printing and dyeing wastewater treatment has completed a small trial.
1 test
1.1 Materials and instruments
Materials: coconut shell activated carbon, JWl00 type, particle size 8-20 mesh, iodine adsorption value 900~1100mg/g, specific surface area 1200m2/g; activated sludge, printing and dyeing wastewater, centralized treatment of printing and dyeing wastewater (Changzhou Longcheng Wastewater Treatment Plant).
Instruments: 5B-1 CODcr rapid measuring instrument, MP120-2 electronic balance, tray balance, aeration device, stirring device, suction filtration device, several containers and glassware.
1.2 Activated carbon treatment
1.2.1 Saturated adsorption treatment
Take 20L of effluent from the primary sedimentation tank of the sewage plant and measure the CODcr mass concentration to be 876 mg/L. The total CODcr amount is calculated to be 17.52g. Weigh 6g of activated carbon, add 5L of wastewater, stir for 1 hour, filter out the activated carbon, and then add wastewater for adsorption, a total of 4 times. According to the adsorption capacity of activated carbon, it can be determined that the activated carbon has been adsorbed to saturation.
1.2.2 Activated carbon regeneration
After filtering out the adsorbed and saturated activated carbon, add the effluent from the secondary sedimentation tank (CODcr mass concentration 112mg/L) to prepare a 500mL aqueous solution. Add a small amount of activated sludge and aerate continuously for 48 hours before use.
1.3 Process
Take 5000mL of the effluent from the secondary sedimentation tank, add 500mL of the treated activated carbon solution, stir continuously for 30 minutes, and allow to settle for 1 hour. Separate 500mL of the precipitated activated carbon solution. After filtering the supernatant, measure the CODcr mass concentration and chromaticity. The activated carbon solution is anaerobic for 24h. , and then conduct the next batch of adsorption tests after aeration for 24 hours.
Repeat the above steps for the second batch of experiments.
1.4 Test
CODcr was analyzed using the potassium dichromate method (GB11914-89), and color was analyzed using the dilution multiple method (GB11903-89). The colorimetric and CODcr indicators are tested simultaneously, and the data is measured every 2 days.
2Results and Discussion
2.1 CODcr removal effect
As can be seen from Table 1, the “flowing carbon method” has a very high removal rate of CODcr, and conventional physical and chemical treatments rarely achieve such treatment effects.
2.2 Chroma removal effect
As can be seen from Table 2, the “flowing carbon method” has a more obvious removal rate of chroma, and the treated wastewater has a very good sense, which can effectively solve the problem of chroma emission in printing and dyeing wastewater (GB4287-1992 Intermediate Level 1 Standard) .
2.3 After the “flowing carbon method” processing cost analysis has been running for a period of time. Due to the growth of microorganisms, the amount of activated sludge gradually increases, and part of the sludge must be discharged. At this time, the activated carbon will be lost. It was found in the small test that the load during the biochemical regeneration of activated carbon was low and the anaerobic and aerobic processes were used for regeneration. The sludge growth rate was very slow. After 16 days, the sludge volume increased from 1.22g/L to 1.35g/L. However, the adsorption effect of activated carbon was not found to be weakened.
Excluding the loss of activated carbon, the main cost of “flowing carbon method” treatment is the electricity consumed during the regeneration process. The calculation method is basically the same as the calculation method of electricity consumption for biochemical treatment. The treatment cost is about 0.4 yuan/kgCODcr. For example, if the CODcr mass concentration of printing and dyeing wastewater is treated from 150mg/L to <100mg/L, the treatment cost per ton of wastewater is about 0.04 yuan. Far lower than the cost of coagulation precipitation and decolorization with oxidants.
3Conclusion
3.1 It is feasible to use microbial regeneration of activated carbon. The regenerated activated carbon has strong adsorption capacity. As an auxiliary method in the treatment of printing and dyeing wastewater, the “flowing carbon method” can greatly improve the quality of effluent water and reduce the cost of treatment.
3.2 This treatment process needs to be further improved. The treatment process should be developed from intermittent treatment to continuous treatment so that it can be matched with the existing treatment process of printing and dyeing wastewater; the amount of activated sludge increased during the test was not much. , no remaining sludge was discharged, therefore, the loss data of activated carbon during the treatment process was not obtained; the specifications of activated carbon need to be further optimized to improve the separation performance of activated carbon and wastewater. bVM4TK5Y3
Disclaimer:
Disclaimer: Some of the texts, pictures, audios, and videos of some articles published on this site are from the Internet and do not represent the views of this site. The copyrights belong to the original authors. If you find that the information reproduced on this website infringes upon your rights, please contact me if there is any infringement.We will change or delete it as soon as possible.
AA
