Pollution prevention and control in the toilet paper making process can be divided into two categories: in-plant on-site environmentally sound treatment and off-site wastewater treatment.

In-plant treatment

Including:

1. strengthen the preparation (dust, sediment, peeling, pith, etc.), the use of water film dust collector, reduce dust pollution in the preparation workshop, collection of waste, combustion recovery of thermal energy, such as the use of bark, wood chips, grass burner boiler;

2. water conservation, white water recycling, a number of times the water reuse;

3. to improve the extraction of cooking black liquor, strengthen the management of the counter current washing section to increase the number of sections, reduce the amount of cooking black liquor with the pulp taken away from the wash, and use the perfect cooking waste liquid recovery of chemicals and thermal energy technology, such as alkali recovery, and other waste liquid comprehensive utilisation. And use the perfect cooking waste liquid recovery of chemicals and thermal energy technology, such as alkali recovery, as well as other comprehensive utilization of waste liquid technology;

4. chlorine dioxide or oxy-alkali bleaching, or hydrogen peroxide bleaching, in order to reduce the wastewater lignin chloride, chlorophenol and other toxic emissions;

5. dirty condensate purified by steam extraction method for reuse to reduce the wastewater emissions of reduced sulfur and soluble organics;

6. collection of run-off and dripping black liquor, Green liquid, white liquid, with electronic computer control to measure its concentration, automatically sent back to the corresponding tank percussion, to reduce emissions;

7. recovery of lost fibers, reduce the content of suspended solids in wastewater;

8. to improve the recovery of turpentine sulphate soap, reduce the emission of toxic substances;

9. treatment of solid waste, the use of combustion to recover heat, comprehensive utilization and fill the pit of the three kinds of treatment;

10. treatment of dust, can be used in electric dust removal, water film dust removal and cyclone separator and other equipment; air pollution processing Separator and other equipment; air pollution treatment, collection of odorous gas in each workshop, including the odorous gas raised by dirty condensation water vapour, after cooling, dehydration, explosion-proof and other measures, sent to the boiler, alkali recovery furnace or lime kiln combustion treatment;? Noise treatment, take measures to eliminate vibration, sound insulation and switch to low-noise equipment.

Wastewater treatment outside the plant

Wastewater from the total discharge outlet of the whole plant is treated at the primary or secondary level before it is discharged into a water body, or the wastewater is used for irrigation and the soil and plants are used to purify the wastewater. Primary treatment mainly removes suspended matter, with methods such as sedimentation and filtration and air flotation. Individual plants add flocculants to the wastewater to remove some of the dissolved colloidal organic matter, such as lignin and pigments. General primary treatment can remove 80 ~ 90% SS and 20% BOD5. secondary treatment for biochemical treatment, mainly to remove BOD5. China has a few plants have been applied to this method, counting oxidation ponds, biofilters, bio-turntable and activated sludge (including adsorption and regeneration, accelerated aeration, contact oxidation). General secondary treatment can remove 60 ~ 95% BOD5. industrial developed countries, there are individual plants for wastewater tertiary decolourisation and purification treatment, so as to reach the level of drinking water, but the cost is expensive.

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Company Name: Sichuan Petrochemical Yashi Paper Co., Ltd.
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Country: China
Website: https://www.yashipaper.com/