How many hours is the hydraulic retention time for hydrolysis-acidification of papermaking wastewater?
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How does the acidification process for waste paper and papermaking wastewater work? I need help from an expert. The current pre-acidification level is around 65%. Inlet pH: 6.5; outlet pH: 5.5–6. Inlet flow rate: 150 cubic meters; tank capacity: 700 cubic meters. Very little sludge discharge; no N or P added. The COD of the inlet water was 2000, but the COD of the outlet water did not decrease. Sometimes it even gets higher.
This hydrolysis acidification is not primarily aimed at removing COD; it is a hydrolysis acidification process. Is the COD of the raw water already 2000? What we do is all in the range of 3,000–5,000; we use anaerobic processes! I have dealt with a lot of wastewater from recycled pulp paper production in China and Thailand
6000 of raw water passes through air flotation to yield 2000 of effluent, which is then subjected to hydrolysis and acidification
The COD removal rate using shallow air flotation is around 60%; when PAC, PAM are added, 2 liters of chemical per ton of water is used for treatment. Suspended particles the size of sorghum floated out. For PAM, use cationic + non-ionic types in a ratio of 4+6 kilograms. I would like to ask whether it is possible to increase the COD removal rate further. Our boss still doesn’t want to go anaerobic. Site limitations.
It is said online that hydrolysis-acidification can achieve a removal rate of 20%. What is your papermaking wastewater treatment process? Our plant uses shallow air flotation, hydrolysis-acidification, Carrousel oxidation ditches, and a two-stage sedimentation tank with cyclic operation. For advanced treatment, shallow air flotation units are employed (used when the concentration in the sedimentation tank is high); PAC is added during air flotation before the effluent exits, while polyferric sulfate is used during air flotation afterward
Are there any other ways to increase the removal rate?