3000t/d tanning wastewater treatment process design
Abstract: The main content of this design is the design of tannery wastewater treatment process. As we all know, the quality of tannery wastewater is complicated, and it contains a lot of dyes, grease, sulfides, suspended solids, organic pollution, etc. causing serious pollution. Design content includes: design water quality 3000t/d; CODCr= 1500~3000mg/L; BOD5=800~1200mg/L; SS=700~1000mg/L; pH=6~9; color 200~400 times; Ammonia ni -trogen=100~200mg/L; Cr3+≤1000mg/L; S2-=50~100mg/L. According to the requirements of the relevant departments and the current environmental conditions, the quality of the effluent designed by the tanning wastewater and sewage treatment plant shall comply with the national first-grade standard for Integrated Wastewater Discharge Standard (GB8978-1996) and the Sewage and Pollutant Emission Standard for Leather and Fur Addition Industry (GB30486-2013) stricter standards in the industry standards, specific standards are as follows: CODCr=100mg/L; BOD5=30mg/L; SS=70mg/L; Ammonia nitrogen=15mg/L; S2-=1.0mg/L; pH=6~9; Cr3+=1.5mg/L; color 50 times.
The graduation project designed the treatment of tannery wastewater, including the design of structures and main treatment processes, the selection of processing equipment, the layout analysis of the plant site, and the economic analysis of the project. First, the wastewater is pretreated, chromium ions are removed, and the coarse and fine grids are sieved and then subjected to radial flow sedimentation tanks, aerated conditioning tanks, coagulation sedimentation tanks, oxidation ditch processes, vertical secondary sedimenta -tion tanks, and sludges. The layers of the various structures such as the thickening pond are treated so that the quality of the effluent can be fully discharged and discharged. The main process adopts the coagulation and sedimentation + oxidation ditch process, which has a higher removal rate of impurities such as SS, CODCr, BOD5, and chroma. The final treated effluent water quality can meet the national first-class standards and the stricter standards in the industry standards.
After a detailed engineering economic analysis of this graduation project, it is estimated that the total investment is about 6.651 million yuan, and the cost of wastewater treatment is 0.741 yuan/ton, which is lower than the similar kind of cost and has a better effect.
Key words: Tannery wastewater；Sewage treatment；Coagulation precipitation；Oxidation ditch