图片名称
Bangladesh Leather Wastewater Treatment Project

Bangladesh Leather Wastewater Treatment Project

1. Project overview: total investment of 65 million US dollars 2. Design scale: 20000 m³/d 3. Patented process: high denitrification combined Orbal oxidation ditch and other biochemical treatment of leather wastewater "invention patent, patent number: ZL200910184424.7"

Case description

1. Project overview: total investment of 65 million US dollars
 
2. Design scale: 20000 m³/d
 
3. Patented process: high denitrification combined Orbal oxidation ditch and other biochemical treatment of leather wastewater "invention patent, patent number: ZL200910184424.7"
 
  The sewage treatment project in Bangladesh Tannery Park contracted by Lingzhi Environmental Protection Co., Ltd. has a sewage treatment scale of 25,000 tons/day and a total contract value of more than 64 million US dollars. The project with the largest export value of environmental protection engineering general contracting in Jiangsu Province.
 
    The project adopts the patented process of "aeration conditioning tank + two-stage combined oxidation ditch + contact disinfection tank" to carry out physical treatment, chemical and biological treatment and mechanized sludge dewatering of tannery wastewater. The turnkey project for gravity and pressure flow sewage collection and delivery routes or other alternative systems covers almost 200 tannery plots, including nearly 160 tannery industries with a total water treatment capacity of 25,000m3/d.
 
The general contracting project of the leather sewage treatment project in Dhaka Tannery Park undertaken by Lexus Environmental Protection Co., Ltd. The conventional sewage treatment plant (CETP) has a total tanning wastewater treatment capacity of 25,000m3/d; the general contracting project covers 200 tannery plots , carrying out 2-module solid waste accumulation yard with a storage capacity of 100,000m3, equipped with a complete lining system, leachate collection and treatment system, mechanical accumulation and leveling system and monitoring facilities.
 
The designed water quality of the project is as follows:
 

serial number

project

unit

Influent water quality

Effluent quality

1

Biochemical oxygen demand BOD5

mg/L

2000

30

2

chemical oxygen demand CODCr

mg/L

4500

250

3

Suspended solids SS

mg/L

2500

100

4

Sulfide

mg/L

75

1.0

5

chromium

mg/L

115

2.0

6

grease

mg/L

20

10

7

Total dissolved substances TDS

mg/L

8000

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Introduction to the design scheme

 
This design document discusses the scale of the sewage treatment project of the Dhaka tannery, the quality of the influent and effluent of the sewage treatment plant, the sewage sludge treatment process, and the engineering design. The conclusions are as follows:
 
(1) Project scale
The total scale of Dhaka Tannery Wastewater Treatment Project is 2.0×104 m3/d, divided into 4 groups of modules, and the treatment scale of a single module is 0.5×104 m3/d. The total land area of ​​the project is 40857m2.
 
(2) Engineering design influent water quality
CODCr≤4500 mg/L, BOD5≤2000 mg/L, SS≤2500mg/L, sulfide≤75 mg/l, chromium content≤115mg/l, grease≤20mg/l, PH=7~9 
 
(3) The quality of the effluent of the project
CODCr≤250 mg/L, BOD5≤30 mg/L, SS≤100mg/L, sulfide≤1.0 mg/l, chromium content≤2.0mg/l, grease≤10mg/l, PH=6~9
 
(4) Sewage and sludge treatment process
The design adopts C-Orbal oxidation ditch as the main process of sewage treatment of this project, and makes full use of the characteristics of C-Orbal oxidation ditch process of water resistance, strong water quality impact load, and simple stage construction and expansion. 
Sludge treatment is recommended to adopt the belt-type thickening and dewatering integrated machine process.
Sewage outlet and sludge disposal After the sewage is treated, it will be discharged by gravity gravity into the Tolesori River after sludge treatment and sanitary landfill.
 
(5) Operating costs and environmental benefits
After the completion of the project, it can reduce CODCr emissions by 30,600 tons, BOD5 emissions by 14,184 tons, SS emissions by 17,280 tons, grease emissions by 72 tons, heavy metal chromium emissions by 813.6 tons, and sulfide emissions by 532.8 tons each year, with significant environmental benefits.
 
(6) Main production structures
The main production structures of this project are: fine grille and cyclone grit chamber, aeration adjustment tank, oxidation ditch of section A, oxidation ditch of section B, sludge homogenization tank, sludge concentration and dehydration machine room, sewage well, and discharge tank.
 

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