The first chapter is about the project. Design basis: 1. Information provided by the owner; 2. National Integrated Wastewater Discharge Standard GB 8978-1996; 3. Code for Design of Domestic Sewage Treatment Engineering dbj08-71-98; 4. Code for Design of Outdoor Drainage (GBJ 14-87) and relevant professional design codes; 5. Urban Regional Environmental Noise Standard GB 3096-93. 2. Source of raw water, water quantity and use of reclaimed water: 1. Source of raw water: domestic sewage. 2. Water quantity: residential area 1024 households, with an average of 3.5 persons per household, totaling about 3,584 persons. In view of the fact that real estate companies do not provide per capita water consumption, refer to small cities in the south (
The influent quality is 350-450180-250 200-300 ≤ 40 35-40 6-9.
Drainage water quality100 207010156-9
Note: The treated effluent should meet the first-class standard in the national comprehensive wastewater discharge standard GB8978- 1996. Chapter II Process Design Scheme 1. Design principle: 1. Strictly implement the relevant regulations on environmental protection, and ensure that the water quality indexes of the treated tail water meet the standards and requirements in the design basis of this scheme. 2. Adopt mature and stable sewage treatment technology, which has certain flexibility, adjustability and emergency discharge measures. 3. The whole sewage treatment system should be as small as possible with low investment and operation cost. 4. The main facilities are reinforced concrete structures with long service life; The selected equipment, instruments, fittings and materials are reliable in quality, stable in operation and easy to maintain. 5. Fully consider the prevention and control of secondary pollution (noise, odor, sludge treatment) in the treatment process. 6. The design scope covers the sewage treatment process and electrical design from the collecting well to the discharge pool of the sewage treatment station.
Second, the treatment method:
Hydrolytic acidification-two-stage contact oxidation-filtration-disinfection process is proposed for this project. 、
The sewage is intercepted by the grid and flows into the regulating tank. The regulating tank adopts aeration to balance the water quality and quantity, and the sewage is prevented from settling by aeration and stirring. A hydrolytic acidification section is arranged behind the regulating tank, which utilizes the hydrolytic acidification reaction of bacteria in a short time under anaerobic conditions to degrade macromolecular organic matter in sewage, which is beneficial to the aerobic decomposition of bacteria.
Aerobic treatment adopts two-stage biological contact oxidation. Biological contact oxidation is the most important part of the treatment process, in which a large number of organic substances are aerobically degraded by bacteria. Multi-stage and segmented contact oxidation is adopted to form a step-by-step load reduction system, which makes contact oxidation more advantageous and reliable in removal rate, impact load and effluent quality.
After the biological contact oxidation effluent is filtered and disinfected, the advanced reclaimed water can be reused.
Third, the process flow:
(Figure omitted)
According to the treatment process shown in the above figure, the functions and descriptions of each structure are as follows:
In order to meet the emission requirements, the treatment process adopts a secondary treatment method based on biochemical treatment A/O method. This treatment system consists of water collecting well, regulating tank, Class A biochemical tank, Class O biochemical tank, sedimentation tank, discharge tank, intermediate tank, sludge tank, machine room (fan, water pump, electric control cabinet) and other structures.
Four, the main structures:
1, civil engineering (this kind of reinforced concrete equipment is buried, and the top can be covered with 0.3 meters of soil to green the environment. )
Sequence number. Name specification (m) Quantity (block) Note
1 sump 1.5×6.5×4.5 1 underground reinforced concrete structure
2 regulating tank 12.5×6.5×4.5 1 ditto.
3 Contact oxidation tank 12.5×3.5×4.5 2 Same as above.
4 sedimentation tank 9×3×4.5 1 ditto
5 Sludge pond 9×3×4.5 1 ditto.
6 Discharge tank 4×4×4.5 1 ditto.
7 zhongchi 9×6×4.5 1 ditto.
The machine room 4×3.5×2.6 2 is located on the ground.
V. Main equipment:
Serial number name model specification unit quantity remarks
1 mechanical grid table
Table 2 One-stage lifting pump, one for use and one for standby
Roots blower table 3
4 Two-stage lift pump Table 2: One for use and one for standby
5 quartz sand filtering platform 1
6 electromagnetic flowmeter 1
7 disinfectant dosing device settings 1
8 activated carbon filter platform 1
9 Sludge Pump Table 2 One for use and one for standby
10 combined packaging set 1
1 1 pipe and flange elbow sleeve 1
12 valve equipment group 1
13 manhole and bonnet 1
14 packaging support sleeve 1
15 anticorrosion material sleeve 1
16 electrical control system settings 1
17 distribution equipment group 1
18 polypropylene honeycomb inclined plate sleeve 1
19 liquid level controller sleeve 1
Note 1: The total motor power of this sewage treatment system is 55kw, and the operating power is 35kw.
Note 2: The facility covers an area of about 350-400 square meters.
Note 3: The parameters of the above structure or equipment will be changed due to the design, and the construction drawing shall prevail.
2.2 General process
According to the principle of sewage treatment in residential area, the treatment method with stable treatment effect, less sludge production and energy saving is selected. Septic tanks are generally built in various buildings in the community system, so septic tanks should be combined with sewage treatment methods. Commonly used technological processes are:
① Sewage → Grille → Regulating Pool → Lift Pump → Contact Oxidation Pool → Sedimentation Pool → Effluent.
② Sewage → Grille → Regulating Pool → Lift Pump →? Aeration tank? →? Sedimentation tank? Sludge reflux → effluent.
③ Sewage → grille → regulating pool → lifting pump →SBR pool or CASS pool → effluent.
④ Sewage → grille → regulating tank → lift pump → coagulation and sedimentation (dosing) → filtration → effluent (physicochemical method).
⑤ Sewage → Grille → Regulating Pool → Lift Pump → Contact Oxidation Pool → Coagulation and Filtration (dosing) → Effluent.
In the design of domestic residential sewage treatment, the combined treatment device was once all the rage. Combined treatment refers to the setting equipment that is assembled or easy to assemble. Its main advantages are fast construction speed and no occupation of green space. But the practical application shows that there are many problems. For example, it is difficult to maintain and manage the equipment, it is inconvenient to check the operation situation, the water treatment capacity of a single machine is limited, and the service life needs time to verify. According to the engineering design and practical operation experience, it is suggested to adopt the above-ground sewage treatment plant with daily treatment capacity of 1000m3. In the case of a small amount of water and a very tight site, buried equipment can be considered.