Chapter I Project Overview I. Design basis: 1, the owner to provide information; 2, the national comprehensive sewage discharge standard GB8978-1996; 3, domestic sewage treatment project design regulations DBJ08-71-98; 4, outdoor drainage design specifications GBJ14 -87 and related professional design specifications; 5, the city of regional ambient noise standards GB3096-93. Second, the source of raw water, water and water use: 1, the source of raw water: the community households living sewage. 2, the amount of water: the community households 1024, according to an average of 3.5 per household, a total of about 3,584 people. In view of the real estate company has not yet provided per capita water consumption, with reference to small cities in the south of China (<200,000 people), per capita residential water consumption of 148.5L / (person.d), and with reference to the high-level residential and villa per capita water consumption of 300 ~ 400L / (person.d), the average of the two take 250L / (person.d), temporarily as the basis for the project's accounting of the amount of water, then, the design of the project Processing water volume = 3584 people × 250L/(person.d) × 1.10 (unforeseen water volume) = 985.6m3/d, taking the same amount of domestic drainage and domestic water consumption (DBJ08-71-98). The design scale of the new water treatment station is 985.6 m3/d, and the average hourly treatment capacity is 41 m3/h. 3. Usage of water: watering for greening and landscape supplement water in the district. After treatment, the water is mainly used for toilet flushing, greening, car washing, etc. Therefore, it is required to meet the requirements of CJ25.1-89 "Miscellaneous Water Quality Standards for Daily Life". The main indicators are: COD ≤ 50 mg / L; BOD5 ≤ 10 mg / L; suspended solids ≤ 10 mg / L; turbidity ≤ 10 degrees; PH: 6.5-9.0; oil ≤ 3 mg / L; total coliform ≤ 3 / L; smell: no unpleasant sensations; free residual chlorine: the end of the pipe network is not less than 0.2 mg / L. 4, the proportion of reuse water ≥ 80%, and the rest of the wastewater treatment Up to standard discharge. Sewage intake and discharge of the main water quality indicators as shown in Table 1: Table 1: Sewage intake and discharge of the main water quality indicators CODcrmg / L BOD5mg / L SSmg / L plant and animal oils mg / L NH3 - Nmg / L PH
Intake of water 350-450 180-250 200-300 ≤ 40 35-40 6 - 9
Drainage water quality 100 20 70 10 15 6--9
Note: The treated effluent is required to meet the national comprehensive sewage discharge standard "GB8978-1996" in the first level. Chapter II Process Design Program I. Design Principles: 1. Strictly implement the relevant provisions of environmental protection to ensure that all water quality indicators of the treated water meet the standards and requirements of the design basis of this program. 2, the use of mature, functionally stable sewage treatment technology, and has a certain degree of flexibility, adjustability and emergency discharge measures. 3, the whole set of sewage treatment system, as far as possible, covers an area of small, low investment and low operating costs. 4, the main facilities using reinforced concrete structure, long service life; selection of equipment, instruments, accessories, materials, are of reliable quality, stable operation, easy to maintain. 5, give full consideration to the treatment process of secondary pollution (noise, odor, sludge treatment) prevention and control. 6, the scope of this design for access to the sewage treatment station catchment wells to the discharge pool until the sewage treatment process, electrical design of various specialties.
Second, the treatment method:
This project is proposed to use hydrolysis acidification - two-stage contact oxidation - filtration - disinfection process.
The sewage flows into the regulating pool after retaining large particles of dirt by the grating, and the regulating pool adopts the aeration type to equalize the water quality and quantity, and avoid the dirt precipitation through the aeration and mixing. The back of the regulating tank is equipped with a hydrolysis acidification section, using bacteria in anaerobic conditions within a short period of time, hydrolysis acidification reaction, degradation of large organic molecules in the sewage, is conducive to bacterial aerobic decomposition.
The aerobic treatment adopts two-stage biological contact oxidation. Biological contact oxidation is the most important part of the treatment process, where a large amount of organic matter is aerobically degraded by bacteria. The use of multi-stage segmented contact oxidation, the formation of a step-by-step load reduction system, so that the contact oxidation in the removal rate, shock load resistance, effluent water quality and other aspects of more advantageous and reliable.
Bio-contact oxidation effluent can be filtered and disinfected to complete the deep treatment of water reuse.
Three, process:
(Figure omitted)
According to the treatment process shown in the figure above, the role of each structure and description of the following:
In order to meet the discharge requirements, the treatment process adopts the biochemical treatment of the main treatment of the secondary treatment method of the A/O method, the treatment system consists of a collection of wells, regulating tanks, the A section of the biochemical tanks, O section of the biochemical tanks, sedimentation tanks, discharge tanks, tanks, water, water, water, water, water, water, water, water, water, water, water, and water, water, water. This treatment system consists of collecting well, regulating pool, section A biochemical pool, section O biochemical pool, sedimentation pool, discharge pool, water pool, sludge pool, machine room (fan, pump and electric control cabinet) and other structures.
Four, the main structures:
1, civil construction (this reinforced concrete equipment for the buried type, the top of the soil 0.3 meters can be green environment.)
Serial No. Name Specification (m) Quantity (seat) Remarks
1 Catchment well 1.5×6.5×4.5 1 Underground reinforced concrete structure
2 Conditioning tank 12.5×6.5×4.5 1 Ditto
3 Contact oxidizing tank 12.5×3.5×4.5 2 Ditto
4 Precipitation tank 9×3×4.5 1 Ditto
5 Sewage disposal tank 9×3×4.5 1 Ditto< /p>5
5 Sludge tank 9×3×4.5 1 Ditto
6 Discharge tank 4×4×4.5 1 Ditto
7 Middle tank 9×6×4.5 1 Ditto
8 Machine room 4×3.5×2.6 2 On the ground
V. Main equipment:
No.Name Model No.Specification Unit Amount Remarks
1 Mechanical grille 1
Mechanical grille 1
Model No. 1 Mechanical grille 1
2 Primary lifting pump 2 One with a spare
3 Roots fan 3
4 Secondary lifting pump 2 One with a spare
5 Quartz sand filter 1
6 Electromagnetic flowmeter 1
7 Disinfectant dosage device 1
8 Activated carbon filter 1
9 Sludge pump 2 1
9 Activated carbon filter 1
9 Sludge pump 1
9 Activated carbon filter 1
9 Activated carbon filter 1
9 9 Sludge pump Table 2 One for one
10 Combined packing set 1
11 Pipeline and flange elbow set 1
12 Valve equipment set 1
13 Manhole and valve cover set 1
14 Packing bracket set 1
15 Anticorrosive materials set 1
16 Electrical control system set 1
17 Power distribution equipment set 1
17 Power distribution equipment set 1
18 Polypropylene honeycomb inclined plate set 1
19 Liquid level controller set 1
Note 1: The total motor power of this wastewater treatment system is 55kw, and the operating power is 35kw.
Note 2: The facility occupies an area of about 350-400 m2 .
Note 3: The parameters of the above structures or equipment may be changed due to the design, subject to the construction drawings
2.2 Commonly used processes
According to the principle of wastewater treatment in the district, the treatment should be selected to achieve stable results, less mud production, energy-saving treatment methods. All kinds of buildings in the district system are generally built with septic tanks, so septic tanks should be combined with wastewater treatment methods. Commonly used process flow are:
① Sewage → grating → regulating tank → lifting pump → contact oxidation tank → sedimentation tank → water.
② sewage → grating → regulating pool → lifting pump →? Aeration tank →? Sedimentation tank Sludge reflux → effluent.
3) Sewage → grating → regulating pool → lifting pump → SBR pool or CASS pool → effluent.
④ Sewage → grating → regulating tank → lifting pump → coagulation and sedimentation (dosing) → filtration → effluent (physical and chemical method).
⑤ Sewage → grating → regulating tank → lifting pump → contact oxidation tank → coagulation and filtration (dosing) → effluent.
Domestic community sewage treatment design combined treatment plant was popular for a while, combined treatment refers to assembled or easy to assemble the stereotypes of the equipment, its main advantage is the construction of fast, does not occupy green space. But the actual application shows that there are many problems. Such as equipment maintenance management difficulties, the operation of the assessment of the inconvenience of a single machine to deal with the limited amount of water, service life, etc. are to be verified over time. According to the engineering design and actual operation experience, it is recommended that the daily capacity of more than 1000m3 of sewage treatment plant should be used above ground. In the amount of water is not large, the site is very tight when you can consider using buried equipment.