Abstract: This paper introduces the general situation of the sewage treatment plant in Huangpu Development Zone, Guangzhou.
Keywords: sewage treatment
1. Practice purpose:
Production practice is an important practical link for students to study in university. Internship is a compulsory course for every college graduate. It not only allows us to learn a lot of knowledge that we can't learn in class, but also broadens our horizons and increases our knowledge, laying a solid foundation for us to better apply what we have learned to practical work in the future. Through production practice, I can get in touch with professional knowledge more deeply, further understand the reality of environmental protection work, understand the problems existing in the process of environmental governance and the difficult problems that conflict between theory and practice, and write an internship report, so that I can learn to comprehensively apply what I have learned and improve my ability to analyze and solve professional problems.
II. Specific contents of the internship:
(1) West District Sewage Treatment Plant
Internship time: October 19, 24-November 29, 24
1. Overview of the sewage treatment plant:
The sewage treatment plant in Guangzhou Economic and Technological Development Zone is a key environmental protection project invested by the Development Zone Management Committee, and its main factory is located at No.22, Zhicheng Avenue West, Guangzhou Economic and Technological Development Zone. The daily treatment of industrial wastewater and domestic sewage is 3, tons, and the long-term plan is 9, tons.
Guangzhou Economic and Technological Development Zone Sewage Treatment Plant General Factory broke ground in September 1992 and was completed and put into operation in August 1994. Since the establishment of the factory, our factory has adhered to the implementation of total quality management, taking human management as the key to quality management, production operation management as the core of quality management, and equipment management as the basis of quality management, paying attention to every link, and ensuring that the effluent quality of sewage treatment all meets the design requirements and is superior to the national secondary discharge standards stipulated in the design. Attaching importance to and strengthening technical transformation has achieved good economic and social benefits in energy saving and consumption reduction. In 1999 and 21, it was rated as an advanced unit in the operation and management of urban sewage treatment plants in China and an advanced unit in Guangdong Province. Our factory is the designated practice base of South China University of Technology, South China Normal University and other institutions of higher learning.
in June p>21, our factory successfully passed the ISO14:1996 environmental management system certification, becoming the first municipal sewage treatment plant in China to pass the ISO14 environmental management system certification.
the factory has eight lifting pumping stations around the sewage treatment plant, the sewage treatment plant in the east zone (export processing zone) of Guangzhou Economic and Technological Development Zone, and the sewage treatment plant in Yonghe Economic Zone (Taiwanese investment zone) of Guangzhou Economic and Technological Development Zone. The general plant adopts the form of pumping water from peripheral pumping stations to collect and treat industrial wastewater and domestic sewage from the west area of Guangzhou Economic and Technological Development Zone. The main function of the plant is to be responsible for the safe and normal operation of the sewage pumping station, sewage treatment and sludge treatment, and to ensure that all the sewage entering the plant is discharged after treatment. The functional departments of the general factory include the director's office, deputy director's office, production department, technology department, general department and office.
The main positions of the production department are pumping station operation, sewage treatment operation, sludge treatment operation, laboratory test and warehouse management, etc.
2. Treatment process:
The West General Factory adopts the traditional activated sludge process with impeller surface aeration as the main body, all using domestic equipment. Sewage treatment adopts various methods to separate pollutants in sewage or convert them into harmless substances, so as to purify sewage. Classification of sewage treatment methods:
(1). Physical treatment method. Such as filtration and precipitation.
(2). Physical and chemical methods. Such as coagulation and precipitation.
(3). Biological treatment. Microbes are used to adsorb, decompose and oxidize the organic matter in sewage, and the unstable organic matter is degraded into stable and harmless substances, thus purifying the sewage. Activated sludge process is a kind of biological treatment process.
activated sludge process is the most widely used aerobic biochemical treatment technology for wastewater, which is mainly composed of aeration tank, secondary sedimentation tank, aeration system and sludge reflux system.
After the wastewater passes through the primary sedimentation tank, it enters the aeration tank together with the activated sludge flowing back from the bottom of the secondary sedimentation tank. After aeration, the activated sludge is suspended and fully contacts with the wastewater. Suspended solids and colloidal substances in wastewater are adsorbed by activated sludge, while soluble organic substances in wastewater are used by microorganisms in activated sludge as nutrients for self-reproduction, metabolized into substance cells, and oxidized into final products (mainly CO2). Insoluble organic matter needs to be converted into soluble organic matter before it can be metabolized and utilized. The waste water is thus purified. The purified wastewater and activated sludge are separated in the secondary sedimentation tank, and the upper effluent is discharged. Part of the separated and concentrated sludge is returned to the aeration tank to ensure a certain concentration of activated sludge in the aeration tank, and the rest is surplus sludge, which is discharged by the system.
The influencing factors of activated sludge reaction are as follows:
(1). BOD loading rate (F/M), Also known as organic loading rate (2), water temperature (3), pH value (4), dissolved oxygen (5) and nutrient balance (6). Toxic substances
aeration device:
1. Blowing aeration device
(1) Bubble aerator (3) Hydraulic shear type air aerator (4) Hydraulic impact type air aerator
2. Mechanical aerator
(1) Vertical shaft type mechanical aerator (2) Horizontal shaft type. (2) completely mixed activated sludge process
(3) sectional aeration activated sludge process
(4) adsorption-regeneration activated sludge process
(5) extended aeration activated sludge process
(6) high-load activated sludge process
(7) shallow aeration, deep-water aeration, Deep well aeration activated sludge process
(8) pure oxygen aeration activated sludge process
(9) oxidation ditch process
(1) sequencing batch activated sludge process
It is an economical and effective method to treat industrial wastewater with traditional aerobic activated sludge process, but the disadvantage is that the concentration of pollutants in wastewater will change, especially some pollutants with inhibitory effect have obvious inhibitory effect on bacterial activity. On the basis of the traditional method, aerobic activated sludge is domesticated, and the domesticated activated sludge can resist the inhibition of high-concentration pollutants. For example, the domesticated mixed bacteria can continuously degrade toxic organic chlorides, which effectively improves the purification effect. In addition, the sludge produced by the traditional activated sludge process is relatively large, which is also a big disadvantage of the traditional activated sludge process.
The schematic diagram of the process flow of the West General Factory is as follows:
The following figure is a bird's-eye view of the West General Factory:
3. Design parameters of the West General Factory:
◎ Treatment scale: the total design treatment scale is 9, tons/day, and the current first-phase design treatment scale is 3, tons/day.
◎ The main process adopted: the traditional activated sludge method with impeller surface aeration as the main method.
◎ Design inlet water quality: COD ≤ 5mg/LSS ≤ 25mg/LBOD5 ≤ 2mg/L
◎ Design outlet water quality: COD ≤ 12mg/LSS ≤ 3mg/L
Our factory implements the Discharge Limits of Local Standard Water Pollutants in Guangdong Province. The effluent quality standard is
COD ≤ 6mg/LSS ≤ 3mg/LBOD5 ≤ 3mg/L
The current actual treatment situation (the average daily treatment water volume is 24, tons, of which more than 7% is industrial wastewater. )
project
influent (mg/L)
effluent (mg/L)
treatment efficiency (%)
cod
544
48.1
91.2
BOD5
27
9.8
96.4
SS
278
28.7
89.7
. M)
effective volume (m3)
quantity
1
aerated grit chamber
aerated grit chamber
13.5× 2.5× 3.78
19
1
2
a sedimentation tank
radial sedimentation tank. H=5.65
114
2
3
aeration tank
surface aeration biochemical tank
12×12×4.5
648
1
4
secondary sedimentation tank
radial sedimentation tank < H=8.6
365
2
Main equipment
Equipment name
Model specification
Manufacturer
Quantity
Remarks
Grille cleaner
XGS135-12
Tangshan Qingyuan Environmental Protection Company
Pitch 1mm
Sand-water separator
LSSF-26B
Nanjing Lan Shen Pump Group
1
Sludge scraper for a sedimentation tank
D2
Jiangdu Water Supply and Drainage Equipment Factory
2
Single-arm peripheral drive amplitude-flow sludge scraper
Sludge pump for a sedimentation tank < 15
Anhui No.1 Textile Machinery Factory
1
SIEMENS inverter stepless speed regulation
sludge reflux pump
WQ-3-15
Nanjing Lan Shen Pump Group
4
secondary sedimentation tank scraper
D34
Jiangdu water supply and drainage equipment factory. -2
Henan Shangcheng Environmental Protection Factory
2
POWTRAN-RICH inverter stepless adjustment of filter belt speed
Roots blower
SSR-1
Shandong Zhanghuang Machinery Industry Co., Ltd.
2
SIEMENS inverter stepless speed regulation
excess sludge pump
AS75. Filter belt flushing pump
IS65-4-25
Hubei Shishou Water Pump Factory
2
Sludge delivery pump
8WJ412
Shanghai Ligong Pump Co., Ltd.
2
Chemical corrosion-resistant pump, SIEMENS inverter stepless speed regulation
dosing metering pump
JD
Tianjin General Machinery Factory
2
air compressor
V-.3/ 1
Guangzhou Tianhe Overseas Chinese Enterprise Company Huatong Compressor Factory
1
Mobile air compressor
Chlorine dioxide sterilizer
HT98-5
Shenzhen Outaihua Co., Ltd.
1
Main test items:
Chemical oxygen demand COD
Biochemical oxygen demand BOD5
Aeration. S
PH
total nitrogen
3-minute sedimentation ratio SV
sludge index SVI
ammonia nitrogen NH3-N
total phosphorus TP
phosphate po43-p
water content
organic matter
chloride
(2) Overview of the East District Sewage Treatment Plant:
Visiting time: November 28th, 24
1. Overview of the plant:
The East District Sewage Treatment Plant is located in Hongguang Road, East District (Export Processing Zone) of Guangzhou Economic and Technological Development Zone, which was built by the Guangzhou Economic and Technological Development Zone Management Committee with the international loan from Austria. The design treatment scale of the first phase is 26, tons/day, and the industrial and domestic sewage in the eastern area is treated by SBR process, basically using imported equipment, and the sewage enters the factory by gravity.
2. treatment process:
sequencing batch activated sludge process or intermittent activated sludge process, referred to as SBR process, is a remarkable wastewater treatment process in activated sludge treatment system in recent ten years. Literally, it means biochemical treatment of sewage in batches according to procedures.
SBR is a variant of the current activated sludge process, and its reaction mechanism and pollutant removal mechanism are basically the same as those of the traditional activated sludge process, but its operation is different.
SBR operation mode consists of five basic processes: water inflow, reaction, precipitation, water outflow and standby. From the beginning of sewage inflow to the end of standby time, it is counted as a cycle. In a cycle, all processes are carried out in a reaction tank with aeration or stirring device in turn, and this operation cycle is repeated repeatedly to achieve the purpose of continuous sewage treatment.
water inlet process: the water inlet process is the process of receiving sewage in the reaction tank.
reaction procedure: after the wastewater is injected to a predetermined volume, it is aerated or stirred to achieve the reaction purpose (BOD removal, nitrification, nitrogen and phosphorus removal).
sedimentation process: stop aeration and stirring, and perform gravity sedimentation and supernatant separation on activated sludge flocs.
drainage process: the supernatant after activated sludge precipitation is discharged as treated effluent until it reaches the lowest water level. Most of the activated sludge settled at the bottom of the reaction tank is used as reflux sludge in the next treatment cycle, and the excess sludge is discharged.
standby process: the period from precipitation to the beginning of the next cycle.
SBR process equipment and devices
(1). decanters: electromechanical rocker arm type, sleeve type, siphon type, rotary type, buoy type, etc.
(2) Aeration devices: mechanical aeration and blast aeration.
(3). Valve, sludge discharge system.
(4). Automatic control system.
the characteristics of SBR method are as follows:
(1). SBR method concentrates several steps of the biochemical treatment process, such as water inflow, aeration, sedimentation, drainage and idle regeneration, in one equipment or pool, so the basic process of treatment is to adjust the pool →SBR, and the process becomes very short, with few equipment, which is convenient for operation and maintenance.
(2). In SBR, besides aerobic biochemistry by aeration, there is also a long-term regeneration period when aerobic microorganisms can not bear the organic load and the hydrolysis process of anaerobic microorganisms. Therefore, SBR method has good sedimentation performance and clear effluent. Therefore, the high sludge concentration of SBR can be maintained, so that high load can be obtained, and it has extraordinary treatment efficiency and the ability to treat refractory sewage.
(3). During the operation cycle of SBR,