Abstract: This article introduces the overall situation of the sewage treatment plant in Huangpu Development Zone, Guangzhou.
Keywords: sewage treatment
1. Internship purpose:
Production internship is an important practical part of students' university studies. Internship is a compulsory course for every college graduate. It not only allows us to learn a lot of knowledge that we cannot learn in class, but also broadens our horizons and increases our knowledge, so that we can better apply the knowledge we have learned in the future. Apply it to practical work to lay a solid foundation. Through production internships, I have deepened my professional knowledge, further understood the reality of environmental protection work, understood the problems existing in the environmental governance process and the difficult issues that conflict between theory and practice, and through writing internship reports, I have learned to comprehensively apply what I have learned. knowledge and improve the ability to analyze and solve professional problems.
2. Specific content of the internship:
(1) West District Sewage Treatment Plant
Internship time: October 19, 2004 - November 29, 2004
1. Overview of the sewage 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. The main plant is located in the Guangzhou Economic and Technological Development Zone. No. 22 Chengda Avenue West (Xiji Industrial Zone), covering an area of ??78,600 square meters. The daily treatment of industrial wastewater and domestic sewage is 30,000 tons, with a long-term plan of 90,000 tons.
The Guangzhou Economic and Technological Development Zone Wastewater Treatment Plant broke ground in September 1992 and was completed and put into operation in August 1994. Since its establishment, 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. We pay attention to every link to ensure sewage treatment. The effluent quality all meets the design requirements and is better than the national secondary discharge standards stipulated in the design. Attaching importance to and strengthening technological transformation, we have achieved good economic and social benefits in terms of energy conservation and consumption reduction. In 1999 and 2001, it was rated as an advanced unit in the operation and management of urban sewage treatment plants in the country and an advanced unit in Guangdong Province. Our factory is a designated internship base for colleges and universities such as South China University of Technology and South China Normal University.
In June 2001, our factory successfully passed the ISO14000:1996 environmental management system certification and became the first urban sewage treatment plant in the country to pass the ISO14000 environmental management system certification.
The plant has jurisdiction over 8 lifting pumping stations around the main sewage treatment plant, the sewage treatment plant in the East District of Guangzhou Economic and Technological Development Zone (Export Processing Zone), and the Yonghe Economic Zone of Guangzhou Economic and Technological Development Zone (Taiwanese Investment Zone ) sewage treatment plant. The main plant uses peripheral pumping stations to lift and deliver water to collect and treat industrial wastewater and domestic sewage in 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 sewage pumping stations, sewage treatment, and sludge treatment, and to ensure that all sewage entering the plant meets the standards for discharge after treatment. The functional departments of the main factory include the director's office, deputy director's office, production department, technical department, comprehensive department, office, etc.
The main positions of the production department include pump station operation, sewage treatment operation, sludge treatment operation, laboratory testing and warehouse management, etc.
2. Treatment process:
The West District General Plant adopts the traditional activated sludge process with impeller surface aeration as the main body, and all uses domestic equipment. Sewage treatment uses various methods to separate or convert pollutants in sewage into harmless substances, thereby purifying sewage. Classification of sewage treatment methods:
(1). Physical treatment method. Such as filtration method and precipitation method.
(2). Physical and chemical methods. Such as coagulation sedimentation method.
(3). Biological treatment method. Microorganisms are used to adsorb, decompose, and oxidize organic matter in sewage, and degrade unstable organic matter into stable and harmless substances, thereby purifying sewage. The activated sludge method is a type of biological treatment method.
The activated sludge process is the most widely used aerobic biochemical treatment technology for wastewater. It mainly consists of an aeration tank, a secondary sedimentation tank, an aeration system and a sludge return system.
After the wastewater passes through the primary sedimentation tank, it enters the aeration tank at the same time as the activated sludge flowing back from the bottom of the secondary sedimentation. Through aeration, the activated sludge is in a suspended state and fully contacts the wastewater. Suspended solids and colloidal substances in wastewater are adsorbed by activated sludge, while soluble organic matter in wastewater is used by microorganisms in activated sludge as nutrients for their own reproduction, metabolized into material 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 wastewater is thus purified. The purified wastewater and activated sludge are separated in the secondary sedimentation tank, and the upper layer effluent is discharged. A part of the separated and concentrated sludge is returned to the aeration tank to ensure that a certain concentration of activated sludge is maintained in the aeration tank, and the rest is residual sludge. discharged from the system.
The influencing factors of activated sludge reaction are as follows:
(1). BOD loading rate (F/M), also called organic loading rate (2). Water temperature (3). PH value (4). Dissolved oxygen (5). Nutrient balance (6). Toxic substances
Aeration device:
1. Air blast aeration device
(1) Microbubble aerator (2) Medium bubble aerator (3) Hydraulic shear air aerator (4) Hydraulic impact air aerator
2. Mechanical aerator
(1) Vertical axis mechanical aerator (2) Horizontal axis mechanical aerator
3. Main operations of activated sludge process Method
(1) Pulse flow activated sludge method
(2) Completely mixed activated sludge method
(3) Staged aeration activated sludge method Mud method
(4) Adsorption-regeneration activated sludge method
(5) Delayed aeration activated sludge method
(6) High load activity Sludge method
(7) Shallow aeration, deep water aeration, deep well aeration activated sludge method
(8) Pure oxygen aeration activated sludge method
(9) Oxidation ditch process
(10) Batch activated sludge method
Using the traditional aerobic activated sludge method to treat industrial wastewater is an economical method. , a method with good purification effect, but the disadvantage is that the concentration of pollutants in the wastewater will change, especially some inhibitory pollutants that have a significant inhibitory effect on bacterial activity. On the basis of the traditional method, aerobic activated sludge is domesticated. The domesticated activated sludge can resist the inhibitory effect of high concentrations of pollutants. For example, the domesticated mixed bacteria can continuously degrade toxic organic chlorides, effectively improving the purification efficiency. Effect. In addition, the traditional activated sludge method produces a relatively large amount of sludge, which is also a relatively large shortcoming of the traditional activated sludge method.
The process flow diagram of the West District General Plant is as follows:
The following picture is a bird’s-eye view rendering of the West District General Plant:
3. Design parameters of the West District General Plant:
p>
◎Processing scale: The total designed processing scale is 90,000 tons/day, and the current first phase designed processing scale is 30,000 tons/day.
◎The main process used: the traditional activated sludge method based on impeller surface aeration.
◎Designed water quality: COD≤500mg/LSS≤250mg/LBOD5≤200mg/L
◎Designed water quality: COD≤120mg/LSS≤30mg/LBOD5≤30mg/ L
Our factory implements the "Guangdong Province Local Standard Water Pollutant Discharge Limits" (DB44/26-2001), and the effluent water quality standard is
COD≤60mg/LSS≤30mg/ LBOD5≤30mg/L
The current actual treatment situation (the average daily water treatment volume is 24,000 tons, of which more than 70% is industrial wastewater.
)
Project
Inlet water (mg/L)
Output water (mg/L)
Treatment efficiency ()
COD
544
48.1
91.2
BOD5
270
9.8
96.4
SS
278
28.7
89.7
Main structures:
Serial number
Structure name
Structure type
Specifications (L×B×H, m)
Effective volume (m3)
Quantity
1
Aeration grit tank
Aeration grit tank
p>13.5×2.5×3.78
109
1
2
One sinking tank
Radial sedimentation tank
D=20, H=5.65
1104
2
3
Aeration tank
Surface aeration biochemical tank
12×12×4.5
648
10
4
Secondary sedimentation tank
Radial flow sedimentation tank
D=34, H=4.15
3282
2
5
Concentration tank
Gravity concentration tank
D=9, H=8.6
365
2
Main equipment
Equipment name
Model specifications
Manufacturer
p>Quantity
Remarks
Grid Cleaner
XGS1350-1200
Tangshan Qingyuan Environmental Protection Company
p>1
Gate distance 10mm, pitch 100mm
Sand water separator
LSSF-260B
Nanjing Blue Shenzhen Pump Group
1
A sedimentation tank mud scraper
D20
Jiangdu Water Supply and Drainage Equipment Manufacturing Factory
2
Single-arm peripheral drive amplitude flow mud scraper
One sedimentation tank mud pump
AS55-4CB
Nanjing Lanshen Pump Group
2
Aerator
PE150
Anhui First Textile Machinery Factory
10
SIEMENS frequency converter stepless speed regulation
Sludge return pump
WQ-300-15
Nanjing Blue Shenzhen Shenzhen Pump Group
4
Secondary sedimentation tank scraper and suction machine
D34
Jiangdu Water Supply and Drainage Equipment Manufacturing Factory
2
Arm-arm peripheral drive amplitude flow scraper and suction machine
Belt filter press
DYL-2000
Henan Shangcheng Environmental Protection Factory
2
POWTRAN-RICH frequency converter steplessly adjusts the filter belt speed
Roots blower
SSR -100
Shandong Zhanghuang Machinery Industry Co., Ltd.
2
SIEMENS frequency converter stepless speed regulation
Residual sludge pump
AS75-4CB
Nanjing Lanshen Pump Group
2
Filter belt flushing pump
IS65- 40-250
Hubei Shishou Water Pump Factory
2
Sludge Transfer Pump
80WJ4012
Shanghai Benefit workers
Pump Industry Co., Ltd.
2
Chemical corrosion-resistant pump, SIEMENS frequency converter stepless speed regulation
Dosing metering pump
JD
Tianjin General Machinery Factory
2
Air Compressor
V-0.3/10
Guangzhou Tianhe Overseas Chinese Enterprise Company Huatong Compressor Factory
1
Mobile air compressor
Chlorine dioxide sterilizer
HT908- 500
Shenzhen Outaihua Co., Ltd.
1
Main laboratory items:
Chemical Oxygen Demand COD
Biochemical oxygen demand BOD5
Aeration tank mixed liquid MLSS
Return sludge MLSS
Suspended solids SS
PH value
p>Total nitrogen TN
30-minute sedimentation ratio SV
Sludge index SVI
Ammonia nitrogen NH3-N
Total Phosphorus TP
Phosphate PO43--P
Moisture content
Organic matter
Chloride
(II ) Overview of the East District Sewage Treatment Plant:
Visit time: the morning of November 28, 2004
1. Overview of the plant:
The East District Sewage Treatment Plant is located in Guangzhou Economic Hongguang Road in the East Area of ??the Technology Development Zone (Export Processing Zone) was built by the Guangzhou Economic and Technological Development Zone Management Committee using international funds from Austria. The designed treatment capacity of the first phase is 26,000 tons/day. It treats industrial and domestic sewage in the East District using the SBR process. Basically, imported equipment is used, and the sewage enters the plant in a gravity-flow manner.
2. Treatment process:
Sequential batch activated sludge method or intermittent activated sludge method, referred to as SBR process, is the most popular method in activated sludge treatment system in the past ten years. One of the more eye-catching wastewater treatment processes literally means biochemical treatment of sewage in batches according to procedures.
SBR is a variant of the current activated sludge process. Its reaction mechanism and pollutant removal mechanism are basically the same as those of the traditional activated sludge process, only the operation is different.
The SBR operating mode consists of five basic processes: water inlet, reaction, precipitation, water outlet and standby. The period from the beginning of sewage inflow to the end of the standby time is counted as one cycle. In one cycle, all processes are carried out sequentially in a reaction tank equipped with an aeration or stirring device. This operation cycle is repeated over and over again to achieve the purpose of continuous sewage treatment.
Water inlet process: The water inlet process is the process of accepting sewage into the reaction tank.
Reaction process: When the wastewater injection reaches the predetermined volume, aeration or stirring is performed to achieve the purpose of the reaction (BOD removal, nitrification, denitrification and dephosphorization).
Sedimentation process: Stop aeration and stirring, and the activated sludge fluff undergoes gravity sedimentation and supernatant separation.
Drainage process: discharge the supernatant after activated sludge sedimentation as treated effluent until it is discharged to the lowest water level. Most of the activated sludge settled at the bottom of the reaction tank is used as return 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). Decanter: electric mechanical rocker type, sleeve type, siphon type, rotary type, pontoon type, etc.
(2). Aeration device: mechanical aeration, blast aeration.
(3). Valve and mud discharge system.
(4). Automatic control system.
The characteristics of the SBR method are as follows:
(1). The SBR method combines the water inlet, aeration, sedimentation, drainage and idle regeneration of the biochemical treatment process. They are all concentrated in one equipment or pool, so the basic process of treatment is regulating pool → SBR. The process becomes very short and the equipment is small, making it easy to operate and maintain.
(2). In SBR, in addition to aerobic biochemistry with aeration, there is also a longer regeneration period in which aerobic microorganisms do not bear the organic load, as well as the regeneration period of anaerobic microorganisms. hydrolysis process. Therefore, the SBR method has good settling performance and clear water. Therefore, the SBR can maintain a high sludge concentration, thereby achieving a high load, and has extraordinary treatment efficiency and the ability to treat refractory sewage.
(3). During the operation cycle of the SBR, the time of water inlet, aeration, settlement, drainage, idle and other procedures can be adjusted according to the actual water quality and quantity, so it is highly adaptable. , to facilitate debugging and normal operation.
(4). Since the sludge has a regeneration process and can maintain a high concentration, the sludge not only has good properties, is easy to dehydrate and dry, but also has a low sludge production rate.
(5). SBR not only has large biomass, but also is quite rich in organisms, so it has good denitrification ability.
(6). Due to the short process and less equipment, the secondary sedimentation tank, mud scraper and connecting pipelines are eliminated, so infrastructure investment is saved
3. Treatment process flow chart :
(3) Overview of Yonghe Sewage Treatment Plant:
1. Overview of the plant area:
Yonghe Sewage Treatment Plant is located in Yonghe Economic Zone, Guangzhou Economic and Technological Development Zone ( Taiwanese Investment Zone) Beside Yongshun Avenue, the sewage treatment capacity of the first phase of the project is 2,000 tons/day. It mainly uses an integrated sewage treatment device with the biological contact oxidation process (biofilm method) as the core, supplemented by a coarse and fine grid machine. , grit chamber and other pre-treatment facilities to treat sewage mainly industrial wastewater in Yonghe Economic Zone. The second phase of the project is currently under construction. The second phase of the project uses a flexible biochemical sewage treatment system with a daily sewage treatment capacity of 6,000 tons.
2. Treatment process
Biofilm method and activated sludge method are both aerobic biological treatment methods. However, the activated sludge method relies on suspended and flowing activated sludge in the aeration tank to remove organic matter, while the biofilm method relies on microorganisms fixed on the surface of the solid medium to remove organic matter, so this method is also called biological filtration. Law.
The biofilm method has the following characteristics: microorganisms fixed on the solid surface have strong adaptability to changes in wastewater quality and quantity; compared with the activated sludge method, management is more convenient; because the microorganisms Fixed on the surface of the solid medium, even microorganisms with a slow proliferation rate can live, thus forming a stable ecosystem; the more microorganisms at high trophic levels, the less sludge will naturally occur. It is generally believed that the biological filtration method has less residual sludge than the activated sludge method.
Of course, because it is difficult to control the amount of microorganisms fixed on the surface of the solid medium, it has poor flexibility in operation; and because the surface area of ??the filter material is small and the BOD volume load is limited, the spatial effect is poor; in addition, the use of natural Ventilation and supply often form an anaerobic layer in the inner layer of the biofilm, thereby reducing the effective volume with purification function. However, due to the successful development of new processes and new filter materials, the biofilm method is still widely used as a good aerobic biological treatment technology.
Biofilm methods are divided into the following three categories:
(1). Wall-moistening biofilm method. Wastewater and air flow along the biofilm on the surface of fixed or rotating contact media, such as biological filters and biological turntables.
(2). Submerged biofilm method. The contact filter material is fixed in the aeration tank, completely submerged in water, and is aerated by blast, such as contact oxidation method.
(3). Fluid bed biofilm method. The small particle size contact media such as activated carbon and sand with biofilm attached are suspended and flowed in the aeration tank.
3. Treatment process flow:
The following figure is a schematic diagram of the process flow of the first phase of Yonghe Sewage Treatment Plant:
The designed inlet and outlet of Yonghe Sewage Treatment Plant Comparison of water quality and actual conditions.
Project
Designed water inlet (mg/L)
Designed water output (mg/L)
Actual water inlet range
p>
BOD5
180
30
15~40
COD
300
80
60~140
SS
250
70
50~150
Grease
30
10
Not tested
3. Internship summary:
This internship at the Huangpu Development Zone Sewage Treatment Plant enabled me to learn the treatment process of the activated sludge process in depth as a student. The activated sludge process is an aerobic biochemical treatment commonly used to treat urban and industrial sewage. technology. Its process flow is relatively simple, the treatment cost is low, the treatment effect is good, and the BOD/COD removal rate is high, so it can be widely favored. With the improvement of process technology, the sequential batch activated sludge process (SBR) has become more and more popular. More and more attention and application have been paid to it. The SBR method has high requirements for electrification and automation, and has extraordinary treatment efficiency and the ability to treat refractory biochemical sewage, which greatly saves labor and land area. It is a relatively advanced and promising treatment technology.
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Nanjing Chengbei Urban Sewage Treatment Plant is the first sewage treatment plant in my country that treats and discharges odor, and is currently the largest covered sewage treatment plant in the country. The plant is located next to the approach bridge of the Nanjing Yangtze River Bridge in Fangjiaying, Xiaguan, Nanjing City. It covers an area of ??about 14 hectares and adopts an integrated activated sludge treatment process. Key equipment is imported from abroad. The service area of ??the sewage treatment plant is 38 square kilometers, with a planned service population of 760,000. The designed scale is to treat 300,000 cubic meters of sewage per day. According to reports, when the State Planning Commission approved the construction in September 2000, it took into account that the sewage treatment plant was close to the Yangtze River Bridge and that nearby factories, schools and residential areas were densely populated. Therefore, it was decided to take certain engineering measures to deal with the odor generated by the structure and remove it. After capping and collection, it will be chemically absorbed and treated in the deodorization workshop. It mainly receives domestic sewage and industrial wastewater from the Jinchuan River waters in the city. The service area is 38 square kilometers, with a daily sewage treatment capacity of 300,000 tons. The total investment is approximately 1.03 billion yuan. .
Nanjing Chengbei Sewage Treatment Plant is invested and constructed by Nanjing Public Water Company. The company is the first water company in the country established according to the market-oriented model. It has undertaken projects including the Jinchuan River Environmental Comprehensive Improvement Project, Nanjing Chengbei Sewage Treatment system engineering, Chengdong sewage treatment plant engineering, etc. According to the plan, after all these projects are completed, Nanjing's daily sewage treatment capacity will reach 1.29 million tons, and the urban sewage treatment rate will reach 85, which is close to the level of developed countries. "Yu Houqin, general manager of Nanjing Public Water Co., Ltd. said.
At the "Nanjing Major Project Negotiation Meeting" held in 2003, more than 70 merchants received the transfer project of operating rights of the Chengbei Sewage Treatment Plant After screening, 5 investment entities were shortlisted. In the end, China Environmental Protection Water Investment Co., Ltd. has obtained the Chengbei Sewage Treatment Plant Equity Transfer Project through TOT.
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