But in order to debug the progress of the pre-process is to add sludge
The full version of the following
Commissioning methods
(a) Preparation
1. One technician each.
b. Trained personnel in place for each position, the number of people depending on the job setup and the availability of shifts.
2. Other preparatory work:
a. Collect process design drawings and design instructions, automatic control, instrumentation and equipment manuals and other related information.
b. Check whether the laboratory instruments, utensils, medicines, etc. are complete in order to carry out water quality analysis.
c. Check whether the size and elevation of each structure and its appurtenant facilities are in line with the design, and whether there is any blockage in the pipelines and structures.
d. Check whether the total power supply and each equipment power supply is normal.
e. Check whether the equipment can be started normally, and whether various gate valves can be opened and closed normally.
f. Check whether the instrumentation and control system is normal.
g. Check whether the repair and maintenance tools are complete, and whether the common wearing parts are prepared.
h.Purchase flocculant.
(B) with load test
Open the water treatment facilities, pipelines, all valves and gate valves, start the feed pump to send water, according to the water intake of each structure, along the process flow in due course to start other equipment. In this process should do the following aspects of work: First, check whether the total inlet current meets the requirements of the transformer and distribution equipment, whether the work of the various equipment is normal and can meet the design requirements, whether the instrumentation is working properly, the automatic control system can meet the design requirements. Secondly, use the volume method to check whether the inlet and outlet water, reflux and residual sludge flow meter are accurate, check all kinds of instruments, test the quality of inlet water, measure the flow rate, measure and record the voltage, current, power and speed of the equipment. Third, solve the problems found during the trial run in time. Fourth, the preparation of equipment operating procedures.
(C) activated sludge culture
The essence of activated sludge culture is to produce and accumulate a certain amount of microorganisms in the treatment system in a period of time through certain means, and its cultivation methods are mainly continuous and intermittent.
1. Continuous culture: continuous culture refers to the activated sludge culture in the case of continuous water inlet and continuous water outlet. The condition for choosing this kind of culture is to have enough water inlet, that is, the daily water inlet can at least satisfy the water quantity of a water inlet pump for 24 hours. The advantage of continuous culture is that the cultivation time is short, and the microorganisms need a short time to be domesticated. The specific operation method is based on the size of the incoming water to determine the number of water pumps and biological pools to open the number of groups, grating machine, sand sedimentation tank, the second sedimentation tank is fully open, open the external reflux pumps (if there is an internal reflux pumps, choose not to open), back to the flow rate is controlled at more than 100%, aeration zone dissolved oxygen is greater than 2mg / l, the average flow rate of biological pools is not less than 0.3m/s, the absolute flow rate is not less than 0.2m / s, continuous operation. The flow rate of the biological pool is not less than 0.2m/s. In this process, every day to do a good job in the determination of various water quality indicators and control parameters. When sv% reaches more than 10%, the activated sludge culture is successful, at this time the effluent BOD5, SS, COD and other indicators can generally meet the design requirements.
2. Intermittent cultivation: intermittent cultivation is according to the water inlet, aeration, sedimentation, skimming supernatant and so on four stages of the reciprocating cycle of the cultivation mode, is in the water inlet small can not meet the continuous operation of a cultivation mode. It is characterized by long microbial accumulation cycle, long domestication time, and large operation workload. The specific operation method is to open the water inlet pump, grating machine, sand sedimentation tank at the same time, to be full of water in the bio-pool began to aerate, while stopping the water intake, regular measurement of the bio-pool, when the COD, SS is significantly smaller than the water intake to stop the aeration, precipitation for 2 hours and then into the water, skimming at the same time, the supernatant. In this process of water quality indicators and control parameters of the determination and completion of the sign of the same continuous culture.
(D) activated sludge domestication
The purpose of domestication is to select the microorganisms adapted to the actual water quality, eliminating the useless microorganisms, for the treatment process of denitrification and removal of phosphorus, through domestication to make the nitrifying bacteria, denitrifying bacteria, polyphosphorus bacteria to become the dominant bacterial group. Specific practice is to first maintain the normal operation of the process, then, strictly control the process control parameters, DO in the anaerobic pool control below 0.1mg/l, in the anoxic pool control below 0.5mg/l, in the aerobic pool control below 2-3mg/l, aerobic pool aeration time is not less than 5 hours, the external reflux ratio of 50% to 100%, the internal reflux ratio of 200% to 300%, and, every day to remove the The residual sludge of 30%~50% of the daily sludge production was eliminated every day. During the process, the water quality indexes of inlet and outlet water are tested every day until each index of outlet water meets the design requirements.
(E) process control parameters to determine
The design of the process control parameters are predicted in the water, water quality conditions determined, and actually put into operation when the sewage plant and its water quality is often with the design of a large difference, therefore, must be based on the actual amount of water to determine the quality of water to determine the appropriate process control parameters in order to ensure that the operation of the normal operation and make the effluent water quality to meet the standards. At the same time as possible to reduce energy consumption.
1. Process parameters:
The important process parameters to be determined are the control level of the influent pump room, sand sedimentation tank sand discharge cycle, biological pool dissolved oxygen DO and redox potential ORP, sludge reflux ratio of R, the sludge concentration of MLVSS, sludge sedimentation ratio of SV%, the sludge index SVI, the age of the sludge SRT, the residual sludge discharge cycle and the daily discharge, the second sedimentation tank, the height of the mud surface, etc., which affects the quality and quality of the water. Mud surface height, etc., which affects the size of the energy consumption of the main factors are the height of the influent water level and the size of the sludge concentration MLVSS, the main factors affecting the effect of nitrogen and phosphorus removal is dissolved oxygen DO and sludge age SRT.
2. Determination of the method:
Intake of the pump room level in the influent system to ensure that the premise does not overflow to the extent possible under the premise of the water level to control in the high level of water operation. Use the volume of the daily exclusion of the sea volume compared with the volume of sand collection to determine the sand removal cycle, the volume of sand removal is less than the volume of sand collection. Bio-pool DO and ORP according to the anaerobic pool phosphorus release, anoxic pool denitrification, aerobic pool phosphorus absorption and nitrification to determine the situation, in general, anaerobic pool DO is less than 0.1mg / l, anoxic pool DO is less than 0.5mg / l, aerobic pool DO control in the 2-3mg / l between, anaerobic pool ORP is less than -250mv, anoxic pool ORP is -100mv or so, anaerobic pool ORP greater than 40mv, anoxic pool ORP is -100mv. The ORP of aerobic tank is more than 40mv. The size of reflux ratio R should be determined according to the residence time of sludge in the secondary sedimentation tank and the release of phosphorus, generally about 80% is more appropriate. The sludge concentration MLVSS is determined by the sludge loading, and the sludge loading of the nitrogen and phosphorus removal process is generally about 0.12kgBOD5/(kgMLVSS*d) which is more suitable. Sludge age SRT to consider the requirements of the design water quality, for nitrogen and phosphorus removal process, it is generally controlled in about 8 days. (F) process control program:
Process control program is mainly used to guide the production operation, is the main basis for the process operation, which mainly contains the following aspects: First, the basic situation of the structures; Second, the operation of the structures to control the parameters; Third, the operation of the facilities and equipment; Fourth, the process of adjusting the method; Fifth, the treatment facilities maintenance and repair methods. Process control procedures should be prepared after the process parameters are determined.
(VII) other work in the commissioning:
The sewage plant to run correctly, there should also be a set of perfect system, which mainly includes the management system, job responsibilities, operating procedures, operating records, equipment and facilities files, etc., in the commissioning process can be accomplished step by step the above work.
Three, should pay attention to the problem
1. through all facilities, pipelines and underwater equipment before the inspection, thoroughly clean up all sundries, in order to avoid the water after the pipeline, equipment clogging and maintenance of underwater equipment to affect the smooth progress of the commissioning. After the water for underwater facilities and equipment maintenance difficulties are quite large, mainly because the maintenance of the pool needs to be emptied, and the volume of the pool is a few thousand cubic meters small, large or tens of thousands of cubic meters, emptying a rather time-consuming and labor-intensive, especially after the activated sludge, the water to where to put the problem in itself, put out the pollution will occur, put into other pools tend to be loaded and can not be. Therefore, before the water must be carefully checked and cleaned up.
2. Strictly monitor the quality of incoming water, especially PH, more than the requirements should be immediately taken corresponding measures, otherwise it will make the cultivation of bacteria work foregone.
3. Cultivation of bacteria at the beginning of the aeration tank will appear a large number of white foam, when serious, will be piled up two or three meters high, contamination of the walkway and the site instrumentation, this problem is an inevitable phenomenon in the early stage of the cultivation of bacteria, as long as the control of the dissolved oxygen and to take appropriate anti-foaming measures can be resolved.
4. Tap water volume and pressure size is often easy to be ignored, in the commissioning process, laboratory and sludge dewatering of some instruments and equipment on the amount of water and water pressure have strict requirements, if not to meet the requirements of these instruments and equipment will not be able to use. Sewage plant is generally far from the city, at the end of the pipeline network of tap water, water volume and water pressure is usually very small, therefore, certain devices should be set to improve the water volume and water pressure.
Four recommendations
Process commissioning is related to the normal operation of the sewage treatment plant and the benefits can give full play to the important work, it has a strong technical, difficult and high characteristics, the need for knowledge of wastewater treatment and long-term operational experience of the professionals or professional organizations to implement, therefore, it is recommended that the relevant departments will be included in the process of commissioning the project and to arrange for adequate funding to ensure that commissioning The work is carried out effectively.