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Q The designed membrane system produces 10 cubic meters of water per hour. At the beginning of operation, the membrane has a large flow rate of 20 cubic meters per hour. After a few days of use, the flow rate gradually decreases. Now the flow rate is only fiveorsix cubic meters per hour, and there are
A The MBR membrane system must operate according to the constant flux, and the actual operation must not exceed the design unit hour water flow. Because the membrane flux is a range value, the higher the negative pressure is, the greater the high-yield water flow will be when the new membrane is running, which can be much higher than the design value. However, the short-term overload operation will cause membrane fouling, and the flux will decay rapidly, and even cause irreversible fouling. Therefore, it is necessary to strictly control the hourly water yield within the design range during operation. It is better to keep the water production for 24 hours and control the water production below the design value to ensure the long-term stable operation of the membrane.
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Q After the diaphragm is damaged, the sludge enters the diaphragm to collect water to other diaphragms. What should be done?
A If there is an impact on the effluent quality or the hardening is serious, it needs to be replaced in time. If there is no impact, it is recommended to pump the sludge for a period of time to dilute and discharge it gradually.
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Q If the amount of sludge cannot be cultivated during operation, I need to add nutrients. How to calculate this amount?
A Add according to the amount of carbon (BOD) nitrogen and phosphorus 100:5:1. According to the volume of the biochemical tank, the dosage keeps the BOD concentration at 200mg/l. It is recommended to add glucose, urea and sodium dihydrogen phosphate.
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Q What to do if there is a large amount of foam in the membrane tank during operation?
A There are two ways to deal with foam. One is to take physical spraying measures. The other is to add defoamers. Note that the defoamers added are degradable alcohol based defoamers. Silicon defoamers must not be added.
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Q What is the general reason, concentration and dosage of membrane cleaning?
A Sodium hypochlorite (3000-5000mg/l) and sodium hydroxide (500-1000mg/l) are used for organic pollution, and citric acid (3000-5000mg/l), oxalic acid (3000-5000mg/l) or hydrochloric acid (2000-3000mg/l) are used for inorganic cleaning. The dosing amount is calculated according to the membrane model and the number of pieces. The membrane element is 3l/ piece for 0.8 and 4l/ piece for 1.0. 1.5 5l/ piece.
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Q Too much aeration in the membrane tank leads to loose sludge and poor sedimentation. What is a good solution?
A According to the actual sludge concentration and aeration volume, the water quality with low pollutant concentration can appropriately reduce the aeration volume to reduce the dissolved oxygen in the membrane tank; Increase the sludge concentration in the membrane tank.
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Q How does MBR effluent have chromaticity?
A The removal rate of MBR membrane for chromaticity is limited, and it is basically not removed. Therefore, the color of the water in the membrane pool is basically the color of the effluent.
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Q What data does the MBR system need to record during operation?
A Water production flow, transmembrane pressure difference, aeration state (whether uniform), activated sludge concentration, activated sludge color and odor, activated sludge sedimentation ratio (SV30), dissolved oxygen, pH and water temperature.
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Q How to solve the turbid effluent of membrane system?
A (1) if the membrane element or silicone hose is damaged, seal the water producing silicone hose of the membrane element. (emergency treatment guaranteed water quality).
(2) Check and repair the leakage of the water production pipeline.
(3) Bacteria multiply at the water production side. Inject sodium hypochlorite with effective chlorine of 100-200mg/l into the water production pipeline for cleaning.
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Q Why does the water yield fail to reach the design value?
A Answer: (1) the membrane flux is too large to meet the long-term stable water production.
(2) The membrane is dirty and blocked, which requires troubleshooting or cleaning and maintenance.
(3) The diameter of the produced water pipeline shall meet the design requirements, and the flow rate of the main pipe is generally 0.8-1.0m/s.
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Q Why does the aeration volume fail to reach the standard value?
A The blower is faulty. Check the blower.
If the aeration pipe is blocked, open the air dispersion pipe and clean the aeration pipe.
The diameter of the main pipe of the air duct must meet the requirements, and the flow rate of the main pipe is generally 10-15m/s.
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Q Does the membrane module vent line need to be opened every day?
A It can be adjusted according to the aeration effect. Open the air dispersion pipeline for at least 3-5 minutes a week to clean the aeration pipeline. This process requires stopping the operation of the suction pump.
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Q What is the reason for the large number of bubbles when the flowmeter is running?
A Answer: (1) membrane pollution intensifies. Check the vacuum pressure gauge. If the transmembrane differential pressure rises, clean the membrane components.
(2) Check whether there is any leakage in the suction pipeline. If there is any leakage, reinstall it to eliminate the leakage point.
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Q What are the methods for cleaning the membrane? What should I do? What are the requirements for maintenance management? Will sodium hypochlorite permeate into the membrane tank? Will it affect the bacteria in the membrane tank?
A Answer: (1) Three types: online cleaning, offline cleaning and offline physical cleaning.
(2) The on-line cleaning is in the on-line high-level gravity dosing self flow diaphragm. Please refer to our design and maintenance manual for details.
(3) Yes, the impact will not be great. After dilution, the concentration of sodium hypochlorite is very low, which has little impact on the biological bacteria in the membrane tank and will lead to the death of a small number of biological bacteria.
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Q There are too few microorganisms in the biological pool here. How to solve it? Should I buy biological bacteria to cultivate by myself or buy activated sludge from municipal sewage plant to add directly?
A It is suggested to directly add the activated sludge from the sewage plant, which can be sludge from the sludge thickener or sludge after pressure filtration. The culture cycle of purchased strains is long.
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Q How to deal with algae adhering to the wall of the flowmeter?
A The pipeline can be cleaned by adding 100mg/l sodium hypochlorite. The daily flowmeter needs to be protected from light.
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Q Does the membrane tank reflux pump need to operate for 24 hours? What is the operating cycle?
A The normal reflux pump needs to operate for 24 hours. The purpose of reflux is mainly denitrification and denitrification. The startup / shutdown time ratio and reflux ratio can also be determined according to the process. (low liquid level without reflux)
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Q Does the membrane module need 24-hour aeration for operation in sewage?
A The fan is required to aerate for 24 hours during normal operation of the system. When the system does not produce water, the fan can be set to intermittent aeration (aeration for 30 minutes, stop for 3 hours) to ensure the sludge activity of the membrane tank.
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Q If calcium and magnesium ions in the membrane pool are found to be on the high side, what should be the best treatment?
A If calcium and magnesium ions are too high, pretreatment should be carried out to control them within the operating range of the membrane module, and the hardness should not exceed 350mg/l. Otherwise, scaling on the membrane surface will be caused by long-term accumulation. Once scaling is required, pickling should be carried out, and hydrochloric acid cleaning should be carried out if necessary.
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Q How to ensure the flux of membrane during low temperature operation in winter?
A Temperature has little effect on membrane flux, but low temperature will affect the activity and viscosity of sludge, thus indirectly affecting membrane flux. If conditions permit, reduce the water yield of membrane in winter, so as to delay the membrane fouling cycle.
