Surface water treatment process
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Our factory originally used groundwater, which was processed through sand filtration, safety filters, reverse osmosis, and ion exchange to supply secondary deionized water to the boilers. Now that Yellow River water is being used, the flux of the reverse osmosis membranes has dropped sharply, and the existing process is no longer suitable for treating surface water. I would like to ask the experts: what additional processes and equipment are needed for the treatment of surface water? Quality of surface water near the surface: pH value of 7.9, chloride content of 255 mg/L, conductivity of 1250 μs/cm, calcium ions at 45 mg/L, total alkalinity of 2.5 mmol/L, turbidity of 11 NTU, and suspended solids at 10 mg/L. Groundwater quality: pH value of 8.5, chloride content of 510 mg/L, conductivity of 1800 μs/cm, calcium ions at 9 mg/L, total alkalinity of 4.19 mmol/L, and turbidity of 2 NTU.
Add coagulation and sedimentation, followed by sand filtration and safety filters, add microfiltration, and then reverse osmosis and ion exchange.
In the coagulation and sedimentation step, is it that the coagulant (PAC) is added to the water through a pipeline mixer, and then sedimentation takes place in a sedimentation tank, with the supernatant being sent to the next stage? How is the PAC filling amount controlled? Are there any methods to determine whether the PAC dosage is sufficient? Also, regarding the quality of this surface water, which type of sedimentation tank do you think would be better to use?
Now, the concentrated water passes through another set of reverse osmosis units and is reused in the circulating water system.
Dear, the water used for the boiler certainly needs to be free from scaling, right? Can’t it be solved using ion exchange and reverse osmosis either? Is your boiler a steam boiler?
Now the flux of the reverse osmosis unit is decreasing while the pressure difference is increasing. The quality of the water supplied is fine.
I can help you with that. I work in the field of high-voltage electrostatic water treatment technology. Please take a look at this paper first: http://www.docin.com/p-1173828629.html
Based on surface water and groundwater data, turbidity is the main cause of fouling in RO membranes; as a precaution, installing an ultrafiltration unit after sand filtration will suffice； After ultrafiltration, ensuring that the turbidity of the water fed to the reverse osmosis membrane is less than 0.1 and SDI is less than 3 will basically guarantee the continuous and stable operation of the membrane. With surface water turbidity of only 11 NTU, coagulation-precipitation followed by sand filtration may not yield good results; moreover, the quality of water in the Yellow River deteriorates seasonally, which can lead to higher turbidity at certain times. The conventional coagulation-sedimentation treatment involves adding PAC or PAM in the coagulation mixing area, followed by the removal of suspended solids through sedimentation. The sedimentation tanks commonly used, which offer good performance, are inclined tube sedimentation tanks or inclined plate sedimentation tanks. Their main advantages are low space requirement, effective sedimentation, and easy collection and handling of the sediment. The amount of PAC or PAM to be added is usually determined through pilot tests on-site.