1.Principle of hollow ultrafiltration membrane water purification technology

Under the action of water pressure,water molecules and small molecules are forced to pass through the ultrafiltration membrane,while suspended particles,colloids,microorganisms,etc.in the water are blocked on the surface of the hollow ultrafiltration membrane.Due to the very small pores on the ultrafiltration membrane,it can effectively filter out various suspended particles,colloids,bacteria,and macromolecular organic substances in water.

2.Technical process

(1)Preprocessing

To avoid blockage of foreign objects inside the hollow ultrafiltration membrane,sand filtration and precision filter filtration methods are generally used for pre-treatment.But the system has also set up a form of direct filtering without pre-processing,in which case all you need to do is switch the relevant valves.

Well water→Storage tank-Sand filtration device→Precision filtration→Hollow ultrafiltration membrane filtration device(adding NaC10)-Temporary storage tank for purified water-Supply of purified water

(2)Filtering mode

This system has added conventional filtration and cross flow filtration.

Conventional filtration method:conventional filtration→forward flushing→backwashing→forward flushing

Chemical cleaning is manually carried out while the device is in a paused state.

Cross flow filtration method:cross flow filtration→forward flushing→backwashing→forward flushing

Chemical cleaning is manually carried out while the device is in a paused state.

The difference between conventional filtration and cross flow filtration is whether the concentrated water discharge valve is opened or not,while others are the same.

The opening delay time of the electric valve during the switching of various projects is adjustable from 10 to 40 seconds.

When the raw water is pretreated,full filtration(conventional filtration)is directly used;When the raw water is not pre treated,especially when it is turbid(turbidity greater than 20NTU),cross flow filtration is required.

Water is the source of life,and the quality of water directly affects people's physical health.Therefore,water treatment is very important.Pre treatment is an indispensable step in the water treatment process.The filtration during the pre-treatment process,especially the application of full filtration and cross flow filtration,is a topic worth exploring in the water treatment process.

Full filtration,also known as conventional filtration,is a directly selected filtering method.This method has stable effects,large processing capacity,and relatively high processing efficiency.It is a filtration method that can thoroughly filter out impurities in water.In the pre-treatment process,if the turbidity of the water is low,using full filtration is a more suitable choice.

However,for situations with high turbidity of raw water,there are some issues with using full filtration.At this point,we need to use cross flow filtering.Cross flow filtration is a flow state filtration method that uses different physical principles to deeply screen,adsorb,and intercept impurities in water in the filtration layer.

Cross flow filtration can ensure the quality of water treatment while adopting higher treatment efficiency,effectively removing harmful substances such as sediment,bacteria,and viruses from water,creating more pure water quality and achieving higher water purification effects.

The correct selection of full filtration and cross flow filtration techniques is crucial in the preprocessing process.The use of two technologies needs to be selected based on the specific situation of water quality,which can not only save costs but also improve the purification effect of water.After using the correct pre-treatment technology,the further water treatment process will be more stable,ensuring excellent water quality and better meeting people's drinking and production needs.

(3)Physical cleaning

The device is equipped with physical cleaning during operation,which lasts for 2 minutes every 58 minutes of operation.This includes 30 seconds of forward flushing,60 seconds of reverse flushing,and another 30 seconds of forward flushing.

Investment cost:around 120000 yuan(taking 100 tons of water purified and treated every day as an example);

Land area:about 30 square meters;

Operation and maintenance costs:The daily operating cost per ton of water is approximately 0.7 yuan;

Equipment service life:generally 5-10 years,with a hollow ultrafiltration membrane service life of 3-5 years;

3.Main facilities and equipment

1.Well water storage tank:temporarily storing raw water for filtration,with a water level float installed in the tank to control the replenishment of incoming water and the operation of the purification system's raw water pump.

(2)Sand filtration device:Pre filter large impurities such as sediment in the raw water to reduce the filtration pressure of the hollow ultrafiltration membrane.

(3)Precision filtration system:Ensure that the leaked sand in the sand filter tank does not enter the hollow ultrafiltration membrane.

(4)Hollow fiber ultrafiltration membrane filtration device:a filtration device made of hollow fiber ultrafiltration membrane components,achieving deep purification of well water,removing rust and most impurities,and reducing turbidity.

(5)Chlorination disinfection:Inject sodium hypochlorite into the production water pipeline to ensure that the bacterial indicators meet the requirements of the national standard for drinking water.

(6)Temporary storage tank for purified water:It temporarily stores treated purified water,and is equipped with a water level electrode inside the tank to indicate whether water is automatically added to the tank and whether water is sent out.

4.Technical advantages

The hollow ultrafiltration membrane water purification device has multiple purification capabilities,improving the functions of inlet pretreatment,water storage,backwashing of the membrane,automatic sewage discharge,and monitoring of equipment operation status.This treatment device has made significant breakthroughs in the integration,scalability,safety and stability,and standardization of water purification systems through scientific and reasonable design.It has advantages such as high filtration accuracy,large permeability,long service life,and low operating costs.The cost of water purification per ton is about 0.7 yuan,which is suitable for many urban and rural water treatment needs.