Ultrafiltration water system is a method of water treatment that can completely remove suspended particles, turbidity factors, TSS and dirt in the water. In this method, Ultrafilter are used and particles that are larger than 1 nm are completely eliminated.
Ultrafiltration water system or (UF) is used in the river water treatment, wells, seawater, treated wastewater and all water sources that include turbidity, TSS as well as microorganisms (such as bacteria, viruses and parasites) and by removing about 99% of all contamination factors which are or various factors such as beverage, agricultural and industrial.
TARHOKAR Engineering company business plan is working in the field of designing, manufacturing, installing a variety of water treatment package by ultrafiltration method among internationally renowned brands such as DOW, Hydranautics, MB, Inge, Koch which being used in a variety of industries such as advanced wastewater treatment, agricultural water production, seawater treatment, drinking water, deep water wells and rivers so as to eliminate turbidity, TSS and microorganisms.
In Ultrafiltration water system package hollow membranes from the PEMS (Hollow fiber membrane) is used to purify the raw water. The diameter of the cavities on the surface of the membrane is able to remove suspended particles to a diameter of 0.02 microns; thus, 99% of the microorganisms, bacteria and suspended particles by these membranes are physically eliminated and the turbidity of the outlet water will be less than 0.1 NTU.
In Ultrafiltration water system, raw water has high turbidity and through feed pump entered into the pretreatment. In pretreatment, coarse particles are about 100 ~ 150 μm or larger and separated from the water. Then the water enters Ultrafiltration (UF) and larger particles of 1nm which are the constitutive factors of turbidity, TSS and microorganisms that completely remained on the ultrafiltration water system. After about 1 hour (or less), ultrafiltration water system requires backwash. As it has been said, all suspended particles remain on the UF.
The backwash and CEB cycle depends directly on the amount of water turbidity. In the process of backwash, the following steps are done:
1. Internal ultrafiltration aeration (UF) and unloading compartments
2. Washing and backwash for disinfecting with disinfectants (such as chlorine)
3. Rinsing and CEB with chemicals (according to water analysis) to prevent sedimentation.
4. Preparation for reusing ultrafiltration by raw water
In addition to the above, cleaning in place system (CIP) is used periodically to prevent sedimentation and saturation of suspended solids and solutions.
All manufacturers of ultrafiltration membranes have provided the maximum turbidity, TSS, and also the COD inputs to such water purification devices so that when designing a ultrafiltration unit, the designer of these units should be taken into consideration.
1. The amount of turbidity is utmost 300 NTU.
2. The total chemical oxygen demand or (COD) should be less than 60 mg /lit.
3. Oil & Grease should be less than 2 mg/lit.
4. The total suspended solids (TSS) must be less than 100 mg / lit.
5. Permissible limits for pH should be between 2 and 11 units.
The oil & grease and COD permitted entry to ultrafiltration system must be considered in the design of advanced wastewater treatment units that are designed and installed at the outlet of wastewater treatment plants.
In a water treatment package by using ultrafiltration water system, in addition to the backwash cycle and the chemical wash (CEB), it is necessary to clean in the place or (CIP). This washing lasts for 1 to 2 days and after 3 to 4 months the ultrafiltration package (UF) is performed.
The purpose of cleaning in place (CIP) of ultrafiltration package is to clear the surface of the membranes from all solute deposits that over time have been taken as a saturation layer on the membrane surface.
The steps of cleaning in place (CIP), water purification package by ultrafiltration method include washing with bases materials PH=11, then washing with pure water in the first step, next washing with acidic materials PH=2 and at the end is washing with pure water as a second stage.
As mentioned above, any package of ultrafiltration water system in a refined water cycle requires backwash and disinfection operations. For example, each ultrafiltration unit (UF) produces refined water for 45 minutes and is rinsed for 5 to 7 minutes and is ready for service in the next step. However, the efficiency of ultrafiltration unit is higher than 80%.
The control of the valves related to the inlet and outlet flows, and also the route of backwash and aeration, due to the precise timing of the production cycle and the ultrafiltration washing should be done automatically with the help of PLC.
In other words, the operator does not play any role in the process of backwash and disinfection and all of these steps are carried out by the PLC system.
The main results of using ultrafiltration (UF) package include:
1. Reduction of TSS or suspended solid particles.
2. Reduction of turbidity and water color or wastewater.
3. Removing all microbial agents, organisms, germs and viruses.
4. Reduction of bivalent ions such as calcium, magnesium and sulfate.
5. Removing of insoluble heavy metals such as iron, cobalt, zinc and nickel.
6. Reduction of chemical oxygen demand, or COD effluent or sewage.
7. Reduction of biological oxygen demand or BOD as effluent or sewage.
An ultrafiltration water system can be used in a wide range of water and wastewater industries, some of the most important features include:
1. Surface water desalination such as river water, water behind dams and water of ponds which have color, turbidity and high TSS.
2. Infected water purification to microorganisms such as effluent or water contaminated with sewage.
3. Pretreatment of reverse osmosis units (RO) especially in seawater treatment.
4. Advanced wastewater treatment and sewage outlet of biological wastewater treatment plants.
The use of water desalination package by ultrafiltration method, due to its high efficiency in removing turbidity and TSS, as well as the complete elimination of bacteria and organisms is used as a safe method in pretreatment of reverse osmosis water desalination (RO). As reverse osmosis units are highly susceptible to turbidity and microbial contamination; therefore, the use of ultrafiltration water system especially in those areas where water turbidity is high, it shows a special reassurance about the efficiency and lifetime of reverse osmosis membranes.
Another advantages of water desalination by using ultrafiltration method, is its wide application in the removal of microorganisms, bacteria and viruses at the outlet of sewage and wastewater treatment plants. Since, the use of this system reduce the chemical oxygen demand (COD) and causes to the complete elimination of organisms and increases the efficiency of agricultural irrigation by wastewater.
Today, we encounter with serious problems such as reduction in groundwater resources, decreasing annual precipitation rates and increasing population in our country Iran which lead to the water scarcity. Without doubt, one of the ways used in many countries of the world is to manage water resources in order to restore wastewater and effluent into the production cycle and reuse it.
Meantime, considering the high efficiency of ultrafiltration package in the treatment of wastewater and sewage; therefore, there is the possibility of returning water to the production cycle and it should be seriously considered.