Con-Serv Manufacturing
Ultra Filtration
Skip to 6 GPM UF Operatimg Manual                                                        Skip to UF Product Cut Sheets


                           

Ultra filtration is a low-pressure membrane process, capable of removing colloidal materials, fine suspensions, bacteria, virus, suspended solids and large molecular weight organic materials depending on the Molecular Weight cutoff of the membrane. UltraFiltration technology is one of the fastest growing technologies in the water treatment industry.  Membrane systems have been used for many years to clean water for reuse in hundreds of industrial applications.

Membrane filtration provides a physical barrier to separate and concentrate suspended solids, oils, greases, waxes, and odor causing biological contaminants. The water produced from the system is so clean that it can be combined with reverse osmosis systems to produce drinking quality water. Ultra Filtration can provide water quality of .01 micron — small enough to remove almost all bacteria, viruses, and suspended solids. Ultrafiltration is a pressure-driven purification process in which water and low molecular weight substances permeate a membrane while particles, colloids, and macromolecules are filtered. The primary removal mechanism is size exclusion. The clean water produced from the system can be re-used or blended with other sources of water in industrial and commercial applications reducing water and sewer costs for many industries.

and concentrate suspended solids, oils, greases, waxes, and odor causing biological contaminants. The water produced from the system is so clean that it can be combined with reverse osmosis systems to produce drinking quality water. Ultra Filtration can provide water quality of .01 micron — small enough to remove almost all bacteria, viruses, and suspended solids. Ultrafiltration is a pressure-driven purification process in which water and low molecular weight substances permeate a membrane while particles, colloids, and macromolecules are filtered. The primary removal mechanism is size exclusion. The clean water produced from the system can be re-used or blended with other sources of water in industrial and commercial applications reducing water and sewer costs for many industries.

 

 

 

 

  If you look at the chart (figure 1) below provided by Koch Membrane Systems you will see the different types of Separation processes and note the specific Micron/Molecular weight cut- off of Ultra- Filtration technology. Depending on the water quality required/desired Ultra-Filtration provides the leap from waste or other process waters to high quality or high purity water.

       Figure 1

    


Ultra Filtration Membranes


Ultra–Filtration Membranes come in many different shapes/sizes, and are constructed from different types of material. The most important factor in taking advantage of Ultrafiltration technology is having a good water analysis to understand which type of membrane to use. Most installations even start with a small pilot system to verify the effectiveness of the equipment prior to full scale introduction. Most installations whether desalination or process water have a fairly consistent contaminant level, some process water like carwash reclaim can have a variety of contaminants or constituents introduced to the water that can have an impact on operation. (upsets)

 

Fortunately the technology has advanced over the years with the different types available. Membranes manufactured using PVDF or Ceramic material have a higher degree of tolerance to these upsets. Additional technological advancements have improved output and reduced capital costs. Ultrafiltration membranes function at lower pressures (5 – 150 psi) which minimizes construction cost and operating costs.

An example of one type of UF membrane is shown in Figure 2. This is the typical construction of a PVDF Hollow fiber membrane. Hollow fiber membranes can operate two ways. “Outside in” which refers to the flow of the water from the outside of the fibers having the filtering process flow to the center of the fibers., “Inside out” refers to the water flowing inside the fibers and filtering out. 

   

                  Figure 2 Typical construction of a PVDF Hollow fiber membrane

                             

 
Ultra Filtration System Design 

UltraFiltration System Manufacturers understand most applications are custom designed to solve the many different types of problem water. As mentioned earlier the better the information available through a water analysis, the better the chance of an optimized solution for each project. A short pilot study placing a smaller version of the equipment on site allows for a good design prior to design of a full scale system Pilot studies can last a day, week, or more depending upon the circumstances. When you consider the typical return on investment, permitting, regulations, and environmental impact advantages of UF, a pilot study and good water analysis can eliminate cost and headaches. Optimized Design, Operation, and chemical costs (if required) can all be calculated with this data.

Figure 3 shows a typical design of an Ultrafiltration System. It must be stressed that UF Flow diagrams may differ between each project and this is only one example. Designs will vary depending on the requirements and problems to be treated. The plumbing in/out of a UF System usually consists of a raw water inlet, filtered water outlet and drain line. Nothing has a greater effect on the performance of any membrane-based filtration system than the feed water quality. For lasting performance it is important to supply the UF systems with the feed water quality shown below in Table A.


                           
Figure 3          Typical Flow Diagram for an Ultra filtration system

            

                              

                           
Table A – Recommended Feed Water Characteristics

    

PH                                 2 - 11                                     

TDS                               up to 10,000 mg/L

TSS                               up to 500 mg/L

Temperature                  15 to 35 C

Hardness                       < 300 ppm as CaCO3

Turbidity                        < 50 NTU                               

Iron                               < 5 mg/L

Oils and Greases           < 0.1 mg/L

Solvents, phenols           < 0.1 mg/L


Ultra Filtration Applications

Briefly outlined below are a few applications that benefit from Ultra filtration:


Pretreatment of reverse osmosis and nanofiltration
Of all the pretreatment methods, the use of UF membrane is the most important step forward prior to reverse osmosis and nanofiltration. A good pretreatment will provide good quality feed water for subsequent RO and NF, and UF does just that through a consistent pore size membrane barrier that greatly surpasses the feed water quality requirement for RO and NF. The result is consistent and excellent feed water.

Municipal water treatment

The world is experiencing fresh water scarcity like never before from population growth, rapid industrial expansion, global warming and weather change, and contamination. Large UF membrane modules to drive down the cost of municipal water treatment to treat more water. UF systems require minimal added chemicals and often reduce the need for chlorine and other biological disinfectants. Packaged UF systems can be low cost solutions for small residential area or communities trying to cope with new drinking water regulations for surface water supplies. UF membranes have been shown to be a more practical and cost effective alternatives to conventional chemical and physical based water and wastewater treatment, involving coagulation, flocculation, clarification, and media filtration.

Residential and commercial water treatment

Residential water quality fluctuates depend on age of water pipes and type of water source. It can be affected by sediment, cloudiness, viruses, pathogens, cysts, rust and sand. Bacterias with typical length 0.4-14 micron to width of 0.2-2 micron can be safely removed using UF membrane in addition to viruses, pathogens, cysts and other micro-organisms. The result is clear water free of sediment and micro-organisms that cause people to get sick. There are also some commonly found water-borne parasites with tough walls that are chlorine resistant. The use of UV disinfection is not enough while UF membrane provides a safe barrier to keep out these harmful micro-organisms.

                      
                            (a) Crytosporidium                             (b) Giardia Lamblia

Desalination and ocean depth water filtration

During the process of making drinking water from brackish saline water or seawater, a combination of ultrafiltration followed by reverse osmosis can be very cost effective. The UF membranes by MST used as pretreatment can significantly extend the useful life of RO elements due to the removals of organisms and suspended matters in feed water. When treating brackish water with relatively low TDS, UF can be used as pretreatment to a reverse osmosis system, and also to produce permeate for blending with RO product. The result is water for distribution that not only tastes good but is less expensive to produce. The UF approach allows the designer to significantly reduce the size of the RO system and its overall costs.

Wastewater recovery and re-use

With ever more stringent environmental laws today, recovering and reusing your process water as a renewable water source is becoming more important across many industries. UF can help you reuse water from the process wastewater, rinsing operations, and low-solid effluents with water recoveries up to 95% of the volume of wastewater that would otherwise be lost through discharge. Wastewater is economically recycled using advanced PVDF ultrafiltration membrane systems in combination with RO systems. With advanced water recovery technologies, you can gain value from your process, reduce wastewater discharges, and improve your operations.

Warranty:

A Typical warranty for UF membranes is shown below. As is any warranty, the following defines the manufacturers concerns with the use of this technology and what they have determined might affect the performance and life of the membrane.  

 UF Membrane Module Quality Warranty

Con-Serv Manufacturing (herein referred to as the "Seller") provides the following warranty for systems designed with UF membranes.

1.   Material and Workmanship Warranty

If the buyer uses and maintains the membrane modules properly in accordance with the membrane module manufacturer's standard technical recommendations, any defects in materials or workmanship, will be repaired or replaced by the Seller, effective as of the date the modules arrive at the customer's designated location.

2.   Performance Warranty

Effective the date of receipt of the membrane modules by the Buyer, the membrane modules are covered under the Seller’s for 3-year Pro-Rated Performance Warranty.  In the first year, the Seller will replace or repair the membrane modules if they are defective. In the 2nd year, should the membranes need to be replaced, the Buyer will be required to pay 33.3% of the original sale price for the replacement membrane.  In the 3rd year, should the membranes need to be replaced, the  Buyer will be required to pay 66.6% of the original sale price for the replacement membrane.

During this 3-year warranty period, if the membrane modules are operated in accordance with the manufacturer’s recommendations, the Seller warrants that the membrane modules will not fail to meet the performance specifications of the membrane module due to cracking of the fibers, and the decline of the membrane flux will be less than 10% for every single year.

If performance problems are identified, the Buyer should notify the Seller in writing, and the Seller will reply within 24 hrs.  If the defective membranes are within a reasonable access to the Seller, the Seller will assign a technician to the jobsite to repair or replace the defective modules.  If the performance problem is due to the Buyer's failure to comply with the manufacturer’s operating recommendations, or the membrane fiber cracking is due to excessive applied pressure to the membrane modules, the performance warranty is void.

3.   Warranty Conditions

During the warranty period, the Seller warrants that the membranes will perform to specification and the warranty will be in effect only if the membrane modules are operated in accordance with the following conditions.  

If these conditions are not met the warranty is null and void, including for membrane products in the first year of the warranty period.

a)     The membrane feed water has a pH of 2-10; temperature: 5-45C; the diameter of the suspended particles is no more than 500um;and the oil and grease is = 2 mg/l;

 

b)    There are no physical or chemical substances in the feed water capable of damaging the membrane. (Refer to the Seller’s specification "Membrane Module Chemical Compatibility List").

 

c)     During membrane operation, the maximum applied membrane pressure is =0.15Mpa (22 psi).

 

d)    During normal operation, should the membrane flux decline 10-20%, or the membranes are obviously scaled, the Buyer promptly cleans the membranes in accordance with the Seller’s cleaning instructions.

 

e)     If the membranes are installed in an industrial wastewater application, then the pre-treatment and the membrane operation must be confirmed to be satisfactory by the Seller.

 

f)     The membranes must not be exposed to feed water containing substances which obviously and consistently foul the membranes.

 

g)    Before installation, the membrane modules should be stored in the original packaging, in the shade and away from direct sunshine, at an ambient temperature of 5 - 35C.

 

h)     After the membrane modules have been used, they must not be allowed to become dehydrated. If the membranes transition from wet to dry, the structure of the membrane will be altered, resulting in a permanent flux decline.

 

i)      The membranes must not be allowed to freeze.

 

j)      The system design and the application of the specific membrane model must be in accordance with the manufacturer’s recommendations.

 

k)     The personnel operating and maintaining the system in which the membranes are installed, should have a full knowledge of the system performance.  Before operation, the operating personnel should have the necessary training, and have knowledge of the maintenance and operation procedures, and troubleshooting.

 

l)      The Buyer should maintain a system operation record, and verify the accuracy, completeness, and consistency of the data.

 

m)   If replacement or the repair of the modules is required, the Buyer must submit the request in writing, including an explanation of the performance problems, the date of purchase, and specify the membrane model and serial number.  The defective and conforming membranes must continue to be stored properly until replaced.