Membrane technologies have emerged in the last 2-3 decades as viable and cost effective treatment alternatives for difficult to treat water supplies, desalination, as well as enabling compliance with more stringent drinking water regulations. Primary reasons for these technologies becoming more appealing include:
-
They provide a barrier against microbes and pathogens
-
They are highly effective solutions to Disinfection By-Products
-
They use fewer treatment unit processes and chemicals
-
They have gained significant improved efficiencies at reduced costs in recent decades
-
They provide an opportunity to tap into new sources of supplies previously considered “unusable”
-
They are applicable to a broad range of water quality concerns with their multi-contaminant rejection capabilities
Reverse Osmosis (RO) treatment systems have long been regarded as one of the most effective and reliable means of removing impurities from water. RO, also called hyper-filtration, is capable of the highest filtration possible, including separation of dissolved salts and ions. Reverse Osmosis (RO) membrane technology has been successfully used since 1970’s for brackish and seawater desalination. RO systems are also utilized for removal of inorganic contaminants such as radio-nuclides, nitrates, arsenic, pesticides and other contaminants.
A lower pressure RO technology called nanofiltration (NF), also known as “membrane softening,” has also been widely used for treatment of hard, high color, and high organic content feed water.
A non-pressure, electric potential driven membrane called Electro Dialysis Reversal (EDR) has also been widely used for removal of dissolved substances and contaminants.
During the past two decades, utilities worldwide have turned to low pressure membrane filtration to meet more stringent water quality requirements. Low pressure microfiltration (MF) and ultrafiltration (UF) membrane filtration technologies have emerged as viable options for addressing the current and future drinking water regulations related to the treatment of surface water, groundwater under the influence, and water reuse applications for microbial and turbidity removal.
MF and UF are considered feasible treatment alternatives to conventional granular media processes. Both systems have been shown to exceed the removal efficiencies identified in the Surface Water Treatment Rule such as Cryptosporidium oocyst, Giardia cyst, and turbidity.
Membrane Bioreactor (MBR) and tertiary treatment systems are the best available technologies for communities concerned with protecting the environment and preserving potable water supplies. Whether a community needs to improve the effluent quality from its existing conventional wastewater treatment plant, or construct a new compact and highly efficient wastewater treatment system, MBRs provide cost-effective solutions that will meet or exceed discharge standards for years to come. Effluent from these systems is of such high quality that it can be safely discharged into the most sensitive aquatic environments or reused in irrigation, industrial processes, or groundwater recharge.
Selecting the Right Membrane
Selecting the right membrane process is very critical to long-term performance and project success. Some of these membranes are not chlorine or oxidant tolerant. Depending on the raw water chemistry, there is a potential for scaling and fouling, which significantly reduces the life of the membrane and increases power requirements and membrane replacement costs. These are the biggest challenge of membranes and should be carefully considered.
There are several well-qualified membrane manufacturers in the U.S., each with their own unique requirements. It is important to have a complete understanding of these unique requirements and system capabilities as well as their limitations for a successful membrane project implementation with the client and end user in mind. These critical decisions cannot be made by the manufacturers nor published “text book” guidelines. Unlike some engineering firms who may have only worked with one or two types of membranes, our team is very familiar and has hands-on experience with all the leading manufacturers of both MF/UF as well as NF/RO systems. WATEK if very familiar and has hands on experience with all the leading membrane and system manufacturers: Dow, Evoqua (Memcor), GE (Zenon), Hydranautics, Koch, Kruger, Nano-H2O, Norit (X-Flow), Ovivo, Osmonics, Pall Corporation and Toray. Although the membrane manufacturers are capable of recommending an applicable membrane configuration, the engineer should provide a custom design and coordination of the entire treatment system. This includes the membrane modules/skids/cells, feed pumps, chemical feed systems, pretreatment systems, energy recovery devices, cleaning systems, and instrumentation and control systems. A knowledgeable design engineer serves as a single source of contact, responsible for coordinating all these systems and various individual components required in a treatment plant. This coordination is crucial to the compatibility of all related systems and the smooth implementation of the project.
Selecting the Right Membrane System Engineer
One of the most important decisions made in membrane projects is selection of the Membrane System Engineer to ensure all critical membrane selection, design, performance, coordination between various disciplines, as well as energy and cost optimization parameters are diligently considered for a smooth implementation of the membrane system project.
WATEK specializes in the application of membrane technologies and has been involved in some of the world’s largest and most complex membrane plants. WATEK’s President, Mr. Movahed is the past President and current member of the American Membrane Technology Association (AMTA) Board of Directors. He has reviewed and edited the Ten State Standard Policies for Microfiltration-Ultrafiltration (MF/UF) and Nanofiltration-Reverse Osmosis (NF/RO) and has been in direct communication with EPA staff, as well as numerous state regulatory agencies through his activities as the chair of AMTA Government Affairs and Publication Committee.
WATEK is prepared to assist our clients with all types of membrane projects. In addition to our full time staff, we have established an excellent history of strong partnerships and outstanding performance with several large and small engineering firms who provide the necessary architectural, structural, electrical, and mechanical engineering services needed in support of any size membrane project. Our efficient and focused approach, combined with our low overhead rates, enables us to provide exceptionally high quality membrane engineering services with unprecedented proficient costs.
Our vast wealth of knowledge and experience in membrane facility design, both nationally as well as internationally provides our clients with the assurance that the solutions provided by WATEK will meet and exceed foreseeable regulations and our client’s long term goals.
Being a small firm, we have multiple ongoing agreements with subconsultants who make it possible for WATEK to execute projects requiring multi-disciplinary expertise successfully.
Let WATEK engineers with extensive membrane treatment experience provide you with a cost effective, practical, and reliable solution.
One of these membrane technologies has the answer for your particular situation, with multiple full scale global applications in:
-
Drinking Water
-
Municipal Wastewater
-
Industrial Wastewater
-
Ultrapure Water
-
Recovery/Reuse
-
Agriculture
-
Landfill Leachate
-
Pharmaceutical
-
Power Generation
-
Pulp and Paper
-
Semiconductor
-
Floating Plants