Types of membranes in gray water treatment plant

Membranes are an essential product for water and wastewater treatment. There are four main types of membranes, classified by membrane pore size, that are widely used for commercial purposes: microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. The four membrane types are widely used to meet the objectives of drinking water codes and water and wastewater treatment guidelines. Reverse osmosis membranes are also used to treat desalinated and ultrapure water for various industrial and other uses, such as power plants, chip manufacturing, food industry, pharmaceutical, medical, etc.

The appropriate and perhaps most reliable water purification process must be selected for a given facility based on specific operating conditions, functional characteristics, and economic variables (stock, operation, and maintenance costs). This is why a large percentage of membrane processes available on the market are variations of standard and reverse osmosis membrane technologies.

Site preparations before installing the gray water treatment plant

Some equipment must be available in the place where the establishment takes place to treat gray water, which of course varies according to the size of the plant to be implemented:

• Separate gray water drainage from black water and kitchen water. Because it contains oils (oils need separate and tedious treatment, but in car washes an oil separator must be installed).
• Collect gray water in a main tank (with another branch of drainage for wastewater used for emergencies). The tank should be located close to the treatment unit room, no more than 4 meters.
• Establish a filter on the collection tank to collect solid and large-sized materials, so that the mesh spacing does not exceed 25 mm.
• The capacity of the collection tank depends on the capacity of the required processing unit.
• Providing a tank for the produced water with a capacity appropriate to the capacity of the required treatment unit.
• Providing a source of electrical current inside the treatment room.
• Preparing a room for the processing unit whose size depends on the capacity of the station.
• Creating a network to reuse produced water, whether to siphons or to agricultural areas.

You can contact our experts to help you with essential requirements.

Division of membranes according to their geometric configuration (Geometry)

When the membrane is formed, we call it a module… and it is divided into four types according to the geometric configuration:

Spiral wound module

This is the traditional and most famous type, as these membranes are formed in the form of wide spiral panels in successive layers with supporting materials such as the “envelope”.

These panels are wrapped in a steel tube, and this solid tube is perforated. It is installed in the middle part of the pressure vessel and permeate water flows through it, as we mentioned. It is also called a Permeate collection tube.

This design helps increase the surface area in less space. Its cost is low, but it has the drawback of its sensitivity to pollution and the difficulty of maintaining it due to the way it is manufactured.

What happens is that the feed water enters spaces called the feed spacer. Then penetrates the membrane to enter through other channels called the spacer permeate channel between the layers of membranes. That the filtered water or permeate flows through spiral paths and from there to the inner tube in which the permeate water collects.

Another name given to the spacer permeate channel is the permeate water carrier. Because it carries permite water to the inner tube.

We notice the presence of supporting layers (supports) that are wrapped in a spiral with the membranes to stabilize them and protect them from changes in pressure or increased load intensity.

Hollow fine fibers module (HFRO)

It resembles hollow strands of hair on the head. It is a cover or shell that carries within it a large number of tubes or hollow fibers. Then gathered in bundles having a diameter of 0.1 to 2 millimeters. When the feed water enters through the open cores. The water penetrates the fiber wall and exits the permit in the surrounding area (not from the middle as in a spiral plate).

Because these hollow bristles do not allow turbulent flow to occur. They are more susceptible to fouling or scale formation and are difficult to clean chemically. Therefore, it is often used with seawater, as the possibility of foaming is low. Its use with brackish water is limited.

Lamellar membrane

The membranes are in the form of parallel longitudinal sheets.

Tubular membrane

This type is also used with poor-quality or viscous water. It does not require primary treatment of the feed water. It operates at very high pressures that may reach 100 bar.

From the name, we conclude that each membrane is placed in a perforated tube. These tubes are assembled like a bundle in what is called a module.