What is filter media in wastewater treatment?
Filtration of water is very important for almost all irrigation systems. Proper filtration helps extend the life of the irrigation system and improve maintenance.
Filtration is a basic requirement for drip or micro sprinkler emitters to prevent clogging. Sand grains, rust, and other materials can block micro, mini and sprinkler nozzles, leading to inadvertent dehydration of plants. Many water sources, such as reservoirs, rivers, and of course sewage, contain many organic substances such as algae and bacteria that need to be removed from drip irrigation, spray mist, and micro sprinkler systems.
If these substances are not removed, toxic debris and colonies can accumulate on emitters and other equipment. Of course, rust and sand grains are a safe platform for coating with organic materials, forming large lumps in the system and completely blocking the transmission of water.
What is a mesh Filter?
Sieve filters are probably the oldest and most widely used in irrigation systems. Excellent for removing hard particles such as rust. However, when it comes to sand, it can get caught in the strainer and quickly clog. Sieve filters are cheaper than usual.
Sensitive organic materials cross the sieve, and raw materials usually fill the top of the sieve, resulting in more frequent cleaning intervals. The usual solution for sieving filters is to increase the filtration to extend the wash interval.
Today, there are some modern solutions for self-cleaning screen filters. This is done by backwashing and/or rinsing with a sprinkler with an internal spray nozzle for cleaning. To wash the filters with clean water, you need at least two parallel filters. This allows one clean water to wash the other clean water.
A semi-automatic mesh filter can also be used to clean the filter by turning a manual crank or a round brush that turns inside the nozzle. Without an automatic self-cleaning mechanism, we do not recommend using a mesh filter if the water contains organic matter.
Clogged material on the sieve can create large pressure differences that can cause the sieve to collapse, reduce the flow of irrigation water, or even stop altogether. The sieve filter is cleaned by removing the sieve and cleaning with a strong stream of water or a suitable brush. Common screen filter elements in the market are usually made of stainless steel, polypropylene, or nylon.
Filter Media: Sand & gravel
Filtrations of irrigation water with a media filter (sand/gravel). It is also called deep filtration. Media filters filter water through a thick layer of gradual particles. These particles can be sand, gravel, or other granular sorted material. The degree of filtration depends on the effective size of the bedding and the speed of the water flowing through the filter.
Sand/Media Filter Mechanism
Water enters through the filter inlet and penetrates through the filter bed. When suspended solids come into contact with medium particles, they are absorbed. Clean water then flows through the filter outlet through the sieving collector at the bottom of the filter canister.
Cleaning is done by backwashing. Water is introduced upwards from the sieving collector in the opposite direction, thereby suspending the filter bed, loosening the suspended material from the floor and flushing it through the backwash valve. Backwashing can be done automatically according to pressure difference and/or time intervals. If the water source is a river, open reservoir, or sewer, the media filter can be the heart of a drip irrigation system.