What are Media Filters?
When it comes to water treatment, the term filter media refers to the elimination of suspended solids from water. In most cases, this is the last step in water pre-treatment before ion exchange or reverse osmosis treatment to remove insoluble impurities.
Prior to filtration, coagulation, flocculation, and clarification are performed. Depending on the flow of the water, media filters used in water and wastewater treatment are either pressure or gravity filters. The water is pumped through the pressure filter, while the water flows through the gravity filter on its own. As filter media, they use granular media such as sand, anthracite, or activated carbon, either alone or in combination. Special media filters are also used to remove iron and/or manganese, which may be present in some well water. Filter media uses a variety of media to remove contaminants, depending on the application and requirements.
· Direction of flow
· Types of filter media or bed
· Driving Force
· Method of flow rate control
· Filter and loading rate
Stages of filter media
In the first stage, wastewater is routed through the facility using three different combinations of filter media. The first mixture consists of gravel, silica rock, and zeolite. The second filter assembly contains gravel, silica rock, activated carbon, and zeolite, while the third contains gravel, silica rock, activated carbon, and zeolite. Wastewater is routed through the facility, samples are collected using the first, second, and third combinations, and control is routed without the use of filter media.
The second stage employs the best combination of filter media and conditions it by soaking the best combination of filters in the wastewater for 7 days; the wastewater then passes through the facility.
Uses of Media Filters
-Storm Water: Water quality in streams, rivers, and lakes is protected by using media filters. They can be effective at removing pollutants such as suspended solids and phosphorus from stormwater. The most common filter material is sand. Wood chips or leaf mould may be used in other filters, which are sometimes referred to as "organic filters."
-Drinking Water: For purification, municipal drinking water systems frequently use a rapid sand filter and/or a slow sand filter. The most commonly used medium in such filters is silica sand. Alternative filter media include anthracite coal, garnet sand, ilmenite, granular activated carbon, manganese green sand, and crushed recycled glass.
-Sewage and Waste Water: Media filters are often used to clean septic tank and primary settlement tank effluent. Sand, peat, and natural stone fibre are common materials.
-Oil and gas industry: Media filters are used in the oil and gas industry for a variety of purposes in both upstream and downstream operations. Nut shell filters are commonly used as a tertiary oil expulsion step in produced water treatment. Sand filters are frequently used to remove fine solids from oil refinery wastewater after biological treatment and clarification. Filters with multiple media are used to eliminate suspended solids from both produced water and refinery wastewater. Gravel, sand, garnet, and anthracite are common materials used in multi-media filters.
Suspended Media Filter
Sewage treatment plants/wastewater processes can be classified as one of the following systems:
- Activated Sludge herb (ASP)
- Rotating Disk System
- Submerged Aerated Filtration (SAF)
- Suspended Media Filters (SMF)
- Sequencing Batch Reactor (SBR)
- Non-electric Filter
- Trickling Filter
The SMF series media filters are intended to eliminate suspended solids from water and fluid systems. Solids are eliminated to a 5micron level using specialised permanent media. The pressure drop across the media increases as solids are removed. Based on pressure drop or time, the unit will automatically backwash to self-clean the media.
For information on STP’s or ETP’s, contact Netsol Water!