Gravity Media Filters
With so many efforts nowadays in trying to have a sustainable environment, there are more stringent discharge limits than ever before which communities have to adhere to. Enhanced nutrient removal provides the greatest quality effluent by lowering phosphorus and nitrogen levels. To ensure that your area produces the highest quality effluent possible with enhanced nutrient removal solutions, it is imperative to know the steps to take with your wastewater technology. A good example is Gravity Media Filters.
Filtration is a process of separating a solid from a liquid. The liquid is separated from the solid by passing the mixture over a filtering media. The filtering media is chemically inert to the mixture, and having very small pathways for the liquid to pass through, but the pathways are smaller than the solid particle size. The filtering media can be made using fritted-glass, paper, or any porous material. Gravity media filter systems use granular particles in a basin. A fluid streams pass through the basin and the particles are chemically and/or physically captured by media.
Gravity filters are normally used in areas where liquid-solids separation is needed in various applications for finished water treatment. The gravity filters can incorporate different types of media such as anthracite, sand and greensand to meet each application’s water treatment needs. Additionally, the gravity filters allow for very easy inspection during the process and usually have a smaller profile.
Gravity Media Filters are available in a variety of designs and configurations that can be customized to meet a variety of constraints such as footprint, water quality, flow requirements and backwash requirements. The filter designs can be either rectangular or round and can be either multi-cell or single. Additionally, systems can be developed for self-contained backwash storage and this eliminates the need for backwash pumps.
Gravity filters are normally developed using painted carbon steel; however, the systems can also be made from corrosion-resistant materials such as aluminum or stainless steel. Gravity filters helps in design flexibility and this helps in fitting into tight footprint requirements when required.
Gravity filter internals can be customized based on the customer’s preferences and applications. Various options are available for overdrain and underdrain design. The options allow for different types of air scour and backwash, like baffled overdrains for combined water and air backwash.
The mixture can be pushed through the filter by either reduced pressure on one side of the filter or gravity. You can separate a solid from a liquid by either technique, but there are advantages to each technique.
Gravity Filtration is recommended when:
- the liquid is saturated with one or more reagents
- the mixture is hot /above room temperature
- the solvent is very volatile such as alcohols, chloroform, ethers.
The impurities commonly removed by Gravity Media Filters include; Iron & Manganese, Suspended Solids, Taste & Odor, Color and Organics (TOC’s & SOC’s)
Gravity media filters are custom designed and built for a wide variety of municipal and industrial applications. As its name suggests, gravity is used as the motive for the fluid stream to pass through a granular media through which chemical and/or physical removal of impurities is achieved. Gravity media filters are ideal for treating larger volumes of mixtures than pressure filters can economically achieve.
