Multimedia Filtration

Hydroflux HyPURE range of multimedia filtration systems utilise advanced, in-house designed and manufactured pressure filtration systems to treat fine and colloidal solids, as well as some dissolved species from water.

Media filtration use several different physical process to remove fine and colloidal particles form suspension. The process consists of a pressure vessel, filled with different media types which are specifically selected for the particular process.

Hydroflux offer a wide range of media options for variety of applications, which are discussed in more detail here.
The filtration vessels can be manufactured from fiber reinforced plastic (FRP), painted mild steel or stainless steel.

The first step of the filtration process infolves raw or waste water entering the pressure vessels through a set of top mounted diffusers. The diffusers disperse water inside the vessel, ensuring a uniform downflow velocity through the vessel.

Once the water is dispersed within the vessel, it flows down through the media bed. Hydroflux custom designed vessels allows flexibility in bed depth without reducing free-board above the vessel, which is key to effective backwashing. The typical bed depth is 800mm – 1200mm, but deeper beds can also be provided for special activated carbon adsorbtion and desalination calcite remineralisation processes.

As water flows through the bed pollutants are removed through several physio-chemical processes, including size exclusion (filtration), adsorption and cake formation within the bed. Biological degradation of pollutants can also occur in some filters, although in many cases this is not desired due to the sloughing of bacterial colonies into the treated water and reduced filter run-times. Hydroflux understand the challenges of biofouling within filtration beds and offer simple solutions for maintaining the integrity of the filtration media.

The filtered water is collected by a bottom nozzle plate, which prevents media from escaping in the treated water. The filtered product is typically directed to a filtration tank which provides a reservoir for the backwash process. In some instances it is possible to backwash without the use of filtered water.

Hydroflux HyPURE systems used advanced automation for the control of the backwash cycle to minimise unnecessary backwashing during periods where the solids loading in the feed water is low. This is particularly advantageous in biological wastewater recycling, where changes in upstream conditions can lead to volatility in the solids and organic content entering the filters.

For most HyPURE applications, Hydroflux will also provide an air scour as part of the backwash cycle. Dedicated air scour blowers are provided to enhance bed cleaning and prevent rat-hole formation.

Hydroflux HyPURE media filtration systems are some of the most robust and advanced available on the market. Please click on the links below for additional information.

Hydroflux HyPURE – Industrial Multimedia Filtration systems
What is the capacity range of the HyPURE Multimedia systems?
The HyPURE range is individually designed to suit customer requirements, the treatment capacity can range from <1m3/D up to and above 5000m3/D. Generally flows above this are more suited to gravity filtration. We have standard sizes that we manufacture, but due to the variability of the site conditions, feed water quality and available space in the plant each solution must be tailored to suit.

What are the typical sizes of the pressure filtration vessels.
Pressure filtration vessels are generally cylinders, mounted horizontally or vertically. Vertical vessels range from 300mm to 3m in diameter. Horizontal vessels are generally 2.2m in diameter to minimise shipping costs but can provide anywhere up to 10m2 in available filtration area by increasing the vessel length.
What type of maintenance is required on a HyPURE Multimedia system?
HyPURE MMFs are designed for extended maintenance free operating periods. Typically no maintenance is required for several years. The most frequent activity required is media replacement, which can be every 5 to 10 years for sand filtration down to 3 to 6 monthly for activated carbon filtration.

The HyPURE system has several advantages over conventional media filtration systems, as the use of bottom nozzle plates means that less downtime is needed for maintenance compared with bottom lateral diffuser designs. In addition, the HyPURE system uses independent control valves compared with a single multiport valve to control the filtration cycle.

Multiport valves are prone to breakdowns/failures and generally have a high replacement cost and long lead time. Individual parts for control valves and actuator heads are readily available and low cost to purchase. Operation of the HyPURE Multimedia plant can also be controlled remotely through the HyCONNECT® system.
Do Multimedia Filtration system require a lot of power?
Generally speaking, MMF systems require a lot less power than other types of filtration technology, such as ultrafiltration and reverse osmosis. The power is also influenced greatly by the feed TSS. The rate which the media bed differential pressure increases subsequently increases power required by the feed pump. The media bed also requires more frequent backwashing which impacts on the total energy consumption of the plant. Generally MMF systems operate at between 0.8 and 1.5 BarG.
How small are the particles which can be removed by the HyPURE Multimedia filtration
The purpose of the filtration bed is to capture fine colloidal material down to <2micron, which is 10x smaller than a human hair.

Can the HyPURE Multimedia filtration system handle iron, manganese and other heavy metals in the feed water?
MMF systems can handle dissolved heavy metals within the feed water, as long as the total concentration does not exceed the design feedwater levels of the filter. Hydroflux® offer a range of specialised media to maximise the metal precipitation and removal within the filter bed. This is done by catalysing the formation of metal oxides and metal hydroxides either infront of the MMF or within the filtration bed itself.
What is the purpose of an air scour in the bakcwash cycle of an MMF?
Air scouring of the filter bed is recommended to extend the bed life. During operation and backwashing, the media bed can form “rat-holes” or channels which allow pollutants to pass through unhindered. Air scouring the bed provides a mechanisms for more aggressive cleaning. Air soucring allows the media bed to be completely and evenly mixed within the vessel. The subsequent backwashing and settling of the media allows the bed to reform evenly, even when multiple grades of media are present in the one vessel.

How is the media replaced?
Media replacement can be done by several different means. Spent media is usually sucked out of the vessel via a vacuum truck and carted from site to be recycled or disposed. It is also possible to unload some low density media (such as activated carbon) via a hydraulic transfer to a specially designed screen to capture the media.
The most common method of loading the replacement media is directly filling from an elevated work platform or conveyor into the top of the vessel. Media can also be loaded in via large bulk bags, or pumped in from trucks or small tanks with specially designed loading systems. Hydroflux® hold media loading systems in our warehouse to assist customers with media replacement.