Selection criteria
Having a drum filter adapted to the needs of your installation, will guarantee complete fulfillment. It is essential to carry out an upstream study of the characteristics of your installation and the information that needs consideration to determine the selection criteria for the drum filters. However, we recommend that you consult a specialist for advice.
Resistance of the filter mesh
The durability of the filter mesh is an important requirement for a filter system such as a drum filter. Indeed, it is easily replaceable in a filter without cells and a filter panel. However, not all drum filters are of this type. Furthermore, a poor quality filter mesh would make the drum filter lose its autonomous character, as it would require a lot of maintenance. This maintenance frequency will become especially sensitive, because it is subject to oxidation throughout its use.
Therefore, we highly recommend a stainless steel mesh, with independent and easily interchangeable filter plates. This way, you will reduce the cost of maintenance that you could have with woven mesh.
Filter panel structure
Filter panels are found in drum filters. It provides structural support to the mesh of woven drum filters. However, this is not the case for all models. In fact, some models are welded and have no need for it.
These filter panels are woven, often from polyethylene, which makes them inexpensive to purchase. However, the maintenance costs will be much higher than in a stainless steel drum version.
Maintenance
a. Bearings
The bearings are the part fixed in the center of the drum, giving it good stability. It requires regular maintenance. To avoid overheating, it is important to grease this part regularly with oil.
If this operation is not carried out, not only will the filter lose its efficiency and develop abnormalities, but it may also cause a total destruction of the device. Such a scenario will have a much greater economic impact.
At 1h2o3, we decided to use a more solid bearing system that requires less maintenance.
b. Training system
The drum filter is operated by the training system.
Alternatively, belt or chain systems can be found that are less durable and require more maintenance. We therefore recommend the use of the second type of training system, if you want the greatest autonomy for your drum filter.
c. Mesh cleaning
Mesh cleaning must be automatic. However, it occurs sometimes that the mesh becomes dirty after a long period of use and needs additional cleaning. In this case, it becomes necessary to add manual maintenance.
Manual cleaning is also necessary to prevent limescale build-up. However, intensive backwash programs are available to prevent such damage.
d. Backwash ramp accessibility
Cleaning the backwash ramp is often simple, but essential. This ramp is often located above the filter, so that the rinsing process deposits the waste directly into the drainage gutter.
It is still necessary to check the pressure of the rinsing nozzles. This check is done manually. All you have to do is pass your hand under the nozzles to check that they all have the same pressure. If some of them have lower pressure, it probably means that something is obstructing the water flow. This debris can come from the filtered water. All you have to do is remove the nozzle cover and clean the inside, using a tool fine enough to penetrate.
Backwash modes
There are different backwash modes for drum filters, which can vary in intensity and frequency. This feature is one of the most important selection criteria when choosing a drum filter.
Programmed washing, as its name suggests, is programmed beforehand. It will intervene regularly to clear the filter of its “cake”. This backwash mode gives your filter a great deal of autonomy, if it is properly programmed for your needs. Moreover, it will be very water-efficient and will reduce wear caused by more aggressive and less regular rinsing.
Washing is more adaptable to the circumstances. Washing is more adaptable to the circumstances. The more it is used, the faster it will be saturated. Therefore, it happens that the programmed washing is exceeded. Consequently, the water may overflow. That’s where the pressure sensors come in. By sensing the water level rise, they will send a signal to the rinsing nozzles, which will clean the drum filter and thus lower the water level.
Some devices, like those from 1H2O3, combine these two backwash modes to ensure optimal efficiency.
Some drum filters are also equipped with an intensive washing system. This system is very practical for the prevention of limescale formation. It is also found in our drum filter range.
Energy efficiency
Energy efficiency is a priority because it can concern water savings or electricity savings. Innovation in this sector continues to grow. There are many mechanisms to push this energy efficiency to its maximum.
The advantage of this energy efficiency is that you save money directly, with reduced bills. But thanks to water savings, you will have more concentrated sludge that takes up less space.
These savings can come from several sources, as many characteristics of the filter (filter panel, gravity or pumping system, etc.) and the settings (backwash duration, backwash frequency) attributed to it allow us to reduce our consumption.
Thus, by choosing a drum filter adapted to your needs, you will be able to achieve this energy efficiency.
Emergency bypass
The emergency bypass is a prevention mechanism, integrated on drum filters by some producers. With this innovation, the contents of the drum filter are not spilled.
Indeed, when the drum filter is completely saturated, the water level will rise in the drum filter until it reaches the pressure sensors (some drums do not have them). En étant sollicité, ces capteurs vont envoyer un signal activateur aux buses de lavages, afin d’éliminer les déchets qui vont se retrouver dans la gouttière d’évacuation. However, if the pressure sensor malfunctions, the nozzles will not activate. The water level will therefore continue to rise until it overflows. If this happens, there is a risk of pollutants contained in the water being discharged directly into the soil and nearby water bodies. The emergency bypass is there to avoid this.
In summary, the emergency bypass is a tank used to retain water that would otherwise overflow, thus slowing down the water’s progression while preventing the discharge of a potentially dangerous substance.
Protective hoods (drip, mist, corrosion)
Material choice of the cover is also important in the selection criteria of a drum filter. Indeed, depending on the environment in which it will be found, it will be subject to different hazards. From simple rain, to salty winds your drum filter may be subjected to various threats.
The HDPE type plastic, although light, its main disadvantage will be its low resistance to time, if it is exposed too repeatedly to the vagaries of the weather (mist, drop, etc.), it will suffer a deformation. However, it will resist corrosion well.
Stainless steel, although heavier, will last you a long time. Especially in the face of bad weather. Il présente donc l’avantage le plus grand. It has the greatest advantage.
UV resistance for outdoor installations
If your filter is installed outdoors, it will likely be exposed to UV radiation. Some materials are not very resistant to these rays. This is reflected in a change of color, and is mainly aimed at the thinner layers. It is especially important not to leave the screens directly exposed to UV. This could damage them. There are deflectors preventing direct UV from penetrating the screen membrane.
This UV weakness can be overcome by adding an impermeable and UV-treated cover (a tarp or plastic wrap). Although simple, this solution remains impractical.
FAQ
What are the most Important Criteria for Choosing a Drum Filter?
Key criteria include the water flow rate to be filtered, the organic load of the water, the size of suspended particles, the fluid temperature, as well as the type of material (stainless steel, polypropylene, titanium). In addition, there is the resistance of the filter mesh, the type of cleaning system (backwash), maintenance requirements, and the presence or absence of safety functions such as an emergency bypass or pressure sensors. A poor choice can lead to rapid wear, poor water quality, or high costs.
What is an Emergency Bypass on a Drum Filter and is it Essential?
An emergency bypass is a diversion tank that intervenes if the automatic cleaning system fails (sensor or nozzle failure). It prevents unfiltered water from overflowing and contaminating the environment. It is a highly recommended safety feature, especially in sensitive environments or critical installations such as wastewater treatment plants or intensive fish farms.
What are the Advantages of an Intelligent Backwash System for a Drum Filter?
An intelligent backwash system adapts the mesh cleaning to the actual load of the filter. Unlike simple programmed washing, it activates based on the clogging level detected by sensors, thus optimizing water consumption and extending the drum’s lifespan. Models combining programmed + automatic + intensive washing are the most efficient, especially for preventing limescale and clogging during periods of heavy use.
Why Prefer Stainless Steel for the Structure of a Drum Filter?
Stainless steel is resistant to corrosion, UV, heat, and bad weather. Unlike plastic materials, it does not deform and offers excellent durability, even in outdoor environments. Although more expensive to purchase, it significantly reduces maintenance costs in the long term. It is recommended for industrial installations, fish farms, and hot or corrosive water.
What is the Importance of Protective Covers for an Outdoor Drum Filter?
The covers protect the filter against rain, mist, UV, and corrosion. A poor choice of material can lead to deformation (HDPE plastic exposed to sun) or premature corrosion (poorly protected stainless steel in a saline atmosphere). For outdoor installations, it is advisable to add a UV protection or waterproof cover to extend the equipment’s lifespan.
