CWC is Africa’s leading supplier of multimedia sand filter technology. Our filters have been used in every application from drinking water to minewater reclamation and our client list includes South Africa’s largest manufacturers. In recent years we have developed a range of pre-engineered multimedia sand filter units to serve the smal business, residential and light industrial markets.
A multimedia sand filter is similar in operation to a conventional sand filter, but instead of using a single layer of filter sand, CWC multimedia filters use 3 layers of proprietary filter media.
The Deep Bed Multimedia principle offers a higher degree of filtration, longer filtration cycles and lower backwash water consumption than obtained from conventional sand filters or dual media filters.
By operating the filters at higher than normal operating pressures, we are able to promote extremely fine particle size removal; typically 5-microns and better.
The differing media layer depths and particle sizes also allow for far higher solids holding capacity without turbidity leakage.
The solids retention abilities of multimedia sand filters allow them to be operated at high filtration velocities, which result in reduced installation space and capital costs.
CWC multimedia filters contain 3 layers of filter media, each of different density, granule size and material. Each mineral layer promotes continuous filtration across its surface depth.
Water is fed into the filter vessel's freeboard area, and forced through the filter media layers, exiting the filter outlet through specially designed nozzles, preventing carry-over of filter media. Suspended solids, turbidity and other particulate matter are trapped in the filter bed, producing clean, clear water.
Once the filter bed becomes blocked with dirt, a pressure drop across the system indicates that the filter should be backwashed. On automatic systems, backwashing is controlled by a timer or differential pressure switch. On manual systems, operator intervention is required to put the filter into backwash, much like a swimming pool sand filter.
During the backwashing cycle, water is forced through the filter in an upward direction, stirring up the filter bed and floating off the suspended particles. Because of the comparative weight of the filter media, only the dirt will be lost during backwash.
Once backwashing is complete, the direction of flow corrects and the filter bed is rinsed, removing any remaining dirt and helping the filter media resume its correct position inside the filter vessel.
|Model||Flow Rates||Inlet/Outlet Ports|
|Service Flow Rates||Backwash|
|Minimum flow (m³/hr)||Maximum flow (m³/hr)||Flow (m³/hr)|
Operating pressure: 200-600 kPa
Power supply (automatic units): 220 VAC 50Hz
Temperature range (water temp): 5-35°C
Multimedia filters are capable of 5-micron effluent water quality under normal operating conditions.
In order to accurately size a multimedia sand filter for your residential, commercial or industrial application, we will need to know the following:
Your local approved CWC distributor can help you calculate your filtered water needs, and can arrange for a professional water analysis to be taken. For more information about multimedia sand filters and how the CWC filtration process can help you in your home or business, contact CWC today.