As a contractor operating in the field of wastewater treatment, you are likely to come across Polonite in some different situations:
The Filter bags are aimed as a tertiary treatment step in on-site wastewater treatment plants. The following pre-packed filters are available as standard products:
|Type||Amount of Polonite® (kg)||Approx. measurments excl. connection pipes (diam x height mm)||Recommended minimum inner diam. av. cylindric tank (mm)|
|P301||500||840 x 1,200||1,000|
|P302||1,000||1040 x 1650||1,200|
|P303||370||840 x 900||1,000|
|P304||500||950 x 980||1,100|
Supplied in Big Bags containing 1,2 ton. For any specialized application, for larger in-situ filters with bigger filter volumes (e.g. at municipality plants)
Thanks to its unique combination of high phosphorus sorption capability and long life span, Polonite can be used in vast array of applications when phosphorus needs to be adsorbed from water.
A variant of Polonite® especially aimed for capturing zinc in effluent water. Used e.g. with Car Wash plants.
Supplied in Big Bags containing 1,2 ton. Often used at for example. car wash plants to filter away zinc from affluent water.
The principle is basically the same as for Polonite, but applied for zinc instead of phosphorus.
Zinc is one of the environmental pollutants which are toxic even at very low concentrations. Domestic and industrial discharges are probably the two most import sources of zinc in the water environment.
Domestic sources are often in the form of urban water runoffs. When in contact with water, the Zinc from zinc roofs and fences dissolves and get carried into the urban surface waters. The vehicles on the road also releases zinc from their tires when they brake.
As for industrial discharges, the metal finishing industry is one of the main sources of zinc discharge. Owning to the need to galvanize metal surfaces with zinc, the wastewater generated from these processes often has high level of zinc present in them. Another major contributing industry is the automobile servicing industry. Car washes often result in zinc leaks as zinc gets removed due to the washing process. In addition, the motor oil and hydraulic fluid used in automobiles are usually laden with zinc. It is common for the motor oil to spill on the group of the workshop during the process of changing them. By washing the oil down the drain, it ultimately causes the wastewater to have high level of zinc which is harmful if untreated.
Maximum flow through the filter
The wastewater needs to stay at least one hour in the media. As the porosity of the media is approx. 60%, this means a 500 kg filter can hold approx. 300 litres of water. Hence, the maximum flow through a 500 kg filter must be less than 300 litres per hour. Please note: This is the maximum permissible flow, but it is not recommended to continuously run the filter with maximum flow, as this will significantly shorten its life span.
Rough estimation of a Polonite® filter’s life span
For totally 90% phosphorus retention, you can use this simple formula for calculating the filter’s approximate life span: 1 m3 cumulative water-flow through the filter per kg filter media.
Example: A 500 kg filter can be expected to treat the water to a 90% retrieval requirement up to a total cumulative flow of 500m3. This is an indicative figure – in reality, the actual life span will depend on the water quality (main treatment step), pH of the water, the actual flow rate trough the filter (see above) etc.
Calendar time is in principle of no use when calculating the life span of a Polonite® filter as the water usage and occupancy differ a lot between different houses and the people living in them.
Selecting the correct size of the Polonite filter.
Our basic guide line is that you should install about 100 kg of Polonite media for each person living in the house. With this dimensioning, you can expect that the filter will efficiently retrieve phosphorus for at least 2 years.
As most wastewater treatment plants are designed for up to five persons, the 500 kg filter bag solution is the most common size. If two houses are sharing one treatment plant, a 1,000 kg filters is the logical choice.