Saint-Gobain Byggevarer AS
Weber is one of the leading suppliers of building materials in Norway. Among the products produced are the expended clay filter media Filtralite. Clay is burned to make a porous ceramic product with very good properties for different types of treatment of wastewater and potable water. The main areas of use of Filtralite are: Municipal wastewater, municipal drinking water, on-site wastewater treatment and pretreatment for desalination.
Weber has during the last decade delivered Filtralite filter media to numerous wastewater treatment plants around the world. Treatment of wastewater is very important for avoiding pollution of the natural water resources.
One of the main substances to remove from the wastewater is Nitrogen. Many wastewater treatment plants use Filtralite for nitrification and denitrification purposes. The “engine” in these types of plants is bacteria that degrade the Nitrogen and Carbon substances in the water. These bacteria grow as a biofilm on the very porous and large surface area of the Filtralite filter media. Plants using this technology, called fixed film biofilters, have a significantly smaller footprint than more traditional biological treatment processes.
Municipal drinking water
Drinking water is our most important source of nutrients. To achieve good quality drinking water, different types of treatment are used. For these treatment processes Filtralite is an excellent filter media.
If surface water is used as raw water source for the waterworks, coagulation and filtration followed by disinfection is a good method for producing good and safe drinking water. Filtralite has been installed in several such waterworks during the last years. The experiences from these plants, and pilot tests carried out, are that Filtralite, due to its porosity, allows longer filter runs than traditional filter media. This results in reduced water and energy consumption for cleaning the filters.
Ground water can often contain metals and minerals that should be removed before the water is consumed. Many of these contaminants are biodegradable, which means that biological treatment of the water is suitable. Filtralite has shown to have very good properties as filter media in these types of biofilters and have been delivered to huge waterworks, for instance in Hong Kong, but also in very small waterworks in rural areas. One such small plant is located in Yellow Quill in Canada. In this plant the biofilters removes Iron, Ammonia, Arsenic and particles to very low levels.
On-site wastewater treatment
In rural areas it is very expensive to collect wastewater for central treatment works. Therefore it is a good idea to treat the wastewater locally, either for each single house or for clusters of houses. This can be done in a filter bed solution.
In such a filter bed plant the wastewater first goes to a septic tank. From the septic tank the water is pumped and sprayed over a prefilter with Filtralite. This prefilter is a biological trickling filter degrading biodegradable matters. From the prefilter the water flows into the filter bed, which is filled with the special filter media Filtralite P that takes up Phosphorus. After passing through the filter bed, the water can be disposed into most kinds of recipients. The Filtralite P media will, after around 15 years, be saturated with Phosphorus. The media can then be used for soil conditioning, both for making the soil more porous and also adding the very important nutrient Phosphorus to the soil.
Pretreatment for desalination
Weber has delivered Filtralite for several desalination plants for filtration before reverse osmosis (RO). Filtralite has excellent properties for use in pretreatment filters in desalination plants, both in filters for filtration of coagulated water and in biological processes. Use of Filtralite will provide low SDI values, reduced danger of biofouling of the RO membranes and long filter runs between backwashes.