Pumice is a lightweight aggregate which has been used in numerous applications since the Roman Times. It is a volcanic rock consisting of highly vesicular volcanic glass. It is typically light in colour but can also occur darker, and is created when super-heated, highly pressurised rock is violently ejected from a volcano and then cools rapidly within the atmosphere. It is ground and milled to required specifications for particular application areas. These include for use in lightweight concrete, abrasives, polishes, PCB boards, dental applications, glass treatment, cosmetic exfoliates, and in the production of stone-washed jeans. In recent years it has also found an ever increasing market in bio filters and other water filtration systems, and within the horticultural industry.
Through years of experience and knowledge we are able to supply pumice powder, grains, pellets, blocks and aggregate.
Pumice in Water and Wastewater Treatment
Pumice grains are used within dual and multimedia filters in waste water, potable water and seawater reverse osmosis (SWRO) treatment plants. Most recently, a major application of pumice grains can be found in the pre-treatment processes of reverse osmosis (RO) desalination systems. The pumice ensures the removal of particulates in gravity and pressure filtration systems thus preventing the fouling of membranes.
Recommended grades include the pumice NMP4 and NMP4N grains. In multi-media filters, we are also able to supply supplementary filtration grains including sand and anthracite.
Testing: Further to our detailed specifications, our pumice grades have been tested in action, using a state-of-the-art testing rig. Results include accurate data on back-washing rates vs bed expansion, head loss vs water rate, against variations in temperature and salinity. We also offer comprehensive results on the particle size, porosity, hardness, attrition, density and chemical composition.
For further information and results please contact us – an example can be found on the right.
Pumice lumps are also used in bioscrubbers and biofilters, acting as a support medium for bacteria. Polluted air passes through the pumice biofilm, where microbes enable the transfer of contaminants into the liquid medium through oxidation. Such units are installed throughout waste water, sewage and industrial effluent systems enabling the treatment of hydrogen sulphide and other volatile organic compounds. Its low density, high surface area, neutral pH and high strength make pumice an ideal material within these systems. Pumice can also act as a longer term solution to fast degrading organic alternatives such as peat, heather and wood chippings.
Pumice for constructed wetlands
Pumice lumps have been used worldwide as a substrate within constructed wetlands, which are becoming an increasingly popular addition to wastewater treatment processes. They represent the function of natural wetlands being used to remove sediments and pollutants from water. Pumice can offer distinct advantages over gravel and sand alternatives through its lightweight characteristics. This is particularly important in situations where the local topology presents low load bearing capacity.
In methanisation processes, pumice can be used as an effective biomass support. Here, organic solids are broken down by anaerobic bacteria in an oxygen-deprived pumice medium to produce carbon dioxide and methane gas. These processes may be used in a range of industrial applications, including the treatment of effluent derived from sugar beet and paper manufacturing. This offers advantageous conditions for biomass growth whilst also presenting low friability and acid loss. Through increased bacterial concentrations plant efficiency is also improved.
If you have a requirement for good quality pumice at competitive prices please do not hesitate to contact us.
The pumice product range includes
Pumice Aggregate, Pumice Blocks, Pumice Pellets and Pumice Powder
PUMICE PIZZA OVEN KIT (£70.00 plus delivery charges) – Two 25kg bags of 10-15mm grade, ideal for pizza oven manufacture.
PUMICE SLUG REPELLANT KIT (£70.00 plus delivery) – Two 25kg bags of our pumice garden grade.
The abrasive nature of pumice makes it an ideal barrier for protecting your garden from slugs and snails. The porous structure of pumice can be further mixed into the top soil to improve aeration and drainage.
For further details please also visit the Pumex website, of which Richard Baker Harrison Ltd have now taken over.