Pumice is highly effective in water filtration thanks to its unique physical properties. As a lightweight, porous volcanic rock, it has a large surface area with excellent retention properties, making it an ideal filtration medium for many water treatment applications.
Pumice has been used for years to treat:
- Seawater
- Drinking water
- Wastewater
Pumice is a versatile filtration medium, widely used in seawater reverse osmosis (SWRO) pretreatment, desalination filtration and drinking water filtration. Let’s look at how it is used as a filtration medium.
Pumice as a filtration medium
Pumice is an excellent alternative to sand and many other filtration media. Its low specific gravity and high porosity make it well suited to treatment processes. Its benefits also extend to:
- odour control
- soil filtration
- purification of beverages and oils
Key advantages of pumice filtration media
1. Longer filter runs
Pumice can hold more solids and handle high particle loads, so filter runs are longer without affecting filtrate quality.
2. Lower head loss
Depth filtration prevents particles from building up in the upper part of the filter bed, reducing head loss across the filter.
3. Lower backwash rates
Because pumice is light (around 400 kg per cubic metre), lower backwash rates are needed to fully expand the filter bed. This brings significant savings in operating costs, with backwash requirements around 30% lower than with standard media.
4. Greater bed expansion
Being light, pumice expands more than traditional media at the same backwash rate, saving energy and water, reducing pumping requirements and allowing a smaller filtration plant.
5. Wide operating range
Pumice can be used across a wide temperature range (0–40 °C) and has been proven to perform in both saline and fresh water.
6. High filtrate quality
Pumice filtration media deliver high-quality filtrate, removing suspended solids down to 10 microns.
Pumice for odour control
In biological scrubbers, pumice removes unpleasant substances from industrial exhaust gases, such as mercaptans, H2S and VOCs.
Its advantages for odour control include:
- A larger effective surface area
- A smaller footprint thanks to its light weight
- Rapid biomass growth
- Better removal rates
- A long media life (10 years or more)
Uses of pumice in industrial water filtration
1. Municipal water treatment
In municipal water treatment works, pumice removes particles and reduces turbidity, improving water quality. In multimedia systems it is used alongside other filtration media.
2. Wastewater treatment
Pumice helps filter solids and contaminants from industrial wastewater, supporting environmental sustainability with a lower impact on local ecosystems.
3. Aquaculture and aquariums
In biological filtration systems, pumice supports the beneficial bacteria that break down waste and keep aquatic environments safe and healthy.
In short
Pumice is a natural, sustainable and effective material for water filtration systems. Its high porosity, durability and environmental credentials make it an excellent medium for removing impurities, and pumice for water filtration also supports biological filtration processes.
As industries and municipalities look for more sustainable and efficient filtration solutions, pumice remains a key element in improving water quality. Contact Keiken Engineering to find out more about pumice filtration media.
