Choosing the Right Fluoride Removal Method: A Comprehensive Guide to Bone Char vs Activated Alumina Filtration
For homeowners concerned about fluoride in their drinking water, understanding the differences between bone char and activated alumina filtration methods is crucial for making an informed decision. Both bone char and activated alumina are among the three EPA and WQA recommended methods for removing fluoride from drinking water, but each has distinct advantages and limitations that affect their performance and suitability for different situations.
Understanding Bone Char Filtration
Bone char has been used for centuries to remove naturally-occurring fluoride from water and works similar to the way bones in the human body attract fluoride. Bone char is actually the remains of animal bones that have been crushed, exposed to high furnace temperatures and carbonised, containing a carbon structure while supporting a porous hydroxyapatite matrix.
The reduction of fluoride is a combination of adsorption of fluoride by the hydroxyapatite, adsorption by the activated carbon and partial ion exchange with available OH ions. Recent scientific studies have shown promising results, with bone char outperforming activated alumina for fluoride removal by a factor greater than 3 in controlled laboratory conditions.
However, bone char’s effectiveness varies significantly. It is said to achieve up to a 90% removal rate, though real-world performance can be lower. On average, fluoride removal was 67% thus leaving 33% or 1/3 of the fluoride in the water in some testing scenarios.
Activated Alumina: The Industry Standard
Activated alumina is aluminum oxide, the same chemical substance as sapphire and rubies, but without the impurities that give the gems their color. (This is not aluminum, which is a more highly-processed metal made from activated alumina.) Activated alumina is recognized as the best available technology for fluoride removal from drinking water by the United States Environmental Protection Agency.
It is said to be 98 to 100% effective, as long as you get the flow rate just right. There is an additional bonus of also removing arsenic and lead. Activated alumina has a very high surface-area-to-weight ratio, with a lot of tunnel-like pores that run all through it.
Cost Considerations
One significant factor in choosing between these methods is cost. Properly prepared activated alumina can cost 20x that of bone char. Additionally, bone char is more expensive per cubic foot and it takes six times the volume of media to complete the same task. Per cubic foot bone char only filters about 1/2 a gallon per minute compared to Activated Alumina that is 3 gallons per minute.
Water Chemistry Challenges
The effectiveness of both methods is heavily influenced by water chemistry conditions. The capacity for fluoride drops precipitously by 50% or more when feed water pH is 8.2 and bicarbonate alkalinity (essentially hardness) exceeds 50 PPM (3 grains). This eliminates effectiveness on 85% of municipal water supplies for activated alumina systems.
Similarly, bone char faces challenges with water chemistry. It requires a low pH (below 6.5 is recommended), low flow rates and frequent replacement of cartridges. While new Bone Char cartridges are claimed to reduce fluoride by up to 90%, in controlled laboratory tests after only 50 litres (10 gallons) fluoride removal dropped from 80% to 50%.
Environmental and Health Considerations
Bonechar is more environmentally friendly and potentially a lower-cost alternative adsorbent when compared to activated alumina because it can be produced near its point-of-use from bones harvested from food waste. The economic and environmental costs of activated alumina are also substantial, with approximately 200 million USD spent on 33,000 tonnes of activated alumina for water treatment globally in 2015, having a carbon footprint of >80,000 tonnes of carbon dioxide gas equivalents.
Regarding aluminum leaching concerns, leaching of Aluminium is not a concern for NSF approved Activated Alumina. All NSF certificated media must meet criteria to be considered safe. Concentrations of impurities can not be exceeded to pass NSF stringent requirements and to earn certification.
Professional Installation and Maintenance
Both filtration methods require proper installation and regular maintenance to ensure optimal performance. A half volume of activate alumina is insufficient for 90%+ removal – it requires a long contact time. Only cartridges 100% filled with fluoride media provide maximum contact time at recommended flow rate.
For residents in Central Florida seeking professional water treatment solutions, working with experienced providers is essential. Quality Safe Water of Florida understands the unique water challenges in the region. Quality Safe Water of Florida is dedicated to ensuring every Florida family has access to clean, safe, and purified water. They are committed to providing the highest quality, efficient, and affordable water treatment solutions, prioritizing the health and well-being of their customers.
When considering a water filtration system Lake County, FL residents can benefit from professional consultation to determine which fluoride removal method best suits their specific water conditions and household needs.
Making the Right Choice
The choice between bone char and activated alumina depends on several factors including water chemistry, budget, flow rate requirements, and environmental preferences. To truly make the best water filtration choice, it’s wise to invest in a thorough water test and determine what is in your water to start with.
While activated alumina offers higher efficiency and faster flow rates, bone char provides an environmentally sustainable option that can be highly effective under the right conditions. Both methods require careful consideration of your specific water conditions and professional installation to achieve optimal results.
Ultimately, the most important step is taking action to address fluoride concerns in your drinking water. Whether you choose bone char or activated alumina, both represent significant improvements over untreated water for families concerned about fluoride exposure.