Why choose sand and gravel that meet the AWWA B100-16 standard for water filters?
In sand and gravel filters, granular media perform essential functions: sand acts as the filtering medium, retaining suspended particles, while gravel serves as a support layer for the sand or other granular media.
Because these materials have been used for so long, we often overlook the importance of ensuring that they possess the proper properties.
These properties directly affect filtration efficiency, system stability, and the quality of treated water. At Carbotecnia, we offer sand and gravel that comply with the ANSI/AWWA B100-16 standard, because we understand that investing in quality materials is key to ensuring reliable operation and consistent performance.
1. Ideal chemical properties of sand and gravel: preventing the release of undesirable compounds
Many sand and gravel sources present chemical composition issues that make them unsuitable for filtration use. Common examples include:
- High levels of soluble salts, which can impart taste to treated water or interfere with other processes.
- Limestone gravel containing calcium carbonate can slowly dissolve, affecting the pH of the water and introducing undesired hardness.
The AWWA B100-16 standard establishes that solubility in a hydrochloric acid solution at approximately 18% by weight must not exceed 5%. This criterion ensures that both gravel and sand are chemically stable and will not release contaminants or alter water quality.
2. Physical properties of sand and gravel: key to efficient filtration
Regarding their physical properties, both silica sand and support gravel must consist of hard, durable, and dense grains that can withstand degradation during handling and operation.
Poor classification can cause void spaces, flow channeling, clogging, or even loss of media during operation.
- In the case of silica sand, the AWWA B100-16 standard specifies a controlled particle size distribution to ensure uniform and effective filtration.
- The support gravel must be free of fines (clay, dust) that can saturate the system and require large volumes of water for initial cleaning.
- In many cases, local gravel does not consistently meet these conditions, so we use premium gravel that is properly classified according to the standard.
Additionally, the following criteria must be met:
- Size ratio between adjacent layers (no greater than 4:1).
- The support gravel must be free of fines (clay, dust) that can saturate the system and require large volumes of water for initial cleaning.
- Proper distribution to prevent the loss of filter media through the underdrain.
3. Smooth installation and operation
Using high-quality sand and gravel filters prevents common operational issues such as:
- Flow channeling, which reduces filtration effectiveness.
- Loss of filter media due to improper retention.
- Increased maintenance costs from clogging or frequent replacement.
It also allows for more efficient backwashing, saving water, energy, and time during system operation.
At Carbotecnia, we carefully select and supply sand and gravel filters that meet the ANSI/AWWA B100-16 standard, backed by verified quality control and technical data sheets. This ensures our clients receive reliable, ready-to-install products with proven field performance.
We know these materials may cost more than generic options, but they represent significant long-term savings by preventing operational failures, system downtime, and reprocessing caused by poor water quality.
