Many architects and engineers are now specifying a sewage treatment plant followed by a tertiary treatment module in place of a large percolation area.
Tertiary treatment modules include the following;
Sand filters are very effective for tertiary treatment. They are layers of certified silica sands and gravels installed to EPA designs. Limitations of sand filters are that they can be large, expensive to install and require a certain degree of skill by the installer.
There are some new tertiary treatment products on the market now that use waste organic material like peanut shells and coconut shell fragments to treat wastewater. These systems come in a tank preinstalled. Drawbacks of the systems are that they use waste organic filter material that needs regular replacement. Suppliers may tell you otherwise, but our advice is read the small print and get it in writing! The only advantage versus a sand filter is that they are tank based systems so they are simple to install.
Biocell offers filterpods for tertiary treatment. Certified to EN12566-3 and EN12566-7. The systems come plug and play as a small tank that can be installed in place of a percolation area. The filter media is synthetic – so none of the problems that you get with organic filter media as discussed above. Far better value and easier to install than sand filters.