Stephen Suau, Principal and Managing Partner of Progressive Water Resources in Sarasota, spoke for the SSWCD board meeting of March 5, 2020, at my invitation. He has recently directed treatment for the storm drains into Sarasota Bay at the new The Bay Conservancy park. He has also supervised the installation of a private water reclamation system stretching across fifty miles of Lakewood Ranch. His water engineering methods show how to reduce nitrogen and phosphorous, the “nutrient” fertilizer chemicals that feed harmful bacteria, which in turn feed blue-green algae and Red Tide.
The secret is organic matter, not more chemicals. Wood chips and sawdust in an airless environment (buried) become an organic carbon food source for denitrification bacteria. By filtering water through these, the soil captures the nitrogen and releases it back into the air, where it is harmless and necessary.
Along with nitrogen or nitrates in fertilizer-laden water, another harmful element is phosphorous, which must be absorbed, as it can’t go back into the air. The new technique for removing both phosphorous and sulphur (common in spring water in Florida), is using BIOCHAR. This material is made by heating organic matter without oxygen. It becomes activated carbon—charcoal—instead of ashes. As a soil amendment it also proves excellent for capturing phosphorous. The key is magnesium oxide, best created in carbonized sugar beets, which binds the phosphorous so it can’t leach out of the BIOCHAR. Florida will probably never grow sugar beets (we grow cane), but University of Florida is now testing pelletized Southern Yellow Pine in hopes of similar results.
Organic filters installed in streams on farms and ranches have brought amazing cost reductions for nitrate removal (from $200 per pound of nitrogen down to 36 cents per pound), with methods that can be applied to septic tank effluent and golf course runoff as well. BIOCHAR and simple, inexpensive organic materials like sawdust can help clean all the water that flows into both Lake Okeechobee and the bayous and bays of the Suncoast.
Files coming soon.