Thinking Local Part II: Wrapping up Bioreactors, Introducing Urban Agriculture
A vision of clean water in the Chesapeake Bay watershed
Vegetation growing over an installed bioreactor in Maryland
Bioreactor installation at Ka’anapali Golf Course
Soil Biochar in West Maui
Ridge to Reefs’ roots are working the Chesapeake Bay watershed. As we grew in capacity, we realized that the same problems existed in coastal systems around the world; and that the same principle of local natural solutions would work there too. Over the years we’ve targeted our efforts to where we could do the greatest good. These days, under conditions imposed by Covid-19, we’re relying more on our partners to carry on our work overseas and focusing the efforts of our labor close to home, building on our foundations, back where we started.
Since spring of 2020, we’ve been working with a NFWF Small Watershed Grant award building bioreactors. If you’ve been following our social media this month, you’re well familiar with bioreactors and other natural water filtration structures by now (if you’ve missed these updates, go ahead and follow us on social media - we have more exciting content coming!).
For a quick recap, bioreactors are one of the many local natural solutions we build to clean up watersheds. First, we identify a source of problematic water; say a field is fertilized, and when it rains some of that fertilizer washes into the river or leaches into groundwater, threatening human health; then continues into the bay, causing all sorts of ecosystem imbalances (harmful algal blooms, unbalancing up the oxygen concentration, threatening fish). It would be great if there was a way to filter out the fertilizer, right? Fortunately, nature has a way of doing that. In short, helpful bacteria naturally found in the soil can consume nitrates from fertilizer and convert it to inert nitrogen gas (that makes up ¾ of the fresh air that we need to breathe)! It’s a remarkably efficient and effective process; the planet has had time to work this stuff out! Our job is to identify where the problem sources of water are coming from, direct this water to a natural filtration system, and hold the runoff water in place long enough for the bacteria to have their feast. Enter the bioreactor!
A bioreactor is essentially a lined trench filled with woodchips and various soil media. First, we put on our boots and dig out a trench. This trench only needs to be about four feet deep and are typically 30’ wide x 100’ long to treat 100 acres of cropland! We add a liner so the water doesn’t leach out into the soil while it’s being filtered, and fill the liner with biochar, which is a special kind of charcoal made under specific oxygen-depleted conditions. This charcoal filter is excellent at removing phosphorous content, for those of you out there keeping score - and it also helps the beneficial nitrifying and denitrifying bacteria grow; a win-win for water quality!
Bioreactors (which we now know is a lined drainage ditch filled with wood chips, biochar, and safe helpful bacteria) are an established practice; Ridge to Reefs has done a lot of pioneering work making them more efficient and piloting applications for creatively solving water quality problems. We’ve built them and other natural filtration systems around the world in places that need a locally-made natural, safe, self-sustaining water treatment system. Check out some of our work with bioreactors on our projects page.
Next month we’re featuring urban agriculture! If you missed the social media updates this month give us a follow at the links below, and don’t forget to subscribe to our newsletter for more news about taking care of the people and the planet delivered straight to your inbox. Stay well and drink plenty of water! Nature’s got you covered.