All plants require certain nutrients to grow. One of these nutrients is nitrogen. Nitrogen is most readily available to plants in the form of nitrate. Nitrate is usually applied to plants in levels greater than can be taken up by the plants in order to make sure that enough is absorbed. The excess nitrate either runs off the property in the agricultural runoff or is absorbed into the ground past the root zone of the plants and into the groundwater. Unfortunately, nitrate is a contaminant in drinking water at levels commonly found in agricultural runoff.

Converting that nitrate to a less harmful form of nitrogen before it enters the drinking water helps protect the drinking water supply. Once nitrate is in the drinking water, it is expensive to remove. Finding an inexpensive way to remove nitrate before it enters the drinking water helps protect the drinking water supply.

Nitrate can be converted to nitrogen gas by a certain kind of bacteria. These bacteria are called denitrifiers and occur naturally in the environment. They grow when conditions suit them. They prefer warmer temperatures, a source of carbon, and no oxygen. Those conditions are normally found in marshes and bogs or other wetland like locations.

Woodchip biofilters provide both a carbon source and a place for bacteria to grow to convert nitrate to nitrogen gas. We can create those conditions to encourage the growth of these bacteria and encourage the conversion of nitrate to nitrogen gas. The atmosphere is 80% nitrogen gas so this conversion reverts nitrate into a harmless atmospheric gas.