Wastewater Treatment
Reducing Nitrogen in Wastewater with Microorganisms
To protect clean water for people and wildlife - and to meet state water quality regulations - California dairy farmers are working harder to apply nitrogen to crops in more precise amounts and at the right time in the crop's growth cycle.
Our Role
Sustainable Conservation's projects have included: cultivating purple sulfur bacteria in dairy lagoons, promoting solids separators to remove and recycle organic matter and nutrients, and composting manure to produce a beneficial soil amendment. One of our latest efforts to reduce the risk of applying too much nitrogen (and potentially polluting local water) is to reduce the concentration of nitrogen in wastewater.
Sustainable Conservation and California Polytechnic State University (Cal-Poly) have teamed up to test a new technology for controlling excess organic nitrogen and odors from the wastewater of flush dairies, those that use water to clean out cow stalls. This wastewater treatment system utilizes naturally occurring microorganisms to convert nitrogen to an inert gas form, thereby removing it from the wastewater.
The technology is called a Reciprocating Biofilter (ReCip® ), which was originally developed in the early 1990's by the Tennessee Valley Authority and has been used at commercial poultry and swine facilities, as well as several other non-agricultural facilities, in the southern U.S. and internationally. The installation at the Cal-Poly dairy is the first time the technology has been used at a dairy. The biofilter at Cal-Poly has been operational since December 2009 and has consistently removed 85-95% of the total ammonia nitrogen in dairy lagoon water, with more than 50% removal of total nitrogen and total suspended solids.
Both effective and energy-efficient, this biological wastewater treatment system is an attractive option for dairy farmers who have more manure than they can utilize to fertilize their crops and are unable to acquire additional land or move the excess manure off-farm. It enables them to protect water resources and comply with Regional Water Quality Control Board nitrogen application limits.
To learn more about ReCip® or manure management research in general, contact Sustainable Conservation Project Manager Joe Choperena at (415) 977-0380 ext. 320.