Loss of Ammonia and Source of Odors
For decades, composting has been used largely as a method of waste disposal, converting undesirable heterogeneous organic materials into a homogenous soil amendment, compost. The nitrogen or plant nutrient content of compost has been a secondary issue to its soil amending and conditioning properties. Composting has also been criticized as a processing technology that reduces nitrogen values through the release of 50% of the feedstock’s nitrogen to the atmosphere in the form of ammonia. In the NaturTech system, however, virtually none of this ammonia is lost.
Stockpiling and land spreading with associated leaching and oxidation activities are also management strategies that lose nitrogen values. Ammonia released to the air is furthermore the chief source of odors at composting facilities and nitrates from unprocessed organics, especially manure, are a ground and surface water pollutant. Air emissions such as fugitive methane and volatile organic compounds are also identified as byproducts of non-aerated windrow composting, leading to regulations such as California law AB1133 enabling air quality management districts to require composting facilities to reduce air emissions to protect local air quality. Windrow composting systems are unlikely to receive carbon credits as the greenhouse gas deductions exceed sequestration credits whereas forced aeration technologies with temperature control and biofiltration prevent these emissions. The NaturTech system, representing BMP, is eligible for up to $10 per ton in carbon credits.
Odor and Leachate Control
The NaturTech Composting system has been designed to meet or exceed known environmental regulations and standards for air emissions and ground and surface water protection. The entire composting process, including curing, takes place inside sealed containers or under roof, preventing stormwater contamination. No stormwater retention basins or water treatment systems are typically required. Containerization during active digestion enables process air to be captured and treated in the containerized biofilters to remove 95% or more of odorous air emissions before exhaust air is released into the atmosphere. Air emissions are typically reduced greater than the 80% requirement of California rule AB1133 which regulates not only fugitive ammonia, but also fugitive methane and volatile organic compounds. A drain and tank system captures both leachate and condensate, enabling these liquids to be recirculated back into the initial phase of the composting process, eliminating the need for wastewater treatment.