Abstract: A modular, on-site, wastewater treatment system removes total nitrogen, phosphorus, BOD, and TSS. A flow equalization module provides a constant flow rate to the system eliminating the adverse effects from variations in flow rate throughout the day. Treatment modules are similarly sized to provide a compact, modular system. The nitrification module is a fixed-film, flooded packed bioreactor to facilitate bioconversion of ammonia to nitrate. Aeration of the module provides the oxygen needed for the bioconversion as well prevents clogging of the film. Solids from the nitrification process are removed in a first cone-shaped settling tank. De-nitrification where nitrate is converted to nitrogen gas takes place in an anaerobic fixed-film bioreactor. Carbon-based bio-film carriers provide a carbon source for de-nitrification. A final cone-shaped settling tank separates solids from the treated wastewater. Additional modules to address removal of phosphorous or other contaminants can be added to the modular system.

Abstract: A carbon-based biofilm carrier is formed of saturated fatty acids and saturated fatty alcohols. The carriers are shaped with a hollow center and have a length that ranges from bout 0.3 to about 1.5 times its outer diameter. The shape provides both maximum surface area and maximum protection during aerobic and anaerobic biological treatment of wastewater.