Date of Award


Degree Name

MS in Civil and Environmental Engineering


Civil and Environmental Engineering


Tryg Lundquist


Removal of organic matter and nitrogen from concentrated wastewaters is often a complex and costly process that is rarely implemented in animal agriculture, such as the dairy industry, despite regulatory pressures and the high cost of land for manure application in some regions. This paper describes results from the first implementation for treatment of dairy farm wastewater of the relatively simple ReCip® technology. ReCip® typically consists of two basins filled with rock aggregate through which wastewater is flowed in series. One basin is full of wastewater and the other is only partially full. Wastewater is alternately pumped between the basins (reciprocated), which exposes biofilm on the aggregate to air and then submerges it, repeatedly creating aerobic and then anoxic conditions. These conditions promote nitrification and denitrification, in addition to removal of organic matter through biodegradation. The present study reports on 149 days of operation of a pilot-scale ReCip® system treating anaerobic lagoon wastewater at a California flush dairy. The resulting removals of wastewater constituents were 94% of total ammonia nitrogen (TAN), 49% of total nitrogen, 56% of five-day carbonaceous biological oxygen demand, and 61% of total suspended solids. A simple mathematical model, which considers influent TAN concentration and temperature, was capable of predicting TAN removal. Preliminary results of air quality emission monitoring indicate releases of nitrous oxide, methane, and carbon dioxide from the basins during system operation. Additional studies are currently underway to further quantify air emissions, test various ReCip® operating conditions, and develop scale-up cost estimates.