Date of Award


Degree Name

MS in Civil and Environmental Engineering


Civil and Environmental Engineering


Trygve Lundquist


Reciprocating biofilters known as ReCip is a viable technology to manage nutrients, mainly nitrogen, problems at livestock operations such as swine farms and dairies. Past studies have demonstrated that ReCip is more adept at total nitrogen (TN) removal than traditional subsurface flow wetland systems. The traditional substrate used to attach biomass was rock aggregate; this media may be hard to obtain for some agricultural projects, so alternate substrates are tested and compared with the rock aggregate. The purpose of the study was twofold: first, different biofilm media were tested and compared in terms of treatment performance and, second, the long-term performance of a ReCip in continuous operation for 3 years was characterized.

Four, 2.67 square meter ReCip systems with different treatment media – rock aggregate, recycled concrete aggregate (RCA), vertical-flow plastic media, and walnut shells – were operated at a 2-day THRT over the course of a 16 week study. The TN removal efficiencies for rock aggregate, RCA, plastic media, and walnut shell media were 43%, 53%, 25%, and 69% respectively. Surface based mass TN removal rates for the same media were 103, 128, 172, and 276 kg/ha-d respectively.

A 134.2 square meter ReCip with rock aggregate media was running concurrently with the smaller ReCip systems. This ReCip was constructed ant operated since January 2010. TN removal efficiency and mass removal rate were 44% and 105 kg/ha-day. These values were close to results from the smaller rock media system.