Reduction of Malodorous Compounds from Liquid Swine Manure by a Multi-Stage Treatment System

Abstract

A full-scale swine wastewater treatment system was designed and implemented to replace anaerobic lagoon treatment systems with a three-stage process of solids separation, biological nitrogen (N) removal, and phosphorus recovery. Our study had the objectives of evaluating both the system's efficiency for odor control and water quality parameters that better indicate odor reduction. This report presents data on the concentration in liquid of six selected malodorous compounds (phenol, p-cresol, p-ethylphenol, p-propylphenol, indole, and skatole) and 15 water quality parameters measured at the three successive stages of the treatment process. Solid phase extraction of odor compounds showed that the concentrations of malodorous compounds were reduced by almost 98% in the treated effluent as compared to untreated raw flushed manure. The majority of this odor reduction occurred during biological N treatment. No single water quality parameter served as the sole indicator for the levels of all six odor compounds that we measured in wastewater. Except for phenol, the levels of ammonia N and electrical conductivity (EC) measurements were highly correlated with reduction of individual malodorous compounds in wastewater. Seven out of 15 parameters measured (soluble COD, soluble BOD, TKN, ammonia-N, nitrate-N, alkalinity, and EC) were found to be highly related to reduction of total measured malodorous compounds. These results suggest that selected water quality parameters in swine wastewater could assist to evaluate odor control measures when no sensory analysis or appropriate analytical equipment is available. They also indicate that treatment systems incorporating biological N removal can greatly reduce malodorous compounds in liquid swine manure.