Mitigating Odors from Agricultural Facilities: A Review of Literature Concerning Biofilters

Abstract

This article reviews literature on biofilter research both in laboratories and at confined livestock facilities. The purpose is to give an up-to-date review of biofilters used to mitigate of odors and volatile organic compounds (VOCs) from agricultural facilities using biofilters. More specifically the article addresses: 1) Factors concerned in design and operation of biofilters such as media property, empty bed residence time, media moisture measurement and control, microbial ecology, construction, and operation cost; and 2) Biofilter performance such as odor/VOC reduction efficiency (RE), and air pressure drop. Lab-scale, pilot-scale, and full-scale biofilter studies were reviewed. Biofilter design and odor/VOC REs were summarized in tables for easy reference and for a perspective on the current state of the art. The relationship between the biofilter configuration/operation factors and biofiter performance was discussed. This literature study indicates: 1) Biofilters can be used as an effective technology for reducing odor/VOC emissions from animal facilities (RE up to 99% for odor and up to 86% for 16 odorous VOCs reported); 2) The three most important factors effecting biofilter performance are packing media, media moisture content, and empty bed residence time; 3) Removal efficiency, air pressure drop, and construction/operation cost are three parameters of concern when a biofilter is installed and operated; and 4) Further studies such as developing precise media moisture measurement and control technologies, bacterial structure, and long time full-scale biofilter tests are needed to better understand the biofiltration process and improve biofilter applications for agriculture.

Strategies to control odours in livestock facilities: a critical review

“…When the air passes through a wet organic packing material, odours are first retained in the material surface and then decomposed by microorganisms (Revah & Morgan-Sagastume, 2005). The reported efficiency lies within the range from 80% to 99%, depending on the packing material, its moisture content and the empty bed retention time (Chen & Hoff, 2009). To obtain maximum odour and ammonia reductions, these systems should be installed after a chemical scrubber, thus removing NH 3 and odours in two separate stages (KTBL, 2006).…”

Influence of key physicochemical and hydrodynamic specifications of three packing materials on both performance and bacterial community structure of gas‐biofilters

“…For both selection and management of the biofilter media, high specific surface area for development of a microbial biofilm and gas–biofilm mass transfer, nutritional requirements for microbial growth, i.e. moisture, temperature, and nutrients, high porosity for minimizing pressure drop across the biofilter and good moisture holding capacity must then be carefully considered . Moreover, an optimal packing material should have high durability, to allow minimizing the frequency of replacement and a low purchase price, to reduce investment costs…”

Butyric Acid- and Dimethyl Disulfide-Assimilating Microorganisms in a Biofilter Treating Air Emissions from a Livestock Facility

“…Biofilters rely on the versatile metabolic pathways of microorganisms, which are exposed to air contamination and transform these compounds into biomass, carbon dioxide, and water, as well as waste products. These waste products are washed away by "trickle" action, thereby maintaining the biofilter in continuous adsorptive capacity (8). The main advantages of biofilters compared to physical and chemical remediation are (i) the ability to remove low concentrations of pollutants from large air volumes, (ii) limited maintenance, and (iii) low operation costs (40).…”

“…Although the physical and chemical factors affecting biofilters are fairly well examined (e.g., support material, pH, and moisture conditions), only limited information is available on the biological aspects (8,44). Few molecular studies have provided descriptions of the microbial communities associated with biofilters treating air emissions (14,15,20,52).…”

“…Although the ability to remove a large range of different odor compounds emitted from pig facilities using biofiltration is increasingly used, the microbiology in these filters remains almost unknown (8). The aim of this study was to identify microorganisms involved in the transformation of butyric acid and DMDS in a full-scale biological air filter treating air from a pig facility.…”