Olfactory Response to Mushroom Composting Emissions as a Function of Chemical Concentration

Abstract

Odor pollution is a major problem facing mushroom [Agaricus bisporus (Lange) Imbach] compost production. Techniques for quantifying mushroom composting odors are needed to assess the effectiveness of odor control measures. Odor samples were obtained in nalophane bags from 11 mushroom composting sites. Samples were collected 0.2 m downwind from the pre-wetting heaps (aerated or unaerated) of raw composting ingredients (wheat straw, poultry and horse manures, and gypsum) and subsequent Phase I composting windrows or aerated tunnels. The odor concentrations (OCs) of the samples were assessed using serial dilution olfactometry and the chemical composition of the samples was determined using gas chromatography-mass spectrometry (GC-MS), both 24 h after sampling. Gas detector tubes were used for on-site measurement of gaseous compounds. Odorants that exceeded their published olfactory detection thresholds by the greatest order of magnitude, in decreasing order, were: H2S, dimethyl sulfide (DMS), butanoic acid, methanethiol, and trimethylamine. Concentrations of NH3 were not significantly correlated with OC, and they were not significantly affected by the use of aeration. Aeration reduced the OC and the combined H2S + DMS concentrations by 87 and 92%, respectively. There was a very close correlation (r = 0.948, P < 0.001) between the OC of bag samples and the combined H2S + DMS concentrations, measured on-site with detector tubes. This relationship was unaffected by the NH3 concentration or the type of compost: aerated or unaerated, pre-wet or Phase I, poultry manure-based or horse and poultry manure-based compost. Prediction of the OC will enable rapid and low-cost identification of odor sources on mushroom composting sites.

Effects of pH and microbial composition on odour in food waste composting

“…Organic acids have received relatively little attention in compost odour research. Nevertheless, acids have been reported in research on odour from mushroom composting (Noble et al, 2001) and composting of food waste in combinations with other substrates (Gallego et al, 2012; Krzymien et al, 1999; Komilis et al, 2004; Mao et al, 2006; Tsai et al, 2008). None of these authors, however, reported acids to be a major component of odour, and unfortunately they did not report pH or organic acid concentrations in compost samples.…”

Yield, size, and mushroom solids content of Agaricus bisporus produced on non-composted substrate and spent mushroom compost

“…A combination of sub-urbanization and the heightened sensitivity of the general population to environmental issues have focused public attention on these issues (Kelsey and Singletary 1997;Duns et al 2004). Growers have adopted several measures to reduce the environmental impact of mushroom farming, including the practice of forced aeration of Phase I compost contained in bunkers or tunnels (Op den Camp et al 1991;Noble et al 2001) and the development of new uses for SMC (AMI 2005;Davis and Kuhns 2005). However, the issues of offensive odor generation and SMC disposal continue to place severe pressure on mushroom growers.…”

A survey of ammonia-assimilating micro-organisms in cattle manure composting

“…2002, 2004). In particular, studies on nitrogen metabolism in mushroom compost have focused on ammonia assimilation (Noble et al. 2001; Vane et al.…”

“…Ammonia assimilation by micro-organisms is considered to be one of the important steps for the removal of ammonia from manure treatment systems (Nakai et al 1999;Sasaki et al 2002Sasaki et al , 2004. In particular, studies on nitrogen metabolism in mushroom compost have focused on ammonia assimilation (Noble et al 2001;Vane et al 2001;Noble et al 2002), and together with the ammonia assimilatory pathway of Agaricus bisporus, these nitrogen metabolism pathways have been well characterized Schaap et al 1996Schaap et al , 1997. Although many species of micro-organisms are known to assimilate ammonia through glutamine synthesis (Merrick and Edwards 1995;Patriarca et al 2002), details of the distribution and function of ammonia-assimilating micro-organisms in the composting process have not yet been clarified.…”