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Session- Odor Management 

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Influence of Forced Air and Compost Moisture On Mushroom Composting, Odors, Yield and Fresh Quality

 

David M. Beyer (1), R. B. Beelman (2), P. Heinemann (3), K. Lomax (4), T. Rhodes (1) and J. Kremser (1)

 

(1) Dept. of Plant Pathology, Penn State University, (2) Dept. of Food Science, Penn State University, (3) Dept. of Agricultural and Biological Engineering, Penn State University, (4) Dept. of Bioresource Engineering, University of Delaware, USA

 

Mushroom composting operations today have adopted forced-air Phase I composting systems because of neighboring community pressure that could result in strict air quality regulations. Research is needed to determine the operating parameters for indigenous bulk ingredients and to determine if the biology/chemistry of the process can be improved. Experiments were carried out to compare changes in composting dry matter, oxygen, temperature and moisture content of standard windrow mushroom composting with that of forced aerated composting. Odors produced from different compost formulae and aeration schemes were measured. Compost procedures were altered to determine how higher compost moisture would perform using forced aeration. Standard moisture level compost with aeration had higher oxygen levels after the second turn compared to the rick and wet aerated composts. Windrow temperatures were higher during the early Phase I, however later the standard rick and normal aerated compost temperatures were similar.  Increased quantities of gypsum did not seem to increase the intensity or reduce pleasantness of the odors produced. Little difference in organic matter loss between the compost was noted; total shrink was slightly higher for the wet aerated composts. The different moisture and aerated composts showed no significant difference in yield by break and total yield. Compost moisture did not influence fresh mushroom solids, initial whiteness or color.

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Volatile Organic Compounds Emissions During the Composting of Biosolids From A Domestic Waste Water Treatment Plant

 

Sandra  L. ESTEVEZ (1), Claudia X. Ramos (2), and Eugenio Giraldo(3).

 

(1-3) Environmental Engineering Research Center, Civil & Environmental Engineering Department, University of Los Andes. A.A. 4976. Bogot¡. Colombia., Colombia

 

"El Salitre" a municipal waste water treatment plant has been constructed to handle a part of the domestic waste waters generated in Bogota that are finally incorporated to the Bogota river (the pollutest river of the country).  Biosolids volume generated during the wastewater treatment can reach 135 tons/day. Biosolids composting become into an alternative to these solid waste management: However, a large amount of toxic, hazardous  (the waste water treated by the "El Salitre" plant is a mixture of domestic and industrial ones) and malodorous  gases and vapors are emitted from the biosolids. Volatile organic compounds (VOCs) emitted by two static piles of composting of biowastes coming from of "El Salitre" wastewater treatment plant were analyzed.  Each pile in its sampling time was stayed with a different aeration system. The sampling was made using Solid Phase Microextraction (SPME) with  separation and analysis by Gas Chromatography (GC) coupled to Mass Spectrometry (MS). The VOCs emission behavior varied according  to the aeration system used. SPME enables the acquisition of VOC concentration data during a composting process, low sample requirements and sensibility are some of the advantages of this technique over other conventional VOC sampling methodologies.  Temperature plays an important role in the VOCs emission during the composting process. The increasing on temperature assure a good quality compost, but favor the volatilization of VOC that in most cases are toxic or malodorous such as it was observed in the no-aerated pile where the highest temperature (52oC) were reached by a shorter period (6 days) compared with the VOC emission levels and maximum temperature showed by the negatively aerated pile. 154 different organic compounds were identified in the composting pile emissions, from this 14 are regulated by U.S. EPA because its toxicity by ingestion or inhalation and some of the are suspected to cause cancer.

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An Alternative Strategy to Reduce Odor Nuisance From Biowaste Composting

 

LYSTAD, HENRIK (1), Hammer, Jan P. (2), S¸rheim, Roald (1), Molland, Ove (1), Smits, P (2)

 

(1) Jordforsk Norwegian Centre for Soil and Environmental Research, N-1432 s, Norway, (2) Lindum Ressurs og Gjenvinning KB, N-3036 Drammen, Norway, Norway

 

The regional Norwegian waste company Lindum Ressurs og Gjenvinning KB has composted source-separated biowaste from households since 1997.  Traditional composting with shredded yard waste as bulking agent, initially in windrows and later in a closed reactor, led to severe odor nuisance. The situation was characterized by low pH during the process and high emissions of fatty acids and other volatile organic compounds (VOC). Similar observations has been reported from other composting facilities in Norway, possibly due to a high content of meat and fish in the Norwegian biowaste and an unfavorable microbial population. In 1998 the company developed a new strategy to reduce the odor nuisance and improve the composting process. The strategy is to rise the pH and to sanitize the biowaste before the microbial population of the bulking agent is introduced. The method is based on a new feed mix where lime is mixed with shredded biowaste prior to mixing with a biological active bulking agent. Measurements of odor emissions from the intensive phase of the composting process show a decrease of 91 %, expressed as VOC, compared to the traditional method. The compost was found to be stable, Rottegrad IV/V, after only 14-21 days. The finished compost has been approved for use in ecological farming. Microbial studies indicate that the microbial population in the waste is reduced by an order of 2-3 when lime is added. After only two days of full scale composting, the microbial population was above 1010 cfu/g DM and the pH had declined to a normal level. The novel composting strategy has successfully reduced the odor nuisance and improved the composting process at Lindum. The treatment capacity has been increased and the deterioration of reactor equipment by corrosion has been reduced. The strategy is applicable for all kinds of composting technology, where low pH and VOC emissions represent a problem.