Thursday, June 25, 2026

1979 EPA report on Composting utilizing natural chimney effect of heat convection from aerobic microorganisms

 

 https://gaftp.epa.gov/ap42/ch02/s02/reference/ref_02c02s02.pdf

 

 

 

 Sludge is not rendered totally inert by composting. The composting process is
considered complete when the product can be stored without giving
rise to nuisances such as odors, and when pathogenic organisms
have been reduced to a level such that the material can be
handled with minimum risk.

 The aerobic reaction
provides heat for warming the windrows. This causes the air
to rise, producing a natural chimney effect. The rate of air
exchange can be regulated by controlling the porosity and
size of the windrow (2). The turning of the windrow also
introduces oxygen to the microorganisms. 

 

  • Total Biosolids Facilities: There are approximately 280 biosolids composting facilities operating nationwide. [1, 2]
  • Backhus Presence in the U.S.: Eggersmann, the parent company of Backhus, recently celebrated the delivery of its 200th windrow turner to the U.S. market. These machines are deployed across both biosolids and general commercial composting sites
  •  BACKHUS self-propelled windrow turners are widely utilized in large-scale biosolids and sewage sludge compostingFlorida biosolids composting in windrows

     Each
    windrow must be turned two or three times a day
    for the first
    five days to mix the material completely, minimize odors, and
    ens ure suf f ic ient oxygen trans fer. The sl udge is then turned
    once a day for abou t 30 days, depending on weather condi tions.
    Figure 12-5 shows a windrow being turned at Los Angeles

     The forced air method provides for more flexible operation and
    more precise control of oxygen and temperature conditions in
    the pile than would be obtained with a windrow system. Since
    composting times tend to be slightly shorter and anaerobic
    condi tions can be more readily prevented, the risk of odors is
    reduced.
    Two distinct aerated static pile methods have been developed,
    the individual aerated pile and the extended aerated pile.

     The composting and
    all other outdoor operations will take place on a concrete pad
    which is easier to clean than a gravel base, prevents rocks from
    mixing with the compost, and is a better year-round working
    surface. The pad is sloped to allow runoff collection from the
    compost piles. The runoff is recycled to the treatment plant to
    provide protection for the surrounding land and streams. 

     The construction of composting plants has almost ceased in
    European countries other than Sweden. Apparently most
    operating plants have difficulties in marketing the compost
    at a satisfactory price. 

     

     

     https://cwmi.css.cornell.edu/chapter2.pdf

     https://www.biocompost.se/en/solutions/

      “Hauling dewatered biosolids three times a day more than 80 miles was not financially viable, so we explored the possibility of in-vessel composting. Utilizing MSW to supply the carbon side of the composting equation is what led us to start our original plant.” An article in the August 2004 issue of BioCycle (“Expanding The Potential of In-Vessel Composting”) documents the evolution of the Pinetop-Lakeside plant, which started out with a used Eweson digester

     https://www.biocycle.net/mixed-msw-composting-facilities-in-the-u-s/

     canadian biosolids composting

     frozen solid biosolids composting vid

     https://compostsystems.com/new-commercial-compost-facility-ecs-and-pdswm-develop-aerated-composting-system-in-minnesota/

     https://popedouglasrecycle.com/glacial-ridge-compost-facility/

     As a result, the addition of a biolayer cover was written into the EPA regulations governing the static composting of biosolids, and subsequently adopted into many state composting regulations concerning pathogen control.  As biolayer covers became widespread, air quality regulators began to characterize them as pollution control devices; they appear in many air quality permits.  During this evolution, equipment manufacturers such as ECS introduced a series of fabric covers to the market with claims of improving both the composting process and thermal and environmental control (especially control of odor and VOC’s).

     https://compostsystems.com/compost-covers/

     This acts as an insulation layer for pathogen destruction as well as a modest surface biofilter. Biolayer covers need to be at least 6 inches deep to function but are often required to be 12 inches in very cold climates and by some regulators.

     Rynk, Robert et. al. The Composting Handbook:  A how-to and why manual for farm, municipal, institutional, and commercial composters. 2022. Compost Research & Education Foundation.

     

    composting biosolids um which was developed by the USDA at the Belville research station
    sometimes it's called the Bel aat static pile method typically recommended composting

     https://www.youtube.com/watch?v=HZIsnzBnTKQ

     https://www.biocompost.se/en/sustainability/

     

     

     

     

     

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