Wednesday, June 12, 2024

Process to Further Reduce Pathogens (PFRP): minimum of Six months for Class A thermophilic sludge biosolid aerobic bacteria composting: 1.5 to 1 ratio of carbon to dewatered biosolids

 https://www.sludgeprocessing.com/aerobic-digestion/sludge-composting/

May 8, 2020The process takes around six months. The materials for combining with sludge prior to composting are categorised as either bulking agents or ...

https://compostsystems.com/biosolids-composting/ 

 

 When we talk about the bioavailability of carbon, we are referring to how available the carbon for bio-oxidation by the aerobic bacteria during active composting (typically the first 3 weeks).  Much of the plant-based carbon is in the form of lignocelluloses (reference paper) which can be broken down over a period of months by a broad spectrum of fungi and bacteria to form humic compounds; too slowly to significantly add to the active phase bioavailability of carbon.  Fortunately, all ground plant material has some available carbon on the surfaces of the particles, but it is not all equal to the microbes. The fresher the material and the finer the particle size, the more bioavailable carbon tends to be present.  For example, a freshly chipped tree provides much more bio-available carbon than a sun-weathered and chipped pallet. Chipped or shredded wood offers much more structure than paper or leaves.

 The two basic field tests are the 5 gallon bucket density test and the squeeze moisture test.  These articles describe the two tests:  density and squeeze.  We recommend that operators conduct and record these tests a couple of times every day while creating the mix.  This enables operators to adjust mix ratios on the fly to maintain target density and moisture levels.

 In summary, when designing any compost mix, the process engineer should evaluate for BMP compliance:

  • carbon/nitrogen ratio
  • moisture
  • bulk density

Often this results in at least a 1:1 or 1.5:1 ratio of woody biomass to dewatered biosolids (by wet weight).

https://harvestquest.com/biosolids/

 

USING BIOSOLIDS FOR RECLAMATION/REMEDIATION ...

PDF
by S BrownCited by 9Composting is often a portion of a municipalities biosolids program. Composting biosolids requires a long residence time (1-4 months).

 https://www.epa.gov/sites/default/files/2015-05/documents/biosolidswhitepaper-uwash.pdf

 Salish Soils

The entire compost process takes a minimum of 6 months to achieve Class A compost. The Biosolids Compost is used to make Bio soil which is mixture of ...

 After transported to Salish Soils site, the biosolids are prepared for the composting process to create Class A compost. After being mixed with the proper amount of carbon and water, the mixture is placed in aerated channels and covered with a membrane utilizing Gore technology. The carbon source is from ground up Green Waste dropped off at Salish Soils from residential and commercial customers.

The mixture is constantly monitored, and the air flow is adjusted to reach OMRR (Organic Matter Recycling Regulation of British Columbia) guidelines of 55°C for a minimum of three days to kill weed seeds and pathogens. The mixture is flipped after 2 weeks to reintroduce oxygen, and if required, additional water is added. After an additional 2 weeks, the mixture is removed from the bay and placed in curing piles for a minimum of 5 months. After curing, the mixture is screened to remove the larger woody material, and any other potential contamination that may have been introduced, and is now ready to be sold. The entire compost process takes a minimum of 6 months to achieve Class A compost.

 https://www.biocycle.net/building-longevity-into-biosolids-composting-operation/

 

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