AD Support

Solution Strengths, Weaknesses and Critical Indicators

Anaerobic Digester Associated Technology:

NOTE: There are several technology types that are used as part of an integrated manure management system that includes an anaerobic digester and are not applicable to manure management in other cases. The impact of these technologies on the critical indicators are represented as those of an entire anaerobic digester system.

   

  • Long usable life and can be run reliably
  • Creates energy and generates environmental credits
  • Requires proper preparation of the feedstock
  • Requires other technologies for energy utilization
  • Requires other technologies for digestate handling
  • Proper feeding & system monitoring is required to avoid system downtime
  • Proven technology for odor control, GHG reduction and pathogen reduction

Overall Summary

 Primary Application

  • Dairy farms with over 500 cows or farms with meaningful organics for co-digestion.
  • Vacuumed/scraped manure, manure slurries, bedded pack that is diluted with digester effluent.

 Economic/Return on Investment Considerations

  • Economics are almost always a challenge; on a value of renewable energy basis, AD is hard to justify, at present received prices for electricity and gas.
  • AD does provide several non-monetary benefits to a farm (see below).

 Industry Uptake

  • 200 dairy-based U.S. installations and thousands worldwide.

Technology Maturity

  • Refined, standard designs available from multiple technology providers.

Primary Benefits

  • Odor reduction – 70 to 95% reduction of indicator acids.
  • Manure organic matter reduction – 35%.
  • Renewable electrical energy production – 2,000 kWh/cow possible each year.
  • Pathogen reduction – 90%+ elimination of fecal coliform organisms as a typical indicator pathogen.
  • Greenhouse gas emission reduction – amount varies by location and farm-specific, but reductions can be large, on the order of 67%+.
  • Nutrient preservation/transformation – key crop nutrients in manure are not consumed by AD and the nutrient form is more plant available than when not digested.
  • Contributes to society’s goal for organic landfill diversion – co-digestion easily achieved enhancing above benefits.

Secondary Benefits

  • Pre-treatment for tertiary treatments like ammonia stripping.
  • Renewable thermal heat production – 13,500 Btu’s/cow or more possible each year.
  • Less impact on water quality.
  • Increased crop yields possible.

How it Works

  • Raw or pre-treated manure is conveyed into a gas tight vessel on a regular basis (daily or more often) that operates at a set temperature (38 ⁰C in most cases).
  • Naturally occurring microbes in manure break solids down into energy-rich biogas.
  • Biogas is used to fuel engine-generators to make electricity or is cleaned to make a natural gas replacement.
  • Some of the produced gas, or heat produced by an engine-generator set is used to heat the digester making it a net energy production system.

 Pre-treatment and/or Post-treatment Required

  • Pre-treatment not required when organic material is used to bed stalls and/or when manure is not substantially diluted. Pre-treatment to remove bedding sand is required with sand-bedded stalls.
  • Pre-treatment may be used to remove excess moisture from influent from barns were hydraulic flushing is used.
  • Post-treatment not required but may be employed based on overall goals of the manure treatment system.

Limitations

  • Does not reduce volume.
  • Does not work well with raw manure containing bedding sand.
  • Does not work with highly diluted manure due to cost and heat demands for a large vessel.

Other Considerations

  • Currently, most systems are farmer managed, more consistent results may be achieved by dedicated operators.

Solutions Providers in order of 9-Point Scoring System

NOWON is the United States base of manufacturing, operation, marketing, and distribution for ECONWARD TECH, its Spanish sister company. A Cutting-Edge Technology For Waste Treatment Facilities Since ECONWARD was founded, it has invested about 80% of its resources in research and development, to build a highly efficient and internationally competitive…
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Peoples Gas is invested in diverse energy solutions to serve the growing needs of Floridians. They currently are participating in three RNG projects which will provide a clean pathway to meaningful reduction in greenhouse gas emissions for the state. In 2017, the Florida Public Service Commission (PSC) approved our RNG…
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Qnergy’s Free Piston Stirling Engine is 3rd party tested to provide 100% methane destruction and a GHG emissions profile >10X better than EPA standards. It’s linear motor design has no rotating parts and no lubricants. Rated for 80,000 hours of continuous service with no required scheduled maintenance. The PowerGen can…
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Biogas production and consumption are increasing in a world concerned with both the cost of energy and the environmental impact of energy production and waste disposal. Biogas production facilities, like digesters, landfills and wastewater treatment plants require robust equipment to handle the wet, acidic gas produced. Organic Waste Digester One…
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NES AND WES bring over 50 years’ experience in reciprocating engine power applications, engineering and product support. They provide integrated Combined Heat and Power solutions which are cost effective, highly efficient, and environmentally friendly. Their customers benefit from reliable solutions which provide energy savings, energy resiliency, and carbon footprint reduction.
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Methagen AD is a system, based on VPSA (Vacuum Pressure Swing Adsorption) technology designed to purify biogas from Anaerobic Digestion feedstock like: Wastewater treatment plants Food and organic municipal waste Agricultural waste The Methaboost option is a post-treatment stage based on Vaccum Swing Adsorption (VSA) technology enabling the recovery of…
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Cogeneration, or CHP, is the simultaneous production of electric and thermal energy from a single fuel source. CHP can provide thermal energy in the form of steam, hot water, chilled water or space heating. There are different CHP options to properly serve the electric and thermal load profile of the…
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Heat exchangers are an essential part of a biogas plant and Bigadan specializes in customized countercurrent heat exchangers for biogas plants and sludge treatment. The heat exchangers are designed by Bigadan especially for biomass and have the following documented characteristics: Large capacity: 35-40 m³/h Minimum loss of pressure Excellent heat…
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ANGI Energy Systems LLC, designs and manufactures custom designed fueling systems for natural gas vehicles. The foundation of these fueling systems is a compressor that increases the inlet gas pressure, typically utility supplied, to fuel vehicles. Their standard reciprocating compressors produce flows from 50 to 6,000 scfm and employ drivers…
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Brown and Caldwell focuses on efficient cost effective design and construction to deliver renewable natural gas (RNG) facilities that maximize uptime and minimize long-term maintenance. RNG is a carbon neutral, versatile fuel that is fully compatible with existing pipelines and infrastructure. It is generated by anaerobically turning biogas from animal…
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