Comparison of Five Anaerobic Digestion Systems on Dairy Farms

Wright, Peter E.; Inglis, Scott; Ma, Jing; Gooch, Curt; Aldrich, Brian; Meister, Alex; Scott, Norman R.

doi:10.13031/2013.16760

Cited by 3 publications

(2 citation statements)

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“…The digester produces 32 million L of liquid digestate and 1,800 Mg of solid digestate annually. The solids content of the separated liquid digestate was 4.6% solids, similar to the average total solids content of 5.25% reported by Wright et al (2004) from case studies of five digesters in New York State. Our case study farm returns liquid digestate to annual, perennial, and double-crop fields as a soil amendment and meets 100% of their crop phosphorus needs.…”

Section: Nitrogen and Phosphorussupporting

confidence: 79%

“…We estimated carbon and nutrients in the liquid digestate based on the case study farm's liquid digestate production volume and composition. For the solid digestate, we applied an average solids concentration of 26.6% (Wright et al, 2004) to the measured solids volume and carbon concentration of the solids, estimating the bulk density of the digestate solids based on its total solids content (Wang et al, 2019). Because the digestate solids are recycled to the barn as bedding that again returns to the digester, we closed the digester mass balance on N and P with those recirculating solids.…”

Section: Mass Flows In the Case Studymentioning

confidence: 99%

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Waste to Worth: A Case Study of the Biogas Circular Economy in Pennsylvania

Herbstritt,

Fathel,

Reinford

et al. 2023

Journal of the ASABE

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Highlights The case study farm produces 66% of its biogas from off-farm food waste sources, highlighting the potential to increase the circularity of food and agricultural systems when farms capture and recycle external waste sources. The farm can meet 78% of its crop nitrogen needs from waste products recycled in digestion, assuming a 37% nitrogen use efficiency (NUE). However, phosphorus in the imported food waste creates an excess relative to crop needs. The farm creates an excess of energy that is returned to the electric grid, providing broader off-farm benefits through a circular economy approach. Widespread commercial implementation of circular economy principles in the U.S. dairy sector requires more measured data about how farms successfully implement circularity within the constraints of market incentives and farm operations. Abstract. Coupling agricultural production with sustainable bioenergy systems may help us improve the circular economy of the food system and work within planetary boundaries for climate stabilization. However, leading sustainable dairies often do not have data to support that claim. As a result, practical case studies of circular economies with measured data from commercially operating farms are lacking in the literature, which is instead dominated by hypothetical and theoretical analyses. To grow and scale commercial implementation of circular economy and sustainability principles, it is important to understand how commercial farms implement these principles within the constraints of market incentives and actual farm operations. We conducted a case study of a commercial dairy farm in Pennsylvania, where a well-managed anaerobic digester system serves as the basis for a circular farm economy and allows the next generation to grow the farm business and expand the portfolio of revenue streams. The farm recycles food and agricultural waste into heat, renewable electricity, and fertilizer to heat and power the farm, amend the soil, and reduce farm costs. We also highlight the potential to scale the case study farm's circular economy approach in Pennsylvania using the state's projected 2030 manure, corn stover, winter double crops, switchgrass, and food waste resources to produce energy via biogas or renewable natural gas (RNG). We estimate the state could generate 40 million MJ annually from such integrated anaerobic digestion systems, meeting 3% of its electricity consumption. Circular economies like this case study can be designed in food and agricultural systems to operate within the constraints of an operating farm and recycle waste, produce nitrogen- and phosphorus-rich soil amendments and reduce imports of synthetic fertilizers, reduce and offset fossil energy consumption and greenhouse gas emissions associated with crop and livestock production, regenerate natural ecosystems, help ensure agricultural resilience and sustainability, and provide economic benefits. Keywords: Anaerobic digestion, Biogas, Circular economy, Digestate, Food waste.

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Section: Nitrogen and Phosphorussupporting

confidence: 79%

Section: Mass Flows In the Case Studymentioning

confidence: 99%

Waste to Worth: A Case Study of the Biogas Circular Economy in Pennsylvania

Herbstritt,

Fathel,

Reinford

et al. 2023

Journal of the ASABE

View full text Add to dashboard Cite

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Mechanical Solid-Liquid Manure Separation: Performance Evaluation on Four New York State Dairy Farms - A Preliminary Report

Gooch¹,

Inglis²,

Czymmek³

2005

2005 Tampa, FL July 17-20, 2005

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Five mechanical solid-liquid manure separators manufactured by three different companies and located on four production dairy farms in New York State were sampled monthly from May 2001 to December 2004 (not every separator was sampled continuously throughout this period). Samples were analyzed in an EPA approved commercial laboratory for total solids, total volatile solids, total phosphorus, ortho phosphorus, total Kjeldahl nitrogen, ammonia nitrogen, and potassium. Organic nitrogen was determined by subtraction. The efficiency of capture of each effluent stream was calculated for each constituent analyzed. All separators, regardless of farm specific affects on separation performance, captured no more than 25 percent of the nitrogen and phosphorus in the solid effluent stream. Implications on each farm's CAFO plan were analyzed and the results are presented.

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Digestate and Biogas Cleaning and Processing

Lamb¹

2020

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Through anaerobic digestion, raw biogas is produced. This contains significant amounts of energy-containing methane, but the proportion is much lower than natural gas. In order to allow biogas to be used in specific systems, the raw biogas must be cleaned of impurities, and in some cases upgraded to bio-methane (a renewable natural gas equivalent). In addition, the digest produced from anaerobic digestion, although energy-depleted, has high levels of nutrients that can be beneficially used as a fertiliser. In order to use digestate as a fertiliser, a variety of treatments may be required to prevent hazards. In this chapter, the cleaning of the digestate and raw biogas produced in anaerobic digestion are outlined and discussed.

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Comparison of Five Anaerobic Digestion Systems on Dairy Farms

Cited by 3 publications

References 0 publications

Waste to Worth: A Case Study of the Biogas Circular Economy in Pennsylvania

Waste to Worth: A Case Study of the Biogas Circular Economy in Pennsylvania

Mechanical Solid-Liquid Manure Separation: Performance Evaluation on Four New York State Dairy Farms - A Preliminary Report

Digestate and Biogas Cleaning and Processing

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