Integrated experimental and techno-economic modeling of RNG production from prairie biomass

Author(s): Elmin Rahic, Nicholas Cassady, Cooper Hess, Mark Mba-Wright, Juliana Vasco-Correa, Zhiyou Wen

Abstract:

This study coupled experimental and techno-economic modeling to evaluate the economic prospects of utilizing prairie biomass as a feedstock for anaerobic digestion. In addition to evaluating key anaerobic digestion parameters, four scenarios were evaluated investigating liquid digestate recirculation, as well as methane recovery from the liquid digestate in a two-stage anaerobic digestion process.

Funder: USDA NIFA

Award Title:

Consortium for Cultivating Human And Naturally reGenerative Enterprises: Grass2Gas

Award Number: 2020-68012-31824

Keywords:

BioSTEAM, anaerobic digestion, liquid digestate recirculation, prairie biomass, techno-economic assessment

Project (Abbreviated name):

G2G_Wen_anaerobic_digestion_TEA

Team: Grass2Gas

Geographic Location:

The state of Iowa

Families:

Bovidae

Species:

Bos taurus

Full Metadata:

Metadata for G2G_Wen_anaerobic_digestion_TEA.pdf (505.04 KB)

Data Mirror:

Data Table Column Names and Descriptions

Table Name	Column Name	Data Type	Units	Column Description
data.dataset_manure_and_biomass_composition	dataset manure and biomass composition pkey	integer	dimensionless	A unique primary key for this table.
data.dataset_manure_and_biomass_composition	manure	float	NA	Beef cattle manure obtained from a beef farm in Kingsley, Iowa.
data.dataset_manure_and_biomass_composition	parameter	string	NA	The parameter whose value is listed in the manure or prairie column. See code details in the following code definition table.
data.dataset_manure_and_biomass_composition	prairie	float	NA	Mixed prairie biomass obtained from COBS sites and harvested in November.
data.dataset_manure_and_biomass_composition	unit	string	NA	The unit of the parameter.
data.dataset_phase_one_no_recirculation	Ave Biogas Yield	float	milliliter	The mean daily biogas yield per gram of volatile solids fed in the prescribed prairie to manure ratio.
data.dataset_phase_one_no_recirculation	Ave CH4 Content	float	NA	The mean proportion of methane across biogas samples.
data.dataset_phase_one_no_recirculation	Ave CH4 Yield	float	milliliter	The mean daily methane yield per gram of volatile solids fed in the prescribed prairie to manure ratio.
data.dataset_phase_one_no_recirculation	Grass Ratio	float	NA	Prarie-to-manure ratio. Mass of prairie biomass fed to the reactors relative to the mass of manure fed to the reactors. On a volatile solids-to-volatile solids basis.
data.dataset_phase_one_no_recirculation	HRT	float	NA	Hydraulic retention time of the reactors. How long the feedstocks were being digested, on average, in continuously mixed systems.
data.dataset_phase_one_no_recirculation	LD BG Potential	float	NA	Biogas potential of the liquid digestate samples. The total amount of biogas that can be produced from the liquid digestate as-is, expressed in terms of mL/gVS.
data.dataset_phase_one_no_recirculation	LD CH4 Potential	float	NA	Methane potential of the liquid digestate samples. The total amount of methane that can be produced by the liquid digestate as-is. Expressed in terms of mL/gVS.
data.dataset_phase_one_no_recirculation	LD Fertilizer Value	float	NA	The liquid digestate is valued based on its fertilizer value considering nitrogen, phosphorus, and potassium concentrations. The nitrogen was valued at $1.06/kg, phosphorus at $1.78/kg, and potassium at $1.21/kg (Myers et al., 2022; Schnitkey et al., 2022).
data.dataset_phase_one_no_recirculation	LD NH3	float	milligramPerLiter	Ammonia concentration in the liquid digestate.
data.dataset_phase_one_no_recirculation	LD RP	float	milligramPerLiter	The concentration of reactive phosphorus in the liquid digestate.
data.dataset_phase_one_no_recirculation	LD TK	float	milligramPerLiter	The concentration of total potassium in the liquid digestate.
data.dataset_phase_one_no_recirculation	LD TN	float	milligramPerLiter	The concentration of total nitrogen in the liquid digestate.
data.dataset_phase_one_no_recirculation	LD TP	float	milligramPerLiter	The concentration of total phosphorus in the liquid digestate.
data.dataset_phase_one_no_recirculation	LD TS	float	NA	The proportion of solids by weight of the liquid digestate.
data.dataset_phase_one_no_recirculation	LD VS	float	NA	The proportion of volatile solids of the liquid digestate by weight.
data.dataset_phase_one_no_recirculation	MFA LD C	float	NA	Mass flow analysis (mass balance) estimate of how much carbon went to the liquid digestate.
data.dataset_phase_one_no_recirculation	MFA LD K	float	NA	Mass flow analysis (mass balance) estimate of how much potassium went to the liquid digestate.
data.dataset_phase_one_no_recirculation	MFA LD N	float	NA	Mass flow analysis (mass balance) estimate of how much nitrogen went to the liquid digestate.
data.dataset_phase_one_no_recirculation	MFA LD P	float	NA	Mass flow analysis (mass balance) estimate of how much phosphorus went to the liquid digestate.
data.dataset_phase_one_no_recirculation	MFA SD C	float	NA	Mass flow analysis (mass balance) estimate of how much carbon went to the solid digestate.
data.dataset_phase_one_no_recirculation	MFA SD K	float	NA	Mass flow analysis (mass balance) estimate of how much potassium went to the solid digestate.
data.dataset_phase_one_no_recirculation	MFA SD N	float	NA	Mass flow analysis (mass balance) estimate of how much nitrogen went to the solid digestate.
data.dataset_phase_one_no_recirculation	MFA SD P	float	NA	Mass flow analysis (mass balance) estimate of how much phosphorus went to the solid digestate.
data.dataset_phase_one_no_recirculation	Organic Load	float	NA	The concentration of organic material fed to the reactors every other day. Expressed as % volatile solids, ranging from 5 - 10% (50 - 100 gVS/L)
data.dataset_phase_one_no_recirculation	Reactor ID	integer	dimensionless	The designation for the bench-scale reactor that provided the starting material.
data.dataset_phase_one_no_recirculation	SD Carbon	float	percent	The total carbon percentage of the solid digestate.
data.dataset_phase_one_no_recirculation	SD Nitrogen	float	percent	The total nitrogen percentage of the solid digestate.
data.dataset_phase_one_no_recirculation	SD Phosphorus	float	percent	The total phosphorus percentage of the solid digestate.
data.dataset_phase_one_no_recirculation	SD Potassium	float	percent	The total potassium percentage of the solid digestate.
data.dataset_phase_one_no_recirculation	SD TS	float	NA	The proportion of solids by weight of the solid digestate.
data.dataset_phase_one_no_recirculation	SD VS	float	NA	The proportion of volatile solids of the solid digestate by weight.
data.dataset_phase_one_no_recirculation	SD VS Split	float	NA	The solid-liquid separation efficiency of the dewatering process for the digestate samples. The proportion of the volatile solids (after digestion) that were separated to the solid digestate stream.
data.dataset_phase_one_no_recirculation	dataset phase one no recirculation pkey	integer	dimensionless	A unique primary key for this table.
data.dataset_phase_one_no_recirculation	pH	float	dimensionless	The pH of the liquid fraction of the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	Ave Biogas Yield	float	milliliter	The mean daily biogas yield per gram of volatile solids fed in the prescribed prairie to manure ratio.
data.dataset_phase_two_50_percent_recirculation	Ave CH4 Content	float	NA	The mean proportion of methane across biogas samples.
data.dataset_phase_two_50_percent_recirculation	Ave CH4 Yield	float	milliliter	The mean daily methane yield per gram of volatile solids fed in the prescribed prairie to manure ratio.
data.dataset_phase_two_50_percent_recirculation	Fertilizer Value	float	NA	The liquid digestate is valued based on its fertilizer value considering nitrogen, phosphorus, and potassium concentrations. The nitrogen was valued at $1.06/kg, phosphorus at $1.78/kg, and potassium at $1.21/kg (Myers et al., 2022; Schnitkey et al., 2022).
data.dataset_phase_two_50_percent_recirculation	Grass Ratio	float	NA	Prarie-to-manure ratio. Mass of prairie biomass fed to the reactors relative to the mass of manure fed to the reactors on a volatile solids-to-volatile solids basis.
data.dataset_phase_two_50_percent_recirculation	HRT	float	NA	Hydraulic retention time of the reactors. How long the feedstocks were being digested, on average, in continuously mixed systems.
data.dataset_phase_two_50_percent_recirculation	LD 35C 10day BG	float	NA	Biogas production from liquid digestate incubation experiments after 10 days of incubation at 35 degrees Celcius.
data.dataset_phase_two_50_percent_recirculation	LD 35C 10day CH4	float	NA	Methane production from liquid digestate incubation experiments after 10 days of incubation at 35 degrees Celcius.
data.dataset_phase_two_50_percent_recirculation	LD 35C 20day BG	float	NA	Biogas production from liquid digestate incubation experiments after 20 days of incubation at 35 degrees Celcius.
data.dataset_phase_two_50_percent_recirculation	LD 35C 20day CH4	float	NA	Methane production from liquid digestate incubation experiments after 20 days of incubation at 35 degrees Celcius.
data.dataset_phase_two_50_percent_recirculation	LD 35C 30day BG	float	NA	Biogas production from liquid digestate incubation experiments after 30 days of incubation at 35 degrees Celcius.
data.dataset_phase_two_50_percent_recirculation	LD 35C 30day CH4	float	NA	Methane production from liquid digestate incubation experiments after 30 days of incubation at 35 degrees Celcius.
data.dataset_phase_two_50_percent_recirculation	LD NH3	float	milligramPerLiter	Ammonia concentration in the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	LD RP	float	milligramPerLiter	The concentration of reactive phosphorus in the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	LD TK	float	milligramPerLiter	The concentration of total potassium in the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	LD TN	float	milligramPerLiter	The concentration of total nitrogen in the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	LD TP	float	milligramPerLiter	The concentration of total phosphorus in the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	LD TS	float	NA	The proportion of solids by weight of the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	LD VS	float	NA	The proportion of volatile solids of the liquid digestate by weight.
data.dataset_phase_two_50_percent_recirculation	LD VStoTS	float	NA	The proportion of volatile solids within the total solids fraction of the liquid digestate.
data.dataset_phase_two_50_percent_recirculation	Organic Load	float	NA	The concentration of organic material fed to the reactors every other day. Expressed as % volatile solids, ranging from 5 - 10% (50 - 100 gVS/L)
data.dataset_phase_two_50_percent_recirculation	Reactor ID	integer	dimensionless	The designation for the bench-scale reactor that provided the starting material.
data.dataset_phase_two_50_percent_recirculation	SD Carbon	float	percent	The total carbon percentage of the solid digestate.
data.dataset_phase_two_50_percent_recirculation	SD Nitrogen	float	percent	The total nitrogen percentage of the solid digestate.
data.dataset_phase_two_50_percent_recirculation	SD Phosphorus	float	percent	The total phosphorus percentage of the solid digestate.
data.dataset_phase_two_50_percent_recirculation	SD Potassium	float	percent	The total potassium percentage of the solid digestate.
data.dataset_phase_two_50_percent_recirculation	SD TS	float	NA	The proportion of solids by weight of the solid digestate.
data.dataset_phase_two_50_percent_recirculation	SD VS	float	NA	The proportion of volatile solids of the solid digestate by weight.
data.dataset_phase_two_50_percent_recirculation	SD VS Split	float	NA	The solid-liquid separation efficiency of the dewatering process for the digestate samples. The proportion of the volatile solids (after digestion) that were separated to the solid digestate stream.
data.dataset_phase_two_50_percent_recirculation	SD VStoTS	float	NA	The volatile solids proportion of the total solids in the solid digestate.
data.dataset_phase_two_50_percent_recirculation	dataset phase two 50 percent recirculation pkey	integer	dimensionless	A unique primary key for this table.
data.dataset_phase_two_50_percent_recirculation	pH	float	dimensionless	The pH of the liquid fraction of the liquid digestate.
data.linear_biogas_methane_proportion_raw	linear biogas methane proportion raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_biogas_methane_proportion_raw	methane proportion mean	float	NA	The mean proportion of methane across all ten biogas samples.
data.linear_biogas_methane_proportion_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_biogas_methane_proportion_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor that provided the starting material.
data.linear_biogas_methane_proportion_raw	sample 1	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 10	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 2	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 3	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 4	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 5	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 6	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 7	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 8	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_methane_proportion_raw	sample 9	float	NA	The proportion of methane in the biogas sample taken at this occasion. Samples were taken every other day.
data.linear_biogas_yield_raw	linear biogas yield raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_biogas_yield_raw	mean biogas yield ml per g vs	float	milliliter	The mean daily biogas yield per gram of volatile solids fed in the prescribed prairie to manure ratio.
data.linear_biogas_yield_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_biogas_yield_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.linear_biogas_yield_raw	sample 1	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 10	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 11	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 12	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 13	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 14	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 15	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 16	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 17	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 18	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 19	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 2	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 20	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 21	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 22	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 23	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 24	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 25	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 26	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 27	integer	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 28	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 29	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 3	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 30	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 31	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 32	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 33	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 34	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 35	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 4	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 5	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 6	integer	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 7	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 8	float	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	sample 9	integer	milliliter	The volume of biogas produced by the reactor since the previous sampling and feeding date (every 48 hours). Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.linear_biogas_yield_raw	total daily volatile solids added g	float	gram	The assigned daily total volatile solids added, in the prairie to manure ratio listed in data.dataset_phase_one_no_recirculation. Volatile solids additions were prescribed on a daily basis, but fed in twice that amount every two days.
data.linear_digestate_liquid_ammonia_raw	dilution	float	number	The number of times the sample was diluted before testing.
data.linear_digestate_liquid_ammonia_raw	linear digestate liquid ammonia raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_digestate_liquid_ammonia_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_digestate_liquid_ammonia_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.linear_digestate_liquid_ammonia_raw	reading	float	milligramPerLiter	Ammonia concentration reading from Hach Spectrophotometer. Sample processing done with Hach TNT test kit.
data.linear_digestate_liquid_ammonia_raw	sample	integer	dimensionless	The sample replicate. Reactors were randomly selected on distributed days during the steady state portions of the experimental timeline.
data.linear_digestate_liquid_ammonia_raw	test substance	string	NA	The material being tested.
data.linear_digestate_liquid_ammonia_raw	true concentration mg per l	float	milligramPerLiter	The concentration of ammonia in the sample determined by multiplying the reading by the dilution.
data.linear_digestate_liquid_ammonia_raw	true concentration mg per l mean	float	milligramPerLiter	The mean true concentration of ammonia across all samples.
data.linear_digestate_liquid_ph_raw	linear digestate liquid ph raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_digestate_liquid_ph_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_digestate_liquid_ph_raw	ph mean	float	NA	The mean pH of the liquid fraction of the liquid digestate across sampling occasions.
data.linear_digestate_liquid_ph_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.linear_digestate_liquid_ph_raw	sample 1	integer	NA	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.linear_digestate_liquid_ph_raw	sample 2	float	NA	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.linear_digestate_liquid_ph_raw	sample 3	float	NA	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.linear_digestate_liquid_ph_raw	sample 4	float	NA	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.linear_digestate_liquid_ph_raw	sample 5	float	NA	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.linear_digestate_liquid_ph_raw	sample 6	float	NA	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.linear_digestate_liquid_ph_raw	test substance	string	NA	The material being tested.
data.linear_digestate_liquid_total_nitrogen_raw	dilution	float	number	The number of times the sample was diluted before testing.
data.linear_digestate_liquid_total_nitrogen_raw	linear digestate liquid total nitrogen raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_digestate_liquid_total_nitrogen_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_digestate_liquid_total_nitrogen_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.linear_digestate_liquid_total_nitrogen_raw	reading	float	milligramPerLiter	Nitrogen concentration reading from Hach Spectrophotometer. Sample processing done using Hach TNT test kit.
data.linear_digestate_liquid_total_nitrogen_raw	sample	integer	dimensionless	The sample replicate. Samples were chosen on randomly assigned days during the steady state period.
data.linear_digestate_liquid_total_nitrogen_raw	test substance	string	NA	The material being tested.
data.linear_digestate_liquid_total_nitrogen_raw	total nitrogen mg per l	float	milligramPerLiter	The total concentration of organic and inorganic nitrogen after multiplying the reading by the dilution.
data.linear_digestate_liquid_total_nitrogen_raw	total nitrogen mg per l mean	float	milligramPerLiter	The mean total nitrogen concentration across samples.
data.linear_digestate_liquid_total_phosphorus_raw	dilution	float	number	The number of times the sample was diluted before testing.
data.linear_digestate_liquid_total_phosphorus_raw	linear digestate liquid total phosphorus raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_digestate_liquid_total_phosphorus_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_digestate_liquid_total_phosphorus_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.linear_digestate_liquid_total_phosphorus_raw	reading	float	milligramPerLiter	Phosphorus concentration reading from Hach Spectrophotometer. Sample processing done using Hach TNT 844 test kit.
data.linear_digestate_liquid_total_phosphorus_raw	sample	integer	dimensionless	The sample replicate. Samples were chosen on randomly assigned days during the steady state period.
data.linear_digestate_liquid_total_phosphorus_raw	test substance	string	NA	The material being tested.
data.linear_digestate_liquid_total_phosphorus_raw	total phosphorus mg per l	float	milligramPerLiter	The total phosphorus concentration after multiplying the reading by the dilution.
data.linear_digestate_liquid_total_phosphorus_raw	total phosphorus mg per l mean	float	milligramPerLiter	The mean total phosphorus concentration across samples.
data.linear_digestate_solid_tc_tn_raw	linear digestate solid tc tn raw pkey	integer	dimensionless	A unique primary key for this table.
data.linear_digestate_solid_tc_tn_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.linear_digestate_solid_tc_tn_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.linear_digestate_solid_tc_tn_raw	sample	integer	dimensionless	The sample replicate. Samples were chosen on randomly assigned days during the steady state period.
data.linear_digestate_solid_tc_tn_raw	test substance	string	NA	The material being tested.
data.linear_digestate_solid_tc_tn_raw	total carbon pct	float	percent	The percentage of the sample composed of carbon by weight.
data.linear_digestate_solid_tc_tn_raw	total carbon pct mean	float	percent	The mean total carbon across samples.
data.linear_digestate_solid_tc_tn_raw	total nitrogen pct	float	percent	The percentage of the sample composed of nitrogen by weight.
data.linear_digestate_solid_tc_tn_raw	total nitrogen pct mean	float	percent	The mean total nitrogen across samples.
data.phase_one_digestate_incubations_raw	crucible g	float	gram	The weight of the crucible.
data.phase_one_digestate_incubations_raw	crucible plus ash g	float	gram	The weight of the crucible plus ash after volatilizing in a muffle furnace.
data.phase_one_digestate_incubations_raw	crucible plus dry digestate g	float	gram	The weight of the crucible plus the digestate after drying at 104 degrees Celcius.
data.phase_one_digestate_incubations_raw	crucible plus wet digestate g	float	gram	The weight of the crucible plus the wet digestate sample.
data.phase_one_digestate_incubations_raw	day	integer	number	Days since incubation start.
data.phase_one_digestate_incubations_raw	initial substrate g	float	gram	The weight of the initial incubation material, taken from the named reactor during steady-state of phase one.
data.phase_one_digestate_incubations_raw	initial substrate solids g	float	gram	The weight of solids in the initial incubation material derived from the starting weight and the percent solids calculated from source.
data.phase_one_digestate_incubations_raw	initial volatile solids g	float	gram	The weight of volatile solids in the initial inubation materials, based on calculations made with the source material.
data.phase_one_digestate_incubations_raw	phase one digestate incubations raw pkey	integer	dimensionless	A unique primary key for this table.
data.phase_one_digestate_incubations_raw	product	string	NA	The gas being measured by volume_mL.
data.phase_one_digestate_incubations_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor that provided the starting material.
data.phase_one_digestate_incubations_raw	replicate	float	dimensionless	The experimental-level replicate (e.g., block).
data.phase_one_digestate_incubations_raw	source total solids pct	float	percent	The percent solids of the source material by weight.
data.phase_one_digestate_incubations_raw	source volatile solids ppn	float	NA	The proportion of volatile solids in the source material by weight.
data.phase_one_digestate_incubations_raw	temperature celsius	float	celsius	The incubation temperature.
data.phase_one_digestate_incubations_raw	volume mL	float	milliliter	The volume of the gas listed in product column produced since the last measurement day.
data.phase_two_digestate_incubations_raw	day	integer	number	Days since incubation start.
data.phase_two_digestate_incubations_raw	digestate	string	NA	The residual digestate from phase one that provided the starting material for the phase two serium bottle incubation.
data.phase_two_digestate_incubations_raw	initial substrate g	float	gram	The weight of the initial incubation material, taken from the named reactor during steady-state of phase two.
data.phase_two_digestate_incubations_raw	initial volatile solids g	float	gram	The weight of volatile solids in the initial inubation materials, based on calculations made with the source material.
data.phase_two_digestate_incubations_raw	initial volatile solids pct	float	percent	Volatile solids in the initial material by percent weight.
data.phase_two_digestate_incubations_raw	phase two digestate incubations raw pkey	integer	dimensionless	A unique primary key for this table.
data.phase_two_digestate_incubations_raw	product	string	NA	The gas being measured by volume_mL.
data.phase_two_digestate_incubations_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor that provided the starting material.
data.phase_two_digestate_incubations_raw	replicate	float	dimensionless	The experimental-level replicate (e.g., block). Replicate 1 for 35 degree C did not produce gas, possibly due to a problem with the experimental set-up.
data.phase_two_digestate_incubations_raw	temperature celsius	float	celsius	The incubation temperature.
data.phase_two_digestate_incubations_raw	volume mL	float	milliliter	The volume of the gas listed in product column produced since the last measurement day.
data.recirculated_biogas_methane_proportion_raw	methane proportion mean	float	NA	The mean proportion of the biogas composed of methane produced by the reactor across all measurements.
data.recirculated_biogas_methane_proportion_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.recirculated_biogas_methane_proportion_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.recirculated_biogas_methane_proportion_raw	recirculated biogas methane proportion raw pkey	integer	dimensionless	A unique primary key for this table.
data.recirculated_biogas_methane_proportion_raw	sample 1	float	NA	The proportion of biogas as methane based on volume. Missing values could indicate biogas leakage or bad gas chromatagraph readings from samples out of range. Because the methane concentrations don't vary much over time, we took the average of a number of replicates and used that with average biogas yield to get an average methane yield. The results in these sections are essentially just random samples of the biogas to see how much of it was methane.
data.recirculated_biogas_methane_proportion_raw	sample 2	float	NA	The proportion of biogas as methane based on volume. Missing values could indicate biogas leakage or bad gas chromatagraph readings from samples out of range. Because the methane concentrations don't vary much over time, we took the average of a number of replicates and used that with average biogas yield to get an average methane yield. The results in these sections are essentially just random samples of the biogas to see how much of it was methane.
data.recirculated_biogas_methane_proportion_raw	sample 3	float	NA	The proportion of biogas as methane based on volume. Missing values could indicate biogas leakage or bad gas chromatagraph readings from samples out of range. Because the methane concentrations don't vary much over time, we took the average of a number of replicates and used that with average biogas yield to get an average methane yield. The results in these sections are essentially just random samples of the biogas to see how much of it was methane.
data.recirculated_biogas_methane_proportion_raw	sample 4	float	NA	The proportion of biogas as methane based on volume. Missing values could indicate biogas leakage or bad gas chromatagraph readings from samples out of range. Because the methane concentrations don't vary much over time, we took the average of a number of replicates and used that with average biogas yield to get an average methane yield. The results in these sections are essentially just random samples of the biogas to see how much of it was methane.
data.recirculated_biogas_methane_proportion_raw	sample 5	float	NA	The proportion of biogas as methane based on volume. Missing values could indicate biogas leakage or bad gas chromatagraph readings from samples out of range. Because the methane concentrations don't vary much over time, we took the average of a number of replicates and used that with average biogas yield to get an average methane yield. The results in these sections are essentially just random samples of the biogas to see how much of it was methane.
data.recirculated_biogas_yield_raw	biogas yield ml	float	milliliter	The mean biogas yield over two days divided by two times the calculated daily volatile_solids_fed_g.
data.recirculated_biogas_yield_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.recirculated_biogas_yield_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.recirculated_biogas_yield_raw	recirculated biogas yield raw pkey	integer	dimensionless	A unique primary key for this table.
data.recirculated_biogas_yield_raw	sample 1	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 10	integer	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 11	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 12	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 13	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 14	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 15	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 16	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 17	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 18	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 19	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 2	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 20	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 21	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 22	float	milliliter	The volume of biogas The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and biogas was lost.
data.recirculated_biogas_yield_raw	sample 3	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 4	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 5	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 6	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 7	integer	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 8	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	sample 9	float	milliliter	The volume of biogas produced by the reactor since the previous occasion. Samples were taken every other day. Missing volumes often indicate the collection system leaked and the biogas produced since the last measurement was lost.
data.recirculated_biogas_yield_raw	volatile solids fed g	float	gram	The daily weight of volatile solids fed to the reactor. Reactors were maintained every-other day, so twice this amount was added every other day.
data.recirculated_digestate_liquid_characteristics_raw	ammonia mg per l	float	milligramPerLiter	Ammonia concentration reading from Hach Spectrophotometer. Sample processing done with Hach TNT test kit.
data.recirculated_digestate_liquid_characteristics_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.recirculated_digestate_liquid_characteristics_raw	ph	float	dimensionless	The pH of the liquid fraction of the liquid digestate at this sampling occasion.
data.recirculated_digestate_liquid_characteristics_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.recirculated_digestate_liquid_characteristics_raw	recirculated digestate liquid characteristics raw pkey	integer	dimensionless	A unique primary key for this table.
data.recirculated_digestate_liquid_characteristics_raw	sample	integer	dimensionless	The sample replicate. Reactors were randomly selected on distributed days during the steady state portions of the experimental timeline.
data.recirculated_digestate_liquid_characteristics_raw	test substance	string	NA	The material being tested.
data.recirculated_digestate_liquid_characteristics_raw	total nitrogen mg per l	float	milligramPerLiter	Total nitrogen reading from Hach Spectrophotometer. Sample processing done with Hach TNT test kit.
data.recirculated_digestate_liquid_characteristics_raw	total phosphorus mg per l	float	milligramPerLiter	Total phosphorus reading from Hach Spectrophotometer. Sample processing done with Hach TNT test kit.
data.recirculated_digestate_solids_characteristics_raw	crucible g	float	gram	The weight of the crucible.
data.recirculated_digestate_solids_characteristics_raw	crucible plus ash g	float	gram	The weight of the crucible plus ash after volatilizing in a muffle furnace.
data.recirculated_digestate_solids_characteristics_raw	crucible plus dry g	float	gram	The weight of the crucible plus the digestate after drying at 104 degrees Celcius.
data.recirculated_digestate_solids_characteristics_raw	crucible plus wet g	float	gram	The weight of the crucible plus the wet digestate sample.
data.recirculated_digestate_solids_characteristics_raw	method	string	NA	Indication of whether liquid digestate was recirculated at each feeding. Linear reactors used a fresh slurry of prairie, manure, and water to replace an equal volume of digestate. In recirculated reactors, 50% of the fresh water demand was replaced with liquid digestate filtered from the volume just removed.
data.recirculated_digestate_solids_characteristics_raw	reactor	integer	dimensionless	The designation for the bench-scale reactor used (one liter Erlenmeyer flask).
data.recirculated_digestate_solids_characteristics_raw	recirculated digestate solids characteristics raw pkey	integer	dimensionless	A unique primary key for this table.
data.recirculated_digestate_solids_characteristics_raw	test substance	string	NA	The material being tested.
data.recirculated_digestate_solids_characteristics_raw	total solids percent	float	percent	The percent solids by weight.
data.recirculated_digestate_solids_characteristics_raw	volatile solids percent	float	NA	The proportion of volatile solids by weight.