RUFAS.biophysical.manure.manure_constants module

class RUFAS.biophysical.manure.manure_constants.ManureConstants

Bases: object

A class to store constants for manure management.

LIQUID_MANURE_DENSITY = 1000

The density of liquid manure (kg/\(m^3\)).

SLURRY_MANURE_DENSITY = 990

The density of slurry manure (kg/\(m^3\)).

SOLID_MANURE_DENSITY = 700

The density of solid manure (kg/\(m^3\)).

ACHIEVABLE_METHANE_EMISSION = 0.24

Achievable emission of methane from dairy manure (m^3 methane / kg volatile solids).

HOUSING_SPECIFIC_CONSTANT = 260.0

Default housing specific constant (s/m) used in the calculation of ammonia emissions from manure deposited in

freestall or tiestall barns. Default is set to 260.0 s/m.

DEFAULT_PH_FOR_HOUSING_AMMONIA: float = 7.7

Default pH for manure on tiestall or freestall barn floors (unitless). Default is set to 7.7.

MILKING_FRESH_WATER_USE_RATE: float = 30.0

The milking fresh water use rate for each animal (L/animal/day).

METHANE_MOLAR_MASS = 16.04

Molar mass of methane (g).

CARBON_DIOXIDE_MOLAR_MASS = 44.01

Molar mass of carbon dioxide (g).

CARBON_DIOXIDE_TO_METHANE_RATIO: float = 0.6666666666666666

Volumetric ratio of carbon dioxide to methane generated during anaerobic digestion (m^3 carbon dioxide / m^3 methane).

TAN_INCREASE_FACTOR = 1.6

Factor by which total ammoniacal nitrogen content is increased by the anaerobic digestion process (unitless).

METHANE_TO_METHANE_CARBON_DIOXIDE_RATIO: float = 9.25

The mass conversion factor from methane to methane and carbon dioxide emitted from stored manure, based on a molar ratio of 1:3 (methane : carbon dioxide).

METHANE_DESTRUCTION_EFFICIENCY = 81

The percentage of methane destroyed in systems using a cap and flare

STORAGE_RESISTANCE = 4.1

Resistance value utilized in calculation of ammonia emission from manure stored in slurry storage outdoor, slurry storage underfloor, or anaerobic lagoon (s/m).

STORAGE_COVER_NITROUS_OXIDE_EMISSIONS_FACTOR_MAPPING: dict[StorageCover, float] = {StorageCover.COVER: 0.005, StorageCover.COVER_AND_FLARE: 0.005, StorageCover.CRUST: 0.005, StorageCover.NO_COVER: 0.0}

Mapping of storage cover types to the nitrous oxide emissions factor associated with that cover type (kg nitrous oxide N / kg manure N).

DEFAULT_STORED_MANURE_PH: float = 7.5

Default pH of manure in slurry storage or anaerobic lagoon (unitless).

ACTIVATION_ENERGY: float = 81000.0

Apparent activation energy of methanogenesis in dairy manure (joules per mole, J/mol). The activation energy is the

minimum energy that must be available to microbes for methanogenesis to occur.

NATURAL_LOG_ARRHENIUS_CONSTANT: float = 31.2

Natural log of the Arrhenius parameter used in determination of methane emissions from stored slurry or liquid manure (g methane / kg manure Volatile Solids / hour).

DEFAULT_LAG_TIME = 2

Default lag time used in the calculation of the carbon decomposition rate (days). Default is set to 2.

LEACHING_COEFFICIENT: float = 0.035

Leaching coefficient used in the calculation of leaching N loss in a compost bedded pack and open lot (unitless).

DEFAULT_LAYER_TEMPERATURE: float = 30

The default layer temperature for open lot and compost bedded pack barn.

NITROUS_OXIDE_COEFFICIENT_WITH_TILLED_BEDDING: float = 0.07

Nitrous oxide coefficient used for calculating nitrogen loss in a compost bedded pack barn when the bedding is tilled (unitless).

NITROUS_OXIDE_COEFFICIENT_WITH_UNTILLED_BEDDING: float = 0.01

Nitrous oxide coefficient used for calculating nitrogen loss in a compost bedded pack barn when the bedding is not tilled (unitless).

AMMONIA_EMISSION_COEFFICIENT_WITH_TILLED_BEDDING: float = 0.5

Ammonia emission coefficient used for calculating nitrogen loss in a compost bedded pack barn when the bedding is tilled (unitless).

AMMONIA_EMISSION_COEFFICIENT_WITH_UNTILLED_BEDDING: float = 0.25

Ammonia emission coefficient used for calculating nitrogen loss in a compost bedded pack barn when the bedding is not tilled (unitless).

MCF_COMPOSTING_STATIC_PILE: float = 0.005

The MCF for static pile composting.

MCF_LOWER_BOUND_TEMPERATURE: float = 15.0

The lower bound temperature for determining MCF for windrow composting.

MCF_UPPER_BOUND_TEMPERATURE: float = 25.0

The upper bound temperature for determining MCF for windrow composting.

MCF_COMPOSTING_WINDROW_LOW: float = 0.005

The MCF for windrow composting when the air temperature is below the lower bound temperature.

MCF_COMPOSTING_WINDROW_MEDIUM: float = 0.01

The MCF for windrow composting when the air temperature is between the lower and upper bound temperature.

MCF_COMPOSTING_WINDROW_HIGH: float = 0.015

The MCF for windrow composting when the air temperature is above the upper bound temperature.

AMMONIA_EMISSION_COEFFICIENT_IN_OPEN_LOTS: float = 0.36

Ammonia emission coefficient used for calculating nitrogen loss in an open lot (unitless).

NITROUS_OXIDE_COEFFICIENT_IN_OPEN_LOTS: float = 0.02

Nitrous oxide coefficient used for calculating nitrogen loss in an open lot (unitless).

DEFAULT_CARBON_FRACTION_AVAILABLE_IN_VSD: float = 0.5

Default carbon content (percent by mass) of manure degradable volatile solids (unitless, [0, 1]).

DEFAULT_CARBON_FRACTION_AVAILABLE_IN_VSND: float = 0.35

Default carbon content (percent by mass) of manure non-degradable volatile solids (unitless, [0, 1]).

DEFAULT_EFFECT_OF_MOISTURE_ON_MICROBIAL_DECOMPOSITION: float = 0.65

The default effect of moisture on microbial decomposition.

DEFAULT_DAYS_SINCE_LAST_MIXING: int = 1

Default days since the previous mixing event (days). Default is set to 1. For Composting, this refers to compost turning. For Open Lot, this refers to lot harrowing. For Compost Bedded Pack barn, this refers to pack tillage.

DEGRADABLE_VOLATILE_SOLIDS_RATE_CORRECTING_FACTOR: float = 1.0

Rate correcting factor for degradable volatile solids, used in calculation of slurry storage methane emission (unitless).

NON_DEGRADABLE_VOLATILE_SOLIDS_RATE_CORRECTING_FACTOR: float = 0.01

Rate correcting factor for non-degradable volatile solids, used in calculation of slurry storage methane emission (unitless).

EFFECTIVENESS_OF_MICROBIAL_DECOMPOSITION_RATE: float = 0.00237

The rate of effectiveness of microbial decomposition.

FIRST_ORDER_DECAYING_COEFFICIENT: float = 0.1

The first order decaying coefficient.

DECOMPOSITION_TEMPERATURE: float = 60.0

The temperature of the inner decomposing material layer at which microbial growth and decomposition is maximized (C).

OXYGEN_HALF_SATURATION_CONSTANT: float = 0.02

The half saturation constant of Oxygen gas (O2)

MCF_CONSTANT_A: float = 0.0625

Parameter estimate (unitless) of a regression using IPCC data (2006) used in the open lot Methane Conversion Factor (MCF) calculation. The coefficient scales the ambient barn temperature.

MCF_CONSTANT_B: float = 0.25

Parameter estimate (unitless) of a regression using IPCC data (2006) used in the open lot Methane Conversion Factor (MCF) calculation. The coefficient is a constant offset.

DEFAULT_MOLE_FRACTION_OF_OXYGEN: float = 0.15

The default mole fraction of oxygen in the air within the decomposing material layer.