Calculate Biogas Production from Gas Density Data (GD-BMP)
calcBgGD (for calculate biogas from GD (gas density) measurements) calculates cumulative biogas, methane production and production rates from mass loss and volume measurements for any number of bottles.
calcBgGD( # Main arguments dat, temp.vol, temp.grav, pres.vol, pres.grav, # Column names id.name, time.name, vol.name, m.pre.name = NULL, m.post.name, comp.name = 'xCH4', # Settings vented.mass = FALSE, averaging = 'final', temp.init = NULL, pres.init = NULL, headspace = NULL, vol.hs.name = NULL, headcomp = 'N2', # Calculation method and other settings vmethod = 'vol', comp.lim = c(0, 1), comp.sub = NA, imethod = 'linear', extrap = FALSE, addt0 = TRUE, showt0 = TRUE, dry = FALSE, # Warnings and messages std.message = TRUE, check = TRUE, # Units and standard conditions temp.std = getOption('temp.std', as.numeric(NA)), pres.std = getOption('pres.std', as.numeric(NA)), unit.temp = getOption('unit.temp', 'C'), unit.pres = getOption('unit.pres', 'atm') )
dat: a data frame with bottle identification code, time of measurement (as numeric, or POSIX), bottle mass, and measured biogas volume. See Details section for details on units. Additional columns can be present--these will be returned in the output data frame.temp.vol: temperature at which biogas volume was measured.temp.grav: temperature of bottle headspace at time of biogas venting, prior to gravimetric measurement.pres.vol: pressure at which biogas volume was measured.pres.grav: pressure of bottle headspace at time of biogas venting, prior to gravimetric measurement.id.name: name of the bottle identification code column in dat. Must be the same in all data frames used in the function.time.name: name of column containing time data (cumulative time) in dat.vol.name: name of the measured biogas volume column in dat.m.pre.name: name of column containing pre-venting bottle mass in dat data frame. Optional, required for vented.mass = TRUE and to calculate leakage.m.post.name: name of column containing post-venting bottle mass in dat data frame. See details.comp.name: name of column with biogas composition to be added to output data frame.vented.mass: Set to TRUE to use vented mass loss (GD_v method) instead of total mass loss (GD_t method) in calculations. See details.averaging: type of averaging used for calculating biogas composition. Default is final. See details.temp.init: optional initial headspace temperature. Used to correct results for initial headspace. See details.pres.init: optional initial headspace pressure. Used to correct results for initial headspace. See details.headspace: optional data frame or length-one numeric vector with reactor headspace volume(s). If a data frame is used, it should at least contain a "id" (reactor identification code) column (see "id.name") and headspace volume column (see vol.hs.name argument). Required if cmethod = "total". Default is NULL.vol.hs.name: optional name of column containing headspace volume data in optional headspace data frame.headcomp: optional initial headspace composition used to correct results for initial headspace. Default of "N2" is only logical value.vmethod: method used for calculating biogas volume. Default of 'vol' is based on measured biogas volume in vol.name column. Alternative is 'grav' for gravimetric method, which should be used with vented.mass = TRUE.comp.lim: acceptable limits on calculated methane mole fraction. Any values outside of this range are set to comp.sub. Default of c(0, 1). Length two vector.comp.sub: Value substituted in for calculated methane mole fraction when calculated value is outside of comp.lim range. Length one vector. Default value of NA should generally never be changed.imethod: method used for interpolation of xCH4. This is passed as the method argument to interp. Length one character vector. Default is "linear" for linear interpolation.extrap: should comp.name be extrapolated? Length one logical vector. This is passed as the extrap argument to interp. Default is FALSE.addt0: is the earliest time in dat data frame time zero (start time)? If not, this argument adds a row with time.name = 0 for each reactor in order to calculate production rates for the first observation. This addition is only made when time.name is numeric (or integer). Length-one logical vector. Default is TRUE. To return these additional rows in the output, see showt0.showt0: should time zero rows be returned in the output? Can be convenient for plotting cumulative volumes. Only applies if time.name is numeric (or integer). These rows may have been present in the original data (dat) or added by the function (see addt0). Default value depends on dat time.name column content. If time.name column is numeric and contains 0 then the default value is TRUE and otherwise FALSE.dry: set to TRUE if volume data are standardized to dry conditions. The default (FALSE) means biogas is assumed to be saturated with water vapor.std.message: should a message with the standard conditions be displayed? Default is TRUE.check: should input data be checked for unreasonable values (with warnings)? Currently only composition values are checked. Default is TRUE. Values are changed if outside 0, 1 (divided by 100).temp.std: standard temperature for presentation of biogas and methane results. Length one numeric vector. Default value is 0 degrees C (set in stdVol). Argument is passed to stdVol.pres.std: standard pressure for presentation of biogas and methane results. Length one numeric vector. Default value is 1.0 atm (101325 Pa) (set in stdVol). Argument is passed to stdVol.unit.temp: temperature units for temp and temp.std arguments. Default is "C" for degrees Celcius. Argument is passed to stdVol.unit.pres: pressure units for pres and pres.std arguments. Default is "atm". Argument is passed to stdVol.Using volume and mass loss data from dat, this function will calculate standardized biogas and methane production for each observation using the gas density (GD) method. See reference below for details on the method.
Standard values and units for temperature and pressure can be globally set using the function options. See stdVol.
a data frame with all the columns originally present in dat, plus others including these: - vBg: Standardized volume of biogas production for individual event.
xCH4: Calculated mole fraction of methane in biogas.
vCH4: Standardized volume of methane production for individual event.
cvBg: Standardized cumulative volume of biogas production.
cvCH4: Standardized cumulative volume of methane production.
rvBg: Production rate of biogas.
rvCH4: Production rate of methane.
Units are based on units in input data.
Justesen, C.G., Astals, S., Mortensen, J.R., Thorsen, R., Koch, K., Weinrich, S., Triolo, J.M., Hafner, S.D. 2019. Development and validation of a low-cost gas density method for measuring biochemical potential (BMP) Water (MDPI) 11(12) : 2431.
Sasha D. Hafner, Camilla Justesen, Jacob Mortensen
calcBgMan, calcBgVol, summBg, interp, stdVol, options
data("UQGDBiogas") data("UQGDSetup") head(UQGDBiogas) head(UQGDSetup) cbg <- calcBgGD(UQGDBiogas, temp.vol = 20, pres.vol = 1013.25, temp.grav = 30, pres.grav = 1500, id.name = 'id', vol.name = 'vol', m.pre.name = 'mass.init', m.post.name = 'mass.final', time.name = 'time.d', unit.pres = 'mbar') BMP <- summBg(cbg, UQGDSetup, id.name = "id", time.name = 'time.d', descrip.name = 'descrip', inoc.name = "Inoculum", inoc.m.name = "m.inoc", norm.name = "m.sub.vs", when = 'end') BMP
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