Spreadsheet: 1eb80a2c-6a05-4f4a-8179-88c9fd95cd8f
Sheet: Compost Calculation 

Business name:
Decision maker:
Address:
Determine estimated compost mix and composting time
Given:
Step1a:
Bulking Agent:
Pen Size: |  | 'W           x |  | 'L                           = |  | ft2
amount: |  | in thick x (1ft÷12in) x |  | ft2 x (1yd3÷27ft3) = |  | yd3
 |  | yd3 x (27ft3÷1yd3) x | 0 | lb/ft3                      = |  | lbs/pen per day
 |  | yd3          x | 0 | lb/yd3                     = |  | lbs/pen per day
Note: 12 inches in 1 foot, 27 ft3 in 1 yd3, and __lb/ft3 or _lb/yd3 for bulking agent
See Ref. [NAME] for bulking agent information
Mwa% = moisture content: |  |  | %
% N = |  | % | C:N Ratio = |  | :1
See Ref. Tables for bulking agent information
Manure:
Animal Units (AU) = |  |  | AU
Mm% = percent moisture: |  |  | %
manure production: |  |  | lbs/day/AU
nitrogen production: |  |  | lbs/day/AU | See note on Instructions Tab for Nitrogen reductions that may occur because of volatilization.
 | fixed solids: |  | lbs/day/AU
volatile solids: |  |  | lbs/day/AU
confined in building per day: |  |  | day
 | pens per building: |  | pens/building
 | hrs/day confined: |  | hrs/day
As excreted values computed separately.  Use USDA NRCS National Engineering Handbook part 651, Ag Waste Management Field Handbook, ASAE Standard D384.1 Dec 93 Manure Production and Characteristics, or actual measurements and analysis (use representative sampling in sufficient numbers to justify extrapolating values, particularly if results are significantly different than book values).  ASAE 1993 data includes standard deviation, useful for giving a range for evaluating reasonableness of site specific measurements.
Step 1b: [NAME] Agent
See bulking agent data above
Step 2a: Determine the moisture content of the waste
Wwa = wet weight of bulking agent in barn:
amount: |  | in thick = |  | cu.yds = |  | lbs/pen per day
 |  | x pen per bld. |  | pens per bld. |  | lbs/building per day
Wm = wet weight of manure in building:
Total AU *manure production*confined in building = |  |  |  |  | lbs per day
Wmwa = wet weight of manure plus bulking agent
Wmwa = Wwa + Wm = |  |  | lbs per day
determine moisture content of manure plus bulking agent:
See Equation [10-11] p.10-49
[NAME] = (((Wm*Mm%)+(Wwa*Mwa%))÷100))÷(Wmwa) = |  |  |  |  | %
where:
[NAME] = % moisture of manure plus bulking agent
Wm = wet weight of manure
Mm% = % moisture content of manure
Wwa = wet weight of bulking agent
Mwa% = % moisture content of bulking agent
Wmwa = weight of manure plus bulking agent
Step 2b: Determine amount of additional bulking agent to added, if any, to the compost mix
that will result in desired final moisture content that is between 40% to 60%
See Equation [10-12] p.10-50
Waa= ((Wmwa)*(Mmwa-Md))÷(Md-Maa) = |  |  |  | lbs
where:
Waa= Wet weight of additional bulking agent to be added
Wmwa=wet weight of manure plus bulking agent
Mmwa= % moisture content of manure plus bulking agent
[NAME] desired % moisture of compost mixture (between 40% to 60%)
Maa = %moisture content of additional bulking agent
Wmwa= |  | lbs per day
Mmwa= |  | %
Maa= |  | %                         Md= |  | %
Wwa = Wwa + Waa = |  | lbs
For Wmwa & Mmwa input data from calculated data
For Maa & Md adjust as needed
until desired moisture content (between 40% to 60%) is reached
Since compost mix is within the desired moisture content
no amendment is needed.
Step 3: Calculate the C:N Ratio of compost mix
Determine the carbon and nitrogen content of the bulking agent:
Wwa = total weight of bulking agent: |  |  |  | lbs per day
 | Wdrywa = Wwa*((100-Mw%)÷100) = |  |  | lbs per day
where:
Wwa= wet weight of bulking agent
Mwa% = % moisture content of bulking agent
Wdrywa = dry weight of bulking agent
Note: See Equation [10-18] p.10-50
weight of nitrogen in bulking agent:
Wnwa = ((%N*Wdrywa)÷100) = |  |  |  | lbs per day
Note: See Equation [10-16a] p.10-50
Wcwa = weight of carbon in bulking agent:
Wcwa = Wnwa * C:N = |  |  | lbs per day
Note: See Equation [10-17b] p.10-50
Determine the carbon and nitrogen content in manure:
volume of volatile solids in piggery building:
VS = total AU*volatile solids /day*confined in barn = |  |  |  |  | lbs per day
weight of carbon in manure:
Wcm = VS÷1.8 = |  |  | lbs per day
Note: See Equation [10-13b] p.10-50
weight of nitrogen in manure:
Wnm = AU * nitrogen production * time swine in piggery building per day
Wnm = |  | lbs per day
C:N Ratio of manure: |  | Wcm/Wnm =
Determine C:N ratio of manure and bulking agent mixture:
C:N = (Wcm+Wcwa)÷(Wnm+Wnwa) =
Note: See Equation [10-15] p.10-50
If manure and bulking agent mixture C:N Ratio
is at the desired C:N Ratio 25:1 to 40:1
no amendment needed to achieve C:N Ratio
Step 3b - Determine the amount of commercial nitrogen |  |  |  | See note on the instructions sheet regarding alternatives to adding commercial nitrogen, [NAME] [NAME] 14
to add to bring the C:N ratio to 25:1 to 40:1
weight of nitrogen in current compost mix:
Wcompost = Wnm+Wnwa = |  |  | lbs per day
Wdrym = Wm*((100-Mm%)÷100) = |  |  |  | lbs per day
where:
Wm = wet weight of manure
Mm% = % moisture content of manure
Wdrym = dry weight of manure
Note: See Equation [10-18] p.10-50
% N in manure = (Wnm÷Wdrym)*100 = |  |  |  | %
Pounds of commercial nitrogen to add to bring compost mix to 25:1 to 40:1:
Wnd = ((Wcm+Wcwa)÷Rd)-(Wnm+Wnwa) = |  |  |  | lbs per day
where:
Wnd = dry weight of commercial nitrogen to add to mix
Wcm = weight of carbon in manure
Wcwa = weight of carbon in bulking agent
Wnm = weight of nitrogen in manure
Wnwa = weight of nitrogen in bulking agent
Rd = desired C:N ratio of 25 to 40
Note: See Equation [10-21] p.10-51
The final compost mix consists of the following:
Manure and bulking agent moved out of piggery by animals
and gravity in dry litter waste management system: |  |  |  |  | lbs per day
Nitrogen added to lower C:N Ratio: |  |  |  |  | lbs per day
windrow or static pile method ~ 14 day to a month time needed to compost
in vessel method ~ 7 days time needed to compost
(optional) curing compost ~ 30 to 90 days
For Equations, See Reference
Agricultural Waste Management Field Handbook
p.10-49 to 10-58 March 2012
 | Input Data
 | Calculated Data
 | Answer