- General Considerations

             - Specific Considerations

 

 

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Mabie Farm Park - Biomass

According to the methodology, the analysis is divided into 2 parts: Anaerobic Digestion and Biomass Boiler.


Energy from anaerobic digestion process

At Mabie farm, there is no anaerobic digester used to convert their waste and residue into energy. So there is an opportunity to use these available sources for supplying anaerobic digestion technology. These sources can be divided into 3 parts: animal waste, agricultural waste and food waste.

The main purpose of Mabie farm is to serve visitors as a recreation place with lots of activities that families can enjoy together in the summer or at weekends. Therefore, the livestock is only used for show to their visitors, not for selling or supplying food. There are various animals in the farm but the total number of animals is not enough for using their waste as a biomass supply source. This is the same for agricultural waste. The only product from their agriculture is hay, all of which is used as animal food.

The only possibility for Mabie farm is to use food waste from the kitchen and from food that is left by their visitors. However, waste generated by visitors is not constant during the year - it varies with the number of visitors. The estimation of the visitors at Mabie Farm Park and the solid waste generated is shown in table 1:


Table 1. Number of Visitors and Soid Waste Estimation

Month
Visitors
Waste
Waste
Biogas generated
Energy Output 
Energy Output 
(people/wk)
(kg/wk)
(kg/d)
(m3/d)
(kcal)
kWh
Jan
50
25
3.6
0.12
660
0.8
Feb
150
75
10.7
0.36
1980
2.3
Mar
250
125
17.9
0.60
3300
3.8
Apr
500
250
35.7
1.20
6600
7.7
May
1000
500
71.4
2.40
13200
15.4
Jun
2500
1250
178.6
6.00
33000
38.4
July
2500
1250
178.6
6.00
33000
38.4
Aug
2000
1000
142.9
4.80
26400
30.7
Sep
1000
500
71.4
2.40
13200
15.4
Oct
250
125
17.9
0.60
3300
3.8
Nov
50
25
3.6
0.12
660
0.8
Dec
50
25
3.6
0.12
660
0.8

Assumption

Waste Generation Rate 0.5 kg/person/day
Organic Matter Fraction 60%
specific gas production 0.4 m3/kgTVS/d
TS (Total Solid) 20%
VS (Volatile Solid) 70%
Energy from Biogas 5500 kCal/m3


The Estimated energy output varies during the year. This cannot match the energy demand of Mabie farm; therefore it is not practical for using the anaerobic digestion system in this case.

 

  MSc: Renewable Energy Systems and the Environment
© University of Strathclyde 2010