of waste used to produce the final product and
the land size of the compost plants. The amount
of waste processed varied between less than 100
ton/year in the smallest plants up to more than
1,000 ton/year in large plants. In this study, the
plants were categorized into three groups based
on their production capacity as small (<100
tons), medium (100–500 tons) and large (>500
tons) scale. The dominant feedstocks used for
compost production are household and market
waste with agro waste including animal dung as
additional feedstocks. The majority of the compost plants have an annual production capacity
ranging between 100 and 500 tons with only a
few of them having an annual production
capacity of either less than 100 ton or greater
than 500 tons. The annual average quantity of
waste processed is 139 tons in the smallest case
and more than 1,000 tons in the largest case. The
average input–output conversion rate for the
small scale plants is 0.55 ton/ton of input processed while for the larger plants, it is 0.50
ton/ton of input. The plants operate at an average
capacity utilization of 52% with the larger plants
operating at an average capacity utilization of
75% indicating that the plants are not operating
at full capacity. The average land size for the
plants is 0.70 acres in the smallest case while in
the larger cases, the average land size is 1.74
acres indicating that land size increases as the
plant capacity increases. The majority of the
plants use open windrow composting method in
their production process, which requires more
land as production capacity increases.
Investment costs are a total of the whole
installation inclusive of land, building, machine,
equipment and other costs. The average investment cost per unit of capacity in the smallest
plants is 15,433 KES/ton (153 USD/ton) while in
the largest cases, it is 12,583 KES/ton (125
USD/ton). It can be observed that as the capacity
of the plant increases, the average investment
cost per unit of capacity decreases. Moreover,
investment cost per unit of capacity showed
variation among different plants within their
respective scales as manifested in the large
standard deviations. Mean investment cost,
looking at all the plants is 14,523 KES/ton (144
USD/ton). Production and operational cost,
which comprises raw material, labor, utilities,
administration and marketing cost, is 4,833
KES/ton (48 USD/ton) in the smallest plants and
3,908 (39 USD/ton) in the medium sized.
Looking at all the plants, the mean production
cost is 3,831 KES/ton (38 USD/ton). The
depreciation rate for the small plants is 3% while
for the largest plants it is at 7%. The operational
and maintenance costs for small plants are 1.2%
and for the larger plants, it is 3% of the total
investment cost excluding land. The average
price of compost varies among the plants within
their respective ranges. The average price of the
compost is 14,000 KES/ton (139 USD/ton) in the
case of medium sized plants. The corresponding
figures for the small and large plants are 20,000
(198.5 USD/ton) and 22,500 KES/ton (223
USD/ton), respectively. The average price of the
compost for all the plants is 19,210 KES/ton (191
USD/ton). The variation in the price of compost
among the different scales of compost plants
could be due to different factors such as variation
in the way the compost is distributed to the final
buyer, variation in the marketing strategies of
different plants and variation in the quality and
cost of production of the compost product.
The cost of land accounts for 38% and 35% of
the total investment cost for the smallest and
largest compost plants respectively, whilst it
accounts for about 51% of the investment cost
for the medium sized plants (Fig. 3). Land
accounts for 45% of the total investment cost for
all the compost plants and it is a major cost for
the plants. The majority of the plants use low
technology processes, which require more space
to sort and process raw materials using manual
labor and low cost machinery. In addition to
land, plant infrastructure is a major cost for large
scale plants accounting for more than one-third
of the total investment cost. Machines and
equipment account for about one-third of the
total investment cost of all surveyed plants.
The production and operational cost components include raw material, labor, utilities, marketing and administration costs (Fig. 4). Labor
cost stands out as the major cost for all the
surveyed plants, which is expected as most of the
30
S. Gebrezgabher et al.
the land size of the compost plants. The amount
of waste processed varied between less than 100
ton/year in the smallest plants up to more than
1,000 ton/year in large plants. In this study, the
plants were categorized into three groups based
on their production capacity as small (<100
tons), medium (100–500 tons) and large (>500
tons) scale. The dominant feedstocks used for
compost production are household and market
waste with agro waste including animal dung as
additional feedstocks. The majority of the compost plants have an annual production capacity
ranging between 100 and 500 tons with only a
few of them having an annual production
capacity of either less than 100 ton or greater
than 500 tons. The annual average quantity of
waste processed is 139 tons in the smallest case
and more than 1,000 tons in the largest case. The
average input–output conversion rate for the
small scale plants is 0.55 ton/ton of input processed while for the larger plants, it is 0.50
ton/ton of input. The plants operate at an average
capacity utilization of 52% with the larger plants
operating at an average capacity utilization of
75% indicating that the plants are not operating
at full capacity. The average land size for the
plants is 0.70 acres in the smallest case while in
the larger cases, the average land size is 1.74
acres indicating that land size increases as the
plant capacity increases. The majority of the
plants use open windrow composting method in
their production process, which requires more
land as production capacity increases.
Investment costs are a total of the whole
installation inclusive of land, building, machine,
equipment and other costs. The average investment cost per unit of capacity in the smallest
plants is 15,433 KES/ton (153 USD/ton) while in
the largest cases, it is 12,583 KES/ton (125
USD/ton). It can be observed that as the capacity
of the plant increases, the average investment
cost per unit of capacity decreases. Moreover,
investment cost per unit of capacity showed
variation among different plants within their
respective scales as manifested in the large
standard deviations. Mean investment cost,
looking at all the plants is 14,523 KES/ton (144
USD/ton). Production and operational cost,
which comprises raw material, labor, utilities,
administration and marketing cost, is 4,833
KES/ton (48 USD/ton) in the smallest plants and
3,908 (39 USD/ton) in the medium sized.
Looking at all the plants, the mean production
cost is 3,831 KES/ton (38 USD/ton). The
depreciation rate for the small plants is 3% while
for the largest plants it is at 7%. The operational
and maintenance costs for small plants are 1.2%
and for the larger plants, it is 3% of the total
investment cost excluding land. The average
price of compost varies among the plants within
their respective ranges. The average price of the
compost is 14,000 KES/ton (139 USD/ton) in the
case of medium sized plants. The corresponding
figures for the small and large plants are 20,000
(198.5 USD/ton) and 22,500 KES/ton (223
USD/ton), respectively. The average price of the
compost for all the plants is 19,210 KES/ton (191
USD/ton). The variation in the price of compost
among the different scales of compost plants
could be due to different factors such as variation
in the way the compost is distributed to the final
buyer, variation in the marketing strategies of
different plants and variation in the quality and
cost of production of the compost product.
The cost of land accounts for 38% and 35% of
the total investment cost for the smallest and
largest compost plants respectively, whilst it
accounts for about 51% of the investment cost
for the medium sized plants (Fig. 3). Land
accounts for 45% of the total investment cost for
all the compost plants and it is a major cost for
the plants. The majority of the plants use low
technology processes, which require more space
to sort and process raw materials using manual
labor and low cost machinery. In addition to
land, plant infrastructure is a major cost for large
scale plants accounting for more than one-third
of the total investment cost. Machines and
equipment account for about one-third of the
total investment cost of all surveyed plants.
The production and operational cost components include raw material, labor, utilities, marketing and administration costs (Fig. 4). Labor
cost stands out as the major cost for all the
surveyed plants, which is expected as most of the
30
S. Gebrezgabher et al.