Economic Effects of Sustainable Sanitation - SuSanA

Case Study Kampala
incentive for each container. Upfront investments that have to be financed in addition to the
investments made for the urine system (system A) were:
Faeces-boxes for exchange at the collection points
Trucks
Drying bed
The investments have been calculated with an interest rate of 6.6% and the investment costs
for the toilet facilities have not been included in the calculations. The hidden cost‘s
contribution to the total costs was in system B just as in system A included with 5%.
The scenarios in Table 6 were calculated based on the same N demands as used in Table 5 for
system A. Hence the volume of urine and the number of people producing it are not changing.
The amount of faeces generated by the individual numbers of people is 92 909, 139 983 and
902 999 kg/month for the scenarios small scale I, small scale II and large scale, respectively.
The workload indicator for the urine share of the system remains the same as in Table 5. The
workload indicator for the faeces share makes a difference, though. It rises from 0.310 for the
small scale I scenario, over 0.467 up to 0.752 for the small scale II and large scale scenario.
However, the mechanisms behind this monotonous increase are the same as in the urine
system.
The income from selling the urine fertiliser is the same as in system A. The income from
selling the dried faeces fertiliser bags is 2 860, 4 309 and 27 794 EUR, leading to 7 127,
10,738 and 69 267 EUR total income for the small scale I, - small scale II and - large scale
scenario, respectively. The monthly costs of the same scenarios add up to 8 587, 10 076 and
56 917 EUR, resulting in a monthly balance of -1 460, 662 and 12 349 EUR. The small scale
I scenario again had to be neglected due to a negative balance.
The monthly return on sales is hence calculated as being 6.16% for the small scale II and
17.83% for the large scale scenario. Compared to system A the return on sales is smaller
(10.87% for the small scale II and 21.7% for the large scale scenario of system A).
Also the investments for system B show differences in relation to system A. Firstly, with
160.022, 163 376 and 843 427 EUR for the three scenarios, the values of system A are higher
than for system B. This is influenced by additional investments for the infrastructure for
faeces management. Secondly, unlike in system A, the values of the two small scale scenarios
are different from each other. The trigger for that is located in the investments for the faeces-
boxes that are handed out in exchange. The repayment periods are 20.58 and 5.69 years for
the small scale II and the large scale scenario, respectively. The results of this cost
calculation also show that the bigger the N demand of the consumers and hence the bigger the
system is dimensioned, the higher is the return on sales and subsequently the shorter is the
repayment period. Since resulting in a negative balance the return on sales and the repayment
period for the small scale I scenario could not be calculated.
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