## 3 Results
### Comparison between Water Supply Alternatives for the CMPs  
Based on the estimated total monthly demand of 6110 m\({}^{3}\), a volume of 73,320 m\({}^{3}\) of reclaimed water was considered to be consumed by the four CMPs, each year.  
Based on the estimated consumption range and location of the CMPs, the local water company (CEDAE) tariff of BRL 35.76 (USD 7.38) per m\({}^{3}\) was adopted (Alternative A),  
Figure 4: Diagram of the projected distribution system to supply the four CMPs with reclaimed water from the Alegria WRP/WTP.  
while the cost of potable water transported by water tank trucks adopted was BRL 33.25 (USD 6.76) per m\({}^{3}\) (Alternative B), based on average cost of five market quotations made by companies providing these sorts of services in MRRJ.  
On the other hand, for both alternatives which employ reclaimed water (Alternatives C and D), the cost adopted was BRL 7.85 (USD 1.60) per m\({}^{3}\), disregarding transportation. The transportation cost per tank truck determined was BRL 24.92 (USD 5.07) per m\({}^{3}\), resulting in a total of BRL 32.77 (USD 6.66) per m\({}^{3}\) for Alternative C.  
The estimated initial investment for the implementation obtained with the reclaimed water supply system using a pipeline was BRL 309,327.00 (USD 62,871.35). In the first year, the system operation cost was BRL 5760.40 (USD 1170.81), or BRL 0.016 (USD 0.003) per m\({}^{3}\). Thus, the total estimated operational cost was BRL 5.79 (USD 1.18) per m\({}^{3}\) for Alternative D.  
Figure 5 presents the differences (savings) between the cash flows for the three alternatives (A, B, and C) compared to Alternative D (reclaimed water supply using a pipeline), discounted for a COC of 10.81%, with the 10-year project horizon adopted.  
Based on the comparison between the cash flows, the savings provided increase over the years and the most significant difference corresponds to the comparison between Alternatives A (potable water from the conventional distribution pipeline network) and D (reclaimed water from the Alegria WRP/WTP using a pipeline network).  
Overall, Alternative D--referring to a distribution system (pipeline) using reclaimed water--showed the highest financial feasibility, with the lowest average projected cost of BRL 4.85 (USD 0.99) per m\({}^{3}\), while the supply cost of reclaimed water using water tank trucks was estimated at BRL 32.77 (USD 6.66) per m\({}^{3}\). Regarding the use of potable water, as already mentioned, the costs are BRL 35.76 (USD 7.38) per m\({}^{3}\) and BRL 33.25 (USD 6.76) per m\({}^{3}\), using the conventional water distribution network and water tank trucks, respectively.  
According to the results obtained, the investments made for Alternative D implementation were already amortized in the first year after the start of operation of the reclaimed water distribution system using a pipeline network. The sensitivity analysis using the ranges found presented the same conclusions and showed that this project would still be feasible under uncertainty.  
Figure 5: Difference between the discounted cash flows of water supply Alternatives A, B, and C and Alternative D.  
Actually, the information gathered by this study has demonstrated that there are two distinct levels of water supply costs for the evaluated cluster of four CMPs: a higher level, corresponding to the alternatives using potable water, either through transportation by the conventional network distribution system or water tank trucks, and a lower level, corresponding to the supply alternatives using reclaimed water, either through a pipeline or water tank trucks. The considerable difference that can be observed between these two levels of costs provides greater certainty in relation to the research results obtained, demonstrating the potential and feasibility of using reclaimed water to supply the cluster of the listed CMPs in the Caju neighborhood.