However, such changes in the proportions of the pump construction and operation cost were not observed in the Apulian-52.5 network (Table 4). Because the tank water level changes are not rapid, the highest robustness level (9 m) in the Apulian-52.5 network was bigger than that (6.6 m) in the Apulian-35 network. To compensate for the bigger tank size, a bigger pump was constructed for the Apulian-52.5 network than for the Apulian-35 network (e.g., two 90 kW pumps in the least-cost solution of the former and two 75 kW pumps in that of the latter). To have the same level of robustness, fewer total costs were invested in the Apulian-52.5 network than in the Apulian-35 network (e.g., 6.5 million USD for SRobreq = 9 m in the former, while 6.9 million USD for the same SRobreq of the latter) (Tables 3 and 4). The improved resourcefulness from the increased tank capacity helped improve the cost-effectiveness of the robustness-based operation.
Austin network's pump design and scheduling solutions obtained with a bigger tank capacity (tank volume = 12,755 tons)
Daily maximum pressure difference (m) . | Pump capacity (kW) . | Number of pumps . | POC (%) . | PCC (%) . | Total cost (USD) . |
---|---|---|---|---|---|
26.9 | 90 | 2 | 3,593,519 (66) | 1,889,698 (34) | 5,483,217 |
15.0 | 75 | 2 | 3,923,947 (69) | 1,756,790 (31) | 5,680,737 |
10.0 | 55 | 3 | 4,006,493 (66) | 2,061,125 (34) | 6,067,618 |
9.0 | 55 | 3 | 4,416,814 (68) | 2,061,125 (32) | 6,477,939 |
Daily maximum pressure difference (m) . | Pump capacity (kW) . | Number of pumps . | POC (%) . | PCC (%) . | Total cost (USD) . |
---|---|---|---|---|---|
26.9 | 90 | 2 | 3,593,519 (66) | 1,889,698 (34) | 5,483,217 |
15.0 | 75 | 2 | 3,923,947 (69) | 1,756,790 (31) | 5,680,737 |
10.0 | 55 | 3 | 4,006,493 (66) | 2,061,125 (34) | 6,067,618 |
9.0 | 55 | 3 | 4,416,814 (68) | 2,061,125 (32) | 6,477,939 |