A municipality of 500,000 people is presently relying solely on an external landfill to satisfy waste disposal needs. The elected officials wish to develop an integrated waste management system, which will potentially require the development of a centralized composting facility, a materials recycling facility, and an incineration (waste-to-energy) facility. The materials not handled by these facilities will be routed to an external landfill along with residue from the waste-to-energy facility (external landfill is assumed to have no capacity constraints).

Based on the given information, develop an approach to determine which facilities should be developed, when they should be developed, and at what capacity (assume that a facility will either not be developed, or developed at some capacity level that will stay constant for the remainder of the planning horizon, i.e., expansions of facilities are not be considered). The overall planning horizon is 15 years, broken into three equal periods of 5 years each. The municipality is assuming at-source waste reduction initiatives to occur over time, such that wastes requiring management at the 5-year point will be 90% of the year zero level, and at the 10-year point will be 80% of the year zero level (i.e., the wastes requiring composting/recycling/incineration/landfilling will be reduced over time). Assume all facilities to operate 365 days/year, and per capita waste generation at year zero to be 1.0kg/person/day. Capital expenditures on waste management facilities are limited by budget restrictions to $20 million (year zero $) in any period.

Composting

- 25% of generated wastes are potentially compostable.

- Available facility capacities = 50 t/day or 100 t/day.

- Capital costs for facilities (in year zero $):

First Period Second Period Third Period

50 t/day 2 M$ 1.75 M$ 1.5 M$

100 t/day 5 M$ 4.4 M$ 3.75 M$

- Collection/transportation and operating costs (in year zero $):

First Period Second Period Third Period

50 $/t 45 $/t 40 $/t

Recycling

- 40% of generated wastes are potentially recyclable.

- Available facility capacities = 100 t/day or 200 t/day.

- Capital costs for facilities (in year zero $):

First Period Second Period Third Period

100 t/day 8 M$ 7 M$ 6 M$

200 t/day 15 M$ 13.1 M$ 11.3 M$

- Collection/transportation and operating costs (in year zero $)

First Period Second Period Third Period

45 $/t 40 $/t 35 $/t

Incinerator (Waste-to-Energy)

- Residue flow to landfill = 30% of mass flow into the incinerator.

- Available facility capacities = 75 t/day or 150 t/day.

- Capital costs for facilities (in year zero $):

First Period Second Period Third Period

75 t/day 10 M$ 10 M$ 10 M$

150 t/day 19 M$ 19 M$ 19 M$

- Collection/transportation and operating costs (in year zero $)

First Period Second Period Third Period

50 $/t 50 $/t 50 $/t

Landfilling

- Collection/transportation and operating costs (in year zero $)

First Period Second Period Third Period

60 $/t 90 $/t 120 $/t

A municipality of 500,000 people is presently relying solely on an external landfill to satisfy waste disposal needs. The elected officials wish to develop an integrated waste management system, which will potentially require the development of a centralized composting facility, a materials recycling facility, and an incineration (waste-to-energy) facility. The materials not handled by these facilities will be routed to an external landfill along with residue from the waste-to-energy facility (external landfill is assumed to have no capacity constraints). Based on the given information, develop an approach to determine which facilities should be developed, when they should be developed, and at what capacity (assume that a facility will either not be developed, or developed at some capacity level that will stay constant for the remainder of the planning horizon, i.e., expansions of facilities are not be considered). The overall planning horizon is 15 years, broken into three equal periods of 5 years each. The municipality is assuming at-source waste reduction initiatives to occur over time, such that wastes requiring management at the 5 -year point will be 90% of the year zero level, and at the 10 -year point will be 80% of the year zero level (i.e., the wastes requiring composting/recycling/incineration/landfilling will be reduced over time). Assume all facilities to operate 365 days/year, and per capita waste generation at year zero to be 1.0kg/person/day. Capital expenditures on waste management facilities are limited by budget restrictions to $20 million (year zero $ ) in any period. Composting - 25% of generated wastes are potentially compostable. - Available facility capacities =50t/day or 100t/day. - Canital costs for facilities (in vear zero $ ): - Collection/transportation and operatine costs (in vear zero S): Recycling - 40% of generated wastes are potentially recyclable. - Available facility capacities =100t/day or 200t/day. - Canital costs for facilities (in vear zero $ ): - Collection/transportation and oneratine costs (in vear zero \$) 1 Incinerator (Waste-to-Energy) - Residue flow to landfill =30% of m ass flow into the incinerator. - A vailable facility capacities =75t/ day or 150t/day. - Canital costs for facilities fin vear zero $ ): - Collection/transportation and operating costs (in year zero S) Landfilling Collection/transportation and operating costs (in vear zero $ )