Waste Collection of an archipelago zone - Periodic OVRP

Penghu, which is an archipelago zone, is one of the counties of Taiwan. In order to collect waste from all inhabited islands, the Penghu County government recruits fishing boats as collection vehicles. The boat will depart from its home island then collects wastes from other islands and end at the biggist island - Magone. All the wastes will be processed then ship to KaoHsiung by container ships for incinerating.

Since the fishing boat is departing from its home island and end at the Magone island, it makes the waste collection a Open-ended Vehicle Routing Problem (OVRP). In addition, the time horizon of the waste collection is one week (from Monday to Friday) so that it is a Periodic VRP as well. Thus, the problem can be classified as a Periodic OVRP.

I tried to solve a simple instance and the useful columns are
  1. id
  2. x coordinate
  3. y coordinate
  4. Not used
  5. demand (for a week)
  6. visit times
  7. Not used
Some assumptions made:
  1. The boat will stop at one predefined quay for each island(even though the island has more than one quays)
  2. Each time the boat serves an island, it will pick up demand/visit times amount of waste. For example, if one island's demand = 100, visit times = 2, means the island will be visited twice in a week and each time a boat will take away 50 unit of waste.
The visit patterns are listed as follows:
The parameters of the boat are: (Adjustable) The output file and the routes for each weekday is as follows.

Location of Penghu