Executive Summary – With all trucks, all trash is picked up in 4 shifts total, 1 full day and day shift of next day. Same number of shifts is needed if the contract trucks are not used.
Details
* Hundreds of thousands of people and hundreds of thousands of pounds of trash
* County has 40 trucks, contracts for 15 private trucks
* County capacity – 40 trucks * 9000 lb/truck = 360,000 lbs at one time
* Contract capacity – 15 trucks * 4500 lb/truck = 67,500 lbs at one time
* Clearwater Beach (356,000 lbs)
* Indian Rocks Beach (298,500 lbs)
* St. Pete Beach (96,800 lbs)
* Treasure Island (542,300 lbs)
* 60% recycled – recycling center an hour away
* 40% goes to landfill – 2 hours away from point, but hour away from recycling facility
* 8 gallons of gas one way to landfill, 4 gallons of gas to recycling center
* Complete cycle is : start at landfill, drive empty to a point to pick up trash (2hrs, 8 gallons), drive full to recycling center (1 hour, by division 4 gallons), drive 40% full back to landfill (1 hour, 4 gallons).
* Carrying too much gas on each trip. All that’s ever needed is 16 gallons plus incidentals. Weight of payload is 9000 or 4500 pounds. Weight of 8 unnecessary gallons of gas is about 64 pounds, so may not be completely trivial. Possibly worth it not to fill up each truck for each trip, just carry 16 gallons plus a reserve amount each trip.
* 40 county trucks require 360 county employees, 120 per shift
* 15 contract trucks require 30 employees, all on day shift (or at least only 8 hours per day).
* We can’t really say for sure how many trips each truck can make per shift or per day, because we don’t know how long they take to load or unload. Driving time alone takes up half of an eight hour shift, though, so there is probably no way any truck can make more than one trip per shift, without incurring overtime. For that reason, we’ll assume one trip per shift for each truck. This allows 4 hours for loading, unloading at two places and incidental paperwork, so is reasonable.
* So the contract trucks can process 67, 500 lbs per day (1 shift only), and the county trucks can process 360,000 lbs per shift, times 3 shifts, equals 1,080,000 lbs per day. Total daily processing capacity is the sum of the two, or 1,147, 500 lbs per day.
* Total trash at all points is 1,293,600 lbs (sum of 4 points)
* At end of one full day, all but 146,100 lbs (1293600 – 1147500) has been processed. Dividing by 9000, this load can be handled by 16.23333 trucks. To save money on blowtorches, etc, needed to come up with .23333 trucks, we’ll use 17 county trucks on the first shift of the second day to clean up the last of the trash. This leaves 23 county trucks to handle other duties and the contract trucks are not needed the second day.
* Will need 360 county employees and 30 contract employees first day and 51 county employees the second day.
Are the contract trucks really needed?
Without contract trucks –
· Total daily capacity is 1,080,000 lbs.
· Leftover trash after 1 day is 1,293,600 – 1,080,000 = 213,600 lbs
· Trucks needed on 1st shift, day 2 is – 213,600/9000 (rounded up) = 24 trucks
· Still easily able to finish in same number of shifts.
· Need 120 county employees first day and 72 county employees second day (no contract employees)
· May want to investigate other events, etc. to see if contract should be modified/eliminated.
Point by Point Summary –
· Clearwater Beach – Requires 356000/9000 – 40 trucks, 120 cty employees, 1 full shift
· Indian Rocks Beach – Requires 298,500/9000 – 34 trucks, 102 cty employees. Most of one shift
· St. Pete Beach – 96,800/9000 – 11 trucks, 33 cty employees, Partial shift
· Treasure Island - 542,300/9000 – 61 trucks, 183 cty employees, more than a full shift
Suggested Schedule (work some on all beaches every shift so one is not filthy all day)
Clearwater – 12 trucks each shift first day, 4 trucks second day
Indian Rocks – 9 trucks each shift first day,7 trucks second day
St. Pete – 3 trucks each shift first day, 2 trucks second day
Treasure Island – 16 trucks each shift first day, 13 trucks second day
Note that above schedule calls for 26 trucks on the second day, rather than 24. Some of these trucks are not full, so a few more are called for.
