Whether a recycling unit pays off is a sum, not an opinion. You need three numbers: what you pay per cubic metre of disposal, what you pay per cubic metre of fresh water on site, and how many cubic metres the bore consumes.
The sum
Take a 600 m bore with a 20 inch product pipe. That consumes roughly 500 m3 of fluid over the pilot and reaming passes. Disposal in the Netherlands costs 35 to 60 euros per m3, water hauling 8 to 15 euros per m3. Without a recycler you pay for all 500 m3 twice: once in, once out.
With a recycler returning 65 percent, you dispose of 175 m3 and haul 175 m3. At 45 and 10 euros that is a saving of about 17,000 euros on one bore.
What the recycler returns
- Sand and gravel: 70 to 75 percent
- Mixed ground: 60 to 70 percent
- Heavy clay: 50 to 60 percent, because fine clay passes the screens
Rent or buy
A recycling unit for a 250 tonne rig costs between 60,000 and 120,000 euros. Renting runs at 400 to 700 euros per day. If you drill more than 25 days a year with bores over 300 metres, buying is cheaper within two seasons. Below that, rent.
The catch
A recycler needs a crew member who watches the screens. On a site where nobody owns that job, the unit clogs, the crew bypasses it and the saving is gone. Plan the person before you plan the machine.