The first question that springs to mind is how long it takes to recoup the cost of the equipment. The honest answer is that it depends on the model and the sector, and that the usual range is between one and three years. But that range isn’t much use if you don’t know which costs to include in the calculation, and that’s where most estimates fall short.
What almost everyone says
1. The waste management company’s invoice
This is the most obvious item and is usually the largest. Collection, transport and treatment of organic waste. It is worth looking at the trend over the last three years, not just the current figure: this is a cost that tends to rise.
2. The containers
Rent or mortgage repayments, and regular cleaning and disinfection.
What is often overlooked
3. The cold
This is the item that is most often left out of the calculation. In many facilities, cold stores are kept running for the sole purpose of preventing organic waste from decomposing before the lorry arrives. That means 24-hour electricity consumption, maintenance of the refrigeration equipment and, above all, square metres of cold store space occupied by waste rather than produce.
4. The space
Container area, manoeuvring area, quay. In an urban location, the price per square metre is very specific.
5. Staff hours
Taking out the rubbish, bringing bins out and putting them back, cleaning the area, liaising with the refuse collection service. It doesn’t appear on any invoice, but it’s paid as part of your salary.
6. Pest control
Stored organic waste attracts rodents and insects. Pest control contracts exist largely for this reason.
And in the other column
A digester is not free to run. For the calculation to be accurate, its own costs must be deducted:
- Electricity. The DR300 has a power consumption of 8.6 kW/h and a total power output of 2,100 W at 230 V.
- Water. 936 litres per day, with an inlet water temperature of between 30 and 35 °C.
- Consumables. The 3-litre liquid enzyme kit lasts for around 6 months; the 210 litres of Biorgmax medium lasts between 2 and 3 years.
- Maintenance. Minimal, but not zero.
- Installation. 15 mm Ø water inlet, 65 mm Ø drain and electrical connection with a 3 × 2.5 mm H07 RN-F cable.
It is advisable to check beforehand that the installation supports these connections and that there is space for a unit measuring 1,562 × 980 × 1,332 mm and weighing 450 kg when empty. All figures are in the technical specifications.
A note on the figures you’ll see
Be wary of any payback period calculation that hasn’t first asked you two questions: how many kilos of organic waste you produce each day, and what type it is. Without those two pieces of information, any timeframe they give you is just a generic figure from a brochure.
If you could provide us with your sector and your estimated volume in the form, we’ll send you a quote based on the figures you’ve provided.
