Introduction
With energy costs rising, it is important to address the question of running costs of a sewage treatment plant. To save you the time calculating the costs yourself, I have written this article to clearly lay out the costs. Given there are very energy efficient systems on the market that don’t run all the time, and others that have to run continuously, I will break down the cost difference between the two.
By “standard treatment plant", I am referring to a unit that runs continuously. Note, you cannot turn a treatment plant off overnight to save electricity.
Given the most common sizes sold are the 6 person (for up to 4 bedrooms) and 8 person (for up to 6 bedrooms), I will show the energy costs for both of those sizes. For reference, I am using the Premier Tech ASP, using a 75 watt blower for the 6 person and 90 watt blower for the 8 person respectively. Some systems may use a slightly lower rated blower (possibly down to 60 watts), this will give a slight reduction in costs.
At the time of writing (November 2022) I am using 34 pence per kWh.
| Wattage: | 75w |
| Price per kW (Nov 2022): | £0.34 |
| Running time per day: | 24hrs |
| Kwh Per day: | 1.8 kWh |
| Kwh Per Year: | 657 kWh |
| Yearly cost: | £223.38 |
| Wattage | 90 |
| Price per KW (Nov 2022) | £0.34 |
| Running time per day | 24hrs |
| kWh Per Day | 2.16 kWh |
| kWh per year | 788.4 kWh |
| Yearly cost | £268.05 |
An SBR system does not run all the time. The batch process of this style of treatment plant allows the system to be set to how many people are in the property. Therefore, the running costs vary depending on the number of people it is set to. Consequently, to show the power consumption, we have to break it down into the number of people using the system.
| Wattage | 75watts |
| Price Per KW | £0.34 |
| Population | Blower running Hours required (per day) | Total yearly kWh | Total yearly cost |
| 2 | 5.40 hours | 144.18 | £49.02 |
| 3 | 6.80 hours | 181.56 | £61.73 |
| 4 | 7.55 hours | 201.585 | £68.54 |
| 5 | 9.39 hours | 250.6685 | £85.23 |
| 6 | 11.23 hours | 299.7075 | £101.90 |
| 7 | 12.96 hours | 346.121 | £117.68 |
| 8 | 14.70 hours | 392.49 | £133.45 |
Now we have calculated the electrical costs for both styles of system, we can compare the two as follows:
Remember, the SBR system uses needs less energy if it is set to work for less people. Therefore, I have shown the costs based on the number or people using the system.
| Population (actual number of people in household). | Yearly energy cost for standard system (using 75 watt air blower for a 6 person system and a 90 watt blower for an 8 person system) | Yearly Energy cost for SBR system (using 75 watt air blower |
| 2 | £223.38 | £49.02 |
| 3 | £223.38 | £61.73 |
| 4 | £223.38 | £68.54 |
| 5 | £223.38 | £85.23 |
| 6 | £223.38 | £101.90 |
| 7 | £268.05 | £117.68 |
| 8 | £268.05 | £133.45 |
As you can see, the SBR system is the clear winner. Huge savings can be made if there are low occupancy in the property. This is clearly a factor that needs to be considered when choosing the right sewage treatment plant for any household or business.
"For a business where water is just from toilets and a sink, an SBR system can save a lot of money if set up and commissioned correctly for the flow coming in."
The graph below gives a visual representation of the cost comparison:
You may now be wondering which products are standard, and which products use the more advanced Energy efficient SBR method, here are some (but not all) of the systems:
SBR systems offer users much lower energy consumption and will save a lot of money in the long run. Without taking into account future energy price increases over a 20 year lifespan, a family of 4 would pay £4460 in electrical cost using a constantly aerating system vs £1500 using an SBR system. That is a £2960 saving.
I've provided a lot know free advice in the website. Which i really hope has helped you!
I'm doing some research and would like to know....