It has already been said ...
Published by Martin Regelsberger
It has already been said here:
Step one is to look at your process.
- Do you use the most water and energy efficient washing machines? Investing in more efficient machines could be cost-effective compared to a larger wastewater treatment.
- What kind of softener do you use, fabric or water softener? If it is water softener, could you use rainwater as a soft water source?
- Why do you use chlorine for bleaching? Could you use peroxide?
- Are there direct reuse possibilities, e.g. storing the water of the last rinsing cycle and reusing it for the first rinsing of the next wash, storing the second rinsing and use it for washing without any treatment the next time? That would could your water demand roughly by half.
Step two concerns energy
How do you heat the laundry water? Do your machines accept hot and cold water? If not, install a respective device.
Some of the laundry water will be very hot. You can use a heat exchanger to preheat the next hot water with the water from the washing machine. Cool the wastewater down to less than 5°C above your cold water in the heat exchanger.
You can use solar collectors to top up the temperature to the final level.
Step three is to treat the water for recycling.
Laundry water is not very polluted, which is partly a problem. You can treat it with vertical flow constructed wetlands with quite a small footprint if you have some space outside. Otherwise we had also good results with multi-stage floating bed reactors. The bed is made of foam cubes where bacteria can attach, which increases their age and concentration in your treatment containers. Constructed wetlands provide the same effect.
Step one is to look at your process.
- Do you use the most water and energy efficient washing machines? Investing in more efficient machines could be cost-effective compared to a larger wastewater treatment.
- What kind of softener do you use, fabric or water softener? If it is water softener, could you use rainwater as a soft water source?
- Why do you use chlorine for bleaching? Could you use peroxide?
- Are there direct reuse possibilities, e.g. storing the water of the last rinsing cycle and reusing it for the first rinsing of the next wash, storing the second rinsing and use it for washing without any treatment the next time? That would could your water demand roughly by half.
Step two concerns energy
How do you heat the laundry water? Do your machines accept hot and cold water? If not, install a respective device.
Some of the laundry water will be very hot. You can use a heat exchanger to preheat the next hot water with the water from the washing machine. Cool the wastewater down to less than 5°C above your cold water in the heat exchanger.
You can use solar collectors to top up the temperature to the final level.
Step three is to treat the water for recycling.
Laundry water is not very polluted, which is partly a problem. You can treat it with vertical flow constructed wetlands with quite a small footprint if you have some space outside. Otherwise we had also good results with multi-stage floating bed reactors. The bed is made of foam cubes where bacteria can attach, which increases their age and concentration in your treatment containers. Constructed wetlands provide the same effect.