How to ensure:
- Building and per capita reduction in water consumption (80% reduction in water use for toilet flushing), as a response to risk of water shortages in England/UK.
- Energy savings for external water supply networks generated by the reduced demand in buildings.
- Energy savings for wastewater collection/pumping/treatment and processing (reduced discharge rates from buildings).
- More efficient implementation of drainage systems in Retrofit Projects.
- Reduced aerosol from toilet flushing thus reducing spreading of viruses and bacteria
Vacuum drainage has been in use in the aviation, rail or marine industries (e.g. used on cruise ships), and the latest generation of the system is now also becoming an efficient and attractive alternative to traditional gravity drainage systems for both office and residential developments. Vacuum drainage systems transport wastewater by means of atmospheric pressure acting against vacuum.
Vacuum drainage from JETS offers significant water savings (80% less water compared to traditional toilets), thus reducing the building’s total water consumption. Additionally, vacuum drainage systems can operate using rainwater or recycled grey water collected from showers, baths and washbasins, eliminating the use and cost of fresh water for toilet flushing. As the vacuum toilet is flushed, some volume of air is being extracted from the toilet area which results in elimination of aerosol/toilet plume. Vacuum toilets not only contribute to water savings but also reduce spreading of infections. This is line with the UN SDG target for safe and sustainable sanitation.
Energy savings are also generated from vacuum drainage usage – as less water is being used in the building, significant energy savings can be generated on the infrastructure water distribution. Reduced wastewater discharges mean also that the city sewer capacity is preserved, and smaller volumes of wastewater are to be treated at the sewage treatment plants, which also contributes to reduction in carbon emissions and energy savings.
Reduced water consumption for the building or per capita can be calculated using recognised methodologies (e.g. BREEAM ‘Wat 01 Water consumption’ calculator). Carbon emissions reductions can be derived based on the reduced volumes for clean water and wastewater and utility company’s energy consumption reports.
For a typical office building (e.g. with the population of over 1000 people) the expected financial investment is orbiting at a similar or marginally larger capital cost compared to the traditional gravity drainage system. Workmanship and installation cost are normally lower (less and smaller size pipework is used on vacuum drainage systems).
Reduced water consumption and wastewater discharge rates generate financial savings on the Water Company bill and ROI are proportional to the building usage/occupation. Vacuum drainage systems involve maintenance of vacuum pump(s), but this normally offset by cost savings generated by the system.
Detailed calculations can be requested.
A copy of a report generated by an M&E and BREEAM Consultant and summarising the benefits of vacuum drainage can be found here: https://democracy.cityoflondon.gov.uk/documents/s74832/Bloomberg%20Issue%20Report%20-%20Appendix%204.pdf