Old Mutual’s Cape Town head office, Mutualpark, is aiming for a Net Zero Water certification from the Green Building Council of South Africa (GBCSA), after officially going ‘off the water grid’ in August 2018, thanks to dedicated long-term efficiency and savings, and a massive blackwater filtration plant.
The 166 000 square metre office, which accommodates about 9 000 employees and contractors is one of the largest corporate offices in South Africa and becoming water neutral is a seriously impressive achievement.
After fine-tuning the Net Zero pilot tool, Version 1 of the GBCSA Net Zero rating tool is set to be launched towards the end of 2018. While the World Green Building Council’s Advancing Net Zero project – which has set the challenge worldwide – focuses only on carbon, the GBCSA has taken this further, considering the critical, interconnected environmental challenges South Africa faces. Hence there is also Net Zero certification available in the categories of water, waste and ecology in South Africa.
A Net Zero Water certified building is a highly water efficient building with reduced consumption, which also harvests, recycles and reuses water, so that the amount of water consumed is the same as the amount of water produced. Net positive buildings recycle or produce more water than is consumed.
Old Mutual national technical manager, Khiyam Fredericks explains that because of the overwhelming drought in Cape Town, design of the water filtration project came first, and once he realised the potential of the project, a decision was made to register the project for a Net Zero certification.
“My advice: don’t do projects to get certifications… do it because it is the right thing to do. The certification must be a bonus, not the goal. If you are chasing certifications, and it is achieved, what motivation is there to continually push boundaries and innovate new ways of doing things better,” says Fredericks, who along with his team, is passionate about constantly seeking improvement in operations.
If a Green Star SA rating shows a good commitment to sustainability and a good start for the journey, “Net Zero comes when you realise that the effort in a certain category has actually reached a level where the potential to totally offset your carbon, or water impact can be achieved,” adds Fredericks.
How Old Mutual became water neutral
Following the net-zero hierarchy of efficiency first, water-saving initiatives were introduced from 2016 and water consumption was reduced at Mutualpark by over 30% before introducing other major interventions.
The biggest of these interventions is the waste-to-drinking-water filtration plant. The team started piloting the blackwater plant in July 2018 and it is now fully operational as the campus’ main source of water.
“Our Water Filtration Plant, which has undergone rigorous testing was certified SANS 241 compliant by national and local governments, making the filtered water drinkable. It has the capacity to produce between 650 000 and 800 000 litres a day! Mutualpark’s average consumption is about 450 000 litres of water a day,” says Fredericks.
The pristine plant is one of very few blackwater treatment plants operating in South Africa, and besides its main role of water supply, it is proving to be an educational attraction. “The interest in this plant has been phenomenal. There has been a lot of training and education happening at the plant,” says Fredericks. Interested parties (and there are many) have been learning about how the plant operates and being shown that blackwater treatment is entirely possible.
Wastewater from all the buildings on the campus is sent to one location, and from that sump it is sent on to the wastewater treatment plant, where the blackwater goes through a number of processes, transforming it to non-potable greywater. The greywater is then sent to the water filtration plant where it goes through further strictly controlled filters (sand filtration, granular activated carbon filtration, ultrafiltration and finally reverse osmosis), bringing the water to crystal clear drinking quality.
Daily samples at each stage of the process are taken to ensure the highest quality of water is produced. However, one of the major challenges is dealing with the reluctance of people to drink the filtered water once they know that it is recycled water.
To reduce consumption, an employee waterwise campaign was started to increase awareness of the water crisis, with displays of dam levels and water usage and savings targets, as well as urging employees to conserve water at work and at home. Importantly, electronic meters were installed in critical water use areas to track misuse and trends, and also proactively manage any leaks.
Fredericks notes that by understanding Mutualpark’s total consumption and using the guidelines from the GBCSA’s Existing Building Performance tool, it assisted the team to track annual data, highlighting key changes and allowing them to motivate for practical and efficient improvements. “Building owners see added value knowing there is an ability for your predicted targets to align with actual figures, as we have found over time, behaviour influences consumption.”
Practically, aerators were installed on taps and shower heads and waterless hand sanitiser was made available, lowering water consumption. Water pressure was changed to reduce the length of flush time for all toilets and a greywater system to flush toilets was installed at the onsite crèche.
Fredericks explains that a complete overhaul of the HVAC system was possible as it had reached end of life. Where there were 23 chillers across the campus feeding each building with chilled water, the installation was centralised and with the two phases completed, almost 20 chillers were removed and replaced with five. “This is more efficient and resilient, it has resulted in major energy an operational savings,” says Fredericks.
The air-conditioning system was upgraded so that its waste water flushes the toilets. This will eventually mean savings of about 40% (or 20 000 litres) of water per day in the heat of summer. The air-conditioning units in the data centre were also upgraded to be air based and not water based.
A waterless carwash was introduced and the water-based carwash was upgraded with a water recycling plant that has reduced its water consumption by 80%.
In terms of irrigation of the sports fields and gardens, a treated effluent water feed was introduced. Locks have been installed on external taps and the fountains have been switched off temporarily, although the main fountain has recently started flowing again thanks to the water filtration plant.
The data collection phase for Mutualpark’s Net Zero Water certification has begun, and the company hopes to have 12 months of data by October 2019, to submit for certification. If Net Zero is achieved, sights will be set on Water Net Positive achievement.