A school in drought-stricken Cape Town has reduced its water use by more than 90% thanks to an innovative water-management system developed by one of the country’s leading firms of consulting engineers and environmental scientists.
Benjamin Biggs, a civil engineer and urban water-management specialist at JG Afrika, the firm behind the system, says that it is important to first focus on reducing water use before looking to supplement municipal supply with alternative sources.
According to Briggs the firm was able to implement immediate measures at the school that would yield outstanding results early on.
“Our experience in several other projects has demonstrated that this upfront work can play an important role in mitigating, or even eliminating the need for more costly and longer-term measures,” he says.Importantly, this step also helps drive changes in water-use behaviour in a water-scarce country.
Identifying high impact areas
About 400 people, including educators, administrative staff and students participated in the initiative, starting with basics such as flushing toilets sparingly and reporting water leakages.
These interventions were selected based on the findings of the baseline assessment, which combined historical information including utility bills, as well as physical inspections of the plumbing fixtures and equipment.
The outcome was used to model water flows to understand end-use quantities for various applications and determine the site water balance, which is the flow of water in and out of a system. This allowed the firm to identify high impact areas to address and assess possible solutions to reduce municipal water use on campus.
No major refurbishments required
As part of the first phase of the programme, all toilet flushing devices were replaced with water-saving mechanisms, and similar interventions were taken at other existing plumbing fixtures, including leaking washbasin taps.
Another technology implemented in many of the initial phases of JG Afrika’s other projects is low-flow showerheads that provide as much as a 50% reduction in water use without forgoing the comfort of conventional fittings.
“We first ensure that we have identified all of the available so-called ‘low-hanging fruits’ available to us. Importantly, many of these technologies can be installed without having to make any major refurbishments to an existing building and can therefore be installed at a minimal cost to the client,” Biggs says.
The next phase of the programme will entail installing a rainwater-harvesting system with treatment at the school. Water tanks are used to store harvested rainwater where after is it treated and pumped for use in applications, such as toilet flushing, irrigation and topping up the swimming pool.
Combined with those actions undertaken during the first phase, the system will reduce the school’s reliance on municipal water supplies by up to 95%.