JG Afrika helps alleviate pressure on Cape Town's strained water system

A school in drought-stricken Cape Town has reduced its water use by more than 90% and will continue working with JG Afrika to further mitigate its reliance on a strained municipal water-supply system.

We commenced work on the first phase of the school’s water-management project in November 2017 and completed it in December that year.

Initial measurements of the success of the water-saving interventions were undertaken between January and March 2018.

Already exceeding initial expectations, a further decision was taken by the school board to work with JG Afrika in rolling out similar programmes at its two other learning institutions in Cape Town.

Benjamin Biggs, a civil engineer and urban water-management specialist at JG Afrika, says that it is important to first focus on reducing water use before looking to supplement municipal supply with alternative sources.

Importantly, this step also helps drive changes in water-use behaviour in a water-scarce country, and he compliments the client for the proactive efforts already taken to use water efficiently before implementing a larger demand-side management (DSM) programme.

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.

We saved an additional 80% to the already low drought use by focusing on reducing high-use applications at the school. 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 us to identify high impact areas to address and assess possible solutions to reduce municipal water use on campus.

Prior to the programme, the school sourced as much as 1 064 kl/month from the municipality, with up to 70% of this water used to flush toilets in the ablution blocks.
During 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.

As part of this full turnkey service, JG Afrika works closely with select installers and plumbers, which were placed on standby during the baseline studies to ensure swift turnaround times.

Moreover, all of the water-saving technologies deployed in the programme have been tried and tested by the team of water experts at the JG Afrika office.

“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 it is 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%.
This strategy is in line with JG Afrika’s approach of first reusing all available water on site before abstracting from the groundwater aquifers.

The entire system can be installed in less than a month and therefore, can be operational ahead of the wet winter period in the Western Cape.

Depending on rainfall levels and irrigation requirements in summer, the school may pursue a third phase that will allow for water savings in excess of 95%. This entails installing a borehole on site to replenish stores of harvested water in the tanks.

The combined three phases will result in cost-savings of R150 000 per year under drought water restrictions and R450 000 per year under pre-drought conditions, while the school will be able to recuperate its investment in three years.

Information supplied by JG AFRIKA.