Water Purification with AquaRockBag® in the Johannesburg Area, South Africa

Introduction & Problem Statement

In an agricultural region near Johannesburg, local authorities were faced with a dual challenge: A small drainage channel discharged heavily polluted water from a nearby sugar plantation directly into a river, leading to significant environmental contamination and progressive erosion along the channel banks.

Earlier attempts using loose stones and gabions proved ineffective. These conventional methods failed to withstand the hydraulic forces, while offering no solution for the deteriorating water quality.

The Solution: AquaRockBag® Combined with Bimedia

A comprehensive and nature-based solution was implemented using 150 AquaRockBag® (2 tons each) filled with a custom mix of natural stone and biological filter media (Bimedia).

This newly created Biozone was designed to fulfil two core functions:

• Water purification: The bioactive filter media helps to break down organic residues from the sugar processing, improving the overall water quality.
• Erosion control: The weight and structure of AquaRockBag® dissipate hydraulic energy, protecting the channel banks and preventing further scouring.

Installation was completed on-site in just two days, with the bags filled close to the channel and placed directly into position – saving both time and logistics costs.

Sustainable and Cost-Effective Approach

Beyond its functional benefits, this approach offered clear economic and ecological advantages:

• Estimated cost savings compared to traditional erosion control methods: approximately €60,000.
• Ecological value: The porous structure of the AquaRockBag® promotes colonization by invertebrates and microbial life (e.g. Bio Discs), supporting the development of a healthy aquatic habitat.
• Aesthetically, AquaRockBag® blend seamlessly into the landscape – much more discreet than conventional structures like gabions or concrete walls.

Conclusion

• By using AquaRockBag®, the project delivered an innovative, fast, and sustainable solution that tackled two urgent challenges: improving water quality and reinforcing vulnerable banks. The successful implementation highlights how ecological restoration and engineering performance can go hand in hand – with rapid deployment, long-term impact, and reduced costs.