ROC Water Technologies
Category: Circular Economy
Prize Awarded: R1,000,000
Company Overview
ROC Water Technologies is a technology enterprise based in Pretoria, Gauteng, South Africa, focused on innovative and sustainable wastewater treatment.
What the company does: The company specializes in resource recovery from highly saline wastewater, particularly acid mine water and hazardous material wastewater. It focuses on converting toxic industrial effluent into clean water and valuable commercial by-products.
Core mission and value proposition: The core mission is to promote resource recovery, aligning with the principles of the circular economy where waste is minimized and resources are efficiently utilized. The value proposition is delivering an efficient, environmentally friendly, and cost-effective solution for saline wastewater management, offering important advantages over traditional methods like evaporation ponds or biological processes.
Key problem they solve: The technology addresses the challenge of recovering valuable resources from wastewater effectively, minimizing the environmental footprint associated with traditional wastewater treatment. Specifically, it solves critical issues related to brine disposal (which is often illegal under current environmental management acts) and scaling challenges often encountered in Reverse Osmosis (RO) desalination processes.
Technology / Solution Description
ROC Water Technologies utilizes Pipe Freeze Crystallisation (PFC), a distinctive type of Indirect Freeze Crystallization (IFC). PFC uses controlled freezing to achieve phase separation, enabling the selective recovery of valuable resources from wastewater streams. The experimental setup involves a chiller, cooling reactor, and clarifier to facilitate the brine-treatment process.
Unique features and differentiators: PFC transforms toxic acidic mine water and industrial effluents into potable quality water (in the form of clean ice/water) and commercially valuable by-products such as and salts. Unlike some conventional freeze crystallization systems, the PFC method developed by the company avoids the mechanical complexity and wear associated with scrapers. It operates with a low energy requirement of 330 kJ/kg of water treated, which is significantly lower than thermal processes like distillation (2200 kJ/kg).
Technology Readiness Level (TRL): The technology is post-prototype, demonstrated through involvement in small-scale pilot plants at A-Thermal/ROC Water Technologies and coal mines in Mpumalanga.
Impact and Market Relevance
Who benefits from the solution: Industries generating high-salinity wastewater, particularly those involved in mining (dealing with acid mine water), industrial manufacturing, and hazardous waste management. It also benefits the public by recovering clean water for domestic and industrial purposes.
Social, economic, or environmental impact: The technology directly addresses South Africa’s critical water security and environmental rehabilitation needs. It is economically viable, incurring a total running cost of ZAR 496.67/t compared to ZAR 2,500/t for disposal at toxic waste sites, presenting a substantial cost advantage. The recovered sodium sulfate is 84.9% pure.
Achievements & Milestones
• SA Tech Challenge 2025: Winner, 1st Place (R1,000,000 prize).
• Previous Recognition: Received the grant for the 2021 NSTF-South32 innovation award.
• Patents: Developed the Pipe Freeze Crystallization technology with patent registration (RSA No: 2019/03795).
• Deployment: Successfully operated a pilot demonstration plant in Olifantsfontein, South Africa, for over four years.
• Research Breakthroughs: Demonstrated the ability to increase purity from 50% to 84.9% through operational optimization, including extending pipe length and increasing diameter.