Testing the impact of HyBatchTM Reverse Osmosis technology on vertical farming as a step towards Zero Liquid Discharge (ZLD)
12th February 2024
Introduction
Agriculture is the largest global consumer of freshwater. Vertical farms—agriculture systems using vertically stacked growing layers—can dramatically reduce water consumption by 70% to 90%, significantly decreasing nutrient and fertiliser use. The ultimate goal in vertical farming is Zero-Liquid Discharge (ZLD), a fully closed-loop system recycling all water and nutrients.
Innovating Towards Zero-Liquid Discharge
GrowUp Farms, in collaboration with Salinity Solutions, has recently embarked on an innovative project funded by Growing Kent & Medway (GKM). Their aim: to trial Salinity’s novel HyBatch™ reverse osmosis (RO) technology, testing how effectively wastewater can be recycled in vertical farming to achieve ZLD.
Trial Objectives
The partnership’s goal was to assess the feasibility of recycling four wastewater streams from GrowUp Farms’ vertical farm operations to food-safe standards:
- Rainwater
- Farm irrigation flush-down
- Tray wash water
- Brine from existing RO systems
Combined streams were also tested for comprehensive effectiveness.
Ensuring Food Safety and Energy Efficiency
GrowUp Farms emphasizes maintaining the highest food safety standards. Recycled water must be at least equal in quality to mains potable water. Additionally, the trial assessed energy efficiency, ensuring enhanced water recycling didn’t negatively impact energy consumption.
Key Trial Activities
The trial occurred at GrowUp’s vertical farm facility in Sandwich, Kent, evaluating:
- Energy consumption and water recovery rates: Measured and compared against alternative technologies.
- Chemical and microbial safety: Independently analyzed, ensuring adherence to food safety standards.
Technology Spotlight: HyBatch™ Reverse Osmosis
Salinity Solutions’ patented HyBatch™ RO technology significantly outperforms traditional systems:
- Energy Efficiency: Uses over 50% less energy due to dynamic operational pressures.
- Waste Reduction: Decreases waste volumes by up to 80%.
- Higher Recovery Rates: Achieves up to 98% freshwater recovery, removing contaminants including nutrients, pathogens, microplastics, and PFAS.
- Compact and Portable: Delivered in a rapidly deployable 20-foot container.
- Chemical-Free Operation: Environmentally friendly, complementing natural water solutions.
Results and Benefits
The trial demonstrated impressive outcomes:
- Up to 98% water recovery from wastewater.
- Produced water cleaner than local mains water.
- Specific Energy Consumption (SEC) between 0.99-1.3 kWh/m³, 50-72% more energy-efficient than traditional technologies.
- Potential to reduce mains water use by 38%, significantly aiding water-scarce regions.
- Possible 32% reduction in GrowUp’s water-related operational costs.
- Achieved 33% decrease in wastewater discharge.
- Recovered valuable nutrients, such as phosphate and nitrate, for reuse as fertiliser.
Broader Impact and Future Potential
HyBatch™ technology promises significant environmental and economic benefits for industries beyond agriculture:
- Water Conservation: Minimises strain on freshwater sources.
- Environmental Preservation: Protects natural ecosystems by reducing pollutant discharge.
- Resource Recovery: Enables extraction and reuse of valuable nutrients and chemicals.
- Compliance and Sustainability: Supports adherence to stringent environmental standards and sustainability goals.
- Cost Reduction: Cuts operational costs through water and energy savings.
Recognition and Media Coverage
The trial gained significant recognition:
- Awarded ‘Water Efficiency Project of the Year’ at the Water Industry Awards 2024.
- Featured extensively across media platforms including BBC South East, BBC Online, The Engineer, Aqua Tech, Verticalfarm Daily, Materials World, and the (Don’t) Waste Water podcast.