IIT Roorkee develops ‘low-cost system to treat hydroponic wastewater’ | Dehradun News – The Times of India
Roorkee: Researchers at the Indian Institute of Technology (IIT) Roorkee have made significant strides in addressing the wastewater challenges associated with hydroponic farming. Hydroponics, a method of growing plants without soil using nutrient-rich water, generates wastewater that often contains high levels of nutrients such as nitrate, phosphate, and ammonia. If this wastewater is released untreated, it can lead to eutrophication in natural water bodies, resulting in harmful algal blooms and oxygen depletion, which threaten aquatic ecosystems.
The Innovative Solution
To tackle these environmental concerns, a team from the departments of Hydrology and Renewable Energy at IIT Roorkee has developed an indigenous, low-cost treatment technology that utilizes microalgal photogranules. This innovative approach has been documented in a study published in the international journal ACS ES&T Water.
Challenges of Conventional Systems
Traditional microalgae-based wastewater treatment systems encounter significant challenges, primarily due to the energy-intensive nature of harvesting microscopic algae from water. These systems often rely on expensive centrifuges or chemical additives to separate algae from wastewater. The IIT Roorkee researchers have addressed this limitation by inducing microalgae to self-aggregate into dense, spherical granules, which simplifies the harvesting process.
How the Technology Works
The newly developed technology employs a light-driven photogranule reactor, where microorganisms self-aggregate into dense spherical granules under controlled mixing and illumination. These granules comprise microalgae, bacteria, and cyanobacteria that work symbiotically to treat hydroponic wastewater.
Process Overview
- Introduction of Wastewater: Hydroponic wastewater is introduced into a controlled environment equipped with light and mild mixing.
- Photosynthesis: Under illumination, microalgae perform photosynthesis, absorbing carbon dioxide while assimilating nitrate and phosphate as nutrients for their growth.
- Degradation of Pollutants: Concurrently, associated bacteria degrade organic pollutants, significantly reducing both biological and chemical oxygen demand.
- Granule Formation: Over time, the microbial community produces extracellular polymeric substances that bind the cells together, forming compact green granules measuring approximately 4–6 mm in diameter.
Advantages of the System
According to Professor Sanjeev Kumar Prajapati, the principal investigator of the project, this new system offers several key advantages:
- Cost-Effectiveness: The granules naturally settle at the bottom of the reactor once mixing ceases, allowing for easy separation of treated water without the need for expensive mechanical or chemical processes.
- High Efficiency: Experimental results have demonstrated nearly complete removal of biological and chemical oxygen demand, with about 99% reduction in phosphate and ammonia levels, and nearly 90% removal of nitrate within a few days of treatment.
- Climate Mitigation: The system also shows substantial potential for carbon dioxide fixation, contributing positively to climate change mitigation efforts.
- Sustainable and Scalable: With low energy requirements, chemical-free operation, and simplified biomass recovery, this technology presents a sustainable and scalable solution for managing wastewater from the rapidly expanding hydroponics sector.
Conclusion
The development of this low-cost system by IIT Roorkee marks a significant advancement in sustainable agriculture practices, particularly in the hydroponics sector. As the demand for efficient and environmentally friendly farming methods grows, innovations like this one will play a crucial role in ensuring the sustainability of agricultural practices while protecting natural water bodies from pollution.
Note: The information presented in this article is based on research and findings from IIT Roorkee as of February 2026.
