.jpg)
NIT Rourkela Researchers Create Cost-effective Biological System for Dairy Wastewater Management
Researchers from the National Institute of Technology Rourkela (NIT Rourkela) patented a new technology for a cost-effective, multi-layered biological treatment system, costing approximately Rs. 10,000, to treat dairy wastewater. This innovation (Patent No. 583949; Application No. 202431032506) has been conceived by Professor Kakoli Karar Paul, Department of Civil Engineering, along with Pragyan Das, a research graduate of the 2025 batch
The dairy sector in India is one of the world’s largest, and the processes involved in producing cheese, paneer, and yoghurt generate billions of litres of wastewater every day. This wastewater is typically laden with lots of fats, proteins, and carbohydrates and has a high Chemical Oxygen Demand (COD). The COD test determines the concentration of organic compounds in the wastewater. If such “COD”- laden wastewater is released into rivers or other water bodies without proper treatment, it consumes dissolved oxygen, which, in turn, results in the death of aquatic life and other ecosystems.
The existing treatment alternatives, such as membrane filtration, do not address the issues and are susceptible to severe clogging. The researchers at NIT Rourkela have designed a system that works with nature, is therefore affordable, and can be implemented without a large treatment infrastructure.
How the Five-Layer Treatment Process Works
Our patented system treats wastewater with five separate biological and physical layers. For layer one, maromicrobially active earthworm reactors consist of earthworms and macrophyte plants that aim to detoxify positively. Earthworms ingest and mechanically break down organic waste, thereby increasing dissolved oxygen levels in the water and providing a substrate for microbes to grow, stimulating further microbial activity. The macrophyte plants’ dense, fibrous root systems also help prevent clogging.
In layer two, the water passes through sand, which adsorbs the remaining solids, thereby filtering them. Each third layer consists of a fly ash pellet, which addresses residual pollutants and negative phosphorus. The gravel layer acts as a barrier, preventing the remaining biological contaminants from reaching the water.
A hydroponic root treatment plant of oxygen is submerged directly in the water, promoting biofilm growth and further decomposing the water. The biofilms break down the toxins, and the water improves in quality. The system was tested in a laboratory using actual dairy wastewater, and the water then passed tests for use as irrigation water and maintained negative phosphorus levels. The plants used in the system can also serve as fodder for cattle. The other systems can be used for the biogas and biodiesel.
What the Researchers say and Why it Matters
Professor Kakoli Karar Paul lucidly detailed the system’s manageable scale. She mentioned, “At a lab scale, the developed system is worth about Rs. 10,000 and has the potential to treat 30 litres of dairy wastewater on a daily basis. This capacity can also be increased as per need.”
Dr. Pragyan Das points out the relevance of the system to rural and semi-urban areas in India, which are devoid of any industrial wastewater treatment facilities. She noted, “With this system, we have designed an affordable solution to wastewater treatment, which can be easily deployed in areas where large-scale treatment infrastructure is completely or partially absent. By our natural treatment method, the wastewater is made fit for agricultural use; therefore, the impact on the environment and resource-based waste management is optimally addressed.”
A truly integrated approach, in contrast to the previous systems, has been followed here. Individually, methods like vermi-filtration, macrophyte-assisted treatment, and hydroponic purification are not novel, but by addressing clogging issues in conventional systems, this system has achieved higher pollutant removal efficiencies. This is what the agri-industrial system of the future, which focuses on sustainable development, requires.
Significance for Students and Future Researchers
This patent from NIT Rourkela is especially important for students of engineering and environmental sciences. It is an example of how civil engineering graduate students can use their imagination to develop a solution to a real and important problem. The fact that the research was conducted at an NIT and spearheaded by women scientists adds further meaning to a STEM research area that needs representation and can still be improved.
NIT Rourkela is ranked 13th in the NIRF 2025 Engineering Category and 34th overall and has been supportive of research that is applied and combines work done in a laboratory and industry. Students looking for a compelling, patient, and methodical case study to help them work towards a patent in environmental engineering, waste water management, and other forms of sustainable communication infrastructures and biotechnologies will be pleased to discover this research.
The heuristics for the design and optimisation of reactors for rapid treatment are the primary focus of the research team now. They are looking for industrial partners willing to adopt this technology and take it out of the confines of a controlled laboratory and into operational dairy technology.
Following updates from the NIT Rourkela Civil Engineering Department, reading the literature on vermi-filtration and hydroponic systems, and locating research internships offered at the NITs are very good steps toward participating in the evolving domain of India’s wastewater management.
Click Here for More Institutional Activities