Guwahati, Oct 05:Indian Institute of Technology Guwahati have developed an innovative nature-based wastewater treatment system to treat highly polluted swine wastewater. This low-energy and compact technology uses taro plants and an engineered ‘zig-zag flow’ design.
This new technology offers a promising solution for decentralised livestock farms, particularly in rural and resource-limited regions where conventional wastewater infrastructure is often impractical.
The research was carried out by the Waste Management Research Group in Department of Civil Engineering, IIT Guwahati. It intends to address a fastest-growing environmental challenge arising from expanding livestock production, which is the safe management of nutrient-rich and pathogen-laden piggery wastewater before it enters rivers, lakes and the agricultural ecosystems.
This study demonstrates how engineering innovation can boost the performance of natural wetland treatment systems. Swine wastewater used in the experiments was sourced from ICAR–National Research Centre on Pig (ICAR-NRCP), Assam, under an R&D collaboration with IIT Guwahati.
Beyond piggery wastewater, the engineered wetland concept could be adapted for other decentralised agricultural and rural wastewater treatment applications, contributing to cleaner water bodies, reduced nutrient pollution and improved environmental sustainability.
The findings were published in the Journal of Environmental Management (https://doi.org/10.1016/j.jenvman.2026.130466)(Impact Factor- 9.2), a peer-reviewed international journal published by Elsevier that focuses on environmental sustainability, natural resource management and related topics. The paper was co-authored by Mr. Monish Goswami, Mr. Sandip Ghosh and Prof. Ajay S. Kalamdhad from IIT Guwahati
Highlighting the unique aspects of this research, Prof. Ajay S. Kalamdhad, Department of Civil Engineering, IIT Guwahati,
“Our Research Team not only wanted to reduce pollution indicators but also to make wastewater biologically safer for the environment. We have demonstrated a compact and energy-efficient solution that could be adapted for decentralised livestock farms by engineering the movement of wastewater and combining it with the natural treatment abilities of plants and microorganisms.”
The research team’s next objective is to scale the laboratory-scale innovation for long-term field validation, with the vision of making sustainable, low-cost wastewater treatment accessible to decentralised livestock farming systems across India.
Highlighting some of the unique aspects of this research, Monish Goswami, PhD Scholar, IIT Guwahati, added,
“Unlike conventional constructed wetlands where wastewater flows directly through the treatment bed, our system incorporates ‘internal baffles’ (built-in partitions) that force wastewater to travel along a longer zig-zag pathway and undergo aerobic-anoxic transitions. This increases the contact time between wastewater, plant roots, beneficial microorganisms and gravel media, allowing multiple biological and chemical treatment processes to occur more efficiently.”
The technology has significant potential for decentralised livestock wastewater management, especially for small and medium-sized pig farms located away from centralised treatment facilities.
Its key advantages include:
- Passive, low-energy operation with minimal maintenance requirements
- Compact design suitable for rural and distributed livestock farms
- Use of locally available plants and gravel-based treatment media
- Simultaneous removal of organic matter, nutrients, metals and pathogens
- Potential for restricted irrigation and other non-potable water reuse, subject to regulatory compliance and further validation
‘REDUCED ORGANIC POLLUTANTS’
The engineered wetland substantially reduced organic pollutants, nutrients, suspended solids, metals and harmful microorganisms. The researchers observed a dramatic decline in microbial contamination, with total coliforms reducing from about 60,000 to 1,200 MPN per 100 mL, while E. coli levels dropped from around 2,200 to 350 MPN per 100 mL. The taro plants also thrived within the treatment system, with shoot length nearly doubling and biomass increasing more than fourfold during the study.
The focus on toxicity reduction was a distinctive aspect of this study. In order to determine if treated wastewater was still hazardous to living things, the researchers used a widely-recognized Allium cepa bioassay in addition to traditional wastewater quality analysis.
The treatment not only reduced pollutant concentrations but also the biological risks associated with wastewater reuse, as seen by the significant reduction in phytotoxic and cytotoxic effects.
