Toray operates sewage reuse demonstration plant to alleviate water shortages in India

Multinational material manufacturer Toray Industries has started demonstrating a sewage reuse system employing its water treatment membranes in Chennai, India. The project starts from May 2023 through February 2026.

The nation’s swift urbanisation has caused water demand to surge in large cities.* Another challenge is that drought has beset around half of India. Toray estimates a water supply shortfall of 30-40%. Transporting water from other regions is also reportedly expensive. The authorities treat only around 30% of sewage, discharging most of it directly into rivers and other bodies of water, exacerbating water pollution.*

In April 2021, the Japan International Cooperation Agency (JICA) chose a Toray proposal to demonstrate and commercialise energy-saving sewage reuse systems in India that purify water with water-treatment membranes.

The selection was for that agency’s sustainable development goals (SDGs) business verification survey with the private sector for energy-saving membrane system for sewage reclamation in India.*

The company opened the Toray India Water Research Centre at the Indian Institute of Technology Madras (IITM) research park in August 2022.* The centre conducts joint research with the institute using water-treatment membranes for sewage reuse technologies. It also embarked on building a sewage reuse demonstration plant that recently became operational.

Fig. 1: Toray system’s two approaches to treat sewage

The first approach combines biological treatment with ultrafiltration (UF) and reverse osmosis (RO) membranes, while the second brings together membrane bioreactor and RO membranes (Fig. 1). Water filtered by UF membranes and membrane bioreactor is scarce of organic matter, particles, and microorganisms in sewage, and can be discharged into lakes and other bodies of water for indirect reuse as drinking water. RO membranes can also remove salts, heavy metals, arsenic, fluorine, and other contaminants to further enhanced reclaimed water.

Toray has engineered these offerings to consume 30% less power than conventional Toray-made counterparts. The company estimates that electricity rates have doubled in India over the past decade, making its energy-efficient system more attractive in that market.

The authorities in Chennai and Mumbai plan to reuse sewage with membranes from 2027 onwards. By demonstrating and promoting its system, Toray will contribute to greater sewage reuse in major Indian cities and help the nation address severe water shortages. This is also part of its sustainability vision, ‘Toray Vision 2030’, in which it plans to resolve water problems and materialise a circular economy by developing water treatment membrane systems.

*References are available upon request