IN THE FIELD
Lowering energy costs for ZLD at a tannery effluent treatment plant in Ranipet, India
and soil pollution, and created a public health hazard for the local population. Disposing of the wastewater instead of treating it also meant that it could not be reused, requiring tanneries to continually draw water from the local supply. To avoid releasing toxic wastewater into the environment and comply with local discharge regulations, the Ranipet tannery effluent treatment built Ranitec CETP to treat as much as 4,500m 3 /day of effluent. One of the country’s largest effluent treatment plants for tannery wastewater, the CETP was designed with multistage RO systems to achieve zero liquid discharge (ZLD). This treats the effluent and delivers clean water back to the tanneries for reuse in their tanning process. THE SOLUTION Achieving ZLD can be an energy- intensive process, as it requires a final thermal treatment stage. By designing the system with multiple RO stages, the plant was able to reduce the volume of water that needed to go through the thermal stage and utilise ERDs in the RO stages in order to make them more energy-efficient. Ranitec CETP installed multiple skids incorporating Energy Recovery’s solutions for its multistage system. The plant utilised a full suite of product solutions, including the turbocharger, PX Pressure Exchanger (PX), Aquabold high-pressure pump, and circulation pumps. The PX is the
The textile industry is one of the largest consumers of water in the world, producing 4.6 billion tonnes of wastewater each year. That vast quantity of water — saturated with chemicals, dyes, and solids — presents a threat to local waterways. For environmental protection, water conservation, and public health, India — one of the world’s biggest textiles producers — is strengthening regulations on manufacturers. India is home to 18% of the world’s population but has only 4% of the world’s water resources, making it one of the most water-stressed countries in the world. Wastewater treatment allows for water recovery and reuse, reducing the strain on freshwater resources. However, treating textile effluent water is an energy intensive process and an additional cost burden on manufacturers.
The Ranitec Common Effluent Treatment Plant (CETP) was built in Ranipet, India, to treat effluent from 92 leather tanneries in order to comply with local regulations, prevent pollution of the groundwater, and provide a supply of clean water for the tanneries to reuse. By utilising a multistage reverse osmosis (RO) system with energy recovery devices (ERDs), the plant has been reportedly successful in treating of the tanneries’ wastewater while remaining cost effective. THE CHALLENGE Ranipet is an industrial town in Tamil Nadu, India, where multiple tannery manufacturing plants operate, processing hides into finished leather. Before the Ranitec CETP was built, tannery wastewater was previously directed to evaporation ponds for disposal. However, this method was ineffective at preventing groundwater
AquaBold high-pressure pump installed in the Ranitec CETP (Image: Energy Recovery)
30 Water & Wastewater Asia | September-October 2024
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