This article talks about technologies being implemented for extensive treatability tests to offer efficient solutions to treat water and wastewater.

One of the key challenges industries face today is fulfilling their freshwater demands. As per the World Bank’s estimate, the present industrial water use in India is about 13 percent of the total freshwater withdrawal in the country. Water demand for industrial uses and energy production will rise at a 4.2 percent annual rate, from 67 billion cubic metres in 1999 to 228 billion cubic metres by 2025.

This creates space to set up treatment facilities for water recycling and reduce dependency on conventional sources. Zero Liquid Discharge (ZLD) is an effective wastewater management system that ensures net-zero discharge of industrial effluent into the environment. This can be achieved through recycling, recovering and reusing the treated effluent. However, sustainable operations of recycling and ZLD are not easy for various reasons, such as changing water quality, operational costs, and related uncertainties.  

Various industries have installed ZLD plants to recover the wastewater generated. However, operating teams may face challenges while achieving the desired performance for the following reasons: 

• Ageing infrastructure 
• Changing wastewater quality and quantity 
• New streams are being added due to changing product mixes. 
• presence of complex, emerging constituents 
• Unexpected events and uncertainties associated with operations and feed

To overcome these challenges, customised plant audits will be helpful. These audits will not only help to find solutions for a specific case, but also prevent any unforeseen events that may arise in the future. The findings from the audit can be used to reduce operational costs. Audits can help to formulate efficient ways to upgrade the existing treatment. Plant audits are useful when there is a need to decide whether retrofitting new technologies or revamping existing ones can solve a problem. Thermax provides expert services such as plant audits, treatability tests, pilot testing, and membrane autopsy. 

These services are crucial in identifying wastewater characteristics, design challenges, and providing innovative as well as cost-effective solutions to modern-day challenges associated with existing treatment schemes faced by industries.

Treatability studies are effective in understanding wastewater, its behaviour, and suitable treatment alternatives. It helps in optimising chemical consumption and dosages required for treating wastewater, which reduces the operational costs. Pilot testing, on the other hand, is suggested to minimise uncertainties while treating complex effluent streams. For example, one of the largest steel manufacturing units was generating wastewater from coke oven operations. The wastewater was treated to a certain extent and reused for quenching. The customer had expanded the production capacity and wanted to comply with stringent marine discharge standards. An expert team from Thermax carried out extensive treatability tests, and an efficient solution was offered.

Membranes are widely used for MF, UF, and RO applications for recycling plants. Any change in water quality or operational conditions can have an impact on membrane life, plant performance, and operational costs. Sometimes, due to unforeseen events, the membrane may get damaged. Thermax conducts membrane autopsies to recover membrane performance. This is an important step in understanding membrane health and the reasons for reduced performance. Thus, the repetition of such events in the future can be avoided.

These customised services play a vital role in ensuring smooth operations and reducing the risks of operational failures and losses. Customers can achieve and sustain desired performance from existing assets by utilising these services. 

Expertise shared by: Anupam Pathak, Process Engineer-R&D, Thermax Limited