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Innovative technology for odour control in Indian paper mills - application of chlorine dioxide can unlock higher productivity, profitability and sustainability

The technology has been developed as part of a project for the Indian paper industry under the Facility for International Cooperation for Inclusive and Sustainable Industrial Development (FIC-ISID), an initiative of the United Nations Industrial Development Organization (UNIDO) with support from the Department for Promotion of Industry and Internal Trade (DPIIT), Ministry of Commerce and Industry, Government of India; and being implemented in close cooperation with the Central Pulp and Paper Research Institute (CPPRI) as well as national and regional paper industry associations. The overall objective of UNIDO’s assistance to the industry is to boost the productivity and competitiveness of Indian pulp and paper mills, and therefore, enhance its global competitive position.

29 April 2022, Chennai: Odour has been identified as one of the major challenges in the recycled waste paper-based mills, particularly the mills producing unbleached variety of packaging grade paper. The Indian paper industry is highly water intensive, and to minimize its usage of fresh water due to its limited availability and applicable norms, most mills operate under a closed water circuit, a system that does not discharge any liquid. Owing to zero liquid discharge, the water is continuously reused within the system, which in turn, leads to increased water temperature and decrease in the dissolved oxygen level – conditions that are ideal for microbial growth and slime. The growth of aerobic and anaerobic microbes during the production process causes a marked odour in the final paper products and also shoots up the downtime due to paper breaks in paper machines, thereby affecting the product quality, productivity and revenue of paper mills.

To overcome this challenge, an innovative technology, in the form of the application of chlorine dioxide, a broad-spectrum and ecologically compatible oxidizing biocide was tested at Vamshadhara Paper Mill, Thiruvalluvar, Tamil Nadu under FIC-ISID’s paper project. The pilot demonstration started in July 2021 with support from an international technology supplier, Grundfos, as well as testing support from the Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Chennai.

The results, shared during a UNIDO’s dissemination workshop on 29 April 2022, have been quite encouraging, indicating the current option as techno-economically viable odour-control solution with positive impacts on product quality and overall productivity. Application of chlorine dioxide- based treatment contributed to reducing the microbial count (anaerobes and aerobes) by more than 99 percent within three months, from a population range of 10^7 or about a crore to less than 10^3 or 10^4, resulting in significant control of unpleasant odour and slime. Another parameter, the volatile fatty acids, the reason for odour in the system, was monitored in both the water and paper samples, and it too showed a marked reduction.

Giving an overview of this novel intervention under the paper project, Dr. Rene Van Berkel said, “Resource efficiency to minimize wastage and cleaner production in paper mills has been the focus of the project since its inception. The application of odour control technology, currently being demonstrated at Vamshadhara Paper Mill in Thiruvalluvar in Tamil Nadu, is a typical example of the triple bottom line benefits that we’d like to see in the future.”

Elaborating further on this successful intervention, Dr. M. K Gupta, Director, CPPRI said, “Many solutions have been suggested to stop the odour but these options have not been found economical and effective. Chlorine dioxide, on the other hand, has been found to be effective across a broad range of pH and it also oxidises a number of odour compounds into odourless compounds. We intend to transfer this technology to more mills, and very soon, we’ll see a replication of this technology in many of the mills in India.”

Due to its faster microbial killing rate, chlorine dioxide can prove to be an effective alternative to the conventional chemical products (biocides and dispersants) currently being used by the Indian paper mills. What also sets the technology apart from other prevalent practices is its cost-effectiveness. Explaining this further, Mr. Anil Kumar, Sr. Vice President IARPMA & Former Executive Director, Shreyans paper industry said, “I’m very happy that finally a technology has come that is cost effective and within the reach of all the paper mills. Cost of operations is quite less. It is safe to use, payback is very fast and microbial count has become non-existent. It could be used more widely when it is offered to industries.”

In addition to being cost-effective, the technology, as highlighted by Aravind Kulkarni, former Director, CPPRI and Board Member, Bharatiya Reserve Bank Note Mudran Limited, is also environmentally compatible. “This environmentally-friendly technology is directly related to the community, and will help in the sustainability of the paper industry. I’m sure that this demonstration of technology will become a reality in terms of commercial exploitation by the industry,” he said. The trial also showed up other interesting findings. Dr. R.K. Jain, Technical Expert, UNIDO pointed out that chlorine dioxide is capable of killing not just the odour-causing anaerobic microbes, but also the aerobic microbes which are responsible for slime in the paper machine. The technology, he further added, has the potential to reduce paper breaks, and in turn, improve the quality of paper.

India is among the fastest growing pulp and paper markets in the world and the local industry is among the top global producers. The sector creates around 0.5 million jobs directly which further demonstrates its significance for the economy. However, despite high demand for domestic consumption, the average capacity utilization rate is around 80%. Elaborating on how the project is working to bring about the change, Mr. R. Krishnaswamy, President, South Indian Kraft Paper Mills Association and MD, Sripathi Paper said, “In the first phase, technologies that could be replicated in India to achieve increased productivity and resource efficiency were identified, and in the second phase, these are being demonstrated at the firm level.”

Adding further, Mr. R. Krishnaswamy, President, South Indian Kraft Paper Mills Association and MD, Sripathi Paper said that paper industry is struggling for survival post covid because of issues such as wide fluctuation in raw material prices, abnormal hike in coal prices, international logistics challenges, etc. He highlighted that through the UNIDO project, the industry is gaining access to some feasible solutions.

The UNIDO project, aims to facilitate technology uptake and firm-level innovation, leading to increased productivity and competitiveness.