Abstract
In today’s industrialized world, not just treatment of industrial wastewaters is essential to protect ecology and environment, but providing safe drinking water is also a challenge. In view of these, the removal of contaminants, be it organic, inorganic or bio-contaminants, is a serious problem requiring various forms of technologies. The chemical industry requires unique techno-economical methodologies for different industrial sectors and for diverse nature of pollutants, low to high concentrations in effluent streams, for the desired extent of removal, foot prints in the assimilation of technology, less maintenance and flexibility of operations. The advanced oxidation methodologies that destroy organic pollutants to an extent of complete mineralization and hydrodynamic cavitation are gaining wide attention in this regard. CSIR-NCL’s new cavitation device vortex diode, which is based on vortex flow, is quite effective in destroying various organic pollutants and also harmful microorganisms from water. The applications can be many in industry sectors such as dyes and textile industry, pharmaceutical industry, fertilizer industry and also for drinking water treatment. The CSIR-NCL’s technology is now commercialized and is being successfully used in many industries.

Dr. Vinay Bhandari is a Chief Scientist in the Chemical Engineering & Process Development Division of CSIR- National Chemical Laboratory, Pune, with more than 32 years of research experience apart from 2 years of industrial experience. He has more than 300 publications/presentations, authored 2 books (“Industrial wastewater treatment, recycling and reuse”, Elsevier, 2014 and “Hydrodynamic Cavitation: Devices, Design and Applications”, John Wiley & Sons Inc., 2022), and filed 25 patents (12 patents  granted). He has developed 4 technologies based on hydrodynamic cavitation- for Disinfection of water (SWASTIIK); for Industrial wastewater treatment (commercialized in India/abroad) and for Desulfurization of fuels. He is recipient of several prestigious awards including Green & Sustainable Chemistry award, SERB-IGCW-2017 and IGCW-2023. His desulfurization work received GYTI award for Technological Innovation, conferred by the Hon. Vice President of India in 2019. He is also consultant to many industries specifically in the areas of Industrial wastewater treatment and Separation Processes.

Divya Dixit is a Research Scholar at CSIR-National Chemical Laboratory, Pune and has contributed to devising newer methodologies in water and wastewater treatment, especially in the development of dual activity and surface coted cavitation reactors that drastically enhance the efficiency of conventional hydrodynamic cavitation processes. She has published 6 research papers in reputed international journals and has won several awards including the prestigious Industrial Green Chemistry World (IGCW) award in 2023.

Introduction
W ater and wastewater treatment is a complex problem, especially when many new emerging pollutants are getting detected in the surface waters, causing harmful effects of various forms in living species and also on environment. In earlier times, when the volumes and locations of industrial the volumes and locations of industrial wastewaters were limited and nature of pollutants was well known, many common technologies such as coagulation to adsorption were quite useful in treating the wastewaters prior to the safe release/use. In recent times, many new organic pollutants have emerged in the form of specialty chemicals in sectors such as dyes/textiles, polymer industry, chemical fertilizers, pesticides, insecticides and due to increased use of pharmaceuticals, cosmetics and such specialty molecules. Many of the chemical industries are water intensive and generate huge quantities of wastewaters.

The advances in chemicals sector are driving occurrence of pollutants that are largely refractory in nature having difficulty in biodegradability and also are difficult to degrade using the conventional technologies. The problem of refractory pollutants is largely pertinent to industries generating less volumes of wastewaters such as pharmaceutical industries. The conventional thought process of characterising wastewaters in these industries in terms of only chemical oxygen demand(COD) and biological oxygen demand (BOD) can be quite inadequate and wastewater complexity can be quite severe compared to common chemical industry wastewaters. In known industry segments, the selection of technologies is largely on the basis of techno-economic feasibility using combinations of well-established technologies whereas for emerging pollutants removal, the selection is required specifically on the basis of treatability of wastewaters and newer technologies are essential, given the difficulties in the degradation of emerging pollutants using conventional methods.

The established effluent treatment technologies include charge-based separation methods such as coagulation, physical and physico-chemical surface forces-based methods such as adsorption, chemical methods such as oxidations, catalytic oxidations, photo-oxidations etc., size-based separation methods such as membranes and biological treatments of the type aerobic and anaerobic treatments. As a thumb rule, when the BOD contribution is high, the biological treatment is a good choice given the low cost of treatment. Sewage water treatment is one example where activated sludge process (ASP) is in use for over 100 years. For the treatment of high strength wastewaters, anaerobic treatment gives advantage in the form of generated biogas and efforts need to be made to have such increased value addition in the existing processes.

The commonly used coagulation – a charge neutralization process through the addition of coagulants such as inorganic or organic types that reduces the repulsive forces on the colloidal matter for forming agglomerates and thereby removal by simple settling- is quite useful in the part removal of pollutant load. The effectiveness of the coagulation process primarily depends on the nature of the coagulant and in most cases hybrid forms of coagulants are suggested for low sludge volumes, operation over a wide range of pH, fast settling and low cost. Chethana et al. reported significant improvements using appropriate combinations of bio-coagulants with conventional coagulants such as alum, ferric, and aluminium based coagulants to lower doses of bio-coagulants (up to one-third) and to increase acssus chemeng.5b 01553).

Adsorption, though, is a well-established process, the solution to environental problems for pollutants removal require slow-cost adsorbents, such as biomass derived adsorbents for high selectivity and without regeneration problems. Newer developments suggest use of biomass derived materials, nano-bio-composites, superpara-magnetic nanocomposites for easy separations and such adsorbents with multifunctional character for sustainable wastewater treatment or in effective removal of different organic pollutants, dyes and also for disinfection of water (Saumaya et al., 2018, https://doi.org/10.1016/j.jenvman.2018.08.028). Catalytic degradation processes, starting from Fenton oxidation, wet air oxidations, photocatalytic processes etc., typically have disadvantages in the form of suitable catalyst, real life applicability and generation of other hazardous by-products, apart from the cost of the catalyst and life.

For the removal of emerging/persistent organic pollutants, the conventional technologies largely have limited applicability. The removal methods, including membranes, have the biggest disadvantage as they tend to transfer problem from one point to other by generating secondary waste and therefore cannot be termed as sustainable technologies. In view of low concentrations of the emerging pollutants and high risks associated with these, even at low concentrations, destructive treatments technologies such as advanced oxidations processes and electro-oxidation have to be employed. Hydrodynamic cavitation here offers one specialized form of advanced oxidation without use of conventional catalysts. Hydrodynamic cavitation in recent years is getting extensively explored for various applications and appears to be highly promising in diverse applications such as biomass processing, desulfurization of transportation fuels, food processing etc. However, the most promising application of hydrodynamic cavitation appears to be in water and wastewater treatment. Recently, Ranade and Bhandari have evaluated applications of different methodologies in industrial wastewater treatment, including hydrodynamic cavitation (Industrial wastewater treatment, recycling and reuse, 2014, https://doi.org/10.1016/C2012-0-06975-X).

CSIR NCL’s Technologies for Water and Wastewater Treatment
Hydrodynamic Cavitation
Hydrodynamic cavitation is one important class of cavitation from real life applications point of view,the other less common forms being acoustic cavitation, particle cavitation and optic/laser cavitation. The cavitation technology, in general, implies formation of oxidising species and the generated oxidising agents help in the oxidative degradation of the organic pollutants. The technique is specific form of advanced oxidation process and is mainly applicable to the degradation of organic pollutants. Since the chemical industry has diverse nature and contributes to various forms of organic pollutants- from simple organic molecules to complex specialty molecules and emerging pollutants, the cavitation technology is highly relevant to the wastewater treatment problems of different chemical industries.

Hydrodynamic cavitation technology employs suitable mechanical cavitation device (reactor) for effecting sudden pressure drop and generation of cavities and for subsequent oxidation due to generation of hydroxyl radical through water splitting. The cavitating devices can be classified as those with moving elements (Rotor-stator type) and those without moving elements (e.g. orifice, venturi and vortex diode). The different types of reactors, the design details and theoretical performance evaluation in different types are well described in the recent book by Ranade, Bhandari et al. (2023) where different applications of hydrodynamic cavitation including that in effluent treatment are highlighted (Hydrodynamic Cavitation: Devices, Design and Applications, https://www.google.co.in/books/edition/Hydrodynamic_Cavitation/8L-XEAAAQBAJ?hl=en&gbpv=0). Though the cavitation technology was known for several decades, the practical real life applications are getting appreciated only recently and the readers may find the above reference highly useful in not just acquainting with the techniques, but also for exploring possible applications in the area of water and wastewater treatment.

Vortex Diode for Effluent Treatment
We, at CSIR-NCL, have developed water and wastewater treatment technologies based on advanced oxidation process – hydrodynamic cavitation where a specialized cavitation reactor was designed using vortex flow in cavitation, termed as vortex diode (US9422952B2, IN397769, EP2766314, PCT/IN2012/000676, US9725338B2, IN338553, PCT/IN2020/051007, WO 2021/111476 A1, US2021111476).The technology has been licensed to M/s VIVIRA Technologies, Pune and a large number of units of CSIR-NCL designs are presentlybeing used in different industries. The vortex diode is a simple mechanical device of specific design without any moving elements. It consists of a tangential inlet, circular chamber for vortex generation and an axial outlet. Water/wastewater stream enters tangentially into the chamber and forms a strong vortex. The design is such that there is a sudden pressure drop to an extent that part of the liquid flashes into vapor forming cavities or bubbles (Fig. 1).

The cavities are allowed to grow and finally to collapse in the designed manner. The collapse of the cavities, termed as implosion (opposite of explosion), generates extreme temperature (~10000 K) and pressure (~1000 atm) conditions at the point of implosion, causing water to split homolytically generating hydroxyl radicals. The hydroxyl radicals are highly oxidising species and oxidise the organic pollutants, envisaged results being complete mineralization, forming carbon dioxide and water. It has been observed that mineralization is common in hydrodynamic cavitation using vortex diode of conventional type, whereas, it can also results in formation of by-products apart from mineralization in vortex diodes having catalytic activity; though the number of by-products is typically much less than that observed in conventional catalytic degradation processes. However, these aspects need to be investigated in the preliminary experimental investigations for viability since there are no theoretical predictions available till date.
The vortex diode for effluent treatment has many advantages compared to most conventional devices in terms of high degradation efficiency, lower pressure drop and consequent lowered cost of operation apart from less/ no maintenance, less clogging due to large open area and easy scale-up up to 40 m3/h. The technology is useful for degradation and removal of variety of organic pollutants and thus for reduction in COD and ammoniacal nitrogen (Bhandari et al., 2021, https://doi.org/10.1016/j.ultsonch.2020.105306)

Fig. 1. Cavitation process and CSIR-NCL’s cavitation reactors for industrial applications Dual Activity and Surface Coated Cavitation Reactors for Water and Wastewater Treatment

The vortex diode as a cavitation reactor certainly offers significant advantages in terms of lower pressure drop, higher degradation efficiency, less maintenance and most importantly lower capital as well as operating cost compared to the conventional devices. However there are still limitations and the technology still finds difficult to present itself as a stand-alone technology to provide complete solution to wastewater treatment. Similar to the catalytic oxidation process, it would be instructive to add catalytic activity to the conventional cavitation without addition of the external catalyst. This philosophy was translated in the form of dual activity and surface coated cavitation reactors where the reactor itself could be catalytic metal or the internal surface can be coated with catalytic metal specific to the degradation of the pollutants (Fig. 2).

The proof of concept was successfully established by using copper vortex diode for the degradation of cephalexin where extraordinary enhancements in the degradation were observed due to catalytic action of copper in Cu-vortex diode compared to the conventional hydrodynamic cavitation under similar operating conditions, especially using process intensification with hydrogen peroxide (Dixit et al., 2023, https://doi.org/10.1016/j.cherd.2023.02.03). Similarly, the surface coated vortex diodes using the internal coating of catalytic metals such as copper and nickel were extremely effective compared to even the conventional vortex diodes for the degradation of various pollutants, and degradation to an extent of 100% could be accomplished within minutes. The new reactors clearly highlight the utility of the dual function cavitation reactors over the conventional devices for increased efficiencies and subsequently significantly reduced costs in industrial wastewater treatment. Also, the technology is suitable for destructive removal of harmful refractory pollutants,consequently providing sustainable processes for environmental pollution control.

Fig. 2. Transformation of Conventional Reactors into Dual Activity Cavitation Reactors

Applications of CSIR-NCL’s Vortex Diode Technology for Real Life Industrial Wastewater Treatment

Distillery Industry Wastewater Treatment
Distillery wastewaters are typically characterized with very high values of COD (>1,00,000 ppm) and high BOD (~50000 ppm or more). It also has high ammoniacal nitrogen content. Here, the vortex diode technology is quite useful in converting part COD to BOD to enhance the gas yield, to an extent of 20% based on the real industry data.For example, in one real life installation, and for distillery effluent characteristics of initial COD of ~125,000 ppm for the flow rate of 50 m3/h, and increase in the gas yield up to 22% was reported. The installation is simple, as can be seen from the Fig.3, where the effluent can be passed through the vortex diode using the suggested process conditions of pressure drop/ flow rate prior to sending to anaerobic digester. The technology is also useful for removal of ammoniacal nitrogen.

Fig. 3. Application of Vortex Diode for Distillery Wastewater Treatment

Pharmaceutical Industry Wastewater Treatment
Due to the advances in the medicinal field, many new API pollutants, whose regulatory status is largely unknown, have been detected insurface waters and also in the drinking water. The persistent and refractory nature of such emerging pollutants is dangerous to the ecosystem. The conventional treatment methods are largely inadequate to effectively remove these pollutants; their destructive removal is especially important in view of the hazardous nature of many of the pollutants even at extremely small concentrations. Vortex diodes and hydrodynamic cavitation is quite effective in this regard, but with process intensification. The efficiency of hydrodynamic cavitation was enhanced by introducing catalytic action within the cavitation reactor, either by changing the construction material or by coating the internal surface of the reactor with an appropriate catalytic metal.For example, degradation of ciprofloxacin using normal advanced oxidation methods and also conventional vortex diode yields only up to 20% degradation, whereas the surface coated dual activity vortex diode can yield 99% degradation using process intensifications of the type pH modification or hydrogen peroxide addition.

Recently, Dixit et al. (2023, https://doi.org/10.1016/j.cherd.2023.10.002) reported that copper and nickel coated vortex diodes can provide complete degradation of antibiotics such as Cephalexin andCiprofloxacin within just 5 min, the performance being far superior over the conventional reactors under similar operating conditions. The technology was also effective for the complete degradation of common diabetes drug, metformin using these surface coated cavitation reactors (2023, https://doi.org/10.1016/j.cep.2023.109572). In view of the high cost of treatment of the conventional methods including that for advanced oxidation processes and electro-oxidation, the developed vortex diode hydrodynamic cavitation technology can provide techno-economically viable solution at cost lower by an order of magnitude.

Fertilizer Industry Wastewater Treatment
Fertilizer industry has different units producing effluents with varying organic pollutants and their concentrations. Hydrodynamic cavitation using vortex diode was found to be highly effective in treating a stream of very high COD (> 1,00,000 ppm) where ~85% removal of COD was reported (2016, https://doi.org/10.1080/19443994.2016.1186399). The technology was also effective in the removal of ammoniacal nitrogen from various high ammoniacal nitrogen containing effluents of different plants. The use of dual activity cavitation reactors has not been reported so far on such effluents, but it can be expected that these can perform better than the conventional devices.

Dyes/Textile Industry Wastewater Treatment
Dyes and textile industries produce effluents many of which contain refractory pollutants. In view of the small to medium size of the industries and varying products of specialized nature, specific process integration methodology needs to be developed for lowered overall cost of ETP. The nature of the dye and characteristics of the wastewaters are critical to the success of the degradation methodology and preliminary evaluation at laboratory pilot plant scale is essential to assess the efficacy of the techniques, optimization of the parameters etc. Again, needless to mention, the new dual activity cavitation technology can be highly useful for degradation of reactive molecules. The low-cost hydrodynamic cavitation technology here can provide techno-economically feasible solution and can be easily integrated in the existing ETP.

Drinking Water Treatment
Safe drinking water is essential to living and for preventing waterborne diseases such as diarrhea, dysentery, typhoid, and polio. The recommendation of WHO, “The potential health consequences of microbial contamination are such that its control must always be of paramount importance and must never be compromised”(WHO, 2019, https://www.who.int/) is clear in this regard. While, there are physical methods such as heat treatment, UV disinfection, membranes etc., the chemical methods such as chlorination are largely prevalent with close to 95% use worldwide for water disinfection. The chemical methods have main disadvantages such as generation of disinfection by-products many of which are carcinogenic apart from ineffectiveness in eliminating all harmful microorganisms. We, at CSIR-NCL, have developed SWASTIIK technology for water disinfection- Safe Water and Sustainable Technology Initiative from Indian Knowledgebase, by integrating the ancient knowledge of Ayurveda and our indigenously developedhybrid hydrodynamic cavitation technology. The technology has the potential to offer alternative to existing disinfection processes, mainly chlorination with cost-effectiveness. The technology is effective in eliminating practically all the harmful bacteria, including antimicrobial resistant (AMR) bacteria (Mane et al., 2020, https://doi.org/10.1016/j.ultsonch.2020.105272.; https://doi.org/10.1016/j. ultsonch.2019.104820).

The developed technology is unique of its kind to successfully demonstrate the use of commonly used natural oils having antimicrobial activity, such as peppermint oil, ajwain oil etc., in a very low concentration of less than 0.1%. The combined impact of cavitation and oil results in complete and instant cell destruction through the rupture of cell wall, oxidative damage and possible DNA denaturation. The oil can be easily separated and recycled/reused. The estimated cost of treatment is believed to be ~Rs. 2.5/m³ or 0.25 Paise/L.The new dual activity cavitation reactors can also provide another useful and effective alternative to drinking water treatment without the use of any chemicals/oils. Thus, in view of low cost and ease of operation, the technology can be employed not only for the drinking water treatment plants, but also can be implemented for household/point of use applications.

Summary
Industrial wastewater treatment requires new advanced technologies for effective removal of the refractory pollutants and for increased cost-effectiveness. CSIR-NCL’s hydrodynamic cavitation technology and vortex diode, dual activity cavitation reactors and surface coated cavitation reactors offer indigenous technologies for wastewater treatment, providing promising alternative to many existing processes, mainly advanced oxidation processes. The surface coated vortex diodes can also provide potentially useful alternative to existing chemical methods such as chlorination for drinking water treatment. The developed technology alternatives are easy to implement, require less capital and operating costs, practically no maintenance and offer easy scale-up. It can be used for the degradation of pollutants, in isolation or in combination with many processes. It certainly can offer benefits in the existing effluent treatment plants for reduced operational costs apart from desired contaminant removal.

Wastewater as a source of energy should be considered where applicable for converting part COD into BOD and vortex diodes are highly suitable for the treatment of high strength wastewaters to enhance gas yield.The CSIR-NCL’s vortex diode and new dual activity/surface coated cavitation reactors can find wide applications in many industries such as for distillery wastewater treatment, pharmaceutical industry etc. in the form of techno-economically feasible solution to industrial wastewater treatment.

Acknowledgement
The authors, Dr. Bhandari and Ms. Dixit, would like to acknowledge the financial support from Department of Science and Technology, India and Council of Scientific and Industrial Research, India for the research in the area of water and wastewater treatment.

Abstract
Climate change, driven by greenhouse gas emissions and deforestation, stands as one of the most pressing global challenges. The urgency of addressing this crisis is emphasized by the fact that 2023 holds the record as the warmest year¹ for both land and ocean. Non-renewable sources of energy, such as coal, oil, and gas, contribute to nearly 75% of global emissions. Therefore, amidst the global push for carbon neutrality, the need to fast-track the adoption of end-to-end accurate and dependable emission management cannot be overlooked or delayed. India has committed to ambitious goals, with plans to achieve net-zero emissions by 2070 and meet at least 50% of the country’s energy requirements with renewables by 2030. With the right emissions measurements/monitoring followed by actions for emissions reduction in the manufacturing industry is an urgent global need.

Introduction

the primary source of greenhouse gas emissions in global industrial operations continues to be the consumption of fossil fuels, wherein carbon dioxide (CO₂) and methane play pivotal roles. The potency of methane is about 27-30 times more impactful than CO₂. Methane leaks are a significant contributor to climate change and a critical cost for business. In 2021, losses in the oil and gas industry cost a staggering $19 billion² There is a pressing need for effective measures for measurement, control, and reduction immediately to stem global warming in the future. Many industries currently lack a baseline for demonstrating year-on-year improvements in reducing emissions. Tracking and reducing emissions can improve process uptime through predictive maintenance, thereby reducing product losses across the entire process. This lack of transparency poses challenges for the environment, internal targets, regulators, investors, and other stakeholders.
There are two key challenges that effective emissions management face. Firstly – it is difficult for industrial companies to measure methane emissions and secondly, complexity of collection of the data efficiently from various sources. The need of the hour is end-to-end emissions management solutions in industrial settings that help measure, monitor, report, and reduce emissions. These solutions offer cost-effective and automated ways to navigate the green-energy switch playing a crucial role in controlling and reducing greenhouse gas Scope 1 emissions across oil and gas, refining, chemicals, power, metals, mining, and other process industries.

Key Drivers for Industrial Emissions Management
Emissions management will evolve in the next 5-10 years through policies, regulations, and incentives happening across the world. Governments around the world have implemented regulations and standards to limit and monitor emissions from industries and businesses. Consumers, stakeholders, and investors are increasingly interested in supporting sustainable and socially responsible companies, and the focus on reducing carbon footprint will increase. Companies will gain a competitive advantage by reducing their environmental impact, reputation improvement, and attracting environmentally conscious customers and partners. Reducing emissions can lead to cost savings that include energy efficiency improvements, waste reduction, and reduced regulatory compliance costs.However, there are also financial and reputational risks associated with emissions management, such as regulatory fines, legal liability, and negative media coverage.

What is Exciting about Emissions Management?
The prioritization of emission management extends beyond environmental concerns thereby affecting the reputation and business performance of industries. Firstly, over-reporting / incorrect reporting of emissions due to erroneous mass balance calculations can potentially add to costs while eroding reputation. Secondly, ineffective audit management makes it difficult to identify trends and reduce leaks, leading to fines and decreased profits.
Advancements in research and development have brought forth innovative solutions that offer an automated end-to-end approach, e.g. wireless greenhouse gas detectors rapidly detect and measure leaks, visualization, and trending tools support predictive maintenance, reducing plant downtime, while analytics pinpoint gas leak locations for maintenance and process optimization.

Emissions Management is a cost-effective, automated end-to-end solution to rapidly detect, measure, and locate gas leaks. With plant-wide and enterprise-wide visualization and reporting, it empowers operations to control and reduce greenhouse gas scope-1 emissions³.

• Approx. 25% of the global warming experience⁴ relates to methane emissions. The new tech helps in eliminating emissions. 1 kg of CH₄ emission reduction is equivalent to planting approximately 3 trees a year.⁵
• 2.3% of Extracted natural gas is leaked – The ready-now technology helps to detect leaks faster and continuous monitoring improves worker safety.⁶
• $19B accounts for leak losses in 2021 and losses increase year-on-year.⁷ The tech offers a shift from reactive to predictive maintenance enabled via software analytics and helps reduce leaks.⁸

Global organizations have come up with outcome-based offerings like enterprise emissions management software-as-a-service, gas detectors, cameras, and services. Our organization, Honeywell, is focused on this and has levers to help a facility decarbonize that include emissions management, accounting for the emissions, voluntary and mandatory disclosures showing the reduction over time to meet the key performanceindicators. We are engaged with customer pilot projects where our automation tools help to manage the equipment, processes and be energy efficient, and operate at their optimum. Apart from this, we are also working on solutions that identify the reasons and prevention of reoccurrence in the future belonging to industrial emissions management.⁹

By embracing these solutions, industries can not only meet their environmental responsibilities but also ensure sustainable and profitable operations in the face of an ever-changing climate landscape.
In conclusion, the battle against climate change demands collaborative endeavors from both the government and industries, with appropriate backing of cutting-edge process control technologies.
The relentless impact of greenhouse gas emissions, primarily driven by fossil fuel consumption, necessitates swift measures to curb CO₂ and potent methane emissions. The global shift towards carbon neutrality further highlights the pivotal role of advanced emissions management in steering the decarbonization journey.

References

1. [Climate.Gov] https://www.climate.gov/news-features understanding-climate/climate-change-global-temperature#:~:text=According%20to%20NOAA’s%202023%20Annu al,0.20%C2%B0%20C)%20per%20decade
2. Honeywell Process Solutions] https://process.honeywell.com/us/en/initiative/emissions-management-solution
3. [Honeywell Emission Management Solution] https://process.honeywell.com/us/en/initiative/emissions-management-solution
4. [International Energy Agency] https://www.iea.org/reports/global-methane-tracker-2022/methane-and-climate-change
5. [Honeywell News] [ Why Methane is bad] https://www.honeywell.com/us/en/news/2021/11/methane-what-is-it-and-why-is-it-bad
6. [Scientific American]https://www.scientificamerican.com/article/methane-leaks-erase-some-of-the-climate-benefits-of-naturalgas/#:~:text=A%20series%20of%20earlier%20 studies,by%20EPA%2C%20at%201.4%25.
7. [Honeywell Emissions Management Solution] https://process.honeywell.com/us/en/initiative/emissions-management-solution
8. OGM Partnership]https://ogmpartnership.com/wp-content/uploads/2023/02/10_Things_You_Need_to_ Know_about_Methane_21-11-20.pdf
9. [Honeywell Forge Sustainability Plus for Industrial Emissions Management] https://www.honeywellforge.ai/us/en/products/industrial-operations/honeywell-forge-sustainability-plus-for-industrials-emissions-management

Abstract
India’s fertilizer industry has transformed, ensuring food security for over half a century. Despite challenges like geopolitical tensions and climate change, innovations and policy support drive sustainable agricultural growth.

Introduction
Unlike other periods in contemporary Indian history there has been no famine in India during the past half a century. Agricultural production witnessed a steady increase from the 1970’s to the present (2023), which now stands at 329.7 million tons of grain production. In India, several factors contributed to this big achievement, the foremost among them being the use of mineral fertilizers in the farmlands. Globally, India is the second largest producer and consumer of fertilizers only after China.
As of now, the fertilizer manufacturing industry in India is a robust venture, utilization of installed capacities is good and the profitability of the business is also better. The situation was different just five years back when government subsidy was inadequate and that too not available to the manufacturing units in time resulting in heavy financial strains to maintain operations of the unit. Some major players left the scene as they found other investment options more lucrative.

Domestic Production
Urea, DAP, NP and NPK complex fertilizers, ammonium sulphate, potash and single super phosphate (SSP) are the major fertilizer products used in Indian agriculture. India has a high dependency on imported fertilizer raw materials, intermediate and products.

                   Table 1: Installed capacity and production of fertilizers

In India, farming and the production of food grains is not a big-ticket business being operated at industry level. Though there are large farm holdings owned by some houses, the bulk of the Indian farmers are small and marginal ones who cultivate for subsistence and sell surplus to the market. Therefore, there is a heavy dependence on government support system, which are available in the form of fertilizer subsidies and minimum support price for procurement of grain by the agencies in the government.

Table 2: Production, import and consumption of fertilizers

Food fertilizer and fuel subsidies constitute a big junk of government finances in the budgets presented to the Parliament every year. Following the Ukraine war and development of a troubled geo-political situation in the Middle East; there has been a complete disruption in the supply chain in the fertilizer industry.in the government from time to time and thus the government still has a say in fixing the prices of complex and potassic fertilizers.

Import of Fertilizers
The highest import dependence is for potash for which no domestic sources are available. Efforts are underway to recover potash from spent lye from the sugar industry and from seawater bittern. In the case of phosphatic fertilizers for which raw material (phosphate rock), intermediate (phosphoric acid) and finished products (DAP and NPK complex fertilizers) need to be imported from other countries. Available phosphate deposits in Jhamarkotra in Rajasthan contain only a lower P2O5 content suitable for making SSP only. Around 30% of the country’s urea requirement is met by imports. Every year the government earmarks a sizable quantum of foreign exchange for the above imports.

Fertilizer Subsidy
Under the Indian fertilizer subsidy regime, producers are asked to sell fertilizer materials (especially urea under the Retention Pricing Scheme – RPS) to the farmers at a price fixed by the government that is affordable to them. The price differential between cost of production together with a reasonable return on investment and the market realisation for every ton of product dispatched from the plants is paid to the manufacturer as a fertilizer subsidy. Urea is the largest volume fertilizer consumed in India and it comes under the subsidy regime.
Phosphate, complex and potash fertilizers have been partly decontrolled from pricing in 1992 and placed under a nutrient based subsidy (NBS) scheme since 2010. A fixed subsidy amount depending on its nutrient content (N, P, K, and S) is allowed for these products. It is revised by the Department of Fertilizers in the government from time to time and thus the government still has a say in fixing the prices of complex and potassic fertilizers.
Following the shift in the geopolitical situationi n Europe the cost of domestic production increased heavily and so also the subsidy burden on the government. To sustain production, the government absorbed all price rice and thus during 2022-23 the subsidy bill went as high as 2.51 trillion rupees.

Table 3: Fertilizer subsidies

Nutrient Efficiency
Even though per hectare consumption of fertilizer nutrients in India is much lower than compared to Japan, China, Egypt, Korea etc., the fertilizer use is still lower. Serious efforts were made to scientifically analyse the nutrient demand of the soil and administer the requisite quantum of nutrients to the crops. The government has issued soil health cards to farmers to promote integrated nutrient management for improving soil fertility and increase productivity.Farmers are advised to use a judicial mix of chemical, organic, bio fertilisers and other innovative fertilisers as recommended by the soil health card. Together with fertigation, drip irrigation, proactive soil nutrient and water management, the fertilizer use efficiency is being improved and wastage of valuable crop inputs is reduced to some extent.
Farmers are also encouraged to use coated, modified, and fortified fertilizer materials for better nutrient administration and to reduce pollution from leaching of nutrients to the environment. Thrust was also given to the use of secondary and micronutrients. Water soluble fertilizers (WSFs) are also produced and marketed by several producers. It dissolves completely in water and the nutrients are more efficiently absorbed by the plant through fertigation. Additional subsidy is provided under the NBS scheme for fertilizers fortified with boron and zinc.

Nano Urea and DAP
A major turning point in the Indian fertilizer sector is the development of Nano urea and DAP by agriculture scientists. These are nano technology products in liquid form which can be used as foliar spray for top-dressing instead of conventional soil based application of urea and DAP. The country’s major fertilizer producer in the cooperative sector IFFCO started industry scale manufacturing of the nano-products and that is made available to the farmers. Initial results indicate promising gains from the foliar application of nano-products to the crops and its long term implications are being studied.
Being an agrarian country India has a large reserve of biomass. Use of biomass for fertilizer application is being promoted in a big way. Composted municipal waste is also being used widely by Indian farmers. Of late, gasification of biomass to produce ammonia is also being explored by manufacturers.

Decarbonization of the Industry
The fertilizer Industry is both energy and carbon intensive. The carbon intensity has substantially reduced from the shift in the feedstock from coal and liquid petroleum components to natural gas. The Indian industry is highly optimized on the energy consumption front over the years incorporating the developments in unit operations, energy conservation, waste reduction, reactor revamp technologies, use of innovative equipment and catalysts and improving overall plant safety.
Most of the Indian plants are of vintage prior to 1995 except a few. A good number of retrofits and revamps have taken place in each of these plants as part of modernization, energy conservation and efforts to better safety and environmental aspects. In the present context of advancing decarbonisation, existing operators may have to adopt carbon capture sequestration and storage (CCSS) or other technologies to fall in line with the national agenda towards net zero emissions.
In the coming years, water electrolysis using rene-wable power to produce green hydrogen is slated to become the technology for ammonia synthesis. India’s National Green Hydrogen Mission (NGHM), National Solar Mission, National Bioenergy program, Ministry of Renewable Energy and Bureau of Energy Efficiency are partners in this pioneering program.
Already serious carbon reduction programs are being taken up by the world’s most renowned fertilizer producers across the globe and the Indian industry has also to fall in line with the above to ward off the adverse impacts of climate change.

Outlook for Future
Fertilizer is a strategic input to agriculture and therefore it is still one of the prime considerations of the government. The industry which was mostly a public sector activity in the 1980s is now dominated by the private sector due to change in the Government of India’s public policy towards state owned industries. The Government of India has made serious attempts to disinvest the public sector fertilizer units but so far not succeeded. Of late, the disinvestment of the public sector fertilizer units is not a priority item before the Government. Decarbonization of the industry to produce green fertilizers will certainly add on to the cost of production which can be overcome by diligent application based on the 4R concept (right source, right rate, right time, and right place) and by increasing nutrient efficiencies.
The Indian population now stands at 1430 million in 2023 and is growing at the rate of 0.92 % per annum. Around 68% of the people belong to a working age group and thus India is a young nation. The food demand is going to increase in the coming years and therefore a stable policy for sustainable agriculture duly supported by optimized production, effective delivery and utmost diligence in its use efficiency are important for the country.