Press Mud is a potential fuel of the future and sustainable Fertilizer.

The Indian sugar industry is like the Kalpvriksha as during its processing yields products and co-products which has significant values in the market. Over the year utilization pattern of these products has undergone significant change due to various reasons in and around the sugar industry. The prices of sugar can been traditionally decided by the Indian sugar policy and as of now its is FRP based system which effectively linked to sugar recovery via various means/products like sugar, sugar syrup, molasses B-heavy grade etc but not limited to. As per the Indian sugar policy's latest edition, the revenue from sugar and its co-products such as bagasse, Molasses, and Pressmud shall be shared with farmers. The Indian biofuel policy 2018?and its subsequent amendment/update enabled the Indian sugar industry to use its products and co-product in more productive ways than before. This collectively contributed to an increase in farmers' income in quite a significant way in the recent past.

Almost all the co-product from sugar mills are used quite innovatively which is somehow linked to the national interest of energy requirement at one end and the farmer's income enhancement at the other end. Sugar, Molasses and Bagasse added significant value to the Indian sugar industry over the years. Whereas another co-product which is slightly underutilized so far in content to extent of value other products added.

The pressmud which is commonly known as filter cake or press cake in the sugar industry. It is the residue of juice clarification process where the main product is clear juice and impurities settled at the bottom then filtered traditionally using a rotary vacuum filter. In a rotary vacuum filter, all the best possible efforts for the recovery of sugar are made and the final filtered residue is called filter cake or press cake. The typical generation of pressmud is about 3-5 to 4+% w/w of the cane crushing capacity of the mill. During this filtration process, bagasilo is added as a filter aid which is nothing but a fine bagasse particle making this method of filtration very popular in the sugar mill due to no additional expenses of filter aid. In the recent past, there are some mills that tried using centrifugal decanter for the separation of mud /cake from the juice clarification process but due to multiple reasons, it fail to impress the industry.

Press mud is basically mud i.e. dirt and a good amount of bagasilo and inorganic impurity courtesy of the clarification process in sugar mills. Way back when distilleries were only used for potable alcohol production majority of pressmud was distributed to farmers who used it as organic fertilizer in sugar cane fields. When Ethanol was projected as Biofuel and various schemes pushed to enhance the production of Ethanol then bio-composting using press mud as the prominent substrate gained a boost as a method of zero liquid discharge apart from another measure to ensure zero pollution from distilleries. Evacuation of bio-fertilizers was one the major challenge in this method of spent wash treatment which in most of cases became an expense to such industries rather than became value added co-product. It might have solved the sugar mill press mud evacuation issue but it just got shifted to distilleries. The multifold increase in sugar mill capacities changed the dynamics of the press mud utilization in recent past. As a result which was supposed to be one of the potential co-product confined to as intermediate which generally transferred from sugar mill to some way of utilization or treatment at either unsold value or notional value.

As govt of India drafted a biofuel policy in 2018 for both liquid and a gaseous fraction of green, clean and indigenous biofuel which will significantly contribute to countries' energy security. Compressed biogas was seen one of the major gaseous biofuel which will solve multiple national issues and convert them to opportunities. The government of India has launched the SATAT ( Sustainable alternative toward affordable transportation) program which will target setting up about 5000 Compressed Biogas plants which potentially suffices the natural gas requirement to a greater extent while solving the pollution issue of the country.

The SATAT program enabled Indian entrepreneurs to come up with innovative ways of extracting biogas from low-value raw materials and convert them to value added co-products like fuel and fertilizers. As mentioned in my previous article ( link- https://www.dhirubhai.net/pulse/feedstocks-compressed-natural-gas-production-bharat-kadu/) the best possible feedstock for biogas / Compressed biogas Gas (CBG) Production shall have the following attribute but not limited to.

1.??????Higher Window of availability

2.??????Ease of Access and assured supply

3.??????Minimal Transport and handling requirements

4.??????Decent Yield of product and by-product

5.??????Relatively Ease of conversion

6.??????Benefit to society and their involvement in the process

Looking at feedstock under consideration press mud became one the most popular choice of the project developers even though there is huge push for rice straw and other agri residue.

At present sugar industry encashed Pressmud whenever opportunity is there on an average value of 100-400 Rs/MT which is about 4 to 16 Rs/MT of cane crushed. IF this Pressmud is used in bio-composting with Pressmud then Pressmud contribution of fertilizer is appx. 200-250 kg per MT of press mud used and average Bio-Composting selling price is 700-1000 Rs/MT which results in appx value realization of about 140 to 400 Rs/MT excluding cost of production which is generally higher than the selling price as prime objective manufacturing such biofertilizers is compliance to Zero liquid discharge requirement of distillery effluent not the production of fertilizer. Further to this additional insite to evaluation of feedstock for CBG production can be referred at

In the recent past due to an exponential increase in coal prices, the cheaper alternative demand has gone up significantly. The Pressmud in some cases is sun-dried and converted to pellets which can substitute some of the high-cost fuel in short term resulting in demand for Pressmud for applications other than bio-composting.

One ton of average specification of press mud if converted to CBG then appx. 40 kg or CBG is produced along with about 110-130 kg of solid biofertilizers and 500-700 lit of liquid fertilizer. The Solid fertilizer market selling price is about 2.5 to 3.0 Rs/Kg and as per the latest CBG pricing & Retail selling prices of CNG one can expect min 65 Rs/kg for CBG as a safe bet. The Revenues from such conversion add up to about 3000 Rs/MT of Pressmud. The potential revenue from press mud to CBG could be about 120 Rs/MT of Cane crushing which is significantly higher than what we are getting as of now.

The better value utilization of Pressmud will definitely result in a significant increase in farmers’ income if the benefits are passed on to farmers to ensure a sustainable CBG manufacturing business which will result in a win-win for all the stockholders of the value chain.

Please note these are just estimated number which moving forward needs to be evaluated for a specific case which will largely cover the situation in most of the mills of India.

This will enable all sugar mills to become a true bio-refinery which will be the significant pillar of Indian food and energy security apart from connecting millions of farmers to building a nation which is self-sufficient and making India the Next Superpower.?