What is Bagasse?
Bagasse is another by-product of the sugar production process. It is a dry and pulpy residue left behind when sugarcane stalks are crushed. There is a similar material called ‘agave bagasse’ made from the agave plant. Bagasse is principally used in the manufacturing process of paper, pulp and building materials as well as a biofuel for the production of energy, heat and electricity.
History and Origins
The word ‘bagasse’ originates from the French word ‘bagage’ meaning rubbish or waste. Bagasse was first used to describe debris from the pressing of olives, palm nuts and grapes however it soon came to refer to the residue of other processed plant materials. The term ‘bagasse’ nowadays is exclusively limited to the residue of sugarcane.
One of bagasse’s primary uses is in the paper industry. The method of using bagasse for paper production was invented by Clarence Birdsong in a small laboratory in ‘Hacienda Paramonga’, a sugar mill in Peru. With this promising discovery at hand, the company bought an old paper mill in New Jersey and shipped bagasse there from Peru in order to test the method’s reliability on an industrial scale. The method developed in 1937 and the first paper manufacturing machines were designed in 1938 in Germany.
It wasn’t until 1950 that the first successful commercial production of newsprint produced from bagasse was demonstrated by the ‘Noble & Wood Machine Company’. The demonstration took place before 100 industrial representatives and officials from 15 different countries. The demonstration proved to be extremely successful. This was mainly due to the economic importance of paper in countries which did not have easy access to wood fibres on account of their respective climates. In 2015, the Paramonga sugar mill, which first developed the bagasse paper process, produced 90,000 metric tonnes of paper!
Production, Storage and Properties
With bagasse being a by-product of sugarcane, the production quantity of bagasse in each country is in line with the quantity of sugarcane produced. The typical ratio is 3 tonnes of wet bagasse for every 10 tonnes of sugarcane crushed. This also means that the biggest producers of bagasse are Brazil and India as they are the largest sugarcane growing regions.
Once bagasse fibres are gathered from residual sugarcane, they are stored wet in order to remove any residual sugar which may impede further production. The bagasse is then blended with water until the compounds finally develop into a pulp which can then be further processed.
Bagasse is stored in different ways depending on its end use. In general, it is stored ahead of further processing. In electricity production for example, bagasse has to be kept in moist conditions with a mild exothermic process that results in drying the fibres gradually over time. In paper and pulp production however, bagasse has to be kept wet in order to aid the removal of ‘pith’ fibres. Pith fibres make up around 30-40% of bagasse and are derived from the core of the sugarcane plants, the properties of which hinder paper production.
Typically, dried bagasse is chemically made up of:
- 45-55% Cellulose
- 20-25% Hemicellulose
- 18-24% Lignin
- 1-4% Ash
- <1% Waxes
As previously mentioned, bagasse is used as a substitute for wood in many tropical and subtropical countries for the production of paper such as India, Argentina and Colombia.
Bagasse produces a pulp which possesses the physical properties well suited for printing paper, newspaper, cardboard, plywood, particle board, xanita board even furniture and biodegradable plastics. It can also be employed in the production of ‘furfural’, a clear colourless liquid which is used in the synthesis of chemical products like nylon and solvent.
Bagasse is often used as a fuel source for sugar mills themselves. When bagasse is burned in large quantities, it provides enough heat energy to satisfy, if not exceed, the energy needs of a typical sugar mill. It can also be used as a secondary fuel in a process called ‘cogeneration’. In cogeneration, bagasse can be used to provide electricity, and this can be sold to the consumer electrical grid.
There is a lot of research going into using bagasse as a biofuel in renewable power generation. It has potential to become an environmentally friendly alternative to corn as source of the biofuel ethanol. As bagasse is rich in cellulose, it may be able to produce commercial quantities of cellulosic ethanol. Research backs up the viability of bagasse in ethanol production however, the compatibility with conventional engines still requires investigation. As bagasse has a high moisture content, being typically between 40-50 percent, there may be multiple other complications in using it as a fuel. Bagasse is also used for manufacturing animal feeds by mixing it with molasses and enzymes. The ‘K-Much’ industry has patented a method of converting bagasse into cattle feed and this is marketed in a range of countries such as Thailand, Japan, Korea and Australia.
As mentioned previously in the sugar series in our sugarcane article, sugarcane is an extremely fast and renewable resource. Bagasse, as a sugar production by-product, is also sustainable. Whilst the research into bagasse being used for biofuel production is still underway, it nevertheless does not require any trees to be cut down thus not impacting the area of forests nor any additional cultivation areas. Bagasse is therefore a sustainable and environmentally friendly alternative to conventional paper production which uses wood and wastes much less energy in its production as well.
Bagasse plastic and hardware products are also completely biodegradable and compostable and can break down in as little as four weeks under the right conditions. Many restaurants, in attempting to be more sustainable, have replaced their plastic and Styrofoam containers and packaging with bagasse products and even some of their tableware too. In fact, bagasse is taking the takeaway industry by storm as obviously they have a high demand for one-use containers. Bagasse allows these industries to partake in sustainable practise with excellent alternatives to takeaway plates, bowls and paper napkins. Bagasse is clearly not only an effective sustainable source, but also a credible one.
So as you can see, when answering the question, what is sugar, you can see that sugarcane bagasse is anything but waste.
Images: Christa Dodoo, Will Kirk, Josh Withers, Arteum Ro