Tea Waste and its potential utilizations.

Tea waste. Tea waste potential. Tea waste e-auction or selling the tea waste. Tea Waste Products. Caffeine extraction from tea waste.

Tea waste is a lignocellulosic biomass consisting of cellulose, hemicellulose, lignin, polyphenols, proteins and tannins. Tea comprises of biologically active substances such as polyphenols (catechins, flavonoids, proanthocyanidins), methylxanthines, alkaloids (caffeine, theophylline, theobromine), vitamins, minerals, terpenoids, pigments, amino acids and polysaccharides hence a small amount of these elements are also expected in the waste.

Tea is a well known beverage. It’s estimated that daily consumption of tea is around 18-20 Billion cups. The global per capita consumption is estimated to be about 35 litres. India is the second largest tea producer next to china. India contributes about 27.4% of the total worldwide tea production with an area of about 5,79,000 hectares and an approximate annual production of 85,70,000 tonnes

In India, all the tea factories generate large quantities of tea wastes including the discarded leaves, buds and stems of tea. As per rule, clause 8 of the Tea Waste (Control) Order, 1959 the tea waste produced in India in 2020–2021 fiscal years would be around 25 million kilograms. In comparison to the huge quantities of waste generated, the number of buyers for tea waste is less in this country. Therefore, the potential and sustainable utilization of tea waste has become a matter of high research priority in the recent times.

The current article focuses on increasing awareness amongst the people regading utilization of tea waste for various commercial gains. As of now the known utilization of tea waste is as follows:

1.     Selling the Waste

    Well any registered buyer can buy the tea waste. The tea waste is bought or sold in marginal rates by the factories producing it. The waste once sold can be used in making Instant tea, in extraction of caffeine and other chemicals  as desired by the buyers and in accordance the  with law. It’s also known to be used in industries like cosmetics, pharmacy etc.

Tea waste can hereby be divided into two types, one is the factory tea waste and the other after the decaffeination called as decaffeinated tea waste.

2.     As a feed to animals

By separating the bioactive compounds Decaffeinated Tea Waste can be used as a feed to poultry and piggery. The waste when mixed with mustard cake is a good feed for the fishes. It’s also said to increase the immunity of the organisms and increase in egg laying capacity of the hens. However tannic acid content is higher (more than 5%) in the non decaffeinated or factory tea waste which on consumption can retard the growth and development of Broilers. The Decaffeinated tea waste contains 8 times less tannic acid as compared to non decaffeinated or factory tea waste.

Technology such as UV-Vis, Fluorescence Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Atomic Absorption Spectrometry (AAS) Atmospheric Pressure Chemical Ionization-Mass Spectrometry (LC/ APCI-MS). Etc are used in identification and of bioactive and toxic compounds in the tea waste. On the other hand separation of chemicals from the waste can be made by means of Low Pressure Liquid Column Chromatography (LPLC), Gas Chromatography (GC) and High Pressure Liquid Chromatography (HPLC).

3.     Tea waste can be used as a low cost adsorbent for the removal of Copper, Lead and ρ-nitro phenol from wastewater.

Activated tea waste can also be used as a potential low cost adsorbent for the removal of ρ-nitro phenol and is a good adsorbent for removal of Copper and lead from wastewater. In this case we can also include the plant parts of tea up to some extent (Where the plant parts from tea gardens has to be removed due to several reasons such as uprooting of the tea bushes). Tea wastes, like pruned branches, seed shells and tea residues, contain high content of lignin, cellulose, hemicellulose and other organic compounds, which are conducive to form a porous structure and large surface area during thermal conversion processes. Thus, the obtained bio char or activated carbon generally performs with excellent adsorption capacity.

4.     Re-processing of tea waste can be done for the production of bio ethanol and biopolymers. Ethanol is used along with petrol as an fuel.

5.     Tea waste could be used as an effective and economic substrate for oyster mushroom cultivation.

    Mushroom cultivation at this moment is a good source of part time for the farmers. Many agricultural wastes such as rice straw are utilized. The tea waste can also be utilized as an substrate for the production specially when the tea factories are located suitably for continuous supply.

6.     Bio-fertilizer from tea waste

    Factory Tea Waste can be mixed with cow dung and other organic matter and kept for 45 days. After addition of 5% urea to the mixture we can apply in the plantations. To be noted that Due to caffeine, tea waste increases the acidity of soil. Tea waste contains significant amounts of n-triacontanol which has plant growth promoting properties and might also positively impact different other physiological properties like the formation of leaf primordial and development of primary leaves.

The Image depicts the incense cones made from tea waste.

7.   An extensive experiment was carried out by us during the Experiential Learning Programme, 2022 Tea Processing Unit, Department of Tea Husbandry and technology at Assam Agricultural University for utilization of tea waste in developing various products. Incense cones were developed from the black tea waste. Tea waste can be used as an incense base material for making incense sticks, which is otherwise mostly procured from outside Assam. There are several other products being developed from both black and green tea waste in the university.

8. Tea wastes have a huge potential in making of many other products such as nicotine free cigarettes. The plant fiber can be used as a material for making cigarettes in place of tobacco which is less harmful then the tobacco.

Tea waste possesses outstanding potential towards the extraction of different value-added materials. Over the years, a significant number of research works explored the applications of tea waste in various industrial and environmental fields. However, the commercial and real-world utilization of tea waste is still very limited. On utilization up to its fullest potential the writers believe that Tea Waste can be a revolutionary waste of today which can be converted to a great resource. 

References

Potential and sustainable utilization of tea waste: A review on present status and future trends by Banhisikha Debnath, Dibyajyoti Haldar, Mihir Kumar Purkait .

Tea Waste Management: A Case Study from West Bengal, India Anurag Chowdhury, Satyajit Sarkar, Akash Chowdhury, Soumik Bardhan, Palash Mandal and Monoranjan Chowdhury.

Tea waste as a low cost adsorbent for the removal of Cu and Pb from wastewater B.M.W.P.K. Amarasinghe, R.A.Williams

Current understanding in conversion and application of tea waste biomass: A review Shasha Guo, Mukesh Kumar Awasthi, Yuefei Wang, Ping Xu 

Tea waste: an effective and economic substrate for oyster mushroom cultivationDoudou Yang, Jin Liang, Yunsheng Wang, Feng Sun, Hong Tao, QiangXu, Liang Zhang, Zhengzhu Zhang, Chi-Tang Ho, Xiaochun Wan