Status of comprehensive utilization of tea residues
Tea contains a lot of nutrients, while traditional tea beverages and tea deep-processed products only use the water-soluble components in tea leaves, and there are still more nutrients remaining in the discarded tea residues. According to research reports, 17%-19% crude protein, 16%-18% crude fiber, 1%-2% tea polyphenols, 0.1%-0-3% caffeine still remain in the tea residue after extraction. , 1.5% to 2.0% of lysine, 0.5% to 0.7% of methionine, etc., which have high potential utilization value.
At present, the treatment of tea residues mainly focuses on tea residue fertilizer, tea residue feed, and extraction of effective functional components from tea residues. In addition, tea residues can also be used as dietary fiber, making pillow cores, and treating wastewater.
Tea Residue is Used as Fertilizer
Tea residues contain a large amount of organic carbon and nitrogen sources, with a carbon-nitrogen ratio of 6.76, which satisfies the relationship between the carbon-nitrogen ratio of plant residues and the release of mineral nitrogen: C/N<20, which can net release mineral nitrogen. Sri Lankan scientists reported in 1998 that the use of tea residues in tea gardens can improve the quality of tea leaves; Hu Minqiang and others developed tea residue bio-fertilizers using Trichoderma fermented metabolites. Chemical fertilizers have long-lasting fertilizer effects and obvious yield-increasing effects; the Department of Tea Science of Zhejiang University has successfully developed organic-inorganic compound fertilizers after microbial fermentation of tea residues and adding appropriate amounts of N, P, and K elements. This fertilizer has application prospects in current greenhouse cultivation. widely. Using tea residues as raw materials to form organic fertilizers through composting, and then adding other auxiliary elements, not only can form a compound fertilizer with low price and good fertilizer efficiency, but also can digest all the waste tea residues, so that the remaining nutrients return to the soil, reducing tea Slag environmental pollution.
Tea Residues are Used as Feed
Tea residues contain nutrients such as crude protein, amino acids, vitamins, and antioxidants such as tea polyphenols, which can effectively supplement the needs of poultry for nutrients. According to current research reports, tea residues can be directly added as feed or used as feed after microbial solid fermentation. Shu Qingling et al. raised broiler chickens after saccharification treatment of tea residues. After 30 days of captivity, the weight increased by 8% compared with control chickens, and the effect was obvious. Liu Shu et al. used tea residue as the main raw material (content reached 70%), and added other auxiliary materials appropriately. After co-fermentation with mixed bacteria, the crude protein content in the material reached 26% to 29%, which was 20% to 30% higher than the control. When the crude protein content in the piglet compound feed is reached, it can be directly used as feed to feed livestock and poultry, which can be described as turning waste into treasure. Using tea residue as raw material to directly process it into feed can improve the meat quality of poultry, and can also relatively reduce the cost of feed, and the nutritional value of feed after microbial fermentation is improved, which is more conducive to improving the meat quality of poultry.
The tea residue biomass pellet fuel uses the tea residue after tea extraction and the sludge in the wastewater treatment as raw materials, and is filtered by a plate and frame filter press, and then the tea residue after the pressure filter is put into a Rotary Dryer for drying. Finally, the pressed-dried sludge and the dried tea residue are mixed and extruded through a Ring Die Pellet Mill. The biomass pellet fuel can be used as fuel for biomass water heater and biomass hot blast stove. Through the development of tea residue Pellet biomass fuel, the waste tea residue can be completely digested and used as a new type of energy, which can effectively solve the environmental pressure caused by a large number of tea residues, improve the utilization rate of resources and reduce production costs while protecting the biomass environment. Improving the product yield is in line with the sustainable development needs of the ecological environment, and is more conducive to improving the added value of t ea production.
The key technology of using tea residue to develop biomass pellet fuel lies in the setting and optimization of technical parameters of plate and frame filter press, tumble dryer, Ring Die Pellet Machine, and optimization of the mixing ratio of tea residue and sludge.