Browsing by Author "Udayanga, W.D. Chanaka"

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Possibility of ceylon tea waste conversion to biochar –a short review
(The Library, University of Kelaniya, Sri Lanka, 2023) Perara, S.A.T. Himaya; Udayanga, W.D. Chanaka
A few countries fulfil global tea demand, and Sri Lanka, formerly known as Ceylon, is one of the top tea exporters. Tea is Sri Lanka's largest agricultural export, with an annual production of approximately 340 million kg. Consequently, the tea industry generates significant quantities of tea waste. Unfortunately, the Sri Lankan tea industry often ignores proper tea waste management, relying on open dumping and burning, which can harm the environment despite the biodegradable nature of the waste. Among a number of modern waste management methods, pyrolysis is gaining increasing attention as a sustainable waste treatment method as it transforms waste into carbonaceous materials, biofuel and syngas, leaving no waste behind at comparatively lower temperatures (400-600℃). Considering the nature of the Ceylon tea industry, which mainly uses conventional tea production processes, this short review article mainly focused on the effect of tea pyrolysis temperature, derived biochar activation methods, and their uses. Biochar derived from tea waste has demonstrated remarkable utility in various fields. By converting waste into stable carbonaceous materials, it not only mitigates local emissions but also serves as a reliable long-term carbon storage. Moreover, biochar and activated carbon derived from tea waste has proven efficient and cost-effective for removing water, soil, and air contaminants. Industry can obtain financial benefits by introducing derived activated carbon as an adsorbent. These facts highlight the suitability of adopting low-temperature pyrolysis of tea waste and biochar production to the Ceylon tea industry using simple techniques such as double-barrel systems that can be operated with the excess heat produced in boilers.
Prospects of recycling used plaster of paris – short review
(The Library, University of Kelaniya, Sri Lanka, 2023) Dunuwila, D.H.W.H.M.M.S.; Udayanga, W.D. Chanaka
Plaster of Paris (POP- CaSO4. 0.5H2O) is used for various applications, such as in the ceramic industry, where it serves as a crucial component in crafting moulds and cementitious materials used in construction projects such as wall plaster, wall boards, and gypsum blocks. The dental industry uses POP for mounting casts or models of oral tissues. POP is commonly used in orthopaedic applications to support fractures for broken bones, making positive casts/models for fabricating mobility assistive devices. Demand for POP is continuously increasing with the expansion of the mentioned industries. Notwithstanding this sizable market, POP disposal has become a serious concern. Conventional POP disposal techniques, such as burning and dumping in landfills, negatively impact the environment by causing groundwater contamination, air pollution, disturbance of habitats, and land use issues. In this regard, this review focuses on the possible recyclability of POP. POP recycling is typically done by calcining used POP at relatively higher temperatures (150-1800C), where dehydration of used POP (CaSO4.2H2O) becomes recycled POP (CaSO4.0.5H2O). Many other factors, such as temperature and curing time, particle size, sample size, POP-to-water ratio, method of recycling, and secondary additives, affect the quality of recycled POP. Recycling reduces the need for virgin materials, conserves natural resources, and minimizes the environmental impact of extraction and production, encouraging the circular economy.