Research and projects

This research project was conducted at the University of Sri Jayewardenepura as part of a broader effort to develop sustainable, eco-friendly solutions for marine oil spill remediation. With recent maritime disasters near Sri Lanka, including the MT New Diamond and X-Press Pearl incidents, the ecological and socio-economic impacts of petroleum hydrocarbon (PHC) contamination have become increasingly severe. Conventional oil spill cleanup methods face limitations such as toxicity, high cost, and low efficiency. This study focuses on utilizing dendro biochar, a by-product of Sri Lanka’s dendro power industry, as a low-cost, biodegradable, and effective sorbent. By enhancing dendro biochar with graphite or graphene, the project aims to create a composite material with improved oil sorption capacity, offering a promising green technology for oil spill remediation in both marine and freshwater environments.

Objectives

To develop and optimize dendro biochar-based sorbents for efficient oil spill remediation under laboratory and pilot-scale conditions.

Specific Objectives:

1. To characterize the physicochemical properties of dendro biochar obtained from different dendro power plants in Sri Lanka.

2. To enhance biochar performance by developing composites with graphite and evaluate their structural and functional characteristics.

3. To assess the oil sorption capacity of biochar and its composites in seawater and freshwater under varying conditions (pH, oil type, and dosage).

4. To perform pilot-scale experiments to simulate real-world oil spill conditions and test the effectiveness of the developed sorbents.

Publications

Pallewatta, S., Samarasekara, S. M., Rajapaksha, A. U., & Vithanage, M. (2023). Oil Spill Remediation Using Biochar Derived from Bioenergy Industries: A Pilot-Scale Approach during the X-Press Pearl Maritime Disaster. Marine Pollution Bulletin, 189, 114813. https://doi.org/10.1016/j.marpolbul.2023.114813

Pallewatta, S., Rajapaksha, A. U., Samarasekara, S. M., & Vithanage, M. (2022). Removal of spilled engine oil using dendro biochar as an adsorbent. International Research Conference of the SLTC Research University, Sri Lanka.

Pallewatta, S., Rajapaksha, A. U., Samarasekara, S. M., & Vithanage, M. (2023). Adsorptive removal of oil spills by waste-derived dendro biochar: A green-oriented approach. 11th YSF Symposium. 

This final year research project for the BSc (Hons) degree was conducted at the Tea Research Institute, Thalawakelle, Sri Lanka. The study focused on improving the detection of total polyphenol content in fresh tea leaves, a critical quality trait in tea breeding programs. Traditional chemical methods used for polyphenol quantification are time-consuming, expensive, and destructive, limiting their application for large-scale sample screening. To overcome these challenges, this study explored the use of Near-Infrared Spectroscopy (NIRS) as a rapid, non-destructive, and in-vivo method for predicting total polyphenol content in fresh tea leaves.

Objectives

Developing near-infrared spectroscopic methods for the in-vivo detection of polyphenol content in fresh tea leaves is a promising endeavor with potential applications in the tea industry.

Results

Ten tea cultivars with varying levels of total polyphenol content were assessed using a direct probe FQA-NIR Gun (600–1100 nm). Spectral data were collected from the first and second leaves (excluding the bud). SIMCA (Soft Independent Modeling of Class Analogy) was used for qualitative classification, and Partial Least Squares (PLS) regression was used for quantitative prediction. Principal Component Analysis (PCA) was applied to remove outliers and improve model accuracy. The SIMCA model developed using the 1st derivative and Pareto scaling showed high classification accuracy with prediction rates of 95.5% for high-TPP, 98.3% for mid-TPP, and 96.6% for low-TPP cultivars. The wavelengths 703 nm, 669 nm, and 987 nm were identified as the most informative for total polyphenol prediction. These findings confirm the potential of NIRS as a reliable and efficient tool for non-destructive tea quality assessment.

Publications

Pallewatta, S., Balasooriya, J., & Ranatunga, M. (2021). Non-destructive estimation of total polyphenol content in fresh tea (Camellia sinensis) leaves by near-infrared spectroscopy. Undergraduate Research Symposium on Agricultural Engineering & Environmental Technology, University of Ruhuna.

Water hyacinth (Eichhornia crassipes) is a major invasive species in Sri Lankan water bodies, causing significant degradation of water quality, biodiversity loss, and reduction in aesthetic value. However, due to its ability to rapidly absorb nutrients like nitrogen and phosphorus, it holds great potential for compost production. Composting water hyacinth can offer a sustainable solution to control its spread while producing a valuable soil amendment. Nonetheless, its high moisture content and risk of heavy metal accumulation require proper composting practices and material combinations.

Objectives

1. To prepare compost using water hyacinth combined with different organic materials

2. To evaluate the quality and safety of the produced compost mixtures

3. To assess the effect of different water hyacinth compost mixtures on the growth performance of Capsicum annum (Chilli), variety MI-2

Results

The composting process reached maturity within 12 to 14 weeks across all treatments, with C:N ratios maintained between 15:1 and 20:1 and heavy metal concentrations within the permissible limits for safe agricultural use. Among the mixtures, the compost containing water hyacinth, coir dust, cow dung, and dry leaf litter (MS) demonstrated the highest compost quality, showing the greatest organic matter content, total nitrogen, and available potassium. In the greenhouse experiment with Capsicum annum (chilli), the compost mixture with 50% water hyacinth, 25% dry leaf litter, 5% Eppawala rock phosphate, 5% wood ash, and 15% spent poultry litter significantly enhanced plant growth. This treatment recorded the highest shoot length and shoot dry weight, indicating that water hyacinth-based compost, when enriched with suitable additives, can be an effective organic fertilizer to support healthy crop development.

Publications

Amarasinghe, S. R., Pallewatta, P. G. S., & Samarakoon, S. A. M. E. (2021). Effect of Water Hyacinth (Eichhornia crassipes) compost mixtures on growth attribute of Chilli (Capsicum annuum). University of Ruhuna.

Amarasinghe, S. R., Samarakoon, S. A. M. E., & Pallewatta, S. (2019). Production of compost by means of eradicating invasive Water Hyacinth (Eichhornia crassipes). 14th International Conference of the East and Southeast Asia Federation of Soil Science Societies (ESAFS), Taipei, Taiwan.