In a recent article published in the journal Results in Engineering, researchers led by Chaiya Klinsukon investigated a sustainable alternative to synthetic fertilizers by valorizing sugar industry waste into pelletized soil amendments. Their study aimed to address the widespread soil degradation and environmental pollution caused by over-relying on conventional farming practices. The team’s goal was to create a beneficial soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More from abundant, nutrient-rich sugar production by-products such as vinasse sludge, molasses wastewater, and bio-organic compost. Their findings present a promising, cost-effective solution that not only enhances crop growth but also promotes a circular economy in agriculture.

The research began with a critical first step: analyzing the raw materials from the Kaset Thai International Sugar Corporation in Thailand. The materials—vinasse sludge, molasses wastewater, sludge, bio-organic compost, and biogas effluent—were tested for their nutrient composition and heavy metal content. The analysis revealed significant variability, underscoring the importance of selecting the right combination of materials. Notably, all materials were found to have heavy metal concentrations well below the safety thresholds set by the Land Development Department of Thailand, making them safe for agricultural use. From these materials, the team developed six different formulations (F1-F6). These formulations were subjected to a 45-day aerobic fermentation process and monitored for temperature, pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, and electrical conductivity to ensure proper compost maturation.

Among the six formulations, F2—a combination of sludge, vinasse sludge, and molasses wastewater—emerged as the most effective. F2 stood out for its high levels of essential nutrients, including organic matter (43.06 mg kg−1), total nitrogen (2.07 mg kg−1), phosphorus (0.61 mg kg−1), and potassium (1.88 mg kg−1). This nutrient richness suggests a synergistic effect from combining different waste streams. F2 also had an ideal C/N ratio of 20.81, which is a key indicator of compost maturity and nutrient availability for plants.

The researchers then transformed the composted materials into pellets, which offers several practical advantages over traditional compost, including easier handling, storage, and application. During pelletization, F2 again proved superior, achieving the highest pellet formation percentage of 92.65% and the highest bulk density of 714.60 kg m−3. These physical properties make the pellets well-suited for mechanized agricultural systems. Additionally, the F2 pellets demonstrated excellent wettability, meaning they can absorb water effectively when applied to soil, a crucial feature for improving soil moisture retention.

To test the practical effects of these pellets, the team conducted greenhouse trials with chili plants ( Capsicum annuum L.) and maize seeds. The results were compelling. Chili plants treated with the F2 pellets showed remarkable growth, with a 31.2% increase in biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More and a 27.5% increase in shoot height compared to the control group. The maize seeds also responded well, with the F2 formulation yielding a germination index of 96%—the highest among all treatments. This growth enhancement is directly linked to the F2 pellets’ ability to improve soil properties, particularly by increasing its water-holding capacity and early availability of nutrients like nitrogen, phosphorus, and potassium. The soil texture in treated pots shifted from pure sand to loamy sand, a much more favorable condition for crop cultivation.

Beyond the agronomic benefits, the study also highlights the strong economic potential of this approach. The production cost of the F2 pellets was estimated at just 2.90 THB per kilogram (0.08USD/kg), which is significantly less than the retail price of commercial organic fertilizers in Thailand, which can be up to 12 THB per kilogram. This cost-effectiveness, combined with the proven benefits for soil health and crop yield, makes these pelletized amendments a compelling solution for farmers looking to reduce their reliance on expensive chemical inputs.

The study concludes that converting sugar industry waste into pelletized soil amendments is a viable and sustainable strategy for improving soil fertility and plant growth. While the research successfully demonstrated these benefits in a greenhouse, the authors recommend further research to explore long-term field performance, microbial interactions, and economic feasibility on a larger scale. This work provides a clear roadmap for creating value from waste, contributing to a more resilient and resource-efficient agricultural future.

Source: Klinsukon, C., Boonlue, S., Juntahum, S., & Laloon, K. (2025). Valorization of Sugar Industry Waste into Pelletized Soil Amendments for Enhanced Plant Growth and Soil Improvement. Results in Engineering, 28, 107068.