Composting of washed Ulva reticulata seaweed: process parameter variations and compost quality

Co–composting process of unwashed (Run A) and washed (Run B) seaweed Ulva reticulata with bagasse and broiler litter was studied. Peak temperatures of 48.9°C and 55.2°C were recorded for Runs A and B, respectively. For Run A, the starting wet bulk density was 43.31 kgm^–3 and increased by 5.2 times on day 23. Net biodegradable Volatile Solid (VS) reductions were 2.19 and 11.44% for Runs A and B, respectively. Beyond day 37, the respiration rate of both composts had decreased to 8.87 mg CO₂.C day^–1g^–1 VS and 8.09 mg CO₂.C day^–1g^–1 VS (Runs A and B, respectively). Washing treatment lowered the chloride content by 3–5 times in Run B. Final compost from Run B had a better fertilising capacity with its higher N, P and K contents.

Keywords: composting, washing treatment, compost quality, Ulva reticulata seaweed: process parameters, bagasse, broiler litter, chloride content, fertilising capacity