This research was conducted to study the assessment and utilization of synthetic soil aggregates developed by using coal fly ash, paper waste with starch waste as an alternative waste utilization method in Okinawa,Japan. Development of synthetic soil aggregates with different wastes can be regarded as an eccentric way of waste utilization, which is being not much addressed. Synthetic soil aggregates showed low bulk density, high aggregate strength, high hydraulic conductivity, high water holding capacity, high carbon content and alkaline pH. Experimental results revealed that larger proportion of synthetic soil aggregates had particle size diameters between 3 mm and 6 mm. Furthermore, scanning electron microscopic observations of the synthetic soil aggregates showed well enmeshed coal ash particles in the fibrous paper waste matrix creating porous spaces within the aggregate. Buried synthetic aggregate samples in the soil showed low decomposition rates with the time. It is evident that 25% (w/w) of synthetic soil aggregate incorporation as a soil amendment to the low productive acidic “Kunigami Mahji” soil in Okinawa, Japan was the best mixing percentage, which significantly enhanced the growth and yield parameters of Japanese Mustard Spinach compared to the original soil. Integration of synthetic soil aggregates as a soil amendment significantly improved the water holding capacity, porosity, hydraulic conductivity, carbon content, pH, and cation exchange capacity of the original “Kunigami Mahji” soil. Furthermore, experimental results revealed that a mixture of synthetic soil aggregates and oil palm waste at the ratio of 1:10 (v/v) can be successfully utilized as a potting media for the cultivation of ornamental plants such as French marigold and Cosmos.

Key words: Coal fly ash, oil palm waste, paper waste, potting media, synthetic soil aggregates, waste management