Solid waste generation and decomposition using compost bin technique in Pulau Pinang, Malaysia

Area of Science:

• Environmental Science
• Soil Science
• Waste Management

Background:

• Improper solid waste disposal presents significant environmental challenges.
• Composting offers a sustainable solution for managing organic waste, such as grass clippings.
• Local adaptation of composting technology is crucial for effective waste management in specific regions.

Purpose of the Study:

• To evaluate the efficacy of a locally-made compost bin for decomposing grass clippings.
• To analyze the physicochemical properties of the compost produced.
• To assess the potential of the compost as an organic fertilizer and soil conditioner.

Main Methods:

• Grass clippings were decomposed in a locally-made compost bin over 77 days.
• Key parameters including bulk density, pH, moisture content, nutrient levels (N, P, K), and heavy metal concentrations (Fe, Zn, Cu) were measured.
• The carbon/nitrogen (C/N) ratio and germination index were determined for the final compost.

Main Results:

• A 34% reduction in compost bin volume was achieved.
• Bulk density decreased from 732 to 482 kg m⁻³, and pH shifted favorably.
• The final compost exhibited a moisture content of 44.06%, a C/N ratio of 14:1, and contained essential nutrients and heavy metals within acceptable limits.
• The compost achieved over 75% germination index for bean sprouts within 72 hours, indicating its quality as a fertilizer.

Conclusions:

• The locally-made compost bin effectively decomposed grass clippings, yielding a valuable organic fertilizer.
• The resulting compost is suitable for use as a soil conditioner, enhancing soil properties and promoting plant growth.
• Further improvements in compost bin design are recommended to mitigate greenhouse gas emissions.