Improving municipal solid waste co-composting performance using activated biochar, leonardite, and MgSO₄-modified...

Area of Science:

• Environmental Science
• Soil Science
• Waste Management

Background:

• Municipal solid waste (MSW) co-composting requires effective amendments to improve compost quality.
• Biochar, zeolite, and leonardite are potential additives for waste stabilization and nutrient enrichment.

Purpose of the Study:

• To evaluate the impact of H2SO4-activated biochar (H2SO4-AB), NaOH-activated biochar (NaOH-AB), MgSO4-modified zeolite, and leonardite on MSW co-composting.
• To determine the effects of these additives on compost maturity, stability, and quality parameters.

Main Methods:

• Co-composting of MSW with various additives: H2SO4-activated biochar, NaOH-activated biochar, MgSO4-modified zeolite, and leonardite.
• Monitoring of key maturity and stability parameters throughout the co-composting period.
• Analysis of microbial respiration, dehydrogenase activity, humification, nutrient content, and heavy metal concentrations.

Main Results:

• NaOH-AB and H2SO4-AB modified biochar surfaces, enhancing microbial activity and respiration rates by an average of 24% compared to control.
• Leonardite amendment led to higher humification, while 5% NaOH-AB compost showed the longest thermophilic phase (7 days), highest temperature (71.5°C), germination index (130.9%), and total nitrogen (1.37%).
• 10% H2SO4-AB compost exhibited maximum organic matter (36.8%), C/N ratio (18.1), lowest nitrate, and reduced heavy metal availability (Zn, Fe, Mn, Pb).

Conclusions:

• Acid and base-activated biochars are effective additives for improving MSW co-compost quality.
• NaOH-AB and H2SO4-AB treatments offer distinct advantages in terms of maturity, nutrient content, organic matter, and pollutant reduction.
• These activated biochars represent promising solutions for sustainable MSW management and compost production.