High rate composting of herbal pharmaceutical industry solid waste

Area of Science:

• Environmental Science
• Waste Management
• Agricultural Science

Background:

• Herbal wastes are challenging to degrade, posing disposal issues.
• Composting is a sustainable method for managing organic waste.
• Rotary drum composting offers potential for high-rate processing of difficult materials.

Purpose of the Study:

• To investigate high-rate composting of recalcitrant herbal wastes.
• To evaluate the impact of different rotary drum operational parameters.
• To assess compost quality using various analytical methods.

Main Methods:

• Four trials were conducted in a 3.5 m(3) rotary drum composter.
• Trials varied in turning frequency (1-2 turns/day), use of inocula, and waste mixtures (herbal waste, cattle manure, vegetable market waste).
• Compost quality was assessed via temperature, moisture, nitrogen content, Solvita maturity index, and Fourier-transform infrared (FT-IR) spectroscopy.

Main Results:

• One turn per day (trial 1) provided the most favorable composting conditions.
• Co-composting herbal and vegetable waste (trial 4) resulted in superior compost quality.
• FT-IR analysis indicated better stability and maturity in trials 1 and 4, with more intense aromatic and less intense aliphatic peaks.

Conclusions:

• Optimized rotary drum operation (1 turn/day) facilitates efficient composting of herbal waste.
• Co-composting enhances compost quality, improving stability and maturity.
• Rotary drum composting is a viable method for managing challenging organic waste streams.