Optimizing Bioaugmentation for Pharmaceutical Stabilization of Sewage Sludge: A Study on Short-Term Composting Under...

Area of Science:

• Environmental Science
• Microbiology
• Soil Science

Background:

• Composted sewage sludge can contain pharmaceuticals, posing risks as soil amendments due to incomplete removal and toxicity.
• Previous bioaugmentation-composting methods were effective but unprofitable due to long inoculant acclimatization periods.

Purpose of the Study:

• To develop a shorter, profitable bioaugmentation-composting process for sewage sludge using a native microbial consortium and Penicillium oxalicum XD 3.1.
• To evaluate the stability, microbial diversity, pharmaceutical degradation, and toxicity reduction of the enhanced composting process.

Main Methods:

• Simultaneous inoculation of sewage sludge and olive pruning piles with a native microbial consortium and P. oxalicum XD 3.1.
• Frequent windrow turning and monitoring of physicochemical and biological parameters.
• Assessment of bioaugmentation stability, pharmaceutical degradation rates, and toxicity (microtoxicity and phytotoxicity).

Main Results:

• Both bioaugmentation treatments reached adequate composting conditions 100 days earlier than previous methods.
• Treatments maintained native microbial populations and enhanced microbial diversity.
• Achieved 70-72% pharmaceutical removal; only P. oxalicum inoculation yielded favorable toxicity results for soil amendment.

Conclusions:

• A shorter, stable, and effective bioaugmentation-composting process using P. oxalicum was developed.
• This method reduces pharmaceuticals and toxicity in composted sewage sludge, making it suitable for soil application.
• P. oxalicum inoculation is a promising strategy for improving the safety of sewage sludge-derived compost.