Pretreatment of herbal waste using sonication

Area of Science:

• Environmental Engineering
• Wastewater Treatment
• Biotechnology

Background:

• Municipal wastewater often contains herbal waste, posing treatment challenges.
• Mechanical pre-treatment alone may not sufficiently enhance waste biodegradability.
• Hydrodynamic cavitation (HC) is an emerging technology for waste treatment.

Purpose of the Study:

• To investigate the effect of hydrodynamic cavitation on herbal waste biodegradability.
• To assess the impact of HC on the chemical and morphological structure of herbal waste.
• To determine if HC generates by-products detrimental to subsequent biological treatment.

Main Methods:

• Herbal waste in municipal wastewater underwent mechanical pre-treatment followed by hydrodynamic cavitation.
• HC parameters: 3.5 bar inlet pressure, 0.11 cavitation number, 30.5 recirculation passes.
• Analyses included BOD5/COD ratio, fiber component analysis, FT-IR/ATR, TGA, and SEM.

Main Results:

• The BOD5/COD ratio increased by over 70% within 5-10 minutes, indicating rapid enhancement of biodegradability.
• Hydrodynamic cavitation altered herbal waste composition, reducing hemicellulose, cellulose, and lignin content.
• Structural and morphological changes were confirmed via FT-IR/ATR, TGA, and SEM analyses.

Conclusions:

• Hydrodynamic cavitation effectively enhances the biodegradability of mechanically pre-treated herbal waste.
• HC treatment modifies the herbal waste structure without producing inhibitory by-products.
• This suggests HC is a promising pre-treatment method for improving wastewater biological treatment efficiency.