Nitrogen removal from wastewater using a double-biofilm reactor with a continuous-flow method

Area of Science:

• Environmental microbiology
• Wastewater treatment technologies
• Bioreactor design

Background:

• Nitrification and denitrification are key processes for removing nitrogen contaminants from wastewater.
• Simultaneous nitrification and denitrification can be challenging due to competing microbial requirements and inhibitory factors.
• Existing bioreactor designs may not fully optimize these processes concurrently.

Purpose of the Study:

• To develop and evaluate a novel double-biofilm reactor for simultaneous nitrification and denitrification.
• To investigate the effectiveness of a membrane-supplemented substrate system in enhancing treatment efficiency.
• To minimize inhibitory effects between nitrification and denitrification processes within a single reactor.

Main Methods:

• Cultivation of nitrification and denitrification microorganisms into two distinct biofilm modules: permeable support bioreactor (PSB) and membrane feeding substrate bioreactor (MFSB).
• Integration of PSB and MFSB into a single double-biofilm reactor.
• Supplementation of the membrane with substrates (oxygen and methanol) to control dissolved oxygen (D.O.) and chemical oxygen demand (COD) levels in the bulk solution.

Main Results:

• The double-biofilm reactor successfully treated nitrogen contaminants in wastewater.
• Low D.O. and COD levels in the bulk solution were maintained due to membrane substrate supplementation.
• High nitrification efficiency (96.5%) and denitrification efficiency (82%) were achieved simultaneously.

Conclusions:

• The developed double-biofilm reactor is effective for simultaneous nitrification and denitrification in wastewater treatment.
• The membrane-supplemented substrate system effectively minimized inhibitory effects, enhancing overall process efficiency.
• This approach offers a promising solution for advanced nitrogen removal from wastewater.