Biological nutrient removal enhancement using fermented primary and rotating belt filter biosolids

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Bioreactor Performance

Background:

• Biological nutrient removal (BNR) is crucial for wastewater treatment.
• Sludge fermentation liquid (SFL) can serve as a carbon source to enhance BNR.
• Primary clarification and rotating belt filtration (RBF) are primary treatment options impacting sludge characteristics.

Purpose of the Study:

• To compare the impact of primary clarification and RBF on BNR using SFL.
• To evaluate the effectiveness of SFL as a carbon source for nutrient removal and biogas production.
• To assess the economic implications of integrating sludge fermentation with primary treatment.

Main Methods:

• Comparison of primary clarification and RBF for SFL production.
• Addition of SFL to BNR reactors to assess nutrient removal efficiencies.
• Kinetics studies for denitrification and phosphorus release.
• Plant-wide modeling to evaluate biogas production and economic benefits.

Main Results:

• Both primary and RBF SFL comparably enhanced BNR, with removal efficiencies reaching 57% (TN) and 92% (TP).
• SFL addition significantly increased readily biodegradable COD and VFAs, enhancing nutrient removal despite increased nutrient loads.
• Plant-wide modeling indicated a 59% average increase in biogas production and potential for significant daily revenue generation from VFA production.

Conclusions:

• SFL from both primary and RBF sludges effectively enhances BNR processes.
• Integrating sludge fermentation with primary treatment offers substantial economic benefits through VFA generation and improved biogas production.
• Primary clarification followed by sludge fermentation presents a promising strategy for optimizing wastewater treatment efficiency and resource recovery.