Embedding constructed wetland in sequencing batch reactor for enhancing nutrients removal: A comparative evaluation

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Bioreactor Design

Background:

• Conventional activated sludge (CAS) systems face challenges in efficient nutrient removal and aesthetic appeal.
• Integrating constructed wetlands (CW) offers potential for enhanced biological treatment and environmental benefits.
• Developing sustainable and cost-effective solutions for upgrading existing wastewater treatment infrastructure is crucial.

Purpose of the Study:

• To propose and investigate a novel green bio-sorption reactor (GBR) by embedding CW into CAS.
• To evaluate the GBR's performance in treating piggery wastewater, focusing on BOD, TP, and TN removal.
• To compare the GBR with other advanced reactor systems like MBBR and IFAS.

Main Methods:

• A pilot-scale GBR was designed by incorporating wetland substrate carriers (dewatered alum sludge) into a sequencing batch reactor (SBR) system.
• The GBR was operated for three months using diluted piggery wastewater.
• Performance metrics including BOD, TP, and TN removal efficiencies were monitored and compared with MBBR and IFAS.

Main Results:

• The GBR achieved average removal efficiencies of 96% for BOD, 99% for TP, and 90% for TN.
• The system demonstrated superior purification performance compared to MBBR and IFAS.
• The use of dewatered alum sludge as carriers aligns with circular economy principles ('recycle, reuse, reduce').

Conclusions:

• The novel GBR system offers a sustainable and economical solution for retrofitting aging CAS plants.
• GBR enhances wastewater purification, provides aesthetic value, and has potential as a carbon sink.
• The integration of CW principles into activated sludge systems represents a promising advancement in wastewater treatment.