Australian Centre for Water
and Environmental Biotechnology

AWMC Seminar Program: Jia Meng and Angelica Guerrero Calderon

Title: Free nitrous acid pre-treatment enhances anaerobic digestion of waste activated sludge and rheological properties of digested sludge: a pilot-scale study

Presenter: Jia Meng

Abstract: The effects of FNA pre-treatment on the rheological properties of digested sludge were investigated at a pilot-scale, along with the improvement in VS destruction and biogas production. The results confirmed the enhancing effect of FNA pre-treatment on methane production by 37%, consistent with previous laboratory studies. Equally importantly, FNA pre-treatment substantially reduced the viscosity of TWAS by 50%. Similarly, these viscosity parameters of the digested sludge were also reduced by 78%, caused by both enhanced VS destruction and inherent changes of the digested sludge. The reduction in viscosity is important as it allows the digester to be operated at a higher solids concentration, thus further increasing the capacity of anaerobic digester. While the sludge dewaterability remained the same, the polymer requirement for dewatering was reduced by 24%.


Title: The Effect of Free Nitrous Acid and Free Ammonia Pre-Treatment on Energy Recovery for Luggage Point - MERINO and AQIP Pilot Wastewater Treatment Processes
Presenter: Angelica Guerrero Calderon

Abstract: Sludge pre-treatments with free nitrous acid (FNA) and free ammonia (FA) have shown the capability to enhance methane production and digestibility of secondary sludge during anaerobic digestion. The FNA and FA are renewable and low-cost chemicals able to be produced on site. FNA can be obtained through the side-stream nitritation of the anaerobic digestion liquor, while FA could be generated directly from the conventional anaerobic digestion liquor.  FNA and FA pre-treatment laboratory experiments were conducted as batch test using sludges from primary, secondary, Maximizing Energy Recovery through Innovative Nitrogen Removal (MERINO) and the Advance Queensland Innovation Project (AQIP) wastewater treatment processes. 

This study, for the first time, demonstrated that the pre-treatments are also effective for MERINO and AQIP sludges. Comparing the control experiments with the pre-treated sludges, it was exhibited at least 40 ± 5 % increasing of methane production during anaerobic digestion. This suggests that the sludge pre-treatment with FNA and FA are effective to promote energy recovery on innovative wastewater treatment processes.

Based on the results, FNA and FA pre-treatments are promising technologies to significantly enhance the energy recovery on innovative wastewater treatment processes, to be environmentally sustainable and to set a good example of circular economy.

Event Details
Date & Time: 
Friday, 24 May 2019
9am - 10am
Venue: AIBN Building 75, Level 1 Seminar Room

Event Contact: