Tertiary treatment of municipal wastewater at low temperature: comparing biocatalyst and nitrifying sand filters: PRESENTATION ONLY
Bobbio, J.1, Martin, B. 1, Germain-Cripps, E1. and Nair, A.2, 1Thames Water Utilities, UK, 2Microvi Biotech Inc., USA
(free)
Sustaining and enhancing pollutant removal is a priority for municipal sewage treatment works (STW) in light of ever stricter nutrients discharge consents. Low temperatures (<13ºC) have been widely reported to decrease the performance of biological nutrient removal processes, often driving the need for longer retention times, tertiary treatment and innovative technologies to maintain effluent quality at low temperatures.
In Microvi biocatalysts, organisms are retained within specifically engineered polymer structures, which promote a higher density of targeted organisms, help protect them from harsh environmental conditions such as toxicity and render the technology more robust to seasonal variations. A tertiary nitrification pilot plant was installed this summer on a rural STW (<10,000 population equivalent) in parallel to the current tertiary treatment (nitrifying sand filters, NSFs) to trial the Aerovi™ biocatalysts developed by Microvi. This study aims to investigate the biocatalyst ammonia removal capability at various operating conditions and compare its performance to the current NSFs, with an emphasis on the effect of low temperatures.
Results so far show that at higher temperatures (16ºC on average), the biocatalysts achieved a higher ammoniacal nitrogen removal rate than the current tertiary treatment with comparable retention times and lower dissolved oxygen concentrations. At colder temperatures, early results suggest that the biocatalyst was able to maintain an improved effluent quality compared to the NSFs. This technology has the potential to be a game changer for biological nutrient removal by overcoming seasonal performance variations.
