Nitrogen Removal Research

Removal of Nitrate by ‘Anoxic Absorbent Filtration’ and Carbon Addition

Published in Influents, 2009

Performance results of the WaterNOx, a biological anoxic filter for enhanced nutrient removal, are detailed from two separate field test sites.

Nitrogen Removal with the Waterloo Biofilter

Unpublished, 2004

An open letter to water and wastewater engineers details the biochemical processes involved in nitrogen removal, and provides supporting documentation from third party testing showing the nitrogen removal capabilities of the Waterloo Biofilter system.

Predicting Nitrification Efficiency from Dissimilar Wastewaters: Design Criteria & Operation Results

Presented at WEAO Conference, 2004

An underperforming aeration treatment plant is retrofitted with a Waterloo Biofilter as a polisher to meet ammonium levels for surface discharge. Operational data from two dissimilar wastewaters is used to successfully predict performance on a third wastewater.

Agricultural Mineral Soil Additives for Passive Nitrate Removal

Presented at NOWRA, 2017

Processes for removing sewage nitrogen at the individual residential scale must be low maintenance with only annual service visits. A passive autotrophic process using a 50-50 mixture by volume of: (a) agricultural sulphur for nitrate reduction, and (b) limestone for pH adjustment, in an up flow configuration, was field-tested at 8 – 34 hours hydraulic retention times (HRT) at one site and at 14 hours HRT at another. An HRT of 8 – 12 hours was found to be the minimum without substantial nitrate breakthrough; pH was fully neutralized and little BOD and TSS addition resulted. The mass of sulphate formed versus nitrate + oxygen removed reflects a simple stoichiometry, possibly requiring ammonium to be included, and with intercepts near the origin suggesting that gypsum is not precipitated.