Evoqua United States - Canada - EN

H2S Odours Eliminated with ZABOCS® System

Compact odour control system helps Canadian town eliminate treatment plant odours

A town located in the Western Canadian Rockies prides itself on its natural features that includes a river flowing through the middle of town.  The area provides residents and visitors with scenic trails, wildlife habitat, drinking water for the community. 

In 2014, a Western Canadian Rockies town expanded their 10 million liter per day (MLD) wastewater treatment plant and began experiencing an increase in H2S odours near a popular river walk trail  This issue required the town's municipal district to take quick action to find a solution to remediate it. 


The town and its water management contractor faced land space constraints, which is a challenge common to many treatment facilities.  Also, cold temperatures during the Canadian winters was another barrier which is typical to many wastewater treatment facilities in northern latitudes. 

During the evaluation of a solution, the town and contractor preferred a biofiltration odor control removal system, however the running of water would be a requirement for operation.  Also, the system would need to be installed in a climate controlled location to operate properly year-round when temperatures could reach -18°C (0°F).  Due to the climate and footprint concerns, a proposed system based on an in-ground tank was also evaluated, however rejected with the town continuing to look for an alternative solution.


After further evaluation of technologies it was determined that the ZABOCS® Biological Odor Control system from Evoqua Water Technologies would be an ideal solution to meet year-round operational requirements and space constraints, The ZABOCS system, a zero acclimation biological odour control process is a multi-media system that combines gas absorption, adsorption and biological treatment for capturing and elimination of organic and inorganic odours from wastewater process air streams. The ZABOCS system combines biological and carbon media processes allowing for odour control treatment three times the air volume compared to similar sized conventional biofilter systems. A primary biological stage removes most of the H2S odours, and a secondary polishing stage uses carbon to boost efficiency and provide extra capacity to handle spikes in H2S volume. In addition, the second stage provides odour removal instantly at start-up while the biofiltration stage is acclimating.

The ZABOCS system was delivered as a single package unit with a compact footprint to easily meet space requirements. The unit was also installed in a weatherproof enclosure, assuring continuous operation year-round.  Evoqua Water Technolgies provided engineering for this system and ongoing service as needed. 


The installation of the ZABOCS® system has provided 99.9% removal of H2S odours and over 99% of odour from the foul air stream, providing a pristine recreational and esthetic environment for the users of nearby homes, parks and hiking trails.

Evoqua’s advanced ZABOCS system technology helped the town eliminate treatment plant odour problems in a compact footprint with a solution that eliminated acclimation time and could operate in extreme cold.
The ZABOCS system meets the local odour removal requirements and has extra filtration capacity to support future growth, assuring a pristine recreational environment for residents to enjoy for generations to come.

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