Page 24

Odour Control first stage is an inorganic media biofilter sized for approximately 30 seconds of media contact time (empty bed resident time), requiring an overall footprint of 100 m2. This stage is used as a hydrogen sulphide roughing filter to drastically reduce the inlet hydrogen sulphide concentration. Inorganic media was required here to prolong the media life and maximize hydrogen sulphide removal. An organic media biofilter was not a good application for these high hydrogen sulphide concentrations as the media would quickly degrade and would require frequent changes. While a bioscrubber (bio-tower) could have been used in place of the inorganic media biofilter to accomplish this, on-site chemical (nutrient) storage and more complex operation precluded this from consideration. This inorganic biofilter consists of two concrete chambers with a HDPE flooring system to accommodate air distribution. The inorganic expanded clay media depth is 1.2 m and each cell has both in-bed drip irrigation and ceiling

mounted top spray irrigation. The units were fitted with low-profile insulated and removable FRP covers. Air leaving the first stage biofilters is captured in a pipe and sent directly to the second stage for further treatment.

Given the high hydrogen sulphide concentrations from the sulphide stripping chamber, a single biofilter was not adequate to accommodate expected odour concentrations. The second stage is a larger footprint organic media biofilter sized for a media contact time of approximately 60 seconds, requiring an overall footprint of 180 m2. The longer contact time serves to polish the remaining hydrogen sulphide. It also accommodates any volatile organic compounds and additional odour compounds in the foul air stream. An organic media unit is sufficient here as the hydrogen

GREEN TECHNOLOGY AT WORK ®

CASE STUDY Lallemand Bio-Ingredients, Inc. - Tara, ON

SOLUTION

ISSUE: Mineral enriched yeast

SOLUTION: Build 4,757m domed

PROBLEM: Converted powder ingredient plant starts production Spring 2014, but odor complaints shut production down by Fall 2014.

OUTCOME: Facility receives green light from MOECC to restart production by March 2015.

when mixed with water creates aersolized sodium selenite (Na2SeO3), which smells like horseradish and rotten eggs.

24 | November/December 2015

3

structure over water treatment basin to create containment for Hydroxylrich air injection. Fully automated Odorox® Technology safely destroys offensive fugitive odors.

sulphide concentrations are significantly less, at approximately 5 – 50 ppm. These lower concentrations will not impact the normal operating lifespan of the biofilter media. This biofilter consists of an HDPE liner with perforated incoming air pipe embedded in a drain rock media layer for air distribution. The organic wood chip media depth is 1.08 m and has both in-bed drip irrigation and top spray irrigation. Results The South Red Deer Regional Wastewater System went into operation in August 2015 and the resulting outflows from the Penhold lift station (the last lift station upstream of the odour management facility) have averaged approximately 7,500 m3/day. The removal rate of hydrogen sulphide has been approximately 99% since the installation of the organic media, with an average discharge hydrogen sulphide concentration below 2 ppm. James Coates, M.Sc., EIT is with Stantec Consulting Ltd. Email: james.coates@stantec.com

ODOR ISSUES?

Better Get Odorox® Hydroxyls! • NO Chemicals • Low Energy Cost • Small Footprint • Easy To Operate The most advanced solution for eliminating odors, decontaminating surfaces and purifying the air.

Call: 416.580.1244 4-21 Industry St, Aurora, ON L4G 1X6 www.hydroxylenvironmental.com Environmental Science & Engineering Magazine

Environmental Science & Engineering Magazine (ESEMAG) November-December 2015  

This issue features articles covering: Eliminating force main odour, controlling micro-pollutants in drinking water, Calgary's new grit remo...

Environmental Science & Engineering Magazine (ESEMAG) November-December 2015  

This issue features articles covering: Eliminating force main odour, controlling micro-pollutants in drinking water, Calgary's new grit remo...