Stream B: Wastewater Issues


2.1 Are automatic grease recovery devices (AGRD) as good as the manufacturers claim?

2.2 Thinking outside the engineering box: Interactive, theme-based technologies for a new urban wastewater treatment plant

2.3 Operation De-Rag – A case study in combating pump blockages


7.1 Evaluating the implications of sewage heat recovery on wastewater treatment plants using a sewage heat energy balance

7.2 Relative rerformance of grit removal systems

7.3 Condition assessment of highbury interceptor using non-destructive methods

7.4 Upgrading lagoons to remove total phosphorus and nitrogen

7.5 Hawkesbury: First IFAS plant in Canada

7.6 Best design practices for odour management of wastewater applications in a dense urban environment

7.7 Building utilities in an urban environment – Gilmore pump station



2.1 Are automatic grease recovery devices (AGRD) as good as the manufacturers claim?

Presented By: Douglas Adams, Capital Region District.
Time: Monday, 2:00 - 2:30 PM

For many years the Capital Regional District, in Victoria, BC, would not accept AGRD as an alternative to the traditional mechanical gravitational grease interceptor. The claims made by the manufacturers were never fully supported with credible scientific evidence or real-time testing in 'real-life' situations. In 2012, the decision was made by the Regional Source Control Department to conduct a number of closely monitored trials at a fast-food burger restaurant. To date two AGRD and two mechanical gravitational grease interceptors have been trialed with varying results and a lot data was collected. This session will reveal what actually happened during the trial. What problems were encountered and what solutions were implemented? It will reveal some interesting findings regarding the effectiveness and efficiency of these devices under extreme working conditions. So are AGRD better than mechanical gravitational grease interceptors?

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2.2 Thinking outside the engineering box: Interactive, theme-based technologies for a new urban wastewater treatment plant

Presented By: Joyce Chang, CH2M Hill.
Time: Monday, 2:30 - 3:00 PM

Selection of wastewater treatment processes is often based on engineering-focused criteria such as influent wastewater characteristics, effluent discharge requirements, track record of proven technologies, ease of operation and maintenance of equipment, and site constraints. The design of the new Lions Gate Secondary Wastewater Treatment Plant adopted a theme-based mapping and interactive approach in selecting a preferred option from a long list of technologies for liquid stream treatment, solids management, and integrated resource recovery. The process selection framework involved collecting and bundling ideas from an integrated design team and stakeholders of diverse background to develop distinct concepts that feature relationships of the treatment facility with the community, natural environment, recoverable resources, and surrounding industries. Technologies were then linked to these thematic concepts for evaluation and trade-off analysis using technical, community-related, environmental, and economic criteria.

This presentation will discuss how the decision-making framework led to the selection of treatment technologies for a 100 ML/d plant that meets multiple project goals while fitting onto a narrow 3-hectare site. Liquid treatment processes include compact lamella settlers, deep tank activated sludge, and stacked secondary clarifiers that can be adapted to meet future regulatory changes. Solids management strategies include thermophilic digestion to produce Class A biosolids and utilization of biogas for in-plant and off-site energy use. The design also incorporates reclaimed water tertiary filtration, sidestream deammonification, and two-stage odour control.

This presentation will be of interest to decision makers, managers, and engineers who need to develop solutions for projects involving various stakeholders and multi-faceted objectives.

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2.3 Operation De-Rag – A case study in combating pump blockages 

Presented By: Devin Kiyonaga, Metro Vancouver.
Time: 3:00 - 3:30 PM

Clogged pumps, a.k.a. ragging, costs the industry millions of dollars and increases the risk to worker safety. There is a variety of technologies to combat these pesky rags, including in-line grinders that grind rags to a pulp, pumps that chop, slice, and dice, and an array of screw pumps and special impellers designed to pass the rags through. Deciding how to approach the problem of ragging is a difficult one, often dictated by cost and level of complication. This was the case at Metro Vancouver's Baynes Rd Pump Station. Operators were de-ragging several times a week, sometimes during the night and on weekends. The culprit? Mostly wet-wipes and fabrics that clump together and form an impassable ball of knotted material. We wanted a solution that would reduce the number of call-outs and require little to no change to infrastructure. Grinders and specialized pumps would require new discharge piping, power upgrades, and alterations to the building structure. Instead, we retrofitted an existing pump with a new "ripping" impeller, requiring no major changes. Unlike a chopping pump, this impeller rips rags apart as they pass through the volute. So far, its performance is impressive. With the new impeller, the pumps have ragged only once within 6 weeks.

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7.1 Evaluating the implications of sewage heat recovery on wastewater treatment plants using a sewage heat energy balance

Presented By: Wayne Wong, Kerr Wood Leidal Associates Ltd.
Time: Tuesday, 8:00 - 8:30 AM

Sewage heat recovery (SHR) projects, implemented in the wastewater collection system, may have unintended impacts on available heat energy at a downstream wastewater treatment plant (WWTP). This in turn may degrade the effectiveness of treatment processes at the plant. To assess potential opportunities for and risks of sewerage heat recovery in the Metro Vancouver collection system, a sewage heat energy balance model was created for each of Metro Vancouver's four WWTPs. The model correlates the impact of influent temperature changes to the theoretical heat energy gains and losses at the WWTPs. Sewage heat gains and losses in each major treatment process were combined into a heat energy balance for the overall treatment system.

The model quantifies the additional heat energy needed in the treatment plants as a result of a drop in the influent sewage temperature caused by SHR projects. The model also identifies the largest heat energy gain and losses in the process, and predicts the seasonal wastewater temperature variations due to the net sewage heat flux.

The impact of theoretical SHR projects on WWTP mixed liquor temperature is a key model output. The model was used to establish SHR project parameters (flow and/or temperature) so that the cumulative effects of SHR projects do not adversely affect biological processes. The correlation between reduced mixed liquor temperatures and the resulting heat energy deficits in anaerobic digestion was also estimated. The model was also used to quantify the heat energy available for extraction in the effluent discharge from the WWTPs.

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7.2 Relative performance of grit removal systems 

Presenter: Lindsey Schwitzer, Hydro International.
Time: Tuesday, 8:30 - 9:00 AM

The importance of efficient grit management practices has become a high priority for many treatment plant operations in order to extend equipment life and reduce operating costs. As biological treatment processes continue to evolve to produce better effluent quality in a smaller footprint, pretreatment for grit removal is a crucial step in the overall process. The purpose of this paper is to present data from performance testing of various grit removal systems, generated by a repeatable sampling and analysis methodology, to compare virtually all commercially available grit removal technologies and their removal efficiencies.

British Columbia has multiple high profile projects in development, including the first secondary treatment facility in Victoria and a new facility to replace the Lions Gate WWTP in Vancouver. These projects will use process equipment, which require advanced biological treatment processes in a small footprint.

Grit is a nuisance material that causes wear to equipment, increasing maintenance and operational costs while reducing equipment performance and useful life. Choosing a grit removal technology has often been based on equipment price with little regard for device efficacy and consequent grit removal efficiency. Decision-makers are often forced to differentiate amongst various, and often conflicting, performance claims from equipment manufacturers. In the absence of an accepted, peer-reviewed test standard for grit sampling and analysis, equipment selection is frequently sub-optimal.

This paper encapsulates data from performance testing of various grit removal systems with the data having been generated by a repeatable sampling/ analysis methodology for comparing virtually all grit removal technologies and their removal efficiencies. Armed with such information, decision-makers can make better technology decisions as it pertains to grit management. High performance grit removal systems can lead to substantial cost savings through reduced maintenance/repair work due to abrasive wear and reduced digester cleaning intervals.

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7.3 Condition assessment of Highbury Interceptor using non-destructive methods

Presented By: Meghdad Hoseini, Levelton Consultants Ltd.
Time: Tuesday, 9:00 - 9:30 AM

The Highbury Interceptor pipe conveys sewage effluent from the City of Vancouver and from southwest Burnaby to three submarine siphon pipes that feed the effluent beneath the North Arm of the Fraser River to the Iona Wastewater Treatment Plant. Severe deterioration of the reinforced concrete was observed within the junction and diversion chambers during the siphon pipe coating remedial work and a detailed condition assessment of the reinforced concrete was deemed necessary.

Due to a lack of redundancy in the system and the high rate of effluent flow (average daily volume is approximately 471 million liters), the chambers connecting the interceptor pipe and the siphon pipes cannot be isolated and temporarily removed from service to facilitate worker entry for the condition assessment work.

A nondestructive approach from the exterior surfaces of the Chambers was preferred and included:

• Visual review of the chamber interior using a CCTV video feed and a high-resolution photography;
• Impact-echo (IE) testing of the surfaces to estimate residual concrete thickness;
• Ground Penetrating RADAR (GPR) to estimate the depth of embedded steel reinforcement;
• Elevation Survey of the top surface of the roof slab;
• Profiling of the interior surfaces of the chamber using a three-dimensional laser to measure the interior dimensions

The results show that the reinforcement in the roof slab has been exposed at sizable areas due to combination of scour and softening of the concrete paste by microbiologically induced corrosion. Conceptual approaches for remedial work are also presented to restore the diminished capacity of the concrete.

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7.4 Upgrading lagoons to remove total phosphorus and nitrogen

Presented By: Merle Kroeker, Nelson Environmental Inc.
Time: Tuesday, 9:30 - 10:00 AM

Due to increased concern across North America regarding the health of lakes and rivers downstream of municipal and industrial wastewater treatment plants (WWTP), improving water quality from existing WWTP (as well as new processes) has become a high priority.

Historically, most lagoon systems were designed to remove BOD and TSS from the wastewater stream. Increased focus on the effect of effluent toxicity in the receiving stream, along with possible eutrophication of lakes and rivers, has resulted in new requirements for nitrification of ammonia, and removal of both phosphorus and nitrogen.

Lagoon Phosphorus removal is accomplished by chemical addition and filtration. While phosphorus removal is an established process, ongoing development work continues to lower chemical dosing requirements and improve removal efficiencies when utilizing the process to upgrade lagoon systems.

Since early 2006, Nelson Environmental Inc. has developed and verified the performance of an aerated Submerged Attached Growth Reactor (SAGR) for nitrification, the first stage of the nitrogen removal process.

While the SAGR process has provided conclusive proof in terms of cold climate nitrification following an aerated lagoon system, little work had been done on a denitrification process that can operate at the same low water temperatures. While in theory, denitrification is not inhibited by cold water to the same extent as nitrification, a process operating at full design load and flow was required to demonstrate total nitrogen removal.

In the summer of 2012, a demonstration site was constructed and commissioned in Blumenort, Manitoba. The total nitrogen removal system consists of an anoxic attached growth reactor, followed by a nitrification SAGR.

The upgraded lagoon systems meet increasingly stringent effluent limits, while maintaining the desirable properties of low overall maintenance, simplicity of operation, and long-term reliability that originally made lagoon systems popular.

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7.5 Hawkesbury: First IFAS plant in Canada

Presented By: Daniel Lamarre, Veolia Water Solutions and Technology Canada Inc.
Time: Tuesday, 10:20 - 10:50 PM

For decades now, Canadian Cities have elected to construct Activated Sludge Systems as their main Biological component to treat Municipal Wastewater. This solution, ever popular and considered as the basis of biological wastewater treatment, presents the clear advantage of remaining very stable and highly efficient under any kind of use, while providing a wide variety of removal potential. By the same token, the system clearly remains a good compromise, reducing the requirements for advanced primary clarification upstream. However, the station grows older while the urban development of any City, Town or Region continues, challenging the Activated Sludge System size and global performance. IFAS was introduced on the market some years ago to increase Activated Sludge Systems longevity and budget friendly value. The technique of introducing media fixing the organic growth help multiply the Activated Sludge System capacity and thus present a sensible option to existing system reaching or exceeding their treatment capacity. The current paper will present the design conditions and the actual field test results of the first IFAS System installed and operated in Canada. The paper will emphasize the performance of the system in both summer and winter conditions, providing a practical snapshot at real Canadian cold-water conditions application of the IFAS system.



7.6 Best design practices for odour management of wastewater applications in a dense urban environment

Presented By: Reter Matensson, Biorem Technologies Inc.
Tuesday, 10:20 - 10:50 AM

Increasing urban encroachment on wastewater treatment facilities and their collection systems creates a number of challenges for those involved with ensuring that those processes do not cause a negative impact to the surrounding community. The most common challenges are related to quality of life of the nearby residents and manifest themselves in terms of odour, noise, and aesthetics.

Traditional solutions using "catalogue" or "off the shelf" adsorption systems, chemical scrubbers or conventional organic based media biofilters have a variety of shortcomings that seriously impact the viability of having a successful project executed.

The following paper is intended as a Manual of Best Practices for environmental professionals interested in applying the latest developments in advanced odour control techniques. These approaches safeguard aesthetics while ensuring that the highest rates of treatment efficiency can be achieved in a reliable and long-term manner.

Several case studies with commensurate data and graphics will be presented that illustrate the principles outlined in the document.

 pdf icon Presentation PDF



7.7 Building utilities in an urban environment - Gilmore pump station

Presented By: Yariv Ben-Shooshan, Opus DaytonKnight.
Time: Tuesday, 10:50 - 11:20 AM

On the surface of this project it was just an old pump station that required replacement to meet future flows. Through the presentation of this sewage pump station project we will demonstrate some of the new trends of constructing facilities that not only provide an engineered solution but also blend with the environment and include features to engage with the public. This will be provided in the context of other facilities to demonstrate the City of Burnaby advanced approach to construction of above ground infrastructure in public areas.

The paper will describe some of the features specific to this project. It would also cover the benefits and the risks and additional costs that should be considered when going that route. The Gilmore sewage pump station is located in a dense, high traffic area right under a Sky Train station in the City of Burnaby.

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