2013 Technical Session 7 - Municipal Utility Operations

Monday, April 22, 1:55 - 5:00 pm, Vaseaux & Kootenay Rooms


Moderator: Peter Takacs, AECOM

 

7.1 JAMES Wastewater Treatment Plant – Digester Condition Assessment through Cleaning and Inspection

7.2 Maintenance for submersible pumps and wastewater pumping station automation systems

7.3 Treatment of Sludge Handling Return Streams Following Anaerobic Digestion

7.4 The Guide to Achieving the Best Performance of Your Primary Clarifiers Learning from Experience

7.5 Vibration - What is it? How does it affect my operation? What can I do about it?

 


Municipal Utility Operations | 1:55 pm - 2:25 pm
7.1 JAMES Wastewater Treatment Plant – Digester Condition Assessment through Cleaning and Inspection
Presenter: Nathan Koning, P.Eng., City of Abbotsford, Abbotsford, BC
Additional Contributors: Stella Chiu, P.Eng., M.Eng., LEED AP, City of Abbotsford, Abbotsford, BC; Ron Bernier, City of Abbotsford, Abbotsford, BC; Melvin Mayfield, P.Eng., City of Abbotsford, Abbotsford, BC; Peter Reid, M.A.Sc., P.Eng, Levelton Consultants Ltd., Richmond, BC

 


Constructed in 1981, the JAMES Wastewater Treatment Plant (WWTP) is a secondary effluent treatment plant which uses a Trickling Filter/Solids Contact (TF/SC) process. The Plant’s solids handling process includes a pasteurization system and three anaerobic mesophilic digesters, resulting in the production of Class A biosolids. The JAMES Plant treats the wastewater from Abbotsford, Mission and Sumas, and is co owned by the City of Abbotsford and the District of Mission. The City of Abbotsford operates the Plant. Digester No.1 was constructed in 1981 and consists of concrete walls and a floating concrete domed roof with a centre eductor tube. The digester has a volume of approximately 3,000 cubic meters and was last cleaned and inspected in 2003. To determine the asset replacement needs of the digester, the City hired a contractor in October 2012 to clean and remove the solids prior to an interior inspection. The City then retained a consultant to inspect the structural and mechanical components using a variety of methods. Repairs were recommended and prioritized as part of the inspection study. All phases of the work were scheduled to occur when the water level in the adjacent Fraser River was low. At the presentation, the City will share its experience, challenges and lessons learned through the cleaning, inspection and repair process.

Presentation PDF
 


Municipal Utility Operations | 2:30 pm - 3:00 pm
7.2 Maintenance for submersible pumps and wastewater pumping station automation systems
Presenter: Luc-Rejean Lepine, Eng., Xylem Water Solutions, Pointe Claire, QC
Additional Contributors: Jay Sommerfeld; Tony Santos; Don Chin; Marius Bocu, Moises Martinez

 


There are thousands of sewage lift stations in Canada and they play an important role in the wastewater treatment/transport systems. Manager's responsible for the wastewater operations must make sure that all their system components, including pumping equipment, are operating adequately to guarantee optimal efficiency and to respect environmental standards.  To achieve these objectives, an adequate maintenance of pumping equipment is essential, in addition to realizing how important savings are on their operation costs. Being non visible, pumping equipment is usually forgotten and only, when severally damaged are they maintained at high costs.  Essential and simple actions can be performed to avoid these situations.

Presentation PDF


Municipal Utility Operations | 3:05 pm - 3:35 pm
7.3 Treatment of Sludge Handling Return Streams Following Anaerobic Digestion
Presenter: Barry Rabinowitz, Ph.D., P.Eng., BCEE, CH2M HILL Canada Limited, Burnaby, BC
Additional Contributors: Tim Constantine, M.ASc., P.Eng., CH2M HILL Waterloo, Canada; Joshua Boltz, Ph.D., P.E., CH2M HILL, Tampa, FL, USA

The sludge handling return stream, or centrate, in a biological nutrient removal (BNR) plant having anaerobic digesters typically has high nutrient concentrations (primarily nitrogen and phosphorus) when compared with the incoming raw wastewater. This centrate sidestream is typically returned to the wastewater treatment plant mainstream for treatment together with the influent wastewater. While the centrate stream may represent

Presentation PDF

 


Municipal Utility Operations | 3:55 pm - 4:25 pm
7.4 The Guide to Achieving the Best Performance of Your Primary Clarifiers Learning from Experience
Presenter: Hany Gerges, Ph.D, PE, P.Eng, HDR Engineering, Walnut Creek, CA

 


A guide for optimizing primary clarifiers has been developed and successfully applied at a number of treatment plants.  This paper presents the author experience optimizing hundreds of primary clarifiers at many treatment plants all over the world with capacities ranging from 0.5 mgd (1,890 m3/d) to 1200 mgd (4,536,000 m3/d).  The guide outlines the optimization strategy for conventional as well as chemically enhanced primary treatment.  The objectives of optimizing primary clarifiers included; the reduction of aeration demand in the secondary treatment, increase the biogas production and/or reduction of effluent suspended solids to meet permit requirements. Simple field diagnostic tests were developed and applied. The data obtained from field tests were used to develop settling velocity distribution and primary clarifier rating curves under normal and peak loading conditions.  Using the collected data together with computational fluid dynamic analysis, clarifier performance enhancement features were developed, designed, constructed.  Performance verification testing was conducted to quantify the improvements. Performance enhancement features led to reduction in primary clarifier effluent suspended solids and biochemical oxygen demand and increase in primary sludge quantity.  The optimization guide presented in this paper could be easily applied at any treatment plant.
 


Municipal Utility Operations | 4:30 pm - 5:00 pm
7.5 Vibration - What is it? How does it affect my operation? What can I do about it?
Presenter: John Koch, PE, BCEE, HDR Engineering, Inc., LaConner, WA

 


End suction centrifugal, axial/propeller, and turbine pumps have been used for decades in wastewater systems.  All rotating equipment has some level of vibration, but at what point does this vibration become excessive and damaging to the performance and operation of the equipment.  With variable speed drives being used to meet the variation of flows within a pumping system, owners have reported problems ranging from excessive vibration and accelerated seal and packing deterioration to accelerated bearing wear.  Operating levels in the wet well have a dramatic effect on the level of vibration in a pump.  Typically low submergence of the pump suction will cause prerotation which leads to irregular velocity variations across the pump’s impeller.   This will lead to excessive and damaging vibration levels.  Another source of vibration in a pump can be the quality of the manufacturing of the pump and motor.  With variable frequency drives being used extensively in pumping application, the critical speed of the pump assembly including the pump shaft and motor shaft can have a dramatic effect on the vibration levels in a pump.  If the critical speed of the pump is below its operating speed, the chances of having excessive vibration when operating in the variable speed mode are very high. A comprehensive vibration testing program can be developed to minimize vibration and allow pumping station to operate satisfactorily.  Test results can optimize the pumping capacity of the station while providing maximum storage capacity.

Presentation PDF



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