Newsletter - May 2001
ARTICLES OF INTEREST FROM THIS ISSUE
The backbone of wastewater treatment -- preventing backpain
The backbone of wastewater treatment -- preventing backpain
The Professional Wastewater Operators, (PWO), organized a technical workshop at the Westin Harbour Castle Hotel in Toronto on Monday April 2, 2001. The technical workshop, entitled: Secondary Treatment, The Backbone of Wastewater Treatment -- Preventing Backpain, was presented in conjunction with the WEAO technical symposium and was attended by professionals from a wide variety of backgrounds.
The challenge in organizing such a workshop, lies in providing an enthusiastic audience with innovative tools which they can then share with colleagues in their own facilities. This year's topic was geared towards offering specific tools for monitoring the conditions or trouble shooting problems associated with the secondary treatment system of a wastewater treatment facility.
Sound good? Well, any successful workshop hinges on the quality of the speakers. We were indeed fortunate to have many quality speakers agree to share their vast expertise: Dr. Mano Manoharan, Ontario Ministry of the Environment, Jan Kochany, Conestoga-Rovers and Associates, Alan Werker, University of Waterloo, Linda Ferguson, XCG Consultants, and Mike Newbigging, Hydromantis. The day was topped off with an exciting tour of Toronto's Western Beaches Tunnel, and it also gave us the opportunity to get our heads out of secondary treatment and into Combined Sewer Overflow (CSO) control.
The first paper was presented by Dr. Mano Manoharan, a seasoned presenter with over 12 years of experience. In his presentation on Innovative Treatment Technologies, Mano explained how more innovative and cost-effective treatment technologies are currently being considered for expanding or upgrading treatment facilities as a result of a growing population and more stringent effluent quality requirements. Three major categories identified in Mano's presentation were: Optimization Techniques, Nutrient/Toxicity Removal Technologies and Specific Treatment Systems.
The Optimization Technique was described as being a cost-effective approach to upgrade and/or expand a treatment facility. Even if treatment units need to be added to upgrade and/or expand the existing facility, the magnitude of the upgrade/expansion can be minimized if the existing facility is first optimized. Some examples of Nutrient/Toxicity Removal Technologies include dual and triple point chemical additions for phosphorus removal. Another was described as a green alternative that uses the enhanced biological phosphorus removal process (known as Bio-P) which uses no or reduces chemicals.
Mano explained that one of the principal causes of toxicity in effluents from municipal wastewater treatment plants is ammonia. Some of the methods of removing ammonia include the Nitrification process, biological nutrient removal (BNR), on/off aeration and biofilters. Examples of Specific Treatment Systems include, sequential batch reactors (SBR) technology, which are gaining in popularity and membrane bioreactors (MBR).
The second speaker was Jan Kochany, who has published 76 papers on water and wastewater, environmental chemistry, photochemistry and analytical chemistry. Jan's paper, Application of Respirometry in Wastewater Treatment, described what respirometry is and how it may be used in the field of wastewater treatment.
Jan explained how Respirometry analysis allows simultaneous monitoring of biochemical oxygen demand (BOD) in several reactors at a precisely controlled temperature. There are basically two different types of respirometry analysis, aerobic and anaerobic analysis. In both cases, the reactors are fed with the same amount of biomass but different concentrations of the investigated waste. The growth response of the biomass to the organic substances present in the investigated wastes, which comprise of food and bacteria, can be monitored by measuring the oxygen uptake for aerobic analysis and the biogas generated for anaerobic analysis, in each reactor connected respirometric system. The reduction in biological activity (oxygen uptake or biogas production) is related to the inhibitory effect the waste product had on the biomass and therefore the increased potential of affecting your treatment process.
The result is that Jan can then indicate to operations, even prior to you accepting to treat a certain waste product at your plant, if and when this waste product may be inhibitory to your biomass. Jan showed how respirometry benefited his clients, and listed examples such as the effect of landfill leachate on a treatment system, feasibility of biological treatment of various automotive waste streams and in determining which method, aerobic or anaerobic, would be more suitable to treat chemical industrial waste. This presentation offered monitoring techniques which were new to many of us.
Alan Werker presented the third paper of the session: Applied Microbial Ecology for the Control of Wastewater Treatment System. Although the title seems a little technical in nature, Alan's unique presentation style and use of analogies to relate his points to everyday occurrences was well received. From his catchy opening question: "If microorganisms could talk, what might engineers and plant operators ask the microbial community?" the audience was hooked. Alan's key point was that the evolution of the microbial community structure of biosolids is a selection process that can be purposefully manipulated and that upsets are nothing more than this selection process gone awry.
He stressed that early detection is key to proactive corrective measures and prevention of discharge violations. Alan's research looks specifically at the microbial fatty acid (MFA) compositions contained in biosolids. There are many different chemical forms of fatty acids and each species of microorganisms has a unique MFA combination that is linked directly to their genetic makeup. So, what does this all mean? It means that Alan is looking into 'fingerprinting' biomass so that he can develop pattern recognition and ultimately anticipate plant upsets before they occur. This would allow the operator to make specific changes based on data to return the microbial population back to optimum conditions while avoiding any effluent exceedances.
The audience eagerly anticipated the presentation by Linda Ferguson: Process Optimization -- Optimizing Secondary Clarifier Performance To Improve Effluent Quality. Linda is well respected throughout North America with her involvement on a wide variety of major wastewater treatment plant optimization studies. Linda's toughest challenge was determining what topic to present, and we feel clarifier performance was an excellent selection for this workshop.
Simply stated, the performance of the secondary clarifiers determines quality of the treatment plant effluent. Failure of the secondary clarifier results in poor effluent quality characterized by high effluent solids concentration. Linda listed the three basic types of secondary clarifier failures to be hydraulic failure, solids flux failure and floculation failure. This should not discourage the operator because if properly identified, corrective action can be taken. Techniques used to determine the method of failure include, clarifier stress testing, clarifier dye testing, FSS/DSS testing and solids flux testing. Once identified, correction action may include baffling techniques, improving RAS efficiency and reducing the solids loading to the clarifier during high flow conditions.
The fifth paper of the day: Plant Investigation Using Dye, was presented by Mike Newbigging. Mike has over 16 years of experience in wastewater process engineering and optimization. The idea of using tracer dye for plant investigation at wastewater treatment facilities is not commonly contemplated, but Mike explained all the different applications where dye can be used and the benefits associated with each of them.
This paper demonstrated how dyes and tracers may be used to identify mixing characteristics, flow splits, reactor kinetics and effective retention times, as well as to determine flow meter accuracy and potential cross-connections. The two basic test techniques in tracer testing include dispersion (slug) addition or flow pattern (constant rate) addition. The dispersion test is generally used to determine the actual HRT of a desired basin, to estimate the degree of hydraulic short-circuiting or bypassing and the effective level of mixing provided in an aerated basin. A flow pattern test consists of pumping the tracer at a known rate and concentration over a period of time upstream of the unit process and collecting samples at different locations and depths. This test can be used to evaluate the spatial distribution of flow through a unit process including the location of dead zones, density zones and the effect of baffling arrangements.
Mike then described a variety of projects where he successfully used tracer dyes to investigate plant problems and discussed the benefits associated with each of those evaluations. This was an excellent presentation in which I'm sure we all saw instances where one of these applications could benefit our own facilities.
After a full day of absorbing all of these possibilities for improving secondary treatment, we thought the participants would enjoy a field trip and some fresh air. The City of Toronto was kind enough to arrange for a tour of their newly designed Western Beaches Tunnel. Although this had little to do with our theme of secondary treatment, the Tunnel system is so incredible it would surely impress the most accomplished professional.
The system has the capability to intercept and collect up to 85,450 m3 of combined sewage that would normally be discharged into Lake Ontario, and pumps it to their WWTP once flows in the collection system and at the plant subside to acceptable levels. The sheer size is incredible and the automated on-line analyzers that continually monitor the parameters of the flow constituents, are considered by many to be leading edge technology.
Once certain pollutants fall below levels acceptable for discharge to the Lake, a valve opens allowing discharge, while being treated with ultraviolet disinfection. The benefit is that the Lake receives a CSO discharge that is cleaner and treated for the pollutants which historically contributed to beach closures. The added benefit is it reduces unnecessary volume to be treated at the WWTP making available capacity for higher strength flows.
The tour was a great success. As this system was not yet commissioned at the time of our tour, the workshop participants were lucky enough to enter and descend to the bottom on one of the massive vertical shafts. Some of the brave were even taken on a short hike up the main tunnel, approximately 100 metres, an experience all of us will not easily forget.
The Professional Wastewater Operators, Ontario would like to express their gratitude for the sponsorship provided by Eaglebrook Inc. of Canada, to each of our speakers, and to David Parrish of the City of Toronto, for arranging the tour of the Western Beaches Tunnel.
The Secondary Treatment workshop proceedings are available in a hard copy format, for a nominal charge. Contact Jeffrey McIntyre, Tel: (905) 540-5662, for more information.
Dan Chauvin, City of Hamilton
Representatives of the WEAO Biosolids Committee, along with WEAO President Bill DeAngelis, met with Keith West, Director of MOE's Waste Management Policy Branch, on March 29, to present some of our industry's concerns related to the biosolids beneficial use program in Ontario. A lack of public confidence in the program, largely related to the low visibility of MOE in monitoring and enforcement activities, is jeopardizing the sustainability of biosolids land application in many jurisdictions.
The goal of the meeting was to establish a dialogue between WEAO and MOE in order that the technical expertise represented within WEAO can be made available to MOE as it considers some of the issues related to the beneficial use of biosolids in the future. As a result of the meeting, WEAO was asked to provide comment to MOE on several priority issues related to biosolids management. Hopefully, this was the first of many productive meetings that will be held on the subject of biosolids between WEAO and representatives of MOE.
Biosolids research in Ontario
Dr. Beverly Hale, University of Guelph, Department of Land Resource Science, in collaboration with the Ontario Ministries of Environment (MOE) and Agriculture, Food and Rural Affairs (OMAFRA), is planning a study to determine the concentrations of metals that are not being regulated in Ontario sewage biosolids and agricultural soils. These metals are referred to as the "non-regulated" metals.
The literature review study coordinated by WEAO indicated that sewage biosolids and soil limits for the 11 metals stipulated in the Ontario Guidelines for the Utilization of Biosolids and Other Wastes on Agricultural Land, are adequate. These limits were established based on rigorous scientific studies. There is, however, a need for more accurate data to determine if limits are needed for non-regulated metals, such as silver, antimony, etc., in biosolids.
The project proposes to analyze sewage biosolids samples collected from 25 municipal sewage treatment plants and from 160 to 200 agricultural fields for a long list of non-regulated metals. Dr. Hale will be asking selected municipalities to provide historical data as well as monthly sewage biosolids samples for a period of 12 months. The data will be used to determine if limits and/or further studies (e.g. phyto-toxicity studies) are necessary for some of the non-regulated metals.
The Regional Municipality of Niagara, in collaboration with MOE and OMAFRA, will be conducting a field study to determine the effect of storage time on the occurrence and quality of runoff water and leachate from sewage and paper mill biosolids piles that are temporarily stored on farms prior to their incorporation into the soil. Impermeable sheets and barriers will be used to contain runoff water and leachate from the biosolids piles.
Biosolids, runoff and leachate samples will be collected during rainfall and simulated rainfall events and analyzed for various chemical and microbiological parameters. Results will be used to develop Best Management Practices for biosolids land application programs.
WEAO technical sessions focus on biosolids issues
The WEAO Biosolids Committee, in cooperation with the Conference Committee, organized two sessions at the Annual Conference appropriately entitled: Biosolids Management -- The Challenge of Tomorrow.
The morning session, co-chaired by Janice Patterson of OMAFRA, and Don Hoekstra of Azurix North America, focused on the biosolids management issues facing generators. Long-term biosolids management plans being developed in the Regions of Peel and Niagara were discussed by Deborah Ross of KMK Consultants, and Joe Furgal of Region of Niagara, respectively. Randy Jankiw of OMAFRA, provided an update on nutrient management planning in the province and the relationship to biosolids land application programs. Dr. Mel Webber of M.D. Webber Environmental, reported some of the recommendations that resulted from the WEAO-sponsored literature review on contaminants in biosolids.
The afternoon session, co-chaired by Volker Masemann of Earth Tech Canada, and Stephen Nutt of XCG Consultants, involved presentations on a number of technological innovations related to biosolids treatment. Perry Schafer of Brown & Caldwell, discussed process and design changes that have successfully improved the biosolids quality produced from the anaerobic digestion process. Hugh Monteith of Enviromega, introduced a new digester mixing technology. Don Holland of Acres & Associated, talked about the upgrade to the Tillsonburg digesters. Jeffrey Burnham of J.C.Burnham Co., and Grant Mills of N-Viro Systems, introduced the audience to biosolids processing technologies that produce a superior quality biosolids product.
All sessions were well attended and thought-provoking. Our thanks to the speakers for their excellent presentations.
Steve Nutt, XCG Consultants
Contributions should be directed to Stephen Nutt at: stephen@xcg.com or Janice Patterson at: janice.patterson@omafra.gov.on.ca.