Report to / Rapport au :

Environmental Services Committee /

Comité des services de lenvironnement


and Council / et au Conseil


26 March 2002 / le 26 mars 2002

Submitted by / Soumis par : Dick Stewart, General Manager /Directeur Général People Services Department/ Services aux citoyens


Contact/Personne-ressource : Dr. Robert Cushman, Medical Officer of Health /

Médecin chef

Public Health and Long-Term Care / Santé publique et des soins de longue durée

724-4122 ext.  23684




Ref No:  ACS2002-PEO-HEA-0004


SUBJECT:     A Review of Land Application of Biosolids in the City of Ottawa


OBJET :         Un examen de l’épandage des biosolides sur le sol dans la Ville d’Ottawa





That the Environmental Services Committee and Council approve that:


1.      The Medical Officer of Health recommends continuing land application of biosolids in the City of Ottawa with implementation of proposed Best Management Practices;

2.      To ensure optimum program management, TUPW staff will undertake a yearly review of the Biosolids Land Application Program starting at the end of the 2002 land application season;

3.      The Medical Officer of Health will continuously monitor new and emerging scientific literature on biosolids and report back to TUPW staff and Council accordingly.





Que le Comité des services de l’environnement et le Conseil municipal approuvent que :


1.      le médecin chef en santé publique recommande de continuer l’épandage des biosolides sur le sol dans la Ville d’Ottawa en mettant en oeuvre les meilleures pratiques de gestion proposées;


2.      le personnel de TSTP effectue un examen annuel du Programme d’épandage des biosolides sur le sol à partir de la fin de la saison d’épandage de 2002 afin d’assurer une gestion optimale dudit programme;


3.      le médecin chef en santé publique se tienne informé, de façon continue, de toute nouvelle documentation concernant les biosolides et fasse rapport au personnel de TSTP ainsi qu’au Conseil municipal en conséquence.





In December 2001, Ottawa City Council instructed the Medical Officer of Health to retain experts to conduct a scientific review of the safety of spreading biosolids on farmland, and to develop standards for land application of biosolids that meet or exceed current Province of Ontario guidelines.


Biosolids, also called sewage sludge, are a byproduct of the sewage treatment process at Ottawa’s R.O. Pickard Environmental Centre.  They are formed by separating solids from wastewater and by conversion of soluble organic pollutants to biomass.  These solids are then stabilized, which reduces the concentration of pathogens (disease-causing organisms).


The R.O. Pickard Environmental Centre produces roughly 40,000 wet tonnes of biosolids every year – or four truckloads a day.  Approximately 20,000 tonnes are spread on local farm fields free-of-charge for use as a fertilizer alternative to farmers.  Because biosolids cannot be spread in winter and there is no local storage facility, the remaining tonnes are exported to composting facilities and other re-use options outside the City.


Biosolids contain nutrients including nitrogen and phosphorus, and for that reason the material enriches soil and improves crops.  Currently, demand from farmers for biosolids surpasses supply.  Members of the public have raised concerns about potential human health and environmental risks of applying biosolids to land.  The current wastewater treatment does not completely eliminate pathogens or all of the pollutants in the raw sewage, which includes waste from industry.  Research on the subject is ongoing, particularly with regard to substances that may be found in biosolids such as pathogens, some metals, estrogenic hormones, pharmaceuticals and flame retardants called PBDEs.


Of the biosolids generated at the 50 largest sewage treatment plants in Canada, approximately 45 per cent, or 2 million tonnes per year (on a dry weight basis) are applied to land.  In Ontario, biosolids have been spread on farmland for several decades. Last year, the City of Ottawa’s Biosolids Program spread on 27 farm sites, representing less than one percent of the City’s total agricultural acreage. Note that five years must pass before a second spreading takes place on a site, and repeats to date are rare.


Ottawa’s current biosolids program was approved in 1997 and underwent an extensive review and update in 2001.  This review entailed many public consultations.  Under the updated plan, staff recommended that the existing program continue in the short term.


As a result, Ottawa City Council accepted the Biosolids Management Plan Update in December 2001.  The recommendations of the Management Plan update were the following:

·        Continue to manage the disposal of municipal biosolids consistent with the principle of beneficial reuse

·        Develop multiple end uses

·        Develop a biosolids Environmental Management System

·        Strengthen the Sewer Use Control Program

·        Initiate further research into key areas

·        Develop a Biosolids Management Public Awareness and Communication Plan that provides ongoing information about the Biosolids Management Plan


At the same time, Council directed the Medical Officer of Health to retain experts to conduct a scientific review of the safety of spreading biosolids, then present the analysis and new standards to the Environmental Services Committee.  Meanwhile, no biosolids would be applied to agricultural land until the Medical Officer of Health’s report was received.


The Medical Officer of Health hired the services of Apedaile Environmental Management and CH2M Hill Canada Limited because they had done previous work on this issue.  They were assigned to compile current literature on health aspects of biosolids, interview researchers, and develop – in consultation with City Staff - Ottawa-specific Best Management Practices.  To assist the Medical Officer in his determinations, a third party expert (Dr. Donald Cole, M.D., an environmental health specialist at the University of Toronto) was brought in for his advice on the project.  More details on this can be found below.





Throughout history, societies have struggled to find ways of coping with human waste. Every resident of Ottawa helps produce what eventually ends up at the sewage treatment plant, making this a community issue.  Biosolids will not disappear – they need to be placed somewhere in a manner that has the least negative impact on public health and the environment.  Beneficial re-use of biosolids can be regarded as a long-term means of promoting a sustainable city.


Because biosolids contain many substances and are applied to a complex environment, uncertainties exist, and these uncertainties will likely exist for years to come.  New concerns will no doubt arise, as land application is a developing practice that is subject to an increasing amount of research.  Therefore, using the words ‘safe’ or ‘unsafe’ to describe the use of biosolids is simplistic and unwise.  Instead, any assessment of a biosolids program should be based on the potential for benefits and the management of potential risks.

To ensure optimum management, staff of the Transportation, Utilities and Public Works Department (TUPW) will undertake an annual review of the Biosolids Land Application Program starting directly after the end of the 2002 application season.  The review will monitor compliance of the Best Management Practices and propose changes if required.  Furthermore, the Medical Officer of Health will continuously monitor new and emerging scientific literature on biosolids and report back to TUPW staff and Council accordingly.  In this way, the public can be assured that practices are based on the latest research findings and that protection of public health remains paramount.


Below is a brief summary of the full review conducted by Apedaile Environmental Management and CH2M Hill Canada Limited.  Please refer to the full report, entitled “Health Aspects of Biosolids Land Application,” for a more detailed examination.  The report contains three main sections – 1)Methodology  2)Scientific Review  3) Best Management Practices.




Project staff compiled and documented research on the health effects of biosolids.  The starting point for this work was a literature review commissioned by the Water Environment Association of Ontario (WEAO), which was completed in April 2001.  The WEAO report looked at the full range of contaminants in biosolids and identified which groups of contaminants should be the focus for further study.  These groups then became the focus for the Apedaile/CH2M Hill investigation.  In total, 168 articles were compiled and read for the final report.


Project staff also interviewed nine biosolids researchers/experts, representing different views, to provide context to the published work and to discuss emerging issues.  The researchers were asked about implications of their research for municipalities spreading biosolids.  Transcripts of these interviews are included in the full report.


Best Management Practices were developed for Ottawa’s program.  During public consultation for the Biosolids Management Plan Update in 2001, a recurring theme was lack of confidence in the existing guidelines.


Lastly, environmental health expert Dr. Donald Cole advised on the project from beginning to end.  He visited Ottawa in March to meet with the Medical Officer of Health and members of the project team for a full day to review scientific rationale for determining Best Management Practices.  Dr. Cole gave regular feedback throughout the process.  An associate professor of community medicine/epidemiology in the Faculty of Medicine at the University of Toronto, he has extensive experience in the field of environmental health as a medical doctor, scientist, and educator.


All tasks were completed during a three-month period from January to the end of March 2002.

Scientific Review


The project team examined different kinds of studies on the health effects of biosolids, providing a variety of perspectives. Research ranged from epidemiological cohort studies (e.g. comparing the health of exposed and unexposed farmers) to the fate of specific biosolids contaminants such as estrogenic hormones.


The report identified the research challenges of determining the potential health effects (if any) to biosolids, as in many other areas of environmental epidemiology.  Specialists in the field range from engineers to microbiologists, all studying different aspects of biosolids application.  “The result is that none of the papers reviewed addressed all components, given that the constituents of different forms of biosolids may vary substantially, as do methods of application (and hence exposures) and health outcomes of relevance (e.g. infection versus irritation),” the report states.  In general, few studies gave consideration to exposures other than biosolids that might confound the biosolids-health effects relationship.  Further, the group of relevant studies on exposure to biosolids included both heterogeneous population (sewage treatment plant workers, neighbouring application sites) and heterogeneous study designs”.


Still, it was encouraging to note that biosolids in Ottawa are applied more cautiously than in other North American jurisdictions where much of the research was done.


Disagreement among scientists was evident in the scientific review.  For instance, the WEAO report recommended further investigation of several unregulated metals such as silver, thallium and lead, but in an interview with the project team, Dr. Rufus Chaney (U.S Department of Agriculture) argued that high applications of these metals will have little effect on soil composition.  “Until you have reason to believe that there is a risk to humans from the highest transfer pathway, you shouldn’t be regulating it,” he said.  Other experts are more cautious.  Ellen Harrison of the Cornell Waste Management Institute, speaking about a recommendation made by her group regarding land application of sewage sludge stated, “It was a cautionary statement. It did not say don’t do it, it simply said if you are going to do it, make sure (you) get test results, apply clean sludges, more conservative soil values”.


The review listed two emerging issues – bio-accumulative contaminants called PBDEs, and the potential physical health effects of odours.  Please see the report for a full discussion.  People do generally find biosolids unpleasant-smelling.  However, the odour tends to dissipate with incorporation of the material into the soil, and Best Management Practices include rapid incorporation.


In sum, while the literature does not clearly identify health hazards from land application of biosolids, it also doesn’t generate a feeling of complete ease.  At this point, the research is inconclusive. Given the benefits of land application and a lack of compelling evidence of risk, it would be alarmist to stop land application in Ottawa now.  However, to minimize any potential risk, more conservative practices and annual reviews are necessary.

Best Management Practices (BMPs)


Most Best Management Practices listed in the report exceed current provincial standards or create a new practice.  The goal of implementing best practices is to protect health, to adapt a more cautionary approach than what is suggested in provincial guidelines, and to improve communication with the public.


These goals will be realized by:


·        Limiting public exposure of biosolids

·        Placing more restrictions on biosolids use

·        Providing detailed instructions on procedures

·        Improving testing, monitoring and training

·        Implementing a comprehensive approach

·        Better information-sharing


Several of the proposals are already being practiced in Ottawa and should continue. These include well monitoring and nearby resident notification.  Other proposals, such as caution signs around fields, more detailed complaint protocols, and rapid incorporation of biosolids into soil represent more significant changes to the City’s program.  If adapted, these best practices would be considered among the most stringent in North America.


Of the 27 farm sites spread last year in Ottawa, there was one documented health complaint – members of a family living close to a biosolids stockpile complained of diarrhea, headaches, dry eyes and dry throat.  After investigating the matter, Public Health identified no health hazard. Results of the City’s well testing and stool sampling were negative.  Nevertheless, the complaint did raise concerns about the proximity of stockpiles to neighbouring residents.  The proposed Best Management Practices address two issues here.  First, unlike provincial guidelines, the Practices specify separation distances from stockpiles to residences and population centres.  Second, they institute a formal complaint process.


Limiting Public Exposure


Current provincial guidelines restrict biosolids spreading to within 50-450 metres from a residential area.  (A residential area is defined as seven or more adjacent residences on 1.5 acres maximum lots).  However, the BMPs maintain a separation distance of at least 450 meters for residential areas and other places such as schools, multiunit residences, retirement homes and centres of employment.  Separation from a well is at least 90 metres in the BMPs, whereas current provincial guidelines allow for a separation distance of 15-90 metres, depending on the well type.  BMPs propose that stockpiles, which are not addressed in the province’s guidelines, should be located at least 450 m from an individual residence.  Hauling trucks need to be inspected and tarped. Biosolids inadvertently tracked onto public roadways should be removed immediately.

Placing More Restrictions


According to the proposed best practices, farmers should wait at least one year after biosolids application before growing non-root vegetable crops, five years before growing root vegetable crops, and five years before using the land as pasture.  The provincial guidelines are weaker, allowing for pastureland after only two to six months.  The BMPs prohibit application in areas subjected to frequent flooding and during times of disruptive wind conditions – two problems not addressed by the provincial guidelines.  Incorporating (mixing) biosolids into the soil should be done within two hours of application rather than allowing 24 hours.


More Detailed Procedures


The Best Management Practices explain how soil depth and field size should be measured, what should be included in a site plan.  Protocols responding to complaints, well contamination, public health incidents, spills and violations are covered in the BMPs, but not addressed in the provincial guidelines.


Improved Testing/Monitoring/Training


While not required by the Province, site inspection by a qualified party, independent of the contractor, is included as a BMP.  Monitoring the quality of pre-application biosolids should be done every two weeks, somewhat more frequently than what the Province suggests.  The BMPs also require testing of wells before and after biosolids application, and soil pH testing within four months prior to spreading.  The BMPs provide direction on how and when to measure soil depth.  Training of staff and contractors is also included.


A Comprehensive Approach


Controlling pollutants entering the waste treatment plant is an important part of the biosolids program.  Two programs are already in place - The City’s current “Take It Back” program for unused medications, and continuing efforts to strengthen the Industrial Sewer Use Control program.


Better Information Sharing


Currently, the landowner signs an application form simply indicating consent.  The BMP involves a more detailed consent, indicating a full understanding of crop restrictions, waiting periods, site plans and nutrient amounts.  Where the landowner differs from the farm operator, the farm operator must also sign the consent.  Under BMPs, residents within 450 metres of the spreading site are notified between two to eight weeks before spreading.  Information about the biosolids program should be made easily available for public inspection, and signs indicating the use of biosolids need to be posted around fields. None of the above practices exists under provincial guidelines.

If Council approves the above practices, the City’s biosolids land application program will begin immediately by implementing all the health-related BMPs as well as practices regarding separation distances and incorporation.  BMPs already in place will continue.  All efforts will be made for the remainder of BMPs to be implemented within four to six weeks of Council approval.





The issue is of concern to all residents of Ottawa, but particularly to those who live in rural areas. Rural residents live closest to lands applied with biosolids, and farmers use biosolids as a fertilizer alternative for their crops.





The Biosolids Management Plan Update (2001) involved extensive public consultation, giving Ottawa residents many opportunities to provide input.  There were two open houses, followed by a workshop and a public meeting, then an extended period of public input after release of the plan, which was made available through client service centers and rural libraries.  The Biosolids Management Plan Update Public Advisory Committee met six times.  The Medical Officer of Health also met with the community group Health Dangers of Urban Use of Pesticides (HDUUP) in Dec. 2001 to discuss the biosolids issue. Public input received from the above sessions was considered in the preparation of this report to Committee.  Prescribed time constraints did not allow for new consultations.


Ongoing efforts are underway to better interact with the public to respond to the community’s needs.  Examples of these efforts include development of an electronic registry for biosolids complaints that will be made accessible to the public, and the initiation of a pilot Biosolids Environmental Management System that incorporates significant public input.


The project methodology was presented to the Environmental Advisory Committee on March 14.  A presentation scheduled for the Agricultural and Rural Affairs Advisory Committee on March 26 was cancelled on account of inclement weather.





The Best Management Practices recommended by the Medical Officer of Health, in consultation with TUPW and other experts, will increase the program operating costs of the Utilities Branch of TUPW.  It is expected that an additional $100,000 in operating costs will result in the areas of enforcement, site selection procedures (investigation, assessment and review), and documentation/information management.  This amount was not identified in the 2002 operating budget, TUPW will try to accommodate the increased cost.  TUPW will identify this amount as a 2003 budget pressure.




Document 1 – Executive Summary, Health Aspects of Biosolids Land Application

                        (Full report on file with the City Clerk.)





TUPW staff will move to implement all health-related BMPs immediately, as well as practices regarding separation distances and incorporation.  Every effort will be made to implement all other BMPs within four to six weeks after spreading begins.


TUPW staff will resume land application of biosolids with their contractors.

Document 1

Health Aspects of Biosolids Land Application


Prepared for

City of Ottawa

March 2002




Prepared under the direction of the Medical Officer of Health by:

Erik Apedaile, P.Ag.

Environmental Management Services

1622 Pullen Ave

Ottawa, Ontario

K1G 0N7


CH2M HILL Canada Limited
1101 Prince of Wales Drive

Suite 330

Ottawa, Ontario

K2C 3W7


Dr. Donald Cole, M.D.

Department of Public Health Sciences

Faculty of Medicine

University of Toronto

12 Queen’s Park Crescent West

Toronto, Ontario

M5S 1A8

University of Toronto

Department of Public Health Sciences

Faculty of Medicine, McMurrich Building

12 Queen’s Park Cres West

Toronto, Ontario  M5S 1B8

Tel 416/946-7870  Fax  416/ 978-8299




1 April, 2002





Dr. Robert Cushman

Medical Officer of Health

City of Ottawa

495 Richmond Road

Ottawa, ON 



Health Aspects of Biosolids Land Application


Dear Dr. Cushman:

Based on the information collected in the report “Health Aspects of Biosolids Land Application” (March 2002), as a qualified community medicine specialist and independent reviewer, I support your recommendation to continue with the practice of biosolids land application. 

I am making this recommendation in the context of the implementation of the Best Management Practices by the City of Ottawa.

Yours truly,


Dr. Donald Cole, M.D., M.Sc., FRCPC
Associate Professor

Executive Summary


Built in 1961, the Robert O. Pickard Environmental Centre (ROPEC) is one of the largest wastewater treatment facilities in Canada. The facility treats an average capacity of 545 million litres of wastewater per day, with a peak capacity of 1,362 ml/d. It produces about 30 dry tonnes of dewatered biosolids (approximately 4 truck loads) per day.


In August 2000, the City initiated its five-year update of the Biosolid Management Plan.  The update included a comprehensive review of current practices, identification and assessment of alternatives, and extensive public consultation. The update was based on the premise that the Province of Ontario is responsible for regulating biosolids for protecting public health.


In December 2001, while accepting the recommendations of the Biosolids Management Plan Update, Ottawa City Council directed the Medical Officer of Health (MOH) to review the safety of land-applying biosolids and to develop application standards that meet or exceed the current provincial standards. Specifically, the MOH was directed to take the following actions:


·        Retain the necessary experts to conduct a scientific review of the safety of spreading biosolids

·        Recommend interim best management practices for the City’s biosolids management program

·        Present the expert analysis and the new standards to the Environmental Services Committee


The biosolids land application program for Ottawa was suspended pending the outcome of the MOH’s recommendation.




In response to Council’s directive, the MOH retained Apedaile Environmental and CH2M HILL Canada Limited to undertake the following:


Task 1:       Search, collect, and summarize the current literature on health aspects of land-applying anaerobically digested, dewatered biosolids


Task 2:       Interview specialists to provide scientific and regulatory perspectives on current work in the biosolids area


Task 3:       Develop interim best-management practices based on current practices, research, and experience


The Medical Officer of Health elected to undertake a 4th Task: 


Task 4:       The City was to retain a qualified third-party health specialist for evaluating the information and providing feed back to the MOH


The project team recognizes that the issue of human health related to land application of biosolids is of general public concern and, while there is a great deal of literature related to this topic, there also is much disagreement.


Every attempt has been made to reflect views from across the spectrum on this issue. The intent of this report was to identify the research and information available for the sole use of the Medical Officer of Health in his determination regarding the safety of land application of biosolids for the City of Ottawa.  The opinions and views expressed in the literature and in interviews are those of the authors and interviewees and not of the City or its consultants.




The project focused on collecting health-related information bearing on the type of biosolids generated at the Pickard Centre and on its land-application practices. The project team collected scientific literature and abstracts, and spoke with a series of key contacts and specialists in the field of biosolids management related to human health issues.


During the review two key difficulties emerged:


1.                  There is a lack of multi-disciplinary research and biosolids-specific medical data


2.                  The vast body of research related to biosolids and land application required a narrowed field of focus given the time constraints of this project


To narrow its focus, the team used a recently published review of literature and stakeholder groups as a starting point for collecting scientific literature. This review, Fate and Significance of Selected Contaminants in Sewage Biosolids Applied to Agricultural Land Through Literature Review and Consultation with Stakeholder Groups (April 2001) was commissioned by the Water Environment Association of Ontario (WEAO). The WEAO review examined a broad range of contaminants and divided them into two groups:


Group I contaminants: These have sufficient, credible scientific evidence to demonstrate that they are not a concern in sewage biosolids

Group II contaminants: These do not have sufficient, credible scientific evidence to demonstrate they are not a concern in sewage biosolids

Therefore, the team focused on the Group II contaminants, namely:


·        Pathogens

·        Unregulated metals

·        Estrogenic hormones and pharmaceutically active compounds


The team also explored emerging issues (PBDEs and health effects related to odours) and health studies.  An overview of the literature in these areas is presented in this review, however, as the WEAO studied noted, all of these areas are in need of further research. The review team developed a database of the literature considered in preparing this report, and collected and collated hard copies of the majority of the literature.


Key contacts and specialists were selected to represent the breadth of scientific and regulatory opinion on health aspects of biosolids land application. People involved in developing and implementing regulations in the United States and Canada, as well as people from research institutions who have been critical of the regulations were selected for interviews. In addition, published researchers were contacted for context and clarification of their published work. The ability to interview key contacts and specialists was limited by time and budget.


The literature and interviews with key contacts and specialists assisted in the development of a series of interim best management practices (BMPs). One premise used to develop the interim BMPs was that limiting public contact with biosolids may mitigate potential public health risks from exposure.  In addition, the BMPs sought to respond to community concerns specific to the City of Ottawa identified during the Biosolids Management Plan Update public consultation process.  The interim BMPs cover all aspects of the land application program from selecting application sites, the approval process, and spreading activities, to record keeping and auditing. Emergency measures and at-source controls also are addressed.


Finally, in accordance with Task 4, a qualified and independent third party, Dr. Donald Cole, MD, an expert in community medicine with the University of Toronto, was retained directly by the Medical Officer of Health.  Dr. Cole assessed the information collected in Tasks 1-3 and provided feedback to the MOH in his determination regarding the safety of biosolids land application.