Environmental Engineering
This page outlines my consulting work in environmental engineering. I also describe some of the projects I have completed or that I am currently working on.
Consulting Environmental Engineering Services
My consulting environmental engineering work includes:
| A. | Contaminated site investigation and assessment of the extent of contamination and identification of the source and cause of a release of pollutants into the environment. |  |
| B. | Designing remediation of contaminated sites and implementing clean-up. | |
| C. | Carrying out Phase I and II Environmental Site Assessments (ESAs). (The ESA assessments are carried out according to the requirements of the Canadian Standards Association (CSA) and their periodic updates) | |
| D. | Carrying out environmental impact assessments (EIAs) of sites proposed for development and construction of buildings and civil engineering structures. |
Guidelines are given on the Guidelines Page for some of the key tasks that I carry out when practicing environmental engineering)
Examples of Environmental Engineering Projects
Each project is briefly described, significant problems identified where found, and the method of investigating the problem outlined.
I personally carried out the environmental engineering investigations following the steps outlined in the Guidelines where applicable. Drilling and excavating work was contracted out to local firms. Laboratory testing was carried out at commercial laboratories in the area.
I did independent research on the cost control of projects that highlighted the importance of first defining the problem before trying to fix it and, second, ensuring experienced engineers are on site to direct the fixing – see below, 1. Research Clean-up Costs.
I surveyed 11 environmental clean-up contractors and insurers about the cost of cleaning up sites contaminated by an oil spill. The cost of these clean-ups is usually borne by an insurance company. I decided to carry out this research when I chanced to learn that clean-up costs may be higher than they need to be, a lot higher in some cases.
My research found that at least 25% to 35%, possibly more than half, of all oil spill claims in Nova Scotia are costing insurance firms at least 50% more than they should. Twice as much is not unusual. Horror stories exist of oil spill remediation costing several times what they should – I calculated 3.8 times as much, 4.6 times and 6.0 times for three oil spills using data supplied by the contracting firms.
The most frequently cited reasons for the cost over-runs were:
- Inexperienced site personnel representing the insurance firm (junior engineer, technologist, student, adjuster),
- Inadequate investigation of subsurface soil conditions and delineation of the problem - the location of the plume of contamination
- Poor planning and organizing of the work by the site representative.
During my survey the owners of the contracting firms advised me of final costs to the insurance firms for a number of clean-up contracts. The costs varied from $10,000 to $500,000, but typically from $100,000 to $250,000 per clean-up. In every job mentioned by the contractors during the survey the cost to the insurance firm could have been less, and, as indicated above, significantly less.
There are many dozens of contaminated site clean-ups carried out in eastern Canada each year.
The majority of the contracting firms operated in the Halifax area, two were outside this area but on the mainland and one was in Cape Breton. I met with the owner of each firm for typically 1.5 hours and went through a list of questions I had prepared beforehand to guide me during the interview. The owners were quite forthcoming and candid in their remarks in exchange for my assurance of confidentiality.
2. Furnance Oil Spill, Whitney Pier, Cape Breton Island
A 30-year old, steel furnace oil tank for a modest home finally corroded through and spilled approximately 100 gallons of fuel oil on the ground adjacent the basement walls. The spill was detected when the owner’s furnace would not start.
The owner’s insurance company directed me to the property a day after the spill took place. Earthworks’ contractors had arrived a day earlier ahead of a snowstorm and had begun to excavate the contaminated soil under the direction of an insurance adjuster.
The home was situated on a semi-rural property where 45 cars had been abandoned, a few hundred metres uphill of a wetland. The owner did auto body repair work from a garage near his home.
I stopped the excavating work and investigated the extent of the contamination with exploratory holes, monitoring wells, soil and ground water sampling and testing. The results of this work was analysed and interpreted with respect to a study of the soil and bedrock geology of the area. I concluded that the furnace oil had not migrated off the property to nearby wells and the wetland.
The property was underlain by a layer of soil resting on jointed sandstone bedrock at a depth of eight feet. The water table was near the bedrock surface.
Remediation involved excavating the contaminated soil to clean boundaries determined by frequent soil sampling and laboratory testing. It was suspected that free product had perched on the water table. Groundwater was treated for a brief time until it was certain that the groundwater had not been contaminated.
It was necessary to underpin half the house foundations so the contaminated soil below could be excavated. Underpinning also involved rebuilding a weak, concrete block basement wall.
Special problems during remediation of this property were:
- A particularly hard winter in which to carry out the work,
- A difficult owner,
- Suicide of the owner’s son on the property during the work, one of the parties involved in the clean-up negotiations,
- Intimidation of the neighbours by the owner, neigbours who were downhill of the property (down gradient on the water table) and had to be involved,
- Contractors who, while pleasant and hard working, took every opportunity to inflate the work, and
- The underpinning of the house, a particularly skillful and critical type of construction work.
The final cost of the remediation was about half a million dollars, about 11.5 times the $43,000 market value of the house. The cost would have been considerably higher if full time engineering supervision was not present on site (see Research below).
A home owner’s furnace oil tank corroded through and leaked oil into the soil backfilled against the basement wall, ultimately seeping under the concrete basement floor.
The home was located adjacent the tar ponds in Sydney.
I investigated the extent of the contamination by coring holes in the basement floor and sampling and testing the underlying soil and groundwater. The soil was sampled and tested at increasing depth below the floor and a depth-profile of contamination determined. This showed how deep remediation had to extend below the floor, and how far into the basement. Contamination decreased with depth and with distance from the source of the spill.
Remediation involved excavating the soil within the plume of contamination and disposing of it off the property. The work was stopped once clean boundaries were reached and the concrete basement floor recast.
The final cost of the remediation was about $75,000, 1.8 times the $42,000 market value of the house. Costs were lower than the clean-up at Whitney Pier, which was underway at the same time, because the work was inside the basement, contamination had not migrated and underpinning was not necessary.
4. Furnace Oil Spill, Darmouth
I was retained by the owner of an apartment building to take over clean-up of a furnace oil spill begun by another consultant.
The initial consultant had estimated clean-up costs that seemed very high to the owner. The cost estimate was based on limited technical data and the consultant’s limited knowledge, as it turned out, of the approximate physical properties of the impacted foundation soils.
It is common knowledge amongst experienced, appropriately trained engineers that liquids, e.g., furnace oil, drain slowly through the poorly draining, homogenous, silty sandy soils that underlay the building. The spill could not have migrated far through such soils, and there were no other pathways to facilitate migration. Clean-up should be simple and relatively inexpensive.
I had a contractor excavate a small amount of additional soil, sampled and tested the soils, confirmed that clean boundaries had been reached, and signed off on the clean-up - for a fraction of the initial cost estimate.
5. Fuel oil spill, CFB Cornwallis
I was retained by Defence Construction Limited to investigate a possible fuel oil spill at pumps at CFB Cornwallis, Nova Scotia.
The investigation was quite straightforward, moreso than many residential oil spills.
I installed several monitoring wells down gradient (essentially down hill) of the pumps, and one control well up-gradient. I sampled and tested the soils during construction of the wells and learned that the soils were clean.
I retained a hydrologist to design a detailed groundwater sampling and testing program and had this carried out for a year. The hydrologist was particularly well experienced in contaminant transport through porous media.
The year long sampling, testing and monitoring established that the soils and groundwater were clean and that spillage of oil at the pumps was in very small and localized. The monitoring wells were decommissioned and the site signed off.
I have completed a number of Phase I and II environmental site assessments (ESAs) over the years. These assessments are often done in connection with change of ownership of a property, decommissioning of a property, like an abandoned service station, or investigation of a potentially hazardous site.
The assessments follow engineering investigative guidelines set out in various manuals. The emphasis is on identifying the different layers of soil and rock underlying a site, establishing how surface and groundwater flow through these materials (groundwater hydrogeology), identifying the presence of hazardous materials in the soil and groundwater, and establishing how the contaminants have migrated throughout the site (contaminant hydrogeology).
The Canadian Standards Association (CSA) have taken these guidelines and standardized the procedures.
A Phase I ESA is a gathering together of existing data on a site, and assessing this data to arrive at a subjective assessment of the likelihood or otherwise that the site is contaminated.
Depending on the outcome of the Phase I and the interests of the parties involved a Phase II ESA, which gathers new data, might be carried out. A Phase II establishes beyond a reasonable doubt whether or not the site is contaminated and the source and extent of any contamination that is present. Data from a Phase II will enable remediation to be planned and started. Sometimes additional Phase II type investigation must be carried out if the site is complex.
7. Colp Cranberry Bog Environmental Impact Assessment
I carried out an environmental impact assessment (EIA) of a cranberry growing operation proposed for a 32 acre wetland in Shelburne County, Nova Scotia.
A cranberry growing operation involves constructing beds where the cranberries grow, in this case on a peat bog but on other sites on a layer of sand. The beds are enclosed by low dykes that retain the water used in the growing operation. Construction does alter the natural environment whether on a peat bog or a layer of sand.
An EIA assesses the environmental impact of the growing operation on the natural environment during initial construction and subsequent operation. An assessment in report form is reviewed by regulatory authorities in considering approving development. An EIA relies heavily on existing information, particularly terrain evaluation (see Civil Engineering Page).
My EIA of the wetland:
- Described the features of the development;
- Studied the regulatory framework, in this case, as this relates to various aspects of the wetland;
- Identified qualitatively the potential impacts of the growing operation on the wetland and surrounding area;
- Described the affected environment; the key environmental factors anticipated to be changed by the cranberry development;
- Predicted and quantified the anticipated impacts of the cranberry development on the key environmental factors;
- Assessed impact significance of the anticipated changes related to the proposed cranberry development;
- Identified and evaluated potential impact mitigation measures;
- Developed an environmental monitoring plan;
- Drafted and submitted a report on the EIA.
A difficult feature of this EIA was the developer’s plans to relocate a natural stream that crossed the wetland and interfered with optimum lay out of the cranberry beds. Regulatory authorities looked closely at this element of the development.
The cranberry growing operation was approved and cranberries are now growing and being harvested from the wetland yearly.
Civil, Geotechnical, Foundation and Environmental Engineers
Dartmouth, Nova Scotia, Canada
Sailboat image courtesy of J. Knoll.
