composting options at trent university: exploring environmental impact prevention & monitoring...

8/9/2019 Composting Options at Trent University: Exploring Environmental Impact Prevention & Monitoring Systems

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Composting Options at Trent UniversityExploring Environmental Impact Prevention & Monitoring Systems

Report Prepared for Trent Universitys Office of Sustainability and

ERST-3080: Waste Management, Trent University

Report Prepared by: Chris Ferguson-Martin


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March 22, 2010

Introduction

Several years ago, Trent University identified its waste management and waste diversionprograms as areas that needed to be vastly expanded and improved. In addition to a

significant expansion of its recycling program, Trent began a composting program to

collect compostable materials from locations on campus, primarily in the schools

cafeteria. Because Peterborough does not have a municipal composting program, Trent

elected to manage, process and store the compost on site.

Despite having stored the compost on site for a few years, Ontarios Ministry of the

Environment (MOE) only recently came to evaluate the site. Based on the visit from the

MOE, Trent was asked to develop a system that prevents and/or monitors potential

impacts.

The purpose of this report is to outline in detail the options available to Trent

Universitys composting site. It looks at the financial, environmental, regulatory and

pragmatic factors that are taken into consideration with each option. The report also

provides a general review of the composting program at Trent University.

This report serves a purpose for three separate organizations. First, it is a coursework

project in ERST-3080, an undergraduate waste management course at Trent University. It

is also designed specifically for Trent Universitys Sustainability Co-ordinator, Shelly

Strain and indirectly for the MOE.

Trents Composting Program

In 2005, the City of Peterborough proposed a pilot composting program that would

primarily involve the creation of a major commercial composting site (EAB, 2005).

Theoretically, compostable material (organic material) would eventually be collected

from commercial businesses, institutions and residences and processed in a centralized

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facility and later sold to consumers of high quality compost. More importantly, the

program would divert huge sums of compostable material out of the traditional waste

stream.

Trent University, seeing its own student-run compostable waste program from food

services capturing the relatively small amount of 1000 kg of compostable material each

year contacted the City of Peterborough to be a significant part of its new pilot compost

program (EAB, 2005). But because the program was still in its infancy, Trents immense

size prevented it from being included in the early stages of the program. Indeed, the City

of Peterboroughs curbside compost collection program has been faced with numerous

delays. Approval for the construction of a composting facility is not expected until 2011,

indicating a considerable length of time will come to pass until a major composting

program is put into place (City of Peterborough, 2010).

Figure 1: Birdseye view of Trent Universitys Compost Facility

While Trent was not able to align itself with the citys program, it elected to increase the

scope of its own composting program. In 2005 a central composting site was established

on the south end of the campus in the Commoner parking lot, a 2,500 m2 unpaved space

situated just west of Nassau Mills Road. The site is accessible by a small unpaved road

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and nestled in behind a slightly forested area. Importantly, the site is also adjacent to the

nearby Trent-Severn Waterway, a large navigable waterway.

Trents composting program has grown considerably since its relatively humble

beginnings in 2005 when only 1000 kg of compostable material was collected. Compost

collection bins were introduced first throughout Trents food facilities and cafeterias in

2006 and throughout much of the campus in later years. The effects were felt remarkably

quickly. During the 2006-2007 school year, 15,000 kg of compostable waste was

collected, a 15 fold increase (Arthur and Shah, 2009). The composting program was

further extended when in 2007, Trent hired a full-time Sustainability Coordinator

whose mandate included improvements to waste management and comprehensive

Resource Recovery Stations (RRS) were built throughout campus. An RRS contains one

or more composting bins, several recycling bins and a waste bin.

The implementation of a Sustainability Coordinator, along with the assistance of on-

campus student groups certainly helped to catalyze Trents composting program. In the

2007-2008 school year, compost collection amounted to 56,000 kg, a 273% increase in

one year (Arthur and Shah, 2009).

A campus wide survey completed in early 2009 found that while the composting program

was growing rapidly, the level of awareness at the school was seriously lacking among

students, staff and faculty (Arthur and Shah, 2009). However, it is expected that this

deficiency is primarily a result of the programs relative infancy and infancy of

composting in general. The university has continued to implement and is continually

working on strategies to increase the participation of people on campus in composting.

The compostable material collected when processed properly at the Commoner site

will be used by Trents Physical Resources Department as high quality, fertile soil in its

landscaping projects throughout campus. However, as the compost levels increase at

Trent, it is becoming increasingly attractive to sell the compost commercially. The report

created out of the aforementioned survey cited this as a current and future challenge for

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Trent as it has had difficulty finding commercial consumers of its compost. The report

predicted that once the City of Peterborough establishes its city-wide compost program,

the local compost sector will grow considerably in Trents favour. However, in

discussions with Trent staff, it is unlikely that Trent will ever produce more compost than

it consumes. Moreover, by selling compost commercially, the compost would be subject

to further regulations.

Considering the infancy and rapid growth of Trents compost program, especially in a

time where commercial composting is only beginning to develop, the impediments

regarding awareness of composting on campus should not overshadow the success of

such a program. However, as discussed in the following section, the next challenge for

Trents composting program has very little to do with on-campus awareness, but rather it

is regulatory in nature.

MOE Regulations & Problem for Trent University

Compostable material is waste. Although organic and other compostable waste has the

biological properties and potential to be turned into highly fertile compost, it is still

considered waste until being fully converted into compost. This is particularly

problematic of open-air composting sites, where organic waste is placed into systematic

piles in an open space. In these situations, the piles of organic waste placed outside are

generally unprotected, leaving them vulnerable to winds and rains. Some even liken it to

an open-air dump.

Because organic waste can still create biological hazards to the surrounding environment,

they typically require government permits in order to operate legally. Trent has run into

this problem. Its central composting site places the compost in systematic piles

throughout the lot, in open air and without protection. This is known as a windrow

system. Upon visitation from Ontarios Ministry of the Environment (MOE) in the fall of

2009, Trents composting site was evaluated for regulatory reasons. Indeed, the MOE is

given jurisdiction over composting programs through Regulations 101 & 347 from Part V

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of theEnvironmental Protection Act. Luckily for Trent and quite fairly the MOE,

recognizing that Trent is only processing organic material generated on campus by the

Trent community, determined that Trent was not subject to permit requirements under

these regulations.

While not being subject to the permit requirements, risks related to the leachate from the

composting site still drew concern from the MOE. As a precaution to these risks, the

MOE directed Trent to explore a series of options that would provide protection from any

of the compostable material endangering the surrounding environment, most notably the

nearby water resources of the Trent Severn Waterway.

Given Trents inexperience in developing such protective systems, the MOE offered a

few general solutions including a liner system that could be built underneath the site.

Several months later, during another visit to the site, MOE officials also indicated that a

water-well testing system would also be an option Trent could visit.

Below, these options are explored with a variety of criterion in order to provide Trent

with the information required to properly satisfy the concerns presented by the MOE.

Solutions

In this section, several options are proposed Trents compost site: simple liner system;

advanced liner system; in-vessel system; a water-well testing system; and a contained

structure add-on. The different options available for Trent are evaluated using the

following criteria: cost, environmental effectiveness, maintainability, durability and

longevity.

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Simple Liner System (SLS or Compost Pad)

Figure 2: A concrete pad used at Washington State University

The simplicity of an SLS is that it is only made up of one or two materials and has no

working systems within it, such as pipes or pumps. The three most common materials

used for such a system are asphalt, concrete or compacted clay with a thickness of at least

0.5 metres. All three materials are strong and have low permeability levels, although it is

recommended that the material used not have a permeability rate higher than 5x10-8 m/s

(Brent Hansen Environmental, 2004).

Additionally, a combination of filter fabric and gravel or sand can be used. The fabric,

such as a strong, agriculture-grade cloth, is placed over the area of the site and layered

with several feet of crushed gravel. The fabric captures any leachate and prevents the

gravel from sinking into the ground. Moreover, the gravel provides a relatively solid

surface for storing the compost and accommodating equipment (Cornell Waste

Management Institute, 2005).

When implementing an SLS, four important factors must be taken into consideration

(drawn from Brent Hanson Environmental 2004):

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1. The base has to provide a barrier to prevent the percolation of leachate and/or

nutrients to the sub-soil and groundwater.

2. The surface has to accommodate equipment movement during wet weather and

working conditions.

3. The surface area has to accommodate the maximum annual volume of feedstock

received with sufficient room for equipment to manoeuvre and an area to establish

a static pile for curing compost.

4. The surface area has to drain to a leachate collection system that can provide a

source of moisture to be re-introduced into the processing windrows. In order to

ensure proper draining, the surface should have a minimum slope of 2%.

Cost: The costs for such a system can vary depending on the material used. For poured

materials such as concrete or asphalt, costs are estimated at approximately $150-$200/m3

and assuming a thickness of 0.2 metres, the total cost of building on the current site

would be between $78,000 and $100,000 (Brent Hansen Environmental, 2004). Costs for

a thicker (~0.4 m) compacted clay pad are very similar. This report does recognize,

however, that Trent already has significant experience building such projects and may

have more accurate figures.

The costs of a fabric and gravel system are considerably lower at approximately half the

cost of a poured project. For assurance on cost estimates, please contact your local

contractor.

Environmental Effectiveness: SLSs can be very effective in preventing soil or

groundwater prevention, but because they are simple and usually quite inflexible,

managing runoff can be difficult, which is especially important in Trents case because of

the sites proximity to the river. They also do not prevent wind or rain impacts.

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Maintainability: Poured systems can be easy to maintain because they are so simple.

Moreover, repairs done to concrete or asphalt can generally be made simply by displacing

compost piles and repairing the pad from the surface. Fabric and gravel systems can more

difficult to maintain because the liner is buried under several inches of gravel.

Durability & Longevity: Poured systems are extremely durable and long-lasting. They

can accommodate a considerably high amount of weight. A concern frequently

mentioned by experts in the waste management sector is the use of the site after the

compost system ceases to function. Poured systems are very difficult and expensive to

remove completely from a site, so the permanency of the site as a compost facility should

be considered. However, a poured system can be later used as the foundation for any later

projects, including parking lots or buildings.

A fabric and gravel system is not as durable or smooth as a poured system. But since

Trent does not use huge amounts of heavy equipment, it might be suitable. With such a

system you also need not worry about the permanency mentioned above.

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Advanced Liner System (ALS)

Figure 3: Cross Section of an ALS

Advanced liner systems are predominantly used for very large and complex compost

projects and are commonly used in engineered landfills. The scope of Trents site is

likely well short of requiring such a complex system, so it will only be explored in a basic

fashion.

As opposed to an SLS, an ALS contains several layers of materials, including synthetic

geomembranes and highly compacted clay. Moreover, leachate collection pipes are often

installed as part of the layers. Similar considerations to an SLS should be taken, although

the weight held by such systems would be much greater in the case of an ALS.

Cost: Such systems can vary in cost depending on the complexity of the system, but an

estimate for the size of Trents site would be ~ $143,000 (Munie, 2003).

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Environmental Effectiveness: An ALS system is one of the most effective forms of

environmental protection in waste management. Indeed, they are designed to deal with

traditional waste streams from landfills. Since Trents site primarily deals with relatively

low levels of organic waste, an ALS is likely more effective than it needs to be.

Maintainability: Such a complex system is also very difficult and expensive to maintain.

Multiple layers make it extremely difficult to repair any tears or cracks. Moreover, the

piping system, which is likely to erode faster than other materials, is extremely difficult

to access because of the immense weight over top of it.

Durability & Longevity: Because of its complexity, different parts of the system last

longer than others. However, as a whole, the system is more durable than other systems

because of the added layers of protection. Of course, the effectiveness of the system

degrades quickly as parts of the system fall apart.

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In-Vessel (IV) or Containerization

Figure 4: In-vessel composting system, University of British Columbia

An alternative approach to dealing with Trents compost issue is to implement an in-

vessel system. An IV system involves placing the collected material in a container as

opposed to the lying it on the ground. This reduces the risk of leachate contaminating the

surrounding area and reduces the time required for high quality compost to be created.

Although several forms of IV systems exist, the most common and most applicable to

Trents situation is a rotating drum system. The collected material is placed into a large

drum made from corrosion-resistant metal or high grade plastic that is rotated very

slowly (~1 rpm) by a small motor. The container has holes for proper ventilation and any

leachate is collected and drained from the drum. After composting inside the container,

the material is placed outside to cure for several days, weeks or months depending on the

need (R. W. Beck, 2006).

It is important to note that in order to introduce an IV system at Trent, some of the

aspects of an SLS would also need to be implemented. First, a concrete or asphalt pad of

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some kind would need to be built for the drum to sit on. Moreover, an SLS of some kind

would have to be built to store the curing compost. However, despite these needs, the size

of the SLS would be considerably smaller because less land would be required as much

of the compost would be stored in the container.

IV rotating drum systems come in a variety of sizes and from several manufacturers.

Rotating drum systems are classified as either mobile or stationary units. Typically,

stationary units are considerably larger and permanent, while mobile units are smaller

and can be moved around a site very easily. Mobile units are particularly popular in

agricultural settings where sites are extremely large but total collected material is

relatively small (R. W. Beck, 2006). An appropriate size and type of system for Trent

would very much depend on expected compost collection levels and a market to sell or

use the more quickly generated compost.

Compared to Trents current system, an IV system carries several benefits. The process is

more controlled and allows for greater control over odours, gases and leachate. The

system requires a much smaller area and the compost turnover time can be drastically

shorter some manufacturers claim a turnover period of only one week. Moreover,

because a motor runs the system, there are less operational obligations on the part of staff

(R. W. Beck, 2006).

Cost: The cost of such a system largely depends on the size of the drum used. For drums

appropriate to the size of Trents site, the upfront capital cost of a rotating drum can

range from as low as $80,000 to as high as $250,000 (R. W. Beck, 2006). An SLS will

also need to be built, which could range in cost from $30,000 - $60,000. It is important to

note that because the compost can be processed considerably faster, more of it can be

sold or used by Trent for landscaping purposes.

Environmental Effectiveness: Because the system is contained, leachate and other

environmental concerns are much easier for operators to control. Moreover, by placing

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the compost in the container, it removes much of the leachate risk as compared to the

typical windrow system.

Maintainability: An IV system is easily maintainable because it is above ground, easily

accessible and contains relatively few parts. The container is large enough to work with

and the small motor is like any other small motor. However, because it does use

machinery, it may require maintenance more often than an SLS system.

Durability & Longevity: A major concern with storing compostable material indoors is its

tendency to corrode the surface containing it. Almost all IV systems are made from

specially coated, corrosion-resistant materials that can handle significant weight.

Moreover, the IV drums tend to last at least twenty years, although the electric motors

might need to be replaced in lesser time in order to ensure efficiency.

Roof Structure (add-on)

Figure 5: Compost storage building, British Columbia

One factor that contributes to leachate and runoff is rain. Open windrow systems, like

Trents, are particularly susceptible to rain because they are uncovered. Without any

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other protective systems like an SLS, rain poses a significant risk of soil contamination

and contamination of nearby water resources from runoff. A strategy to mitigate such risk

would be to build a canopy structure that places a roof over the composting material.

The complexity of such a system can range from a simple fabric roof which is no more

than $5,000 to a steel containment structure that could cost as much as $50,000 (WRS

Cover-All, 2010). Building a roof structure might limit expansion of the site and would

require an additional diversion system to guide the rainwater away from the composting

material.

A roof structure is also used by some IV systems as a means to protect it from the

elements. If one is built with walls, wind erosion could also be mitigated, which is

important as wind can shift around piles of compost.

As noted above, such a structure would simply be an add-on to the aforementioned

systems. It by itself would not suffice to meet the MOEs criteria, but could have a

significantly beneficial environmental impact.

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Water Well Testing

Figure 6: Test water well, Oklahoma

One of the options put forward by the MOE was to build test water wells as a means to

monitor the impact of the compost site on the water resources located nearby. While this

option is much easier to implement than any of the above systems, it does little to prevent

leachate or any other contaminants from getting into the water system. The main problem

is that if it does detect contaminants, a preventative system might have to be built anyway

after some damage has already been done to the environment.

Although by itself this strategy might satisfy MOE concerns, this report recommends that

if water well testing is implemented, it be implemented as a complement to a preventative

system. Indeed, the risk of contamination from the current system especially if

compostable material collection is expected to grow is too great to simply monitor the

risk but do nothing to prevent it. However, even when preventative measures are put in

place it is extremely important to monitor the impact of those measures to ensure their

effectiveness.

Cost: The inclusive cost of digging and building the wells, in addition to having them

tested would be no more than a few thousand dollars. Indeed, Trent has the resources to

test the wells on its own and water well testing is a fairly standard practice.

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Environmental Effectiveness: Water well testing is effective at measuring the impact of

the site on the surrounding environment, but does nothing to prevent or mitigate that

impact.

Maintainability: Test water wells are very easy to maintain as they are not as complex as

drinking water wells and are generally made from simple but strong materials. Moreover,

they are so common that many people can easily maintain them.

Durability & Longevity: Test water wells are made from extremely durable materials and

can last several decades.

Options Evaluation by Criteria Criteria

Cost

Environmental

Effectiveness Maintainability Durability Longevity Poured

SLS High Medium Medium High High Option Fabric SLS Medium Medium Medium Medium Medium

ALS

Very

High High Low Medium Low

In-Vessel

Very

High Medium High High Medium Test Water

Well Low Low High High

Very

High

Figure 7: Options Evaluation by Criteria

Comparison to other Universities

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Because Trent is a university, it has characteristics that differentiate it from a typical

composting program, such as one run by a municipality: its source of funding is different;

collection is primarily on-site; and universities often have a wealth of enthusiastic,

energetic volunteers and student groups to help run the program. Throughout this project,

several universities were contacted that have composting programs in order to compare

their strategies, particularly relating to the implementation of an environmental control

system like those explored above.

The majority of schools contacted have placed their composting operations on a concrete

pad. According to a member of McGill Universitys staff, a concrete pad is fairly

standard practice. It should be noted that Trent is among the smallest of universities in

Canada and is certainly one of the smallest implementing an on-site campus facility. This

is a particularly important point because the resources available and the scope of the

composting programs are considerably different at other schools. For example, many

schools, particularly the University of British Columbia and McGill, have not

encountered the same problem Trent has because they invested in in-vessel systems and

did not place additional compost on unpaved lots. Moreover, when implementing their

programs, several of the schools placed the facility on otherwise unused, paved lots.

A list of schools with links to their composting sites can be found at:

http://gorilla.mcgill.ca/resources.htm

Conclusion

I should first be clear that in no way does this report set out to define Trents priorities,

but rather to provide Trent with the necessary information to make an informed decision.

Trents situation with the MOE appears to be one that very few other universities have

encountered, but it is one that is easily repairable. Because the implied standards given to

Trent by the MOE might require only as much as a water well testing system, this might

suffice depending on Trents own inclinations. However, it is in the opinion of this report

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that given the strategies of other schools and the non-preventative nature of a water well

testing system, Trent should implement a system in addition to water well testing.

Because a concrete pad is fairly standard practice and the location will likely be used for

many years to come, it might be the most appropriate option. However, a fabric and

gravel liner system might also prove appropriate to Trents situation. An in-vessel

system, depending on the size, might prove financially prohibitive given the amount of

compost collected on a daily basis and an ALS seems far too complex for the nature of

Trents site.

Regardless of the prevention tool of choice, I strongly recommend that a preventative

system be put in place, especially before the composting program (and site) at Trent

grows.

References

Visual Resources

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Figure 1: Google Maps

Figure 2: http://organic.tfrec.wsu.edu/compost/Other%20management/Rynk%2088mid.jpg

Figure 3: https://reader010.{domain}/reader010/html5/0601/5b107f0076bcc/5b107f09df6a0.jpg

Figure 4: www.recycle.ubc.ca/compostmain.htm

Figure 5:http://www.wrscoverall.com/CustomerProfilePix/CompostStorage/Compost2.jpg

Figure 6: http://www.ok.gov/mines/images/Water%20Well%20on%20Ash%20Site.jpg
http://organic.tfrec.wsu.edu/compost/Other%20management/Rynk%2088mid.jpghttp://organic.tfrec.wsu.edu/compost/Other%20management/Rynk%2088mid.jpghttp://seccra.org/storage/thumbnails/3521091-4017070-thumbnail.jpghttp://www.recycle.ubc.ca/compostmain.htmhttp://www.wrscoverall.com/CustomerProfilePix/CompostStorage/Compost2.jpghttp://www.ok.gov/mines/images/Water%20Well%20on%20Ash%20Site.jpghttp://organic.tfrec.wsu.edu/compost/Other%20management/Rynk%2088mid.jpghttp://organic.tfrec.wsu.edu/compost/Other%20management/Rynk%2088mid.jpghttp://seccra.org/storage/thumbnails/3521091-4017070-thumbnail.jpghttp://www.recycle.ubc.ca/compostmain.htmhttp://www.wrscoverall.com/CustomerProfilePix/CompostStorage/Compost2.jpghttp://www.ok.gov/mines/images/Water%20Well%20on%20Ash%20Site.jpg

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