4.0 Research Methods

To establish how St. Paul's can implement a composting system our group focused on three main questions. Our research questions were mapped on our Research Method Flow Chart. Our three main questions are:

1) How does a composting program work at a similar residence, St. Jerome's College?

The information from St. Jerome's composting program has been used as a guideline for proposing a program for St. Paul's. The technical and managerial issuses of their composting program have provided wisdom that we can share with St. Paul's College. We accomplished this research by:

2) Is composting feasible at St. Paul's?

We wanted to know how much organic waste is produced in the St. Paul's cafeteria and how many composters would be needed. To answer this question, we :

3) Why hasn't St. Paul's implemented a composting program in the past?

To understand the barriers to a St. Paul's College composting program we investigated:

We felt the barriers to a compost program at St. Paul's College could be overcome. We used the information gained from St. Jeromes' and other sources to recommend an effective and effecient composting program for St. Paul's. Our recommendations consider all aspects of our research.

*see appendix 1 and 2 for interview questions


This chart represents the outline of our study. The yellow box represents the focus of this study; How can St. Paul's College implement a composting program? Our research questions are explained above in section 4.0: Research Methods. The responses to our questions are found in 5.0: Research Results.


Key Criteria

The effectiveness of a composting program at St. Paul's depends on:

Criteria Measurements

The criteria listed above can be measured by determining the amount of waste being composted and how well the composters are being managed. The amount of waste St. Paul's diverts from the landfill should be the amount of organic waste produced in the cafeteria. Through our study, we found the average amount of compostable materials to be 7600 Litres per year. If this amount of waste is reduced, it would mean there is adequate participation in the program. Participation can also be determined by judging the attitude towards composting of those involved in the program. In order to participate, awareness is a key issue. If the staff and students of St. Paul's College are aware of the composting program, it will also show there is effective organization.The organization of the program can also measured by amount of organic waste being composted, and the quality of compost produced. Proper management is also based on this criteria. The student managers of the composting program could be evaluated on a regular basis to determine their commitment to the program. If all of the key criteria are met, based on these measurements, the compost program at St. Paul's will be effective.


To answer our research question "Is composting still feasible at St. Paul's College?", we needed to know how much organic waste is being produced. This will also help us calculate the number of composters needed. We decided to conduct a mini-waste audit that would test the relevance of the the data collected in 1992. If the data from the previous waste audit proved to be consistent with our data collected in the mini-waste audit, we could use their numbers to calculate how many composters are needed. The following is a detailed explanation of our study method for our mini-waste audit:

Study Time Frame:

We examined a sample of days:Tuesday, Wednesday and Saturday, to compare the amount of organic waste collected with that obtained in the 1992 study. These days were based on the previous study's data according to the highest, middle and lowest days of amount of organic waste measured. We also chose days that were not holidays or special events because this would have altered the data.

Once we gathered the data it was compared to the 1992 study. We then determined if the data from the 1992 study was approximately the same with the data gathered in the mini-waste audit. Since the organic waste measurements fell within the range of +/- 2.484 standard deviations from the previous study's mean, we considered it reliable. This did not indicate that our study is statistically conclusive. lf both sets of data did not match, we would have considered the previous study invalid and not applicable.

Since St. Paul's cafeteria menu items have changed little in the past five years, the amount of organic waste has also remained relatively the same. This can also be atributed to the fact that the number of students living at St Paul's is the same as in the 1992 study. Since we have determined that the data in the 1992 study is reliable we no longer needed to conduct a larger three week audit.

Data Collected During study:

In order to determine the number of composters that will be required it was imperative that we collected the following data:

We gained our information from the following methods:

1) The kitchen staff collected the number of meals served per day by using numerical sheets as each students recieves his or her meal. At the end of the day the staff records the number of students that came through the servery during each meal period. Chef Ron at St. Paul's supplied us with the attendance record for the entire year (March 31, 1996 to March 28, 1997).

2) To ensure that data was accurate we completed the following tasks:

These precautions were taken to avoid the limitations and errors indicated by the group in 1992, such as participants placing the wrong items into the compost bins.

Collection of Compostables:

Data was be collected on Tuesday, Wednesday, and Saturday at the following meal times:

The organic waste collection bins were placed in the cafeteria, in the preperation area and in the dishwashing area. These locations were chosen because, according to the floor plans and flows of people and food, they were ideal spots to collect the most amount of organic waste. The residents were responsible for placing their organic waste into the compost bin located in the cafeteria. Those organics wastes that were missed by the students were put into the containers in the dishwashing area, by the part time dishwashers. The kitchen staff was responsible for the compostable materials generated in the preparation area and placed it in their compost bin.

Data Tabulation:

Once all of the compostables were in the appropriate bins, the data was obtained in the following manner:

1) The height of the compostables in the bin was measured using a ruler. This datum was used to calculate the volume of compostables using the following formula:

The diameter of the pails was measured, thus the volume of the pail was determined by the formula L*W*H. The diameter of the smaller bucket was 25 cm and 26 cm for the larger bucket.

2) The net weight of the compostable materials generated was measured. The weigh scale that was used was at a 0.1 kg accuracy. The weigh scale was borrowed from the ecology laboratory in the Environmental Studies building. First the weight of the empty pail was recorded. Then, all of the compost from the cafeteria and dishwashing area was put together and weighed. The pail containing the compostables was hung from the scale and the weight was recorded by a group member. The weight of the compost bin was subtracted from the weight of the compostables in the bin. This gave the true weight of compostables.

3) At the end of the day the buckets were emptied into the main dumpster.

4) Chef Ron provided the number of meals that are served weekly for the year. They collect this data for their yearly records, thus it was readily available. Also, we collected data on yearly attendance for the final study.

* The Statistical Analysis of this study are discussed in section 5.2 Statistical Analysis of St. Paul's


The following sections present the results of the interviews and the statistical analysis of the mini-waste audit, to verify the data collected in the 1992 study.



After speaking with an anonymous source at St. Jerome's, we were able to better understand their composting program. For the interview questions please see Appendix# 1.

How the composting program works:

Problems encountered so far:

In general, the composing system at St. Jerome's is not running effectively. The majority of the organic waste in the bins is rotting and not decomposing because of the issues mentioned above. Also, the composting program is not functioning at full capacity.


In order to try and prevent these issues from occuring at St. Paul's we have determined ways of avoiding these problems:

For other problems associated with composting, please see the trouble shooting chart in Appendix # 3.


After interveiwing Peter Frick, Dean of Residence, Helga Mills, Principal and Ron Turner, Head Chef we had a better understanding of their personal views on implementing a compost program. The following information is based on the interviewers opinions and do not reflect those of Beaver Foods or St. Paul's College. For the interview questions please see Appendix # 2.

All of those interviewed expressed great interest in having a compost system at St. Paul's. It was stated that the compost system would promote three crucial elements in the St. Paul's community:

The challenges that were brought forth were on the maintenance and responsibilities of the staff and residents. The main concerns are:


In order to address these issues we have come up with suggestions to eleviate these concerns. We believe that both the students and the staff should be responsible for composting. Both the staff and students should seperate the compostables from the non-compostables. The students should also be responsible for the maintenace of the composters. This would require Student Council to elect a representative to be responsible for the compost program. That person will co-ordinate volunteers to help turn the compost bins regularily and monitor the composting progress.

The location of the compost bins should be located on the south side of the building to allow for better heating of the compost from the sun. The composters should also be located on soil to allow for the decomposers to enter. The ideal location is near the garbage bins. This will allow for easy access for the student dishwashers to dump both the garbage and the compostables at the end of the dinner shift.

The end result of composting is a dark rich soil. This soil can be used around the college gardens to improve the soil conditions and help the plants to grow. The soil can be taken out of the bins by the groundkeeper and spread around the gardens.

The costs of composting will depend on the number of composters. The Region of Waterloo has composter give away days. This will help reduce the cost of implementation.

Student Council should be responsible for keeping the program running over the years. As well, the kitchen staff should continue to do their part of the composting program.

The organic waste within the the rooms needs to be considered. We feel that this will be a good topic for another ERS 285 project.


Results and Relevance of the Mini-Waste Audit

The goal of the mini-waste audit was to determine if the data obtained in the previous years study was still applicable. We have determined through data analysis that we can use the data from the 1992 study.

The visual inspection showed that the compostable items was very similar to that of the 1992 study. The compost consisted of coffee grids and filters, fruit rinds, tea bags, fruit peelings, vegetables, egg shells and carrot shavings. The 1992 study yielded very similar results because the menu has not changed significantly. With the visual inspection completed the height of waste had the be measured to determine the volume. The calculation of the volume of compost for each day was compared to the 1992 study.

After determining the volume of the compost for each of the days in the mini-waste audit we compared these calculations to the mean amount of organic waste from the previous year. We followed this process:

1) The mean for each of the days in the 1992 study were re-calculated

2) After plotting each of these means, the standard error of the mean, SD/ n(square root), was calculated to yield a maximum and minimum range for which our data was to fall between. This suggested that the past data, and our own data were similar. We have a strong justification for this because each of our measurements fell within the range. The number of degrees of freedom in this question is 2 (n-1, n=3, number of same days used in the study). Using the t-table it was determined that the range would be between +/- 2.484 standard deviations, this can be seen in the graph below.

3) The volume that was obtained for the three days in the was audit were then potted on the graph. (see graph below) Since these values fell within the maximum and minimum range of the previous study, the mini-waste audit data is considered justifiable.

The Volume of Compostables


Since we found that the data collected in previous study was justifiable, we could use their amounts of organic waste to determine the volume of compostables per term. The mean amount of compostable food waste, calculated in 1992, was 0.14 L (+/- 0.06 L) per meal serving. The standard deviation from this mean varies according to the number of weeks in each term.

In order to predict the amount of food waste generated at St.Paul's during the entire year (May 1996 - March 1997), the cafeteria attendance was obtained. Using the number of meals served the estimated volume of food waste was generated for each term (Summer 1996, Fall 1996 and Winter 1997), seen in the charts below. The formulas used were:

The number of meals were given to us with the understanding that we were not to display them on the web. In the winter term we were unable to present a full set of data because it was not available at the time of the table and data tabulation. We chose to display the number of meals in a graph format, to not use the numbers directly.

Total Volumes of Compostables:

The estimated total volume of compost for the three terms was 7,600 L per year. ( This is a sum of the calculated total for each term) The maximum amount of compost is estimated at 8,200 L and the minimum amount of compost is 6,700 L. Based on these totals, we calculated the number of composters that would be needed for the amount of compostables at St Paul's.

Correlation Between Weight and Volume of Compostables:

The data that we have collected concerns both the weight and the volume of compostable food from the St. Paul's kitchen and cafeteria. The volume data has been used for all of the calculations, however we have also calculated the weight for each day as it is useful to compare the weight and volume data. This is done in order to determine if there are similar trends between the data. We have expected that as the weight of compostables increases so will the volume. If there is a strong correlation between the weight and the volume, then it is expected that the density of the compostables will be relatively uniform over time, and therefore, so too will the rate of decomposition and the quality of the compost. However, if there is a weak correlation, then it is expected that varying qualities of compost will be generated.

When such calculations are done the weight and the volume data show somewhat similar trends. A statistical analysis as was done in the previous year's project to determine if the observed similarities in the data are statistically significant. An r value of 0.773 was obtained for St. Paul's showing that there is a moderate-strong, positive correlation. It showed that on some days the weight exceeded the volume, but on other days the opposite occurred. This could be the result of the density of some of the compostable foods compared to others. For example, potatoes have greater density than lettuce leaves.

A moderate-strong, positive correlation between the weight and volume data shows that the data measured in litres can be directly converted in kilograms. This helped us determine the number of composters needed.

Number of Composters Needed:

From all of the information we have obtained we are able to make an estimation of the maximum, minimum and ideal number of composters that would be needed if St. Paul's were to implement a composting program. A single unit backyard composter hold between 150 and 295 kilograms of compost a year. We needed to convert the total, maximum and minimum volumes of the compost during a one year period, from volume in litres to weight in kilograms. This was done using a metric conversion table. Through converting the volumes of compostables into kilograms we get a better picture of approximately how much compost the college produces in one year.

From this we conclude that a minimum of 3, and a mean amount of 6 composters would be needed. The maximum number of composters would be 9, providing for peak periods during the fall and winter terms. Ideally, with the amount of compost that St. Paul's is generating they should purchase 9 single unit backyard composters. This would equal 3 of the 3 unit composters. We think that choosing the maximum number of composters will be the safest choice, if the maximum amount of compostables are to be composted.



The answers to the interviews reflected only the opinions of that one individual person. Therefore, the answers do not reflect a consensus of all those involved in the decision making process. As well, the personal opnions were based on a limited range of knowledge regarding composting.

Waste Audit

There were some errors and limitations in the collection of our data. The first limiation we encountered may have had an effect on the tabulation results. For example, the compost in the buckets were not packed down; therefore, there was room for error in the height measurments. From this limitation a small margin for error could occur. The weigh scale that we used had a 0.01kg accuracy, leaving little room for error.

There are likely to be variations from year to year in the number of students who reside at St.Paul's College, especially during the winter and spring terms. From this we can determine that there will be a slight affect on the amount of compost that the college generates. As the number of students changes there are bound to be changes in the menus/meals served. When the types of meals change so to does the amount of compost that is generated. Thus, it can be expected that there may be variations in the amount of compost due to fluctuations in menus and the number of students.

Composting Program

Finally, the last limitation that we encountered was the rate of decomposition. The rate of decomposition of compostables is dependant upon factors of temperature, and the quality of the compostables. Given that these factors are variable the rate of decomposition will also be variable. Thus, the number of composters required can only be an estimation.


There are several things that can be looked into further with regards to composting at St.Paul's College. If composting is to be implemented at St.Paul's a food and waste flow chart will need to be altered as to indicate that the compostables are not going to the landfill site. There will also need to be a change in the cafeteria floor plan to consider the placement of compost bins, the location of the composters, the various preparation areas in the kitchen and the student flow.

Prior to doing an audit on the amount of compostables produced it is imparitive to educate all those using the compost system. This would include educating the students, the kitchen staff, and the part time dishwashers. This will allow avoid possible errors of what goes into the compost. Also, awarness may increase participation.

A possible project is to determine how students can compost in their rooms. This would mean having composting buckets available in the residents rooms. This would require a ERS 285 group to determine if this is feasible and the methods of accomplishing this.

Through monitoring composting procedures, a study can be done on whether the composting program is working efficently. For example, if there is the right amount of composters, if the compost is being turned regularily and if the right amount of additives are being added. After the compostables have decomposed, an in depth study of the future of the compost would be beneficial. For instance, is there a great need for the product of the compost and if so who uses it; the college, the campus, or outside sources.

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Last updated April 16, 1997.