A case study problem is an example situation. Case studies can be relatively simple or detailed, depending on your objectives and the amount of time you have. Case studies are open-ended, allowing participants to synthesize solutions to a problem. There usually are many correct answers. Case studies allow participants to learn from each other. Case studies also provide trainers with an assessment of how well the participants have mastered the information presented.
The case study is prepared using either fictional or actual data, or some combination of the fictional plus actual data. For example, for a biosolids application case study you could use a real site (so people can find it in on a map) together with fictional information about biosolids quality. A good approach for case studies is to use actual information whenever possible, but always change the name of the source (e.g., use real biosolids quality data with an imaginary city name). Using fictional names also allows people to have fun with people and place names that are rarely found in real life.
We most often use case studies for group problem solving, but this approach also could be used for testing or individual study.
The case study presentation method suggested here is one way of using a case study with a group. There are many other options. Be creative!
For a case study involving participant groups, you first must explain the situation (provide data). Usually a written explanation is used, but you also could provide data in the form of slides, videotape, or other media. After providing the case study data, assign participants to smaller groups to analyze and propose solutions for the case. After groups have formulated a solution, ask the smaller groups give a presentation on their findings to the larger group. After the small group reports are complete, the facilitator summarizes the findings of the small groups and provides additional observations. It is important for the facilitator to recognize innovative solutions to the case study problem, even if radically different from what he had in mind.
The case study presented here was used at the end of an extended training session on biosolids quality and land application management. Our objective was to get participants to apply their accumulated knowledge.
Participants were given data on a city's effort to comply with EPA Part 503 regulations (see below). They are asked to evaluate the city's compliance in small groups of five to eight people. After 20 to 30 minutes to prepare an assessment, each small group presented its findings to the larger group. At the conclusion, the facilitator discussed several items that the small groups failed to consider.
The current date is 1998. You are employed by the City of Ecotopia wastewater treatment facility. You recently were appointed biosolids coordinator. It is your job to assure that the city meets all monitoring and record-keeping requirements connected with biosolids quality. You also are to supervise the city's contractors and land application sites. The facility has a design capacity of 2 MGD with dry weather flow of 0.4 MGD.
Raw solids from wastewater treatment are discharged to a lagoon. Every 6 years, the city contracts with a custom dredge operator to remove accumulated solids from the bottom of the lagoon. Sam's Udredge It, a dredging contractor, has a contract to dredge the lagoon in the coming year. The contract specifies liquid biosolids with 2 to 6 percent total solids.
The city received wastewater from one large industrial facility, Copper-Zinc Alloys Inc., from 1981 to 1996. The lagoon was last dredged in 1992. Copper-Zinc Alloys Inc. no longer discharges to the wastewater facility.
Rancher Bob, who raises beef cattle on the Singing River Ranch, has received biosolids ("sewage sludge" before 1993) from your treatment facility since the 1970s. He has 2,000 acres, which include critical riparian habitat for the endangered yellow-nosed suckerfish. In the past, the City hauled liquid sludge to Bob's on-farm storage (a large concrete tank). Bob's employees then mixed the biosolids with additional water and irrigated it on pastures with a pressurized, big gun applicator. Mr. Black, the previous biosolids manager, entered into a 20-year contract to deliver all of the City's biosolids to Rancher Bob on the City's behalf. The contract expires in 2008.
Your new mayor, who directly oversees the treatment facility, recently was elected as a candidate for the We Love the Earth party. She is concerned that the solids in the lagoon are contaminated and will have to be sent to a hazardous waste landfill.
The previous biosolids coordinator, Mr. Black, left you the following biosolids analyses from the last two times the lagoon was dredged:
Element 1992 Concentration
mg/kg1986 Concentration
mg/kgCadmium 10
12
Copper 4,000
5,000
Lead 200
250
Nickel 50
70
Zinc 8,000
10,000
You have called a meeting of other personnel from your wastewater treatment facility. Your mission, together with the other members of your team, is to revamp the City's biosolids program to meet EPA requirements. Specifically, the mayor wants the answer to these questions: