1. ENVIRONMENTAL DISASTERS
Section 6.4 & 6.5

2. Section 6.4- Solutions to Thermal Pollution
Once Through Cooling Method – (most common) uses water from a river or lake and returns it after it absorbs heat from a condenser; can be a problem in aquatic ecosystems
Cooling Towers – prevents thermal pollution, but can be expensive to build
Cooling Ponds – a nice alternative that can be used to house fish that like warm water, but land must be available

3. Waste-Heat Greenhouses
Crop producers can utilize waste heat from a power plant to help reduce energy costs in growing their vegetables
Warm water normally sent to a cooling tower is sent through pipes to heat-exchange systems in the greenhouses
A back-up system must be used for additional heat and for when the power plant is shut down
Energy costs are reduced by about 80%

4. Aquaculture with Wastewater
Brunner Island, Penn. – Power Plant produces electricity and catfish with an experimental fish farm – aquaculture
A coal-fired power plant discharges its heated wastewater to heat a greenhouse producing hydroponic grown vegetables August through March
The wastewater is also used to heat incubators for hatching catfish eggs; once hatched they are transferred to long concrete pools
Warm wastewater also helps keep the pools around 80oF (the optimum temperature for catfish is 84oF)
It takes 36 weeks for the catfish to become the size they would in about two to three years in a natural environment

5. Section 6.5- Three Mile Island
March 28, 1979 along Susquehanna River in Pennsylvania, the Three Mile Island Nuclear power plant
A pressure relief valve opened and remained open allowing coolant water to escape, causing the temperature of the core of the reactor to exceed 5,000 oF
The reactor’s containment vessel was designed to prevent the release of radioactive materials, and it did function properly
Only low levels of radioactive gases were released
Five years after the accident the state conducted a study to compare new cancer cases to those that would have normally been expected, called an observed vs. expected survey

6. Total cancer cases, breast cancer in females, respiratory, digestive system and skin cancers were compared
The study showed no pattern in cancer incidence in relation to the distance from the Three Mile Island power plant
There was also no “rising trend” in leukemia found
Numerous studies have occurred as a result of the accident; however, not all findings are in agreement
Some point to increased cancers as a result of the accident and others do not
Regardless of the real effects of the accident, it is one that we can learn from