Case studies   Thorpe Wood Conference Center   This Conference center is located in the Catoctin Mountains of Western Maryland where the sewage disposal is at a premium. Many homes and business need to have large septic fields or tanks to handle there waste, the need to construct a system, which can handle the needs of the center, is very important.   This center is completely self-contained with the reuse of water, including greywater and blackwater. No water is needed for the toilets since they have used composting toilets. The air flowing system, which they used for Clivus fixtures, keeps them oder-free and highly sanitized compared to conventional sewage toilets. Another benefit of these toilets is they cannot clog nor overflow, unless the holding tanks are not emptied.     With the center only being a few years old it will be almost 5 years before the composting toilets will need to be emptied. The compost that will be removed will then be used on site for the flowerbeds around the complex. The composted urine is also turned into liquid fertilizer, which can also be used on the American Chestnuts seedlings, which surround the site. Both of these receptacles are located in the utility room which is located behind the main lecture hall for easy access to the by products. The liquid fertilizer is stored in a 600-gallon storage tank, which needs to be emptied about twice a year into a mobile tank.   The greywater system recycles all of the water, which is used in the dishwashers, and sinks of the center. The tanks, which receive the dirty water, are located throughout the grounds and place in locations for irrigation of the landscape. There are return pipes from the tanks back to a larger storage tank to supply the center with water for no drinking uses and if there is an excess of water it can then be returned as clean ground water.