At the Four Seasons, Philadelphia, green is always in seasonWhen Philadelphia's mayor announced a plan last year to make the city the greenest in the country by 2015, the Four Seasons Hotel there was already moving toward sustainability. Since 2005, the hotel has reduced its water pressure,  implemented a colder wash cycle for laundry  and replaced hundreds of incandescent light bulbs.
I spoke with Marvin Dixon, the hotel's director of engineering, about some of the big steps toward sustainability taken there recently. Among them are a composting program, which in one year reduced the waste the hotel sent to a landfill by about 120 tons, a rooftop garden and microturbines -- a first for a Philadelphia business.	
	      
		

How long does the material for the compost actually stay in the hotel? Is there a compost pile somewhere inside the Four Seasons?
It gets removed about every  two to three  days. It sits at our dock. We have a refrigerated room out there and whenever we get a load --  which is about a ton --  we'll pick it up and we take it to a compost farm out in Montgomery County. They'll mix that in with  horse manure, old hay, wood chips.
Do you bring the compost back once it's ready to use  in the roof garden? Talk about starting the roof garden. 
We bagged up finished compost. We made all of our beds out of native white oak. We filled it with compost and then planted a couple dozen different varieties of herbs, fall vegetables. We had lettuces and radishes, peppers, snow peas.
We're not trying to grow all of our own herbs. We just think it's a very cool and neat thing to do. For special events that we sponsor, lunches or dinners, we'll incorporate some of the stuff from our garden in the meal. It's not that we really get a lot out of the garden, but it represents what can be done. Our employees take better ownership in our composting program because they know what it's doing.
How do the microturbines work and what do they do?
We take a turbine engine and we run a generator and we make our own electricity. Today, I'm producing 25 percent of the hotel's electrical needs 20 percent cheaper than  I can buy it. Then, I get all this rejected heat from those engines.  That's enough heat to heat all the hot water that  I need for the kitchen, for the laundry and for all the guest rooms. And I still have enough heat from those engines to do 10 to 15 percent of the building's heat. That makes it an extremely efficient operation.
What else do you have in the works?
When we put the microturbines in we converted our heating loop in the building. We're constantly circulating this water throughout the  building. Now that we got that in place, we have a means of capturing heat in other areas and putting it in that loop. For instance, on the cook line we have about  eight or nine  pieces of equipment that use  gas. As we burn the gas and cook the food, we have this huge fan on top of the building that sucks it out. What we want to do is put a heat recovery system on that exhaust hood, so before we dump all that heat into the atmosphere, we'll grab the heat we can out of it and put it in that loop and use it to heat the hot water or heat the building or heat the pool or wash the laundry. Now, we have a way to recapture the heat or energy that we purchased, store it and use it when we need it.
Photo: Four Seasons Hotel Philadelphia