Xities or the Cities of the Future in Space

Philadelphia October 2, 2005 Peter Kokh writes in last month’s Moon Miner Manifesto, see www.asi.org, about Xities, the cities of the future in space. Mr. Kokh envisions these Xities as self sufficient in producing their own breathable atmosphere, food, and clean water. Mr. Kokh distinguishes all the cities of the Earth even in the future from the modern Xities which he believes will reside only outside of the Earth’s atmosphere. I’m not sure I even like Mr. Kokh’s concept of Xities. They remind me most of medieval walled cities which allowed none of the peasants or slaves to enter or leave, or even change occupations, which were mostly performed for no pay, in bad conditions, and for bad food. Medieval cities were designed to be self-sufficient for water and stored food only in times of war when the cities were besieged. Earth cities, evolved as sites of business both trade and manufacture. The health both physically and economically of Earth cities and most likely the Xities will depend on the health of the surrounding countryside and vice versa. Early cities never lacked fresh air, or did they? Medieval cities all depended on burning wood, peat, dung or coal for heat. As late as the 1900’s London, a city which predates medieval times, was noted for foul smelling, sulfurous, choking fogs resulting from thousands of coal and wood fireplaces in the city. Carbon monoxide poisoning and skin and lung cancers from smoky fumes from ones own and one’s neighbors smoking fireplaces were common as were often lethal fires. There was no water treatment in medieval cities. In Venice, also another city which predates medieval times, still has most toilets flush directly into the lagoon which forms most of the streets in Venice. Many tourists still avoid eating seafood in Venice due to fear of cholera, and the hepatitises which used to be very common there, but probably less common than in the neighboring cities as the Venetian water supply came from rain water which is free of cholera if the water delivery system remains free of waste water. Unfortunately, Mr. Kokh doesn’t understand modern water recycling terms which grade water as white, gray, and black. White water is generally considered to be pure and uncontaminated with any chemicals. Rain water running directly into a gutter or storm drain without picking up any silt or soil run off would be white water. Gray water would be any water that might contain light contamination with chemicals such as dishwashing detergent, car washing detergent, or light contamination with harmless and biodegradable agricultural or industrial chemicals but contains no human or animal wastes. Gray water is water you could put directly on your garden without fear it would harm the plants, soil, or contaminate with disease organisms any plants grown there. Black water would be toilet, shower, or hand washing, or clothes washing water which might be contaminated with human or plant pathogens. Black water would also be considered as any which might contain animal wastes or chemical contamination with harmful or persistent chemicals. Until late in the 19th century, water recycling was at best haphazard. Yes, there were sewer systems back 2500 years ago in the Indus valley, now Pakistan. But the concept of diseases acquired from bad water was probably still lacking back then, even there. The sewer systems probably resulted from the desire of the nobles to be able to get out of their carriages without sinking into mud in the city streets, which resulted from the city residents tossing contents of their chamber pots and kitchen wastes into the city streets. The streams the sewers emptied into were probably still fished and drunk from. In this country, the common water borne diseases of cholera and typhoid were not recognized as related to contaminated drinking water until well into the 20th century. Many physicians remained unconvinced of the germ theory of disease into the 1910's. The Romans some 2000 years ago had some continuously flushing toilets. Fresh, continuously flowing water was channeled through communal toilets in the local baths. But the Romans still enjoyed eating the oysters from London’s river Thames, which was then the sewer system of London. However, as back then, the water was never chlorinated, the sewer systems’ and streams’ microbes were able to release the nitrogen from the wastes faster than in most modern treatment systems. Although modern water treatment plants use black water recycling microbes quite resistant to common chlorine contents of water, some may still be very susceptible to being destroyed by modern agricultural chemical contaminants and difficult to maintain in some water treatment systems. Although the microbes may remove the nitrogen very effectively and cheaply, they do not necessarily remove all the pathogens, or many other chemical contaminants besides the nitrogen, so do not constitute a complete recycling system by themselves. Let me point out, the Wolverton system, see http://www.wolvertonenvironmental.com does not convert toilet wastes into anything drinkable or even ready to be let out of a sewer system or used directly on the garden. Nor, judging from the data, does the Wolverton system remove all the nitrogenous waste from the effluent. Unfortunately, most of the details of the system are lacking from the site, which sells Dr. Wolverton’s book. Dr. Wolverton worked for NASA who looked into water recycling systems starting in the 1970’s. Dr. Wolverton’s site also has some data on common indoor air pollutants, and references to some of the free NASA maintained sites for information on biological reduction of air and water pollutants. The web pages of Mr. Wolverton and the NASA sites are informative but neither the free NASA sites nor Mr. Wolverton’s book can be considered current state of the art. Atmosphere recycling these days is probably not quite as advanced as water recycling systems were in the late 19th century. Everybody who studies these problems know Biosphere I and Biosphere II that attempted to recycle atmosphere in closed systems using only biological methods were total failures. They were designed to recycle the atmosphere, water and nutrients for a few human residents and some animals. The walls of Biosphere II which were unfinished concrete absorbed oxygen. Plants died. Oxygen became so scarce the residents took to surreptitiously opening the dome to get an influx of oxygen. Although the plants in the Biospheres may well have been capable of recycling enough oxygen to keep the people alive, if all the plants had lived, the amount of oxygen consumed by decomposing wastes and the farm animals may not have been totally provided for even if all the plants had lived. But there was a lot learned from these failures. NASA has done some experiments with biological atmosphere recycling systems for use on the International Space Station and when we go back to the Moon. It is now known that one cubic meter of growing wheat supplies enough oxygen to support one adult man. Likewise one aspen tree in full leaf produces enough oxygen to support one adult man. But those are just two species of plants out of millions. NASA has made commitments to using renewable atmosphere recycling systems starting in 2008 for the International Space Station, but what they are going to be has not yet been published on the free areas of the NASA site. Most people who raise plants in their apartments or houses are not raising them for oxygen production or carbon dioxide and carbon monoxide and other pollutant cleaning they provide. After all how many philodendron leaves does it take to supply the oxygen for one person? Or cactus pads? Or gallons of plankton? Or quarts of fresh water algae? And in what lighting conditions? With what fertilizers or lack thereof? Who knows? I personally am convinced most of the available oxygen in center city Philadelphia was produced by the algae on the walls of the buildings and subways. Unfortunately, they washed the subway walls once back in 1976 for the bicentennial with something that actually killed off most of the algae growing there. Since then, the oxygen supply in the subways probably dropped by half and the carbon monoxide levels doubled. If NASA has done the research on how many philodendron leaves or square feet of algae coated walls it takes to produce the oxygen for one person, they haven’t published that data, at least not on the information available to the general public on their free web pages. And now when I want to grow freshwater algae to feed to my fish, I have to send away mail order to another state for freshwater algae cultures to get any microalgae to produce oxygen and food for my fish. I used to just go down into the subways and take a swab off the subway walls to get my algae growing in a new tank. Instead of fresh smelling, oxygen producing algae, they now have just some foul smelling, mildew growing on the walls of the subways. Although like most Philadelphians, I spend no small amount of time bad mouthing this city in particular and most cities in general, Philadelphia has the biggest park system within the city borders of any American city complete with a wild deer herd also usually mostly found within city limits. Being wild, the deer herd roams at will in and out of the city. There also is an operating agricultural school and working farm within city limits. But in addition to the traditional agriculture within the city, there are a number of businesses that produce food commercially using hydroponics within the city limits. Philadelphia is far from being self sufficient in food or water recycling, but the local farms provide much of the food sold in the city. In addition there are numerous city gardens in public spaces organized and assisted by the Pennsylvania horticultural society. But one thing is known, however, no matter where we go in space, to what strange planets and in what massive space ships there will be plants going with us. On the International Space Station, that has all its air recycled by mechanical recyclers, the astronauts kept and maintained an onion plant, that sprouted spontaneously from the fresh food shipped up on one of their regular resupply shipments, just to have something green and living sharing their living space. Somehow, I never pictured the International Space Station as a possible home for anyone until I heard they had a plant. Once they had a plant, kept not for some experiment, but just because it was alive and green, the International Space Station was no longer just an outpost. It was a home. By Janice Guidotti, M.D., PASA member(Philadelphia Area Space Alliance)