 All of the following is 'recycled' to create extra 'food' EXCEPT for:
Food, on the other hand, is a challenge shipmen face three times a day, so central to their thoughts that a history of sea-faring can be read from a commissary list. Should any groundsman dispute the importance of belly-furniture in history—whether it be exterminating whales, or introducing syphilis to the Fiji Islanders, or settling the Australian littoral with cross-coves from Middlesex and Hampshire—he is referred to the hundred-and-first chapter of Moby Dick , a book spooled in the amusement tanks of all but the smallest spacers. Nimitz's men won their war on canned pork and beans. The Triton made her underwater periplus of Earth with a galley stocked with frozen pizza and concentrated apple-juice. The earliest men into the vacuum swallowed protein squeezings from aluminum tubes, and were glad enough to drop back to the groundsman's diet of steak and fried potatoes. Long before I was a boy in Med School, itching to look at black sky through a view-port, galley science had fulfilled the disgusting exordium of Isaiah 36:12, to feed the Slimeheads for breakfast today what was day-before-yesterday's table-scraps and jakes-water. The Ship's Cook, the man who accomplishes the daily miracle of turning offal into eatables, is in many ways the most vital man aboard a spacer. Cooking aboard a spacer is a job combining the more frustrating tensions of biochemistry, applied mycology, high-speed farming, dietetics and sewage engineering. It's the Cook's responsibility to see that each man aboard gets each day no less than five pounds of water, two pounds of oxygen, and one-and-a-half pounds of dry food. Twelve tons of water, oxygen, and food would have filled the cargo compartments to bursting, and left a small ship like the C. P. Sale no reason to reach for Mars. By allowing a colony of Chlorella algae to work over our used air, water and other effluvia, though, three tons of metabolites would see us through from Brady Station to Piano West and back. The molecule of carbohydrate, fat, protein or mineral that didn't feed the crew fed the algae. All waste was used to fertilize our liquid fields. The algae—dried by the Cook, bleached with methyl alcohol to kill the smell and make the residue more digestible, disguised and seasoned in a hundred ways—served as a sort of meat-and-potatoes that never quite wore out.
 bones
 urine  hair  algae  bones