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Thursday, Nov. 6, 2003
OLD NIC'S NOTEBOOK
Where there's muck -- there's crystals of money
A fertile mind at the cutting edge of sewage
By C.W. NICOL
I just got back from Vancouver, Canada, where I was staying with my dear old friend Fred Koch and his wife Akiko. I first met Fred back in the early 1970s when I worked for the Environmental Protection Service in Canada, and when Fred, then a keen young engineer, was hired by EPS to do some contract work. In 1983 Fred began doing research on the biological treatment of sewage, at a pilot plant set up in trailers right next to the woods in the grounds of the University of British Columbia. Fred himself always called his place of work "The Poo Plant."
His research involved the use of bacteria which raised the temperature of sewage sludge enough to pasteurize it; the study of bacteria that internally store phosphate; and the use of membranes in a new process to separate solids and liquids, instead of the usual treatment of letting solids settle out in lagoons or tanks.
These remarkable membranes, which look like transparent spaghetti, can even filter out viruses from water. This technology, which was originally developed by Kazuo Yamamoto of Tokyo University, using Mitsubishi Rayon membrane filters, is now being further enhanced by a Canadian environmental-services company, Zenen Environmental.
In Fred's poo plant I saw how air was pulsed through tanks of the murky mixture to keep the outer surfaces of the membranes from clogging up. I saw, too, the clear water that came out of the system (but declined to taste it). This submerged membrane technology is proving to be an excellent tool to biologically remove phosphorous from municipal and industrial waste waters.
Forgive me if I take a little space to remind you that phosphorous is a non-metallic element. White or yellow phosphorous glows in the dark and is highly flammable and poisonous. Red phosphorous doesn't glow, is less flammable and not so toxic. Phosphorous, which does not occur alone in nature, was discovered in 1669 by a German called Brandt, who used heat to extract it from urine -- a very smelly process no doubt.
Phosphate is a salt or ester of phosphoric acid. Many of these compounds are essential to life. For example, our body fluids and soft tissues contain mostly sodium and potassium phosphates. Calcium phosphate comprises more than half the weight of bones; tooth enamel is composed 80-90 percent of the same substance. Brains and nerve tissues contain large amounts of phosphates.
Fred, patiently trying to explain his work to this old thick head, while I sat on a battered couch in his office, scribbling notes, told me that after the microbes had digested the sludge, what was left was rich in minerals. The phosphate in the sludge is bio-available and easily released. One removal process involves adding what he called "short-chain volatile acids." When I looked dumb he said, "volatile fatty acids." When that didn't work either, he said, "For example, acetic acid." I knew that one -- like in vinegar, right? Anyway, phosphate, ammonium and small amounts of magnesium are taken out and concentrated, in crystals of magnesium ammonium phosphate -- commonly known as MAP -- a substance whose mineral name is struvite.
Fred then took me to a tall and transparent reactor to see the final process in which the white crystals were performing a marvelous dance, roiling around in liquid, binding up like rolling snowballs to make small white pellets. Once removed and dried, these pellets make a wonderful slow-release fertilizer.
In nature, the roots of many plants release citric acid into the soil around them, helping them to dissolve and take up phosphates. The trouble with a lot of conventional phosphate fertilizers is that they are quickly dissolved and go right into the ground water. Too much of this can cause water pollution. These pellets release phosphate at the rates that plant roots demand. Fred calls it "intelligent fertilizer."
When people talk about the phosphate used in fertilizers, detergents and so on, they usually refer to calcium phosphate that is mined from deposits in various parts of the world. This phosphate rock is naturally insoluble and must be treated with sulfuric acid. These reserves are now severely depleted but are in increasing global demand. A serious problem is that these phosphates, depending on where they are mined, can often contain heavy-metal contaminants such as cadmium, uranium, nickel, chromium, copper, zinc and mercury. It is a costly process to remove these when regulations demand it. So far, world regulations, varying from nation to nation, have been lax about this when it comes to commercial fertilizers. This, however, is changing.
In Canada, Fred's work is being applied at pilot plants in Penticton, on Lulu Island (Vancouver) and in the city of Saskatoon, Saskatchewan. A new plant has been designed for Calgary, Alberta, and Fred is hoping a full-scale system will be running there by next year.
Fred and fellow researchers also hope to go on to the recovery and recycling of carbon from sewage and animal wastes, to make such things as biodegradable plastics.
We talked of a future when each community could recycle sewage and farm waste to produce pure phosphates, plastic and other valuable products, while at the same time making waste water pure -- even potable enough to put back into nature's cycles without harm.
Another example Fred talked about was dead fish from fish farms. Salmon farms in particular are sometimes decimated by viruses. This rotten fish is all too often buried on land. Bio-treatment could produce heat to kill all viruses, and then the nutrients in the fish could be recovered and sensibly reused.
Fred compared his work with sewage to the customs of the old city of Edo, where all "night soil" was returned to the land. "But ours doesn't have that whiffy reek, and no parasites or germs," he said.
Here in Nagano, I live in a small community that is gearing up to spend billions of yen for a sewage system that won't do any of this recycling. The dairy farmers must now stop piling cow manure in small mountains on their land. This is going to cost a lot of money. I have talked about making methane for heating energy, and about other ways of recycling, but out here in never-never land such talk almost always falls on deaf ears. I know that research in Japan is paralleling Fred's work, and that a lot of intelligent folk can see that this is the way for Japan to be less polluted and less reliant on imports.
Eventually, I hope we'll get our, er . . . "stuff" together. As my old grandad used to say: "Where there's muck there's money." Fred's little white pellets will surely become very valuable indeed -- and they aren't even smelly.