P-Recovery on the Move
INSTEAD OF REMOVING PHOSPHATES FROM WASTE STREAMS, TECHNOLOGY IS NOW EMERGING TO RECOVER THIS VITAL RESOURCE.
Unlike fossil fuels or precious metals, phosphorus has no alternatives — we (and all other life forms on the planet) need phosphorus; it’s in our DNA, our bones and our energy-producing chemicals (ATP). We get it from our food — meat, grains and vegetables — so it’s not surprising that phosphorus is a key ingredient in fertilizer, as well as a component of sewage, manure and slaughterhouse waste (bone meal).
Sewage, for example, contains about 1–2% phosphorus. Although some of this phosphorus can be “recycled” by land application of sewage sludge on farmland, plant uptake is limited because the phosphorus is bound as compounds that can’t be metabolized. As a result, the unused phosphates find their way into waterways (runoff), causing eutrophication of rivers and lakes.
In addition, the practice of spreading manure and sewage sludge is coming under scrutiny for health and safety reasons due to the presence of other pollutants, such as organic compounds and heavy metals. In Germany, for example, about half of the sewage sludge generated is still used for land application, but the practice is now forbidden in two states (Bavaria and Baden-Württemberg); and environmental legislation tends to be one directional — more stringent, never less.
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