Filtering Phosphorous

Water conservation is one of the major issues facing the world today, but so is phosphorus depletion. Like oil, phosphorus is a nonrenewable resource. The earth will run out of it someday, and we will lose an absolutely essential fertilizer nutrient for life on our planet.

Phosphorus is mined at only a handful of locations worldwide. As a major component in fertilizer and our food, phosphorus moves from our wastewater systems to our municipal sewage treatment plants. Surprisingly, of the raw sewage entering treatment plants, human urine makes up only 1 percent of the total volume, but it contains 80 percent of all the nutrients.

In Europe, they recognize that every municipal wastewater treatment plant is a potential “phosphorus mine.” If urine were to be processed separately, wastewater plants could be reduced in size, water protection would be improved and the recovered nutrients recycled. In other words, we could keep tons of phosphorous out of our waters!

This would be beneficial in Door County, as phosphorus is the leading nutrient for the cladophora that sullies our shores.

In another approach, Sweden took the lead in harvesting phosphorus at the point of supply…our toilets! They developed the NoMix toilet, which collects urine separately from solid waste. This allows them to collect the urine, store it in tanks for six months, and then use it as fertilizer without being purified. The Swiss are actively studying this system.

Switzerland has also started using some of the NoMix toilets, where a majority interviewed said they had no problem using the new toilets, even men who had to sit rather than stand to use the new units.

With more European countries coming on board with stricter phosphorus restrictions for their wastewater treatment plants, the NoMix toilet may be in all of our futures.

For those intrepid do-it-yourselfers who wish to utilize their own phosphorus resource as a fertilizer for lawns and gardens, we have read of an anonymous blogger who recommends a mixture of one part urine to nine parts water. We do not, however, vouch for the veracity of this source.

Further information is available at

The Door County Environmental Council is an active partner in the Partnership for Phosphate Reduction who contributed information for this article. Information for this article was provided by articles by Paul O’Callaghan, CEO of Clean Tech Development, Canada, and Vincent Landon of