Apparently there is so much phosphorus in waste water streams that states are passing laws to exempt water treatment facilities from having to spend billions removing the phosphorus.

I don't get this. I thought that phosphates had been banned in detergents and fertilizer years ago, so where is the phosphorus coming from?


1 Answer 1


Phosphorus & phosphates are a key component of agricultural and garden fertilizers. Most plants need nitrogen (N), phosphorus (P) and potassium (K). They are generally combined into one product called NPK fertilizers.

Nitrogen is needed for leaf growth. Phosphorus is needed for roots, flowers, seeds and fruit and potassium is needed for stem growth and water movement.

The trouble with the use of fertilizers is they get dumped onto plants periodically and the plants cannot use all of the elements in the fertilizer at that time. What isn't absorbed by plants eventually is leached from soil via rain or irrigation water and it ends up in rivers, streams and sometimes lakes.

In Australia, phosphorus can be toxic to some native plants because over millennia Australia's, so called, soil, have been depleted of phosphorus and plants evolved to live with either no or very little phosphorus,

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    $\begingroup$ As I said in my question, I thought phosphates had been banned in industrial fertilizers. $\endgroup$ Commented Jan 24, 2019 at 13:33
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    $\begingroup$ No, phosphorus is a key component of fertilizer as stated above and has not been replaced or banned. Phosphorus is NOT a key component of detergent, from which it has been banned. Phosphorus is also an important component of livestock feed, particularly ruminates. Excess phosphorus is excreted in manure. The focus is on containing farm runoff from either fertilizer or animal waste. I think you're conflating the phosphate ban on detergents and non-essential uses with a ban of all phosphates from all sources. This is all from the US perspective. I have no idea what goes on world-wide. $\endgroup$
    – Tim Nevins
    Commented Jan 24, 2019 at 13:57

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