Environmental regulations in Europe are often forerunners of US regulations, after some lag time and adjustment to US conditions. So, it may be of some use to take a quick look at what is happening in Germany in regard to the phosphorus occurring in municipal wastewater sludges.
Germany differs from the US in that it has no phosphorus reserves within its borders. Much of the world’s phosphorus is found in Morocco, which has just under 79% of the total reserves. By contrast, the US has 2.2% and China has 5.8% of global phosphorus reserves. Consequently, phosphorus is a “strategic resource” in Germany, that must be managed carefully. New regulations have been adopted that require high levels of phosphorus recovery from sewage sludge, and prohibit the use of sludge for agricultural use. These regulations will be phased in over the next 12 to15 years, depending on the size of the plant.
The new regulations do not specify any specific technology for recovery, but the options could be broken down into removal directly from dried sludge, or removal from the ash from incineration. Recovery from the ash is more complex, but the recovery rates are very high when compared to direct precipitation of the phosphorus from wet sludge. The choice of technology will probably depend on the specific circumstances at each plant. Recovery from ash will have a built in bias at plants with existing incinerators, but it is probable that these new regulations will help drive the installation of some new ones in the future.