Smol et al. discussed the potential for the use of sewage sludge ash (SSA) in Poland as a source of phosphorus for agriculture. Other sources for phosphorus in Poland are noted to be limited and to be currently uneconomic to harvest. Roughly 20,000 metric tons (MT) of SSA were generated in Poland in 2014, and both EU and Polish laws encourage the use of SSA instead of its disposal. The largest current sources of SSA are in or near large cities, requiring transport of SSA to agricultural areas; however, economies of scale are most favorable near the larger sources of sewage sludge. Most of potential SSA capacity is in villages, near fields where it could be used as a phosphorus source, but incinerators are required to convert the bulk sewage sludge to SSA. A second problem is the level of contaminants in SSA. Previous evaluations of SSA indicate that it may be too high in cadmium and lead to be used on agricultural fields under the relevant EU regulations, with measurements of Cd and Pb levels of 3-25 ppm and 20-750 ppm, respectively, though the levels in SSA may differ from previous evaluations. It is also possible that the levels of heavy metals and other contaminants in SSA may be lower than those in more urban or industrial areas (because their levels in the water being treated should be lower), making their use in local agricultural fields more attractive. For smaller sources of SSA, mobile facilities may be useful or necessary for further use. If the levels of contaminants are consistent with those measured previously, SSA in Poland (or the sludge from which it is generated) may require further treatment, increasing the costs for its use.