Risk Analysis of Heavy Metals Migration from Sewage Sludge of Wastewater Treatment Plants

Abstract

More and more attention in sewage sludge management is being devoted to its environmental utilization. This approach is justified both from economic and environmental points of view. However, as with any method, there are certain possibilities and limitations. The goal of the natural utilization of sewage sludge is to recover the valuable agronomic properties and fertilizing potential of the sludge. The main aspect limiting the possibility of using sludge as a fertilizer is the heavy metal content. In this paper, an analysis of the risk of environmental contamination in the case of application of sewage sludge with different forms of sludge treatment was carried out. Risk indices such as Igeo and PERI, based on the comparison of total metal content in sludge and soil, as well as RAC and ERD indices, which take into account the mobility of metals in soil, were calculated. It was shown that high levels of potential risk and geoaccumulation indicators do not necessarily disqualify the use of sewage sludge, the key aspect is the form of mobility in which the heavy metals are found in the sludge, and this should be the only aspect taken into account for the possibility of their environmental use.

Ecological and human health risk assessment of heavy metals in sewage sludge produced in Silesian Voivodeship, Poland: a case study

“…Similar results were presented by Sundha et al ( 2022 ), who showed that sludge samples were high to extremely contaminated with cadmium ( I geo = 4.1 to 4.12) and moderately to highly and highly to extremely polluted with zinc ( I geo = 2.4 to 4.7). In contrary to our research, Kowalik et al ( 2022 ) indicated that SS from four WWTPs in Poland (Świętokrzyskie Voivodeship) were heavily to extremely and extremely contaminated with Zn, and heavily to heavily to extremely with Cd.…”