Distribution of Oxyphinic Elements in Sewage Sludge Fractions Based on Manganese and Nickel

Abstract

Owing to the chemical composition of sewage sludge (SS), it may be used as an alternative to fertilizers; however, before land application, it must be assessed in terms of its contents of heavy metals considering their potential mobility in the soil. The aim of this study was focused on evaluating the potential mobility of oxyphinic elements -Mn and Ni in SS. The samples were collected from 4 different wastewaters treatment plants located in the Wielkopolska province at the same time points in 3 consecutive years. The levels of Mn and Ni were assessed using the BCR sequential method. The risk assessment code, and individual contamination factor were additionally calculated. The sewage sludge from small WWTPs was characterised by significantly lower amounts of metals in comparison to those originating from the large ones. It was found that both metals were dominant in loosely and relatively loosely bound fractions of all analyzed SS. It was confirmed by high values of risk assessment codes and individual contamination factor. Mn and Ni belonging to the group of oxyphinic elements showed significant similarities in the distribution of SS fractions. Large and rapidly activated pool of Mn and Ni may be a beneficial and valuable source of nutrients for plants, but certain dangers related to the possible accumulation of these elements in soils could be also considered.

Human and ecotoxicological risk assessment of heavy metals in polymer post treatment sludge from Barekese Drinking Water Treatment Plant, Kumasi

“…This study revealed a mean concentration of 7.82 ± 2.43 mg/kg for manganese, with concentrations ranging from 5.02 to 9.39 mg/kg. It is worth noting that there seems to be no maximum amount of Mn in biosolids because it represents a valuable micronutrient for plants, birds, and animals, and poses a low hazard to the environment [26] , [41] . Our findings indicated a lower mean concentration of Mn, compared to sewage sludge in Poland which documented concentrations between 65.43 and 224.19 mg/kg [26] .…”

“…It is worth noting that there seems to be no maximum amount of Mn in biosolids because it represents a valuable micronutrient for plants, birds, and animals, and poses a low hazard to the environment [26] , [41] . Our findings indicated a lower mean concentration of Mn, compared to sewage sludge in Poland which documented concentrations between 65.43 and 224.19 mg/kg [26] . Concentrations of Mn in PTS at Barekese WTP may be attributed to the utilization of brown calcitic lime in drinking water treatment, which contains higher amounts of Mn than white lime owing to its low manganese content [42] .…”

“…Risk assessment is frequently used to estimate potential health or ecological threats as well as the likelihood of detrimental impacts on the environment [26] . The use of polymer post-treatment sludge for land application or as feedstock for fish organisms can pose an environmental risk that can be evaluated using a variety of risk assessment models, including Nemerow's synthetic pollution index, cancer and non-cancer risk, the geo-accumulation index (Igeo), the contamination factor (CF), the potential ecological risk index (PERI), the pollution load index (PLI), the metal pollution index (MPI), the polymetallic contaminant index (PmCI), the ecological risk index (ERI), the risk assessment code (RAC) [21] , [22] , [27] .…”

“…Ecotoxicity tests are an excellent method of determining the environmental impact of biosolids put into the soil or near aquatic habitats and examining their potential impacts on organisms. Because it is not always possible to anticipate toxicity directly from chemical data, the outcome of ecotoxicity tests on a variety of organisms can be informative for the general public [26] , [28] .…”

Quantitative Distribution and Contamination Risk Assessment of Cu and Zn in Municipal Sewage Sludge

“…Of course, this is essential information, and the total contents of heavy metals in SS can provide important but general knowledge. However, toxicity, mobility, bioavailability, and geochemical processes of metals in the environment depend strongly on their geochemical fraction [11,[21][22][23]. Generally, metals can be found in various forms: water-soluble, exchangeable, carbonate-bound, bound to Mn, Fe oxides and hydroxides, bound to organic matter, or they appear in the residual fraction.…”