Heavy metal contamination is one of the most important environmental issues. Therefore, appropriate steps need to be taken to reduce heavy metals and metalloids in water to acceptable levels. Several treatment methods have been developed recently to adsorb these pollutants. This paper reviews the ability of residuals generated as a by-product from the water treatment plants to adsorb heavy metals and metalloids from water. Water treatment residuals have great sorption capacities due to their large specific surface area and chemical composition. Sorption capacity is also affected by sorption conditions. A survey of the literature shows that water treatment residuals may be a suitable material for developing an efficient adsorbent for the removal of heavy metals and metalloids from water.

The standard groundwater treatment technology is a simple, non-chemical reagent technology based on aeration and filtration processes. This treatment technology is resulted in the formation of groundwater treatment sludge (GWTS). Because one of the elements of sustainable development is the possibility of their reuse, that water treatment plant operators are looking for new ways of managing these sludges. At present, not all factors determining the adsorptive capacity of water treatment sludge are known. The explanation why the adsorption capacity of sludge with a similar structure and chemical composition may differ significantly will allow for their wider use as adsorbents. The information which must be known to ensure proper sludge management are the quality, chemical composition and texture characteristics of the GWTS. The sludges were characterized by X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy and N₂ adsorption/desorption isotherms. The results showed that the composition and properties of the GWTS depend primarily on the quality parameters of the raw water and the processes and reagents used in its treatment technology. GWTS contains mainly amorphous iron oxides. Sludges are characterized by a large specific surface area (145 m²/g). Due to composition and textural parameters, GWTS demonstrates good adsorption properties toward different compounds such as heavy metals and metalloids. In this article, the authors describe the relationship between properties of resulting sludge and the properties of groundwater, the treatment technology and backwash water treatment from rapid filters.

Groundwater treatment residuals (GWTRs) are safe waste materials generated during drinking water treatment. GWTRs are mainly deposited in landfills, but the preferred solution should be reused or utilized for some components. To ensure proper sludge management, it is important to provide quality, chemical composition, and texture characteristics of GWTRs. Therefore, in this study, we aimed to investigate and compare the features of GWTRs collected from four water treatment plants. GWTRs were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS); Fourier transform infrared spectroscopy (FTIR); thermogravimetric, differential thermogravimetric, and differential thermal analysis (TG, DTG, and DTA, respectively); X-ray fluorescence (XRF); inductively coupled plasma optical emission spectrometry (ICP-OEP); specific surface area (S_BET) measurement; and determination of the isoelectric point (pH_IEP). According to the results, GWTRs are poor crystalline materials that are predominantly composed of ferrihydrite with minor calcite and quartz admixture. They formed heterogeneously mixed particles with irregular shapes. They were mainly composed of iron oxides (32–55%), silica (4–28%), calcium oxide (4–17%), and manganese oxides (0.3–4.0%). They were found to be mesoporous with a large specific surface area. Due to their composition and texture characteristics, GWTRs demonstrate good adsorption properties toward different compounds such as heavy metals and metalloids.

Information concerning the use of non-ionic surfactants (NS) in household products is very scanty. Therefore, a qualitative determination of NS in raw sewage is an alternative source of information concerning the presence and manufacture of NS. The aim of this work was to identify NS in raw sewage (in Poznan and Blonie, both Poland) and treated sewage (in Blonie) and to compare the results with those obtained for river water (Warta in Poznan, Poland). LC-MS/MS was used for this purpose. The presence of 116 ethoxamers, being exclusively polydispersal alcohol ethoxylates (AE) containing alkyl moieties from C₁₀ to C₁₆ and C₁₈, as well as 20 poly(ethylene glycols), was confirmed in the raw sewage, while 68 ethoxamers were found in the treated sewage, including 12 octylphenol ethoxylates. No nonylphenol ethoxylates were identified in the raw or treated sewage.