The observed increase in the diversity and level of pollutant content in the water environment forces the development of more effective technologies for their removal. Using nanomaterials in water and wastewater treatment offers numerous opportunities to remove organic and inorganic contaminants that are hardly removable in conventional processes. In this group, carbon-based nanomaterials, mainly carbon nanotubes (CNTs), graphene (Gr), and graphene oxide (GO), are very popular. This review aims to present the directions and diversity of applications of carbon-based nanomaterials (CNMs) in water and wastewater technology, as well as the challenges and environmental dangers that new solutions entail. Authors also present the results of the research on the changes in properties of GO produced in the laboratory as water suspension and a freeze-dried product over time. The results confirm the significant influence of the form of graphene oxide and its storage time on the structural properties, hydrophilicity, and stability of GO. Therefore, they should be considered when selecting an adsorbent or reaction catalyst in environmental applications for developing new greener and sustainable methods of treatment and purification, which use fewer reagents and release safer products.

The paper reviews the patent descriptions of methods for obtaining humic substances and the procedures used in their industrial production. Selected humus substances, obtained using three different methods, were also examined. In the first one, humic substances were obtained due to the hydrolytic-oxidative decomposition of lignosulfonate. The second one consists of alkaline extraction from brown coal. According to the third, humus substances were extracted from digested sewage sludge. In the obtained humus substances, molecular composition, inorganic impurities, IR spectrum, gravimetric analysis, and the % shares of fulvic and humic acids were determined. The physico-chemical properties of the tested substances were also assessed. Based on the study’s results, the advantages and disadvantages of the obtained humus substances were determined, and methods for their modification to improve utility values were provided. Research on humic substances is a very important issue, especially concerning improving soil management and developing sustainable agricultural practices. They are key in improving soil structure and increasing its capacity to retain water and essential nutrients such as N, P, K, S, Ca, and Mg. In addition, humic substances are an important store of carbon in soils, which is important in the context of climate change.

The purpose of this paper is to present the IZO application that calculates and visualizes coefficients of adsorption isotherms according to Freundlich, Langmuir, and BET in a classic and linear system, in a simple communicative way. The application also calculates the working time of the adsorption bed based on the transformation of the mass balance equation, and according to the Zuchowicki, Zabieziński, Tichonow, and the Bohart-Adams equations. The laboratory tests of the adsorption process of leachate from a municipal landfill on selected active coals ORGANOSORB 10, DESOTEK, and BA-10, were conducted to check the program for accuracy. Results of tests confirm that the linearization method of the calculation of adsorption isotherms coefficients, used in the IZO application, gives sufficient accuracy and may be used as an alternative of, e.g., the nonlinear estimation method.

The article presents research on using the adsorption process of aldrin (a chloro-organic pesticide that most often occurs in the environment near expired pesticide burials). The research used three sorbents: two activated carbons and compost from sewage sludge as a low-cost sorbent. Obtained adsorption isotherms belong to the L group according to the Giles classification. The test results and their analysis confirm that the IZO application facilitates the analysis of the adsorption process. The study results also confirm that compost can be a cost-effective alternative to commercial activated carbons to build barriers protecting the environment against existing leaking expired pesticide burials.

Due to its nitrogen, phosphorus, and magnesium content, sewage sludge is used, among other things, to grow plants for energy purposes or to intensify biogas production. These processes are always accompanied by odor emissions, which are treated as pollution according to European legislation and are subject to legal regulations in many countries. Therefore, this publication presents the results of a study on the removal of odor from sewage sludge by adsorption on biochars produced from selected biowaste. Beekeeping waste (grain) and coffee brewing residues (spent coffee grounds) were selected for the study. Both materials were pyrolyzed to produce biochar which was applied for adsorption of odors from sewage sludge. Commercial Organosorb 200-1 Wi activated carbon was used as a comparison material. The odors were taken from dried sewage sludge from a municipal wastewater treatment plant. The obtained biochars are suitable for odor adsorption and can be an alternative to commercial adsorbents. The biochar from beekeeping waste showed the highest efficiency, allowing 100% odor removal. Slightly worse results were obtained for biochar from spent coffee grounds.