Humic acid (HA) impairs water quality due to its reactivity with many substances present in water. During the drinking-water treatment process and water distribution via water supply system, HA present in water may react with chlorine and other disinfects <br /> producing harmful disinfection by-products (DBPs), which are categorized by the International Agency for Research on Cancer (IARC) in groups 2A (probably carcinogenic to humans) or 2B (possibly carcinogenic to humans). Several studies have investigated and reported increased HA removal by iron-coated sorbents. Therefore, the aim of this study was to examine the removal of HA from water by two commercially available bituminous coal-based activated carbons (ACs), Cullar D (Cm) and Hydraffin 30N (Hm). Prior to testing the chosen adsorbents were chemically modified according to two protocols: (1) oxidation by acid mixture (m1), and (2) oxidation with acid mixture followed by iron-ions impregnation (m2). The batch adsorption tests were used to test their efficiency in HA removal under various values of process parameters (initial HA concentration, pH, contact time, adsorbent mass, and temperature). The results showed that up to 96 % of HA removal can be obtained by Cullar D modification Cm1, while maximum uptake of HA by Hydraffin 30N modification was achieved with Hm1 (62.1 %). After surface saturation with Fe3+ –ions (m2), both activated carbons showed similar and lower performances in HA removal (Cm2 up to 66.5 %, and Hm2 up to 50.3 %). FTIR analysis confirmed differences in modified AC structures, as well as favorable structure of Cm1 for HA adsorption.

Coke is a high-calorie carbon mass obtained by dry distillation of coal, and used in various processes, the most significant of which is production of iron and steel. Coke production is present worldwide, especially in recent years when due to economic growth the global demand for steel is growing, which consequently increases demand for coke. During coke production, enormous amounts of toxic wastewater of extremely complex composition are generated. Priority pollutants that coking wastewater contains are phenols, cyanides, and thiocyanates. For successful treatment of such wastewater and achieving safety discharge standards, the application of a single process is insufficient. Accordingly, a combination of different physicochemical and biological treatment procedures, of which biological treatment is the most important, should be applied. In this article, a literature review of coking wastewater characteristics and treatment technologies is presented. In addition, this review addresses the complexity and limitations associated with coking wastewater treatment, with special emphasis on biological treatment methods. The aim of this review was to summarise the current knowledge on coking wastewater treatment technologies, which could eventually help optimisation of existing solutions.