Karakteristike i obrada otpadne vode koksne industrije

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.Koks je visoko kalorično umjetno gorivo koje se upotrebljava u proizvodnji željeza i čelika, a dobiva se suhom destilacijom ugljena. Proizvodnja koksa zastupljena je širom svijeta, osobito posljednjih godina, kad zbog ekonomskog rasta raste i svjetska potražnja za čelikom, što kao posljedicu ima i povećanu potrebu za koksom. Tijekom proizvodnje koksa nastaju enormne količine toksične otpadne vode izrazito kompleksnog sastava, a prioritetne onečišćujuće tvari koje sadrži su fenoli, cijanidi i tiocijanati. Za uspješno pročišćavanje te vrste otpadne vode i postizanje izlaznih parametara primjena jednog procesa nije dovoljna. Shodno tome, primjenjuje se kombinacija različitih fizikalno-kemijskih i bioloških postupaka obrade, od kojih je biološka obrada najvažnija. U ovom radu dan je literaturni pregled karakteristika otpadne vode koksne industrije i načini njihova pročišćavanja. Osim toga, ovaj pregled osvrće se na složenost i ograničenja povezana s pročišćavanjem koksne otpadne vode, s posebnim naglaskom na metode biološke obrade. Cilj ovog rada je sažeti dosadašnja znanja o otpadnoj vodi koksne industrije, što bi u konačnici pomoglo u optimizaciji postojećih rješenja

Evaluation of Fenton, Photo-Fenton and Fenton-like Processes in Degradation of PE, PP, and PVC Microplastics

The global problem of microplastics in the environment is “inspiring” scientists to find environmentally friendly and economically viable methods to remove these pollutants from the environment. Advanced oxidation processes are among the most promising methods. In this work, the potential of Fenton, photo-Fenton, and Fenton-like processes for the degradation of microplastics from low-density polyethylene (LDPE), polypropylene (PP), and poly(vinyl chloride) (PVC) in water suspensions was investigated. The influence of three parameters on the efficiency of the degradation process was tested: the pH of the medium (3–7), the mass of added iron (10–50 times less than the mass of microplastics), and the mass of added H2O2 (5–25 times more than the mass of added iron). The effectiveness of the treatment was monitored by FTIR-ATR spectroscopy. After 60-min treatments, the PP microparticles were found to be insensitive. In the Fenton treatment of PVC and the photo-Fenton treatment of LDPE and PVC, changes in the FTIR spectra related to the degradation of the microplastics were observed. In these three cases, the treatment parameters were optimized. It was found that a low pH (3) and a high iron mass (optimal values were 1/12 and 1/10 of the mass of the microplastics for LDPE and PVC, respectively) favored all three. The degradation of LDPE by the photo-Fenton treatment was favored by high H2O2 concentrations (25 times higher than the mass of iron), while these concentrations were significantly lower for PVC (11 and 15 times for the Fenton and photo-Fenton treatment, respectively), suggesting that scavenging activity occurs