The aim of the investigation was to determine the impact of the presence of Zn in concentrations of sludges applied in agriculture (exceeding concentrations determined in sludges drained from the treatment plant) 011 the disappearance of PAHs in sewage sludge stored under aerobic conditions. The studies were carried out using dewatered and biochemically stabilized sludges. The changes in the concentration of PAHs were studied in four series: in sludge samples taken after filter press, in sludge with the addition of a standard PAH mixture. in sludge with Zn added, in sludge with the addition of both the standard PAH mixture and Zn. The standard PAH mixture used in the studies contained 16 compounds in benzene - dichloromethane (I: ł) solution with a concentration of 32000 ug/cm' of 16 PAHs. Zn was added to the sludge samples as a solution of chloride zrnc. the final amount was below 2500 mg Zn/kg d.m. (taking into consideration the initial concentrations) The sludge samples were incubated for 90 days at 20°C with limitless access of oxygen. The determination of PAHs in sludge samples was done in duplicates at the beginning of the experiment (the initial concentration) and then six times at I 5-day intervals (after 15. 30. 45. 60. 75 and 90 days). A gas chromatography-mass spectrometry (GC-MS) was used to qualify and quantify the PAHs. I 6 PAI-ls listed by EPA were identified

In the present investigation we have studied the effects of static magnetic field on removal of organic compounds and ammonium nitrogen by high loading activated sludge. The research was carried out on laboratory scale at room temperature. Three or two continuously operating test systems were used in the experiment. In two test systems the return activated sludge was exposed to magnetic field strength of 20 mT or 40 mT. The magnets were attached to a pipe used for activated sludge recirculation. The nitrification rate for test systems when the return activated sludge was exposed to magnetic field was higher than for control system in absence of magnetic field. The best data was observed for test system which was exposed to magnetic field of 40 mT. The nitrification rate was 2 times higher than for control system when the loading of activated sludge was in the range of 0.6 to 0,9 g COD/gMLSS ·d for. The results show that magnetic field improves nitrification of domestic wastewater by high loading activated sludge.

In the present investigation we studied the effects of static magnetic field on transformation of organic compounds and ammonium nitrogen. The research was carried out on laboratory scale at room temperature. Two continuously operating test systems were run in parallel. In one of the systems the raw sewage was exposed to magnetic field strength of 180 mT. The magnets were attached to a pipe used for raw sewage. The second system was used as a control. The research was carried out without activated sludge and with activated sludge. The investigation carried out in an experiment without activated sludge showed that the removal of COD for system with the raw sewage exposed to magnetic field strength of 180 mT was 15% higher then system in absence of magnetic field. During investigation carried out in an experiment with activated sludge it was observed that the removal of COD was similar in both systems. The nitrification rate for system in which raw sewage was exposed to magnetic field was lower than the system in which it was not.

The presented results of research on the effectiveness of enzymatic hydrolysis of lignocellulosic waste, depending on their initial depolymerisation in alkaline medium were considered in the context of the possibility of their further use in the fermentation media focused on the recovery of energy in the form of molecular hydrogen. The aim of this study was to determine the appropriate dose and concentration of a chemical reagent, whose efficiency would be high enough to cause decomposition of the complex, but without an excessive production of by-products which could adversely affect the progress and effectiveness of the enzymatic hydrolysis and fermentation. The effect of treatment on physical-chemical changes of homogenates’ properties such as pH, COD, the concentration of monosaccharide and total sugars and the concentration of total suspended solids and volatile suspended solids was determined. The enzymatic decomposition of lignocellulosic complex was repeatedly more efficient if the sample homogenates were subjected to an initial exposure to NaOH. The degree of conversion of complex sugars into simple sugars during enzymatic hydrolysis of homogenates pre-alkalized to pH 11.5 and 12.0 was 83.3 and 84.2% respectively, which should be sufficient for efficient hydrogen fermentation process.

This paper presents the results of investigation on polycyclic aromatic hydrocarbons (PAHs) concentration in sludge coming from industrial wastewater treatment. The sludge was characterised according to chemical composition and heavy metal contents. Leaching of PAHs from sludge in dynamic conditions was also done with lizymetric columns used to simulate the real conditions during the storage of wastes. The changes or PAHs concentration in sludge stored under various lights conditions were also compared (daylight and darkness). A periodic extraction method with cyclohexane was used to select PAHs from samples. High performance liquid chromatography (HPLC) with fluorescent detector was used to analyse PAHs. Six PAHs listed by WHO were analysed (fluoranthene Fl, benzo(b)fluoranthene BbF, benzo(k)fluoranthene BkF, benzo(a)pyrene BaP, benzo(ghi)perylene BghiP and indeno(l ,2,3-cd)pyrene IP).