The objective of this study was to determine the effect of advanced oxidation process with the use of Fenton’s reaction on the effectiveness of anaerobic treatment of wastewaters originating from the wood industry that were characterized by a high concentration of formaldehyde. Experiments were established to analyze changes in COD content and in the concentration of formaldehyde in treated wastewaters, additional analyses were carried out to assay quantitative and qualitative changes in the biogas produced. The first stage of the experiment involved analyses of the effectiveness of the tested wastewaters treatment only in the process of methane fermentation. At the second stage of the experiment, the biological process was preceded by chemical pre-treatment of wastewaters with Fenton’s reagent. The conducted study proved that the investigated variants of chemical pre-treatment of wastewaters had a significant effect on increasing the total biogas production. In contrast, no significant effect of the applied technology was demonstrated on changes in the concentration of the analyzed contaminants in the treated wastewaters.

An HPLC-DAD method was developed for the determination of formaldehyde in animal feed and silage. The method is based on the determination of the product of chemical reaction between formaldehyde and 2,4-dinitrophenylhydrazine. A 3 g of feed or silage were extracted with Milli-Q water with phosphoric acid and next formaldehyde was derivative with the use 2,4-dinitrophenyl- hydrazine in acetronitrile solution. The extract was purified with 0.45 µm syringe filters and separeted on Zorbax Eclipse XDB C18 column and detection was carried out at 360 nm. Formal- dehyde was eluted with a mobile phase consisting of acetonitrile/water in isocratic elution. This method provided average recoveries of 90.6% to 102.2%, with CVs of 2.6% to 6.4% for feed and from 91.3% to 108.7% with CVs of 1.1% to 4.1% for silage in the ranged of 50 to 1000 mg/kg feeds and silage. The LOD and LOQ for formaldehyde in feed and silage ranged from 1.6 to 2.6 and 2.7 to 5.7 mg/kg, respectively. The methodology was applied for the analysis of feed and silage samples collected from poultry, pigs and cows farms.

Chemical bonded resin sand mould system has high dimensional accuracy, surface finish and sand mould properties compared to green

sand mould system. The mould cavity prepared under chemical bonded sand mould system must produce sufficient permeability and

hardness to withstand sand drop while pouring molten metal through ladle. The demand for improved values of permeability and mould

hardness depends on systematic study and analysis of influencing variables namely grain fineness number, setting time, percent of resin

and hardener. Try-error experiment methods and analysis were considered impractical in actual foundry practice due to the associated cost.

Experimental matrices of central composite design allow conducting minimum experiments that provide complete insight of the process.

Statistical significance of influencing variables and their interaction were determined to control the process. Analysis of variance

(ANOVA) test was conducted to validate the model statistically. Mathematical equation was derived separately for mould hardness and

permeability, which are expressed as a non-linear function of input variables based on the collected experimental input-output data. The

developed model prediction accuracy for practical usefulness was tested with 10 random experimental conditions. The decision variables

for higher mould hardness and permeability were determined using desirability function approach. The prediction results were found to be

consistent with experimental values.