a b s t r a c tThe decomposition of lignocellulosic raw material included: mechanical grinding of plant biomass, delignification (removal of lignin e this process was conducted in alkaline environment) and detoxification process (removal of alcoholic fermentation inhibitory compounds).The study on producing ethanol from corn straw was based on SSF method which involved conducting simultaneous enzymatic hydrolysis of cellulose and fermentation of obtained saccharides.Based on the study of corn straw alcoholic fermentation it was determined that the way of preparing the raw material in the initial stage of simultaneous saccharification and fermentation, significantly influences the improvement of fermentation yield.In comparison with an attempt in which biomass detoxification process was not implemented, the attempt with detoxification resulted in gaining higher fermentation yield and in lowering the content of aldehydes, methanol and furfural in the produced spirit.Moreover, in the attempts in which detoxification of raw material was used, better actual speed, productivity and the yield of alcoholic fermentation of corn straw was noted. The conducted detoxification in the process of lignocellulosic biomass decomposition improved fermentation yield.

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The objective of this study was to obtain two types of fuels, i.e., bioethanol and biogas, in a sequential combination of biochemical processes from lignocellulosic biomass (corn straw). Waste from the agricultural sector containing lignocellulose structures was used to obtain bioethanol, while the post-fermentation (cellulose stillage) residue obtained from ethanol fermentation was a raw material for the production of high-power biogas in the methane fermentation process. The studies on obtaining ethanol from lignocellulosic substrate were based on the simultaneous saccharification and fermentation (SSF) method, which is a simultaneous hydrolysis of enzymatic cellulose and fermentation of the obtained sugars. Saccharomyces cerevisiae (D-2) in the form of yeast cream was used for bioethanol production. The yeast strain D-2 originated from the collection of the Institute of Agricultural and Food Biotechnology. Volatile compounds identified in the distillates were measured using gas chromatography with flame ionization detector (GC-FID). CH4 and CO2 contained in the biogas were analyzed using a gas chromatograph in isothermal conditions, equipped with thermal conductivity detector (katharometer) with incandescent fiber. Our results show that simultaneous saccharification and fermentation enables production of bioethanol from agricultural residues with management of cellulose stillage in the methane fermentation process.

Abstract:The aim of presented study which was associated with modification of the various work cycle phases duration in the membrane bioreactor, was to reduce the concentration of phosphate phosphorus during the leachate co-treatment with dairy wastewater. The experimental set-up was comprised of the membrane bioreactor equipped with the immersed membrane module installed inside the reactor chamber, and the equalization tank. During the co-treatment experiment performance the excessive activated sludge was constantly removed from the membrane bioreactor in order to keep its concentration at 3.5 g/dm 3 . The load of the sludge with the contaminants was equal to 0.06 g COD/g d.m. d. The concentration of oxygen was equal to 3 mg/dm 3 . The share of the leachates in the co-treated mixture was equal to 10% vol. The membrane bioreactor worked as the sequential biological reactor, in two cycles per day. Duration of each phase was equal as follows: filling -10 min -with concurrent mixing phase lasting for 4 h, aeration phase -1 h, sedimentation -30 min and removal from purified wastewater -30 min. After 4 weeks under these conditions, the modification of the sequential membrane bioreactor's work cycle was made. The duration of particular phases was shortened and two phases of denitrification and nitrification were introduced. Work cycle phases were modified as follows: filling -10 min -with concurrent mixing phase lasting for 3 h, aeration phase -4 h, mixing phase -1 h, aeration phase -3 h, sedimentation -30 min and removal from purified wastewater -30 min. Based on research, it was found that the change in membrane bioreactors' work cycle affects the effectiveness of treated mixture. It was found that the applied modification of phases of the cycle of the MSBR did not affect the concentration of organic compounds and the no significant changes in the concentration of ammonium and nitrate nitrogen in the effluent from the bioreactor were observed, however, the total nitrogen removal efficiency increased by 50%. Alteration of MSBR reactor particular phases duration caused reduction of concentration of P-PO4 3 from 4.7 to 2.9 mg/dm 3 .

A B S T R A C TThe investigations were focused on the determination of the most favorable amount of leachates treated along with a synthetic sewage in a membrane bioreactor. The leachates percentage share was changed over a range of 3-40 vol%. COD and BOD 5 of the leachates varied from 3,000 to 3,500 mg/dm 3 and from 170 to 280 mg/dm 3 respectively. The leachates were characterized by a high concentration of ammonia nitrogen (over 1,000 mg/dm 3 ) and low BOD 5 /COD ratio (0.06 in average), which indicated their negligible susceptibility to biodegradation.The concentration of activated sludge in the membrane bioreactor was maintained within 3.5-4.0 g/dm 3 , the sludge load with contaminants reached the level of 0.1 gCOD/g DM d while the oxygen concentration in the aeration tank was 4.0 mgO 2 /dm 3 . The system operated in a 12-h cycle. The degree of impurities removal was assessed analyzing changes in the following indicators: COD, BOD5, TOC, N-NO À 3 , N-NH þ 4 , P tot . The results revealed that the volume of leachates in the treated mixture of sewage should not exceed 10 vol%. All the tests showed a decrease in COD and BOD 5 of around 90%. The only indicator which exceeded the permissible value was nitrate nitrogen. Thus, the leachates purified by activated sludge were additionally treated by reverse osmosis.