| Abstract [eng] |
Biogas is a clean and renewable form of energy can replace conventional energy sources, the use of which causes ecological problems. Biogas can be produced from municipal and industrial wastewater treatment plant sludge. The sludge resulting from wastewater treatment facilities is a big problem. Its management can be spent up to 50% of operating expenditure. Sludge utilization of anaerobic digestion is widely prevalent in the stabilization process in which the sludge is converted into a stable from, which do not have unpleasant odors and less polluting products, as well as energy recovery - biogas (Caporgno et al., 2015). Biogas production, solid, water content, the removal of pathogens and the kinetics of the process can be modified using different treatment techniques (Yeneneh et al., 2015). Treatment collapsible structure of complex organic compounds into simple molecules, which are more sensitive for biodegradable (Santoh et al., 2004; Yeneneh et al., 2015). Treatment also helps to speed up the hydrolysis (first step of methane production), which is the limiting factor in the process, if the substrate is not readily biodegradable (Braguglia et al., 2015). The aim of this experiment is to evaluate the sewage sludge treatment with ultrasound and electric hydraulic discharge (EI) influence readily biodegradable and biogas production. Before anaerobic digestion sludge was treated with ultrasound (20 min., the amount of energy - 0.24 kJ/l) and electric hydraulic discharge (30 min., 78 kJ/l). During the experiment conducted sewage sludge digestion mesophilic conditions (35 °C). Sewage sludge treatment pH had little effect on the optimal and remained within the limits required for anaerobic digestion (6,8 − 7,2). Ultrasonic treatment resulted in the highest dry matter content decreases after the anaerobic digestion (29%), EI treatment - 28% and untreated sewage sludge - 23%. The largest decrease in the COD received untreated sludge after anaerobic digestion - 32.4%, followed by EI - 28.7% and 25.12% after treatment with ultrasound. From untreated sludge after anaerobic digestion biogas extracted 1170 ml, treated with ultrasound for 19% higher amount (1400 ml) and then treated EI 2% more biogas (1200 ml). Further study, it is recommended to apply substrate mixing Total of anaerobic digestion, because it accelerated the process itself, as well as to ensure a uniform temperature throughout the bioreactor. Requires the implementation of a continuous pH and ORP measurement of total anaerobic digestion time, it would help to have more control the process. Because after ultrasonic treatment of sewage sludge COD, dry matter content decreased more and releasing biogas increased more, compared to the EI processing, further research should be applied to different duration and intensity of ultrasonic treatment. |
