Lidia Wolny

Enhancing Anaerobic Fermentation of Sewage Sludge for Increasing Biogas Generation

Abstract The article presents results of biogas generation from sewage sludge after applying two pretreatment methods: sonification and thermal hydrolysis. Original results and literature data of the ultrasonic field influence on biogas generation were compared with literature data concerning effectiveness of the thermal hydrolysis. Sludge pretreatment by the ultrasonic field intensified the biogas production as the amounts of biogas was of ca. 20–24% higher, as compared to the nontreated sludge. The highest generation of biogas was observed after a shorter time. The degree of organic matter reduction was of 45–47%. The content of volatile fatty acids dropped down to 139 mg CH3COOH dm−3 during 20 days. During the thermal pretreatment of sludge the amounts of generated biogas were ca. 25% higher, as compared to nontreated sludge. The maximum biogas production of 0.92 dm3 was observed in the day 9 of fermentation. To-date results indicate that efficiency of ultrasonic disintegration depends on sonification time, type of heads, as well as power and frequency transmitted to heads.

Ultrasonic aiding of selected pharmaceuticals removal from wastewater

AbstractIn the paper, the problem of water pollution risks with pharmaceuticals was discussed. The results of the investigation from different countries are shown. Polish results are presented as well. Particular emphasis was put on water pollution with non-steroidal anti-inflammatory and psychoactive drugs. The need for additional disinfection of drinking water has been highlighted. The aim of this study was to evaluate the ultrasonic (US) process on the degradation of pharmaceuticals. For testing non-steroidal anti-inflammatory and analgesic drugs were selected. The tests were performed using Malvern Mastersizer 2000 particle size analyzer with a sonotrode. The samples were exposed to an ultrasonic field with parameters 250 W and 20 kHz. During the experiment, sonication time was altered and it was equalled to 30, 60, 120, and 240 s. Based on the results, the relationship between the ultrasonic field, length of its duration, and particles’ diameters was determined. Particle sizes were strongly correlate...

Evaluation of dewatered sludge properties from a selected municipal sewage treatment plant

AbstractAn incorrectly maintained sludge management in wastewater treatment plants, may cause a major threat to the natural environment. Sewage sludge and supernatant, as by-products of the sewage treatment process, generate various chemical substances, including toxins. The aim of the study was to determine the physicochemical characteristics of sludge, sampled from a selected municipal wastewater treatment plant of a throughput of 9000 m3/d. The supernatant and water extract of tested sludge were also determined. The tests were carried out in compliance with the accredited methods for municipal sewage sludge. The heavy metal content of tested sludge does not exceed the amounts specified for their use in agriculture and for land reclamation. Taking into consideration the use of polyelectrolytes in the sludge conditioning process, some examinations were performed using a gas chromatography electron-capture detector to determine the polyacryloamide content. Thus the concentration of this compound in the wa...

Ecotoxicity Assessment of Stabilized Sewage Sludge from Municipal Sewage Treatment Plant

Abstract Aim of this study was to evaluate the ecotoxicity of municipal sewage sludge conditioned with polyelectrolytes, taken from selected sewage treatment plant. Using the bioindication analysis overall toxicity was assessed, which allows to know the total toxicity of all the harmful substances contained in sewage sludge, in many cases acting synergistically. To prepare a sample of sludge for the basic test, all analyses were performed with a ratio of liquid to solid of 10:1 (water extract). Daphnia pulex biological screening test was used. A dilution series of an water extract of sludge were prepared to include within its scope the lowest concentration that causes 100% effect and the highest producing less than 10% of the effect within a specified range of the assay. The results of the test were read after 24 and 48 hours. Based on the research and analysis of test results it proved that the sewage sludge conditioned with polyelectrolytes exhibit the characteristics of eco-toxic.