Iwona Zawieja

Effect of Ultrasound Field on Dewatering of Sewage Sludge

Effect of Ultrasound Field on Dewatering of Sewage Sludge The paper presents the investigations aimed at the determination of the effect of time and wavelength of ultrasound field on the value of capillary suction time (CST), sludge thickening and dry matter of the excess sludge subjected to the process of stabilization. The investigations were carried out on the excess sludge which comes from communal waste treatment plant. The sludge was exposed to ultrasound field, using ultrasound generator with power of 1500 W, frequency of 20 kHz and amplitude 39.42 μm (which corresponded to the amplitude of 100%). Sonication of the sludge was carried out for different amplitudes and sonication times. The non-conditioned sludge and the sludge initially conditioned with ultrasound field were subjected to the process of stabilization in laboratory flasks (V = 0.5 dm3) for the period of 10 days. On each day, sludge thickening and dewatering capacities were determined. The sludge subjected to the effect of ultrasound field exhibited elevated levels of CST. However, the sonication time had positive effect on the increase in the degree of thickening for each of the amplitudes studied. Also, the process of stabilization positively affected final thickening and dewatering of the sludge. Wpływ Pola Ultradźwiękowego na Odwadnianie Osadów Ściekowych W artykule przedstawiono badania mające na celu określenie wpływu czasu i długości fali pola ultradźwiękowego na wartości czasu ssania kapilarnego (CSK), zagęszczania oraz suchej masy osadów nadmiernych poddanych procesowi stabilizacji. Do badań wykorzystano osady nadmierne pochodzące z komunalnej oczyszczalni ścieków. Osady poddano działaniu ekspozycji pola UD, wykorzystując procesor ultradźwiękowy o mocy 1500 W, częstotliwości 20 kHz i długości fali 39,42 μm (co odpowiadało amplitudzie równej 100%). Nadźwiękawianie osadów prowadzono przy różnych długościach fal i czasach sonifikacji. Osady niekondycjonowane oraz wstępnie kondycjonowane polem UD poddano procesowi stabilizacji w kolbach laboratoryjnych (V = 0,5 dm3) przez okres 10 dni. W każdym dniu prowadzenia procesu oznaczano zdolność osadów do ich zagęszczania i odwadniania. Osady poddane działaniu pola UD posiadały wyższe wartości CSK. Czas nadźwiękawiania miał jednak pozytywny wpływ na zwiększenie stopnia zagęszczania dla każdej z badanych amplitud. Również proces stabilizacji wpłynął pozytywnie na końcowe zagęszczanie i odwadnianie badanych osadów.

Hybrid conditioning before anaerobic digestion for the improvement of sewage sludge dewatering

AbstractSo far, the most common method of conditioning to increase the efficiency of sludge dewatering is by adding chemicals (polyelectrolytes). This method effectively increases dewatering, thus causing the possibility of getting into the environment of hazardous chemicals. The use of physical conditioning methods (thermal, ultrasonic field) or a combination one (so-called hybrid conditioning) is an alternative to chemical methods for sludge preparing. A preliminary modification of excess sludge before the fermentation process affects the stabilization process, thereby changing the parameters characterizing the efficiency of sewage sludge dewatering. The article presents a study determining the impact of pre-conditioning of excess sludge before anaerobic stabilization on the final efficiency of their dewatering. Sludge conditioning methods of thermal and ultrasonic pre-treatment and combination of these two methods (hybrid conditioning) were used. The ability of sludge dewatering was determined on the b...

Impact of the excess sludge modification with selected chemical reagents on the increase of dissolved organic substances concentration compounds transformations in activated sludge

ABSTRACT Submission of excess sludge initial disintegration process significantly affects the efficiency of anaerobic stabilization process. Expression of increasing the concentration of organic matter in dissolved form is to increase sludge disintegration. As a result of chemical modification is an increase of the chemical oxygen demand and the concentration of volatile fatty acids. The aim of this study was to determine the impact of the disintegration process with selected chemical reagents to increase the concentration of organic substances in dissolved form. The process of chemical disintegration of excess sludge was treated using the following reagents: Mg(OH)2, Ca(OH)2, HCl, H2SO4, H2O2. The modification was carried out at ambient temperature for 2, 6 and 24 h. During sludge disintegration it was noticed the growth of indicators values that confirmed the susceptibility of prepared sludge to biodegradation. HighlightsSludge disintegration method.The increase of disintegration degree.The increase of COD and VFAs.

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...

Effect of peracetic acid disintegration on the acceleration of hydrolysis process

AbstractExcess sludge is difficult to be processed and it is hydrolytically degraded under both anaerobic and aerobic conditions, since a high proportion of the sludge comprise living micro-organisms. The key phenomenon that occurs during the process of disintegration of sewage sludge is destruction of cell walls in micro-organisms caused by physical, chemical or biological factors. Consequently, sludge is fragmented and some intracellular components are released into the surrounding liquid. In order to determine the best parameters of acid disintegration of excess sludge, the study examined the effectiveness of oxidizing treatment with peracetic acid. STERIDIAL W 15 solution, which is a mixture of PAA (15%), hydrogen peroxide (10%), acetic acid (36%) and water (39%) was used in the study. Pre-treatment in the ambient temperature prior to the period of 1 and 24 h was conducted. The doses of peracetic acid of 0.1–5 mL of STERIDIAL/L of excess sludge were used (as for the organic dry matter content correspo...