Sonification
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- 2. CONTENTS: INTRODUCTION CHEMICAL TREATMENT BIOLOGICAL PRE TRATMENT ULTRASOUND DEVICE ULTRA SONIC MECHANISM CONCLUSION REFENCES 2
- 3. • Sonication : Is the act of applying sound energy to agitate particles in a sample, for various purposes. • Sonication can be used to remove dissolved gases from liquids by sonicating the liquid. 3
- 4. • The domestic waste water is mostly treated by biological process such as activated sludge process, aerobic pond, and anaerobic treatment. • The anaerobic stabilization is a slow process. Therefore, long residence times in the digester and large digester volumes are required. 4
- 5. Why sonication??? • This sludge disintegration is performed by using the sonication • It is one of the disintegration methodology. 5
- 6. CHEMICAL TREATMENT: • The pH of the sludge is increased up to 12 • Maintained over a period of 24 hours • This process may be used to hydrolysis and decompose lipids, hydrocarbons and proteins into smaller soluble substances such as aliphatic acids, polysaccharides and amino acids 6
- 7. POSITIVES AND NEGATIVES OF ALKALINE HYDROLYSIS • Low energetic requirements. • Very good dewater ability of the final sludge. • Modification of the sludge composition. • Possible damage to the bacteria responsible for the Microbiologic activities. • Bad odor generation. • Corrosion and fouling of the equipment. • Higher COD in the final effluent due to the presence of non-biodegradable substances. 7
- 8. Biological pre-treatments: • The biochemical sludge disintegration is based on enzyme activity that are either produced within the system or externally. • The enzymatic lyses crack the compounds of the cell wallaby an enzyme catalysed reaction. • This process is of interest in combination with mechanical disintegration as well, because enzymes are also located in the intracellular liquid Positive and negative 8
- 9. POSITIVES AND NEGATIVES • Low energy consumption. • No stress on the equipment. • High cost. • The usage of enzymes to better the sludge stability is not clear. • High generation of odors. 9
- 10. Ultrasound Device: • The WAS samples was sonicated using Sonics ultrasound unit,. • Ultra Sonic uses piezoelectric ceramics to generate ultrasound. ULTRA SOUND DEVICE 10
- 11. • The repetition of the increase respective decrease of the ceramics dimension is created by the electrical fields changing polarity. • The changes in the ceramics dimensions create ultrasound of a specific frequency. Three major components of an ultrasound system are 1. converter (transducer) 2. booster and 3. horn (sonotrode) 11
- 12. ULTRASONIC MECHANISM: The impact of ultrasound waves on a liquid causes the periodical compression (Positive pressures) and rarefaction (negative pressures)of the medium. This phenomenon is termed cavitation. Micro bubbles occur in rarefaction due to the negative pressure. These micro bubbles also known as cavitation bubbles, essentially containing vaporized liquid and gas that was previously dissolved in the liquid. 12
- 13. As the wave fronts propagate, micro bubbles oscillate under the influence of positive pressure. Cavitation bubbles first grow in size until reach resonant bubble size within a few microseconds and then violently collapse when they reach its critical size 13
- 14. USES: It is very innovative in the field of waste activated sludge treatment obtained from domestic waste water plant . It reduces the retention time by 25% with comparison to without ultra sonication process . It reduces, amount of sludge produced by 30% in comparison to conventional anaerobic digestion. 14
- 15. There is appreciable increase in methane production from ultrasonic treated waste with respect to different ultra sonication time and power inputs . It also destruct volatile and non volatile impurities present in water by mechanism of cavitation. It reduces the digester volume . 15
- 16. CONCLUSION: Apart from this it controls the foaming of sludge by killing filamentous bacteria and other pathogens. Due to these reasons this method of sludge treatment can become crucial way of waste sludge treatment. 16
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Editor's Notes
- #5: Waste activated sludge process is more efficient technology to meet stringent standard. It results in the generation of a considerable amount of activated sludge that has to be wasted . The expense for excess sludge treatment has been estimated to be up to 60% of the total operating cost of a wastewater treatment plant Moreover the conventional disposal method of land filling causes secondary pollution problems. Therefore, an interest in methods to reduce the volume and mass of excess sludge has been growing rapidly. . For the purpose of reducing the volume of sludge, anaerobic digestion has been widely used.
- #6: The aim of such pre treatment is to rupture the cell wall and membrane to the release the intra and extracellular matter into the aqueous phase for subsequent degradation, and this process is called sludge disintegration.
- #11: The ultrasound unit has a maximum power output of 200W and operates at a Constant frequency of 20 kHz. The power input can be set independently from40 - 200 W. .
- #12: A converter basically converts electrical energy into ultrasound energy (vibration). The booster is a mechanical amplifier that helps to increase the amplitude generated by the converter. The horn is a specially designed tool that delivers the ultrasonic energy to the sludge. Figure 3.2 shows the Arrangement of converter, booster and horn in a typical ultrasound system. The booster is designed and tuned to operate at a desired frequency.
- #13: Ultrasonic disintegration is a well-known method for the break-up of microbial cells to extract intracellular material During the low-pressure cycle, the ultrasonic waves create small vacuum bubbles in the liquid that collapse violently during a high-pressure cycle.