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Sewage Sludge Disintegration Using Ozone-a Method of Enhancing the Anaerobic Stabilization of Sewage Sludge
| Content Provider | Semantic Scholar |
|---|---|
| Author | Vranitzky, Robert |
| Copyright Year | 2003 |
| Abstract | The anaerobic digestion process is a proven technique for effective sewage sludge treatment. However, during anaerobic treatment, as a rule only about 50% of the organic matter in sludge is readily susceptible to biodegradation into biogas, the other half of the organic material being more recalcitrant and degrading very slowly. The combination of anaerobic sludge digestion with disintegration using ozone is seen as one promising technical and economic method of enhancing the stabilization process. Through the implementation of sludge ozonization, refractory organic structures are oxidized and converted into biodegradable low-molecular compounds. Hence, a substantially increased degree of sludge stabilization can be achieved. Basically, the disintegration process is accomplished by the application of ozone to break down cell walls. Thus, cell walls are fragmented and intracellular compounds are released. The product can be utilized as a substrate in the anaerobic biological process. The following paper focuses on the investigation of (a) the overall disintegration efficiency of ozonization at different ozone doses; (b) the achievable degree of stabilization for disintegrated sludge as compared to partly digested sludge and raw sludge; and (c) process performance in continuous operation and the resulting reload to wastewater treatment derived from sludgewater recycling. Additionally, a cost calculation for a model wastewater treatment plant of 20,000 m3/d capacity was carried out to prove the economic feasibility of the process. Initial ozonization experiments showed that only 0.06 g O3 / g DS was necessary to destroy the biological activity of treated biomass. In order to investigate the achievable degree of stabilization, both specific digestion batch tests and continuous experiments were conducted. The basic experimental set-up for the continuous experiment consisted of: (a) a wastewater treatment unit; (b) a sludge treatment unit; and (c) an ozonization unit. The tests conducted provide evidence of an increase in the average degradation rate of organic matter to 65%, as compared to 45% in the conventional system. At the same time, an increase of 30-40% in biogas production (70% methane and 30% carbon dioxide) was observed due to disintegrated addition dosage, thus proving that no inhibitory by-products are generated during ozonization. The wastewater treatment efficiency was monitored and special attention was paid to the effects of sludgewater recharge to the wastewater treatment unit. Thus, the achieved removal rate of carbon and nutrients was slightly decreased, but remained in line with the legal requirements. Hence, it can be assumed that the sludgewater recharge had no significant impact on nitrogen removal. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.docum-enter.com/get/f-5KEhiXXlIJnHsLH6I1xQ1TUuiK1vk_88oAop-mOfM,/SEWAGE-SLUDGE-DISINTEGRATION-USING-OZONE.pdf |
| Alternate Webpage(s) | http://www.wabag.com/wp-content/uploads/2012/04/Sewage-sludge.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
