{"id":116557,"date":"2023-03-04T18:15:50","date_gmt":"2023-03-04T23:15:50","guid":{"rendered":"https:\/\/savethewater.org\/?p=116557"},"modified":"2023-03-04T18:15:50","modified_gmt":"2023-03-04T23:15:50","slug":"thermal-hydrolysis-of-sewage-sludge-an-upgrade-in-wastewater-management-technology","status":"publish","type":"post","link":"https:\/\/savethewater.org\/thermal-hydrolysis-of-sewage-sludge-an-upgrade-in-wastewater-management-technology\/","title":{"rendered":"Thermal Hydrolysis of Sewage Sludge: An Upgrade in Wastewater Management Technology"},"content":{"rendered":"
By Sakshi Kabra Malpani, <\/span>Publishing Associate: Researcher and Writer <\/span>at Save the Water\u2122 | March 04, 2023<\/span><\/p>\n Pure and clean drinking water is our basic right. Poor and outdated wastewater management technologies are one of the big hurdles on this road. <\/span>Thermal hydrolysis of sewage sludge is an upgraded technology to treat wastewater<\/span><\/a>. <\/span>Upmanu Lall, director of the Columbia Water Center<\/span><\/a> has also stated that it\u2019s high time <\/span>to improve wastewater treatment technologies<\/span><\/a> to secure safer drinking water for coming generations.<\/span><\/p>\n Thermal hydrolysis uses steam to <\/span>treat sewage sludge<\/span><\/a> or wet organic wastes present in wastewater. It\u2019s used prior to <\/span>anaerobic digestion<\/span><\/a> in wastewater treatment plants. This process requires high temperatures\u00a0 of around 140 to 170 \u00b0C and pressure of about six to nine bars.<\/span><\/p>\n During this process, steam releases energy at a high pressure. This increases the reactivity of water and destroys the chemical bonds of the sewage sludge. Post wastewater treatment, people use sewage sludge as bio-compost to enrich soil nutrients. Thus, it\u2019s very important to treat sewage sludge appropriately.<\/span><\/p>\n Wastewater treatment plants treat wastewater from sewage systems, and solid wastes are separated from liquid wastes. <\/span>These solid wastes form sewage sludge, which can then be further treated or processed by thermal hydrolysis.<\/span><\/a> Sewage sludge has two types: <\/span>primary sludge and secondary\u2013or waste-activated\u2013sludge<\/span><\/a>. Primary sludge has higher fibrous and lipid content, but less phosphorus and protein content. In contrast, secondary sludge contains more organic matter such as carbohydrates, proteins, microbial cells, etc.<\/span><\/p>\n After thermal hydrolysis, anaerobic digestion of the sewage sludge takes place, where bacteria breaks it down. Sewage sludge may contain dangerous chemicals and metals leached from industrial, household, municipal, and medical wastes. It also contains non-biodegradable organic matter.<\/span><\/p>\n Thermal hydrolysis is carried out in a batch process. The apparatus consists of <\/span>a pulper, reactor, and flash tank<\/span><\/a>. The process follows three steps:<\/span><\/p>\n The treated warm sewage sludge is then cooled to room temperature using heat exchangers. Lastly, it\u2019s fed to digesters for the next process of anaerobic digestion.<\/span><\/p>\n Thermal hydrolysis has multiple benefits:<\/span><\/p>\n Thermal hydrolysis consumes a lot of energy. It takes place in the absence of oxygen gas and other oxidants. Therefore, after treatment, the color of the sludge darkens. This dark-colored sludge can reduce the efficiency of later steps of wastewater treatment. For example, it can hinder the <\/span>Ultraviolet<\/span><\/a> disinfection process. To overcome these challenges, thermal hydrolysis can be replaced with an <\/span>advanced thermal hydrolysis process<\/span><\/a>. This process involves the use of oxidants.<\/span><\/p>\nThermal Hydrolysis<\/span><\/h2>\n
Sewage Sludge<\/span><\/h2>\n
Steps of Thermal Hydrolysis<\/span><\/h2>\n
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Advantages of Thermal Hydrolysis<\/span><\/h2>\n
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Drawbacks of Thermal Hydrolysis<\/span><\/h2>\n
What Can You Do?<\/span><\/h2>\n