Shokoohi Reza, Rahmani Alireza, Asgari Ghorban, Dargahi Abdollah, Vaziri Yaser, Abbasi Mohammad Attar
Department of Environmental Health Engineering, Faculty of Health, Hamadan University of Medical Science, Hamadan, Iran.
Pak J Biol Sci. 2017;20(5):260-266. doi: 10.3923/pjbs.2017.260.266.
Sludge stabilization process in terms of operational, environmental and economic indexes is the most important stage of treatment and its disposal. This study was aimed to determine the performance of Autothermal Thermophilic Aerobic Digestion (ATAD) system as one of the low-cost and biocompatible methods of sludge treatment.
This study has been done using a laboratory scale Autothermal Thermophilic Aerobic Digestion (ATAD). The reactor was consisted of two polyethylene tanks with a final capacity of 100 L for each tank. Both tanks with all fittings were installed on a metal frame. The variables of study were temperature, dissolved oxygen, pH, volatile organic compounds, total solids, COD and the number of Ascaris eggs and fecal coliforms per gram of dry matter of the sludge. The temperature was measured hourly and the pH and dissolved oxygen were measured and controlled twice per day. One-way ANNOVA was applied to analyze reasults.
According to the results, the temperature of sludge increased from 11.7-61.2°C by biological reactions. Pathogen organisms were reduced from 80×106 to 503 in number during 72 h. After 6 days pathogen organisms and Ascaris eggs were removed completely. Volatile organic compounds and COD were reduced 42 and 38.3% respectively during the 6 days.
It is concluded that the performance of ATAD in removing organic compounds from wastewater sludge were desirable. Resulted sludge from stabilization process were appropriate for use in agriculture as a soil supplement and met the indexes of class A sludge according to EPA's standards (CFR 40 Part 503).
从运行、环境和经济指标来看，污泥稳定化过程是处理及其处置的最重要阶段。本研究旨在确定自热嗜热需氧消化（ATAD）系统作为一种低成本且生物相容性好的污泥处理方法的性能。
本研究使用实验室规模的自热嗜热需氧消化（ATAD）进行。反应器由两个聚乙烯罐组成，每个罐的最终容量为100升。两个带所有配件的罐都安装在金属框架上。研究变量包括温度、溶解氧、pH值、挥发性有机化合物、总固体、化学需氧量以及每克污泥干物质中的蛔虫卵数量和粪大肠菌群数量。每小时测量一次温度，每天测量并控制两次pH值和溶解氧。采用单因素方差分析来分析结果。
根据结果，通过生物反应，污泥温度从11.7°C升高到61.2°C。在72小时内，致病生物体数量从80×10⁶减少到503。6天后，致病生物体和蛔虫卵被完全去除。在这6天内，挥发性有机化合物和化学需氧量分别降低了42%和38.3%。
得出结论，ATAD在去除废水污泥中的有机化合物方面性能良好。稳定化过程产生的污泥适合作为土壤补充剂用于农业，并且符合美国环境保护局（EPA）标准（联邦法规汇编第40篇第503部分）中的A类污泥指标。
