Atilla Beyza, Yangin-Gomec Cigdem, Altinbas Mahmut, Ozturk Izzet
Department of Environmental Engineering, Faculty of Civil Engineering, Istanbul Technical University, Maslak, Istanbul, Turkey.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2003;38(10):2369-79. doi: 10.1081/ese-120023416.
The performance of anaerobic digestion of municipal sludge having high inorganic solid/silt in Tuzla Wastewater Treatment Plant (TWWTP) in Istanbul was evaluated using granular seed. High silt/solid content is the main problem related to wastewater collection system in TWWTP. Due to high TSS concentration of the influent, inorganic solid ratio reaches to 60-70% in the primary sludge that makes sludge digestion very difficult. The aim of this study was to evaluate the detrimental effects of inorganic silt/clay on anaerobic sludge solubilization of the primary sludge (PS), of the biological sludge (BS), and of the mixed sludge (50%PS + 50%BS). Anaerobic solubilization was carried out in continuously stirred anaerobic reactors at mesophilic temperature (35 degrees C). Results indicated significant total biogas productions in all reactors during digestion period. The biogas production of the primary sludge was higher than the biogas productions of the mixed sludge and the biological sludge. The methane contents of the primary, biological. and mixed sludges were found as around 72, 78, and 75%, respectively. When all types of sludges were used as substrates, the reactors removed VSS with a corresponding production of Soluble COD (SCOD). The greatest degree of hydrolysis/acidogenesis was observed in all types of sludges in about 10 days of operation and became almost stable which indicated that the reactors were still in the hydrolysis/acidogenesis phase. VFAs measurements were well matched with SCOD results. In all reactors, observation of the conversion into methanogenic phase in about 1.5 month was not possible which might be attributed to high inorganic silt/clay and salinity content of TWWTP. High inorganic silt/clay and salinity might have decreased the biodegradability of all sludges and methanogenesis could not operate in early periods of digestion. Higher SCOD decreases might have been possible if longer treatment time and more optimal conditions for anaerobic solubilization were applied. The pH did not fall below the unfavorable range in all reactors during the study.
利用颗粒种子对伊斯坦布尔图兹拉污水处理厂（TWWTP）中无机固体/淤泥含量高的城市污泥厌氧消化性能进行了评估。高淤泥/固体含量是TWWTP废水收集系统的主要问题。由于进水的总悬浮固体（TSS）浓度高，初级污泥中的无机固体比例达到60 - 70%，这使得污泥消化非常困难。本研究的目的是评估无机淤泥/粘土对初级污泥（PS）、生物污泥（BS）和混合污泥（50%PS + 50%BS）厌氧污泥溶解的有害影响。厌氧溶解在中温（35℃）的连续搅拌厌氧反应器中进行。结果表明，在消化期间所有反应器中均产生了大量的沼气。初级污泥的沼气产量高于混合污泥和生物污泥的沼气产量。初级、生物和混合污泥的甲烷含量分别约为72%、78%和75%。当所有类型的污泥用作底物时，反应器去除挥发性悬浮固体（VSS）并相应产生可溶性化学需氧量（SCOD）。在运行约10天时，在所有类型的污泥中观察到最大程度的水解/酸化作用，并且几乎变得稳定，这表明反应器仍处于水解/酸化阶段。挥发性脂肪酸（VFAs）的测量结果与SCOD结果非常匹配。在所有反应器中，大约1.5个月内都不可能观察到转化为产甲烷阶段，这可能归因于TWWTP中高无机淤泥/粘土和盐度含量。高无机淤泥/粘土和盐度可能降低了所有污泥的生物降解性，并且在消化早期产甲烷作用无法进行。如果应用更长的处理时间和更优化的厌氧溶解条件，可能会有更高的SCOD降低。在研究期间，所有反应器中的pH均未降至不利范围以下。
