Institute of Water Research, Department of Microbiology. University of Granada. Ramón Cajal nº 4, 18071 Granada, Spain.
University of Cordoba (Spain) - Department of Inorganic Chemistry and Chemical Engineering. Campus Universitario de Rabanales. Carretera N-IV, km 396, Edificio Marie Curie, 14071 Córdoba, Spain.
Environ Res. 2019 Oct;177:108624. doi: 10.1016/j.envres.2019.108624. Epub 2019 Aug 2.
In the present study, physico-chemical characteristics, heavy metals content, odour emissions, microbial enumeration and enzymatic activities were analysed during industrial scale composting of sewage sludge partially pre-treated to evaluate the effect of a combined system of semi-permeable film and aeration on these parameters. The results related to physico-chemical parameters showed a decrease in total organic carbon (TOC), organic matter (OM), total carbon (TC) along the process. Volatile solids (VS) were also reduced, reaching 36% at 120 days, which is above the limit according to the current legislation. Similarly, metal content was found to be an important variable in the evolution of enzymatic activity, while lead (Pb), zinc (Zn), and nickel (Ni) were the most influential. Moreover, heavy metals were found below the limit of type B compost quality or European class 2 at the end of the process, which is suitable for agriculture soil. The odorous impact generated during the hydrolytic stage was reduced to an average value of 4 ou/s. This suggests that, covered stage with the semi-permeable film, could be a viable solution to mitigate odour emissions. The highest temperature was reached at 10 days and it was favoured by semi-permeable film. Temperature promoted the presence of thermophilic bacteria and fungi and indicated an early biodegradation process mediated by microorganisms. Statistical analyses revealed a high correlation of physico-chemical variables with microbial activity. Thus, samples from the first 14 days were highly correlated with enzymatic activities such as β-glucosidase (Ac-βGlu), protease (Ac-Pr), and dehydrogenase (Ac-De), which have usually been involved in the hydrolysis of organic matter.
在本研究中，对部分预处理的污水污泥进行工业规模堆肥，分析了物理化学特性、重金属含量、气味排放、微生物计数和酶活性，以评估半渗透膜和曝气联合系统对这些参数的影响。与物理化学参数相关的结果表明，总有机碳（TOC）、有机质（OM）和总碳（TC）在整个过程中减少。挥发性固体（VS）也减少了，在 120 天时达到 36%，高于现行法规规定的限值。同样，金属含量是酶活性演变的一个重要变量，而铅（Pb）、锌（Zn）和镍（Ni）的影响最大。此外，在过程结束时，重金属含量低于 B 类堆肥质量或欧洲 2 级的限值，适用于农业土壤。水解阶段产生的臭味影响平均降低到 4 个臭味单位/秒。这表明，覆盖半渗透膜的阶段可能是减轻气味排放的可行解决方案。最高温度在第 10 天达到，并且受到半渗透膜的促进。温度促进了嗜热细菌和真菌的存在，并表明微生物介导的早期生物降解过程。统计分析显示，物理化学变量与微生物活性高度相关。因此，第 14 天之前的样品与 β-葡萄糖苷酶（Ac-βGlu）、蛋白酶（Ac-Pr）和脱氢酶（Ac-De）等酶活性高度相关，这些酶通常参与有机物的水解。
