Department of Environmental Health Engineering, Shiraz University of Medical Science, Shiraz, Iran.
Department of Environmental Health, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Environ Sci Pollut Res Int. 2019 Dec;26(35):35757-35766. doi: 10.1007/s11356-019-06618-5. Epub 2019 Nov 7.
Composting is one of the environmentally desirable methods for the management of sewage sludge. In this process, the organic matters were decomposed by microorganisms. However, different treatments can improve their qualities. This study aimed to investigate the effect of two agricultural waste wheat straw (WS) and green waste eucalyptus tree leaves (ETL) treatments on the quality of the compost produced from dewatered sewage sludge. So that, the variation trend of heavy metals, temperature, moisture, PH, and C/N ratio was considered during the composting process. The results showed that the variation of some parameters in WS and ETL such as temperature (24.68 ± 0.26 and 23.41 ± 1.35), moisture (4.5 ± 2.64 and 7.66 ± 2.51), pH (5.66 ± 0.35 and 5.97 ± 0.41), and C/N ratio (250 ± 4.08 and 60 ± 3.21) was suitable in both windrows, respectively. Likewise, trend of mineralization was suitable in both masses, because TVS (43 to 78 mg/g DW for WS and 45 to 69 mg/g DW for ETL) and TDS (21 to 55 mg/g DW for WS and 2.6 to 38 mg/g DW for ETL) decreased and increased, respectively, in the composting process. While fecal coliform (2.72 MPN/g DW) and EC (2.4mmho/cm) at WS was more than Iran's agricultural standard. As a consequence, although the quality of both masses was suitable and similar, there are some limitations for using treated compost by WS in agricultural lands due to higher levels of EC, fecal coliforms, and manganese. Therefore, quality of dewatered sludge treated compared with ETL is higher than WS. Furthermore, improvement process and application of some pretreatments are necessary for decreasing the heavy metals.
堆肥是一种理想的污水处理污泥管理方法。在这个过程中，有机物被微生物分解。然而，不同的处理方法可以改善它们的质量。本研究旨在探讨两种农业废弃物小麦秸秆（WS）和桉树叶（ETL）处理对脱水污泥所制堆肥质量的影响。因此，在堆肥过程中考虑了重金属、温度、水分、pH 值和 C/N 比的变化趋势。结果表明，WS 和 ETL 中一些参数的变化，如温度（24.68±0.26 和 23.41±1.35）、水分（4.5±2.64 和 7.66±2.51）、pH 值（5.66±0.35 和 5.97±0.41）和 C/N 比（250±4.08 和 60±3.21）在各自的垄中均适宜。同样，矿物质化趋势在两种堆肥中均适宜，因为 TVS（WS 为 43 至 78mg/g DW，ETL 为 45 至 69mg/g DW）和 TDS（WS 为 21 至 55mg/g DW，ETL 为 2.6 至 38mg/g DW）在堆肥过程中分别减少和增加。然而，WS 中的粪大肠菌群（2.72 MPN/g DW）和 EC（2.4mmho/cm）高于伊朗农业标准。因此，尽管两种堆肥的质量均适宜且相似，但由于 EC、粪大肠菌群和锰的含量较高，WS 处理后的堆肥在农业用地中的应用存在一些限制。因此，与 WS 相比，脱水污泥经 ETL 处理后的质量更高。此外，为了降低重金属含量，需要对预处理过程进行改进和应用。
