Gaur Rubia Zahid, Khan Abid Ali, Suthar Surindra
School of Environment & Natural Resources, Doon University, Dehradun 248001, India.
Department of Civil Engineering, Jamia Millia Islamia, New Delhi 110025, India.
Chemosphere. 2017 May;174:754-763. doi: 10.1016/j.chemosphere.2017.01.133. Epub 2017 Jan 30.
The duckweeds (DW) are considered as a major problem in tropical aquatic system as they grow very fast and produce enormous rich-biomass, which can be harvested for renewable energy operations. But complex lignocellulosic compounds limit their utility in process like anaerobic digestion. This batch study aimed to analyse characteristics (proximate, ultimate and physico-chemical) and possible utility of DW for anaerobic co-digestion with waste activated sludge (WAS) under mesophilic conditions for 35 d. Two sets of experiment were tested: substrate with and without thermal pre-treatment. Five combinations of DW: WAS (70:20, 60:20, 50:20, 40:20 and 30:20%) were established and biomethanation along with changes in pH, volatile solids (VS), volatile fatty acids (VFAs), and soluble chemical oxygen demand (sCOD) of digestate were recorded. The total CH yield (mL CH g VS) ranged between 60 and 468 for pre-treated, and 9 and 76 for non-pre-treated. The maximum CH yield was 468 mL CHg VS in DW: WAS (50:20). Thermally treated setups, showed about 13-, 24.1-, 21.1-, 1.4-, and 2.3-fold higher CH than non-treated setups. The treated mixtures showed high reduction of COD (>41-96) and VS (>59-98%) in co-digesters. The high degree of Gompertz curve fitting (R > 0.99) has suggested pre-treatment of substrate for optimal outputs of co-digester. Based on results obtained, it is suggested that DW (50-60% in digester) can be used as renewable energy resource for biomethanation process after thermal pre-treatment.
浮萍（DW）在热带水生系统中被视为一个主要问题，因为它们生长迅速，能产生大量丰富的生物质，这些生物质可用于可再生能源生产。但复杂的木质纤维素化合物限制了它们在厌氧消化等过程中的应用。本批次研究旨在分析浮萍的特性（近似、最终和物理化学特性）以及在中温条件下与废弃活性污泥（WAS）进行厌氧共消化35天的潜在用途。进行了两组实验：有热预处理和无热预处理的底物。建立了浮萍与废弃活性污泥的五种组合（70:20、60:20、50:20、40:20和30:20%），记录了生物甲烷化过程以及消化液的pH值、挥发性固体（VS）、挥发性脂肪酸（VFA）和可溶性化学需氧量（sCOD）的变化。预处理后的总甲烷产量（mL CH g VS）在60至468之间，未预处理的在9至76之间。在浮萍:废弃活性污泥（50:20）中，最大甲烷产量为468 mL CHg VS。热处理的装置显示出比未处理的装置高出约13倍、24.1倍、21.1倍、1.4倍和2.3倍的甲烷产量。处理后的混合物在共消化器中显示出较高的化学需氧量降低率（>41 - 96）和挥发性固体降低率（>59 - 98%）。高度的Gompertz曲线拟合（R > 0.99）表明对底物进行预处理可实现共消化器的最佳输出。根据所得结果，建议在热预处理后，浮萍（消化器中占50 - 60%）可作为生物甲烷化过程的可再生能源资源。
