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The effect of hydraulic retention time (HRT) and influent alkalinity on the performance of bio-electrochemical system assisted anaerobic baffled reactor (BES-ABR) was investigated in this study. The results indicated that as the HRT and influent alkalinity increase, COD removal efficiencies were enhanced correspondingly. The maximum COD removal efficiency of 97.4% was obtained at HRT of 48 h and COD of 4,000 mg/L. The maximum COD removal efficiency of 87.5% was obtained at influent alkalinity of 1,300 mg CaCO3/L and COD of 5,000 mg/L. Analysis of microbial community suggested that electrogenic micro-organisms were responsible for the better performance and stability of the system. The establishment and performance of this novel and efficient partial two-phase separation of BES-ABR strongly depended on the regulation of HRT and influent alkalinity.

Arbuscular mycorrhizal fungi (AMF) are widespread in terrestrial ecosystems. In addition to their contributions to plant nutrient uptake, AMF also provide many ecological functions including regulation of soil C dynamics. However, both stimulating and retarding soil organic decomposition by AMF have been observed. Here we discuss the possible reasons for such a contradiction. Arbuscular mycorrhizal fungi contribute to soil aggregation mainly through hyphal enmeshment, saprotrophic suppression, and production of glomalin-related soil proteins, while AMF can also stimulate organic decomposition through promoting degradative enzymes, modifying root production and activity, and/or through regulating the microbial community in the mycorrhizosphere and hyphosphere. The role of AMF in C decomposition is strongly dependent on the quality and quantity of different soil C pools. Arbuscular mycorrhizal fungi can stimulate fresh residue decomposition initially through stimulating the decomposition of fresh residues (particularly those having high C/N ratio), whereas for older or decomposed soil organic C, AMF tend to suppress decomposition by promoting soil aggregation. Under elevated CO2 (eCO(2)), AMF show additive effects on residue decomposition, priming effects, and changes in soil a regation. Despite organic decomposition rates differing in the short term and long term following litter experiments, our discussion highlights the role of AMF in organic C dynamics. We hypothesize that AMF would benefit soil C gain in the long term and thereby predict that disturbances that impacts negatively on AMF, such as tillage, residue burning, fertilization, and fungicide application, would lead to soil C decline particularly under eCO(2).

Capacitive voltage transformer (CVT) is composed by a capacitive divider unit and an electromagnetic unit. In order to simulate CVT's performance, it is necessary to establish the equivalent model of CVT and obtain all the equivalent parameters. The equivalent parameters of the capacitive voltage divider unit can be measured; however, the electromagnetic unit is a sealed chamber, and its parameters are hard to obtain directly. The paper proposes a 220kV CVT circuit model incorporates divider insulation parameters, and the CVT measurement errors under different loads are obtained by the load error characteristic test. For the electromagnetic model is fixed and parameters are uncertain, the load error data is fitted by the genetic algorithm and LM algorithm. The equivalent electrical parameters of CVT electromagnetic unit are obtained, and the equivalent CVT circuit model is constructed by combining the parameters of the capacitive voltage divider.

In this study, a new process was proposed to enhance the stability and efficiency of an anaerobic baffled reactor (ABR). The process was examined in a four equal compartments ABR with total volume of 3.46 L. The first compartment was operated for fermentative hydrogen production and the last three compartments were used as continuous singer chamber microbial electrolysis cells (MECs) for methanogenesis. The system was operated at 35 ± 1 °C and hydraulic retention time (HRT) of 24 h with influent chemical oxygen demand (COD) concentration of 3500 mg/L–4000 mg/L. The results indicated that the proportion of hydrogen in the first compartment was 20.7% and proportions of methane in the last three compartments were 98.0%, 93.6% and 70.1%, respectively. A total of 98.0% of COD removal rate was achieved as well. Hence, this new system has following advantages: hydrogen production with cleaner effluent, high COD removal rate, and net methane production for practical use.