Anaerobic co-digestion of dairy manure (DM) and concentrated food processing wastes (FPW) under thermophilic (55 °C) and mesophilic (35 °C) temperatures, and fertilizer value of the effluent were investigated in this study. Two types of influent feedstock were utilized: 100 % DM and a 7:3 mixture (wet weight basis) of DM and FPW. The contents of the FPW, as feedstock were 3:3:3:1 mixture of cheese whey, animal blood, used cooking oil and residue of fried potato. Four continuous digestion experiments were carried out in 10 L digesters. Co-digestion under thermophilic temperature increased methane production per digester volume. However, co-digestion at 35 °C was inhibited. Total Kjeldahl nitrogen (N) recovered after digestion ranged from 73.1 to 91.9 %, while recoveries of ammonium nitrogen (NH4-N) exceeded 100 %. The high recovery of NH4-N was attributed to mineralization of influent organic N. The mixture of DM and FPW showed greater recoveries of NH4-N after digestion compared to DM only, reflecting its greater organic N degradability. The ratios of extractable to total calcium, phosphorus and magnesium were slightly reduced after digestion. These results indicate that co-digestion of DM and FPW under thermophilic temperature enhances methane production and offers additional benefit of organic fertilizer creation. 相似文献
Tropical estuary wetlands are important for aquaculture and wildlife. However, many of them receive large amounts of anthropogenic heavy metals annually. Here, the transformation of spiked heavy metals, namely, Cd, Cr, Cu, Ni, Pb, and Zn, and the effects of salinity on their transformation in wetland soils after an eight-month-long incubation under moisture-saturation conditions were studied in the Pearl River estuary in China. Cd exhibited high mobility and bioavailability, with 12.2% to 25% Cd existing in the exchangeable fraction. Other heavy metals primarily existed in the reducible and oxidisable forms, and less than 2% were bound to the exchangeable fraction. Compared with the controls, contents of none of the metals associated with residual forms were significantly altered. These results imply that most exchangeable metals, except for Cd, transformed into other stable fractions through an eight-month-long ageing process, but not into the residual fraction. Thus, transformation from non-residual to residual forms was very slow in the tropical estuary wetland environment. Addition of NaCl increased the exchangeable fractions of Cd, Pb, and Zn, suggesting that increased soil salinity induced by flood tides during the dry season may enhance their mobility. 相似文献
In this study, we added increments of acid and base to three calcareous soils from the eastern, middle and western parts of Gansu Province (China) and to three treated soils to remove calcium carbonate, organic matter and both carbonate and organic matter, respectively. the titration curves were measured and the magnitudes of buffer capacities as a function of pH were computed. It was found that the buffer capacity of calcareous soil is mainly attributed to calcium carbonate, as expected from the chemical composition of calcareous soil, while cation exchange system, silicate buffer system and organic matter play a minor role. the results clearly show that these soils of Gansu Province will not become a problem in the near future from the entrance of H+ into these soils. 相似文献
This article developed a decomposition model of energy productivity on the basis of the economic growth model. Four factors were considered which may influence China’s energy productivity according to this model: technology improvement, resource allocation structure, industrial structure and institute arrangement. Then, an econometric model was employed to test the four factors empirically on the basis of China’s statistical data from 1978 to 2004. Results indicated that capital deepening con- tributes the most (207%) to energy efficiency improvement, and impact from labor forces (13%) is the weakest one in resource factor; industrial structure (7%) and institute innovation (9.5%) positively improve the energy productivity. 相似文献
The cover image is based on the Original Article Noninvasive prenatal paternity testing by means of SNP-based targeted sequencing by Jacqueline Chor Wing Tam et al., https://doi.org/10.1002/pd.5595 .