The paper aims at providing a framework to calculate the agro-eco-compensation standard based on the systems agro-ecological concept of embodied energy as emergy. We have proposed a calculation system of eco-compensation standard for sustainable agricultural development based on the convertibility between emergy and price. According to our calculation, the total energy of agricultural production in Yongding River Basin was 3.45 E + 16 Sej/ha (the unit emergy value, expressed in solar emergy joules per unit) in terms of the renewable resources, nonrenewable resources, material inputs, and service costs. The energy of renewable and nonrenewable resources was 1.59 E + 16 and 1.86E + 16 Sej/ha, respectively. The ESI (environmental sustainability index) of the study area was 0.1056, indicating that its agricultural production was in a seriously unsustainable condition. To realize the sustainable agricultural production in the watershed, the downstream governments should pay $21.81 M (¥135 million) approximately to upstream governments for water and soil conservation. The results of the present study suggested that the emergy-based calculation method of agro-eco-compensation standard is feasible to a certain degree.
Water-borne typhus, dysentery, viral hepatitis, diarrhoea, and other intestinal infectious diseases are the prevailing diseases in the rural areas in China. The harvested rainwater is easily contaminated by air pollution, surface runoff fertilizer and pesticides, solid waste and chips at the rainwater-harvesting surface (rubbish, animal faeces, etc.), and anthropogenic pollution. With the development of technology, products made of ceramic filters have been widely used in cities where tapwater is available. However, as a drawback, ceramic filters do not apply to those rural singlehousehold families without access to water pressure. In addition, the filter has a certain service life, and it has to be frequently replaced if water quality is poor, which will burden water users with unbearable costs.
There have been many studies on single strains in wastewater treatment and a new synthetic microbial community was prepared in this study, which provides a reference for the application of heterotrophic nitrification-aerobic denitrification in actual wastewater treatment. The growth period distribution of the composite bacteria was determined by plotting growth curves with different sole nitrogen sources, and the influence of the carbon source, carbon to nitrogen ratio (C/N) ratio, pH, and temperature on ammonia removal by the composite heterotrophic nitrifying-aerobic denitrifying strain was investigated. The optimal conditions for the heterotrophic nitrification process were sodium citrate as the carbon source, a C/N ratio of 10, a pH of 7, and a temperature of 30 °C, and only trace amounts of nitrate and nitrite were observed during the process. When the sequencing batch reactor (SBR) of a pig farm wastewater treatment plant was inoculated with the synthetic microbial community, the average removals of the chemical oxygen demand (COD) and ammonia nitrogen in the effluent were 92.61% and 20.56%, respectively. From the results, the synthetic microbial community was able to simultaneously perform heterotrophic nitrification-aerobic denitrification indicating great potential for full-scale applications.
In China, rural domestic sewage treatment has become an urgent problem to be solved to improve the rural human settlement environment. However, there is no scientific, objective, and systematic evaluation model for selecting rural domestic sewage treatment technology. Therefore, this paper mainly studies on the establishment of the evaluation system model of China's typical rural domestic sewage treatment technology and the application of technology selection. Based on the analytic hierarchy process and the life cycle method, the experts consulted and analyzed the factors affecting the evaluation of China's rural sewage treatment technology. The comprehensive evaluation index system suitable for China's rural sewage treatment technology was established based on the analysis results. Combined with the fuzzy comprehensive evaluation method, five typical rural domestic sewage treatment technologies were applied and analyzed. The results show that the comprehensive evaluation of the biofilm technology is the best at 3.5669, followed by the septic tank treatment technology and land treatment technology, which are 2.8829 and 2.8422, respectively. The case analysis verifies the applicability of the model, which can support the selection of technologies for the rural domestic sewage treatment market in China.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.