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This article explained the definition and attribute of municipal sludge in Beijing, analyzed the production and discharge characteristics and studied the development course of disposal and utilization of municipal sludge in Beijing. The results show that the development of Beijing municipal sludge disposal and utilization mainly includes three stages, the first stage before 1999, started sludge drying and stumping fertilizer; the second stage from 1999 to 2012,the slow development stage of disposal and utilization, the demonstration plant of sludge treatment was established, using various drying technologies and incineration treatment modes; the third stage is from 2012 to now, the sludge treatment technology in the central district of city is the advanced anaerobic digestion of thermal hydrolysis, and the disposal mode is mainly land use, forming a typical Gao Antun sludge treatment mode. On the basis of the current situation of municipal sludge treatment in Beijing, this paper summarizes relevant policies and technical standards of sludge treatment in Beijing, and introduces the new progress of low-carbon and green transformation of municipal sludge disposal in Beijing which provides certain reference and reference for the treatment and disposal of municipal sludge. [ABSTRACT FROM AUTHOR]

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The evaluation of arable land quality is one of the important means to protect and manage arable land. In order to meet the needs of current arable land management work and protect the safety of national arable land resources, it is necessary to establish an arable land quality index system to evaluate the arable land quality. Based on the change of human demand for arable land resources, the components of arable land use system and the relationship between various components of arable land use system, this paper systematically expounded the theoretical framework of arable land quality evaluation，and the evaluation index system of arable land quality was established by the matching of different demand hierarchy characteristics of human and supply of arable land resources. The evaluation index system of arable land quality consisted of five dimensions: geology characteristics, soil traits, farming conditions, health status of arable land and biological characteristics of arable land. According to the different characteristics of each dimension of arable land quality, suitable evaluation methods were selected. The three dimensions of geology characteristics, soil traits and farming conditions were calculated by using the weighted additive. The health status of arable land is calculated by the “1+X” cumulative model; the biological characteristics of arable land were calculated by coefficients. Then, the quality of arable land for high yield and high efficiency demand was evaluated by the method of additive, and the quality of arable land for green health and sustainable development was evaluated by the method of revised. The quality of arable land in Daxing District of Beijing was evaluated by using multi-source and multi-scale data. The results showed that the evaluation results of arable land quality in Daxing District were divided into five grades at equal intervals of 20 points. The arable land quality index [80,100] was excellent, [60, 80) was good, [40, 60) was medium, [20, 40) was lower, and [0, 20) was poor. Under the conditions of high yield and high efficiency, the excellent area accounted for 88.27% of the total arable land, the good accounted for 11.73%. Under the condition of green health demand, the excellent accounted for 73.61% of the total arable land, and the good accounted for 26.39%. Under the conditions of sustainable development demand, the excellent accounted for 3.03% of the total arable land, and the good accounted for 52.30%, medium accounted for 40.39%, and lower accounted for 4.27%. From the perspective of space, the results of arable land quality evaluation of high yield, high efficiency, green health and sustainable development demand were all high in the east and low in the west. By comparing the results of arable land quality evaluation under different demand conditions, the area of arable land in excellent is decreasing, while the area of arable land in good, medium and lower is increasing. The health status of arable land and the biological characteristics of arable land have become important factors affecting the quality improvement of arable land. Research conclusions are that the evaluation index system of arable land quality based on sustainable development demand can provide effective support for the evaluation and management of arable land, and is more in line with the national quantity, quality and ecological management needs of arable land. [ABSTRACT FROM AUTHOR]