Nitrogen removal from landfill leachate via ex situ nitrification and sequential in situ denitrification

Ex situ nitrification and sequential in situ denitrification represents a novel approach to nitrogen management at landfills. Simultaneous ammonia and organics removal was achieved in a continuous stirred tank reactor (CSTR). The results showed that the maximum nitrogen loading rate (NLR) and the maximum organic loading rate (OLR) was 0.65 g N l^?1 d^?1 and 3.84 g COD l^?1 d^?1, respectively. The ammonia and chemical oxygen demand (COD) removal was over 99% and 57%, respectively. In the run of the CSTR, free ammonia (FA) inhibition and low dissolved oxygen (DO) were found to be key factors affecting nitrite accumulation. In situ denitrification was studied in a municipal solid waste (MSW) column by recalculating nitrified leachate from CSTR. The decomposition of MSW was accelerated by the recirculation of nitrified leachate. Complete reduction of total oxidized nitrogen (TON) was obtained with maximum TON loading of 28.6 g N t^?1 TS d^?1 and denitrification was the main reaction responsible. Additionally, methanogenesis inhibition was observed while TON loading was over 11.4 g N t^?1 TS d^?1 and the inhibition was enhanced with the increase of TON loading.     

一起预制板脆性断裂事件的原因及预防

对发生在该钢铁厂的一起预制板脆性断裂事件进行了介绍和分析,探讨了在高温条件下发生断裂的原因。     

工业有毒物质防治的技术措施

简要介绍了几种毒物防治的技术措施。     

Externalities, Floating Population and Spatial Agglomeration

With the further development of socialist market economy, the mobility of factor markets in China, especially the labor market, is strengthened. Externalities interacts with the agglomeration of productive factors. Under the framework of new economic geography, this article presents a theoretical model involving the endogenous population density affected by urban externalities. Results show that the population density is more concentrated around the center because the degree and extent of interaction between individuals intensifies when the distance from the center decreases. When there are several externalities resources, the aggregation of externalities changes the configuration of spatial factor allocation. These results fit well with the empirical facts about the decreasing density of floating population along the cities of Guangzhou, Dongguan and Shenzhen in Guangdong Province which is situated in the eastern coast of the Pearl River Delta. We fred that under the impacts of externalities released from Hong Kong into the coast, floating population was more concentrated around Shenzhen and Dongguan, which are more adjacent to Hong Kong compared with Guangzhou City.     

火力发电厂安全现状评价模式探讨

以火电厂现状评价为例,探索火力发电厂安全现状评价模式。     

发达与欠发达地区耕地保护行为中的利益机制分析

本文从当前发达与欠发达地区耕地保护上的利益矛盾入手，以它们之间的内在经济关系为基础，运用局部均衡分析方法，构建了一个简单的经济模型，对上述矛盾“零和博弈”的长期效应进行了揭示，并讨论了消除这种不良影响的政策或制度安排。