Study on Technical Schemes for Major Pollutants Emission Reduction in Beijing North Canal River Basin Based on Watershed Water Quality Target Management

Water quality target management in watershed is the fundamental choice of city rivers suffering both serious pollution and severe water shortage. In this study, we performed a case study regarding river pollution control plan based on water quality target management in the North Canal River catchment of Beijing section, in order to obtain effective water quality improvement programs. The ammonia nitrogen (NH3-N) and chemical oxygen demand (COD) were taken as the main controlling pollutants. Water quality targets and basic water quality improvement scenarios were set up considering different intensities of population regulation scenarios and gradually strengthening emission control measures. The MIKE11 model was adopted to simulate the effects of a range of water quality improvement scenarios. Results indicated that the basic scenarios could dramatically improve the surface water environment. However, additional intensive and combined measure programs should be implemented to ensure that the water quality would basically meet the targets of corresponding water function zones. The results highlight the need to implement water conservation in water shortage urban river basin and show the importance of enhancing drainage communication and conducting ecological water replenishment in such kind basins. It is expected to provide a reference for the water environment management practice of other metropolis in the world facing both crisis of water resource shortage and water environment pollution.

Socioeconomic drivers of the human microbiome footprint in global sewage

The human microbiome leaves a legacy in sewage ecosystems,also referred to as the human sewage microbiomes(HSM),and could cause potential risk to human health and ecosystem service.However,these host-associated communities remain understudied,especially at a global scale,regarding microbial diversity,community composition and the underlying drivers.Here,we built a metagenomic read mapping-based framework to estimate HSM abundance in 243 sewage samples from 60 countries across seven continents.Our approach revealed that 95.03%of human microbiome species were identified from global sewage,demonstrating the potential of sewage as a lens to explore these human-associated microbes while bypassing the limitations of human privacy concerns.We identified significant biogeographic patterns for the HSM community,with species richness increasing toward high latitudes and composition showing a distance-decay relationship at a global scale.Interestingly,the HSM communities were mainly clustered by continent,with those from Europe and North America being separated from Asia and Africa.Furthermore,global HSM diversity was shown to be shaped by both climate and socioeconomic variables.Specifically,the average annual temperature was identified as the most important factor for species richness(33.18%),whereas economic variables such as country export in goods and services contributed the most to the variation in community composition(27.53%).Economic and other socioeconomic variables,such as education,were demonstrated to have direct effects on the HSM,as indicated by structural equation modeling.Our study provides the global biogeography of human sewage microbiomes and highlights the economy as an important socioeconomic factor driving host-associated community composition.