餐饮废水的化学处理方法研究

以聚硅酸铝为混凝剂,用化学法絮凝处理餐饮废水。考查了酸度、混凝剂加入量、搅拌速度、搅拌时间、沉降时间对CODCr去除率的影响。结果表明酸度在pH9～11范围内,每100mL污水中聚硅酸铝加入量为02mL,搅拌速度为45r/min,搅拌15s,沉降15min后,测上清液的化学耗氧量,CODCr去除率可达88%左右。该方法效果好、工艺简单、易于操作管理,有实际应用价值。     

Land use change simulation and spatial analysis of ecosystem service value in Shijiazhuang under multi-scenarios

Environmental Science and Pollution Research - Simulating changes in the value of ecosystem services caused by land use changes in large cities under multiple scenarios is of great significance for...     

Market segmentation and industry overcapacity considering input resources and environmental costs through the lens of governmental intervention

Environmental Science and Pollution Research - The problems with China’s regional industrial overcapacity are often influenced by local governments. This study constructs a framework that...     

Estimation of crop residue in China based on a Monte Carlo analysis

Accurate crop residue resource estimation is important for bioenergy development.This is done by the ratio of residue to grain(R/G),which is usually regarded constant and is widely used for crop residue estimation though uncertainty is inevitable in practice.In this study,a Monte Carlo algorithm was applied to estimate national crop residue by R/G taken from published reports in China.The estimated result was further mapped in pixels by geographic information system.In2009,the amount of crop residue was found to be 802.32 million tons(Mt),with 679.36 and 947.28 Mt as the lower and upper limits for 95%confidence limits.Chinese crop residue was dominated by rice,wheat,and corn,accounting for74.57%(598.29 Mt).From 1949 to 2009,the amount of crop residue increased by four times,accompanied by component change.The spatial distribution of crop residue in China is markedly heterogeneous.Compared to the shortage of crop residue in northwest China,there is an abundant crop residue of about 334 Mt in eastern China,attracting 90%of the country's electricity or heat generation plants.     

黄土边坡坡面冲刷的临界坡度

边坡坡面冲刷存在一个临界坡度,边坡坡度接近临界坡度,冲刷量最大。通过能量守恒原理,建立了临界坡度的计算公式,它与边坡坡长以及降雨强度和坡面的粗造程度存在一定的函数关系。通过实例分析了临界坡度和单级坡高的确定,理论分析与工程实践基本一致,说明理论分析是合理可行的。     

Distribution,bioavailability, and potential ecological risk of Cu,Pb, and Zn in soil in a potential groundwater source area

In this study, we examined three horizontal and vertical soil profiles along a sewage drainage ditch in order to determine the spatial distribution of Cu, Pb, and Zn in soils and to assess the bioavailability and potential ecological risks associated with these metals in a potential groundwater source area. Results showed that the concentrations of Cu, Pb, and Zn were approximately at background level, suggesting that human activities (industrial and agricultural pollution) had a negligible influence on these metals in soil, and that the concentrations reflected the natural background levels in the study area. Cu, Pb, and Zn concentrations were slightly higher in topsoil (0–20 cm) than deeper in the soil profile. Using a modified BCR sequential extraction method to evaluate the mobility and bioavailability of metals showed that the potential bioavailability sequence of Cu, Pb, and Zn at three depths in the soil profile was in the order Cu?≈?Pb?<?Zn. The potential ecological risk from the metals was evaluated using risk assessment code, and the results suggest that Cu and Zn pose no or low risk, while there is a low or medium risk from Pb. Results from groundwater monitoring showed that the groundwater was not polluted by leaching from soil.     

Does the promotion pressure on local officials matter for regional carbon emissions? Evidence based on provincial-level leaders in China

Environmental Geochemistry and Health - This paper constructs data from 30 provinces in mainland China from 1997 to 2016 and mainly adopts panel data fixed effects models to investigate how the...     

北京冬季奥运会历史同期大气PM2.5污染特征分析

基于2015~2021年的1~3月北京市大气PM_2.5浓度与化学组成长期观测数据,分析了2022年北京冬季奥林匹克运动会（冬奥会）和北京冬季残疾人奥林匹克运动会（冬季残奥会）历史同期的PM_2.5污染态势、化学组成特征以及潜在源区.2015~2018年的1~3月重污染［日均ρ（PM_2.5）>75 μg·m^-3］天数以及重污染期间PM_2.5平均值下降十分显著,之后这两者未发生明显改变.2018~2021年的1~3月每年平均发生重污染23 d,重污染天ρ（PM_2.5）平均值约为120.0 μg·m^-3.2015~2021年的1~3月超长重污染过程（连续重污染超过5 d）平均每年发生2~3次,其中2021年发生3次,且持续时间最长达到8 d.历年冬奥会历史同期发生重污染的天数为2~9 d,春节期间烟花爆竹大量燃放可能是该时期重污染发生的重要原因之一;冬季残奥会历史同期重污染天数一般为1~5 d,但2021年受频繁出现的静稳天气影响,重污染天数高达9 d.在同时段重污染期间,PM_2.5化学组成均以二次组分为主,例如在PM_2.5可测组分中,2020年NO₃^-质量分数高达46%,较同年清洁天（11%）显著增加;SO₄^2-质量分数为12%~19%,说明当前硫酸盐污染仍不容忽视.北京市1~3月PM_2.5主要贡献区域包括内蒙古自治区中西部、河北省、天津市、山西省、陕西省、山东省中西部和河南省北部.研究结果将为北京市冬季空气质量持续改善以及2022年冬奥会与冬季残奥会期间北京市环境空气质量保障提供科学依据.