Multifunctional rural transition along China’s Yangtze River Transect: Spatial differentiation and economic relevance

Environmental Science and Pollution Research - To understand rural sustainability, it is necessary to scrutinize the relationship between rural transition and economic growth. The article uses...     

NO2 catalytic formation,consumption, and efflux in various types of diesel particulate filter

Environmental Science and Pollution Research - The high NO2/NOX ratio in the after-treatment system is beneficial to its performance and achieved by NO catalytic conversion in diesel oxidation...     

山东省临沂市土壤有机氯农药滴滴涕残留量与空间分布特征

通过对临沂市全区表层土壤每36 km2进行样品收集,测试分析了DDTs、Org C、N等指标,主要研究了区域表层土壤DDTs的残留现状、组成和来源、影响因素、空间分布和环境质量特征.结果表明,调查区表层土壤中DDTs检出率为71.75%,平均含量为0.035μg·g-1;检出样品中p,p'-DDT和p,p'-DDE为主要残留物,平均残留分别为0.033μg·g-1和0.010μg·g-1,分别占检出样的60.99%和34.62%.DDTs降解率指示区域58%表层土壤为新近输入区,新近输入区在调查区中南部分布尤为明显;而p,p'-DDD/p,p'-DDE指示区域DDTs降解以氧化环境为主,o,p'-DDT/p,p'-DDT指示71.37%区域土壤DDTs输入可能与工业级DDTs有关.相关分析表明,影响土壤DDTs分布的外在因素包括土壤Org C、N、C和p H等指标,且DDTs中p,p'-DDT组分占比越高,影响越明显.DDTs的空间分布具明显点源特征,市县周围均出现明显浓集中心,中南部部分区域浓度明显较高.全区DDTs土壤环境质量污染程度较低,主要以一二类土壤为主,分别占78.95%和21.05%.     

高含氮印染废水强化脱氮处理组合工艺

为考察UASB-A/LO/O（缺氧/低氧/好氧）组合工艺的实际应用效果,将该工艺应用到规模为6 000 t/d的实际工程中,考察其对高含氮印染废水处理效果,同时采用微生物高通量测序对A/LO/O工艺中的微生物菌群结构进行解析.结果表明:在前处理废水进水流量为100 m3/h,染色废水进水流量为150 m3/h,同时A/LO/O工艺污泥回流比为50%左右情况下,COD_Cr、NH₃-N和TN的去除率分别达到91.6%、95.5%和73.5%;染色和前处理废水在改良UASB内均实现了高效厌氧氨化,染色废水厌氧出水中ρ（NH₃-N）/ρ（TN）保持在80%以上,前处理废水厌氧出水保持在85%以上;调节UASB运行参数可对VFAs（挥发性脂肪酸）进行有效调控,从而为后段反硝化工艺提供高品质碳源,实现高效脱氮;A/LO/O系统对COD_Cr、NH₃-N、TN有较好的去除效果,其脱氮性能主要靠变性菌门（Proteobateria）发挥作用,该系统中低氧池的微生物种类最为丰富且发生短程硝化反硝化,对污染物去除贡献最大,当低氧池△ρ（COD_Cr）/△ρ（TN）在18.6左右时,TN去除率最高,达到82%.研究显示,该组合工艺对工程中高含氮印染废水的脱氮效果良好.      

Capability of cation exchange technology to remove proven N-nitrosodimethylamine precursors

N-nitrosodimethylamine(NDMA) precursors consist of a positively charged dimethylamine group and a non-polar moiety, which inspired us to develop a targeted cation exchange technology to remove NDMA precursors. In this study, we tested the removal of two representative NDMA precursors, dimethylamine(DMA) and ranitidine(RNTD), by strong acidic cation exchange resin. The results showed that pH greatly affected the exchange efficiency, with high removal(DMA 78% and RNTD 94%) observed at pH pk_a-1 when the molar ratio of exchange capacity to precursor was 4. The exchange order was obtained as follows: Ca~(2+) Mg~(2+) RNTD~+ K~+ DMA~+ NH_4~+ Na~+. The partition coefficient of DMA~+to Na~+was 1.41 ± 0.26, while that of RNTD~+to Na~+was 12.1 ± 1.9. The pseudo second-order equation fitted the cation exchange kinetics well. Bivalent inorganic cations such as Ca~(2+)were found to have a notable effect on NA precursor removal in softening column test. Besides DMA and RNTD, cation exchange process also worked well for removing other 7 model NDMA precursors. Overall, NDMA precursor removal can be an added benefit of making use of cation exchange water softening processes.     

美国市政污水处理排放标准制定对中国的启示

在概述美国市政污水处理排放标准制度体系的基础上,介绍了其制定基于技术的排放限值和基于水质的排放限值的方法,阐述了其制定的科学性,并指出了中国市政污水处理排放标准中存在的相应问题。最后,根据美国制定排放标准限值的经验,对我国污水处理排放标准进行了思考,并提出了科学制定排放标准的方法和建议。     

港口罢工对周边空气质量的影响

港口污染物的排放浓度极大地影响着周边的空气质量,以2013年3月28日香港国际集装箱码头发生的罢工事件为契机来探究港口运作短暂的瘫痪对周边空气质量的影响。首先,进行污染物之间的相关性分析确定影响本次罢工事件的污染物主要为NO_2、NO_x、SO_2以及O_3。其次,基于罢工前、罢工期间以及罢工后污染物排放的浓度变化,进行横向对比发现罢工期间的污染物确实有一定程度的减少。再次,利用纵向对比排除四季带来的影响探究不同年份同一阶段污染物浓度的变化情况评估罢工期间的空气质量。最后,以NO_2为例建立预测模型对罢工期间的NO_2浓度进行预测,根据实际值与预测值之间的差异来说明罢工影响了NO_2的预测趋势。这项研究主要强调港口空气质量对整个环境的影响,在一定程度上说明政府实施政策的有效性,为政府提供了决策支持,同时也要注重污染物之间的相互转化作用对环境的影响。     

Ti/SnO_2-Sb阳极-空气阴极电催化降解染料废水

为解决电化学法处理高盐染料废水存在的能耗大、成本高等问题,分别采用溶胶-凝胶法和辊压法制备Ti/SnO_2-Sb阳极和空气阴极,构建了Ti/SnO_2-Sb阳极-空气阴极双极体系(TSSA-ADC)。甲基橙(MO)作为高盐染料废水的典型污染物,考察了电流强度、MO浓度、电解液浓度和初始p H对TSSA-ADC体系和TSSA单阳极体系降解MO的影响。结果表明:与TSSA单阳极体系相比,TSSA-ADC体系具有更好的抗有机负荷冲击、抗盐分冲击、抗酸碱波动能力,能够维护酸碱平衡防止硬度离子结垢。最佳反应条件为电流强度为0.030 A,电解液浓度为3%,MO浓度为100 mg/L,初始pH=6。以MO去除率达到98%为基准,TSSA-ADC体系比TSSA体系可节能74.26%。     

Effects of free ammonia on volatile fatty acid accumulation and process performance in the anaerobic digestion of two typical bio-wastes

The effect of free ammonia on volatile fatty acid(VFA)accumulation and process instability was studied using a lab-scale anaerobic digester fed by two typical bio-wastes:fruit and vegetable waste(FVW)and food waste(FW)at 35°C with an organic loading rate(OLR)of 3.0 kg VS/(m~3·day). The inhibitory effects of free ammonia on methanogenesis were observed due to the low C/N ratio of each substrate(15.6 and 17.2,respectively). A high concentration of free ammonia inhibited methanogenesis resulting in the accumulation of VFAs and a low methane yield. In the inhibited state,acetate accumulated more quickly than propionate and was the main type of accumulated VFA. The co-accumulation of ammonia and VFAs led to an "inhibited steady state" and the ammonia was the main inhibitory substance that triggered the process perturbation. By statistical significance test and VFA fluctuation ratio analysis,the free ammonia inhibition threshold was identified as 45 mg/L. Moreover,propionate,iso-butyrate and valerate were determined to be the three most sensitive VFA parameters that were subject to ammonia inhibition.     

Quantifying public health benefits of environmental strategy of PM2.5 air quality management in Beijing–Tianjin–Hebei region, China

In 2013,China issued "Air Pollution Prevention and Control Action Plan(Action Plan)" to improve air quality.To assess the benefits of this program in Beijing-Tianjin-Hebei(BTH)region,where the density of population and emissions vary greatly,we simulated the air quality benefit based on Ben MAP to satisfy the Action Plan.In this study,we estimate PM_(2.5) concentration using Voronoi spatial interpolation method on a grid with a spatial resolution of 1 × 1 km~2.Combined with the exposure-response function between PM_(2.5) concentration and health endpoints,health effects of PM_(2.5) exposure are analyzed.The economic loss is assessed by using the willingness to pay(WTP) method and human capital(HC) method.When the PM_(2.5) concentration falls by 25% in BTH and reached 60 μg/m~3 in Beijing,the avoiding deaths will be in the range of 3175 to 14051 based on different functions each year.Of the estimated mortality attributable to all causes,3117 annual deaths were due to lung cancer,1924 – 6318 annual deaths were due to cardiovascular,and343 – 1697 annual deaths were due to respiratory.Based on WTP,the estimated monetary values for the avoided cases of all cause mortality,cardiovascular mortality,respiratory mortality and lung cancer ranged from 1110 to 29632,673 to 13325,120 to 3579,1091 to 6574 million yuan,respectively.Based on HC,the corresponding values for the avoided cases of these four mortalities were 267 to 1178,161 to 529,29 to 143 and 261 million yuan,respectively.