Cause of PM2.5 pollution during the 2016-2017 heating season in Beijing, Tianjin, and Langfang, China

To investigate the cause of fine particulate matter (particles with an aerodynamic diameter less than 2.5 µm, PM_2.5) pollution in the heating season in the North China Plain (specifically Beijing, Tianjin, and Langfang), water-soluble ions and carbonaceous components in PM_2.5 were simultaneously measured by online instruments with 1-hr resolution, from November 15, 2016 to March 15, 2017. The results showed extreme severity of PM_2.5 pollution on a regional scale. Secondary inorganic ions (SNA, i.e., NO₃^?+SO₄²+ NH₄⁺) dominated the water-soluble ions, accounting for 30%-40% of PM_2.5, while the total carbon (TC, i.e., OC + EC) contributed to 26.5%-30.1% of PM_2.5 in the three cities. SNA were mainly responsible for the increasing PM_2.5 pollution compared with organic matter (OM). NO₃^? was the most abundant species among water-soluble ions, but SO₄^2- played a much more important role in driving the elevated PM_2.5 concentrations. The relative humidity (RH) and its precursor SO₂ were the key factors affecting the formation of sulfate. Homogeneous reactions dominated the formation of nitrate which was mainly limited by HNO₃ in ammonia-rich conditions. Secondary formation and regional transport from the heavily polluted region promoted the growth of PM_2.5 concentrations in the formation stage of PM_2.5 pollution in Beijing and Langfang. Regional transport or local emissions, along with secondary formation, made great contributions to the PM_2.5 pollution in the evolution stage of PM_2.5 pollution in Beijing and Langfang. The favourable meteorological conditions and regional transport from a relatively clean region both favored the diffusion of pollutants in all three cities.     

含盐废水SBR工艺的快速启动与运行

为了实现含盐废水SBR工艺的快速启动,研究采用逐步提高盐度负荷的方法对活性污泥进行驯化。结果表明,盐的质量浓度分别为2.5、5.0、7.5和10 g/L时,经过280 d的驯化,活性污泥可以有效地降解含盐废水,COD去除率均高于82.92%,氨氮去除率高于90%,形成了以耐盐细菌为优势菌种的微生物群体,实现了SBR工艺处理含盐废水的快速启动。     

Retention of 137cesium in acid sulphate soils of South Central Thailand

Adsorption and desorption of ¹³⁷Cs by acid sulphate soils from the Nakhon Nayok province, South Central Plain of Thailand located near the Ongkarak Nuclear Research Center (ONRC) were investigated using a batch equilibration technique. The influence of added limestone (12 and 18 tons ha^?1) on ¹³⁷Cs adsorption–desorption was studied. Based on Freundlich isotherms, both adsorption and desorption of ¹³⁷Cs were nonlinear. A large portion (98.26–99.97%) of added ¹³⁷Cs (3.7?×?10³?7.03?×?10⁵ Bq l^?1) was sorbed by the soils with or without added lime. The higher lime treatments, however, favoured stronger adsorption of ¹³⁷Cs as compared with soil with no lime, which was supported by higher K _ads values. The addition of lime, the cation exchange capacity and pH of the soil increased and hence favoured the stronger adsorption of ¹³⁷Cs. Acid sulphate soils with a high clay content, medium to high organic matter, high CEC, and predominant clay types consisting of a mixture of illite, kaolinite, and montmorillonite were the main soil factors contributing to the high ¹³⁷Cs adsorption capacity. Competing cations such as NH₄ ⁺, K⁺, Na⁺, Ca²⁺, and Mg²⁺ had little influence on ¹³⁷Cs adsorption as compared with liming, where a significant positive correlation between K _ads and soil pH was observed. The ¹³⁷Cs adsorption–desorption characteristics of the acid sulphate soils studied exhibited a very strong irreversible sorption pattern. Only a small portion (0.09–0.58%) of ¹³⁷Cs adsorbed at the highest added initial ¹³⁷Cs concentration was desorbed by four successive soil extractions. Results clearly demonstrated that Nakhon Nayok province acid sulphate soils have a high ¹³⁷Cs adsorption capacity, which limits the ¹³⁷Cs bioavailability.     

Predicting the degradation pattern of organic materials in the composting of a fed-batch operation as inferred from the results of a batch operation

The degradation pattern of organic materials was confirmed by continuously measuring the quantity of CO₂ evolved during the composting process in both batch and fed-batch operations. It was possible to predict the degradation pattern for organic material during a fed-batch operation from that observed during a batch operation after corrections made on the basis of two suppositions. First, it was assumed that the degradation of dog food (which degrades easily) occurred prior to the degradation of the bulking agent and seeding material that were contained in the raw compost mixture; second, it was assumed that the dog food thrown into the fed-batch operation, where the microorganisms were already proliferating, began to be actively degraded with only a short lag time. Received: June 16, 1998 / Accepted: August 7, 1999     

Adsorption of nutrients and cadmium by different minerals: experimental studies and modelling

This work analyses cadmium sorption by natural vermiculite, zeolite, and pumice, which have been recently considered for their potential use in remediation of contaminated soils. Batch experiments were performed to investigate the interactions between the mineral surfaces and the main nutritive cations of Hoagland solution. In addition to their ameliorative effect of reducing metal mobility, these minerals are able to interact to different extents with various components of the nutrient solution and can change the availability of essential nutrients in solution. Therefore, the minerals were also exposed to a range of cadmium doses to compare their different affinities for this element and to analyse the cadmium–nutrient interactions. The results showed that the nutrient solution composition was significantly modified by contact with zeolite and vermiculite, and to a minor extent with pumice. The ionic equilibrium between the solid and aqueous phases was attained at several time points depending on the cation. Ammonium and potassium ions were almost entirely absorbed by zeolite, while in vermiculite endogenous magnesium ions were exchanged with the liquid phase calcium ions. The amount of cadmium adsorbed on mineral surfaces equilibrated with the nutrient solution showed the following sequence zeolite>vermiculite>pumice, and the cation concentrations of the fluid phase were sensitive to cadmium addition.     

有机碳源对同时硝化/反硝化(SND)过程的影响

究了同时硝化 反硝化 (SimultaneousNitrificationandDenitrification ,SND)体系中有机碳源对氨氮去除的影响。实验结果表明 ,在氨氮初始浓度为 35mg L时 ,存在使氨氮降解率达到 99 5 %以上的有机碳源浓度区间 ,其CODCr浓度为40 0mg L～ 10 0 0mg L ;为保证反应后期体系中C N维持在微生物所需的水平 ,提出了补料的方式 ,使得氨氮降解不会出现停滞阶段 ,可以达到较好的去除效果 ;在周期为 8h的连续序批式 (SBR)操作中 ,采用较高的有机碳源初始进料值 ,并在反应过程中进行补料 ,可以很好的将出水氨氮的浓度维持在较低值 (<5mg L)     

Adsorption/Desorption of Copper by a Sandy Soil Amended with Various Rates of Manure,Sewage Sludge,and Incinerated Sewage Sludge

Organic amendments are sometimes applied to agricultural soils to improve the physical, chemical, and microbiological properties of the soils. The organic fractions in these soil amendments also influence metal reaction, particularly the adsorption and desorption of metals, which, in turn, determine the bioavailability of the metals and hence their phytotoxicities. In this study, a Quincy fine sandy (mixed, mesic, Xeric Torripsamments) soil was treated with 0 to 160 g kg^?1 rates of either manure, sewage sludge (SS), or incinerated sewage sludge (ISS) and equilibrated in a greenhouse at near field capacity moisture content for 100 days. Following the incubation period, the soil was dried and adsorption of copper (Cu) was evaluated in a batch equilibration study at either 0, 100, 200, or 400 mg L^?1 Cu concentrations in a 0.01M CaCl₂ solution. The desorption of adsorbed Cu was evaluated by three successive elutions in 0.01M CaCl₂. Copper adsorption increased with an increase in manure rates. At the highest rate of manure addition (160 g kg^?1 soil), Cu adsorption was two-fold greater than that by the unamended soil at all rates of Cu additions. With increasing rates of Cu additions, the adsorption of Cu decreased from 99.4 to 77.6% of Cu applied to the 160 g kg^?1 manure amended soil. The desorption of Cu decreased with an increase in rate of manure amendment. Effects of sewage sludge amendments on Cu adsorption were somewhat similar to those as described for manure additions. Likewise, the desorption of Cu was the least at the high rate of SS addition (160 g kg^?1), although at the lower rates there was not a clear indication of the rate effects. In contrast to the above two amendments, the ISS amendment had the least effect on Cu adsorption. At the highest rate of ISS amendment, the Cu adsorption was roughly 50% of that at the similar rate of either manure or SS amendments, across all Cu rates.     

葫芦岛龙湾新区污水厂工艺比选

本文介绍了葫芦岛市龙湾新区污水厂厂址及生物处理工艺等的选择。通过技术经济比较,选择建二处污水厂分别处理新、老城区的污水,并建两座小型地埋式污水处理站,选择SBR工艺作为新区污水处理厂二级生物处理工艺。     

固体吸附热脱附气相色谱质谱法测定半导体行业废气中的VOC_S

采用固体吸附热脱附气相色谱质谱法对半导体行业废气中的VOCs进行了测定,每个分析物质的方法捡出限0.02mg/m3,回收率73%～123%,线性范围宽.