固体废物焚烧二恶英的生成机制及其控制技术

结合国内外近年来的研究成果,重点介绍了固体废物焚烧过程中二恶英的生成机制及其控制技术,在此基础上,针对我国国情,提出了二恶英的污染控制对策。     

水中苦味酸的测定

将水样中的苦味酸氯化后,用ECD气相色谱法测定氯化苦的量,来确定苦味酸的浓度。采用保留时问定性,外标法定量。实验表明,该方法能快速有效地提取并测定水体中的苦味酸。在HP-5毛细管柱上,对苦味酸的氯化产物有较好的分离效果。方法快速、反应较为彻底,灵敏度高、精密度和准确度较好。     

城市生活垃圾的生物工程堆肥化利用

在建立节约型社会、发展循环经济时代,通过对城市生活垃圾3种处理方法的比较得出,以堆肥方式通过生物工程技术对城市生活垃圾进行科学合理处置,是达到城市生活垃圾无害化、资源化、减量化、规模化处理的最佳选择。     

稀土对低浓度硫化氢液相催化氧化净化效率的影响

采用液相催化氧化法净化低浓度H2S,系统研究了反应温度、pH值及助催化剂--稀土(La、Ce)的加入量对吸收液净化效率和硫容量的影响.结果显示,在优化的实验条件下(原料气H2S浓度720～920mg·m-3、反应温度60℃、pH=9.0、Fe3+浓度0.05mol·L-1、吸收液体积50mL)添加表面恬性剂磺基水杨酸和稀土助催化剂后.吸收液具有较高的净化效率(98%以上)和较大的硫容量(4g·L-1以上).     

污泥土地利用中重金属铜在土壤中的迁移行为

研究通过模拟土柱淋溶实验来研究污泥土地利用中重金属铜在土壤中的迁移行为。结果表明污泥土地利用会明显增加土壤中铜的总量,但大部分集中在40 cm以上的土壤中。通过BCR连续提取法发现,经淋溶后耕作层（0 cm~30 cm）土壤中的铜仍然以残渣态为主（占50%以上）,但能被植物利用的酸溶/可交换态和可还原态铜有了明显的增加。与去离子水相比,模拟酸雨（pH=4.5）会使土壤中铜的淋溶强度增加,并更能促使其向下迁移。     

Effects of 5-year application of municipal solid waste compost on the distribution and mobility of heavy metals in a Tunisian calcareous soil

It is obvious that the application of solid waste compost improves the soil fertility. These wastes, however, may also have some negative effects on the agricultural environment due to their metal content. This research aimed at evaluating the influence of Tunisian municipal solid waste compost and farmyard manure on some chemical properties and the distribution of heavy metals in a calcareous Tunisian soil (clayey–loamy soil). A field plot experiment, without vegetation, was installed since 1999 at the experimental farm of the Agronomic National Institute of Tunis (INAT) in the region of Mornag (20 km south of Tunis, Tunisia). During 5 years, the field received yearly the following treatments: 0, 40, 80 and 120 t/ha of municipal solid waste compost and 0, 40 and 120 t/ha of manure. The fractionation of heavy metals in the soil was evaluated after 5 years using a sequential extraction procedure. The application of the two amendments was found to increase the content of organic matter, the total nitrogen content and the electrical conductivity, whereas it slightly decreased the soil pH. The addition of manure did not have a significant effect on the accumulation of heavy metals in the soil, whereas compost application increased the total concentration of heavy metals in the soil. The distribution of heavy metals between the different fractions in untreated and treated soils showed the residual fraction to be dominant, followed by the fraction bound to Fe and Mn oxides. The amount of Cu bound to the organic fraction increased with the application rate, which is probably caused by the formation of organic complexes. For the other metals, the increase of the association with organic matter is very limited. The application of compost moreover increases the amount of Zn associated with Fe and Mn oxides. The “Mobility Factor (MF)” was quite low and did not change after the 5-year application of the two organic amendments. It always remained lower than 10%, although for Cd it amounted to 17%.     

Concentrations and chemical forms of potentially toxic metals in road-deposited sediments from di erent zones of Hangzhou, China

The 25 road-deposited sediments were collected from five di erent land-use zones (industrial, residential, commercial, park, and countryside) in Hangzhou, China. The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in these samples were determined using ICP-AES after digestion with the mixture of HNO3-HF-HCl (aqua regia), and chemically fractionated according to the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. The high metal concentration levels were detected in the sample from industrial zone and commercial zone having heavy tra c. While the low metal levels were noted in the street dust sample from residential zone, park, and countryside zone. The mobility sequence based on the sum of the BCR sequential extraction stages was: Zn (80.28%), Pb (78.68%), Cd (77.66%) > Cu (73.34%) > Mn (67.92%) > Co (41.66%) > Ni (30.36%) > Cr (21.56%), Fe (20.86%). Correlation analysis and principal component analysis were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. Factor analysis showed that these areas were mainly contaminated by three sources, namely lithology, tra c, and industry.     

饥饿期间增加曝气量好氧颗粒污泥的形成特点

高有机负荷率8.0kgCOD(/m3·d)条件下,通过两种不同的曝气方式研究好氧颗粒污泥的形成特点,即在反应器R1中采用恒定的曝气流量,而在反应器R2中,30min曝气后,进行沉淀和排水,然后采用较大的曝气流量进行曝气。研究发现:(1)外部基质在前30min被快速降解,其溶解性有机碳DOC基本被消耗到最低水平;(2)在中途排水后的饥饿状态下增加曝气量的反应器R2相对于曝气量一直不变且中途未排水的R1而言,颗粒变的大而疏松,即:在R2中颗粒尺寸>0.9mm占有93%,而颗粒密度均<1.016g/mL。(3)反应器R2在饥饿状态下增加曝气量可以使胞外多聚物(EPS)糖类被当作基质被消耗。     

粒度对煤矸石活化效率的影响

煤矸石煅烧活化是煤矸石为原料提取铝、硅等化工原料的重要环节,煤矸石破碎粒度对煅烧活化效率有重要影响。文章以山西潞安的煤矸石为原料,利用煅烧活化-酸溶法提取煤矸石中的铝,研究了粒度对煤矸石活化效率的影响。实验确定铝溶出的较优工艺条件为:煅烧温度650℃、20%盐酸225mL/100g煤矸石、固液比1:3、酸浸时间3h,在此工艺条件下研究矸石粒度对铝和铁溶出的影响。结果表明:物料粒度对活化效果影响显著,当物料粒度为60～80目时,铝的溶出率最大达到79%;物料与空气充分接触有利于提高活化效果,动态煅烧活化效率显著高于静态煅烧,粒度对煅烧效果产生的重要影响很大程度来源于空气接触比表面积。     

API standard 521 guidance on mixing of hot/cold liquids and prevention of superheat limit explosions

American Petroleum Institute (API) standards and recommended practices have identified inadvertent mixing of hot and cold liquids as a potential cause for equipment overpressure since 1955. The limited guidance has been informative but provides minimal if any details on conditions that could cause an overpressure and its potential severity. Therefore, the user must interpret how and when to prevent and/or mitigate the scenario. This guidance has changed little over the years. In June 2020, API published the 7th Edition of API Standard 521 which now provides specific guidance as to conditions whereby pressure relief devices can be considered for protection and conditions where prevention remains as the only recourse. This paper discusses the basis for the revised guidance in API Standard 521 and includes supplemental guidance.