Significance of iron compounds in chemical and electro‐oxidation treatment of sugar industry wastewater: Batch reaction

Industrialization plays a major role in a nation's growth. However, with an increase in industrial activities, pollution levels are also increasing. Among all industries, the sugar‐processing industry is one that requires large amounts of water to process the sugar, and, consequently, it discharges large amounts of water as effluent. Highly polluted wastewater brings changes to the physicochemical characteristics of the surrounding environment. Iron compounds have had a significant impact when they are used in wastewater treatment in various applications, including when they are used to minimize the pollution levels in sugar industry wastewater (SIWW). To minimize the pollutant levels from SIWW, iron compounds have been key for uses in treatments involving chemical and electro‐oxidation. Two different methodologies of electrocoagulation and chemical coagulation have been used to treat SIWW. In electrocoagulation, an iron plate is used as an electrode material under specific operating conditions. Ferrous sulfate and ferric chloride have been used as chemical coagulants at various pH and mass loading levels. The use of iron metals shows an 82% reduction in chemical oxygen demand (COD) and an 84% reduction in color at the optimum condition of pH 6, an electrode distance of 20 millimeters, and a current density of 156 square centimeters. As a chemical coagulant, iron salt (ferrous sulfate) provides a reduction of 77% COD and a 91% reduction of color at pH 6 and a 40‐millimole mass loading. Electrochemical treatment using iron was found to be suitable to treat SIWW. The sludge generated after treatment can be burned or composted with the possible recovery of some of the treatment costs.     

不同载体对淀粉酶固定化的比较研究

采用海藻酸钠微胶囊法和壳聚糖交联法对淀粉酶进行固定化,比较两种淀粉酶固定化方法的优劣。结果表明,两种固定化酶的活力回收分别为33．2％、26．6％,比活力分别为27．1U／mg蛋白、24．2U／mg蛋白,最适pH分别为5．0、8．0。海藻酸钠微胶囊法热稳定性、pH稳定性、操作稳定性、贮存稳定性明显高于壳聚糖交联法,因此海藻酸钠微胶囊法较佳,具有一定应用价值。     

嗜盐菌在油田含盐采出废水处理中的应用

嗜盐菌具有独特的细胞结构、生理功能和代谢产物,能够在高盐环境下正常生存和生长,适宜于偏碱性的环境,因而能有效应用于含盐污染物的治理。结合油田含盐采出废水的特点,介绍了嗜盐菌的特点、嗜盐机制等,及嗜盐菌在含盐采出废水和其它有机污染物处理中的作用,为油田含盐采出废水的处理提供理论基础和技术依据,并为更大范围地推广嗜盐菌在油田含盐采出废水处理中的应用提供技术参考。     

上覆水营养盐浓度对底泥氮磷释放的影响

采用校园水体底泥进行上覆水营养盐浓度对底泥释放量之间的关系研究。结果表明,在本实验条件下,上覆水水质影响底泥氮、磷的释放,尤其显著影响氮、磷的初期释放;上覆水氮、磷的浓度越小,底泥氮、磷的释放量越大;上覆水氮、磷的浓度超过一定值,会抑制底泥氮、磷的释放。     

顶空气相色谱法测定食品中甜蜜素含量

采用顶空气相色谱法测定食品中甜蜜素含量,探讨了气液相平衡条件及色谱条件的选择,实验结果表明甜蜜素的标准溶液在0.1-0.4μg/l范围内具有良好的线性关系,回收率为87.5%-101.8%,相对标准偏差为2.6%.     

Evaluation of tidal marsh restoration: Comparison of selected macroinvertebrate populations on a restored impounded valley marsh and an unimpounded valley marsh within the same salt marsh system in Connecticut,USA

Macroinvertebrates were examined on an impounded valley marsh in Stonington, Connecticut, that has changed from aTypha-dominated system to one with typical salt-marsh vegetation during 13 years following the reintroduction of tidal exchange. Animal populations on this restored impounded marsh were evaluated by comparing them with populations on a nearby unimpounded valley marsh of roughly the same size. Populations of the high marsh snail,Melampus bidentatus Say, were quantitatively sampled along transects that extended from the water-marsh edge to the upland; those of the ribbed mussel,Geukensia demissa Dillwyn, were sampled in low marsh areas on transects along the banks of creeks and mosquito ditches. The occurrence of other marsh invertebrates also was documented, but their abundance was not measured. The mean density ofMelampus was 332±39.6 SE/m² on the restored impounded marsh and 712±56.0 SE/m² on the unimpounded marsh. However, since snails were larger on the restored impounded marsh, the difference in snail biomass was less pronounced than the difference in snail density. MeanMelampus biomass was 4.96±0.52 SE g dry wt/m² on the restored impounded marsh and 6.96±0.52 SE g dry wt/m² on the unimpounded marsh. On the two marshes, snail density and biomass varied in relation to plant cover and other factors. The density and biomass ofGeukensia at the edge of the marsh were comparable on the restored impounded and unimpounded marshes. Mean mussel densities ranged from 80 to 240/m² and mean mussel biomass varied from 24.8–64.8 g dry wt/m² in different low marsh areas. In contrast, below the impoundment dike, meanGeukensia density was 1100±96.4 SE/m² and meanGeukensia biomass was 303.6±33.28 SE g dry wt/m². A consideration of all available evidence leads to the conclusion that the impounded marsh is in an advanced phase of restoration.     

废液处理新工艺超临界水氧化（SCWO）评述

超临界水氧化是一项对有机废液焚烧处理最有潜力的替代技术,在过去的20多年里,这项技术引起了广泛的关注。然而,作为一项管端技术,超临界水氧化仍存在许多不足,这些不足阻碍了它的工业应用。除了反应器腐蚀和盐析导致的技术问题外,超临界水氧化经常被认为是一项处理所有废液的“通用”技术,然而也是无法实现的“通用”技术。本文介绍了作为管端处理技术的超临界水氧化技术存在的问题,讨论了可能的解决办法,介绍了不同反应器的概念,提出了在超临界水氧化领域里开展进一步研究和发展新工艺流程的建议。此外,评价了超临界水氧化技术涉及到的自身能源供应问题。     

Photodegradation of sulfonamide antibiotics in simulated and natural sunlight: Implications for their environmental fate

The photochemical fate of seven sulfonamides was investigated in matrices representative of natural water bodies under various light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield (QY) and first-order rate constants were determined. The photolysis decay rate was dependent on the protonation state of the molecule, pH of the water sample and dissolved organic matter. Natural organic matter was the most significant factor in the indirect photolysis of sulfonamides. Half-lives were in the range of minutes at 254 nm to days under natural sunlight. Under natural sunlight, all sulfonamides showed higher removal rates in natural waters implying that indirect photolysis is the predominant mechanism.     

MODEL STUDIES OF SALT WATER INTRUSION1

Model studies were and are still being used to verify certain theories in ground-water flow systems in general. In complex cases, the model studies may be extremely useful especially when a theoretical rigorous analysis does not exist. The models cannot be considered entirely satisfactory due to the several drawbacks in each type in addition to the normal human errors in experimentation. This paper is concerned only with the viscous flow models. However, a brief summary of the other types of models, which may possibly be used in connection with salt water intrusion problems is given. It should be noted that some of such experiments are not directly related to the field of salt water intrusion. Two main types lie within this category: The gravity flow systems which are analogous to some phases of salt intrusion problems and problems in oil fields which bear general similarities to sea water intrusion zones. In oil fields, gas cycling studies give valuable information to sea water problems. Model studies are used by hydraulic engineers, geologists, petroleum engineers, physicists, foundation engineers and several other professional groups.     

磷肥厂副产氟硅酸利用的新方法

以磷肥厂副产氟硅酸为原料 ,加上碳酸钠 ,在适宜的工艺条件下反应 ,制取符合GB42 93— 84一级品的氟化钠和符合GB10 5 71— 89的白炭黑。该工艺具有原料易得、能耗低、成本低、投资省、无污染、经济效益好等优点