Clean technology in the production of epichlorohydrin

The conventional production of epichlorohydrin takes place via allyl chloride and dichlorohydrin. A major disadvantage of this chemical process is the formation of a large amount of chlorinated organic by-products, which are found partially in the voluminous effluent. In order to reduce this emission to surface water, measures have to be taken. Technical measures varying from end-of-pipe techniques to alternative processes have been evaluated. Application of end-of-pipe techniques is not the optimal solution for emission reduction, either technically or economically. Results from in-process measures focused on reduction of the amount of waste water and contaminants are more promising. However, the development of an alternative route is necessary in order to obtain a process with minimal emissions and minimal costs.     

Occurrence and fate of pharmaceuticals and personal care products (PPCPs) in biosolids

Each year, large quantities of pharmaceuticals and personal care products (PPCPs) are used worldwide. Once conveyed to wastewater treatment plants, PPCPs can remain unchanged or undergo partial or complete transformation during wastewater treatment processes before discharge into the environment via effluent and biosolids for land application. Biosolids can be a major sink for some PPCPs. Previous investigations have indicated that land application of biosolids may be a potential important route through which PPCPs enter the environment. However, no information is available on exactly how closely the concentrations of PPCPs in the environmental media are related to the land application of PPCP-containing biosolids. This paper reviews currently available information on the occurrence of PPCPs in biosolids, methods of analysis, the potential fate of PPCPs in biosolids-applied soils, and composting as a potential means for removal of PPCPs from biosolids.     

Influence of sublethal ammonia toxicity on some physiological parameters of Labeo rohita (Hamilton-Buchanan) fingerlings

Fingerlings of Labeo rohita subjected to sublethal unionized ammonia (0.132mg/l) for 30 days exhibited significant changes. Increase in haemoglobin, haematocrit, plasma cortisol, plasma glucose, plasma cholesterol and plasma lactic acid levels whereas, decrease in plasma chloride, liver and muscle glycogen, hepatosomatic index and DNA/RNA ratio of muscles with stable plasma protein was observed. Metabolic recovery was not observed within 30 days of exposure.     

Water-induced erosion potentiality and vulnerability assessment in Kangsabati river basin,eastern India

Environment, Development and Sustainability - The large-scale water-induced erosion is one of the most determining elements on land degradation in subtropical monsoon-dominated region. From this...     

遥感与地理信息系统对资源利用热点地区的初步应用——-以印度北部山地小流域为例

资源利用与资源退化在时间及空间领域上的表现有所分异。识别出那些受人为干扰严重且易于发生资源退化的区域(资源利用的热点地区),对这些区域给予重视并采取特殊的管理机制以避免资源的进一步退化和环境的恶化,对资源的可持续利用具有重要的现实意义。论文以印度北部山地小流域的研究为例,根据当地实际情况,选取4个参数作为评价指标,即资源利用的重要性、资源的需求程度、资源利用的可获取性以及人类活动造成的景观生态学的干扰指数,利用遥感技术和地理信息系统对资源利用热点地区的识别进行了初步探讨。通过研究,将该流域划分为3种区域,即高度敏感区、中度敏感区和低敏感区,分别体现了不同的资源退化在空间上的分布。     

Synthesis of SnO2 quantum dots mediated by Camellia sinensis shoots for degradation of thiamethoxam

Abstract

A novel method of synthesis of tin dioxide quantum dots employing Camellia sinensis shoots as reducing agent and stabilizer is presented. The quantum dots were characterized by UV spectroscopy, X-Ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The crystalline tin dioxide quantum dots with an average size of 4.3?nm were of flake like morphology capped by phenolic compounds of Camellia sinensis. The quantum dots were employed for the photocatalytic degradation of thiamethoxam resulting in 57% degradation within 45 mins.     

Investigation of some basic water quality parameters of the north Bengal Terai river Kaljani--a tributary of river Torsa, and comparison thereof with the mainstream

Some physico-chemical parameters of Kaljani River were studied in and around Alipurduar municipality. The principal characteristics of Kaljani River are high TSS, Mg-hardness, COD, and Phosphate 'P' Comparison of water quality parameters of the two rivers demonstrated higher range of alkalinity, ammonia 'N' content and chloride content in Torsa than Kaljani. River Kaljani showed higher COD range than Torsa. Mean BOD value of both these rivers ranged between 0.93-1.65 mg/l. Overall TDS content of Kaljani was found to be lower than Torsa. Maximum phosphate 'P' content was observed at the downstream of both the rivers.     

A design of a vermiculite column adsorber for the removal of lead from water

Mini-column techniques were employed to determine the mass transfer coefficient for lead adsorption onto vermiculite. Variation of the mass transfer coefficient with flow rate, particle size of sorbent, and influent lead concentration were studied. Multiple linear regression (MLR) analysis showed that the mass transfer coefficient varied as the 0.43 power of the liquid flow rate and inversely as the 0.272 power of particle diameter of the vermiculite, but was independent of the influent concentration of lead. Different parameters of a fixed bed column design for the removal of lead by vermiculite were determined using the data from the batch sorption study. The performance of the liquid bed column in removing lead was in close agreement with predicted performance using the batch isotherm data.