Modeling assessment for ammonium nitrogen recovery from wastewater by chemical precipitation

Chemical precipitation to form magnesium ammonium phosphate (MAP) is an effective technology for recovering ammonium nitrogen (NH4 +-N). In the present research, we investigated the thermodynamic modeling of the PHREEQC program for NH4 +-N recovery to evaluate the effect of reaction factors on MAP precipitation. The case study of NH4 +-N recovery from coking wastewater was conducted to provide a comparison. Response surface methodology (RSM) was applied to assist in understanding the relative significance of reaction factors and the interactive effects of solution conditions. Thermodynamic modeling indicated that the saturation index (SI) of MAP followed a polynomial function of pH. The SI of MAP increased logarithmically with the Mg2+/NH4 + molar ratio (Mg/N) and the initial NH4 +-N concentration (CN), respectively, while it decreased with an increase in Ca2+/NH4 + and CO3 2??/NH4 + molar ratios (Ca/N and CO3 2??/N), respectively. The trends for NH4 +-N removal at different pH and Mg/N levels were similar to the thermodynamic modeling predictions. The RSM analysis indicated that the factors including pH, Mg/N, CN, Ca/N, (Mg/N) (CO3 2??/N), (pH)2, (Mg/N)2, and (CN)2 were significant. Response surface plots were useful for understanding the interaction effects on NH4 +-N recovery.     

东胜区三台基水库水质细菌的鉴定

为了初步探索环境微生物的快速测定法,提升应对微生物污染突发事件的能力,本文运用美国BD公司的细菌鉴定系统对东胜区三台基水库水质细菌进行了鉴定。结果共鉴定出6种细菌,其可信度分别为95.7、99．1、94．3、98．7、98．5、和99．2。结果表明该系统快速、准确、可靠,可以作为环境微生物分类鉴定和微生物污染突发事件应急监测的依据。     

Molecular characterization and developmental expression patterns of thyroid hormone receptors (TRs) and their responsiveness to TR agonist and antagonist in Rana nigromaculata

Considering some advantages of Rana nigromaculata as an experimental species, we propose that this species, like Xenopus laevis, could be used to assay thyroid hormone（TH） signaling disrupting actions. To validate the utilizability of R. nigromaculata, we investigated the responsiveness of R. nigromaculata to a TH receptor（TR） agonist（T3） and antagonist（amiodarone） by analyzing expression, based on characterizing TR cDNA and developmental expression patterns. With high levels of identity with the corresponding genes in X. laevis, both TRα and TRβ in R. nigromaculata exhibited roughly similar developmental expression patterns to those of X. laevis, in spite of some species-specific differences. Both TRα and TRβ expression had greater changes in the liver and intestine than in the tail and brain during metamorphosis. T3 exposure for 2 days induced more dramatic increases of TRβ expression in stage 27 than in stage34 tadpoles but not in stage 42 tadpoles, showing that the responsiveness of R. nigromaculata to TH decreased with development and disappeared at the onset of metamorphic climax.Corresponding to greater changes of TRβ expression in the liver and intestine than in the tail and brain during metamorphosis, the liver and intestine had higher responsiveness to exogenous T3 than the tail and brain. Amiodarone inhibited T3-induced TRβ expression. Our results show that R. nigromaculata can be used as a model species for assaying TH signaling disrupting actions by analyzing TRβ expression, and intestine tissues at stage 27 are ideal test materials due to high responsiveness and easy accessibility.     

清河流域水环境质量监测与评价研究

近年来,随着全球各地城市化和工业化进程的不断加快,以及人类对河流水生态系统资源的不合理、掠夺式利用,河流水生态系统遭到严重破坏,各地河流相继出现水质恶化、水文条件改变、物种多样性退化、生境条件恶劣等诸多问题。文章对辽河主要支流清河水生态系统的水质状况进行了研究,并于2012年6月,对清河流域22个监测断面水质状况进行了实地调查,对其水质状况进行了评价,结果表明:22个监测断面中,达到Ⅲ类水质断面的有8个,Ⅳ类7个,Ⅴ类1个,劣Ⅴ类6个。其中6个劣Ⅴ类断面分别因氟化物、氨氮、总磷浓度超标而为劣Ⅴ类。     

基于综合水质标识指数法的四川西充河水质评价

四川省西充河为严重污染河流,选取溶解氧(DO)、氨氮(NH+4-N)、五日生化需氧量(BOD5)、总氮(TN)、总磷(TP)5项指标年平均值,采用综合水质标识指数法,研究了西充河近10年水质状况随时间变化趋势及水污染特征。2003年至2010年水质级别为劣V类,2011年和2012年水质级别为Ⅳ类,水质标识指数Iwq从2003年的12.459逐渐降低到2012年的4.431。西充河近10年水质状况整体呈好转趋势,但未达到国家规定的Ⅲ级水质标准,水质标识指数Iwq结果表明该好转的速度较慢,西充河水质状况有较大的上升潜力和空间。总氮(TN)和氨氮(NH+4-N)为河流主要污染物,为了达到国家Ⅲ级水质标准,西充河的治理已刻不容缓。     

A phenomenological approach shows a high coherence of warming patterns in dimictic aquatic systems across latitude

To predict the coherence in local responses to large-scale climatic forcing among aquatic systems, we developed a generalized approach to compare long-term data of dimictic water bodies based on phenomenologically defined hydrographic events. These climate-sensitive phases (inverse stratification, spring overturn, early thermal stratification, summer stagnation) were classified in a dual code (cold/warm) based on threshold temperatures. Accounting for a latitudinal gradient in seasonal timing of phases derived from gradients in cumulative irradiation (2.2?days per degree latitude), we found a high spatial and temporal coherence in warm–cold patterns for six lakes (84?%) and the Baltic Sea (78?%), even when using the same thresholds for all sites. Similarity to CW-codes for the North Sea still was up to 72?%. The approach allows prediction of phase-specific warming trends and resulting instantaneous or time-delayed ecological responses. Exemplarily, we show that warming during early thermal stratification controls food-web-mediated effects on key species during summer.     

高压喷射技术加固地基的工程实践

概述了在辽宁大洼县田庄台抽水站地基处理工程中采用高压喷射注浆技术的实践经验，并介绍了从工程勘察、方案选择、设计、施工和检测的全过程。此项技术，经过长期沉降观测取得了良好的加固成果。     

镇江市综合防灾系统中消防信息的输入与管理

本文以镇江市消防地图及其相关信息为对象,分析了消防信息的特点和现有的输入方法,以及作者在设计与建造镇江市消防信息数据库的实践中采用的技术路线和具体方法。     

静电除尘在烧结机头烟尘治理中的应用

通过对安钢烧结机一、二期工程中烧结机头电除尘器结构性能和运行效果对比，结合安钢实际运行情况，分析了一期工程中电除尘器的运行存在的问题，重点对电除尘器的结构特点进行阐述，以提供一种适用于烧结机头烟尘治理的电除尘技术。     

南水北调中线工程对汉江中下游工业发展的影响

南水北调中线工程计划从丹江口水库向我国北方每年调水１４５亿ｍ＾３,汉江丹江口以下地区的水资源量将随之相应减少。汉江中下游地区是湖北省盐化工、机械、石油、食品、化肥、电力的重要生产地区,是湖北省的汽车工业走廊,其经济在湖北省占有举足轻重的地位。由于经济的迅速发展,下世纪工农业生产和人民生活对水资源的需求将从现在的１４０亿ｍ＾３增加到２５０亿ｍ＾３以上,需水量将达到水资源量的５８％,潜伏着严重的水资源