管式法高压聚乙烯装置的道化学火灾爆炸危险指数评价

运用道化学火灾爆炸危险指数评价方法,对Quantum管式法高压聚乙烯装置中多次出现泄漏火灾的聚合单元进行评价。对照装置实际分析了防火防爆缺陷因子,提出完善聚合单元的防火防爆措施。     

以聚己内酯作为生物反硝化固体碳源的研究

为解决水体因低碳氮比而导致脱氮效率差的问题,将颗粒聚己内酯(PCL)重新塑形为阶梯环状,研究其作为反硝化过程的生物膜载体与固相碳源的反硝化性能。结果表明,在静态实验中,平均反硝化速率为8.57 mg NO3-N/(L·h);反硝化过程为零级反应。连续填充床实验中,超过90%的硝酸盐可被去除,出水NO2-N质量浓度低于0.20 mg/L;出水NH3-N质量浓度略有上升;出水溶解性有机碳(DOC)先上升后降低至1 mg/L左右。电子扫描显微镜扫描显示,PCL阶梯环反应表面空隙率较高,表面生物膜以杆菌为主,反应后被明显腐蚀;液相色谱检测显示PCL阶梯环分子量反应前后略有下降,其结构未受到破坏;表明该材料适合作为反硝化反应的碳源的同时,又可以作为载体供微生物附着生长。     

基于改性凹凸棒土的强化混凝处理高藻低浊原水工艺

针对水厂低浊高藻水的处理难题,研究了改性凹凸棒土(改性凹土)联合聚合氯化铝(PAC)强化混凝的除藻除浊效果。设计实验原水条件为叶绿素a(chl-a)浓度为98.58~110.35μg/L,浊度(5.6±0.5)NTU。考察了PAC和改性凹土的复配投加量、混凝沉淀时间、pH、投加顺序、搅拌速率等工艺参数对Chl-a和浊度耦合去除效果的影响。结果表明,"PAC+改性凹土"对Chl-a和浊度的去除效果明显优于单投PAC的效果。当PAC投药量12 mg/L,改性凹土投药量10 mg/L,沉淀时间20 min时,对Chl-a和浊度的去除率可分别达到92.5%和89.2%,可至少减少40%的PAC投量,且形成的矾花密实,沉降速度快,去除效率高。最适pH范围为7~8。投加顺序应为先投加改性凹土,混合搅拌转数宜慢速,可控制为50 r/min。     

白云岩石漠化坡地土壤改良盆栽试验研究报道——以种植黑麦草为例

本文针对白云岩坡地土壤漏水、漏肥问题,通过对白云岩坡地土壤施用保水剂和活性炭,开展土壤改良的盆栽试验,探讨保水剂和活性炭对白云岩坡地土壤的理化性质和水分养分流失以及黑麦草生物量的影响。结果表明:(1)通过添加保水剂,可以有效改善土壤理化性质、减少水分渗漏,提高植物可利用水分。添加0.5%和1%的保水剂,渗漏水量和容重明显降低,孔隙度、土壤含水量、全氮、碱解氮、速效钾和有机质含量显著提高,总生物量分别比未添加保水剂处理增加了15.71%和22.79%。(2)添加活性炭,可以有效减少养分淋失,增加农作物产量,缓解白云岩坡地土壤"漏肥"问题。添加3%和5%的活性炭,土壤全氮、速效磷、速效钾和有机质含量显著增加,总生物量分别比不添加活性炭处理增加了42.55%和64.76%。(3)保水剂和活性炭的建议添加比例分别为1%和5%。保水剂和活性炭作为土壤改良剂,可以有效改善土壤物理结构,降低土壤水分渗漏量,减少养分漏失,提高作物产量,为白云岩石漠化坡地土壤的"漏水"和"漏肥"问题探寻一种新的解决途径,提高土地生产力。     

对我国环境行政复议制度的几点思考

现行环境行政复议制度存在的一些不足,阻碍了其在促进环保部门依法行政、维护群众合法环境权益方面作用的发挥,应当扩大享有环境行政复议申请资格的人员范围,规定环境行政复议简易程序,增强复议机构的独立性和提高复议工作人员的综合素质。     

扬州经济开发区发展循环经济的实践、对策和规划

扬州经济开发区通过国家生态工业示范园区的创建和国家循环经济试点工作，构建以工业共生、物质循环、自然和谐、宜业宜居为特征及资源节约型、环境友好型开发区。本文介绍了扬州经济开发区发展循环经济的实践情况，以“减量化、再利用、资源化”和“可持续性”原则为理念，分析了其循环经济发展存在的问题，并提出了相应对策和规划。     

改性甘蔗渣对Cu^2＋和Zn^2＋的吸附机理

研究了均苯四甲酸二酐（PMDA）和乙二胺四乙酸二酐（EDTAD）改性甘蔗渣对重金属离子Cu^2＋和Zn^2＋的吸附性能，包括吸附动力学和吸附等温线。结果表明，改性后的甘蔗渣对重金属离子Cu^2＋和Zn^2＋的吸附容量有显著提高，对Cu^2＋和Zn^2＋吸附等温线均符合Langmuir方程，吸附为单分子层吸附。根据Langmuir方程，PMDA和EDTAD改性甘蔗渣对Cu^2＋的吸附量分别为60．21和33．45mg／g，对Zn^2＋的吸附量分别是70．53和36．53mg／g。两种改性甘蔗渣对两种金属离子的吸附在30min内均可完成，用准二级吸附动力学方程模拟动力学过程得到较好的线性相关性。以EDTA溶液为洗脱剂对吸附Cu^2＋和Zn^2＋的改性甘蔗渣进行洗脱再生，再生的吸附剂可反复使用。     

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in biosolids from municipal wastewater treatment plants in China

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) along with methoxylated polybrominated diphenyl ethers (MeO-PBDEs) have been frequently identified as natural compounds in marine environment and also assumed as metabolites of PBDEs. In the present study, nine OH-PBDE, nine MeO-PBDE and 10 PBDE congeners were studied in the sewage sludge collected from 36 municipal wastewater treatment plants (WWTPs) in 27 cities of China. The results suggest that OH-PBDEs and PBDEs are ubiquitous in sewage sludge in China, however, methoxylated PBDEs were not detectable. Composition profiles of detected OH-PBDE congeners were different depending on the sampling location. ΣOH-PBDEs in WWTPs sludge ranged from 0.04 to 2.24 ng g^?1 dry weight (mean: 0.35 ng g^?1 dry weight). The total amount of the two most prominent congeners (6-OH-BDE-47 + 2′-OH-BDE-68) accounted for about 53.3–100% of the sum of all six identified congeners. A significant linear relationship was found between 6-OH-BDE-47 and 2′-OH-BDE-68. A distinct geographical distribution of ΣOH-PBDEs was observed with greater concentrations of OH-PBDEs at coastal areas than inland regions in China.     

Hexabromocyclododecanes in surface sediments and a sediment core from Rivers and Harbor in the northern Chinese city of Tianjin

In the present study, hexabromocyclododecanes (HBCDs) were investigated in the sediment from Haihe River (HR), Dagu Dainage Canal (DDC) and Tianjin Harbor (TH) at Bohai Bay using a total of 51 samples of surface sediments and a sediment core collected from May to September in 2010, and its diastereomer- and enantiomer-specific profiles were analyzed. The concentration of total HBCDs were generally high, with mean value and ranges of 31.0 and 1.35–634 ng g^?1 dw, respectively. The contamination followed the order of TH > DDC > HR. Higher levels (up to 634 ng g^?1 dw) occurred in the lower reach of HR and DDC located in an industrial area of Tianjin. This is the first time to report so high concentration of HBCDs in sediment in Southeast Asia. The γ-diastereomer dominated in most samples (44 out of 51), and this is in agreement with the diastereomer distribution pattern in industrial products, while α-HBCD was the dominant diastereomer in the other seven samples. However, only few samples exhibited γ-diastereomer ratio similar to that (75–89%) in technical products, indicating the inter-transformation and variable degradation of the different isomers. The high ratio of γ-diastereomer could be used as an indicator for fresh contamination input. Enantiomeric factors (EFs) of HBCD isomers in most of the samples were statistically different from technical products (p < 0.05), showing a trend of more easily enrichment of the (?)-HBCD-enantiomer compared to the (+)-HBCD-enantiomer. The δ- and ε-diastereomers were frequently detected but at low level. The HBCDs in the sediment core showed several peaks, and the greatest value occurred in 2005, when a plastic manufacture plant using HBCD was set up nearby.