Long-term engineering properties of recycled plastic lumber used in pier construction

Plastic lumber manufactured using post consumer waste plastic has been proposed as an acceptable material for use in the construction of docks, piers and bulkheads and is touted to outlast conventional wood products due to its strength, durability and resistance to rot. This study examines the long-term engineering properties of plastic lumber manufactured using post consumer waste plastic (TRIMAX, Ronkonkoma, NY). Plastic lumber profiles were used in the decking of a pier built in West Meadow Creek, Old Field, NY during December 1995. Samples of plastic lumber were removed from the deck of the pier periodically over a two-year period and returned to the laboratory for testing. Results of engineering tests showed the in-plane compression modulus (260±30 MPa), dimensional stability and the Shore D surface hardness (60±2) of plastic lumber removed from the pier remained similar to or greater than their pre-placement values. In contrast, significant changes in the modulus of elasticity of plastic lumber were measured with prolonged weathering. The modulus of elasticity of plastic lumber initially decreased from 1370 Pa to 750 Pa following 12 months weathering, a decrease equal to 45% of its pre-placement value and then increased during the second year to close to its initial value. The high variability in the modulus of elasticity should restrict the use of plastic lumber profiles to non-load bearing structural applications.     

浅谈秸秆资源的综合利用

本文从避免减少秸秆的焚烧、秸秆入河的角度,简要介绍了秸秆资源的综合利用,从而减轻了对大气环境和水环境的污染和危害,提高了资源的综合利用.     

电极材料对电解法处理循环式准好氧垃圾填埋场渗滤液效果的影响研究

分别用3种不同材料电极（不锈钢、Ti／Pt和Ti／RuO2-IrO2）作阳极、石墨电极作阴极在同一条件下分别对循环式准好氧填埋垃圾场渗滤液进行电解处理对比研究。研究结果表明，随着电解时间的变化，渗滤液中的COD、BOD5、BOD5／COD、重金属离子浓度、色度和pH值均会发生改变。当电解时间为10—20min时，用上述3种电极作阳极电解均会出现渗滤液COD、BOD5、BOD5／COD增大的现象；当电解时间为30—40min时，用Ti／RuO2-IrO2或Ti／Pt电极作阳极电解均可使渗滤液的色度降为0；当电解时间为120min时，分别用3种电极作阳极电解都可使渗滤液中的COD、BOD5和重金属得到有效的去除，其中用Ti／RuO2-IrO2电极作阳极电解对COD、BOD5的去除效果最好：用Ti／Pt电极作阳极电解对Pb^2＋的去除效果最好。     

Controlled release, blind test of DNAPL remediation by ethanol flushing

A dense nonaqueous phase liquid (DNAPL) source zone was established within a sheet-pile isolated cell through a controlled release of perchloroethylene (PCE) to evaluate DNAPL remediation by in-situ cosolvent flushing. Ethanol was used as the cosolvent, and the main remedial mechanism was enhanced dissolution based on the phase behavior of the water-ethanol-PCE system. Based on the knowledge of the actual PCE volume introduced into the cell, it was estimated that 83 L of PCE were present at the start of the test. Over a 40-day period, 64% of the PCE was removed by flushing the cell with an alcohol solution of approximately 70% ethanol and 30% water. High removal efficiencies at the end of the test indicated that more PCE could have been removed had it been possible to continue the demonstration. The ethanol solution extracted from the cell was recycled during the test using activated carbon and air stripping treatment. Both of these treatment processes were successful in removing PCE for recycling purposes, with minimal impact on the ethanol content in the treated fluids. Results from pre- and post-flushing partitioning tracer tests overestimated the treatment performance. However, both of these tracer tests missed significant amounts of the PCE present, likely due to inaccessibility of the PCE. The tracer results suggest that some PCE was inaccessible to the ethanol solution which led to the inefficient PCE removal rates observed. The flux-averaged aqueous PCE concentrations measured in the post-flushing tracer test were reduced by a factor of 3 to 4 in the extraction wells that showed the highest PCE removal compared to those concentrations in the pre-flushing tracer test.     

从LCA角度评价塑料用品与木制用品对环境的影响

通过对一次性塑料与纸制用品（木制品）的评价研究的基础上，对木制品与塑料制品从生命周期评价（LCA）的角度上对问题作进一步的探讨和研究，得出结论为塑料制品为环保型产品。     

沉淀法回收聚苯乙烯泡沫塑料的工艺研究

研究沉淀法回收聚苯乙烯泡沫塑料(EPS)的工艺,利用石油裂解副产物为溶剂回收废旧聚苯乙烯泡沫塑料,以废治废,回收利用。溶剂低毒,对聚苯乙烯泡沫塑料溶解速度快,溶解量大,价廉易得。采用转式间歇投料并附加溶剂挥发分回收装置的工艺,溶剂回收率高,无二次污染,可循环使用。聚苯乙烯塑料(PS)回收率可达99%。     

我国纸包装废物产生特性和回收状况研究

纸包装被广泛应用于各个领域,消费量巨大,废物的产生量也巨大,但我国对其产生特性和回收体系研究较少。首先分析纸包装的生产量、消费量、废物产生量和回收量,指出我国纸包装废物回收率,远高于废纸的统计回收率;其次,综合分析纸包装废物的回收特性和回收体系状况,指出纸包装废物主要流向和关键环节;然后,对纸包装消费趋势进行预测,最后,提出纸包装废物回收存在的问题和对策措施。     

融入循环经济体系的滨海湿地资源开发思路探讨

滨海湿地是湿地的重要类型之一,其资源、生态、旅游、文化、教育、科研等多方面的潜在功能对社会、经济发展均有极其重要的作用。而中国滨海湿地遭受破坏的情况较为严重。当前,如何基于科学发展观,将滨海湿地纳入循环经济系统之中,更加合理地进行开发、保护,已成为关系到中国经济可持续发展的重要问题之一。文章基于对山东滨州地区典型滨海湿地资源开发实践的研究,结合中国其他地区湿地开发保护的经验教训,以循环经济理论为指导进而探讨适合中国国情的滨海湿地资源开发思路、模式,并在此基础上提出一些建议,以期能够对中国“十一五”时期的湿地开发、保护工作以及部分地区区域经济发展起到一定借鉴、推进作用。     

废纸造纸废水处理工程的设计与运行

文章针对废纸造纸生产中废水产生量大,SS、COD浓度较高的问题,将废纸造纸废水处理工程实践中的污水作为对象,研究一套废纸造纸废水回收利用的污水处理方法,减少再生纸造纸工业对环境的污染。实验结果和工程实践证明:利用混凝沉淀—活性污泥相结合工艺处理废纸造纸废水,达到一部分经物理处理后回收利用,一部分经生化处理后达标排放。采用该工艺处理效果好,SS去除率达99.7%、COD去除率达98.4%,且运行稳定,成本和一次性投资均较低,其排放废水水质满足《造纸工业水污染物排放标准》(GB3544-2001)中的排放要求。     

天津滨海新区再生资源产业发展对策

天津滨海新区再生资源产业以废弃物流通、加工利用为主营内容,具有补链特征与技术先进性,主要为滨海新区提供生产性服务。为了适应滨海新区发展所提出的要求,再生资源产业应不断提高资源供给能力,扩展服务对象,提高资源流通和集散能力,并挖掘向再制造产业延伸的潜力。建议尽快制定滨海新区再生资源产业发展规划和实施指导方案,实行优先采购制度,并鼓励再生资源企业参与社会回收体系的建立,完善再生资源产业运输和物流系统,不断提高产业的升级能力。