Properties and effects of remaining carbon from waste plastics gasifying on iron scale reduction

The carbonous activities of three kinds of carbon-bearing materials gasified from plastics were tested with coal coke as reference. The results showed that the carbonous activities of these remaining carbon-bearing materials were higher than that of coal-coke. Besides, the fractal analyses showed that the porosities of remaining carbon-bearing materials were higher than that of coal-coke. It revealed that these kinds of remaining carbon-bearing materials are conducive to improve the kinetics conditions of gas-solid phase reaction in iron scale reduction.     

废旧塑料的综合利用

近年来 ,治理“白色污染”、消灭“白色公害”已成为全球的共识 ,从废旧塑料的最终处置、直接再生利用、改性再生利用、热分解以及与其他材料复合等几个方面综述了废旧塑料的综合利用途径 ,其中废旧塑料和其他材料复合的再生利用技术有很好的发展前途 ,将成为今后研究的新热点     

废旧塑料综合利用技术的应用

废旧塑料的回收利用是环境污染控制所面临的一个重要课题,近年来,人们在这方面进行了大量的研究工作,取得了很多成果.详细叙述了国内外废旧塑料回收处理的方法,分析了我国在废旧塑料回收利用方面的现状及存在的问题,并对如何进一步开展废旧塑料回收利用工作提出了一系列切实可行的建议.     

废PE塑料溶剂法制氧化聚乙烯蜡

研究了在不同溶剂中以聚乙烯废塑料制高附加值氧化聚乙烯蜡产品的方法,测定了所得产物的分子量、酸值、软化点,并用IR考察了含氧基团。结果表明,溶剂A体系中能制备出颜色、分子量、酸值合格的低分子量氧化聚乙烯蜡,产品软化点在101～110℃,相对分子质量为1500,3000,酸值是12。以废塑料包装为原料,氧气做氧化剂下制得的氧化聚乙烯蜡的酸值最高。     

废旧塑料的处理工艺

介绍了当前国内外几种处理和利用废旧塑料的方法，特别对废旧塑料掩埋、再生、回收焚烧、热裂解制造燃料油和化学品的技术和存在的问题作了重点探讨。     

提高废旧塑料再生产品品质的预处理技术

废旧塑料是一种很有价值的可回收利用资源,经过再生可制取高品质塑材制品。但目前因塑料种类、颜色等原因,难有统一、合适的预处理技术,从而导致废旧塑料回收率低和塑材产品品质低等问题。针对废旧塑料的分选、破碎、清洗预处理技术影响塑材产品品质因素进行研究,重点考察破碎料粒度与氯乙烯(VCM)含量对再生塑料物化性质的多因素影响,实验结果表明,PVC型材产品杂质粒子数≤12个/900cm2,优于国标GB5761-1993相应的SG3型号优等品要求的16个/900cm2,且水循环利用率大于90%,环保效益好,具有极大的推广价值。     

废旧塑料的简易分类方法

塑料制品因其具有质量轻、外观美、加工方便、经济实用等特点而颇受人们青睐,广泛用于各行各业和日常生活用品中,但塑料制品的大量使用也给环境造成了严重污染,消除塑料污染的最积极的办法是对废旧塑料进行回收再利用。塑料种类繁多,不同类别的塑料性质和用途都不相同。介绍几种塑料分类的简易方法,以利于废旧塑料的回收利用。     

废弃热固塑料回收利用对策研究

随着电子产品、汽车报废高峰期的到来，作为其基本材料的热固性塑料的废弃量增长迅速。通过对国内外废弃热固塑料资源化技术进行分析，可以发现目前废弃热固塑料资源化存在的主要问题是收集困难，分类辨识技术低。由于废弃热固塑料的来源存在明显差异，在其回收体系中分别采用P-R模式、D-R模式和P-C-R模式，对不同来源的废弃热固塑料进行回收；并通过制定经济激励措施，细化并强制执行塑料分类标识标准，规范再生行业，加快废弃塑料分类辨识技术研发等对策来促进废弃热固塑料的资源化。     

不同含固率下零价铁提升厨余垃圾高温厌氧消化产沼体系运行稳定性研究

相比中温（35 ℃）厌氧消化,高温（55 ℃）厌氧消化中微生物代谢活性强,处理效率高,且无害化水平高,适合厨余垃圾的资源化处理及 利用.但由于厨余垃圾易降解,有机质含量高,水解速率快,极易在厌氧消化前期出现酸积累现象,这种现象在高温厌氧消化中更为显著,从而严重制约着高温厌氧消化的应用.本研究探究了零价铁（ZVI）对高温厌氧消化过程酸化现象的消除和控制,并对投加ZVI后不同含固率下 厌氧反应器严重酸化现象缓和效果进行评价.结果表明,高温条件下含固率为4%、6%的反应器在ZVI的促进作用下很快恢复产沼,甲烷产率相较低负荷反应器分别提高了52.05%、10.51%.含固率为8%的投加ZVI反应器在经历一个月的延滞期后也消除了“过酸化”,甲烷含量稳定在60%以上, 甲烷产率达到270.40 mL·g^-1.以加ZVI反应器沼液作为接种物的H-ICS反应器能够降低氢分压,但未能消除“过酸化”.含固率为10%的反应器在反应结束后仍处于酸化状态.高通量测序结果表明,所有外加ZVI的反应器中嗜氢产甲烷菌是绝对的优势菌.在恢复产沼的H-ZVI反应器以细菌Defluviitoga产生的乙酸盐、CO₂、H₂和丁酸转化来的乙酸为底物,嗜氢产甲烷菌Methanothermobacter作为唯一优势产甲烷古菌,与互营乙酸氧化菌Syntrophaceticus相互作用,实现互营乙酸氧化产甲烷（SAO-HM）途径,恢复产甲烷代谢.     

利用零价铁还原土壤中硝基苯类化合物的研究

利用零价铁(ZVI,Fe0)还原技术,对受2-硝基甲苯(OMNB)和2-氯硝基苯(OCNB)这2种硝基苯类化合物污染土壤的修复进行了研究.实验结果表明,在常温常压下,ZVI可有效地将土壤中的OMNB和OCNB还原成相应的苯胺类化合物,当2种硝基苯化合物在土壤中的含量均约为2.5×10-6 mol·g-1,ZVI加入量为25 mg·g-1,于25℃下反应6h,OMNB的还原率可达到97%,OCNB的还原率则高达100%;ZVI对OCNB的还原效率比OMNB稍高;这2种硝基苯类化合物的还原率均随反应时间的延长、ZVI用量的增加、温度的升高而升高,特别是当土壤初始pH值控制在偏酸性时更有利于还原反应的进行.此外,根据实验结果和相关的理论计算对ZVI还原硝基苯类化合物的反应机理进行了初步探讨.     

日中构建办公设备废塑料的跨境循环

介绍了日本理光公司生产的办公设备废塑料的原料再生利用,及其在中国跨境循环利用的背景程和流程,指出将国内处理完结型局部再生利用系统和国际循环完结型全面再生利用系统融合驱动是促进资源环境可持续性发展的有效途径。     

存余垃圾中废旧塑料性能演变及资源转化探讨

通过对全国范围内不同地域填埋场中存余垃圾组分含量以及存余垃圾中废旧塑料性能变化进行分析,发现存余垃圾中塑料占比较高,且填埋时间小于7a时,其力学及热学性能与未经填埋处理的原生废旧塑料性能基本无差异,具有较高的资源属性,但污染程度较高,难以直接进行高值化利用.文章进一步分析了国内现有清洁提质和处理处置技术,并针对存余垃圾中废旧塑料特性,提出一条由多效组合洁净技术与直接挤压成型工艺相结合的新型适用性清洁与高值化技术路线.     

Removal of arsenate and arsenite from aqueous solution by waste cast iron

The removal of As(III) and As(V) from aqueous solution was investigated using waste cast iron, which is a byproduct of the iron casting process in foundries. Two types of waste cast iron were used in the experiment: grind precipitate dust (GPD) and cast iron shot (CIS). The X-ray diffraction analysis indicated the presence of Fe0 on GPD and CIS. Batch experiments were performed under different concentrations of As(III) and As(V) and at various initial pH levels. Results showed that waste cast iron was effective in the removal of arsenic. The adsorption isotherm study indicated that the Langmuir isotherm was better than the Freundlich isotherm at describing the experimental result. In the adsorption of both As(III) and As(V), the adsorption capacity of GPD was greater than CIS, mainly due to the fact that GPD had higher surface area and weight percent of Fe than CIS. Results also indicated the removal of As(III) and As(V) by GPD and CIS was influenced by the initial solution pH, generally decreasing with increasing pH from 3.0 to 10.5. In addition, both GPD and CIS were more effective at the removal of As(III) than As(V) under given experimental conditions. This study demonstrates that waste cast iron has potential as a reactive material to treat wastewater and groundwater containing arsenic.     

废铁屑强化污泥厌氧消化产甲烷可行性分析

有关全球气候变化的《巴黎协定》落槌,预示着污水处理追求碳中和运行的时代已经来临.碳中和狭义理解即能源自给自足,这就要求污水处理厂应最大程度转化污水中有机物或产生的剩余污泥所蕴含的有机能源,并将其生成可再生能源——甲烷.然而,剩余污泥能源转化率较低一直都是限制厌氧消化技术广为应用的瓶颈.在污泥预处理技术之外,向厌氧消化系统中投加废铁屑强化甲烷生产有望成为另一个提高能源转化率的突破口,继而实现"以废促能、变废为宝"的目的.本综述从铁腐蚀析氢现象入手,在描述铁腐蚀析氢原理、析出H2对产CH4过程影响的基础上,对铁在厌氧系统ORP减少方面的作用、对厌氧微生物生理、生化特性的影响、对涉及微生物酶活的影响等进行了全面的介绍.最后,还通过生命周期评估(LCA)评价了基于废铁屑的污泥厌氧消化技术对环境的影响及经济合理性.     

进口废塑料清洁程度定量化合格评定方法的探讨

目前国内对进口废塑料清洁程度的合格评定,长期以来一直采取感官检验的定性方法,引起了较多争议。以《进口可用作原料的固体废物环境保护控制标准——废塑料》（GB16487,12）为依据,分析了GB16487．12对进口废塑料清洁程度进行规定的原因,并在此基础上探讨了对进口废塑料清洁程度采取定量化的合格评定原理,提出参照《一般工业固体废物贮存、处置场污染控制标准》（GB18599）和《生活垃圾填埋污染控制标准》（GB16889）对进口废塑料清洁程度制定定量化限量要求,并建议尽快修订现行国家标准《进口可用作原料的固体废物环境保护控制标准——废塑料》。     

Enhancing short-term ethanol-type fermentation of waste activated sludge by adding saccharomycetes and the implications for bioenergy and resource recovery

Ethanol-type sludge fermentation has recently attracted much attention because it can enhance direct interspecies electron transfer and thus improve the anaerobic digestion of waste activated sludge(WAS). In this paper, the enhancement of short-term ethanol-type fermentation of WAS via adding Saccharomyces was investigated. The experimental results show that the maximum ethanol production of 1030.8 ± 20.6 mg/L was achieved, with the optimum fermentation conditions of a p H of 5.1, temperature of...     

花卉秸秆和牛粪联合堆肥的中试研究

以花卉废物和牛粪为原料 ,进行了温度反馈的通气量控制联合堆肥的中试研究 .一次发酵采用静态好氧床进行 ,过程控制采用温度反馈通气量控制方法 ,周期 2 0天 ;二次腐熟采用周期性翻堆 ,周期 4 0天 .试验分析了堆肥过程中堆体温度、水分、pH值、有机质、湿重、干重、体积、湿容重、干容重等指标随时间的变化特征 ,结果表明 :采用温度反馈通气量控制的静态好氧堆肥技术进行花卉废物和牛粪的联合堆肥可以有效控制堆肥过程 ,实现有机物料的快速稳定和去除水分 .     

A strategy for enhancing anaerobic digestion of waste activated sludge: Driving anodic oxidation by adding nitrate into microbial electrolysis cell

Cathodic reduction of CO₂ and anodic oxidation of organic matters are crucial to methane-producing microbial electrolysis cell (MEC) applied in anaerobic digestion of waste activated sludge. However, cathodic CO₂ reduction is usually restrained by slow metabolism rates of H₂-utilizing methanogens and low electron-capturing capacity of CO₂, which consequently slows down the anodic oxidation that participates to sludge disintegration. Herein, a strategy with adding nitrate as electron acceptor to foster electronic transfer between the anode and cathode was proposed to improve anodic oxidation. Results showed that the average efficiency of anodic oxidation in the nitrate-added MEC increased by 55.9%. Accordingly, volatile suspended solid removal efficiency in the nitrate-added MEC was 21.9% higher than that of control MEC. Although the initial cumulative methane production in the nitrate-added MEC was lower than that of control MEC, the cumulative methane production in 24?days was 8.9% higher. Fourier transform infrared spectroscopy analysis indicated that anodic oxidation of MEC with nitrate accelerated the disintegration of sludge flocs and cell walls. Calculation on current signal further revealed that anodic oxidation driven by cathodic nitrate reduction was the main mechanism responsible for the improved sludge digestion.     

Effects of adding bulking agents on the biodrying of kitchen waste and the odor emissions produced

The effects of adding a bulking agent on the performance and odor emissions(ammonia and eight sulfur-containing odorous compounds) when biodrying kitchen waste were investigated. Three treatments were considered: the addition of either cornstalks(CS) or wood peat(WP) to kitchen waste as a bulking agent before biodrying, and a control treatment(CK). The water-removal rates for CK, CS, and WP treatments were 0.35, 0.56, and0.43 kg/kg, respectively. Addition of bulking agents to kitchen waste produced less leachate,higher moisture-removal rates, and lower consumption of volatile solids. The CS treatment had the highest biodrying index(4.07), and those for the WP and CK treatments were 3.67 and 1.97, respectively. Adding cornstalks or wood peat decreased NH3 emissions by 55.8%and 71.7%, respectively. Total sulfur losses were 3.6%–21.6% after 21 days biodrying, and H2 S and Me2 SS were the main( 95%) sulfur compounds released. The smallest amounts of sulfur-containing odorous compounds were emitted when cornstalks were added, and adding cornstalks and wood peat decreased total sulfur losses by 50.6%–64.8%.     

甘油投加对餐厨垃圾厌氧产酸性能的影响

餐厨垃圾厌氧发酵产生的挥发性脂肪酸（VFAs）可以作为合成聚羟基脂肪酸酯（PHA）的底物,PHA的性能与VFAs的组成密切相关.为改善PHA产品的性能,本文研究了甘油投加对餐厨垃圾产酸性能的影响.在餐厨垃圾厌氧消化半连续流反应器运行稳定的基础上,探讨了不同C/N对厌氧发酵有机物转化及VFAs产量和组成的影响.结果表明,投加甘油会降低发酵体系的pH,提高VFAs的产量,相比于对照组,C/N比为25/1时,VFAs产量提高了10.3%.C/N10.69/1（对照组）、15/1、20/1和25/1时,发酵液奇数碳VFAs所占总VFAs的比例分别为54.23%、61.16%、64.78%和66.79%.甘油的投加可以提升丙酸、戊酸等奇数碳VFAs所占比例,有利于改善PHA产品性能.