Electricity generation from cattle dung using microbial fuel cell technology during anaerobic acidogenesis and the development of microbial populations

A microbial fuel cell (MFC) was constructed to investigate the possible generation of electricity using cattle dung as a substrate. After 30 days of operation, stable electricity was generated, and the maximum volumetric power density was 0.220 W/m(3). The total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) of the MFC reached 73.9±1.8% and 2.79±0.6%, respectively, after 120 days of operation. Acetate was the main metabolite in the anolyte, and other volatile fatty acids (VFAs) (propionate and butyrate) were present in minor amounts. The PCR-DGGE analysis indicated that the following five groups of microbes were present: Proteobacteria, Bacteroides, Chloroflexi, Actinobacteria and Firmicutes. Proteobacteria and Firmicutes were the dominant phyla in the sample; specifically, 36.3% and 24.2% of the sequences obtained were Proteobacteria and Firmicutes, respectively. Clostridium sp., Pseudomonas luteola and Ochrobactrum pseudogrignonense were the most dominant groups during the electricity generation process. The diversity of archaea dramatically decreased after 20 days of operation. The detected archaea were hydrogenotrophic methanogens, and the Methanobacterium genus disappeared during the periods of stable electricity generation via acidogenesis.     

AZ31B镁合金挤压工艺研究

在油炉中熔炼AZ31B镁合金 ,用熔剂保护 ,石墨模铸造圆锭。铸锭经 40 0℃× 1 2h的均匀化处理后 ,进行热挤压 ,其挤压温度为 40 0℃ ,挤压速度为 1～ 2 .5m/min ,挤压比为 1 0～ 45。共挤出了 1 1种规格的棒材、管材、型材 (工字型、槽型、角形、方形、T形等 ) ,挤压过程中均发生了动态再结晶 ,其抗拉强度σb 在 2 75～ 2 85MPa之间 ,屈服强度σ0 .2　在 2 2 0～ 2 2 5MPa之间 ,延伸率δ在 1 5 %～ 1 7%之间。所制订的工艺合理 ,挤压出的棒材、管材、型材有较好的力学性能     

Riboflavin-photosensitized degradation of atrazine in a freshwater environment

The effect of the photosensitizer riboflavin (0, 10, 50, 100 microM) on the fate of atrazine (10 mg/l) in a freshwater environment was studied. It was found that at 100 microM riboflavin significantly enhanced the degradation of atrazine and more than 80% of atrazine in a natural water environment was depleted in 72 h. The relative contribution of microbial assemblages and the freshwater matrix to the degradation of atrazine and the degradation kinetics of atrazine were compared under different experimental conditions. The products and pathways of atrazine transformation were studied with GC-MS and HPLC with a photodiode array detector. The results show that dealkylation and alkyl chain oxidation are involved in the degradation of atrazine.     

电子束半干法烟气净化技术

电子束烟气净化技术由于能够同时脱除烟气中的SO2 和NOx 而得到世界各国环保界的重视。传统的电子束烟气净化技术在工业应用中存在能耗高、副产品黏结严重、工作可靠性低等问题。新型电子束半干法烟气净化技术解决了传统工艺在工业化应用中存在的问题 ,可以在较小的辐照剂量下获得更为理想的烟气净化效果 ,提高了系统的工作可靠性 ,是一项工业应用前景十分广阔的环保技术。     

高效堆肥菌种的筛选及在城市污泥堆肥上的应用

分离筛选出了4株猪粪堆肥菌种,初步的分类鉴定表明它们均属于芽孢杆菌属.利用这些菌种制成混合菌剂,并进行城市污泥堆肥对比试验,结果显示,接菌处理在各项堆肥指标上明显优于未接菌的空白处理,自制菌与酵素菌在堆肥过程中具有非常相似的发酵能力,均能加快堆肥的升温速度,提高堆肥的最高温度,加快物料含水率的下降.说明自制菌不但可以应用于猪粪的堆肥发酵,在城市污泥高温堆肥方面也有很好的应用潜力.     

有机螯合剂与磷酸盐联合稳定垃圾焚烧飞灰中重金属的作用机理

为探讨二硫代氨基甲酸型有机螯合剂(FACAR)和重过磷酸钙(TSP)对垃圾焚烧飞灰中重金属Pb、Cd、Ni的稳定作用机制,对稳定前后的飞灰采用BCR连续提取法、X射线衍射(XRD)分析以及扫描电镜-能谱(SEM-EDS)联用等分析方法进行了表征。结果表明：投加质量分数5%的FACAR能有效稳定飞灰中Pb、Cd和Ni,其浸出浓度低于《生活垃圾填埋场污染控制标准》(GB 16889-2008)规定的浸出浓度限值;采用3% FACAR和3% TSP复配药剂处理,可使飞灰达到GB 16889-2008进场要求;经复合药剂稳定处理后的飞灰颗粒表面孔隙度明显降低,飞灰中Pb、Cd和Ni的形态均由不稳定态向稳定态转化。该复合稳定剂的稳定机制主要为螯合、共沉淀和吸附联合作用机制,其中,有机螯合剂中含硫官能团是影响重金属稳定的主要因素,且重金属具有优先与含硫官能团结合的特性。     

季铵盐改性聚偏氟乙烯膜抗污染性能及其对厌氧膜生物反应器微生物的潜在影响研究

将季铵盐(QAC)改性聚偏氟乙烯(PVDF)膜运用于厌氧膜生物反应器(AnMBR),评估了其抗污染性能,探讨了厌氧微生物在QAC/PVDF膜上短期暴露时的活性变化情况。结果表明,QAC/PVDF膜在AnMBR中清洗周期较长,说明QAC/PVDF膜可延缓AnMBR的膜污染形成;将厌氧微生物短期暴露于QAC/PVDF膜的环境中,QAC/PVDF膜对厌氧生物处理相关酶活性影响较小,不会引起厌氧微生物细胞破损或产甲烷性能下降。但随着直接接触的QAC浓度上升,厌氧微生物细胞破损比例上升,相关酶活性和产甲烷性能下降。     

电子束深度氧化烟气净化技术

介绍电子束烟气净化技术的特点 ,对传统电子束法与深度氧化法的反应原理、工艺流程进行了比较及分析 ,实验结果表明 ,电子束深度氧化烟气净化技术能耗低、可靠性高 ,是一种具有广阔工业应用前景的环保新技术。     

防闪络绝缘护套对鸟粪闪络防护效果的分析

作为一种新型鸟粪闪络防护措施,防闪络绝缘护套是通过降低绝缘子所承受的电压达到防护效果的,这种方法虽然在理论上可行,但其实际效果却还没有得到有效验证。因此,通过对鸟粪闪络的机理进行分析,建立架空输电线路鸟粪闪络的仿真模型和试验平台,验证防闪络绝缘护套对鸟粪闪络的防护效果。结果表明:只要厚度足够,绝缘护套能有效地阻止鸟粪污染造成的线路闪络事故的发生。     

克鲁伦河流域地下水饮用水水源中挥发性有机物的污染特征与风险评价

为明晰克鲁伦河流域地下水饮用水水源中挥发性有机物(volatile organic compounds,VOCs)的污染特征和风险水平,采用吹扫捕集气相色谱质谱联用仪对2020年8月在克鲁伦河流域采集的12个水样(7个地表水、5个地下水)进行分析,并采用美国国家环境保护局(US EPA)推荐的健康风险和生态风险评价模型对VOCs风险进行评价。结果表明:研究区域水体中VOCs污染程度较低,总体呈现地下水略高于地表水的状况;12个采样点均有VOCs检出,其中1,1-二氯乙烷、2,2-二氯丙烷、1,2-二氯丙烷、1,3-二氯丙烷、1,1-二氯乙烯检出率为100%;检出的VOCs中,1,3-二氯丙烷浓度最高,为1 186.44~4 677.97 ng/L,平均值为2 524.01 ng/L,邻二甲苯浓度最低,平均值仅为0.99 ng/L;各采样点无非致癌健康风险,致癌健康风险在可接受范围内,对水生生物有中等强度生态风险。