Energy-efficient HVAC system through chillers’ capacity sizing for a library building

Heating, ventilating, and air-conditioning (HVAC) systems in commercial buildings consume the largest amount of energy. Recent surge in energy cost necessitates constant re-evaluation of HVAC system for most of the buildings. The objective of this study is to present the strategic approach on energy saving analysis of the HVAC system and chiller sizing optimization for a library building. Energy modeling code (eQUEST) for buildings simulation has been applied to verify and predict the long-term energy consumption of HVAC systems. To improve the accuracy of simulation results, the actual performance curves of the chillers and pumps were the inputs of curve fitting data from on-site field measurements data. Energy consumption data acquisition from the building energy management system (BEMS) for one year has been conducted comprehensively to calibrate energy modeling and to quantify energy saving results. The results revealed good agreement between energy modeling and BEMS data with the error of less than 10%. Besides, energy savings through the chillers’ sizing based on cooling load profile could be achieved satisfactorily by utilizing energy modeling by using the actual chiller performance curve. The energy saving for HVAC system can be obtained satisfactorily at the saving of 110,362 kWh per year. It is expected that the study will stimulate a more robust investigation of energy-efficient and cost-effective HVAC system specific for library buildings.     

干化床和芦苇床稳定污泥过程中的腐殖化特征简

通过现场实验,考查污泥干化床和污泥干化芦苇床稳定污泥过程中的腐殖质变化特征,重点分析了污泥腐殖化率和污泥腐殖化指数的变化情况。系统运行了3年,包括前2年的污泥负荷期和第3年的自然稳定期,检测分析在第3年进行。实验结果表明,污泥腐殖质含量历月变化不大,基本在1.1%~2.1%范围;总体上污泥的腐殖化率具有上升趋势,同一时间样品芦苇床中污泥的腐殖化率略高于干化床;污泥腐殖化指数呈上升趋势,但芦苇床略低于传统干化床;4—11月,干化床中的污泥腐殖化指数从0.079升高到0.742,芦苇床从0.042升高到0.715。经过3 y的稳定化处理,污泥的腐殖化程度和腐熟度得到有效提高。     

花生壳活性炭对水溶液中Cr(Ⅵ)的吸附性能

为提高花生壳对Cr(Ⅵ)的吸附性能,采用ZnCl2对花生壳进行改性,制得花生壳活性炭。通过批次吸附实验,考察了花生壳活性炭投加量、pH值、吸附时间等因素对Cr(Ⅵ)的吸附性能影响,同时,对吸附动力学、等温吸附特征和热力学进行了系统研究。结果表明,当吸附剂投加量为0.2 g时,在Cr(VI)初始浓度为20 mg/L、pH值为2.0条件下,吸附反应180 min后,花生壳活性炭对Cr(Ⅵ)的吸附率可维持在94.13%以上。吸附过程符合准二级动力学方程和Langmuir等温吸附模型;由吸附热力学方程计算得到吸附焓变(ΔH)>0,吸附自由能变(ΔG)<0,吸附熵变(ΔS)>0,表明花生壳活性炭对Cr(Ⅵ)的吸附过程是吸热和自发的。     

碳素纤维生态基技术对城市黑臭水体的修复效果

以碳素纤维(carbon fiber,CF)生态基为载体,处理南宁市朝阳溪黑臭河水,考察CF生态基在黑臭水体中的挂膜情况及其对污染物的去除效果。结果表明,CF生态基对污水中悬浮物有较强的吸附能力,在24 h内,CF实验组的浊度由原来的47.32 NTU降低为13.78 NTU;CF生态基生物亲和力强,易于挂膜,在黑臭水体中10 d内能形成较成熟的生物膜;在没有曝气情况下,CF生态基挂膜后对COD、TP、NH3-N和TN去除率分别达到76.00%、54.34%、90.73%和55.13%,是一种较有效的改善城市黑臭水体生态材料。     

The effect of experience on choosing where to go: an application to a choice experiment on forest recreation

The main objective of this paper is to investigate the impact of experience on the choice of visits to forests in a stated discrete choice experiment. Recent literature has indicated that experiences with the environmental services valuated may increase the respondents' certainty in their choice of hypothetical alternatives. We apply two indicators of experiences: the number of visits and the number of different forests visited during the last year. Applying the generalized multinomial logit model, we find that an increase in the number of visits to forests makes respondents' choices more predictable. However, the number of different forests visited reduces the predictability of choices. Furthermore, we investigate the relationship between respondents' experience of forest recreation and the self-reported choice certainty, controlling for respondents' social-demographics and other design characteristics. Finally, we show that self-reported choice certainty is positive correlated with the scale factor, as expected.     

印染废水回用处理的设计实例

采用"厌氧水解—缺氧—好氧—二次沉淀—超滤—反渗透"组合工艺进行印染废水的处理回用。运行结果表明,在平均进水COD和色度分别为508 mg/L和1695倍的情况下,COD和色度的总去除率分别为94.2%和98.8%,硬度不超过10 mg/L,铁、锰离子未检出,各项指标均达到HJ 471—2009《纺织染整工业废水治理工程技术规范》中的回用标准。GC-MS分析结果显示,二沉池出水中主要有机物成分复杂,超滤出水中有机物浓度有一定降低,反渗透出水中酸类全部被去除、苯胺类和烷烃类含量明显降低。从染色的白位沾色、手感、颜色和亮度等指标分析,回用水的染色效果远优于工业水。污水处理工程总投资约1×10~7元,设计规模4 500 m~3/d,回用水规模2 500 m~3/d,回用率55%,回用运行成本1.80元/m~3。     

三维荧光区域积分评估城市污水中溶解性有机物去除

以三维荧光技术为手段,结合荧光区域积分和聚类分析,考察某城市污水厂污水处理过程中溶解性有机物的去除状况。研究结果表明,采用三维荧光区域积分可以表征城市污水中易降解、可降解和难降解有机物相对含量的变化趋势,能够有效识别污水中溶解性有机物的指纹特征。城市污水中类蛋白等易降解物质含量约占总荧光物质的50%,在污水厂曝气池缺氧段,易降解基质被大量去除。曝气池顺水流方向约225 m处,溶解性有机物的去除已基本完成。三维荧光光谱中区域II和III的积分标准体积与TOC的皮尔森相关指数分别为0.964和0.970。和其他荧光指数相比,这2个区域的积分标准体积与TOC的相关度更高。     

Combined effects of deltamethrin, temperature and salinity on oxidative stress biomarkers and acetylcholinesterase activity in the black tiger shrimp (Penaeus monodon)

This study aimed to investigate the interactions of two abiotic factors (temperature and salinity) and deltamethrin (pyrethroid pesticide) exposure on some oxidative stress biomarkers as well as on acetylcholinesterase activity (AChE) in hepatopancreas, gills and muscle of black tiger shrimp (Penaeus monodon). A combination of three temperatures (24, 29 and 34 °C), two salinities (15 and 25 ppt), and the absence or presence of 0.1 μg L⁻¹ deltamethrin was applied on shrimp during 4 d under laboratory conditions. Lipid peroxidation level (LPO) and glutathione S-transferase activity (GST) were not affected by combined effect of temperature, salinity and deltamethrin in any of the studied tissues. Deltamethrin impaired other tested oxidative stress biomarkers, i.e. total glutathione (tGSH), catalase (CAT), glutathione peroxidase (GPx). tGSH level significantly increased in hepatopancreas due to deltamethrin exposure mainly at 34 °C, while pesticide effects on tGSH and CAT activity in gills were influenced by both temperature and salinity. In addition, GPx activity in hepatopancreas decreased after deltamethrin treatment mainly at 24 °C. Finally, AChE in muscle was strongly inhibited by deltamethrin at all tested temperatures and salinities. These novel findings demonstrate that interactions between abiotic factors and a commonly used pesticide exposure should be taken into account when analyzing some widespread biomarkers in black tiger shrimp.     

Isolation, identification and characterization of Bacillus amyloliquefaciens BZ-6, a bacterial isolate for enhancing oil recovery from oily sludge

Over 100 biosurfactant-producing microorganisms were isolated from oily sludge and petroleum-contaminated soil from Shengli oil field in north China. Sixteen of the bacterial isolates produced biosurfactants and reduced the surface tension of the growth medium from 71 to <30 mN m⁻¹ after 72 h of growth. These bacteria were used to treat oily sludge and the recovery efficiencies of oil from oily sludge were determined. The oil recovery efficiencies of different isolates ranged from 39% to 88%. Bacterial isolate BZ-6 was found to be the most efficient strain and the three phases (oil, water and sediment) were separated automatically after the sludge was treated with the culture medium of BZ-6. Based on morphological, physiological characteristics and molecular identification, isolate BZ-6 was identified as Bacillus amyloliquefaciens. The biosurfactant produced by isolate BZ-6 was purified and analyzed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry. There were four ion peaks representing four different fengycin A homologues.     

Influence of amendments on soil arsenic fractionation and phytoavailability by Pteris vittata L

Increasing availability of soil arsenic is of significance for accelerating phytoremediation efficiency of As-polluted sites. The effects of seven amendments, i.e., citrate, oxalate, EDTA, sodium polyacrylate (SPA), phosphate rock (PR), single superphosphate (SSP), and compost on fractionation and phytoavailability of soil As were investigated in lab culture experiment. The results showed that the addition of PR, SPA, EDTA or compost to soils significantly increased the concentration of NaHCO₃-extractable As over a 120 d incubation period compared with the control (amendment-free) soil. Then, the four amendments were selected to add to As-contaminated soil growing Pteris vittata. It was concluded that As accumulation by the fern increased significantly under the treatments of PR and SPA by 25% and 31%, respectively. For As fractionation in soil, SPA increased Fe-As significantly by 51% and PR increased Ca-As significantly by 18%, while both the two amendments reduced occluded-As by 16% and 19%, respectively. Adding PR and SPA in soil increased the activities of urease and neutral phosphatase resulting from the improvement the fertility and physical structure of the soil, which benefits plant growth and As absorption of P. vittata. The results of the research revealed that both PR and SPA were effective amendments for improving phytoremediation of As-contaminated sites by P. vittata.