Comparative evaluation of full‐scale UASB reactors treating alcohol distillery wastewaters in terms of performance and methanogenic activity

In this study, two full‐scale upflow anaerobic sludge blanket (UASB) reactors, namely TUASB and CUASB, at the wastewater treatment plants of the Tekirdaǧ Alcohol (Raki) and Canakkale Alcohol (Cognac) distilleries were investigated in terms of performance, acetoclastic methanogenic capacity and microbial composition. The results were compared with a previously studied other UASB reactor (IUASB) at the wastewater treatment plant of the Istanbul Alcohol (Raki) Distillery from which the two reactors (TUASB and CUASB) were seeded. The IUASB reactor performed well achieving COD removal efficiencies of no lower than 85% at organic logding rates (OLRs) in the range of 6–11 kg COD m⁻³ day⁻¹ between 1996 and 2001. During the last one year of operation, between 2000 and 2001, performance of the CUASB reactor in terms of COD removal efficiency was 70–80% at OLRs in a range of 1–4.5 kg COD m⁻³ day⁻¹ whereas it was 60–80% at OLRs in a range of 2.5–8.5 kg COD m⁻³ day⁻¹ in the TUASB reactor. At the end of year 2000, specific methanogenic activity (SMA) tests were carried out to determine potential loading capacity and optimum operating conditions of the IUASB, CUASB and TUASB reactors. The potential methane production (PMP) rates of the CUASB, IUASB and TUASB reactors were measured as 230 cm³ CH₄ gVSS⁻¹ day⁻¹, 350 cm³ CH₄ gVSS⁻¹ day⁻¹ and 376 cm³ CH₄ gVSS⁻¹ day⁻¹ respectively. When the PMP rates were compared with actual methane production (AMP) rates obtained from the three UASB reactors, AMP/PMP ratios were evaluated to be 0.18, 0.12 and 0.13 for CUASB, TUASB and IUASB reactors respectively. This showed that the CUASB, TUASB and IUASB reactors were using only 18%, 12% and 13% of their potential acetoclastic methanogenic capacity respectively. These results can be interpreted that the three UASB reactors were underloaded compared with their potential acetoclastic methanogenic capacities. It was, therefore, recommended that the three UASB reactors should be loaded at higher organic loading rates or sludge withdrawn in order to maintain an AMP/PMP ratio of 0.6–0.7, which can ensure desired reactor performance with safer operation. Results of epifluoresence microscopic examinations showed that the percentage of total autofluorescent methanogens was approximately 30% of the total population in sludges from the TUASB and IUASB reactors whereas it was 20% in sludge from the CUASB reactor. The two UASB reactors treating raki distillery wastewaters contained sludges having a higher percentage of autofluorescent methanogenic population and higher acetoclastic methanogenic activity. Copyright © 2004 Society of Chemical Industry     

A three-compartment model for micropollutants sorption in sludge: Methodological approach and insights

In sludge resulting from wastewater treatment, organic micropollutants sorb to particles and to dissolved/colloidal matter (DCM). Both interactions may influence their physical and biological fate throughout the wastewater treatment processes. To our knowledge, sludge has never been considered as a three-compartment matrix, in which micropollutants coexist in three states: freely dissolved, sorbed-to-particles and sorbed-to-DCM. A methodology is proposed to concomitantly determine equilibrium constants of sorption to particles (K_part) and to DCM (K_DCM). Polycyclic Aromatic Hydrocarbons (PAHs) were chosen as model compounds for the experiments. The logarithm of estimated equilibrium constants ranged from 3.1 to 4.3 and their usual correlation to PAH hydrophobicity was verified. Moreover, PAH affinities for particles and for DCM could be compared. Affinity for particles was found to be stronger, probably due to their physical and chemical characteristics. This work provided a useful tool to assess the freely dissolved, sorbed-to-particles and sorbed-to-DCM concentrations of contaminants, which are necessary to accurately predict their fate. Besides, guidelines to investigate the link between sorption and the fundamental concept of bioavailability were proposed.     

Capacity Region of a Class of Gaussian Cognitive Degraded Broadcast Channel

This paper studies the cognitive broadcast channel in which the primary user com- municates to the primary receiver, while the secondary user has noncausal knowledge of the primary radio＇s codeword and expects to communicate to two secondary receivers. Comparing with the existing cognitive radio channel which considers only one secondary receiver, cognitive broadcast channel studies the case that there are multiple secondary receivers. To this end, we investigate the fundamental limits of the performance of the Gaussian cognitive broadcast channel from the information theoretic perspective. Specifically, we derive the capacity region of the Gaussian cognitive degraded broadcast channel with weak interference.     

真空预压法在道路软基处理工程中的应用

以真空预压处理海相淤泥软基的工程为例，通过对真空预压施工工艺流程及监测数据的分析，得出：真空预压加固法是对海相淤泥地基行之有效的地基处理方法，其加固效果和经济效益明显，加固后固结度和工后沉降量都达到了设计要求。     

适应网络教育自动组卷算法的研究

针对网络教育开放性、自主性的特点,本文提出了适应于网络教育的以知识点为核心的自动组卷算法.在分析试题库层次结构和数据表属性设置的基础上,该算法把题型平均难度系数、题型个数作为主要控制目标,以包含题目题型作为主要条件筛选知识点,以此选择试题,而后对题目按知识点的各难度等级分类,从而按知识点选题组卷,并运用适当的组卷策略优化组卷结果.实验表明,该算法依据不同的组卷策略自动生成的试卷,组卷效率、成功率和知识点覆盖率均比较理想.     

纸质媒体生存危机探析

在综合分析国内外报纸的生存现状调查资料的基础上,提出传统纸质媒体所面临的生存危机：受众的大量流失是其市场生存的最大危机,广告收入的下降及发行成本的上升促使其采取减少发行量和报纸涨价的无奈选择,由此可能进入受众流失——广告收入下降——减少发行量——报纸涨价——更多的受众流失的恶性循环。此外互联网、手机等新媒体的迅猛发展将加速传统纸质媒体的衰微。     

废纸造纸污水处理污泥膨胀解决实例

结合某纸厂处理脱墨污水时发生污泥膨胀的实例,对温度、溶解氧和食微比等因素进行分析,得出过量PAM引起的泡沫和食微比过低导致污泥膨胀,并提出减少加药量、安装喷头和投加淀粉等解决措施。     

纸质家具设计的发展趋势研究

以纸质家具相对实木、藤、金属类家具具有质轻、环保、经济、舒适、时尚的优点为启示,论述纸质材料在家具设计行业中研发与应用的重要性。并在此基础上,提出了纸质这种"可持续性"材料应用在家具设计中,能够体现家具设计的环保新理念,并根据纸质家具目前还存在的一些缺点和未来欧洲家具设计发展方向,概括出纸质家具设计在未来几年内的发展趋势。