Hydraulic Retention Time Influence on Improving Flocculation in the Activated Sludge Processes Through Polyelectrolytes

Hydraulic retention time (HRT) influence improving sludge flocculation with adding the polyelectrolytes (non-ionic, anionic, and cationic) was studied on an activated sludge (AS) system fed with synthetic domestic wastewater (SDW), dairy industry wastewater (DIW), and caramel industry wastewater (CIW). The sludge volumetric index, food/microorganism ratio (F/M), and mixed liquor volatile suspended solids at different HRTs (6, 8 and 10 h) were monitored on an experimental model. Results showed that both SDW and IW had the best sludge flocculation conditions at 8 h and 100 mL of non-ionic polyelectrolyte (0.2 mg L^?1). In addition, this phenomenon reached the organic matter removal efficiencies of 95.9, 95.7, and 94.2% for SDW, DIW, and CIW, respectively. Therefore, optimum HRT increased the organic matter removal efficiencies by 10%, sludge concentration by 37% (22–55%), and F/M ratio by 70%. Moreover, the polyelectrolytes used in AS improved the sludge flocculation by 2.9 times.     

工厂化两年养三茬成鳖新技术简介

为了提高养鳖经济效益,除了要抓好生产技术和销售外,如何缩短养殖周期,提高现有设备的利用率,已成为提高养鳖效益的重要途径。现把通过多年实践的工厂化两年养三茬成鳖新技术介绍如下,供有条件的地方参考应用。一、两年养三连成鳖的基本条件1．温室要求保温好,有供热供水条件（水质要附合养殖标准）。2.鳖池不宜太大,一般在25平方米,池深50厘米,水深35厘米,他中设饲料台（饲料台可用优质水泥瓦,不能用石棉瓦向采用无涉或沙网结合养殖,可在池中挂几趟无结网片作隐蔽物。3往排水方便C二、两年养三茬成鳖的工艺流程所谓两年养王茬…     

Comparison of larval thermal maxima between <Emphasis Type="Italic">Fundulus heteroclitus</Emphasis> and <Emphasis Type="Italic">F. grandis</Emphasis>

Fundulus heteroclitus and F. grandis are resident salt marsh fishes that overlap in distribution over a narrow range in northeastern Florida. The objective of the present study was to examine whether the limits of the species’ ranges could be explained by differences in thermal tolerance. Two populations of each species were collected and then spawned in the laboratory, and 9-day-old larvae were used for critical thermal maxima trials. Mean LOE temperatures of larvae ranged from 43.04 to 43.65°C and showed little difference between species. Therefore, differences in high temperatures experienced cannot account for the differences of the distributions of the two species. Condition-specific competition may play a greater role in determining the observed range of the two species.     

板栗壳色素的提取研究进展

板栗壳色素是一种天然色素,具有一定的抗氧化和抑菌作用。综述了板栗壳色素的理化性质,重点介绍了板栗壳色素的提取方法,展望了板栗色素的应用前景。     

现代农业技术推广的新实践

本文介绍了贵池区农技推广机构在引导传统农业向现代农业转变过程中,狠抓新品种,新技术推广应用,推广新技术60项以上,为农业增效、农民增收做了重要贡献。     

鲁中南山地刺槐萌生更新林经济效果评价

采用企业动态经济评价方法对刺槐萌生林不同轮伐期的经济效果进行了评价；按ＮＰＶ最大、ＩＲＲ最大确定了林分经济成熟龄；通过敏感性分析确定了经济成熟龄区间。     

基于检测技术和PLC的窖储白菜自动控制系统

随着农业生产的飞速发展,大规模的窖储白菜已出现在农村的生产中.降低白菜在窖内的损耗率已成为实际农业生产生活的重要问题.由于PLC具有可靠性高、便于扩展等特点,已逐渐代替了传统继电器控制的方式,检测技术和PLC应用于白菜窖储系统可实现该系统的功能要求.为此,介绍了检测技术和PLC在白菜窖储控制系统中的作用与功能的实现.