Microalgae cultivation and culture medium recycling by a two-stage cultivation system

Nutrients and water play an important role in microalgae cultivation. Using wastewater as a culture medium is a promising alternative to recycle nutrients and water, and for further developing microalgae-based products. In the present study, two species of microalgae, Chlorella sp. (high ammonia nitrogen tolerance) and Spirulina platensis (S. platensis, high growth rate), were cultured by using poultry wastewater through a two-stage cultivation system for algal biomass production. Ultrafiltration (UF) or centrifuge was used to harvest Chlorella sp. from the first cultivation stage and to recycle culture medium for S. platensis growth in the second cultivation stage. Results showed the two-stage cultivation system produced high microalgae biomass including 0.39 g·L^–1Chlorella sp. and 3.45 g·L^–1S. platensis in the first-stage and second-stage, respectively. In addition, the removal efficiencies of NH₄⁺ reached 19% and almost 100% in the first and the second stage, respectively. Total phosphorus (TP) removal reached 17% and 83%, and total organic carbon (TOC) removal reached 55% and 72% in the first and the second stage, respectively. UF and centrifuge can recycle 96.8% and 100% water, respectively. This study provides a new method for the combined of pure microalgae cultivation and wastewater treatment with culture medium recycling.

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Screening and identification of bacterial strain producing (R)-1-phenyl-1,2-Ethanediol by efficient whole-cell catalytic reduction system北大核心CSCD

(R)-1-Phenyl-1,2-ethanediol [(R)-PED] is an important chiral intermediate used to synthesize pharmaceutical intermediates. The production of (R)-PED is of great practical significance. A novel bacterial strain HBU-SI7 isolated from soil samples was screened using a-hydroxyacetophenone (2-HAP) as substrate, which is capable of enantioselective reduction of 2-HAP to (R)-PED. HBU-SI7 was identified as Rhodococcus sp. by bacterial morphological observation and 16S rDNA analysis. The analysis of whole-cell catalytic system showed that the bioconversion of 2-HAP reached 96.2% in the two-phase reaction system (dibutyl phthalate/phosphate buffer = 1/3, V/V) with the substrate concentration of 3.0 g/L, and 99.3% of e.e. for (R)-PED was achieved. A new enantio selective reduction system with the whole cells of Rhodococcus sp. was established for efficient production of (R)-PED, which has potential research and application values. © 2018 Science Press. All rights reserved.     

自动进样系统结合分光光度法快速测定水质中总磷

基于自动进样系统结合分光光度法,通过对波长、消解条件及显色条件的优化,建立了水中总磷的快速检测分析方法。在优化条件下,总磷的检出限为0.005 mg/L,测定下限为0.020 mg/L。对地表水、生活污水和工业废水3种不同基质的样品进行了加标测定,其回收率为95.0%~102%,相对标准偏差为0.5%~2.7%;与国标方法钼酸铵分光光度法测定水体中总磷进行比对研究,对国家有证标准样品、地表水、生活污水和工业废水测试的结果显示,方法相对偏差为0.4%~3.5%。该方法操作简单、快速、准确,可为应对突发环境事件中总磷的测定提供技术参考。     

浅析污泥膨胀的特性与控制对策

从丝状菌和絮凝菌的生长特性方面对活性污泥膨胀的特性及影响因素进行了分析研究,详细论述和分析了各种活性污泥膨胀控制措施。     

盐州变电站330kV主变压器带载能力不足分析

针对盐州330 kV变电站330 kV 1号、2号主变压器温升异常,带载能力不足问题,通过对变压器冷却器实体检查及温升实测值与理论计算对比分析,找出问题原因并提出了解决方案。分析及应用结果表明:变压器带载能力不足是由冷却器散热效率太低引起,更新冷却器后,变压器温升及带载能力达到额定要求,变压器恢复安全稳定运行。     

Effect of mixed slag aggregate replacement on performance of asphalt concrete

Journal of Material Cycles and Waste Management - In this study, two dosages of slag aggregate replacement were adopted to evaluate their effect on performance of asphalt concrete through lab tests...     

Distributions,origins, and health-risk assessment of nitrate in groundwater in typical alluvial-pluvial fans,North China Plain

Environmental Science and Pollution Research - High concentration of nitrate (NO3?) in groundwater is a major concern because of its complex origin and harmful effects on human health. This...     

模具工业先进制造技术特点及发展概况

重点介绍模具 CAD/ CAE/ CAM集成化、现代模具检测与加工设备 ,新型模具材料及表面处理技术、快速经济制模技术等模具先进制造技术的发展特点 ;分析探讨了模具工业的新的制造哲理与模式