Nitrification in a packed bed bioreactor integrated into a marine recirculating maturation system under different substrate concentrations and flow rates

BACKGROUND: A packed bed bioreactor (PBBR) activated with an indigenous nitrifying bacterial consortia was developed and commercialized for rapid establishment of nitrification in brackish water and marine hatchery systems in the tropics. The present study evaluated nitrification in PBBR integrated into a Penaeus monodon recirculating maturation system under different substrate concentrations and flow rates. RESULTS: Instant nitrification was observed after integration of PBBR into the maturation system. TAN and NO₂‐N concentrations were always maintained below 0.5 mg L^?1 during operation. The TAN and NO₂‐N removal was significant (P < 0.001) in all the six reactor compartments of the PBBR having the substrates at initial concentrations of 2, 5 and 10 mg L^?1. The average volumetric TAN removal rates increased with flow rates from 43.51 (250 L h^?1) to 130.44 (2500 L h^?1) gTAN m^?3 day^?1 (P < 0.05). FISH analysis of the biofilms after 70 days of operation gave positive results with probes NSO 190 ((β ammonia oxidizers), NsV 443 (Nitrosospira spp.) NEU (halophilic Nitrosomonas), Ntspa 712 (Phylum Nitrospira) indicating stability of the consortia. CONCLUSION: The PBBR integrated into the P. monodon maturation system exhibited significant nitrification upon operation for 70 days as well as at different substrate concentrations and flow rates. This system can easily be integrated into marine and brackish water aquaculture systems, to establish instantaneous nitrification. Copyright © 2011 Society of Chemical Industry     

Characterization and Treatment of Leachates from Hong Kong Landfill Sites

Development of a large landfill site in the North-Eastern New Territories of Hong Kong, which will receive 25 million m³ of wastes during a life of about 13 years, must include the provision of a scheme to manage leachates which will arise in the tropical climate of the region.
The paper presents detailed results from a study commissioned by the Environmental Protection Department of the Hong Kong Government, to characterize and treat leachates generated by landfills in Hong Kong, in order to design a suitable management scheme. Field and laboratory trials which were carried out during 1989 showed that, although leachates from Hong Kong landfills have some specific characteristics (e.g. concentrations of amm.N to 5000 mg/l), they can be treated to high standards by aerobic biological processes.
As a result of these studies, a scheme has been designed which will provide a high degree of environmental protection in respect of leachate, as the landfill is developed.     

滤板施工技术比较

滤板是水处理滤池工艺的重要组成单元,文章对预制滤板和整体现场浇筑滤板的施工技术进行了比较说明,并得出了滤板施工技术选型结论。     

Nitrification and denitrification derived N2O production from a grassland soil under application of DCD and Actilith F2

The relative contribution of nitrification and denitrification to N₂O production was investigated by means of soil incubations with acetylene in a mixed clover/ryegrass sown sward 5 days after application of a mineral fertiliser (calcium ammonium nitrate) or an organic one (cattle slurry) with and without the addition of the nitrification inhibitor dicyandiamide (DCD) and the commercial slurry additive Actilith-F2. At this time, maximum field N₂O emissions were taking place. N₂O production by the slurry amended soil was twice as high as that of the mineral amended one. N₂O came in a greater proportion from nitrification rather than from denitrification in the slurry treatment, while for the mineral fertilisation most N₂O came from denitrification. The addition of DCD to slurry produced a decrease in N₂O production both from nitrification and denitrification. No reduction in N₂O losses was observed from addition of DCD to the mineral fertilisation, although DCD resulted effective in reducing the nitrification rate by 53% both in the slurry and the mineral fertilisation. Actilith F2 induced a high nitrification rate and N₂O production from denitrification was reduced while that from nitrification was not. This revised version was published online in August 2006 with corrections to the Cover Date.     

Development of microbial fuel cell with anoxic/oxic design for treatment of saline seafood wastewater and biological electricity generation

BACKGROUND: Sustainable technologies need to be developed to treat saline seafood wastewater (SSW) efficiently. This study focused on the feasibility of a continuously operated microbial fuel cell (MFC) with modified anoxic/oxic (A/O) architecture (A/O–MFC) for power generation and treatment of SSW simultaneously. RESULTS: Hydraulic retention time (HRT) was shown to have an impact on polarization and power output of the A/O–MFC and the maximum power density of 16.2 W m^?3 was obtained at a current density of 41.7 A m^?3 and HRT of 4.2 h. High salinity together with advective flow mode enabled a low and constant internal resistance of approximately 100 Ω throughout the experiments. Besides, pH of waste stream in both compartments was found always near neutral level. Increasing HRT could improve eliminability of soluble chemical oxygen demand (sCOD) and biological nitrification. CONCLUSIONS: This study provides a proof‐in‐concept demonstration to utilize an MFC for effective and sustainable treatment of SSW along with recovery of electrical energy. Copyright © 2010 Society of Chemical Industry     

短程硝化反硝化技术研究进展

综述了国内外短程硝化反硝化的技术进展。从短程硝化反硝化技术的影响因素、控制方式以及氨氧化菌的分子生物学研究等方面进行了分析,为在更普遍、更广泛的条件下实现短程硝化生物脱氮技术提供参考和支持。     

短程硝化反硝化A/SBR污水处理工艺的应用

介绍了短程硝化反硝化A/SBR污水处理工艺的原理、工艺流程及运行情况.通过实际运行证明:A/SBR工艺能满足氮肥企业污水处理的要求,进水COD在600 mg/L时,出口COD可控制在50 mg/L以下.     

小氮肥企业高氨氮废水处理的试验研究

针对小氮肥厂生产废水的排放现状及其对城市污水处理厂的影响 ,在试验的基础上提出了处理高含氨氮废水的空气吹脱—好氧硝化处理工艺 .空气吹脱可有效地去除解吸液中的氨氮 ,氨氮浓度由 1869.3mg/L降至 40 8.3mg/L ,去除率为 78% ;好氧生物硝化可有效地去除混合生产废水中的氨氮 ,氨氮浓度由 2 41mg/L降低为 2 3 .2mg/L ,去除率达 90 % ,达到国家二级排放标准     

MBBR中HRT与pH对短程硝化反硝化的影响

为了开发经济高效的生物脱氮工艺,在MBBR中进行了短程硝化反硝化的研究,考察了HRT与pH对短程硝化反硝化的影响。结果表明,在短程硝化反硝化过程中,在室温、不控制溶解氧的条件下,NH_4~+-N与COD去除率随着HRT的延长而增大,出水NO_2~--N随着HRT的延长先增大后减少,当HRT为8h时出水NO_2~--N最高;当pH由5增加到10时,COD去除率的变化较小,NH_4~+-N去除率和出水NO_2~--N则随着pH的增大先增大后减小,pH在8~9时对NH_4~+-N的处理效果最好,出水NO_2~--N最高。