FIELD TESTING OF AN ICE-PRESERVING WINTER LAKE AERATION SYSTEM1

ABSTRACT: Artificial aeration is used to prevent winter fish kills due to oxygen depletion in ice-covered lakes. Conventional aeration by air bubble plumes and other techniques usually mixes the water column and produces hazardous open water in the ice cover. A non-mixing winter lake aeration system which creates a fish refuge was designed and field tested to oxygenate the water and maintain water temperature stratification in a lake such that no open water is created. The system uses a cascade aerator and has a design discharge and dissolved oxygen input rate of 85 1/s and 70 kg/d, respectively. Aerated water is discharged near mid-depth with minimum disturbance of the ambient water through a specially designed diffuser. The system was tested in a shallow 3 m deep lake of 17 ha surface area during two winters and was found to perform as expected. Significant photosynthetic production of dissolved oxygen under the ice-cover was also observed during snow-free periods.     

微孔盘曝气系统中悬浮填料挂膜特征研究

在微孔盘曝气系统中,针对悬浮填料挂膜过程,展开中试试验研究。试验结果表明,在HRT仅1h的连续流曝气系统中,悬浮填料挂膜快。曝气强度不同,悬浮填料挂膜特性和生物膜量以及对COD的去除效果相差很大。试验发现微孔盘曝气系统中悬浮填料的最适宜曝气强度范围为8～10m3/(m2·h),在此范围内,系统的溶解氧为3.9～5.2mg/L,生物膜量为3.3～3.5g/L,对COD的去除率在70%～80%。在上述基础上还对不同型号的悬浮填料进行了优选。     

扬水曝气器类型对分层水库藻类控制效果的影响

为优选扬水曝气器的类型以更经济有效地原位控藻,建立了基于Fluent软件的水库水动力与水质数值模拟方法,在不同温度梯度和水深条件下,预测了淹没式和非淹没式扬水曝气器对分层水库中藻类控制的效果. 以金盆水库扬水曝气水质改善工程为案例,对扬水曝气器外围流场和藻类混合迁移过程进行数值模拟. 结果显示,垂向流速和藻密度的模拟结果与实测数据吻合较好. 在典型的扬水曝气器运行条件下,水深分别为77.25、87.25和97.25 m时,淹没式和非淹没式扬水曝气器的外围流场均以顺时针环流为特征;淹没式扬水曝气器的环流发展较远,表层藻密度分别被削减了86.8%、88.2%、90.6%;扬水曝气器类型对藻密度削减率的影响不大. 采用淹没式扬水曝气器时,77.25、87.25和97.25 m水深下核心控藻区占整个流场区域的比例分别为39.71%、41.14%和42.73%,分别比非淹没式的高14.81%、8.95%和2.69%;藻类完全混合的时间分别为10、12和14 d,分别比非淹没式的少8、7和6 d. 不同季节和水深条件下的模拟结果表明,采用淹没式扬水曝气器,核心控藻区域较大,藻类混合较快.      

新型射流曝气器的研究与应用

成都绿水科技有限公司开发了一种新型射流曝气器,该射流曝气器与传统射流曝气器相比,在喷嘴形状、吸气室、喉管段、扩散管、导流片均有所创新。结合纯氧曝气,其已成功应用于重钢焦化厂焦化废水处理。结果表明:该设备充氧动力效率高,可达5.31 kg/(kW.h),仅用较少供氧量便可保证溶解氧浓度在2 mg/L以上,纯氧利用效率可达91%以上,且抗冲击负荷能力强,泡沫少,电耗、运行成本低。     

配备低压进样系统的GC-FID法测大气中的CO和CH_4

将自主研发的低压进样系统与GC-FID法相结合,解决了低压样气难以抽取进样的技术难题,实现了对SUMMA采样罐内低压样气中CO、CH4的分析.罐内样气压强大于30kPa情况下,该进样装置能将待测低压气体提升至常压状态并完成进样过程.本系统采用3个六通阀、5分子筛与TDX-01双柱实现O2、CO、CH4的有效分离.通过对5分子筛柱的反吹去除杂质组份,既保持基线平稳,又可缩短分析周期,提高效率.该分析系统CO、CH4的最低检出限分别为9.2×10-9、5.5×10-9.本分析系统与美国加州大学Irvine分校Donald R.Blake实验室针对CO、CH4比对的相对误差分别低3%和1%.     

A new method of inhibiting pollutant release from source water reservoir sediment by adding chemical stabilization agents combined with water-lifting aerator

A new method of adding chemical stabilization agents combined with water-lifting aerator can inhibit pollutant release from source water reservoir sediment effectively.