Steady state modeling of reactor-settler interaction

The work analyzes the interaction of a biological reactor and a settler coupled either via mass balance, exocellular polymer production or competition between flocculating and filamentous microorganisms. Pertinent experimental information is reviewed. Simple models are constructed to account for the necessary features of the interaction. The analysis reveals that chemical interaction should be correlated with sludge age and optimal operating conditions are derived. Biological interaction induces steady state multiplicity or coexistence of the two species. Recent observations of populations-shift dynamics are presented.     

扩张管嘴排泥管生产性试验研究

针对给水厂沉淀池普通穿孔排泥管起动困难易堵塞等问题,研制出一种新型排泥装置——扩张管嘴排泥管．先后进行了小试和中试,根据中试所得较优的一种扩张管嘴排泥管应用在生产性试验中,在同等条件下与普通穿孔管进行比较．扩张管嘴排泥管的流量系数是普通穿孔排泥管的4倍左右,且泥水含泥浓度约为普通穿孔管的1．4倍,池底积泥明显要少,相应可以延长排泥周期,节约水厂自用水量．     

分散式生活污水处理实训平台运行分析

分散式生活污水处理实训平台是在满足生活污水处理的前提下,用于相关专业学生及研究人员实验实训.该实训平台能够实现厌氧、缺氧、好氧生物处理,通过斜管沉淀,进入三级地下渗滤,出水水质的CODcr、NH3-N、SS和TP去除率分别达到92.2%、94.1%、87.6%和86.6%,平均浓度分别为10.13mg/L、0.79mg/L、9.97mg/L、0.23mg/L,各项指标均达到了《城镇污水处理厂污染物排放标准》(GB98918—2002)的一级A标准.     

一种水分散型多隔层混合室混合澄清萃取器的设计及操作性能

从减小液滴内传质阻力、提高两相间传质速率和改善混合室中两相的停留时间分布等方面对油分散型单混合室混合澄清萃取器(OWSMMS)的设计进行了改进,设计了水分散型多隔层混合室混合澄清萃取器(WOMMMS)以提高混合澄清萃取器的分离效率.在实验中分别应用OWSMMS和WOMMMS进行稀土分离,比较了它们的操作性能.在实验条件下,通量为1.46～2.92m~3/(m~2·h)时,轻/重稀土的相对分离效率比β_(qz)为1.426,相邻元素的相对分离效率比β_(ab)一般都大于1,说明WOMMMS的操作性能明显优于OWSMMS.     

斜管沉淀池应用于二沉池的弊端及解决措施

某污水厂因项目用地紧张,二次沉淀池采用斜管沉淀池。在运行中发现,存在斜管管顶积泥严重等弊端,不仅影响了后续的处理工序,而且增加了运行维护的工作量。为此,对相应弊端产生的原因进行了分析,并实施了有效地解决措施,进而使出水水质得到了明显改善。     

Comparative assessment of decoupling of biomass and hydraulic retention times in hydrogen production bioreactors

This study compared biological hydrogen production from glucose in two continuously stirred tank reactors (CSTRs) and two integrated biohydrogen reactor clarifier systems (IBRCSs) comprising CSTRs with gravity settlers to decouple the hydraulic retention time (HRT) from solids retention time (SRT). The four systems were operated at organic loading rates of 6.5–42.8 gCOD/L-d, and HRTs of 8–12 h. The SRT was maintained at 2 days in the two IBRCSs. The decoupling of SRT from HRT not only increased glucose conversion from 29–50% in the CSTR to 99.9% in the IBRCSs, but also the volumetric hydrogen production from 0.55–1.8 in the CSTRs to 2.4–9.6 L/L-d. Biomass yields in the two IBRCSs were 0.09 and 0.13 g VSS/g glucose converted, about 50% lower than the CSTR yields of 0.19 and 0.29 g VSS/g glucose converted. Hydrogen yield increased from 0.5–1.0 mol H₂/mol glucose converted in the CSTR to 2.8 mol H₂/mol glucose converted in the IBRCSs. The inverse relationship between hydrogen yield and biomass yield observed in this study implies that the hydrogen yield is maximized with the minimization of biomass yield, thus necessitating decoupling of SRT from HRT to ensure sufficient reactor biomass. DGGE analysis confirmed the specificity of the microbial culture in the IBRCSs with the high-hydrogen producing Clostridium species, as compared to the more diverse cultures in the CSTR.     

ACTIFLO~微砂加重絮凝斜管高效沉淀技术

针对北京市第九水厂原水低温、低浊及高藻的情况和出水要求,综合考虑实际工程情况和远期水质状况,采用ACTIFLO高效沉淀池工艺对该厂二期A处理线沉淀池进行改造,改造后处理能力由原来的25×104m3/d提高到34×104m3/d。调试期间的运行结果表明,ACTIFLO高效沉淀池对密云水库的低浊、高藻原水有稳定且良好的处理效果。     

平流沉淀池升级改造技术与应用

以莱芜市某水厂升级改造项目为基础,针对原水中藻类超标、水厂超负荷运行、滤池反冲洗周期短以及出水嗅味重等问题,提出了将平流沉淀池升级改造为气浮斜管复合池,并对气浮池和斜管沉淀池的改造设计要点进行了详细叙述.改造后水厂实际运行结果表明:将平流沉淀池升级改造为气浮斜管复合池可在一定程度上解决含藻水及超负荷运行的问题,并为类似实际工程提供技术数据和参考.     

混合澄清器设计参数的探讨

就影响混合澄清器设计参数的主要因素进行了探讨,阐述了设计过程确定参数的一般原则和方法,并提出了一些设计用的经验值。     

Cost reduction of the wastewater treatment plant operation by MPC based on modified ASM1 with two-step nitrification/denitrification model

The Activated Sludge Model No. 1 (ASM1) considers that nitrification and denitrification are single step processes and nitrite nitrogen (NO₂-N), which is an intermediate for the two processes, is not accounted for. The first part of this paper presents the development of an enhanced ASM1 with two step nitrification/denitrification processes and its implementation in the Benchmark Simulation Model No.1 wastewater treatment plant (WWTP). The secondary settler was considered to be reactive in order to achieve a better fit between the simulation model and the behavior of the real WWTP. The second part presents the investigation of Model Predictive Control approach for the advanced control of the WWTP. Two control strategies are implemented for the wastewater treatment plant and they are analyzed from the perspective of the benefits brought to the WWTP operation. The proposed control strategy shows a reduction of the operational costs and the improvement of the effluent quality index.