This paper presents the performance results of a 366-day pilot-scale submerged membrane bioreactor (SMBR) for treating high-strength pharmaceutical wastewater. The study focuses on the growth properties of mixed liquo...This paper presents the performance results of a 366-day pilot-scale submerged membrane bioreactor (SMBR) for treating high-strength pharmaceutical wastewater. The study focuses on the growth properties of mixed liquor suspended solids (MLSS) in SMBR operated at high volumetric loading rates. The influences of MLSS on COD removal,sludge yield,oxygen utilization rates and sludge viscosity are studied. Results show that the bioreactor can be operated at higher volumetric loading rate with a low sludge yield. VSS/SS and observed sludge yield coefficient (Yo) present a decreasing trend with the decrease of hydraulic retention time (HRT) . Sludge oxygen utilization rate decreases with the increase of mixed liquor volatile suspended solids (MLVSS) . A mathematical model between sludge viscosity and MLSS is developed.展开更多
By considering the effect of suspended solid particles in the ordinary equations for two-dimension inviscid incompressible mixing layer, the Rayleigh equation and the modified Rayleigh equation are obtained. And then,...By considering the effect of suspended solid particles in the ordinary equations for two-dimension inviscid incompressible mixing layer, the Rayleigh equation and the modified Rayleigh equation are obtained. And then, by solving the corresponding eigen-value equations with numerical computational method, the relation curves between perturbation frequency and spacial growth rate of the mixing layer for the varying particle loading, ratio of particle velocity to fluid velocity and Stokes number are got. Sever al important conclusions on the effect of suspended solid particles on unstability of the mixing layer are presented in the end by analyzing all the relation curves.展开更多
Hourly mapping by a Geostationary Ocean Color Imager was used to reveal the spatial pattern and tidal variation of total suspended solids(TSS)over the Yangtze Bank in the Yellow and East China Seas during the winter.T...Hourly mapping by a Geostationary Ocean Color Imager was used to reveal the spatial pattern and tidal variation of total suspended solids(TSS)over the Yangtze Bank in the Yellow and East China Seas during the winter.The TSS form a tongueshaped structure,which decreases further offshore in a stepwise manner.The stepwise change is separated by two fronts of TSS,which are located near the 20-m and 50-m isobaths.The tidal variation of TSS concentration during the study period is evident and can be divided into three stages:decay,maintenance,and growth.Compared with the relatively stationary TSS during the maintenance stage,drastic changes exist during the decay and growth stages.In terms of tide-induced mixing,the dynamic analysis shows that both the topography and the tidal currents play an important role in the spatio-temporal variation of TSS during the tidal period.In particular,spatial distribution is primarily determined by the topography,whereas the temporal variations in tidal scale are determined by the tidal currents.展开更多
基金Sponsored by the Natural Science Foundation of Heilongjiang Province(Grant No.e2007-04)
文摘This paper presents the performance results of a 366-day pilot-scale submerged membrane bioreactor (SMBR) for treating high-strength pharmaceutical wastewater. The study focuses on the growth properties of mixed liquor suspended solids (MLSS) in SMBR operated at high volumetric loading rates. The influences of MLSS on COD removal,sludge yield,oxygen utilization rates and sludge viscosity are studied. Results show that the bioreactor can be operated at higher volumetric loading rate with a low sludge yield. VSS/SS and observed sludge yield coefficient (Yo) present a decreasing trend with the decrease of hydraulic retention time (HRT) . Sludge oxygen utilization rate decreases with the increase of mixed liquor volatile suspended solids (MLVSS) . A mathematical model between sludge viscosity and MLSS is developed.
文摘By considering the effect of suspended solid particles in the ordinary equations for two-dimension inviscid incompressible mixing layer, the Rayleigh equation and the modified Rayleigh equation are obtained. And then, by solving the corresponding eigen-value equations with numerical computational method, the relation curves between perturbation frequency and spacial growth rate of the mixing layer for the varying particle loading, ratio of particle velocity to fluid velocity and Stokes number are got. Sever al important conclusions on the effect of suspended solid particles on unstability of the mixing layer are presented in the end by analyzing all the relation curves.
基金supported by the National Key Research&Development Program of China(Grant No.2016YFC1401603)the NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(Grant No.U1609201)the National Natural Science Foundation of China(Grant No.41621064)。
文摘Hourly mapping by a Geostationary Ocean Color Imager was used to reveal the spatial pattern and tidal variation of total suspended solids(TSS)over the Yangtze Bank in the Yellow and East China Seas during the winter.The TSS form a tongueshaped structure,which decreases further offshore in a stepwise manner.The stepwise change is separated by two fronts of TSS,which are located near the 20-m and 50-m isobaths.The tidal variation of TSS concentration during the study period is evident and can be divided into three stages:decay,maintenance,and growth.Compared with the relatively stationary TSS during the maintenance stage,drastic changes exist during the decay and growth stages.In terms of tide-induced mixing,the dynamic analysis shows that both the topography and the tidal currents play an important role in the spatio-temporal variation of TSS during the tidal period.In particular,spatial distribution is primarily determined by the topography,whereas the temporal variations in tidal scale are determined by the tidal currents.
