建筑给水排水工程论文
摘要：在采用SMSBR处理焦化废水的建筑给水排水工程论文过程中，通过对污泥进行终端过滤来反映膜污染机理，着重考察了过滤过程中的建筑给水排水工程论文阻力分布，并通过标准堵塞过滤定律和沉积过滤定律来拟合膜过滤过程，从而确定了膜污染的控制因素。污泥的阻力分布试验表明，沉积层阻力占总阻力的90%以上，并随压力的升高而增大，而内部污染阻力所占比例最小；污泥的终端过滤过程严格符合沉积过滤定律，即使在过滤初期也不受堵塞过滤的控制，这与阻力分布的结果相对应；污泥在终端过滤过程中膜的相对通量随过滤时间呈指数衰减趋势，并在几分钟内就达到相对稳定值，且低压对应较高的相对通量，但通量衰减指数和压力之间没有相关性；污泥的压密指数为0.7015。
关键词：SMSBR 焦化废水 膜污染机理 终端过滤
中图分类号：TU991.2
文献标识码：A
文章编号：1000-4602(2002)04-0005-05
Mechanism of Membrane Fouling in Coke Wastewater
Treatment bySubmerged Membra ne Sequencing Batch Reactor
LI
Chun jie1, GENG Yan2, ZHOU Qi2, GU Guowei2
(1.School of Environmental Science and
Engineering,Shanghai Jiaotong University, Shanghai
200240,China;
2.State Key Lab of Pollution Control and Resource
Reuse, Tongji University,Shanghai 200092,China)
Abstract：In coke wastewater treatment by submerged
membrane sequencing batch reactor (SMSBR),the mechanism of membrane
fouling was studied by means of dead-end filtration of activated
sludge.The study focused on the resistance distribution in filtra
tion and the use of standard blocking filtration law and cake
filtration law to fit in with the membrane filtration,and thus
determining the factors that control the membrane fouling.The test
on resistance distribution showed that the cake resistance makes up
over 90% of total resistance and is increased with the rising of
pressure,while the internal fouling resistance has the least
proportion.The dead-end filtration of sludge is in strict conformity
with the cake filtration law and is not controlled by blocking
filtration even in the initial filtration period.It corresponds to
the resistance distribution.In dead-end filtration of sludge,the
relative flux is in the tendency to the exponential decay along with
f iltration time and achieves the relative stability index in a few
minutes. Furthe rmore,the low pressure is in correspondence with the
higher flux,however,there is no correlation between decay index of
flux and pressure;the compressibility index of sludge is
0.7015.
Keywords:SMSBR; coke wastewater; mechanism of
membrane fouling; dead-end filtration
1 膜污染的表征
膜污染是用膜过滤过程中的污染阻力来表征的。根据达西(Darcy‘s law)方程：
J=ΔP／μR (1)
式中 J——膜通量，m/s
μ——透过液粘度，Pa·s
R——过滤总阻力，m-1
ΔP——膜两侧压差，Pa
在实际研究中由于所选用的膜和所过滤的料液特征不同，以及为了建立相应的模型，不同的研究者对膜污染阻力也有不同的理解［1～4］，归纳如下：
①
对于膜不完全截留
R=(Rm+Rp+Rf=Rm+Rp+Ref+Rif=Rm+Rc+Rif (2)
②
对于膜完全截留
R=Rm+Rp+Ref=Rm+Rc (3)
③
根据水力清洗
R=Rm+Rf=Rm+Rrf+Rirf (4)
式中 Rm——清洁膜固有的阻力
Rp——凝胶极化阻力
Rf——污染阻力，为Ref与Rif之和
Ref——外部污染阻力
Rif——内部污染阻力
Rc——沉积阻力，为Rp与Ref之和
Rrf——可逆污染阻力(包括极化层阻力)，能通过水力清洗消除
Rirf——(不可逆污染阻力，不能通过水力清洗消除
|
教育论文中心