废水COD 4种物化表征方法的比较与评估

为了确定废水COD组分表征的物化分析方法,对0.1μm滤膜过滤、0.45μm滤膜过滤、絮凝和絮凝+0.45μm滤膜过滤4种方法进行了实验比较和评估。结果表明:某些材料的滤膜会因"COD溶出"而影响表征结果;4种方法分离废水的重现性都很好,相互没有明显区别;物化分离对废水快速可生物降解COD(SS)没有影响,但4种方法得到的处理液中可生物降解COD仍含降解速率明显不同的组分,其中SS仅占35%～45%。因此,物化方法不能合理表征SS;絮凝+0.45μm滤膜过滤速度快、干扰少、分离机理与活性污泥系统类似,更适用于废水溶解性惰性COD组分(SI)表征。

Comparison and evaluation of four physical-chemical methods for wastewater COD characterization

In order to determine a suitable physical-chemical method for wastewater COD characterization,four methods of flocculation,flocculation+0.45 μm membrane and direct filtration using 0.1 μm membrane and 0.45 μm membrane were compared and evaluated experimentally.The results showed that some kinds of membrane could affect the measurements due to significant "COD release".The reproducibility of the four methods filtrating wastewater is satisfied and comparable.The treatment of physical-chemical separation has no effects on the analysis of readily biodegradable COD fraction(SS).However,the biodegradable COD(BCOD) in their filtrates contains COD fractions with different biodegradation rates,in which the percentage of SS is only 35%～45%.It is concluded that physical-chemical methods could not characterize SS appropriately.In terms of the soluble inert COD(SI),flocculation+0.45 μm membrane could be more advantageous because of its speediness,less interference and similar separation mechanism to activated sludge system.