Comparison of Catalysts Used to Determine COD_(Cr) of Severe Domestic Sewage

[Objective] The study aimed to find the best catalyst for the determination of CODc, of severe domestic sewage. [ Method] Adopting po- tassium dichromate reflux method, respectively using MnSO4, Ag2 SO4 ·MgSO4, CuSO4, KAI （ SO4 ） 2, CuSO4 ·KAI （ SO4 ） 2 · （ NH4 ） 2 MoO4 and Ag2 SO4 .Al2 （SO4）3· MgSO4 as catalysts, we determined CODo of severe domestic sewage, and compared their results with that of Ag2 SO4. [ Result] Used as catalysts in the determination of CODc, of severe domestic sewage, MnSO4, Ag2SO4. MgSO4, CuSO4, KAI （SO4）2, CuSO4· KAI （ SO4 ） 2 · （ NH4 ） 2 MoO4 and Ag· SO4- AI2 （ SO4 ） 3· MgSO4 had good catalytic effects, especially Ag2 SO4- AI2 （ SO4 ） 3·MgSO4. Average CODcr of Ag2 SO4·Al2 （SO4）3·MgSO4 and Ag2 SO4 was 229.32 and 254.28 mg/L separately, that is, the former accounted for 90.18% of the latter, so the result of Ag2SO4 could reflect the actual CODc, of severe domestic sewage better. [ Conclusion] Ag2SO4 is the optimal catalyst for the determination of CODc, of severe domestic sewage.