Akademik Veri Yönetim Sistemi
2ND INTERNATIONAL CAPPADOCIA SCIENTIFIC RESEARCH CONGRESS, Nevşehir, Türkiye, 17 - 19 Haziran 2022, ss.723-731
Slaughterhouse wastewater treatment by advanced oxidation processes (AOP) is encouraged
to increase the overall quality and reusability of the discharge water. And several AOPs such
as Fenton oxidation, UV radiation, ozone, and photocatalytic oxidation involves the use of
hydrogen peroxide (H2O2) for the production or intensification of hydroxyl radicals (OH●
). In
some cases, a quick measurement of H2O2 is required to track the concentration of residual
H2O2 in a sample, for optimization and evaluation of the performance of the applied AOPs. In
this study, two commonly used spectrophotometric residual H2O2 measurement options,
potassium titanium (IV) oxalate (PTO) and iodometric-colorimetric (I3
-
method by Klassen
1994) were compared for a slaughterhouse wastewater matrix. Slaughterhouse wastewater
was prepared in the laboratory by mixing a known amount of blood with tap water. The
pH of all samples was adjusted to 3.00, and 50 mg/L H2O2 was added. Reaction time, organic
matter concentration, and dilution factor (DF) were used for the comparative analysis of the two
methods. In the PTO method, color development is instantaneous and stable while the I3
method required ~5 minutes of reaction time. Both methods were stable and unaffected by
organic matter concentration. Cod of 2000 to 100 mg/L were used for organic matter
presence evaluation. PTO method residual H2O2 recovery was between 95-98% and recovery
by I3 method was between 104-110%. Slaughterhouse wastewater is highly colored and can
include turbidity which is a problem for spectrophotometric measurements. Such samples
usually demand pre-processing like dilution or filtration before measurement. Increasing the
dilution factor decreases the color intensity and background color interference in the sample.
The PTO method can directly measure the residual H2O2 with 102-105% recovery in DF1 (no
dilution) to DF5. On the other hand, the I3 method required at least DF 50 for direct
measurement. A sample blank can be used in both methods to minimize color interference.
When sample blank was used in the I3 method for DF50 to DF2, 103-105% recovery was
achieved but for DF1, recovery was only 80%. The use of sample blanks in an ongoing
experiment can be time-consuming along with necessary dilutions to meet the calibration
range of the method (10 mg/L for I3 and 100 mg/L for PTO). PTO method with rapid color
change, higher measurement concentration range was able to measure residual H2O2 within 2
minutes. So, a practical method (PTO) with high precision is preferable.