Hanna Instruments HI 98186 Instruction Manual

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Hanna Instruments HI 98186 Instruction Manual Manual pdf 24 page image

24S O U R M E A S U R E M E N TS O U R M E A S U R E M E N TS O U R M E A S U R E M E N TS O U R M E A S U R E M E N TS O U R M E A S U R E M E N TThe Specific Oxygen Uptake Rate (SOUR), also known as the oxygen con-sumption or respiration rate, is defined as the milligram of oxygen consumedper gram of volatile suspended solids (VSS) per hour. This quick test hasmany advantages: rapid measure of influent organic load and biodegrad-ability, indication of the presence of toxic or inhibitory wastes, degree ofstability and condition of a sample, and calculation of oxygen demand ratesat various points in the aeration basin.The following equation is used for SOUR determination:SOUR = OUR / Solids Weightwhere:OUR is the Oxygen Uptake Rate (see equation on pag 20)Solids Weight is theTotal solids or theVolatile suspended solids weight ing/LTemperature correction:The SOUR value is corrected to 20 °C (68 °F) according to the Farreland Bhide equation:SOUR20=SOUR TxQ (20-T)Where T is the measured temperature in °C and Q is a temperaturedependent variable:Q = 1.05 for T above 20 °CQ = 1.07 for T below 20 °CThis calculation is valid only for temperature values in the range 10 to 30 °C.Temperature correction is performed only if the option SOUR @20°C isenabled from SOUR configuration in the setup menu.Before starting a SOUR test remember to set the SOUR configuration fromthe setup menu.SOUR measure screen:If the SOUR value is corrected to 20 °C (68 °F) the message “@20°C”, or”@68°F” according to the currently selected temperature unit, will bedisplayed above the measured temperature.Press Start to begin a new SOUR test.