procurement of closed cod digester and cod vials for laboratories under cwa ( w&s ) -ii division.-- 1 closed reflux cod ssytem( make : wtw/thermo-fisher scientific,/lovibond/ hach/antylia )scope of supply : cod photometer, cod digester with 24 samples digestion assembly at a time, test tube stand and vials (15-300 mg/ltr oxygen and 20-1500 mg/ltr. oxygen)method : analogous to iso 15705:2002measurement principle : photometry closed reflux systemcod digester specification:construction materials : housing: abs , protection grid: pps , lid: pc , block insert: pbt , heating block: aluminium holes in the aluminum block : 24 holes, ø 16.2 mm ± 0.2 mmselectable temperatures : 100 / 120 /150 °cprobe type : pt 100 a classtemperature stability at pt 100 : ± 1 °cselected time : 30 / 60 / 120 / continuous (8) minheating up from : (20 °c --> 150 °c) 12 minthermoregulation : microprocessorprotection against overheating : at the auto block for 190 °cphotometerspecification:instrument : double wavelength, automatic wavelength selection, direct reading colorimeterlight source: : leds, interference filters (if) and photo sensor in transparent cell chamber. wavelength specifications of the if: 430 nm ?? = 5 nm, 610 nm ?? = 6 nmwavelength accuracy : ± 1 nmphotometric accuracy : 3% fs (t = 20° c – 25° c)photometric resolution : 0.01 apower supply : 4 batteries (aa/lr6) operating time : 17hr operating time or 5000 measurements in constant use when display backlight and bluetooth® data transfer are offauto-off : automatic switch off 10 minutes after last key pressinterface : bluetooth® 4.0 for the transfer of stored measurement datatime : real time clock und datecalibration : user and factory calibration , resetting to factory calibration possibleambient conditions : temperature: 5 – 40 °c , rel. humidity: 30– 90 % (non-condensing)portability : bench top.certification : the manufacturer should have iso certification for manufacturing water testing instruments and reagents 2 vials ranges and methods : low range: 3 - 150 mg/l, meets iso 15705:2002(500 vials) middle range: 20 - 1500 mg/l, meets iso 15705:2002 (3200 vials)