Testing for Chemical Oxygen Demand (C.O.D.)
*** The wastewater section is under construction! ***
Wastewater samples are generally collected as composites. Samples collected by NEL receive 2.5 mL 1+1 nitric acid per 250 mL. Additional 2.5 mL aliquots may be added and noted on C-O-C as necessary to ensure pH <2. Digestion is mandatory and filtration or centrifugation are sometimes necessary.
Drinking water samples are generally collected as grabs.
Samples collected by customers such as homeowners are preserved upon receipt at the laboratory with 5 mL conc. nitric acid (Trace Metal Grade) per liter.
Samples collected by NEL receive 2.5 mL 1+1 nitric acid per 250 mL .
Plastic containers supplied by NEL are rinsed with 1+1 nitric acid, 1+1 hydrochloric acid and triple rinsed with deionized water.
|O&G, CN, ABN, PCB/Pest.||1 liter glass / teflon-lined caps||Supplied by Subcontractor|
|BOD TSS TDS||1 liter plastic||Detergent wash and 3X DI rinse|
|Metals||0.1 – 1.0 liter plastic||Acid washed and 3X DI rinse|
|VOA/VOC||40ml VOA vials / teflon-lined caps||Supplied by Subcontractor|