Water Testing APES

Lab Investigations for APES

Know the basis for each test and what the test measures.

Dissolved Oxygen (DO) BOD (Biological Oxygen Demand) Total hardness pH and total alkalinity Nitrate / nitrite nitrogen Turbidity (Total Suspended Solids) Fecal Coliforms

Dissolved Oxygen (DO) Atmosphere = 200 mL/L Water = 5-10 mL/L Temperature is a factor Cold water can hold more DO Salinity is a factor Fresh water has higher DO than salt water Elevation is a factor Water at higher elevations contains less DO due to air pressure Aeration = Churning/disturbing the water adds DO

DO Nomogram Water temp of 10 C and 9ppm Oxygen = 80% saturation

FYI: ppm = mg/L http://www.lakeaccess.org/russ/oxygen.htm

BOD (Biological Oxygen Demand) Aerobic microorganisms (including bacteria) decompose organic matter in a water source. As they do, they use up a lot of the oxygen in the water, thus creating an oxygen sag. High BOD indicates lots of organic matter that will put a strain on oxygen supplies.

The plant we visited influent = 274 mg/L effluent = <2.0 mg/L

Water Hardness (Total Dissolved Solids, TDS) Measure of the amount of DISSOLVED solutes in the water, typically salts, metals, cations, anions, (Calcium and Magnesium are common) http://www.tdsmeter.com/what-is?id=0004

pH and total alkalinity Total alkalinity is the total concentration of bases in water expressed as parts per million (ppm) or milligrams per liter (mg/L) of calcium carbonate (CaCO3). Ideal pH is around 7 or slightly higher Aquatic life is sensitive to acids or strong bases

Nitrates/Nitrites Once again, measured in mg/L Nitrates (and phosphates) are limiting factors of aquatic organisms. Excessive Nitrates cause blooms. The decomposition of the dead blooms consumes most of the oxygen creating a dead zone (EUTROPHICATION)

Turbidity (Total Suspended Solids, TSS) Measure of the amount of particles suspended in the water. Do not settle or dissolve. “Murkiness” mg/L - higher the number, more murky Decreases amount of light penetrating the water for photosynthesis Particles can absorb heat, increasing temperature, lowering DO

Turbidity Removal In general, surface water will need pre-treatment to reduce turbidity before it is disinfected (Wisner, 2002). Treatment methods which reduce turbidity include sedimentation, roughing filters, rapid and slow sand filters, chemical coagulation and flocculation, and ceramic filters. http://www.youtube.com/watch?v=-DUTX7G7wlU

Fecal Coliforms Measure of the amount of fecal coliforms per 100mL Organisms / 100mL Not necessarily harmful, but high levels indicate a failure of waste water treatment or contamination from animal waste Increased risk of water-borne illness

Turbidity Removal In general, surface water will need pre-treatment to reduce turbidity before it is disinfected (Wisner, 2002). Treatment methods which reduce turbidity include sedimentation, roughing filters, rapid and slow sand filters, chemical coagulation and flocculation, and ceramic filters. http://www.youtube.com/watch?v=-DUTX7G7wlU

Secchi disk