1 Water POllution
2 BOD: What is it? Biodegradable organic matterExcess is consumed by bacteria in the water They deplete the water of oxygen Example: Gold fish bowl
3 What causes a buildup of BODFall leaves Animal/human waste discharge Process plant discharge-especially in food manufacturing
4 Conditions that can cause elevated levelsWater temperature increases causing the bacterial population to increase If sufficient organic material is present in the water
5 How can you measure it Chemists mix water with “organics” with oxygen and test how long it takes for the oxygen levels to drop This test is typically 5 days at a lab COD testing is another route Much more cost effective Quicker results Can be done in house
6 March 2016: Florida Fish KIll
7 What is El Nino? Climate cycle begins in the Pacific OceanWarm water from the western tropical Pacific ocean shifts eastward along the equator of South America Forcastors declare an official El Nino when they see both ocean temperature and rainfall veer towards the east Happens every 3-5 years
8 El nino Super El Nino Hottest summer yet ( warmest summers) Sea surface temperatures peak around December, impact is usually seen a few months later as the global ocean heats up 2015 hottest year ever without El Nino, but El Nino caused a 8-10% increase in temps as well
9 El Nino Causing massive algae bloomPseudo-nitzschia genus produces a deadly neurotoxin Builds up in sediment and sea-life Warm water in the Pacific (The Blob) combined with nutrient rich water of Pacific coast=perfect conditions Duration of algae blood precedented
10 Algae Bloom COmplicationsFish kills Amnesic shellfish poisoning GI issues Vomiting and diarrhea after ingestion Must be monitored and communicated in the summer during blooms Dungeness crab/clamming
11 Hormone Disruptors and DrugsPulp mills release estrogen-like compounds in significant amounts into lakes and rivers Changes the hormonal system of the animals that ingest them When fish are exposed to these hormones, male fish develop both male and female reproductive parts Female birth control pills
12 Hormone Disruptors and DrugsPaper mills release group of potentially harmful materials know as dioxins High levels are carcinogenic Low levels will suppress the immune systems of animals/humans Some have converted to chlorine free processes, but very little have converted thus far
13 Sewage Treatment and DisposalPrimary sewage treatment Secondary sewage treatment Tertiary treatment
14 Primary Sewage TreatmentSettling tanks (Clarifiers) Removes solids from water/fluid chlorinated and discharged Travel through screens when it enters the plant Sludge is pumped to the digester Bacteria feed on it Methane gas is produced-can be burned off Primary treatment removes 30-60% BOD
15 Secondary Treatment Aerobic bacteria to break down degradable organic materials Removes ammonia to nitrates Activated Sludge Process Trickling Filter
16 Activated Sludge ProcessFluid is pumped out of the clarifier into another tank that is aerated Aerobic bacteria breakdown BOD drops rapidly due to increase oxygen and aerobic bacteria Then transferred to settling tank Remaining suspended material and bacteria sink to the bottom
17 Sludge digester Sludge is transferred to the anaerobic digesterIt is broken down to activated sludge due to the lack of oxygen Some is recycled back to aeration tank to seed the tank What is left is dried and can be used as a fertilizer or go to the landfill
18 Trickling Filter Sewage is sprayed by arms that are slowly rotating onto a filter bed of stones Stones are covered with thin film to help dissolve organic compounds Solids are transferred to sludge tank 80-85% of dissolved organics are removed
19 Tertiary Treatment Removes nitrates and phosphatesNot all waste water systems have tertiary treatments Four times as expensive to operate Currently 50% of treatment plants have tertiary treatment
20 Recycling Waste Fuel Livestock feed Soil fertilizerBiogas used to run sewage Livestock feed Proteins and fats that are required Soil fertilizer Land apply