240 likes | 349 Views
CE3503 Environmental Engineering. Energy Flow in Ecosystems (Section 5.3) Representation by Effect (Section 2.5.4) Biochemical Oxygen Demand (Section 5.4). Energy Flow in Ecosystems. Energy Flow in Ecosystems. Energy fixation Organic matter Autotrophs Heterotrophs Aerobic respiration.
E N D
CE3503 Environmental Engineering Energy Flow in Ecosystems (Section 5.3) Representation by Effect (Section 2.5.4) Biochemical Oxygen Demand (Section 5.4)
Energy Flow in Ecosystems Energy fixation Organic matter Autotrophs Heterotrophs Aerobic respiration
Energy Flow in Ecosystems Anaerobic respiration Mercury cycling Nitrate removal Drinking water Sludge digestion
Energy Flow in Ecosystems Biomass Production Autotrophs Primary producers Algae Phytoplankton Heterotrophs Secondary producers Primary Consumers Herbivores Zooplankton Heterotrophs Secondary consumers Planktivores Heterotrophs Tertiary consumers Piscivores Carnivores (also omnivores)
Energy Flow in Ecosystems Food chain Food web
Microbial loop (sustainable?) Energy Flow in Ecosystems
Organic Matter. … what’s in here?
Carbohydrates (sugar and the polymers starch and cellulose) Proteins (polymers of amino acids) Fats (formed from glycerol and fatty acids) Organic Matter. Fats (
Organic Matter. Photosynthesis Respiration also …mineralization oxidation stabilization
Representation by Effect - Organic Matter. Respiration When organic matter is used as a substrate for respiration, … when it is oxidized … when it is mineralized … when it is stabilized it exerts a “biochemical oxygen demand” or BOD.
BOD - Representation by Effect. … impacts on lakes and rivers?
Biochemical Oxygen Demand BOD: the amount of dissolved oxygen (mg/L) required to oxidize the organic matter in water. CBOD: BOD exerted through oxidation of carbonaceous material. NBOD: BOD exerted through oxidation of ammonia.
Biochemical Oxygen Demand NBOD is simple stoichiometry, Stoichiometry does not work for CBOD because not all of the organic matter present is biodegradable. Thus the CBOD is never greater and almost always less than the theoretical BOD (ThBOD). but for wastewater, not so much!
Biochemical Oxygen Demand BOD Remaining (L) BOD Exerted (y)
Biochemical Oxygen Demand BOD Exerted BOD Remaining
Biochemical Oxygen Demand 5-day BOD and Ultimate BOD 5-day BOD is a laboratory measurement. Ultimate BOD is for field aplications.