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CE 3231 - Introduction to Environmental Engineering and Science. Readings for This Class: 5.5 -5.6. O hio N orthern U niversity. Chemistry, Microbiology & Material Balance. Introduction. Water & Air Pollution. Env Risk Management. Biological Oxygen Demand
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CE 3231 - Introduction to Environmental Engineering and Science Readings for This Class: 5.5-5.6 Ohio Northern University Chemistry, Microbiology & Material Balance Introduction Water & Air Pollution Env Risk Management Biological Oxygen Demand When microbes and organic carbon are plentiful in lakes and streams, the microbes take over. The result is an oxygen depleted system that is very microbially diverse, but is void of higher trophic level organisms. Understand BOD and changes in OD is critical to maintaining healthy water quality.
Lecture 24BOD Exertion and BOD levels downstream(Water Quality IV)
Measures of Water Quality • Dissolved Oxygen (DO) and Oxygen Demand (OD) • Total Dissolved Solids (TDS) • Nutrients • Metals • Pathogens • Organic compounds – Total organic compounds (TOC)
Oxygen Demand • Measure of amount of oxygen demanding organic and inorganic matter in a water • Measurement • ThOD– • COD – • BOD –
Theoretical Oxygen Demand (ThOD) • The total amount of oxygen required to: • Calculated using stoichiometric principles • Calculate ThOD for 1 g/L of glucose
Biochemical Oxygen Demand (BOD) • BOD = DOinitial – DOfinal • BOD = Lo – Lt • L = oxygen consumed • Lo = initial • Lt = @ time = t
Biochemical Oxygen Demand (BOD) • BOD Definition: • BOD is used: • Slow analysis: • Typical analysis: • Dependent upon:
Simple Plug Flow River Model Objective: derive a mathematical model to predict DO downstream: DO(x,t) - take your shot at it! Wastewater discharge (High BOD, Low DO) • Assumptions: • completely and uniformly mixed in the cross flow and vertical direction • neglect pollutant dispersion