Nature of ecosystems Energy flow – microbes are decomposers Water Carbon Nitrogen

Nitrogen Fixing Bacteria Nitrifying Bacteria N2 to NH3 Cyanobacteria Methylotrophic bacteria Rhizobium – symbiotic

Water Pollution Chemical Biological Indicator organism – E. coli

Coliform Tests Membrane Test MUG (ONPG) Test Water is filtered ______________ is placed on agar Colonies are counted MUG (ONPG) Test Fluorescence (yellow color) indicates E. coli presence

Sewage Treatment Sewage – used water Primary Solids separated from liquid Floating ____________ is shredded Skimmers remove ___________________ ___________________ recovered Organic solids (__________) removed

Secondary Sewage treatment Activated sludge treatment Air is pumped into liquid in a tank Microbes are added as a sludge and decompose organic material Trickling filtration Sewage aerated by spraying Moves over a layer of aerobic microbes on rocks 80% removal of organic matter (BOD)

Tertiary Sewage Treatment Filters can remove the last 5-20% of organics Costly process Applications: