Chapter 22 Water Pollution and Treatment Biochemical Oxygen

Chapter 22 Water Pollution and Treatment

Biochemical Oxygen Demand • The amount of oxygen required for biochemical decomposition process. • 3 zones A pollution zone An active decomposition zone A recovery zone • When BOD levels are high, DO is low

This diagram shows the relationship between DO and BOD.

Waterborne Disease • Outbreaks of waterborne diseases – Milwaukee, WI - Cryptosporidium – Fecal Coliform Bacteria – Walkerton, ON – E. coli

Nutrients • Eutrophication – The process by which a body of water develops a high concentration of nutrients • Cultural Eutrophication – When eutrophication is accelerated by human processes that add nutrients to a body of water

Acid Mine Drainage • Water with a high concentration of sulfuric acid that drains from mines • Serious water pollution problem • Damages aquatic ecosystems, pollutes bodies of water and degrades water quality

Surface Water Pollution • Water Pollutants are emitted from – Point Sources • Distinct and confined sources such as pipes from industrial or sites – Nonpoint Sources • Diffused and intermittent • Ex) runoffs from streets

Groundwater Pollution • Bioremediation: – a method of treating groundwater pollution problems that utilizes microorganisms in the ground to consume or break down pollutants

Wastewater Treatment • Septic Tank Disposal Systems • Waste Treatment Plants – Primary Treatment – Secondary Treatment – Advanced Treatment – Chlorine Treatment

Wastewater Renovation and Conservation Cycle • Steps: – 1. Return of treated wastewater to crops – 2. Renovation or natural purification by slow percolation of the wastewater into soil to eventually recharge the groundwater resource with clean water – 3. Reuse of the treated water

Water Reuse Inadvertent: – water is withdrawn, treated and returned to the environment Indirect: – Ex) the wastewater renovation and conservation cycle Direct: – The use of treated wastewater that is piped directly from a treatment plant to the next user

Water Pollution and Environmental Law • Environmental Law – The branch of law dealing with conservation and use of natural resources and control of pollution • Clean Water Act - 1972