Presentation on theme: "Do Now: Where does our water go when we flush the toilet? Wash our hands in the sink? Water our lawns, wash our cars?"— Presentation transcript:
1 Do Now:Where does our water go when we flush the toilet? Wash our hands in the sink? Water our lawns, wash our cars?
2 Aim: How Can We Best Deal with Water Pollution? Concept Reducing water pollution requires we prevent it, work with nature to treat sewage, cut resource use and waste, reduce poverty, and slow population growth.
3 Reducing Surface Water Pollution from Nonpoint Sources AgricultureReduce erosionReduce the amount of fertilizersPlant buffer zones of vegetationUse organic farming techniquesUse pesticides prudentlyControl runoffTougher pollution regulations for livestock operationsDeal better with animal waste
4 Pause…Think…Write…Should we greatly increase efforts to reduce water pollution from non point sources even though this could be quite costly?
5 Laws Can Help Reduce Water Pollution from Point Sources 1972: Clean Water Act : sets limits for 100 water pollutants and requires polluters to get permits that limit how much they can discharge.1987: Water Quality Act: strengthened the federal water quality regulations by providing changes in permitting and adds substantial penalties for permit violations.
6 Laws Can Help Reduce Water Pollution from Point Sources EPA: experimenting with a discharge trading policy that uses market forcesCap and trade systemCould this allow pollutants to build up? Lower the cap!
7 Do you understand how laws can be both good and bad?
8 Case Study: The U.S. Experience with Reducing Point-Source Pollution Numerous improvements in water qualitySome lakes and streams are not safe for swimming or fishing -40%Treated wastewater still produces algal bloomsHigh levels of Hg, pesticides, and other toxic materials in fish
9 Case Study: The U.S. Experience with Reducing Point-Source Pollution Leakage of gasoline storage tanks into groundwaterMany violations of federal laws and regulations (unclear which water ways are covered under CWA)Need to strengthen the Clean Water Act: fines are cheap!
11 Waste water treatment from flush to finish movie What happens during the primary, secondary, and tertiary treatment of waste water?
12 Solutions: Primary and Secondary Sewage Treatment
13 We Can Improve Conventional Sewage Treatment Peter Montague: environmental scientistRemove toxic wastes before water goes to the municipal sewage treatment plantsReduce or eliminate use and waste of toxic chemicalsUse composting toilet systemsWetland-based sewage treatment systems
14 Science Focus: Treating Sewage by Working with Nature John Todd: biologistNatural water purification systemSewer water flows into a passive greenhouseSolar energy and natural processes remove and recycle nutrientsDiversity of organisms used
15 Solutions: Ecological Wastewater Purification by a Living Machine, RI, U.S.
16 There Are Sustainable Ways to Reduce and Prevent Water Pollution Developed countriesBottom-up political pressure to pass lawsDeveloping countriesLittle has been done to reduce water pollutionChina : ambitious plan