The Clean Water Act of 1972 limited the amount of Phosphates allowed in detergents
Nitrogen and Phosphorus Pollution in Limnological Systems
Nitrogen and PhosphorusPoint Source Vs. Non Point Source PollutionMarek Koloszyc & Stacey Findlater
Point Source Pollution• Point-source pollution occurs when pollutants enter a waterway directly.• Can be tracked back to a specific source , location and offender.• Easier to regulate and manage compared to Non- Point Source pollution.
Major Sources of Point Source PollutionSewage Treatment Plant Effluent• Excess nutrients – nitrogen and phosphorus compounds• Detergents and personal care products • as an additive phosphorus softens water and loosens dirt particles from fabricsIndustrial Effluent • Manufacturing and mining end of pipe pollutionAquaculture Fish Farms • large numbers of fish in a small area
Possible Technological Enhancements:• Activated carbon filters-to remove phosphorus and nitrogen• Ion exchange filters –remove charged ions• Enhanced nutrient removal (ENR) with can reduce total nitrogen down to 3 mg/L or less and total phosphorus to 0.3 mg/L or less• Effluent filtration in combination with chemical precipitation can be used to remove phosphorous to very low levels (< 0.1 mg/L)
Aquaculture – Fish Farms• A Special case of agricultural pollution• Rapidly growing industry in both fresh and marine water• Feed wastes (up to 20%) and fish wastes - contribute to nutrient loading and eutrophication• For every ton of fish, aquaculture operations produce up to 66 kilograms of nitrogen waste and between up to 10.5 kilograms of phosphorus waste• Greatly impacts Benthic communities and native fish Georgian Bay rainbow trout Farm
Issues Caused by Excess Nutrients in water Bodies•Increase in production and biomass ofalgea•Massive fish kills – due to deoxygenation•Drinking water odour and taste problemsduring algal blooms•Piles of rotting algae along shore line•Recreation ,navigation and irrigation areaffected•Harmful algal blooms – production of toxins, acutely toxic or cause skin rashes, poisonshellfish•Dead zones•Loss of desirable fish ( salmon and trout)•Economic loss
Methods to Control Excess Nutrient InputUse advanced ( tertiary)waste treatment to removenitrates and phosphatesfrom effluentlimits on phosphates inhousehold detergents andother cleaning agentsSoil conservation and land-use control to reducenutrient runoff But Can more be done?
Trophic Classification of Aquatic Ecosystems • Oligotrophic – Low levels of organic matter – tend to be deep and clear , oxygen rich bottom supports cold water fish such as trout , Phosphorus is limiting • Mesotrophic – more organic matter, oxygen level in lake bottom is low • Eutrophic- High levels of organic matter – abundant plant growth , poor clarity , stratified with oxygen poor bottoms • A dead zone is an area where oxygen levels fall below 2 ppm
The Nitrogen Cycle• The most common forms of nitrogen in wastewater are: Ammonia (NH3) Ammonium ion (NH4+) Nitrite (NO2‐)Nitrate (NO3‐) and Organic nitrogen• Microorganisms make all chemical forms of nitrogen interchangeable• Organic forms of nitrogen are broken down and converted to ammonium in a process called ammonification• Nitrate and Ammonium are used by primary producers• Ammonia is oxidized to nitrate by nitrifying bacteria in aerobic zones and the nitrate is converted to free nitrogen in the anoxic zone by denitrifying bacteria – removing it from the environment
The Phosphorus Cycle• One of the Slowest nutrient cycles• Phosphorus is limiting in Marine systems – natural phosphorus comes from the weathering of rocks• Anthropogenic sources are rapidly taken up by primary producers – resulting in rapid overproduction• Phosphates in marine ecosystems precipitate out as iron phosphate and form a sink in the sediment
Marek this is a good place for you tostart maybe ?
Some Types of Algal Blooms Green Algae• Cladophora sericea - filamentous ,covers rocky areas and shorelines , can carry pathogens Blue –Green Algae (cyanobacteria)• Microcystis aeruginosa colonial , float on water surface – blooms is warm fresh nutrient enriched water – produces the toxin microcystin – kills dogs ,fish and shellfish, toxic or harmful to humans• Aphanizomenon flos-aquae – can produce endotoxins that are released when the algae dies• Ananaena sp. – filamentous , fix nitrogen , can produce neurotoxins
Lake Erie 1960 – 2011 Case study• 1960’s – Scientists recognize that Lake Erie was suffering from eutrophication – and it was caused by human activities • Algal blooms covered large areas of the lake during summer months , decomposing algae on bathing beaches was removed by bulldozers • “Newspaper headlines announce Lake Erie is Dead”• 1972 The Great Lakes Water Quality Agreement led to a coordinated effort to reduce phosphorus – a 60% reduction in loading to lake Erie • Algal blooms of Aphanisomenon reported as decreasing in intensity and number• 1980’s – Arrival of Zebra Muscles - several years of improved water clarity – species changes• 1990’s – large summer blooms of Microcystis reappear• 2003-2006- Algal blooms each summer of Microcystis Lake Erie Oct 5 2011 The Big Question - Why is eutrophication of Lake Erie Microcystis Areuginosa continuing to get worse since the 1972 Agreement?
Restoration of Eutrophic Lakes• Chemical treatments – Copper sulfate , calcium hydroxide or calcium carbonate (lime) – reduces chlorophyll a levels in water but may be toxic to non target organisms• Oxygenation – oxygen helps fish survive warm months and reduces algae• Dredging – effective but expensiveRestored wetlands in watershedsRiparian Buffer Strips along streams and estuaries
Restoration of Eutrophic Lakes ‐ Setbacks• Eutrophic lakes tend to be shallow and suffer from nutrient loadings from point / non point source pollution• Lake sediments are polluted with nutrient enriched soil particles from shore erosion• Phosphorus enriched particles sink to the bottom and form a pool of nutrients for rooted plants – internal load
Riparian Buffer Strips A well defined Riparian Buffer along a lake Erie tributary• May be Natural or engineered for restoration• Represent both wetland and forest habitats for wildlife• Herbaceous , shrubby plants and trees with strong roots• Prevent Nutrients and Sediment from entering watershed• Useful in intensively used agricultural areas with channeled water
Nitrogen and Phosphorus removal in Wetlands• Wetlands act as a sponge , plants take up some nutrients• Phosphorus complexes to soil• Nitrogen is most effectively removed by denitrification• Restored wetlands provide habitat for wildlife and attract hundreds of birds• Provide a space for naturalists and birdwatchers St. Clair River Restoration
Mineral Fertilizers – Possible Solutions• Fertilizer Plans for land owners – soil testing and active planning• Increased autumn/winter green cover – to reduce leaching of nutrients from bare soil• Subsidize smart application methods• Develop new environmentally sound fertilizers• Tax mineral fertilizers , and lawn fertilizers containing phosphate• Funding for Wetland restoration and Riparian strips
Success And On To The Next!• In the 1970’s detergents contained 40% phosphorus by weight• The Great Lakes Water Quality Agreement in 1972 banned phosphates in laundry detergents• July 1, 2010 New federal regulations on dishwasher detergents and household cleaners ban phosphates (0.5%) by weight• This is expected to reduce anthropogenic phosphorus loads by 10%• This should be considered a success as we move on to the next set of Issues
Phosphate Free Detergents Receive Bad Press• News- National Post – “Phosphate Bans Means Streaky Dishes” – Jan 6,2011• Complaints about dishwasher detergents on online blogs – short sighted and selfish• Public needs to be educated to think greener!• Tip! – white vinegar or lemon juice can be used in dishwashers as a natural rinse agent
Gostou de algum slide específico?
Recortar slides é uma maneira fácil de colecionar informações para acessar mais tarde.