Nitrogen and Phosphorus Point Source Vs. Non Point Source

Pollution

Marek 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 Pollution

Sewage 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 fabrics

Industrial Effluent • Manufacturing and mining end of pipe

pollution

Aquaculture 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 of algea•Massive fish kills – due to deoxygenation •Drinking water odour and taste problems during algal blooms•Piles of rotting algae along shore line•Recreation ,navigation and irrigation are affected•Harmful algal blooms – production of toxins , acutely toxic or cause skin rashes, poison shellfish •Dead zones•Loss of desirable fish ( salmon and trout) •Economic loss

Methods to Control Excess Nutrient Input

Use advanced ( tertiary) waste treatment to remove nitrates and phosphates from effluentlimits on phosphates in household detergents and other cleaning agentsSoil conservation and land-use control to reduce nutrient 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 to start 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

The Big Question - Why is eutrophication of Lake Erie continuing to get worse since the 1972 Agreement?

Lake Erie Oct 5 2011Microcystis Areuginosa

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

• 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

A well defined Riparian Buffer along a lake Erie tributary

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