Management of Non-Point Source Pollution CE 296B

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Management of Non-Point Source PollutionCE 296B

• Department of Civil Engineering
• California State University, Sacramento

Lecture 7, February 19, 1998 Sources of
Pollutants - Part III
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Recall that we were looking at the six categories
of pollutants
1. Toxic inorganics - e.g. metals 2. Synthetic
organics - e.g. solvents 3. Biostimulants - BOD,
nutrients 4. Sediment - clay, silt, sand,
gravel 5. Pathogenic organisms - viruses,
bacteria, protozoa 6. Trash - use your imagination
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And the framework for acquiring knowledge about
each category
1. What are the sub-categories in each category
and what are representative members? 2. What are
the origins of pollutants? 3. How pollutants are
introduced to the flow stream? 4. How pollutants
behave in water?
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IV. The third category of pollutant to examine is
biostimulants.

• A. Define what a biostimulant is
• A biostimulant is a substance, that when added
  to a receiving water, allows primary members of
  the food chain to increase their metabolic
  activity.
• 1. Primary members of the food chain
• Bacteria
• Fungi
• Protozoa
• Algae

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IV. The third category of pollutant to examine is
biostimulants. (cont.) A. Define what a
biostimulant is (cont.) A biostimulant is a
substance that when added to a receiving water
allows primary members of the food chain to
increase their metabolic activity. (cont.)

• 2. Increase in metabolic activity means
• Microorganism reproduce faster, which in turn-
• Contributes to the process of eutrophication
• Leads to an increased rate of resource
  consumption such as dissolved oxygen

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IV. The third category of pollutant to examine is
biostimulants. (cont.) A. Define what a
biostimulant is (cont.) A biostimulant is a
substance that when added to a receiving water
allows primary members of the food chain to
increase their metabolic activity. (cont.)

• 3. To be living healthy receiving waters, some
  input of biostimulatory substances is required.
  The problem is when more than is required is
  added to a receiving water.

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IV. The third category of pollutant to examine is
biostimulants. (cont.)

• B. Categories of biostimulants
• Each category is based on an element that
  contributes to nutritional requirements.
• To survive, living organisms require a wide
  variety of elements. Most, such as copper,
  selenium, arsenic, are provided in excess in most
  receiving waters.
• The amount of three elements, carbon, nitrogen,
  and phosphorous typically control the amount of
  biological activity.

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.)

• 1. Carbon Defining element for organic
  compounds. The oxidation of organic compounds,
  increasing the oxidation number of the carbon
  atom, is the energy source for most organisms.

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.)

• Carbon metabolism can be either
• Aerobic
• Respiration - organic compounds are oxidized and
  oxygen serves as the terminal electron acceptor.
• Anaerobic
• Respiration - organic compounds are oxidized and
  an inorganic compound other than oxygen serves as
  the terminal electron acceptor.
• Fermentation - organic compounds are oxidized
  and organic compounds serves as terminal electron
  acceptor.

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 1. Carbon (cont.)

• a. Like virtually all other elements, carbon is
  cycled. Without a cycle, the worlds carbon would
  all end up in one form or another.

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Carbon Cycle
Oxygenic photosynthesis
Aerobic Respiration, Combustion of Organic
Material
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Oxidation of Organic Compounds
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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 1. Carbon (cont.)

• b. Measures of organic carbon in water samples
• BOD - The oxygen demand required to biologically
  oxidize the readily biodegradable carbon present.
• COD - The oxygen demand required to chemically
  oxidize virtually all the carbon present to CO2.
• TOC - The amount of organic carbon present,
  measured by pyrolosis.

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 1. Carbon (cont.)

• c. As noted, not all organic compounds are
  readily biodegradable. A good example is lignin,
  a common substance in all plant material. It
  degrades very slowly. What if we analyze a
  sample for BOD5 and COD look at the ratio

The closer this number is to one, the more
biodegradable the organic material in the sample
is.
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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 1. Carbon (cont.)

• d. Because it is a carrier for fallen leaves and
  twigs, non-point source run-off often has a

ratio of less than 0.2. BOD5 values are
typically less than 20 mg/L and COD values are
often above 80 mg/L. Substaintial concentrations
of volatile suspended solids (VSS) help confirm
the plant material connection.
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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 1. Carbon (cont.)

• e. Although carbon does have the potential to be
  a biostimulatory substance in non-point source
  run-off it is typically not considered a major
  problem.
• Note The plant material itself, as a mass
  loading effect, can certainly become a nuisance.

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Discussion Break

• As a biostimulatory substance, does organic
  carbon have a concentration pollution effect or a
  mass loading pollution effect?

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.)

• 2. Nitrogen For most organisms nitrogen is the
  second most required nutritional element, on a
  molar basis, after carbon. It is also the energy
  supply for nitrifying bacteria. These bacteria
  are present in all reasonable receiving waters.
• As with carbon, nitrogen has a cycle associated
  with it.

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Nitrogen Cycle
Ammonification (microorganisms)
Assimilation of nitrate
Nitrogen Fixation (microorganisms)
Assimilation of ammonia
Nitrate Reduction
Denitrification (microorganisms)
Nitrification (aerobic)
Nitrification (aerobic)
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Nitrogen Oxidation States
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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 2. Nitrogen (cont.)

• As can be seen from the nitrogen cycle, nitrogen
  in non-point source run-off can have a wide range
  of biostimulatory effects
• a. Assimilation of ammonia
• Assimilation of nitrate
• Can, if nitrogen is the rate limiting nutrient,
  stimulate the growth of primary members of the
  food chain.

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 2. Nitrogen (cont.) As
can be seen from the nitrogen cycle, nitrogen in
non-point source run-off can have a wide range of
biostimulatory effects

• b. Through the process of nitrification the
  growth of nitrifying bacteria is stimulated and
  more importantly oxygen is consumed.
• c. Through the process of ammonification the
  growth of microorganisms is stimulated.

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.) 2. As can be seen from
the nitrogen cycle, nitrogen in non-point source
run-off can have a wide range of biostimulatory
effects (cont.)

• d. Through the process of denitrification and
  nitrate reduction the growth of microorganisms is
  stimulated.

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Discussion Break

• The decay of plant material releases ammonia
  through the process of ammonification.
• How would a low BOD5 / COD ratio in a non-point
  source run-off lead to concern about mass loading
  problems with respect to nitrogen?

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IV. The third category of pollutant to examine is
biostimulants. (cont.) B. Categories of
biostimulants (cont.)

• 3. Phosphorous After carbon and nitrogen, the
  element next in line for the greatest requirement
  on a molar basis for balanced nutrition is
  phosphorous.
• Like carbon and nitrogen, phosphorous is cycled.
• Unlike carbon and nitrogen, no valence change
  takes place when phosphorous is cycled. Rather
  phosphorous is cycled between organic and
  inorganic forms.

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Phosphorous Compounds
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IV. The third category of pollutant to examine is
biostimulants. (cont.)

• C. What are the sources of biostimulants in
  non-point source run-off
• 1. Carbon Excess plant material such as grass
  clippings, fallen leaves, used Christmas trees,
  etc.
• 2. Nitrogen Excess plant material, fertilizers
• and, incomplete combustion.
• 3. Phosphorous Excess plant material, and
  fertilizers.

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Discussion Break

• The substantial imports of water from Northern
  California and Arizona to Southern California has
  allowed a far greater amount of plant material to
  grow in Southern California than would be
  possible under natural conditions.
• Could those water imports be considered
  biostimulatory non-point source pollution?
• How?

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Discussion Break

• How could perfectly immaculate application of
  fertilizer, i.e., no excess fertilizer run-off,
  yield biostimulant non-point source pollution
  with respect to
• Nitrogen?
• Phosphorous?
• Carbon?

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IV. The third category of pollutant to examine is
biostimulants. (cont.)

• D. How are biostimulants introduced into the
  non-point source pollution flow.
• 1. Atmospheric scrubbing, wetfall. Nitrogen
• There are places, where, for example the use of
  automobiles is heavy, the amount of nitrogen
  compounds in rainfall is significant. Examples
• The Los Angeles Basin
• The Industrial Eastern U.S.
• Lake Tahoe (The largest source of nitrogen is
  raindrops hitting the lake)

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IV. The third category of pollutant to examine is
biostimulants. (cont.) D. How are biostimulants
introduced into the non-point source pollution
flow. (cont.)

• 2. Excess fertilizer run-off. Both an urban and
  rural problem. Nitrogen and Phosphorous
• Think about golf courses.
• 3. Run-off rich in animal excrement. Carbon,
  Nitrogen, and Phosphorous
• Stockyards, pig farms, Central Park in New York
  (all the dogs).
• 4. Excess plant material. Could be urban or
  rural. Carbon, Nitrogen, and Phosphorous