Organic Compounds in Water and Wastewater Origins of NOM I Lecture - PDF document

9/18/2014 Print version CEE 697z Organic Compounds in Water and Wastewater Origins of NOM I Lecture #4 Dave Reckhow - Organics In W & WW Outline  Engineering Concerns  NOM in Source Waters  Origins  Classifications  Concentrations  Characterization of NOM  Basic properties It’s one of my favorite recipes. I call it  Useful methods Humic Acid  Reactions with Disinfectants  Compounds formed  Amounts formed: Precursor tests 2 2 1

9/18/2014 Source of NOM  Where  Pedogenic  Aquogenic  Factors  Geology  Flora  Climate  Land use  Hydrology 3 Some definitions Groupings Based on Origin  autochthonous material is formed within the water body  allochthonous material can originate from either the soil or from upstream water bodies  aquagenic , substances originating from any water body  pedogenic for substances originating from soil 4 2

9/18/2014 Precursors:Watershed Origins Upper Soil Horizon Lower Soil Horizon Litter Layer Lake Algae Aquifer Sediment & Gravel in Lake Bed 5 Watershed Origins Lake Algae Aquifer Sediment & Gravel in Lake Bed 6 3

9/18/2014 DOC Generation  What do we know?  Start with the “building blocks”  Link to chemical characterization “I think you should be more explicit here 7 in step two” The terminology  Humic substances  Fulvic & Humic Acid  Non-humics  Many are Structurally Defined  Many are simple plant products  Tannins, Aromatic Acids and Phenols  Carbohydrates, sugars  Fatty Acids  Amino Acids and Proteins  T erpenoids  Miscellaneous Low MW Compounds  Acylheteropolysaccharides are in this group too  Structural sugars containing nitrogen 8 8 4

9/18/2014 NOM: Origins & Behavior  Humic substances (humic and fulvic acids)  Organic detritus modified by microbial degradation  lignin origin vs microbial  resistant to further biodegradation  “old” organics  easier to remove by coagulation  Non-humics & Structurally-defined groups  may be relatively “new”  includes many biochemicals and their immediate degradation products  generally more biodegradable  concentrations are highly variable with season 9 Origins  Humic substances (humic and fulvic acids)  Organic detritus modified by microbial degradation  lignin origin vs microbial  resistant to further biodegradation  “old” organics  Non-humics & Structurally-defined groups  may be relatively “new”  includes many biochemicals and their immediate degradation products  generally more biodegradable  concentrations are highly variable with season 10 5

9/18/2014 CO 2 NOM Types Vascular Plants  Three Algae Biodegradation NOM h  Pools Simple Plant Products :Nu El Humic Acylhetero Substances polysaccharides 11 Simple Plant Products: Metabolic Pathways Steroids Nucleic Porphyrins Acids Water Soluble Acids Terpenoids Amino Acids Mevalonic acid Misc. N & S compounds Acetate Flavonoids Unsaponifiable Liquids Pyruvate Proteins Shikimic Acid Saponifiable Liquids Carbohydrates Nitrogenous Aromatic Compounds precursors 12 From: Robinson, 1991 Activated non-N precursors 6

9/18/2014 Aged leaves from 3 locations in Wachusett watershed Leaching Experiments White White Red Oak Pine Maple 13 Plant biopolymers  Cellulose  Lignin  Phenyl-propane units  Cross-linked  Radical polymerization  Ill defined structure  Hemicellulose  Terpeniods  Proteins 7

9/18/2014 Leaching Rates  Leaching rates from the scientific literature  Amount released each week  Diminishes with time for some, accelerates for others From: Magill and Aber, 2000 Soil Biology & Biochemistry, vol. 32, pp.603-613 Composition of an “average” leaf  250 g/m 2 /yr EABP Highly- colored Some color 16 Dave Reckhow 8

9/18/2014 Variations based on Species  Source:  Terrestrial Ecosystems  Aber & Melillo  2 nd edition  Harcourt Academic Press Colored Compounds  Phenolic Acids  Readily released, highly colored  Lignin  Very slowly released, some color 9

9/18/2014 Colorless Compounds  Simple sugars  Readily released, highly biodegradable  Starch  Easily released and also biodegradable  Cellulose & Hemicellulose  Slow to solubilize, not easily degraded Constituents degrade at different rates  “Solubles” go first  Free carbohydrates are next  Bound or Lignified carbohydrates and Lignin are last 10

9/18/2014 Solubilization vs Total Loss  DOC-C loss versus total C loss in mg C. Maple Y -axis values are mean leached DOC concentration for the 15 week treatment Oak X -axis values are total C loss from litter. Pine Re-drawn from Magill and Aber, 2000 H OH Chemical Tannins, Aromatic Acids C C Symbols C C OH and Phenols C C H OH  About 0.5% of Total HO  Plant Products OH H HO O  Likely THM Precursors OH  Source of Color & DBPs HO H H O OH HO H OH H 2 Condensed Tannin HO C O C HO O CH OH HO Gallic Acid monomers HO C O CH HO CH O OH HO Hydrolyzable Tannin HO C O CH 2 22 HO 11

9/18/2014 Tannins, Aromatic Acids and Phenols, cont. •Lignin monomers COOH COOH OCH 3 OH OH Vanillic Acid p-Hydroxybenzoic Acid 23 Lignin From: Perdue & Ritchie, 2004 24 12

9/18/2014 Lignin degradation Oxidation of model lignin by ligninase & H 2 O 2 (from Kirk & Farrell, 1987) 25  To next lecture Dave Reckhow - Organics In W & WW 13