Fundamental Concepts: Fundamental Concepts: Overview of Water QualityOverview of Water Quality

Ann KenimerAnn KenimerTexas A & M UniversityTexas A & M University

University Curriculum Development for University Curriculum Development for Decentralized Wastewater Decentralized Wastewater

ManagementManagement

NDWRCDP DisclaimerNDWRCDP DisclaimerThis work was supported by the National Decentralized Water This work was supported by the National Decentralized Water Resources Capacity Development Project (NDWRCDP) with Resources Capacity Development Project (NDWRCDP) with

funding provided by the U.S. Environmental Protection Agency funding provided by the U.S. Environmental Protection Agency through a Cooperative Agreement (EPA No. CR827881through a Cooperative Agreement (EPA No. CR827881--0101--0) 0) with Washington University in St. Louis. These materials have with Washington University in St. Louis. These materials have

not been reviewed by the U.S. Environmental Protection not been reviewed by the U.S. Environmental Protection Agency. These materials have been reviewed by Agency. These materials have been reviewed by representatives of the NDWRCDP. The contents representatives of the NDWRCDP. The contents

of these materials do not necessarily reflect the views and of these materials do not necessarily reflect the views and policies of the NDWRCDP, Washington University, or the U.S. policies of the NDWRCDP, Washington University, or the U.S.

Environmental Protection Agency, nor does the mention of trade Environmental Protection Agency, nor does the mention of trade names or commercial products constitute their endorsement or names or commercial products constitute their endorsement or

recommendation for use.recommendation for use.

CIDWT/University DisclaimerCIDWT/University DisclaimerThese materials are the collective effort of individuals from These materials are the collective effort of individuals from

academic, regulatory, and private sectors of the academic, regulatory, and private sectors of the onsite/decentralized wastewater industry. These materials have onsite/decentralized wastewater industry. These materials have

been peerbeen peer--reviewed and represent the current state of reviewed and represent the current state of knowledge/science in this field. They were developed through a knowledge/science in this field. They were developed through a series of writing and review meetings with the goal of formulatiseries of writing and review meetings with the goal of formulating ng a consensus on the materials presented. These materials do not a consensus on the materials presented. These materials do not

necessarily reflect the views and policies of University of necessarily reflect the views and policies of University of Arkansas, and/or the Consortium of Institutes for Decentralized Arkansas, and/or the Consortium of Institutes for Decentralized

Wastewater Treatment (CIDWT). The mention of trade names or Wastewater Treatment (CIDWT). The mention of trade names or commercial products does not constitute an endorsement or commercial products does not constitute an endorsement or

recommendation for use from these individuals or entities, nor recommendation for use from these individuals or entities, nor does it constitute criticism for similar ones not mentioned.does it constitute criticism for similar ones not mentioned.

CitationCitation

Kenimer, Ann L., J. Kenimer, Ann L., J. VilleneuveVilleneuve and S. and S. SheldenShelden. . 2005. Fundamental Concepts: Water Quality 2005. Fundamental Concepts: Water Quality --Power Point Presentation. Power Point Presentation. inin (M.A. Gross and (M.A. Gross and N.E. Deal, eds.) University Curriculum N.E. Deal, eds.) University Curriculum Development for Decentralized Wastewater Development for Decentralized Wastewater Management. National Decentralized Water Management. National Decentralized Water Resources Capacity Development Project. Resources Capacity Development Project. University of Arkansas, Fayetteville, AR.University of Arkansas, Fayetteville, AR.

Water PollutionWater Pollution

Definition: any condition that adversely Definition: any condition that adversely affects the quality of streams, lakes, affects the quality of streams, lakes, oceans, or groundwater oceans, or groundwater

Water Pollution ImpactsWater Pollution Impacts

Unpolluted water has a wide diversity of Unpolluted water has a wide diversity of aquatic organisms and contains enough aquatic organisms and contains enough dissolved oxygendissolved oxygenPolluted water inhibits the growth of Polluted water inhibits the growth of aquatic organismsaquatic organisms

Reference MaterialReference Material

Standard Methods for the Analysis of Standard Methods for the Analysis of Water and WastewaterWater and Wastewater. American Water . American Water Works Association and the American Works Association and the American Public Health Association.Public Health Association.EPA Methods and Guidance for the EPA Methods and Guidance for the Analysis of WaterAnalysis of Water. US Environmental . US Environmental Protection Agency.Protection Agency.

Organic CompoundsOrganic Compounds

An An organic compoundorganic compound is a substance that is a substance that contains carbon.contains carbon.

Cyanide, cyanates, carbon dioxide and its Cyanide, cyanates, carbon dioxide and its relatives are exceptionsrelatives are exceptions

Importance of Organic MatterImportance of Organic Matter

Organic material consumes oxygen in Organic material consumes oxygen in waterwaterOrganic material can cause taste and odor Organic material can cause taste and odor problems in recreational and drinking problems in recreational and drinking waterwaterSome material may be hazardousSome material may be hazardous

Dissolved OxygenDissolved Oxygen

Dissolved oxygen is oxygen that has been Dissolved oxygen is oxygen that has been incorporated into waterincorporated into waterMany aquatic animals require it for their Many aquatic animals require it for their survivalsurvival

Dissolved OxygenDissolved Oxygen

There are two important factors that can There are two important factors that can influence the amount of dissolved oxygen influence the amount of dissolved oxygen presentpresent

Water temperatureWater temperatureOrganic matterOrganic matter

Dissolved OxygenDissolved Oxygen

Temperature:Temperature:Greater temperature Greater temperature Lower saturated Lower saturated DODOLower temperature Lower temperature Greater saturated Greater saturated DODO

Dissolved OxygenDissolved Oxygen

Organic materialOrganic materialIf oxygen is available, organic material If oxygen is available, organic material requires oxygen to decomposerequires oxygen to decomposeOrganic material may also decompose in the Organic material may also decompose in the absence of oxygenabsence of oxygenMore organic material requires more DO, and More organic material requires more DO, and will tend to deplete water of DOwill tend to deplete water of DO

Oxygen DemandOxygen Demand

The The oxygen demandoxygen demand is the amount of is the amount of oxygen required to aerobically oxidize a oxygen required to aerobically oxidize a materialmaterial

Biochemical Oxygen DemandBiochemical Oxygen Demand

Biochemical oxygen demandBiochemical oxygen demand, or BOD is , or BOD is the amount of oxygen used by organisms the amount of oxygen used by organisms during the breakdown of organic materialduring the breakdown of organic materialBOD is considered an indirect measure of BOD is considered an indirect measure of the organic content of a samplethe organic content of a sample

BODBOD

BOD analysis is done under these BOD analysis is done under these conditions:conditions:

Must be in the darkMust be in the darkMust be at 20Must be at 20ººCCMust have an excess of nutrientsMust have an excess of nutrients

BODBOD55 ProcedureProcedure

Measure initial DOMeasure initial DOIncubate sample for 5 daysIncubate sample for 5 daysMeasure final DOMeasure final DOThe BODThe BOD55 is directly related to the amount is directly related to the amount of DO used up over the 5of DO used up over the 5--day periodday period

BODBODBODBODt t = BOD at t days (= BOD at t days (mgmg//LL))DODOii = Initial DO (= Initial DO (mgmg//LL))DODOff = Final DO (= Final DO (mgmg//LL))VVss = Volume of sample (L)= Volume of sample (L)VVb b = Volume of BOD bottle (L)= Volume of BOD bottle (L)

bVsV

fDOiDO

tBOD−

=

Ultimate BODUltimate BOD

The The ultimate BODultimate BOD measures the total measures the total amount of oxygen needed to oxidize the amount of oxygen needed to oxidize the organic matter and the reduced organic matter and the reduced nitrogenous compounds.nitrogenous compounds.

BOD carbonaceous + BOD nitrogenous = BOD carbonaceous + BOD nitrogenous = ultimate BODultimate BOD

Chemical Oxygen Demand (COD)Chemical Oxygen Demand (COD)

CODCOD is the equivalent amount of oxygen is the equivalent amount of oxygen needed to break down organic matter and needed to break down organic matter and oxidize nitrogen compounds using strong oxidize nitrogen compounds using strong oxidizing agentsoxidizing agents

Chemical Oxygen DemandChemical Oxygen Demand

Another means of measuring oxygen demand Another means of measuring oxygen demand needed to oxidize organics and reduced needed to oxidize organics and reduced nitrogenous compounds nitrogenous compounds Faster than BODFaster than BODAlways higher than BODAlways higher than BOD

COD is much higher than BOD in raw wastewatersCOD is much higher than BOD in raw wastewatersCOD:BOD ratio is usually less than 2:1 in treated COD:BOD ratio is usually less than 2:1 in treated effluentseffluents

COD:BOD ratio is dependent on circumstances COD:BOD ratio is dependent on circumstances and reduces with treatmentand reduces with treatment

Total Organic CarbonTotal Organic Carbon

Total organic carbonTotal organic carbon, or , or TOCTOC, is the , is the amount of organic carbon bound in a amount of organic carbon bound in a sample.sample.

Fats, Oil, and GreaseFats, Oil, and Grease

Generally listed under one heading called Generally listed under one heading called FOGFOG (fats, oils, and grease) as it is often (fats, oils, and grease) as it is often not important to know the exact makenot important to know the exact make--up up of this group of componentsof this group of components

SolidsSolids

Cause many problems:Cause many problems:Collect in septic tank requiring pump out Collect in septic tank requiring pump out over timeover timeMay clog distribution areas in poorlyMay clog distribution areas in poorly--managed systemsmanaged systemsFill storage areas, clog ditches and Fill storage areas, clog ditches and channelschannelsSettle on stream bottoms resulting in Settle on stream bottoms resulting in death of valuable benthic biota and loss of death of valuable benthic biota and loss of habitat and dissolved oxygen in the water habitat and dissolved oxygen in the water column column

Total Solid (TS)Total Solid (TS)

Total solidsTotal solids of a sample is the matter left of a sample is the matter left behind after drying a sample of water at behind after drying a sample of water at 105105ººCC

Total SolidsTotal Solids

There are two ways that solid materials may There are two ways that solid materials may be classifiedbe classifiedSuspended solidsSuspended solids and and dissolved solidsdissolved solidsVolatile solidsVolatile solids and and fixed solidsfixed solids

SolidsSolids

Total suspended solidsTotal suspended solids are the part of the are the part of the sample that may be caught with a 1.5 sample that may be caught with a 1.5 µµm m filterfilterTotal dissolved solidsTotal dissolved solids are the part of the are the part of the sample that will pass through the filtersample that will pass through the filter

SolidsSolids

Total volatile solidsTotal volatile solids is the portion of the is the portion of the sample lost after the sample has been sample lost after the sample has been heated to 550heated to 550ººC. It is an approximation of C. It is an approximation of the organic material presentthe organic material presentTotal fixed solidsTotal fixed solids is the portion that still is the portion that still remains after heating. It is an remains after heating. It is an approximation of the mineral matter approximation of the mineral matter presentpresent

SolidsSolids

These categories may be combined:These categories may be combined:Volatile dissolved solids (VDS)Volatile dissolved solids (VDS)Volatile suspended solids (VSS)Volatile suspended solids (VSS)Fixed dissolved solids (FDS)Fixed dissolved solids (FDS)Fixed suspended solids (FSS)Fixed suspended solids (FSS)

SolidsSolids

SolidsSolids

The mass of solids per known volume of The mass of solids per known volume of water is:water is:

S = Solids concentration (mg/L)S = Solids concentration (mg/L)mmtt = Mass of solids and container (mg)= Mass of solids and container (mg)mmcc = Mass of container (mg)= Mass of container (mg)Vol = volume of liquid sample (L)Vol = volume of liquid sample (L)

volmmS ct −=

NutrientsNutrients

Problems associated with excess nutrients:Problems associated with excess nutrients:

Causes an increase in productivity of Causes an increase in productivity of aquatic plants, leading to depleted DO aquatic plants, leading to depleted DO levelslevelsMay cause odor problemsMay cause odor problemsExtra vegetation near surface may inhibit Extra vegetation near surface may inhibit penetration of light into waterpenetration of light into water

NutrientsNutrients

Macronutrients:Macronutrients:NitrogenNitrogenPhosphorusPhosphorusPotassiumPotassium

Microbial OrganismMicrobial Organism

Serve many important purposes including Serve many important purposes including degrading waste materialsdegrading waste materialsSome of them may be dangerous to Some of them may be dangerous to human health and must be removed from human health and must be removed from waterwater

Testing for Microbial OrganismsTesting for Microbial Organisms

Fecal coliform counts are used as an Fecal coliform counts are used as an indicator organismindicator organismThe sample material is placed in a nutrient The sample material is placed in a nutrient bath and set aside in a sterile areabath and set aside in a sterile areaThe number of colonies that form are The number of colonies that form are proportional to how many microbial proportional to how many microbial organisms are present in a sampleorganisms are present in a sample

SaltsSalts

Problems associated with excess salt:Problems associated with excess salt:High salt concentrations detrimental to High salt concentrations detrimental to plant growth and can damage crops plant growth and can damage crops Salt can damage equipment, especially Salt can damage equipment, especially some materials which react with the saltssome materials which react with the salts

MetalsMetals

Problems associated with excess metals:Problems associated with excess metals:Can make water taste and smell badCan make water taste and smell badCan stain Can stain Metals in high enough concentrations are Metals in high enough concentrations are pollutants and can be serious health risks.pollutants and can be serious health risks.

TurbidityTurbidity

TurbidityTurbidity is a measure of the clarity of is a measure of the clarity of water.water.Turbidity is influenced by the number of Turbidity is influenced by the number of insoluble particles presentinsoluble particles present

HardnessHardness

HardnessHardness is the concentration of is the concentration of multivalent cations.multivalent cations.Hard water can leave scales in pots, Hard water can leave scales in pots, pipes, and hot water heaters. More soap pipes, and hot water heaters. More soap is also needed to clean.is also needed to clean.Soft water has fewer cations making it Soft water has fewer cations making it harder to remove soap residue.harder to remove soap residue.

pHpH

pHpH is the negative log of the hydrogen ion is the negative log of the hydrogen ion concentrationconcentrationIt can have a major impact on biological It can have a major impact on biological and chemical reactionsand chemical reactions

AlkalinityAlkalinity

AlkalinityAlkalinity is the capacity of water to absorb is the capacity of water to absorb hydrogen ions without significant pH hydrogen ions without significant pH changechangeBicarbonates, carbonates, and hydroxides Bicarbonates, carbonates, and hydroxides are the three chemical forms that are the three chemical forms that contribute to alkalinitycontribute to alkalinity