Raw Water Quality Loughborough, UK

© R Harries 2012 Raw Water Quality Loughborough, UK. Richard RHarries Richard Consultant © R Harries 2012 Water © R Harries 2012 Shallow Borehole SUBSUB--SURFACE Deep Borehole Raw Water – Where Does It ComeFrom? Where DoesIt Raw Water– WATER SURFACE River Water SURFACE Reservoir WATER Lake WATER SOURCE Process Condensate Treated Sewage Cooling Water RECOVERED RECOVERED WATER Effluent BRACKISH WATER SEA WATER Desalinated Pre-Treated © R Harries 2012 • • Sub-Surface Water Sources Sub-Surface Water Shallow Borehole Deep Borehole • • • • • • Potential for greater variability Potential for greater gravels e.g. porous strata, in Often May vary in minor ways dependent on depth of pumping fromborehole. ofpumping dependent ondepth minor waysMay varyin Relatively constant composition Relatively constant May be “old”geologically drawn is it which from strata rock of is characteristic Composition • • • Dependent on rainfall pattern Dependent onrainfall holes” “sink or rivers local from Intrusion Chemical constituents and temperature and constituents Chemical © R Harries 2012 • • • ufc ae Rivers(1) Surface Water- area, rainfall, seasonal factors seasonal area, rainfall, canRiver depending quality bevery catchment water variable on sizeofriver, Composition depends on geological strata with which water has been in contact beenin waterhas which Composition stratawith depends ongeological Wide variety ofcompositions • • Limestone / chalk strata chalk / Limestone Igneous rocks e.g. granite e.g. rocks Igneous • • • • • • Lower levels of organic matter Lower oforganic levels high bicarbonatealkalinity High hardness and content solids dissolved Higher silica colloidal including solids, producesuspended and colloidal may River inspate peat moorland from if and colour High organics content solids Low dissolved © R Harries 2012 ufc ae Rivers(2) Surface Water - • • Stratification Composition also dependent on discharges into rivers Composition ondischargesinto also dependent • • • • Can occur in deep and slow moving moving rivers Can occurindeepandslow Agricultural Drainage Agricultural Municipal Discharges Industrial Discharges Industrial • • • • • • • • • General surface drainage (suspended solids) (suspended drainage General surface sulphate) phosphate, nitrate, potassium, (ammonium, Fertilisers matter) and organic (ammonia wastes animal Slurries and Surface drainage Surface untreated) or Sewage effluent(treated Oils, greases and disturbance of sediments navigable rivers on ofsediments disturbance and greases Oils, andhighinmetals) Mine drainage (acidic CaandCl) highin GasDesulphurization, (e.g. Flue Power plantwaste water water waste Process © R Harries 2012 • • ufc ae -ReservoirsandLakes Surface Water- Storage Reservoirs Catchment (Retention) ReservoirsandLakes • • • • • • • Consequent variability in composition Consequent variability in rivers from abstracted Often onavailability dependant sources multiple fed from May be Can be low in dissolved solids,highinorganics Can belowindissolved upland areas drain Often source into which feed rivers to characteristics Similar courses water Supplied by natural • • Larger reservoirs even outvariations Larger reservoirs ofreservoir Depends onsize © R Harries 2012 Isles British of the Geology © R Harries 2012 • • • Potable vsNon-Potable Non Potable Potable been has Fundamentally no differencerelative to treatmentbyionexchange. • • • • • Often requires pre-treatment requires Often Composition may be variable due to blending due to Composition may be variable Low insuspended solids Disinfected Pre-treated • • • Not disinfected – potentially microbiologically active microbiologically potentially – Not disinfected TOC in Reduction matter solidsandcolloidal suspended Removal of © R Harries 2012 • • • • Recovered Water Treated Effluent Sewage Recovered ProcessCondensates Process Cooling Water Process Cooling Covers a varietyofpotentialsources. • • • • • • • • Risk of organic / microbiological microbiological contamination / organic Risk of water to surface similar should be Composition Temperature can be up to 100 canbeup Temperature risks contamination assess to Need process(es) party Need tounderstandthird May have added chemicals for disinfection / corrosion control corrosion / disinfection for added chemicals May have evaporation dueto concentrated bemore may – above ambient Temperature supply water Often surface o C © R Harries 2012 • • Desalinated Water Reverse Osmosis Desalination Reverse Osmosis Thermal Desalination • • Impurities in desalinated water are: waterin desalinated Impurities Impurities in desalinated water are: waterin desalinated Impurities • • • • • • • • Carbon dioxide passes through RO membrane degassing and requires RO membrane through Carbon dioxidepasses Low inTOC stages ofRO number depends on Concentration /rejection selectivity membrane Dependant on Generally low in concentration ofGenerally lowinconcentration allspecies carry-over Dependent ondroplet removed alkalinity had bicarbonate have may Water water source of Representative © R Harries 2012 • • • • • nltclDt General Requirements AnalyticalData – Microbiological activity Oxidants Soluble colloidal organic matteror Non ionic species Non ionic Ionic species Ionic • • • • which may interfere with the process or affect the product quality. theproduct affect or the process with which may interfere particulate or colloidal suspensions which interfere with the process. the with interfere which suspensions orcolloidal particulate in minor concentrations which may have adverse influence of the process. ofthe influence haveadverse which may concentrations in minor design. process basic the affect that exchange for withpotential - which may attack the resins the attack which may - which may foul resin beds foulresin which may - . © R Harries 2012 • • nltclDt Trend Data AnalyticalData – pH Conductivity • • • • • • Also highlights changes in composition contamination or composition in highlights changes Also conductivity than Less accurate Non specific Useful indicator for tracking changes in composition in changes tracking for indicator Useful measurement accurate and Simple Non specific • HCO 3 - / CO 3 2- equilibrium linked to pH to equilibrium linked © R Harries 2012 • • • nltclDt Units Analytical Data– It is not unusual mixedunits!!It isnotunusual to getanalyseswith Current of concentration units Historically Historically a variety ofunits have been used to express the analysisof water. • • • • • • Be careful m mol/l of individual ion (Do not use to calculate ionic balance.) calculate to not use individual ion(Do of m mol/l (alsomval/l) meq/l of individualion ofindividualion mg/l mg/l CaCO mg/l equivalents are no longer officially recognised! longer officially equivalents are no but ionic charge), (i.e. basis equivalent chemical a on worksIon exchange 3 (Conversion to a common base.) a common (Conversion to © R Harries 2012 • • • • • • nltclDt -Definitions AnalyticalData - titration to methyl orange end point.. It is usually reported as mg CaCO as mg reported is usually It point.. orangeend tomethyl titration Total alkalinity CaCO as mg reported usually is anions. It bicarbonate Total Alkalinity (TAlk) removed by boiling. It is usually reported as mg CaCO as mg reported is usually It by boiling. removed can be it because Called “temporary” Mg. Ca + with anionsassociated bicarbonate Temporary Hardness (TH) CaCO acids (SMA) Equivalent Mineral Acidity(EMA) CaCO as mg reportedusually is It etc). Fe, Mn Mg, Ca, (i.e. cations metal transition Total Hardness(TH) may be reported in mg/l or ppm or milliequivalents/l CaCO mg or milliequivalents/l ppm or or in mg/l reported be may (TDS) Total DissolvedSolids 3 3 /l /l sulphate, chloride and nitrate anions. It is usually reported as mg as mg reported usually is It anions. andnitrate chloride sulphate, is sometimes referred to as to referred is sometimes is the sum of the concentration of soluble alkaline earthand alkaline ofsoluble concentration the of the sum is is the total concentration of hydroxide, carbonate and carbonate hydroxide, of concentration total is the or bicarbonate hardness, is the concentration concentration isthe hardness, or bicarbonate is the total concentration of cations and anions. It It andanions. cations of concentration total is the is the total concentration ofthe concentration the total is M-Alk i.e. alkalinity measured measured by alkalinity i.e. 3 3 /l /l 3 /l strong mineral mineral strong 3 /l © R Harries 2012 • nltclDt Analytes AnalyticalData - Cations • • Note: The ratio of ionic species is important inionexchange speciesisimportant Note: Theratioofionic Interference Parameters Interference Process Parameters Process • • • • • • regeneration only) (H Strontium Barium, Manganese soluble) and (total Aluminium Iron, (particularly forcondensates) (particularly Amines ion, Ammonium Magnesium Calcium, Potassium, Sodium, 2 SO4 • Anions • • Interference Parameters Interference Process Parameters Process • • • • • • Phosphate, Fluoride Phosphate, Carbon Total Organic silica) reactive, colloidal includesnon - Silica (Total Silica (reactive – i.e. soluble) i.e. – Silica (reactive carbonate / Bicarbonate Alkalinity = Nitrate Sulphate, Chloride, © R Harries 2012 Bicarbonate / Carbonate Equilibrium vspH Equilibrium Bicarbonate /Carbonate © R Harries 2012 • • • nltclDt OtherEssentials AnalyticalData – Microbiological Activity Residual Oxidants (residual chlorine) Residual Oxidants Suspended Solids • • • Fouling potential resins on attack Chemical Fouling potential (e.g. untreated sewage) untreated (e.g. © R Harries 2012 • • • ore fDt PotableSupplies Sources ofData– anproei ulchat “potablequality” health– public purpose Main is frequently and some(e.g.SiO Most forIXtreatmentnotanalysedvery of interest are of theparameters Potable Water Suppliers have quality records which are available topublic. areavailable Suppliers Potable havequalityrecordswhich Water • • • • meets national and international standards (EU, WHO, etc) WHO, (EU, standards international and national meets quality aslongit waterThe userhasnoleverageoverpotable industrial Suppliers often reluctant to part with data with to part reluctant Suppliers often value practical limited – figures frequent) (or less based onquarterly as annualaverages Often quoted supply boundary). supply near a (e.g. likely sources supply multiple or if supplyarea Need toknow 2 ) not at all. © R Harries 2012 • • • ore fDt SurfaceWaters(1) Sources ofData– Publish Publish annual averages as quarterlyor The data of interest for IX design / operation is limited infrequency The /operationislimited of analysis.data ofinterestforIXdesign Environment Environment Agency(UK) publishpublicrecords onriverquality, • • • • • No value to pick out short term variations. term out short pick No valueto variability. of trends long term establish Useful to Similar to potable supplies potable supplies, potablesupplies, supplies Similar to potable Can be difficult to access on-line, unless licensed. unless on-line, access to difficult Can be points. sample many data and Good historical © R Harries 2012 • • • ore fDt SurfaceWaters(2) Sources ofData– You may haveto ask alotofpeopleordoyour own research. What is the likelihood of any of these impacting on yoursupply quality? Questions toask • upstream? source supply water your feed into ofcontamination sources Do otherpotential • • • Other rivers likely to change character suddenly tochangecharacter likely Other rivers discharges plant Sewage treatment effluents process Industrial © R Harries 2012 • • • • Sources ofData–Surface (3) Waters What is the size of the reservoir and rate of turnover? the reservoir andrateof of What is thesize Collection or storage reservoir? Collection orstorage a reservoir? Does originatefromorvia the water questions More • • • organics, may be redistributed through the year. throughthe redistributed maybe organics, and resulting algal blooms e.g. seasonal variations, > 1year, If turnover Storage reservoir may be fed from multiple sources multiple fed from be may reservoir Storage area catchment specified from waters natural in takes Collection reservoir © R Harries 2012 • • • nltclDt All Sources Analytical Data– analytical error!!!! Never unless discard asampling sure an outlier youor are absolutely it is Check if there is an ionic balance, based on equivalents (meq/l) balance,basedonequivalents anionic Check there is if Third party dataislikelytobeaveraged overaperiodoftime:up to 1year. • • If balance < 90% query or reject data. or reject <90%query If balance be gooddata to 95% likely balance > If in © R Harries 2012 • • • • nltclDt SelfGenerated AnalyticalData – Local knowledge isinvaluable!!!! Local knowledge party data. Set sampling up yourown and analysisprogramme to crosscheckthird have records. more usefulanalytical Arethere other industries already treating thesame water supply.They may heshouldcontract stipulates do so!! evenifthe behalf – Do not relyon yourIX plantormain contractor toobtain any data onyour © R Harries 2012 • • How Much Data? How Much Historical data requirement source. Historical datarequirement of thewater depends onvariability NWR Asmuchaspossible! ANSWER: – • • • • • • Large rivers can show significant andannualvariation significant seasonal can show Large rivers variation seasonal to susceptible less Deep boreholes If there is more historical data check key parameters for variability. for parameters key data check historical more is If there data. fiveyears least Ideal at data. seasonal twoyears atleast Preferable year). (1 seasons over four is data minimum Absolute © R Harries 2012 • Total Organic Carbon Total Organic A non watersamples specific measureoforganic matter in • • • • • being measured organics to appropriate TOC instrument of conditions oxidation Calibration and growth microbiological minimise to conditions refrigerated under Sample storage bottles glass clean into Sampling requires care: measurement oxidation Thermal Chemical oxidation measurement (e.g. persulphate and UV enhanced) and persulphate (e.g. measurement Chemical oxidation • • • Be aware of potential errors in the measurement in the errors Be awareof potential C Inorganic Total C– TOC =Total (TC) carbon total and carbon (TIC) inorganic total Also measures © R Harries 2012 • aua O Humic /Fulvic Acids Natural TOC - Product Product vegetative decay of • • • • • • • Difference between humic and fulvic acids andfulvic humic Difference between 500,000 5,000 – Molecular weights holes sink via boreholesystems shallow to May ingress boreholes Not foundindeep sources water intonatural towashorganics Dependent onrainfall nature seasonal in Often cover high tree andareasof moors From peat • • • Humic acid insoluble at pH 1; higher MW; lower ratio of oxygen to carbon of oxygen lower ratio MW; higher atpH1; insoluble Humic acid to carbon oxygen of higherratio lower MW; atpH1; Fulvic acidsoluble acidity Both have carboxylate © R Harries 2012 TOC – Schematic of Fulvic Acid Fragment (MW ~ 1000)(MW Fragment of FulvicAcid Schematic TOC – © R Harries 2012 aua O AlgalBlooms (DiatomsAndPolysaccharides) Natural TOC – • • Sequential seasonal growth pattern Sequential seasonalgrowth Algal blooms Algalblooms are generallysummertime sources ofTOC • • • • • • legenage–lateseason Blue greenalgae– season mid – Green algae Diatoms - early season early - Diatoms Generally occur in large open storage reservoirs openstorage inlarge Generally occur Require energysource:sunlight phosphate , nitrate Require nutrients: • • • • Cause foaming in degassers and during anion exchange regeneration exchangeduring anion indegassersand Cause foaming IX by completely remove to Difficult poly-saccharides By-products are Microscopic silica based skeleton – non reactive silica reactive non – skeleton based silica Microscopic © R Harries 2012 • aua O DOCClassification Natural TOC – DOC =DissolvedOrganicCarbon • • Remains non specific – peaks given attributions peaks – specific Remains non technique Liquid chromatographic • • • • • • Low molecular Low molecular organic acids. weight Low molecular neutrals andamphiphilics weight /fulvics) humics of products blocks (Breakdown Building fulvics / humics – substances Humic proteins / Polysaccharides includes – Bio-Polymers Hydrophobics © R Harries 2012 • • • Other SourcesOrganic Matter ofTOC/ Organics may be emulsified or floating on the surface of a water supplyOrganics may be emulsifiedorfloatingonthesurfaceofawater Condensates Water and Recovered Natural andSurfaceWaters • • • • • • Difficult to obtain representative sample sample representative to obtain Difficult Other process organics process Other oils and fats Process Lubricating oils Other organicspillages source Oil spillageintowater © R Harries 2012 • • • • O Interpretation ofData TOC – Review technology optionsforpre-treatment. Pilot scale tests mayberequired Local knowledge is the most valuable factor most valuable Local knowledge is the Concentration oftreatment. is noguide to thedifficulty • • • Frequency of events and variability of the water supply the water of and variability Frequency ofevents contamination Known sourcesof water same the treating sites Other © R Harries 2012 nepeaino O nlss–Historical Data Interpretation of TOC Analyses– Ultraviolet (UVOxidation) KMnO KMnO KMnO oxidation) thermal TOC (Wetor 4 4 4 – 10 min boil(Kubel) 10min – 4hrat27ºC – – 30 min at100 30min – Method o C 3 ppm as CO as 3 ppm 4 ppm as KMnO as 4 ppm O as 1 ppm 8 to 10 ppm as KMnO ppm as 8 to10 as O ppm 2 to2.5 12 ppm as KMnO as 12 ppm O as 3 ppm 1 ppm as C as 1 ppm Relative Concentration Relative (Approximate) 2 2 2 4 4 2 4 © R Harries 2012 • • Condensates – Conventional Power Plant Power Conventional Condensates – ra2–Recovered “cleanwater” Area2 – ra1–Condensate polishing Area1 – • • • • • • • • • Temperatures can be variable up to 100 upto canbevariable Temperatures waterdump start-up of large volumes Potentially Lubricating oils oxides metal Particulate impurities ofionic Low concentrations eprtrstpcly3 50 – 30 typically Temperatures dependent kinetic is exchange – High flowrate disturbances system at oxides metal Particulate impurities ofionic Low concentrations o C o C © R Harries 2012 • • • Process Condensates - (e.g. Combined Heat & Power Plant) & Power Combined Heat (e.g. - Process Condensates Knowledge of processes essential to understand contamination risk contamination understand to essential processes Knowledge of Condensate may require cooling for treatment for cooling mayrequire Condensate recovery aswater as important Heat recovery • • • • Contamination risks (examples) risks Contamination Cu alloycontent high e.g. important: plant Materials in details release to reluctant often Customer Plate heat exchangers to recover heat to recover exchangersPlate heat • • • Sludges: e.g. paper pulp paper e.g. Sludges: and oils Organic chemicals Cooling water © R Harries 2012 a ae lsiiain-MajorSpecies Raw WaterClassification- Alkalinity (HCO Sulphate Chloride Magnesium Calcium Sodium IONIC SPECIES 3 - ) 12.2 mg/l 9.6 7.1 1.2 2.3 8 Water A Water “Thin” meq/l 0.2 0.2 0.2 0.1 0.4 0.1 mg/l 98 19 14 24 18 5 “Medium” Water B Water meq/l 1.6 0.4 0.4 0.4 1.2 0.8 mg/l 305 120 58 64 12 23 Water C Water “Thick” (Courtesy TVArden) meq/l 5.0 1.2 1.8 1.0 6.0 1.0 mg/l 122 250 200 48 16 5 “Brackish” Water D meq/l 2.0 1.0 7.0 0.4 0.8 8.8 © R Harries 2012 Raw Water Analyses - Alternate Potable SourcestoSingleSite Alternate Raw Water Analyses - Total cation:Total Anion TOC Silica (SiO Alkalinity (HCO Sulphate Chloride Magnesium Calcium Sodium pH Conductivity ( 2 ) ION ȝ 3 S/cm) - ) mg/l 281 535 0.2 7.3 42 36 24 79 14 9 SOURCE “A” 6.56 6.50 : meq/l 4.61 0.88 1.01 3.95 0.61 2.0 mg/l 110 1.5 7.3 34 12 14 2 9 2 4 SOURCE “B” 1.04 : 1.06 1.04 : meq/l 0.56 0.25 0.25 0.17 0.70 0.17 © R Harries 2012 Raw Water Analyses - Variation in River Composition (R Trent) (R inRiver Composition Variation - Raw WaterAnalyses pH Phosphate (asPO Silica (Reactive /Total) Conductivity Total SuspendedSolids TOC Alkalinity (HCO Nitrate Sulphate Chloride Magnesium Calcium Sodium + Potassium (as Na) 3 - ) 4 ) 10.45 / 10.5 10.45 / mg/l Early November 2007 986 212 138 7.6 6.7 4.5 10 50 91 21 92 82 [T [T meq/l Cat An 3.48 0.81 2.88 2.56 1.75 4.60 3.57 9.73] 9.92] 7.5 8.3 / mg/l Late November 2007 720 129 7.5 7.9 1.2 48 32 71 92 13 60 64 [T [T meq/l Cat An 2.12 0.52 1.48 2.59 1.08 3.00 2.78 6.71] 6.86] © R Harries 2012 (UK Water Supplies) (UK Water Species of Minor Concentrations Typical Indicative Raw Water- Residual Chlorine Aluminium (Total) Aluminium (Soluble) Iron (Total) Iron (Soluble) Barium Phosphate Suspended Solids TOC Silica (Non Reactive) Silica (Reactive) SPECIES mg/l Cl mg/l mg/l Al mg/l mg/l Al mg/l mg/l Fe mg/l Fe mg/l Ba mg/l mg/l PO mg/l mg wt)/lmg (dry mg/l C mg/l mg/l SiO mg/l SiO 2 UNITS 4 2 2 TYPICAL RANGE .2–0.05 0.02 – .2–0.2 0.02 – .2–0.1 0.02 – .5–0.2 0.05 – .2–0.5 0.02 – .5-10 0.05 - . 0.5 0.2 – . 10 0.2 - .2-2 0.02 - . 5 0.1 - 10 1 - PEAK VALUES 0 200 100 - . 0.5 0.2 – . 10 0.5 - 5-20 15 - 5-20 15 - 10 5 - 1 -3 1 -5 1 -2 5 © R Harries 2012 Water © R Harries 2012 • • • • • Design Basics (1) Design Basics Define treated water quality Define water treated Define raw water composition Define rawwater andoutlet inlet Define fortreatmentplant: termination points source(s) Define rawwater Define basic plant parameters Define basicplant • • • • This will become the contractual basis for all further negotiation / argument / negotiation all further basisfor contractual the become This will Plant availability (Can my process be shut down?)shut processbe (Canmy Plant availability plant o/s?) with operate Storage (How longcanI Throughput © R Harries 2012 • • • Design Basics (2) Design Basics Assuming dataavailable,tabulatethefollowing: sufficient value. datahaslimited on limited analysisStatistical aspossible. information Give thecontractorasmuch • • • Note peak values, even if you are unsure ofveracity. are unsure if you Note peakvalues,even point 95% percentile 90% or say at range, min – i.e. max Variability, balance) ionic (checking Average values • are often true and can rebound onyou! and can are oftentrue They them. not believe youdo because just peakvalues Do notdiscard © R Harries 2012 • Conclusions – Raw Water Source Raw – Conclusions Understand supply.as muchpossibleaboutyourraw water • • • • • • • Monitor thewaterregularly process the affect/foul may that constituents The minor any organicmatter The of nature The nature of change incomposition The natureof variability for potential Its composition its influence might What from comes it Where • • Conductivity is non specific but is very sensitive tochanges sensitive is very but specific non is Conductivity e.g. rainfall dependent, river in spate river in dependent, e.g. rainfall © R Harries 2012 • • • • ocuin DesignBasics Conclusions – Give your contractor / supplier as asGive your muchinformation possible contractor /supplier In specification of raw water composition water In specificationofraw Do not discard apparently highresults data aspossible Obtain asmuchhistorical • • • parameter each for andminimum maximum band of defined astatistically Present years data of values andnumber Present average Note them in any specification in any Note them © R Harries 2012