B Treatment

Flashcards focused on high yield/easily forgettable topics tested on the WPI Criteria

TTHM & HAA5 MCLs

.08 & .06 mg/L respectively

Pb & Cu MCLs

Action Levels = .015 and 1.3 mg/L respectively. NO MCLs, rather treatment technique.

Chlorite, Nitrite, Nitrate MCLs

1, 1, & 10 mg/L (nitrATE is 10, ITEs, are 1)

Fluoride, Chlorine, Chloramine, Cl02 MCLs

4 mg/L for Fluoride, chlorine and chloramines, 0.8 for Chlorine Dioxide

Arsenic, Cyanide MCLs

.01 and .2

Radium MCL (226 & 228 combined)

5 pCi/L

Uranium MCL

.01 mg/L

Bluestone: formula, uses, other considerations

Cu(II) Sulfate / CuSO4 (*5H2O). Algae control / microbiocide. Generally quite toxic, including somewhat to fish. useless below 60F

KMnO4 (Potassium Permanganate): Uses & Considerations

Oxidizer for Fe & Mn, T&O control

(zebra mussel/algae control, disinfectant, coagulant aid)

Consideration: strong oxidant (fire risk)

PAC: Uses & Considerations

ABSORBS: T&O compounds (Geosmin, MIB, organics), VOCs, DBP precursors (organics)

Considerations: add as early as possible, before chlorine. Is filtered out, can increase filter loading

Alum: formula, uses & considerations (lots of info)

Al2(SO4)3 / aluminum sulfate.

Primary coagulant (most commonly used): destabilizes colloidal particals via charge neutralization and sweep floc. (snowball falling effect)

pH range is 6.5-8.5. Bad in cold water

Lowers pH and alkalinity, may need to compensate (lime, soda ash, caustic)

large sludge volumes.

Jar test to optimize dose

ACH / PACL: name, formula, uses, considerations

Aluminum chlorohydrate / Polyaluminum chlorohydrate. AlxCl(OH5) *xH20

Primary coagulant (used when pH, or temp doesnt suit alum). Same mechanism

lower sludge volume, easier pH, temp control, more expensive than alum

Ferric Salts: Uses, considerations

FeCl3 (ferric chloride), Fe2(SO4)3 (ferric sulfate)

Primary coagulant: same mechanism as alum. Specifically good for colored water / super turbid water treatment (humic/fulvic acid and turbidity removal)

pH range is wide: 4-9. HIGHLY CORROSIVE, STAINS EVERYTHING IT TOUCHES, lowers pH. Denser, darker floc than alum

Polyelectrolytes: Uses, types, considerations

Coagulant/flocculation aids, therefore helps filter performance and sludge density

Cationic: primary coagulant or to reduse metal coag dose

Anionic / nonionic: flocculant aid.

Can interfere with disinfection dose, cause it adds demand.

Activated Silica: Formula, uses, considerations

Na2SiO3. Activated with acid or CO2

Coagulant aid: extends, strengthens alum floc, esp. at low temps/low turbidity conditions.

must be freshly prepared on side. short shelf life after activation. Largely replaced by polymers

Sodium Hypochlorite: formula, use, considerations

NaOCl

Primary disinfectant. 5-15% chlorine

raises pH slightly, corrosive

can be generated on site.

Calcium Hypochlorite: formula, name, uses, considerations

Ca(ClO)2 / granular chlorine

disinfection: used at smaller systems, for superchlorination, and for disinfecting new mains/tanks

65-70% chlorine: fire / explosion risk.

Moisture causes decomposition and heat generation

Degrades over time.

Must dissolve before feeding.

Cl2 gas: misc facts

historically most common primary disinfectant.

2.5X heavier than air.

Toxic. IDLH (dangerous life health) & 10ppm

stored as pressurized liquified gas in 100lb / 150lb / 1 ton containers.

Vacuum operated systems safer than pressure fed.

Store upright, away from heat, ammonia, organics.

Leak detection: ammonia wand produces white cloud at leak point

Chloramines: misc notes

NH2Cl (monochloramine: primary. Also di- and trichloramines.

secondary disinfectant: distribution system residual maintenance.

fewer DBPs than free chlorine: used in systems with DBP issues or long distribution RT.

harmful to dialysis patients, fish/aquatic life.

di-or trichloramines lead to medicinal taste. Keep pH >7 to avoid.

ozone: misc notes

O3.

wildly powerful oxidant/disinfector. great against crypto, giardia, DBP precursor destruction.

no residual! Must be generated on site

can form bromate

expensive.

Lime: chemical, uses, considerations

CaO or Ca(OH2)

lime softening: precipitates Ca Carbonate and Mg hydroxide to reduce hardness.

Raises pH, alkalinity

High sludge volume.pH sometimes needs to be adjusted after.

Soda Ash: formula, uses, considerations

Na2CO3

raises pH, alkalinity (pH correction, corrosion control/stabilization.). softens/reduces calcium hardness when used with lime.

less aggressive pH increase than lime or caustic, safer to handle.

Caustic Soda: formula, uses, considerations

NaOH / sodium hydroxide

raises pH: corrosion control, etc. Good for large, precise pH increase.

highly caustic, exothermic

liquid freezes at 54F.

compatible with most metals (not aluminum, it dissolves aluminum pipes)

Fluoride compounds misc notes

fluorosilicic acid (most common, liquid) / sodium fluorosilicate (dry) / Sodium Fluoride (dry)

Target: .7mg/L

Polyphosphates & orthophosphate: uses, considerations

Poly: Fe, Mn sequestration.

Ortho: corrosion control: forms insoluble Pb/Cu phosphate layer on pipes. Takes weeks to months to form layer. needs pH >7

SWTR: Core requirements

3-log giardia removal/inactivation, 4-log for viruses.

finished turbidity <0.3NTU in 95% samples. Cant exceed 1NTU

minimum Cl2 residual set at 0.2mg/L both entering system and throughout.

C*T requirements set

SWTR Add-Ons

IESWTR / LT1: focuses on cryptosporidium (protozoan parasite) via NTU standards, sanitary surveys.

LT2: requires enhanced protectino based on found levels.

individual filter monitoring for NTU required.

DBPRs

set MCLs for DBPs, bromate, chlorite, chlorine, clO2, chloramines

DBPs evaluated as LRAA

Misc DBP notes: HAAs form faster. Bromate only when ozone used in bromide containing source water.

LCR

set action levels for Pb, Cu.

if AL exceeded, must optimize corrosion control, conduct public education, replace lead service lines, increase monitoring.

sample collection: first draw 1L after >6hrs stagnation

TCR

Requires: routine monitoring based on system size, no more than 5% montly samples can be TC positive

any E. Coli positive is acute violation, T1 public notification (24 hrs)

TC positive sample must be repeated within 24 hrs.

GWR

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