WASTEWATER TRAININGMAY 10TH, 2018

POOP EMOJI DISCOVERY

TODAY’S GOALS• Educate

• Save time/money• Reduce headaches• Maintain compliance

INDUSTRIAL WASTEWATER 101

• pH adjustment• Coagulation

• Flocculation• Types of treatment

• Treatment methods

• Dewatering equipment

TOPICS

INDUSTRIAL WASTEWATER 101 PH ADJUSTMENT

INDUSTRIAL WASTEWATER 101 pH ADJUSTMENT

In chemistry, pH is a numeric scale used to specifythe acidity or basicity of an aqueous solution. It isapproximately the negative of the base 10 logarithm ofthe molar concentration, measured in unitsof moles per liter, of hydrogen ions. More precisely it isthe negative of the base 10 logarithm of the activity ofthe hydrogen ion.[1] Solutions with a pH less than 7 areacidic and solutions with a pH greater than 7are basic. Pure water is neutral, at pH 7 (25 °C), beingneither an acid nor a base. Contrary to popular belief,the pH value can be less than 0 or greater than 14 forvery strong acids and bases respectively.[2] (SOURCE

WIKIPEDIA)

What does pH stand for?

Potential of Hydrogen

INDUSTRIAL WASTEWATER 101pH ADJUSTMENT

8

.

INDUSTRIAL WASTEWATER 101 pH ADJUSTMENT

INDUSTRIAL WASTEWATER 101pH ADJUSTMENT

pH Neutralization Reagents

• Sulfuric Acid

• Hydrochloric acid (muriatic)

• Calcium hydroxide (lime)

• Magnesium hydroxide

• Sodium hydroxide (caustic)

• Sodium carbonate (soda Ash)

INDUSTRIAL WASTEWATER 101 COAGULANTS

COAGULATION

Stable colloid

Most solids suspended in water possess a negative charge; they consequently repel each other. This repulsion prevents agglomerating, causing them to remain in suspension.

COAGULATION

Coagulation destabilizes the particles’ charges. Coagulants with charges opposite to those of the suspended solids are added to to neutralize the negative charges non-settable solids

Unstable colloid++++

+

+++

+

++ ++

++++

++

+ ++ + +

COAGULATION

Over-mixing does not affect coagulation.

Insufficient mixing will leave this step incomplete.

Proper contact time in the rapid-mix chamber is typically 1 to 3 minutes.

Pinfloc Formation +

+++

+

++ ++

+ ++ + +

++++

++

COAGULATION

With the charges neutralized, the small-suspended particles are capable of sticking together forming microflocs.

A high-energy, rapid-mix is necessary to properly disperse the coagulant and promote particle collisions needed to form microflocs.

Pinfloc Formation +

+++

+

++ ++

+ ++ + +

++++

++

Colloidal Suspension

Charge Neutralization

Liquid SolidSeparation

INDUSTRIAL WASTEWATER 101 COAGULANTS

TYPES OF COAGULANTS

ORGANIC

• Polyamine• Polydadmac• Melamine formaldehyde resins• Dicyandiamide resins• Aminomethylated tannins• Polyvinylamine

INORGANIC

• Iron (Ferric/Ferrous chloride & sulfate)

• Aluminum (Aluminum sulfate & chloride)

• Aluminum chloride & sulfate

• Poly-aluminum chloride (PAC) (polymer)

• Aluminum chlorohydrate (ACH) (polymer)

• Clay

INORGANIC COAGULANTS

ADVANTAGES

• Wide range of applications

• Low cost per pound

• Can be fed neat

• Readily available

DISADVANTAGES

• High dosage

• High sludge volume

• Affect ph and alkalinity

• Metal impurities

ORGANIC COAGULANTS

ADVANTAGES

• Low dosage• Low sludge volume• No impact on ph and alkalinity

DISADVANTAGES

• Higher cost per pound• May need to be diluted before

feeding

INORGANIC/ORGANIC COAGULANTS

• All of the advantages and few disadvantages.

• ADVANTAGES

Coagulant Dosing:

Ø Rapid mixing of coagulants is required.Ø Typical coagulant dose rates are from 500 to

15000 mg/l.Ø Significant overdose of coagulant can cause

cationic reversion. Ø Coagulants cannot be mixed too long.

INDUSTRIAL WASTEWATER 101COAGULANTS

INDUSTRIAL WASTEWATER 101 COAGULANTS

• The end game of coagulation is charge neutralization. This is known as the isoelectric point.

CATIONS(+) = ANIONS(-)

INDUSTRIAL WASTEWATER 101 FLOCCULANTS

GET THE TERMINOLOGY RIGHT

FLCOCCULANTS (a.k.a. POLYMERS):

A substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together

Often used as a general term to describe flocculants

Organic coagulants are polymers

POLYMERS

MONOMER MONOMER MONOMER MONOMER

POLYMERS

LINEAR POLYMERS BRANCHED POLYMERS

TYPES OF FLOCCULANTS

FORMS

• Emulsions

• Dry/powders

• Solutions• Dry polymer in water (about 2%)

CHARGE TYPE

• Anionic (-)

• Cationic (+)

• Nonionic (neutral)

STRUCTURE

• Linear

• Branched

• Linear• Branched

• "Crosslinked"

FLOCCULANT CHARACTERISTICS

• Molecular weight: the weight of all of the elements in a particular molecule.• Higher is not better. Need to test to determine best fit for application.

• Charge density: frequency of positive or negative charge.

• Structure: cross linking different parts of the molecule• Makes a more stable floc will hold up in higher shear applications

• Centrifuge

• Screw press

FLOCCULATION

• Increases the particle size from submicroscopic microfloc to visible suspended particles.

• The microflocs are brought into contact with each other through the process of slow mixing. Collisions of the microfloc particles cause them to bond to produce larger, visible flocs.

FLOCCULATION

Unstable colloid

Floc formation

Polymer bridges++ + +

+ + + +++

+

+

+ +

+

++

+

+

+

+

+

+

+

++

+ ++ + + ++

+

+ + +

+ + + + +

++

+

Colloidal Suspension

Charge Neutralization

Liquid SolidSeparation

INDUSTRIAL WASTEWATER 101 FLOCCULANTS

Flocculation

INDUSTRIAL WASTEWATER 101 FLOCCULANTS

Polymer Preparation:

INDUSTRIAL WASTEWATER 101FLOCCULANTS

Polymer Must Be Prepared Properly To Provide Optimal Process Performance

ØThe optimum dilute concentration must be determined

- Typically 0.1 to 0.5% ActiveØThe proper mixing energy is

required to make-down polymer.ØThe proper aging time is important. Ø - Typically 20 to 30 Minutes

Polymer Dosing:

Ø The optimum mixing time (30 sec. – 90 sec.) should be determined by floc size and mixing time may vary from batch to batch.

Ø Typically a polymer dose of 20 to 30 mg/l is sufficient.

Ø Significant overdose of polymer can plug filter clothes.

Ø Be careful not to shear the polymer by mixing it too long.

INDUSTRIAL WASTEWATER 101FLOCCULANTS

FLOCCULANTS - IMPORTANCE OF PH

• Over 7 – increasingly alkaline – anionic flocculants work best.

• Below 7 – increasingly acidic – cationic flocculants work best.

• For every application there will be an optimum pH range.

• Samples may need pH adjustment

• There are pH levels that are too high or low for a product to work

BEST PRACTICES – FLOCCULANTS• Blending & feeding emulsions

• Strainer between storage container and feed system

• Emulsion must be added to the water

• Very high shear must take place at the point of contact of water and

flocculant

• Water must be as soft as possible

• Water temperature be below 86°F (30°C)

• Optimal final concentration 0.2 – 0.8%

• 15-30 minutes of aging provides best performance

• High viscosity diaphragm pumps or peristaltic are best. Peristaltic must use

tygothane (or equivalent) tubing.

INDUSTRIAL WASTEWATER 101 TREATMENT TYPES

TYPICAL BATCH TREATMENT PROCESS

• pH adjustment• Addition of coagulant• Addition of flocculant• Flotation sedimentation of sludge• Discharge of water• Processing of sludge

INDUSTRIAL WASTEWATER 101INORGANIC TREATMENT

TYPICAL BATCH TREATMENT PROCESS• Reaction tanks also serve as clarifier• Solids settle and sludge is thickened• Effluent is decanted, discharged or sent to 20 treatment• Allows for maximum control of effluent quality

10 Treatment PrecipitantCoagulantFlocculant

pH AdjustCoagulantFlocculant

City EffluentCity Effluent

SludgeSludge

20 Treatment

Decant

TYPICAL BATCH TREATMENT PROCESS

Water

Solids

INDUSTRIAL WASTEWATER 101INORGANIC TREATMENT

TYPICAL BATCH TREATMENT PROCESS

• pH adjustment• Addition of Emulsion breaker• Flotation of sludge• Discharge of water• Further Processing of oil

INDUSTRIAL WASTEWATER 101ORGANIC TREATMENT

TYPICAL ORGANIC TREATMENT PROCESS

• Reaction tanks also serve as clarifiers• Effluent is decanted off bottom• Oil floats and is further processed• Allows for maximum control of effluent quality

10 TreatmentPrecipitant CoagulantFlocculant

Emulsion Breaker

Oil Effluent

Effluent

20 Treatment

SludgeEffluent

TYPICAL ORGANIC TREATMENT PROCESS

Oil

Water

Rag

Solids

INDUSTRIAL WASTEWATER 101ORGANIC TREATMENT

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

45

.BATCH TREATMENT

In a batch treatment system, a volume of wastewater is gathered, treated by chemical/physical/biological means, and discharged.

In applications where TSS and dosage concentrations are high and daily flows are less than 8,000 GPD batch treatment is recommended.

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

46

.CONTINUOUS FLOW – SEDIMENTATIONSedimentation is a physical water treatment processusing gravity to remove suspended solids fromwater.[1] Solid particles entrained by the turbulence ofmoving water may be removed naturally bysedimentation in the still water of lakes andoceans. Settling basins are ponds constructed for thepurpose of removing entrained solids bysedimentation.[2] Clarifiers are tanks built withmechanical means for continuous removal of solidsbeing deposited by sedimentation. Source Wikipedia

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

47

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

CONTINUOUS FLOW – FLOTATIONDissolved air Flotation (DAF) is often used. Aftercoagulation and flocculation processes, water flowsto DAF tanks where air diffusers on the tank bottomcreate fine bubbles that attach to floc resulting in afloating mass of concentrated floc. The floating flocblanket is removed from the surface and clarifiedwater is withdrawn from the bottom. Source Wikipedia

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

ACTIVATED SLUDGE

The activated sludge process is a type of wastewater treatment for treating sewage or industrial wastewaters

using aerobic process and a biological floc composed of

bacteria and protozoa. SOURCE WIKIPEDIA

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

Aerobic treatment – “with oxygen’• Low/medium soluble

bod/cod applications• No methane gas produced

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

Anaerobic treatment “without oxygen” . • High soluble BOD/COD applications.• Produce methane biogas.

INDUSTRIAL WASTEWATER 101 TREATMENT METHODS

1. At pH of 3.5 are there more h+ or oh- ions present In wastewater?

2. Are coagulants anionic or cationic?

3. Does and anaerobic digester use oxygen?

4. Name one method of liquid/solid separation?

QUIZ