LOKESH SAINI

Mtech (Final), Env. Engg.

PURE WATER FROM RO SYSTEM

DOES ONLY

?

INPUT/OUTPUT

2/12

R.O. SYSTEM

SEAWATER

WASTEWATER

PERMEATE

RETEN

TATE

Surface water

8%

Waste water

6%

Brackish Water

19%

Sea Water67%

[27]

Type of feed in RO plantsUsed in world

CHALLANGES

1. FOULING

2. ELECTRICITY ASDRIVING SOURCE

3. BORON REMOVAL 4. FLOURIDE

REMOVAL

5. BRINE DISPOSAL

6. SOLID WASTE

7. HEALTHISSUES

8. ENVIRONMENT ISSUES

3/12

BRINE WASTE DISPOSAL4/12

•Reverse osmosis concentrate (ROC) or brine is the byproduct of ROprocess .•30-80% volume of RO feed.•1.2-1.7 times higher in concentration than feed .

•ROC disposal facility – 15% add. Cost.

•Affects ecology of receiving body e.g. ocean, stream & ground water. •Causes death to aqua species.

Why Challenge??

5/12

CHEMICALS, MEMBRANE CLEANING & IT’sDISCHARGE WITH REJECT

CLEANINGPhysical Cleaning

Back Washing

Air Scouring

Chemicals RemovesAlkali-Caustic Soda, pH11-12

Org. Fouling

Oxidative-NaOCl, H₂O₂, KMnO₄

Bio. Fouling

Acid- H₂SO₄, HCL, pH 2-3

Inorganic Fouling

[1],[17],[21]

ChemicalCleaning

[21]

•World RO desalination capacity is 65million m³/day.•@50%; Reject 32.5million m³/day.

Chemicals used in RO process :- coagulants, Acids, antiscalants, antisurfactants, disinfectants, dechlorinating agents

Once a Day

SOLUTIONS USUALLY ADOPTED6/12

•Treat brine by ion exchange, charge adsorption & multistage RO [1],[8].

Disposal Option

Method Benefits

Surface Fresh water, streams, oceans

Can accommodate largevolumes

Sewer Front & end of STP

Uses existinginfrastructure Lowers theBOD of the resultingeffluent.

Land Spray irrigation, infiltration trend, percolation ponds

No marine impactexpected

Deep well Non DW aquifers Possible commercial saltexploitation Lowtechnological andmanaging efforts

Evaporation Pond

Vaporize brine Can be used to irrigate salttolerant species, No marineimpact expected

ZLD Solidify Liquid in salt

Can commercially exploitconcentrate No marineimpact expected

[37]

•500 plants, under CSR, by

industries.(1kl-3kl/hr)

•2000 plants, by unorganized private

agencies(0.25kl-3kl/hr)

•3000 plants, under NRDWP, by GoR

(0.5kl-2kl/hr).

CASE STUDY IN RAJASTHAN•Performance study of community sized RO units in Jaipur &

Barmer, Rajasthan

•8 nos of plants capacity in Jaipur, Capacity 1000l/hr & 12 plants capacity 1000-3000l/hr.

7/12

RO waste water in Life CycleBrine/chemical

discharge to

environment

Plants located near Jaipur (Vidhani & Kalwara)

Avg. hrs of

operation

Unit discharge

(m³/hr or (ml/Yr)

Total

discharge

in its life

Disposal option

adopted

Brine Discharge

m³

6 900 m³/hr 59130 m³ Solar/ drain

Antiscalant

Polyacrylates

(ml/yr)

- - - Not used

pH Adjuster - - - Not used

Chemicals for

cleaning (ml/Yr)

NaOH

HCl

Na₄EDTA

2ml/yr

4ml/yr

2.4lt/yr

60ml

120ml

72lt

Solar/ drain

8/12

Situation of ground water in State(Report on dynamic ground water resources of Rajasthan, CGWD report-2009)

•Total Blocks-239

•Over-exploite-166

•Critical-25

•Semi critical-16•Safe-31

9/12

EXISTING DISPOSAL WAY OF REJECT

0

1000

2000

3000

4000

5000

6000

7000

Ju

n-1

6

Ju

l-1

6

Au

g-1

6

Sep

-16

Oct-

16

Kalwara Raw

Kalwara Filter

Kalwara ROC

TDS vs time at Kalwara

** Salt concentration in GW increased

because operator discharged ROC into an

abandoned tube well in the campus itself.

TD

S

DrawlDisposal

mg

/lt

Reject to drain

At Kalwara, Reject in drain At Barmer, Reject in solar pit

10/12

DRAWBACKS IN

EXISTING OPTIONS

• May further deteriorate in G.W.

quality.

• Increase load on plant, maintenance

cost increases.

• Risky for human &

strayed animals.

POSSIBLE

REMIDIES

• Use RO reject in school toilets flushing.

• Construction, Non RCC work e.g road work & Curing

FUTURE RESEARCH

ISSUES

• NF RO FW(90%)

• VMD R

• Improve recoveryratio, by optimizingthe antiscalant:

upto 85%.

SOLUTIONS & ITS

ANALYSIS

11/12

THANKS & WITH AIM TO PRODUCE SUFFICIENT AMOUNTOF USABLE (POTABLE) WATER IN A

SUSTAINABLE MANNER, WHICH IS ONE OF THE MOSTIMMEDIATE CHALLENGE FORHUMAN SOCIETY.

12/12