This document discusses corrosion in industrial water systems. It outlines several problems caused by corrosion, including scaling, corrosion of equipment, microbiological corrosion, disposal of wastewater, and biofouling. It then describes various corrosion control techniques like coatings, cathodic protection, material selection, and corrosion inhibitors. Finally, it briefly discusses cooling water systems and the types of open and closed recirculating systems.

1. INDUSTRIAL WATER
CORROSION
PRESENTED BY
YASER SALEEM SIDDIQUI
M.TECH – CIVIL(ENVIRONMENTAL ENGG.)
3RD SEMESTER

2. WHAT IS CORROSION?
• CORROSION MAY BE DEFINED AS THE GRADUAL DESTRUCTION OF MATERIALS
WHICH ARE USUALLY METALS DUE TO THEIR CONTACT WITH THE SURROUNDING
ENVIRONMENT.
• IT IS BASICALLY THE CHEMICAL OR ELECTROCHEMICAL DESTRUCTION OF METAL
WITH ENVIRONMENT.
• CORROSION DEGRADES THE METALS THEREBY REDUCING STRENGTH AND
OTHER PHYSICAL AND CHEMICAL PROPERTIES OF METAL.

3. SIGNIFICANCE OF THIS PRESENTATION
• AS FAR AS THE TOPIC OF THIS PRESENTATION IS CONCERNED,WE SHALL DISCUSS
THE PROBLEMS DUE TO CORROSION IN INDUSTRIAL WATER.
• CORROSION HAS VARIOUS EFFECTS ON INDUSTRIAL WATER SUPPLIES.
• THE MAIN PROBLEMS IN INDUSTRIAL WATER SYSTEMS ARE;
1.SCALING
2.CORROSION
3.MICROBIOLOGICAL CORROSION
4.DISPOSAL OF RESIDUAL WASTEWATER
5.BIOFOULING

4. SCALING:
• SCALING OCCURS WHEN THE TEMPERATURE AS WELL AS THE
CHEMICAL CONDITIONS ARE SUCH THAT THE DISSOLVED
MINERAL SALTS WHICH ARE PRESENT IN WATER PRECIPITATE
AND FORM SOLID DEPOSITS.
• SCALING REDUCES THE HEAT EXCHANGE EFFICIENCY AS IT
BECOMES AN INSULATING MEDIUM.
• SCALING CAUSES WASTAGE OF ENERGY.
• SCALING IS RESPONSIBLE FOR INCREASE IN PIPE
WIDTH(DIAMETER),WHICH INCREASES THE LOAD ON THE PUMP.

5. CORROSION:
• CORROSION OCCURS AS A RESULT OF OXIDATION OF
PARENTAL METALS SUCH AS IRON RUSTS.
• THE INTEGRITY OF THE VARIOUS PLANT EQUIPMENTS
IS THEN GRADUALLY COMPROMISED.
• CORROSION CAN BE RESPONSIBLE FOR CAUSING
LEAKS.
• LEAKAGES IN PRESSURISED SYSTEMS MAY BE VERY
DANGEROUS FOR THE PLANT WORKERS.

7. MICROBIOLOGICAL CORROSION:
• UNTREATED COOLING WATER IS WARM AND MAY CONTAIN
ORGANIC NUTRIENTS.
• MICROBES GENERALLY THRIVE IN SUCH WATERS AS THE WET
COOLING TOWERS ARE GOOD AIR SCRUBBERS.
• DUSTS, FUNGAL SPORES, GRASS,FLIES ETC. GET COLLECTED
IN THE WATER AND THEREBY FORM OF ‘MICROBIAL SOUP’ IF
THEY ARE NOT WELL TREATED WITH BIOCIDES.
• DEADLY LEGIONNAIRES' DISEASE IS ALSO CAUSED DUE TO
THE PROBLEM OF UNTREATED COOLING WATERS.

8. DISPOSAL OF RESIDUAL INDUSTRIAL
WASTEWATERS:
• THIS IS ONE OF THE MOST DIFFICULT CHALLENGES WHICH HAS TO BE TACKLED.
• THIS IS DIFFICULT AS WELL AS COSTLY.
• MANY CHEMICAL, PETROCHEMICAL REFINERIES AND PLANTS HAVE AN ARRANGEMENT OF ONSITE
DISPOSAL OF THEIR RESIDUAL WASTEWATERS.
• THE POLLUTANT CONCENTRATION LEVELS OR PERMISSIBLE LIMITS SHALL COMPLY WITH THE
LOCAL/NATIONAL REGULATIONS AS FRAMED BY THE GOVERNMENT SO AS TO DISPOSE THE
WASTEWATER INTO COMMUNITY TREATMENT PLANTS, RIVERS, LAKES OR SEAS.

9. BIOFOULING:
• IT IS A PHENOMENON WHERE WATER SURFACES IN CONTACT
WITH WATER ARE COLONISED BY MICROORGANISIMS.
• CORROSION ASSOCIATED WITH MICROORGANISIMS HAS BEEN
RECOGNISED FOR OVER 50 YEARS.
• BIOFOULING IS A CRITICAL ISSUE IN MEMBRANE WATER AS WELL
AS WASTEWATER TREATMENT.
• BIOFOULING GREATELY COMPROMISES THE EFFICIENCY OF
TREATMENT PROCESSES.
• MEMBRANE FOULING IS A MAJOR PROBLEM ENCOUNTERED IN
MEMBRANE FILTERATION PROCESSES.
• IT IS A MAJOR FACTOR IN DETERMINING THE PRACTICAL
APPLICATION IN WATER AND WASTEWATER TREATMENT AND
DESALINATION IN TERMS OF TECHNOLOGY AND ECONOMICS.

10. ADVERSE EFFECTS OF BIOFOULING:
• MEMBRANE FLUX DECLINE DUE TO FORMATION OF LOW PERMEABILITY BIOFILM
ON THE MEMBRANE SURFACE.
• INCREASED DIFFERENTIAL PRESSURE AND FEED PRESSURE BEING NEEDED TO
MAINTAIN THE SAME PRODUCTION RATE DUE TO BIOFILM RESISTANCE.
• MEMBRANE BIODEGRADATION CAUSED BYACIDIC BY-PRODUCTS WHICH ARE
CONCENTRATED AT THE MEMBRANE SURFACE.

11. CORROSION CONTROL TECHNIQUES:
• BASICALLY THERE ARE FOUR METHODS FOR CORROSION CONTROL
1.COATINGS AND LININGS.
2.CATHODIC PROTECTION(CP)
3.MATERIALS SELECTION.
4.CORROSION INHIBITORS.

12. • COATINGS AND LININGS ARE OFTEN APPLIED IN CONJUNCTION WITH CATHODIC PROTECTION
SYSTEMS IN ORDER TO PROVIDE A COST-EFFECTIVE PROTECTION SYSTEM FOR A STRUCTURE.
• CATHODIC PROTECTION (CP) IS A TECHNIQUE THAT USES DIRECT ELECTRICAL CURRENT IN
ORDER TO COUNTERACT THE NORMAL EXTERNAL CORROSION OF A STRUCTURE, THAT
CONTAINS METAL SUCH AS AN UNDERGROUND PETROLEUM STORAGE TANK OR NATURAL GAS
PIPELINE.
• MATERIAL SELECTION REFERS TO THE SELECTION AND USE OF CORROSION RESISTANT
MATERIALS SUCH AS STAINLESS STEEL, PLASTICS AND SPECIAL ALLOYS TO INCREASE THE LIFE
SPAN OF A STRUCTURE.
• CORROSION INHIBITORS ARE THE SUBSTANCES THAT WHEN ADDED TO A PARTICULAR
ENVIRONMENT,DECREASE THE RATE OF ATTACK OF ENVIRONMENT ON THE MATERIAL SUCH AS
METAL.THEY CAN HELP TO INCREASE THE LIFE SPAN OF A METAL USED AS PIPES OR IN ANY
PART OF A STRUCTURE.

13. EPOXY COATING

14. SOME COMMONLY USED CORROSION
INHIBITORS FOR VARIOUS PURPOSES

15. • THESE CORROSION INHIBITORS INCLUDE
1. ANODIC INHIBITORS
2. CATHODIC INHIBITORS
3. BOTH (FILMING AMINES, PHOSPHATES)
SCALE/DEPOSIT CONTROLLERS:
• CONGLOMERATION OF MANY CONSTITUENTS THAT CAN RANGE FROM SETTLED SOLT FROM
AIR BORNE DUST BLOWN INTO THE COOLING TOWER TO PRECIPITATE.
1.PHOSPHATES
2.PHOSPHONO-CARBOXYLATES
3.ORGANIC ACIDS
4.POLYMERS

16. COOLING WATER SYSTEMS:
• A COOLING SYSTEM IN WHICH WATER IS USED AS A COOLING AGENT TO
PROVIDE COOLING ACTION AND THEREBY LOWER THE TEMPERATURE.
TYPES OF COOLING WATER SYSTEMS:
• THE WATER CAN BE DISCHARGED AT THE INCREASED TEMPERATURE INTO A
RECEIVING BODY ONCE THROUGH COOLING SYSTEM OR IT CAN BE COOLED AND
REUSED(RECIRCULATING COOLING SYSTEM)
• THERE ARE TWO TYPES OF COOLING SYSTEMS NAMELY;
1. OPEN SYSTEMS
2. CLOSED RECIRCULATING SYSTEMS

17. • IN OPEN SYSTEMS COOLING IS ACHIEVED THROUGH EVAPORATION OF A FRACTION
OF THE WATER. EVAPORATION RESULTS IN LOSS OF PURE WATER FROM THE SYSTEM
AND A CONCENTRATION OF REMAINING DISSOLVED. WATER MUST BE REMOVED OR
BLOWN DOWN IN ORDER TO CONTROL THIS CONCENTRATION AND FRESH WATER
MUST BE ADDED TO REPLENISH THE SYSTEM.
• IN CLOSED RECIRCULATING SYSTEMS, THERE IS A COOLING SYSTEM WITHIN A
COOLING SYSTEM. THE WATER CONTAINING HEAT TRANSFERRED FROM THE
PROCESS IS COOLED FOR REUSE BYMEANS OF AN EXCHANGE WITH ANOTHER FLUID.
WATER LOSSES ARE USUALLY SMALL.