• Author / Uploaded
• Vineet Chaudhary

Citation preview

OPERATION & MAINTENANCE MANUAL OF SEDICELL

KROFTA ENGINEERING LIMITED Durga Bhavan, A-68, FIEE Complex, Okhla Industrial Area, Phase – II, New Delhi – 110 020 Email: [email protected] Web site: www.kroftaengineering.com

Viva Boards Pvt. Ltd.

Operation & Maintenance Manual For

KROFTA SEDICELL SDC-22 Of Viva Board Pvt. Ltd. Vill: & Mdl: Renjal, Dist. Nizamabad, A.P.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 2

Viva Boards Pvt. Ltd.

TABLE OF CONTENTS S. NO.

TITLE

PAGE. NO.

1.

Data Sheet

2.

Sedicell General Description

3.

Sedicell Basic Operating Principles

7

4.

Safety Requirements

8

5.

Sedicell-Maintenance Schedule

9-10

6.

Sedicell Operational & troubleshooting Procedures

11-15

7.

Air Dissolving Tube System

16-19

8.

Annexure A. Spare Parts List

O&M Manual for Krofta Sedicell (SDC-22)

4 5-6

21

Page | 3

Viva Boards Pvt. Ltd.

DATASHEET CUSTOMER DATASHEET: Sedicell Size: SDC 22 Flow Capacity: 145 m3/h Purchased by: Viva Boards Pvt. Ltd. Date order entered: 27.04.2012 Purchase Order Number: DIMENSIONS AND CONSTRUCTION DETAILS: Dimensions: Diameter: 6700 mm ……………………………………………… Height: 3300 mm………………………………………………… FEED PUMP: Flow: 145 m3/h………………………Pressure: 12m Head………………… HIGH PRESSURE PUMP: Flow: 48 m3/hr……………………….Pressure: 65 m Head………………. AIR COMPRESSER: Capacity: 7.5m3/hr ……………………Pressure: 6.5kg/cm2…………………. VARIABLE SPEED GEARMOTOR: kW: 1.1…………………………Speed : 3.8 – 23 rpm……………….

O&M Manual for Krofta Sedicell (SDC-22)

Page | 4

Viva Boards Pvt. Ltd.

Chapter I SEDICELL - GENERAL DESCRIPTION a.

TANK COMPONENTS: (Non-Rotating Parts)

The SEDICELL is made up of tank walls, normally in Mild Steel or stainless steel, tank floor, of concrete, fixed central part, usually mild steel/stainless steel, rotating carriage (which supports the scoop and bottom scraper), clarified take-off ring and level control. A sump well in the tank floor is provided to collect sediment pushed in off the floor by a rotating bottom scraper. A purge valve is standard with automatic timed opening for sediment removal. A window located on the tank wall is adjacent to the platform for visual verification of floated sludge thickness. The outer tank rim and central fixed part support the rotating carriage drive and scoop. The Fixed Central Inlet, standard in MS/SS, supports the inner support and centring mechanism and receives floated sludge drained from the Spiral Scoop. b.

LEVEL CONTROL:

Level control is by means of a circular Overflow Weir, which is attached to the outside of the Tank Wall. The height of the weir is adjusted by the use of a hand-wheel. It maintains a precise water level in the unit, critical for controlling the scooping depth and therefore the sludge removal rate of the Spiral Scoop, and hence sludge consistency c.

CENTRAL FIXED PART:

The central fixed part is essentially a small flocculation zone. The feed enters the bottom of the flocculation zone and slowly rises up and overflows outwards. This part is also a central support and centring device for the moving carriage. d.

CARRIAGE FRAME: (Scoop Support)

The Carriage Frame carries the scoop for sludge removal from the surface of the liquid in the tank. It is driven around the tank by a motor-gearbox. This drive wheel runs on the tank rim, as do the other external support wheels. The centre of the carriage frame is supported and centred by a thrust bearing in the centre. The carriage also carries the floor and wall scrapers, which scrape any settled materials into the floor sumps. The drive wheel shaft is supported at each end by pillow block or flange bearings.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 5

Viva Boards Pvt. Ltd.

e.

SPIRAL SCOOP:

The KROFTA Spiral Scoop, standard in mild steel/stainless steel, removes floated material from the top surface of the water for discharge into the Fixed Central Part Tank for removal from the unit. It is supported on the outer end by a bearing mounted to the Carriage Frame. The inner end of the scoop is supported by two inner support wheels. The Spiral Scoop is driven by drive wheel gearbox motor through a chain-sprocket arrangement. Primary control of the sludge removal rate is by water level adjustment. This must be set to ensure the scoop is removing sludge only - not water. Fine adjustment of sludge removal rate is carried out by the use of the external variable speed motor controller (inverter). f.

FLOOR SUMPS

There are two sumps built into the floor of the unit. Any heavy materials that enter the SEDICELL will fall to the floor where they are scraped around until they drop into one of the sumps. From there they will be discharged through a pneumatic valve, which is controlled by a timer. g.

AIR DISSOLVING TUBE: (ADT)

The ADT is provided to aerate clarified water, which will in turn provide air bubbles to float the solids to the surface of the SEDICELL for removal. Water passes down the ADT in a spiral path passing the porous plastic VYON panels as it goes. Air is forced through the many tiny pores in the VYON and mixes with the water and dissolves in it. Because of the large surface area in contact with the water a high saturation is achieved.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 6

Viva Boards Pvt. Ltd.

Chapter II SEDICELL - BASIC OPERATING PRINCIPLES The SEDICELL removes solids by means of dissolved air flotation and sedimentation simultaneously. The feed water enters the SEDICELL in the center and flows outwards to the outer walls. During this slow journey the solids float to the surface and are removed by the rotating scoop, this then leaves the clarified water to be removed by the Clarified Take-off ring which runs around the inside of the tank walls.

Heavy material drops to the tank floor where it is scraped into a sump(s) and hence discharged through an auto valve, which opens periodically on a timer.

Floatation of solids occurs because of air bubbles introduced into the feed water. Clarified water from the outlet of the SEDICELL is pumped under pressure through an Air Dissolving Tube where air under pressure is dissolved in the water. This air stays in solution as long as the water is at pressure. The pressure is released by a special GLOBE VALVE, just before this water is injected into the feed line. This pressure reduction causes the air to come out of solution and form millions of tiny air bubbles, which then attach themselves to the solid particles in the feed water. These bubbles cause the solids to float to the surface of the SEDICELL where they can be removed by the spiral scoop.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 7

Viva Boards Pvt. Ltd.

Chapter III SEDICELL - SAFETY REQUIREMENTS SEDICELL units are equipped with safety guards for operator protection from outside the unit. Larger SEDICELL units are equipped with walkways allowing limited operator access into the centre of the unit. For operator access to the SEDICELL walkway, wait until the walkway is in the best access position before stopping both the Carriage and Spiral Scoop motors. At no time should any adjustment, inspection or maintenance be undertaken on or in the SEDICELL unit without the entire unit being completely shutdown with the main power switch to electrical equipment shut off. It is required that a lock be put on the main power switch in the off position at times when personnel are working on or in the SEDICELL unit. The manufacturer, Krofta Engineering Ltd, New Delhi-India will not accept any responsibility for claims resulting from injuries caused by failure to follow the above guidelines.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 8

Viva Boards Pvt. Ltd.

Chapter IV SEDICELL - MAINTENANCE SCHEDULE 4.1

GENERAL:

SEDICELL units should receive a “walk around” visual inspection at least once weekly, a thorough item by item inspection monthly, and lubrication and adjustment on a three month schedule minimum with continuous operation, or on a six month schedule maximum with intermittent operation. 4.2

TANKS: (Non-Rotating Parts)

Paint wear and light rusting on the rim is allowable as it serves to improve traction of the drive wheel. The rim should be brushed or hosed off periodically and always be kept cleaned of dirt, grease and oil. Periodic touch-up painting of mild steel parts is recommended if sign of wear, chipping or rusting become apparent on the unit. Only routine cleaning is required for stainless steel. Windows should be cleaned regularly as required. 4.3

CARRIAGE FRAME: (Scoop Support)

Visual inspection of the carriage and equipment on the carriage should be done on a daily to weekly basis. Signs of wear or misalignment of wheels or other components should be looked for and corrected before any major damage is done. The carriage structure should be cleaned periodically to remove accumulated dust, dirt and grease, preferably during shutdown. The carriage wheels should be inspected monthly and the carriage wheel bearings should be lubricated on a three to six month schedule. Lubrication should be increased if sign of wear or moisture contamination are present. The gearboxes require periodic oil changes as detailed on the enclosed manufacturer’s literature. 4.4.

SPIRAL SCOOP:

Only routine cleaning is required for stainless steel. Support wheels/saddle and bearings are to follow the same schedule as for Carriage Frame components.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 9

Viva Boards Pvt. Ltd. 4.5.

LUBRICATION:

All wheels and bearing supports are to be lubricated with greased every week. REPLACEMENT OF AIR DISPERSION PANEL IN A.D.T: 1. Close feed valve to ADT and air line isolation valve. 2. Drain down ADT by opening drain valve and leave open. 3. Remove flanged end of tube. 4. Remove air line feeding dispersion panel and locking nut. 5. Remove two securing nuts from dispersion panel fixing bolts on outside of ADT. 6. Withdraw panel from within tube. 7. Remove securing bolts from around dispersion panel. 8. Fit new panel and drill through plastic part (6mm drill). Seal edges with sealant and refit nuts and bolts. 9. Fit new rubber sealing washers behind dispersion panel (3 off). 10. Replacement is reversal of removal.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 10

Viva Boards Pvt. Ltd.

Chapter V SEDICELL - OPERATING PROCEDURES 5.1

INITIAL START-UP PROCEDURES:

1.

Close all drain, sampling, automatic bottom purge and air inlet valves to the SEDICELL and AIR DISSOLVING TUBE.

2.

Start the drive motors for the carriage and scoop. Adjust the drive speed so that the SEDICELL carriage revolves approximately once every three minutes.

3.

Turn on the AIR DISSOLVING TUBE recycle pressure pump and air compressor. Adjust the air pressure regulator to 6 Bar. Adjust the air flow meter valves until the flow reading is correct. Note that the air pressure must always be around 1 bar higher than the water pressure to ensure air is forced into solution in the water. Each VYON panel requires a minimum of 30 lpm of air. If more than one Vyon panel is supplied by a single airflow meter (rotameter) this should be set so there is enough airflow to provide 30 lpm per panel.

4.

Start the chemical flocculent pumps.

5.

Turn on the raw water feed pump, or open inlet valve if gravity fed.

6.

Set the level control weir so that the Scoop is removing surface sludge.

5.2

ADJUSTMENT PROCEDURES DURING OPERATION:

1.

See AIR DISSOLVING TUBE operation instructions for flow and performance

2.

The water level in the SEDICELL should be adjusted for optimum floated sludge collection by the Spiral Scoop. Lowering the water level reduces sludge collection, allowing a thicker, dryer layer of sludge to form on the surface. Raising the level increases collection and reduces the sludge layer, and hence collected sludge consistency. It can take up to an hour after a level change before the sludge thickness reaches equilibrium. The sludge layer is too thick when it begins to break-up in pieces and/or settle out. Adjustment of the Spiral Scoop rotation speed is important for fine tuning the sludge removal rate after the water level is established.

3.

The settled sludge purge should be set depending on how much and at what rate settled material collects in the system. Typical purge valve time open duration would be 5 to 10 seconds or until clear water flows out. The interval between valve openings should initially be set between 15 minutes to one hour and then adjusted based on operating experience.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 11

Viva Boards Pvt. Ltd.

5.3

SHUT-DOWN PROCEDURES:

1.

Turn off the chemical pumps.

2.

Turn off the AIR DISSOLVING TUBE pressure pump before closing the isolation valve from compressor.

3.

Turn off power to Purge Valve Timer (if equipped) leaving air pressure on to maintain valve in closed position if water is to remain in the SEDICELL.

4.

Continue to operate the Spiral Scoop and Carriage drive until remaining sludge has been removed. Clean-up is easier if the SEDICELL is allowed to run after the process flow has stopped. Clarified water will recirculate and most of the solids will be flushed from the system.

5.

Valve and control settings previously established should not be changed.

6.

The water does not have to be drained out unless the shut-down is for a long period or complete wash-up is necessary.

7.

If the SEDICELL is drained, hose down all parts thoroughly as dried-on sludge can be very difficult to remove.

5.4

NORMAL START-UP AND OPERATION PROCEDURES:

1.

Follow the same sequence as for initial start-up except that previously established valve and control settings should be maintained unchanged.

2.

Check that the AIR DISSOLVING TUBE pressure is around 5 Bar and that the clarified water is clear. If not, follow the procedure in Part 5.5 (Trouble Shooting Procedures).

3.

If the SEDICELL is started up before process start-up, the SEDICELL will operate and continuously recirculate and clean the clarified water. This will help prevent solids build-up in the clarified water during start-up.

5.5

TROUBLE SHOOTING PROCEDURES: Poor water clarification in the SEDICELL can be a result of problems caused by solids overloading, poor flotation resulting from AIR DISSOLVING TUBE problems, or inadequate/improper chemical addition. A water sample taken from the inlet area of the SEDICELL, preferably in a graduated cylinder, provides many clues for diagnosing problems. The following are some common areas to check if there are clarification problems:

O&M Manual for Krofta Sedicell (SDC-22)

Page | 12

Viva Boards Pvt. Ltd.

5.5.1 SOLIDS OVERLOADING PROBLEMS: Overloading is a result of unusually heavy solids loads on the SEDICELL, as can occur at wash ups or at times of heavy solids loading from the process. Overloading can cause unclear water and in extreme cases physically clog parts of the system. The most effective solution is to simply decrease the solids loading if at all possible. If the overload clogs the system with sludge, the system will unclog itself when the overloads stops, unless the thick sludge is allowed to block the clarified water pipe. Overloads can sometimes be compensated for by adding more chemical. NOTE: Do not run the SEDICELL completely filled with heavy sludge. This can cause strain and possibly damage rotating parts. 5.5.2 CHEMICAL ADDITION PROBLEMS: NOTE: Chemical addition should not require day-to-day adjustment unless the feed quality or quantity varies. a. Not enough chemical; Symptoms include very small particles remaining in the clarified water, slow flotation, or thin floated sludge. Check the following items: i. ii. iii. iv.

Chemical pump or lines plugged? Out of chemical? Have pump settings been changed? If the concentration of solids in the incoming water has changed or there is some change in the ph, de-foamer addition etc., this may change the chemical demand requiring higher amounts.

b. Too much chemical: Symptoms of chemical overdosing include a very “greasy” sludge, a watery or “fat” sludge and very large particles in the water to which the air will not stick. (This could also indicate the presence of de-foamer in the system). A slippery or greasy feel in the clarified water can also indicate overdosing resulting in chemical carry-over into the clarified water. c. NOTE: All chemical adjustments should be made slowly, as changes can take from 3 to 20 minutes to take full effect. If the clean water is recycled, it can take hours for the system to reach equilibrium. 5.5.3 AERATED RECYCLE WATER ADDITION PROBLEMS: NOTE: See also AIR DISSOLVING TUBE SYSTEM for additional information. a. Too much “air” in system; Indicated by foaming or frothing at the SEDICELL water surface, excessive and large turbulent bubbles at the inlet, foamy sludge. Before changing settings, check the following: i. Dissolving tube air bleed-off plugged? (This can cause large bubbles in inlet). ii. Has air addition to the AIR DISSOLVING TUBE changed? iii. Is the feed pump pulling in air or cavitating? iv. Has detergent, caustic or other foaming agent been added to water? v. Solids in the feed water unusually low? O&M Manual for Krofta Sedicell (SDC-22)

Page | 13

Viva Boards Pvt. Ltd.

b. Not enough “air” in system; Indicated by watery sludge, sludge not floating or floating slowly, very “flat” appearance of inlet water. i. ii. iii. iv. v.

5.6

Is air line plugged or has air pressure dropped lower than pressure in dissolving tube? Is air pressure reduced, causing reduced air flow? Check for chemical problems such as defoamer in system, chemical overdose. Very reduced water flow caused by a plugged valve or cavitating of the feed pump may greatly reduce dissolving efficiency. Unusually high solids in the incoming water may also cause the above symptoms. This can sometime be corrected by increasing air addition.

TROUBLE SHOOTING PROCEDURES – MECHANICAL:

5.6.1 DRIVE WHEEL SLIPPING; Spinning or stalling of the Drive Wheel is usually a symptom of other problems in the system. If there is a heavy load on the system, the wheel should slip before any serious mechanical damage is done. Typical causes of slipping are: a. Check if the drive wheel is worn down or damaged. If so, that usually indicates the presence of other problems mentioned. (Normal tyre life is 1-2 years). b. Proper wheel alignment of the Drive Wheel and support wheels is important for wheel, life and to reduce rotation resistance. c. Excessive load of solids in the Clarifier. If the Clarifier is allowed to fill with floated sludge, the force required to move the rotating parts is much higher. The overload condition should be fixed by draining the sludge out and starting over again if possible or by raising the level and speeding up the Scoop. If the sludge is very thick, water dilution may be necessary at first. This kind of condition should be corrected as soon as possible to avoid damage of the rotating parts. d. Excessive settled sludge in the Clarifier. This usually is the result of non-function of the bottom purge or of some upset in the Clarifier which has caused excessive settling. The bottom purge should be operated frequently until the condition is cleared. A sample scraped from the bottom of the unit or taken from the bottom line can help identify this problem. e. Foam or polymer on edge. Excessive foaming can result from chemical problems in the process or improper air condition. Foam can carry a high load of flocculant polymer which is very slippery. This should be thoroughly washed off. f. Mechanical malfunction. The general cleanliness of the unit and the function of the wheels, should be checked thoroughly and operated with all mechanical clearances (especially of the outside edge) checked.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 14

Viva Boards Pvt. Ltd.

Chapter VI AIR DISSOLVING TUBE SYSTEM 6.1

GENERAL PRINCIPLES:

The KROFTA Flotation System removes solid impurities from the water by floating them to the surface. The reason that the impurities will float, even when they are heavier than water, is that microscopic air bubbles attach themselves to the suspended solids, or flocks, and make them buoyant. 6.2

OPERATIONAL DESCRIPTION:

The process for forming the air bubbles is as follows: 1. Water, pressurised to 5-6 Bar enters the Air Dissolving Tube (ADT) through the inlet. The water enters tangentially and spirals through the length of the tube. 2. Compressed air is injected through special air dispersion panels. 3. The water and air are mixed rapidly within the tube for 10 seconds before exiting the tube outlet. Any un-dissolved air accumulates in the centre and is separated out by the bleed-off line in the centre of the tube. 4. The pressure is released into the SEDICELL. When the pressure is released, the water can no longer hold the dissolved air in solution. This causes microscopic air bubbles to spontaneously form throughout the liquid. If clean water is used, it will take on a milky white appearance. This can be seen by taking a sample of the mixture in a clear container. The rise rate of the proper sized air bubbles should be no faster than approximately 8 - 12cm.per minute. (For proper operation, the bubbles formed should be smaller than the particles, or flocculated material they are removing).

O&M Manual for Krofta Sedicell (SDC-22)

Page | 15

Viva Boards Pvt. Ltd.

6.3

ADT COMPONENT DESCRIPTION:

6.31

AIR DISSOLVING TUBE: The tube is designed to retain water and air under pressure. The pressure and swirling in the tube causes the air to become dissolved in the water. The ADT requires a minimum flow (pressure drop) to work properly similar to operation of a centrifugal cleaner. Any undesirable, large undissolved air bubbles tend to collect along the central axis of the ADT. This air is continually removed to prevent the tank from filling with air.

6.3.2 AIR ROTAMETER: The amount of air needed by the ADT depends on the water flow through the unit and the amount required to properly float the solids. The amount is a small percentage of the amount of water required. The air quantity is precisely metered by an Air Rotameter. The compressed air supplied to the ADT must be pressure regulated and filtered of any oil or moisture. Minimum gauge pressure should be 6 Bar or at least 1.0 Bar higher than the internal ADT pressure. If more than 1 Bar is required to push air into the ADT, the dispersion panels have clogged from oil and other contaminants and must be replaced. Pressure drop on the panels should be checked monthly.

The air meter needle valve(s) require adjustment for the proper airflow reading, initially set at 30 l/min. The air enters the ADT through internal dispersion panels and is mixed and dissolved into the water. 6.3.3 A.D.T. PRESSURE RELEASE SYSTEM: The pressure built up in the ADT is released in a globe valve. This provides a high degree of shear to generate air bubbles of the optimum size.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 16

Viva Boards Pvt. Ltd.

Air Dissolving Tube Back Pressure Back pressure in the air dissolving tube is controlled by the globe valve (s) situated on the outlet side of the ADT just before the aerated water line joins the main feed line just before the SEDICELL. 6.3.4. PRESSURE GAUGES: A Pressure gauge is provided at the ADT with one connection to the inlet piping be fore the entrance into the ADT and another connection to the main body of the ADT. Isolation valves are used to allow pressure reading from one connection at a time. The ADT contains a nozzle in the inlet connection which directs the water flow into a spiraling motion and which also causes a pressure drop. By noting the pressure difference between the two pressures gauge connection points, the rate of flow through the tube can be determined. The pressure drop should be at least 0.3 Bar showing 70% of rated flow. A drop over 0.7 Bar would indicate a higher than rated flow which may in turn effect the efficiency of the ADT. A drop of 0.5 Bar is normal. 6.3.5 SAMPLE VALVE: The sampling valve is used to determine if the air dissolving system is operating properly. Samples are drawn off to observe the flotation characteristics before the air/water solution enters the clarifier.

This sample point is an important tool for monitoring the ADT

operation. 6.4

ADT ADJUSTMENTS: Under normal circumstances, no adjustment should be needed after the initial set-up. If a problem should occur, make the following checks: 1. Take a sample from the sampling point.

This is the best indication of the ADT

operation. The sample should be drawn off into a graduated cylinder or other glass container. By looking closely, the air can be observed in the water. The air bubbles should be very small, giving the water a ‘milky’ appearance. Larger bubbles should not be present. If enough air is present, the bubbles should rise to the surface at a rate of 30 O&M Manual for Krofta Sedicell (SDC-22)

Page | 17

Viva Boards Pvt. Ltd. cm per minute, leaving clear water underneath. The ADT is functioning properly and requires no adjustment if this is what is observed. If the sample shows large air bubbles and/or poor flotation then check items 6.3.3 and 6.3.4. 2. Chemical Addition: Check to be sure that the chemical pump is functioning properly. A clear piece of pipe in the chemical feed line is useful to allow a visual check of chemical addition into the feed line. Generally, if the solid loading is increased to the clarifier then the amount of chemicals needed should also be increased in proportion. Overdosing with chemicals can sometimes cause ‘slippery’ floccs, which do not stick to the air and thus sink. This also causes the sludge to appear wet and ‘greasy’ and it would be very slippery to touch. 3. The Bleed-off from ADT: The bleed-off valve is an integral component of the ADT. It controls the proper amount of bleed-off from the system and also provides a good indication of the air/water solution from the ADT. The bleed-off is a pipe from the end of the ADT via a valve to drain. This should be regulated to ensure that a mixture of air and water is discharged into the DAF tank at all times, this valve is normally half open. If the valve should block, open it fully and reset to half open. If there is not enough air being added to the system, only water will discharge from the tube. First check the system to make sure that it is operating at proper pressure and flow. Increase air into the system in small quantities until proper air/water solution is discharged, or until flotation improves in the clarifier. If only air is discharged from the bleed-off, reduce the air meter settings. Excess air may cause turbulence in the clarifier or excessive foaming.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 18

Viva Boards Pvt. Ltd. 4. Pressure and flow adjustments : The pressure can be checked at three points in the system. a. Air pressure should be regulated at 6 Bar using the pressure control valve on the filter regulator. b. The pressure gauge at the inlet connection is used for readings of water flow into the ADT and for pressure in the ADT. See section 6.3.4 on Pressure Gauges. c. Pressure gauge at the outlet monitors the system pressure when the pressure release valve is adjusted. Check the pressure gauges daily to be sure the pressures have not changed. If b & c increases, this usually means the pressure release valve is plugging, the valve should be cleaned and reset to the correct pressure. 5. Shut-down and Start-up Procedures: For short term shut-down, no more than several minutes, the DAF recycle pump can be turned off while compressed air is left on. For longer period shut-downs or for maintenance, the pump and compressed air should both be turned off. The water remaining in the ADT should be drained off. All connecting pipe lines should also be drained. At start-up, close all drain valves, turn on the air compressor and start the pump. The pressure gauges should be checked and a sample of the air/water solution should be taken after the system stabilises. NOTES: Operating the recycle pump with the air supply off, can cause the dispersion panels in the ADT to clog and back flow water into the air lines.

O&M Manual for Krofta Sedicell (SDC-22)

Page | 19

Viva Boards Pvt. Ltd.

Annexure-A SPARE PARTS LIST

RECOMMENDED SPARE PARTS: a. Vyon sheet b. Traction wheel c. Idler wheel d. Spiral scoop saddle

O&M Manual for Krofta Sedicell (SDC-22)

Page | 20