Met-L-Chek. Guide to Penetrant Waste Water Treatment

Transcription

1 1 1 of 11 During the penetrant inspection process water is employed to remove the surface penetrant with Methods A, B, and D. This results in a high volume of liquid with a small amount of penetrant in the case of Method A, or penetrant/ emulsifier in the case of Methods B & D. Typical penetrant process waste water contains ppm of penetrant inspection material as a contaminant. This is a small amount of material but since the materials are intensely colored, (yellow green in the case of Type 1 fluorescent and reddish pink for Type 2 visible) attention is drawn to the effluent stream. The discharge limits in different municipalities vary widely depending upon the treatment capabilities of the local POTW (public owned treatment works) sewage plant. Sampling is usually at the property line which means the penetrant waste stream has been diluted by other facility waste streams and contaminated with their particular waste. Discharge limits address such things as turbidity, total dissolved solids, BOD (biological oxygen demand), COD (chemical oxygen demand), FOG ( fats, oils and greases), heavy metals and a growing list of specific chemicals. The required analysis to detect some materials is quite sophisticated and many municipalities are not adequately equipped to differentiate between some acceptable and unacceptable chemicals. Met-L-Chek has developed a line of penetrant materials which will accommodate the requirements of most discharge regulations. It should be noted that even the most environmentally friendly products can not be put down the drain as concentrates but only in the as used condition of high dilution ratio. There is no single national POTW standard so the user must check the local discharge regulations to make sure of compliance with the local facilities capabilities. In view of the fact that regulations are dynamic, and analysis interpretations are not foolproof, there are situations where even the use of environmentally friendlier products will not pass the local requirements and the penetrant process effluent must be treated or hauled away for treatment. This is accomplished most easily at the source of waste generation rather than after several different waste streams have been combined. There are a number of methods available which can help in meeting the regulations. Bleach In many cases it is only the color of the discharge that is of concern to the POTW. Plain old bleach will quickly kill the color. This is usually done in batches where the waste water is collected and treated in a holding tank, then discharged. Check regulations for local acceptability. Carbon Filtration This is one of the oldest and most commonly used methods of reducing the content of penetrant materials in the effluent stream. It is effective in removing the color and hydrocarbon content in a continuous stream process. The emulsion associated with water washable penetrants often reduces the effective life of the carbon. When the reuse of water in the process is desired carbon filtration following one of the other methods is recommended to ensure removal of trace amounts of surfactants. Evaporation Special evaporation equipment is available which will boil off the water and allow the residue to be collected and disposed of by a waste hauler. This is a high energy consumption approach and flirts with air pollution regulations.

2 Absorbent Media Penetrant waste water is treated with electrolytes and then mixed with absorbent clays. The mix is filtered and the solids disposed of as solid waste. This proved to be a bit cumbersome. Newer absorbent media have been developed that are more selective and will take hydrocarbons from water more readily in stream processing. There are specialized systems available that automate much of this process. Coalescer The use of this method relies heavily on the incompatibility of the penetrant and water. It is very effective with post emulsifiable penetrants especially in the pre rinse water. It becomes less effective with emulsions associated with water washable penetrants. Newer types of coalescer media and processing techniques have improved this methods effectiveness with some emulsions but it is still viewed as a PE penetrant process treatment method. Ozone This method has been demonstrated to quickly remove color but may not be as rapid in a stream process at reducing the total organics as desired. Batch processing may be needed to reduce the BOD and COD levels to meet some regulations. This is an approach that is more effective on solvent based penetrants than the surfactant based biodegradable penetrants. It is useful as an add on method to sanitize water when water is recycled. Membrane Filtration There are several types of filtration covered by this general heading. In a nut shell it is a filter method that uses a media with molecule selectivity to allow water to pass through it but not larger hydrocarbon molecules. The membranes may be hollow tubes and fibers or spiral wound sheets. Ultra filtration and nano filtration have been used with varying success on penetrant effluents. The methods are expensive initially and require considerable membrane maintenance. The membranes must be protected from particulate matter in the waste stream so prefiltration is often required. The selection of the right molecular weight membrane and membrane material are keys to success. The method works by concentrating the penetrant waste by de-watering the waste stream during a series of passes through the membrane. The concentrated penetrant waste is then collected and disposed of as a liquid waste through a waste disposal handler. The discharge water from this process can generally go down the drain. Following membrane filtration with carbon filtration will yield very clean water, which can be reused in the penetrant process. Nano filtration is more effective with surfactant based penetrants than ultra filtration. Both methods work well with oil based penetrants. Large facilities with multiple operations often have complex waste water treatment systems utilizing some aspects of several approaches. The growing need is for the small operation, which has a very limited amount of penetrant process water to deal with. A complex waste treatment plant is not the answer. Treating the penetrant waste stream by itself near the source of waste generation is the practical approach. This simplifies the waste stream and facilitates the reuse of some of the waste water. Systems are available to treat as little as 50 gallons(189l)/ day of penetrant process waste water. The membrane processing unit is the size of a suitcase. A holding or processing tank is needed to hold the penetrant process wash water, which is recycled through the membrane unit. The unit extracts water, which can go down the drain, and slowly concentrates the contaminating penetrant, which is then collected and disposed of by a waste hauler. 2 2 of 11

3 3 3 of 11 Met-L-Chek has teamed up with Infinitex to offer a series of membrane treatment systems for small volume penetrant users. General layout for waste water treatment below. Pre-filter < 5µ Option or user supplied. Waste water from Splitter Line from pump from penetrant wash station or storage tank. User supplied. Waste water processing tank. Option or user supplied. Waste water to Splitter Cup strainer 80 mesh Pump Nano membrane Permeate water to drain. Concentrate drain Splitter Unit SPLITTER JR. base unit Capacity: 50 gallons/day (189 Liters/day) 24 hours Length: 17 (43.18cm); Width: 22 (55.88cm); Height:28 (71.12cm) Weight: 135 pounds (61.3 Kg), portable with rubber wheels Pump/Motor:1 hp, close coupled straight, stainless steel, centrifugal 115VAC,60Hz, 1PH (for 50 cycle electrics an inverter is required). Controls: Microprocessor with 3-position timer, PSI gauge, high temperature warning light, low pressure cutout, thermal motor overload protection. High temperature limit: 145 F ( 62.7 C) ph:2-11 Pre-filter:80 mesh suction strainer type. Membrane:1 spiral wound 3.5 x 9 nano

4 Penetrant Inspection Materials 4 4 0f 11 SPLITTER Capacity: 125 gallons/day (473 Liters/day) 24 hours Length: 17 (43.18cm); Width: 22 (55.88cm); Height:28 (71.12cm) Weight: 140 pounds (63.5Kg), portable with rubber wheels Pump/Motor:1 hp, close coupled straight, stainless steel, centrifugal 120VAC,60Hz, 1PH. (for 50 cycle electrics an inverter is required). Controls: Microprocessor with 3-position timer, PSI gauge, high temperature warning light, low pressure cutout, thermal motor overload protection. High temperature limit: 145 F ( 62.7 C) ph:2-11 Pre-filter:80 mesh suction strainer type. Membrane:2 spiral wound 3.5 x 9 nano SPLITTER XD Capacity: 250 gallons/day (945 Liters/day) 24 hours Length: 17 (43.18cm); Width: 22 (55.88cm); Height:36 (91.44cm) Weight: 155 pounds (70.3 Kg), portable with rubber wheels Pump/Motor:1 hp, close coupled straight, stainless steel, centrifugal 120VAC,60Hz, 1PH (for 50 cycle electrics an inverter is required). Controls: Microprocessor with 3-position timer, PSI gauge, high temperature warning light, low pressure cutout, thermal motor overload protection. High temperature limit: 145 F ( 62.7 C) ph:2-11 Pre-filter:80 mesh suction strainer type. Membrane:2 spiral wound 3.5 x 19 nano

5 Commonly asked Questions What size do I need? How much waste water is being generated in 24 hours is a key factor in sizing the unit needed. It is surprising how many penetrant line operators have no idea how much water is being consumed in 24 hours. If the process line is a very low volume penetrant line used only occasionally then a 50 gallon Splitter Jr. unit might be the right choice, but if the use is sporadic with high volume use and then low volume use a larger unit is advisable to accommodate the high volume periods. Also as the membranes age they do tend to slow down permeate passage so sizing up will maintain better processing over time. It is wise to have more processing capability than to save a little up front cost and be under sized in the long run. The focus here is on the small units ideal for the very small penetrant processors. Larger units which are skid mounted are available for 500 gal, 1000, gal and 3000 gal waste generators. 5 5 of 11 Why is there a prefilter? Penetrant wash tank water is pumped to a processing tank through a prefilter. The prefilter will eliminate particulates from the penetrant process, such as developer, shot blast residues, or other materials that may have made it through the penetrant process to the wash tank and are smaller than the units 80 mesh cup strainer. This is recommended as insurance to protect the nano membrane. What is the process tank for? Membrane filtration is not used as a through stream process but rather as a batch process treatment. The waste water in the process tank is pumped, by the Splitter unit, through the cup strainer passing through the membrane and then back to the waste water processing tank. As the waste water passes through the membrane a small amount of permeate (clean water) passes through the membrane and out of the Splitter unit as disposable water. This continues and the volume of waste water in the process tank drops and what remains increases in contamination. This continues until no more water can be extracted, at which point the batch is done. The concentrated contaminates are then emptied into a waste drum for eventual disposal by a waste hauler as an oily waste which is often incinerated. Does this mean I can only process for one day? It is most common to process for a week but every situation is slightly different. As the waste water is recycled through the Splitter unit and the volume in the process tank drops, more waste water can go into the process tank, until the contamination level is too high to permit further concentration. It is important to size the process tank to

6 6 6 of 11 allow for this or to have a larger primary holding tank to feed the process tank and then empty the processing tank once it is concentrated. By ordering the Auto Start feature the Splitter unit will turn on and off automatically with the volume in the process tank. The float switch feature can be added to users own tank with supplied instructions but the Auto Start feature must be ordered with the initial unit order. How often do I need to change the membranes? Membranes will last for about a year depending on processing volume, proper system maintenance, type of penetrant material in the waste water, and the introduction of unacceptable materials into the waste stream. As membranes age the permeate rate will slow, but the quality of the permeate will remain high. As long as the flow rate is acceptable for the waste process volume the membrane can continue to be used. What system maintenance is required? The first thing is to not push the over concentrating of the waste stream, when the permeate (clean water) out put drops, it is time to flush the system. The processing is stopped and cleaner is flushed through the membrane system. This done the processing is restarted. Some penetrant materials are especially prone to fouling the membranes and to prevent this a special additive is introduced into the processing tank that prolongs the processing efficiency. Depending on volume of processing and penetrant materials used, flushing and system cleaning should only be required once a week under typical conditions. What can go through the system? Particulates have been addressed above, if not they will plug the membrane. Free oil should be skimmed from the waste stream and can shorten membrane life. The system was purchased to process penetrant waste water washings, keep solvents, acid and caustic solutions out of the process tank. Janitorial waste water should also be kept out of the processing tank. What cleaning materials are needed? Generally the only cleaning agent required is Detex-NS TM which is a liquid material. The cleaner is diluted for membrane cleaning at 2 ounces per 5 gallons of water. This is flushed through the membrane. This same material may be added to the waste water process tank when difficult to handle penetrant materials are present. As an antifouling agent it is diluted at 4 ounces for 50 gallons of waste water. Can the clean water be re-used for the penetrant process? The water that comes from the Splitter unit is clean enough to generally go to the discharge sewer, and can be reused for the penetrant process but there are some guide lines that need to be followed. For reuse it is suggested that the water pass through a carbon filter to remove any traces of water soluble fluorescent brightener or surfactant, that may make it through the membrane system. These are in such small amounts they generally pose no discharge restrictions. The water has to be stored in a tank until it is needed for the wash station. Water sitting around grows bugs, so some form of sanitizing of the water is needed. Ozone generation will sanitize the water and also oxidize any remaining water soluble penetrant constituents. Using ozone for the re-used water would eliminate the need for the carbon filtration of the permeate. The cleaned water needs to be returned to the penetrant wash station by

7 pumping to the wash gun or nozzles. There will need to be fresh water added to the system to make up for the water discharged in the waste concentrate and through evaporation. Pre-filter < 5µ Option or user supplied. 7 7 of 11 Line from pump from penetrant wash station or storage tank. User supplied. Waste water processing tank. Option or user supplied. Waste water from Splitter Waste water to Splitter Cup strainer 80 mesh Pump Nano membrane Permeate water holding tank. Option or user supplied. Ozone generator supplied with tank option Concentrate drain Splitter Unit Permeate water to tank. To wash station Option or user supplied. Pump What comes with the basic unit? The base Splitter system is as described on pages 3 and 4. The suitcase sized membrane unit comes with a reusable cup strainer(80 mesh), high pressure pump(115v/60hz/1ph), nano membrane, and microprocessor controls. The Controls include : automatic PulseKleen, 3-position timer, high temperature warning light, high temperature limit, low pressure cutout, and pressure gauge. The system includes two 8 liquid hoses with quick connects and ball valves for intake into the unit and return to the process tank. A pick up tube is included which is used if a 55 gal drum, tote or similar container is used for the processing tank. Will the unit work on 50 cycle electric current? The unit is designed to run on 115V/60Hz/1ph electric, but can be ordered with an inverter to allow use with 220/50Hz electric. The small footprint of the unit restricts the high pressure pump size required for 50Hz operation. The inverter takes up very little space in the unit cabinet. Can I supply my own tanks, prefilter, and pumps? The packages offered cover the commonly needed extras and intallation of fittings in the tanks. Users can supply their own add on components if they choose. Tanks: It is recommended that the tanks be fiberglass or stainless steel, as some penetrant materials will shorten the life of poly tanks. The tank should be cone bottomed with a bottom drain.

8 8 8 of 11 Prefilter: User can supply their own, but should be aware that some filter cartridges use plastics that are attacked by penetrants. The unit must be able to reduce particulates to at least 5µ. Unit supplied as option contains two graduated filters in series, first one is 75µ to 25µ and the second one is 25µ to 1µ. Auto Start: This option will turn Splitter unit on when the process tank is full and off when process tank volume is low. This feature must be ordered with initial unit order even if user is supplying their own tank and wishes to install the float devices later. Instructions for float tank installation can be provided. Pumps: Option return pump for recycled waste water to penetrant wash station is an air diaphragm pump. The Splitter Unit pump handles drawing the waste stream from the process tank to the unit and back to the process tank. User can provide their own pumps were desired. Plumbing: Do not use PVC or CPVC pipe, valves or other couplings for any of the penetrant waste water connections. Penetrants make these brittle causing failure. Automatic (float switch) Operation The process tank, supplied in the packages, is equipped with an adjustable float switch that can be used to turn the system on and off, based on the waste level in the tank. The Auto Start feature comes with the package. Manual Mode After the power switch is turned on, if the start switch is used to start the system in the first 10 seconds, the system will run for the amount of time selected with the timer switch. Auto Mode If the start switch is not used in the first 10 seconds after power-up, the system will look to the float switch for control. When the level in the tank rises to the HIGH float switch position, the system will begin processing. When the level in the tank drops to the LOW float switch position, the system will stop processing. This mode of operation will continue as the level rises and falls. During the pause when the float switch is in the LOW position, the READY LED will flash green to indicate that the system is waiting for the tank level to rise. Note: The system will NOT time out when in Auto mode. Float Switch Adjustment The distance between the ON and OFF levels of the float switch can be easily adjusted by loosening the black gland nut and pulling the cord out (to decrease the distance between the ON and OFF levels), or by feeding cord into the tank (to increase the distance between the ON and OFF levels). The point at which the float switch closes (HIGH level) or opens (LOW level) can be heard as a clunk when the float is manually raised or lowered. Float Switch Connection Connect the plug on the end of the float switch cord to the receptacle on the side of the Splitter.

9 Budgetary 9 9 of 11 Users can purchase the basic unit and supply their own options. For those wanting to do far less sourcing we offer the following packages. Pricing shown is budgetary only till 12/14 actual pricing will be provided at time of inquiry. It is recommended that extra Pre-filter cartridges (4/case) and 5 gallons of Detex-NS be ordered with the unit to avoid system maintenance issues. Splitter JR: $ Splitter JR-RTU: $ Splitter JR (50 gallons/24 hr) 1-50 gallon round dished bottom open top fiberglass process tank( 24 D x 35 H; 40 lbs.) plumbed with valve 1-1- Pre-filter assembly with 2 filter housings, 2 filters (75µ and 25µ), pressure gauge and mounting bracket, 9 D x 15 W x26 H, wt 25 lbs. Splitter JR-RE: $ Splitter JR (50 gallons/24 hr) 1-50 gallon round dished bottom open top fiberglass process tank( 24 D x 35 H: 40 lbs.) plumbed with valve 1- Pre-filter assembly with 2 filter housings, 2 filters (75µ and 25µ), pressure gauge and mounting bracket, 9 D x 15 W x 26 H, wt 25 lbs gallon round dished bottom open top fiberglass process tank( 24 D x 35 H: 40 lbs) equipped with Ozone Sanitizer 115V/60Hz; 0.1 amp (4 lbs), (220VAC,50/60Hz 1 amp available with up charge). 1- Air Diaphragm pump with regulator and valve for pumping clean water to inspection wash station; Air pressure psi, Max. air consumption 28 scfm, liquid inlet and out let 3/4 NPT, 11 H x 9 W x 7 D, weight 12 lbs.

10 Budgetary of 11 Splitter: $ Splitter-RTU: $ Splitter JR (125 gallons/24 hr) gallon round dished bottom open top fiberglass process tank( 24 D x 75 H: 75 lbs.) plumbed with valve 1- Pre-filter assembly with 2 filter housings, 2 filters (75µ and 25µ), pressure gauge and mounting bracket, 9 D x 15 W x26 H, wt 25 lbs. Splitter-RE: $ Splitter JR (125 gallons/24 hr) gallon round dished bottom open top fiberglass process tank( 32 D x 55 H; 80 lbs.) plumbed with valve 1- Pre-filter assembly with 2 filter housings, 2 filters (75µ and 25µ), pressure gauge and mounting bracket, 9 D x 15 W x 26 H, wt 25 lbs gallon round dished bottom open top fiberglass process tank( 32 D x 55 H; 80 lbs) equipped with Ozone Sanitizer 115V/60Hz; 0.1 amp (4 lbs), (220VAC,50/60Hz 1 amp available with up charge). 1- Air Diaphragm pump with regulator and valve for pumping clean water to inspection wash station; Air pressure psi, Max. air consumption 28 scfm, liquid inlet and out let 3/4 NPT, 11 H x 9 W x 7 D, weight 12 lbs.

11 Splitter XD: $ Budgetary of 11 Splitter-XD-RTU: $ Splitter JR (250 gallons/24 hr) gallon round dished bottom open top fiberglass process tank( 38 D x 63 H; 105 lbs.) plumbed with valve 11- Pre-filter assembly with 2 filter housings, 2 filters (75µ and 25µ), pressure gauge and mounting bracket, 9 D x 15 W x 26 H, wt 25 lbs. Splitter-XD-RE: $ Splitter JR (250 gallons/24 hr) gallon round dished bottom open top fiberglass process tank( 38 D x 63 H; 105 lbs.) plumbed with valve 1- Pre-filter assembly with 2 filter housings, 2 filters (75µ and 25µ), pressure gauge and mounting bracket gallon round dished bottom open top fiberglass process tank( 38 D x 63 H; 105 lbs.) equipped with Ozone Sanitizer 115V/60Hz; 0.1 amp (4 lbs), (220VAC,50/60Hz 1 amp available with up charge). 1- Air Diaphragm pump with regulator and valve for pumping clean water to inspection wash station; Air pressure psi, Max. air consumption 28 scfm, liquid inlet and out let 3/4 NPT, 11 H x 9 W x 7 D, weight 12 lbs.