Sewage aeration systems

Transcription

1 GRUNDFOS DATA BOOKLET Sewage aeration systems Disc and tube diffusers

2 Sewage aeration systems Table of contents 1. Product introduction 3 Applications 3 Features and benefits 3 2. Identification 5 Type key 5 3. Product selection 6 Selection and sizing 6 How to order 6 4. Performance range 9 Performance overview 9 5. Product range Installation 12 Assembly drawings 12 Component and pipe list Product description 13 Process description 13 Product description 14 System description Performance curves and technical data 21 Curve conditions 21 How to read the performance curves 21 Disc diffuser 9", fine bubble diffuser (1-1) 22 Disc diffuser 9", fine bubble diffuser ( ) 23 Disc diffuser 12", fine bubble diffuser ( ) 24 Disc diffuser 5", coarse bubble diffuser 25 Tube diffuser 2", fine bubble diffuser (1-1.5) 26 Tube diffuser 2", fine bubble diffuser (2-2) 27 Tube diffuser 3", fine bubble diffuser (1-1) 28 Tube diffuser 3", fine bubble diffuser (2-2) 29 Tube diffuser, coarse bubble diffuser Accessories 31 s 31 Diffusors 31 Supports 31 Purge 31 Connections 32 Other accessories Further product documentation 33 WebCAPS 33 WinCAPS 34 2

3 Sewage aeration systems 1 1. Product introduction This data booklet describes Grundfos sewage aeration systems. These types of diffuser are available: Grundfos fine bubble tube diffusers Grundfos coarse bubble tube diffusers Grundfos fine bubble disc diffusers Grundfos coarse bubble disc diffusers Fig. 1 Diffusers family Applications Sewage aeration systems can be used for two main applications: Providing oxygen transfer Mixing where oxygen transfer is not a priority. Disc and tube diffusers for bottom-diffused aeration in wastewater treatment plants provide oxygen and mixing for: biological process tanks sludge aeration equalisation tanks grit traps other processes where air supply is needed. Grundfos offers complete aeration systems with disc or tube diffusers fitted. The systems can be designed as fixed or retractable systems. Furthermore, Grundfos provides air compressors to deliver air to the sewage aerations systems. The Sewage Aeration Compressor (SAC) range consists of highly efficient direct-driven compressors. For more information, go to webcaps to see SAC data booklet or contact Grundfos. TM Features and benefits Product features Fixed and retractable aeration systems to suite versatile applications. Different materials for air distribution piping to suit fixed and retractable systems as well as different submergence levels in a cost efficient way. System components in a range of materials suitable for different wastewater characteristics. Condensation purge systems to remove collected moisture in the pipes and to keep moisture level under control. A large range of disc and tube diffusers to suite all needs. Diffusers are fitted with a standard durable EPDM membrane. For special wastewater applications, other membrane materials are available. Flexibility of the elastomeric membrane ensures fully closed diffusers when air supply is off. This allows for on/off operation of the aeration system without the risk of the membranes clogging in SBR (Sequence Biological Reactor) systems or in zones of simultaneous nitrification/denitrification. The non return valve "built in" the membrane will also prevent sludge to enter the system via the membrane. A non-return valve is integrated in the membrane to prevent sludge ingress into the air distribution pipes. (Furthermore available as an additional internal separate valve.) Non-opening knobs on the reinforced diffuser back plate and the threefold threaded retainer ring ensures that the membrane will not accidentally slip off the disc diffuser. Customised solution When designing aeration systems, Grundfos takes into account the complex interplay of sewage type, based on AOR SOR [kg O 2 /h] (Actual Oxygen Requirement Standard Oxygen Requirement, respectively. The design of the grid layout is based on the active surface of diffusers in the basin and airflow per diffuser to obtain an efficient system. The customising process is based on the criteria set out by the customer with respect to initial investment levels and long-term standard aeration efficiency (SAE) [kg O 2 /kwh]. To meet customer requirements and to provide the required oxygen transfer rate, we design the optimum system based on components, materials and solutions in our range. Product introduction 3

4 1 Sewage aeration systems Product introduction Uniform aeration The diffuser design ensures a uniform air distribution and bubble release across the membrane surface. With our large range of sturdy and flexible disc and tube diffusers, our systems can be designed to deliver fine bubbles at a wide range of air rates. Fast installation Fast on-site installation. To minimise construction time, Grundfos aeration systems are delivered partially assembled on-site, in carefully numbered crates and boxes, itemised in detail. All gluing, solvent welding and cutting for plastic piping is done in the workshop before shipment. With one-bolt connections, on-site installation of the air distribution pipes is fast and easy. Fully adjustable piping supports in stainless steel for installation flexibility and easy levelling. Expansion/contraction is controlled through mechanically fixed flanges in sliding supports. Working layout drawings included to ensure fast and installation. 4

5 Sewage aeration systems 2 2. Identification Type key The Grundfos sewage aerations can be identified by means of the type designation. See example of type designation below. Identification Code Example SAD. F. 9. D. A. EP SAD F 9 D A EP Sewage Aeration Diffusers Bubble type C Coarse bubbles F Fine bubbles Diffuser size 5 (5" diameter) 9 (9" diameter) 12 (12" diameter) 2500 (2" width / 500 mm length) 2606 (2" width / 606 mm length) 2750 (2" width / 750 mm length) (2" width / 1000 mm length) 3500 (3" width / 500 mm length) 3750 (3" width / 750 mm length) Diffuser type D Disc T Tube Thread size A 3/4" NPT B ISO G 3/4" material EP EPDM rubber SE Silicone/EPDM rubber SI Silicone PU Polyurethane SS Stainless steel (304) Perforation (size of hole (x10)) mm mm mm Perforation (distance to next hole (x10)) mm mm mm mm mm 5

6 3 Sewage aeration systems Product selection 3. Product selection Grundfos sells diffusers as part of complete bottom-aeration systems, or as single diffusers for maintenance and replacement in existing systems. Selection and sizing Selection and sizing of an aeration system is a task that requires insight into the application and aeration equipment as well as a thorough knowledge of how the interplay between the different components will provide maximum oxygen transfer efficiency. The aeration system is sized based on the oxygen requirement of the process. The process oxygen requirement is calculated from the load of organic matter, endogenic respiration of the activated sludge and nitrification rates of the process. This oxygen requirement is converted to a Standard Oxygen Requirement (SOR) which can be used to calculate the required airflow and number of diffusers for the aeration system. Product selection tool When sizing the installation, a number of factors must be taken into account. Grundfos uses an in-house selection tool, which ensures that all factors are taken into consideration. For more information, please contact Grundfos. How to order For final sizing, selection and placement of equipment or adjustment of selected equipment, support can be obtained from Grundfos. Certain information must be available in the enquiry to support and select the most appropriate solution for the application. The process of making an enquiry and obtaining an offer for a sewage aeration systems is the following: 1. Inquiry for a bottom aeration system (fill out an inquiry form). 2. Based on the inquiry form, calculation by Grundfos selection tool will be performed. 3. Grundfos will make an pre-offer. 4. Adjustments/customising aeration system. 5. Confirmation and agreement. 6. Order in action. 7. Delivery/commissioning. Enquiry form The enquiry form will serve as a check list and provide sufficient information to the engineering department about the specific application of the sewage aeration system. This information must be filled out in the enquiry form: Oxygen demand as either SOR (Standard Oxygen Rate) or AOR (Actual Oxygen Requirement) If AOR; water temperature, site altitude, Alpha factor, Beta factor and DO must be included. Type of wastewater Tank geometry Preferred type of diffuser (disc or tube diffuser). If no preference is selected, standard components applicable for the conditions will be used. Preferred type of installation (fixed or retractable) If no preference is selected, standard components applicable for the conditions will be used. Preferred type of pipe material If no preference is selected, standard components applicable for the conditions will be used. Preferred type of pipe support If no preference is selected, standard components applicable for the conditions will be used. Airflow, if information on existing compressors is available Special requirements / Additional information Optional equipment / Accessories Evaluation criteria used for contract award. In addition, a dimensional drawing of the tank must be provided. All data requested must be in place, as it is not possible to make an offer before such time. To receive an enquiry form, contact Grundfos. Based on the information above, Grundfos will prepare an offer. The offer will include a calculation of system performance and suggestions for layout of aeration system. 6

7 Sewage aeration systems 3 Background information for sizing A central parameter for comparing aeration systems is Standard Aeration Efficiency (SAE), defined as the rate of oxygen transferred to the liquid per unit of power input (kg O 2 /kwh). SAE is dependent on a complex interplay between the system itself and conditions in and around the basin. For the designer, there are a number of parameters that can be adjusted to ensure optimal aeration. This example shows a refurbishment of existing basins; diffuser submergence and basin type are therefore given from the outset. The main variables that could be adjusted to ensure high oxygen transfer efficiency are: Bubble size - the size of the holes in the membrane Unit airflow - the flow through each diffuser Diffuser active surface - the number of diffusers. Bubble size The key to efficient oxygen transfer is the ascent velocity of the air bubbles and the air/liquid interface. This dictates the time and area available for oxygen to be transferred from the bubble to the surrounding liquid. Bubble size has a significant effect on oxygen transfer whereas the air/liquid interface of the air bubble directly influences the oxygen transfer rate. The air/liquid interface ratio and thus the oxygen transfer rate can be increased effectively by decreasing bubble size. Furthermore, fine bubbles have a lower terminal rise velocity, extending the time available for oxygen transfer. Airflow and active surface of diffusers Standard Oxygen Transfer Efficiency (SOTE) decreases as the airflow per diffuser increases (fig. 3), and a high airflow rate per diffuser will thereby increase operating costs directly. Ensuring sufficient airflow is fundamental to the oxygenation process. However, simply increasing the airflow to add more oxygen will have a negative impact on efficiency. The lower the airflow, the lower the energy consumption (kwh). In addition, the total head loss is increased because the counter-pressure from the membrane increases with higher airflow, further increasing the compressor power consumption. SOTE Fig. 2 Break even point Headloss Headloss SOTE SOTE and headloss as a function of airflow per diffuser TM The decrease in SOTE is due to the fact that air bubbles will increase in diameter and a coalescence effect takes place, all resulting in oxygen transfer reduction. SOTE Fig. 3 SOTE Fig. 4 SOTE as a function of airflow rate per diffuser 5 % 20 % [ surface/tank surface] SOTE as a function of diffuser active surface To achieve high aeration efficiency, Grundfos aims for a high diffuser active surface, which gives a lower airflow per diffuser. The greater number of diffusers gives a higher initial cost, but this is quickly offset by lower operating costs. Increasing diffuser active surface beyond 20 % will have the opposite effect on efficiency because the bubbles begin to coalesce, creating larger bubbles and reducing the air/liquid interface, see fig. 4. Higher density will also affect the possibility to work at the tank floor as there will be limited space for maintenance people to operate. Getting the materials right Generally speaking, the temperature of compressed air in such a system will increase by about 10 C/mWC. This factor results from elements such as submergence depth, pipework/fittings and counter-pressure at the diffuser membrane. In an installation with deep submergence and a high ambient temperature, the pressure to overcome head loss in the aeration system could push the air temperature (at the compressor) up to very high temperatures. The comparatively high temperatures mean that the piping in the basin needs to be in more heat-resistant PP or SS instead of the more commonly used upvc. PP increases the cost of the pipe work compared with upvc, but is equally durable and considerably more economical than stainless steel. upvc max. 70 C PP max. 100 C Stainless steel if t > 100 C TM TM Product selection 7

8 3 Sewage aeration systems Product selection Dealing with condensation The hot air in the system condenses readily in the submerged aeration grid, with water collecting at the lowest points. Such a build-up of water in the system reduces pipe diameter, increasing head loss and thereby operating costs. To relieve the aeration system of condensate build-up, a purge system is incorporated at the lowest points in the aeration grid. By ensuring a lower head loss through the purge system compared with the diffusers, an airlift function is created, forcing the condensed water from the grid. The discharge points of the purge system can either be above water in a manual system (tap) or at the bottom of the basin in a continuous, automatic purge system. While the manual system is quite time-consuming, a combination of both types of purge system can be made for extra assurance that the condensed water is being removed at all times and running cost kept to a minimum. The manual system gives the opportunity to se the drainage water from the airpipe system. Grey water means that the diffusor system is damaged as the sewage has entered the system, whereas clean water is only condensed water showing a system in a good condition. 8

9 Sewage aeration systems 4 4. Performance range Performance overview Figures 5 and 6 show the performance range of disc and tube diffusers. They give an overview of fine and coarse bubbles and various sizes. For performance of each individual diffuser, see pages 21 to 30. Note: Curves are shown at nominal design flow and a diffuser active surface of 5 %. Performance range SOTE Fig Nm³/h Performance range, disc diffusers TM Disc diffusers Bubble type Curve number Page SAD.F.9.D.A.EP SAD.F.9.D.A.EP Fine 2 23 SAD.F.12.D.B.EP SAD.C.5.D.A.EP. Coarse On request, please contact Grundfos 9

10 4 Sewage aeration systems Performance range SOTE Fig Nm³/h Performance range, tube diffusers TM Tube diffusers Bubble type Curve number Page SAD.F.2500.T.B.EP SAD.F.2500.T.B.EP Fine SAD.F.3500.T.A.EP SAD.F.3500.T.A.EP SAD.C.2606.W.A.SS Coarse

11 Sewage aeration systems 5 5. Product range The product range below shows single products. Aeration systems will differ from installation to installation. Below product range will be used multiple times in a system. For orders more than one unit, contact Grundfos for complete packages and system design layouts. Product range Material Disc diffuser Tube diffuser Diffuser type Diameter Diffuser length Selection of material variants The membrane for the diffuser is available in different materials. In most cases, EPDM will be the suitable choice of material for municipal wastewater treatment, whereas other membrane materials might be considered when treating industrial wastewater. However, for aeration systems, the membrane suiting the application will be evaluated based on the information given of the quality of wastewater. Guidelines for the overall restrictions of the different membrane materials are given below. For requests concerning working conditions in specific chemical compounds/liquids, please contact Grundfos. Product number Technical data SAD.F.9.D.A.EP Page 22 9" SAD.F.9.D.A.EP Page 23 SAD.F.12.D.B.EP " Page 24 SAD.C.5.D.A.EP. 5" Page 25 SAD.F.2500.T.B.EP Page 26 SAD.F.2750.T.B.EP Page 26 SAD.F T.B.EP Page 26 2" SAD.F.2500.T.B.EP On request Page 27 SAD.F.2750.T.B.EP On request Page 27 SAD.F T.B.EP On request Page 27 SAD.F.3500.T.A.EP On request Page 28 SAD.F.3750.T.A.EP On request Page 28 SAD.F T.A.EP On request Page 28 3" SAD.F.3500.T.A.EP Page 29 SAD.F.3750.T.A.EP Page 29 SAD.F T.A.EP On request Page 29 SAD.C.2606.W.A.SS Page 30 Standard membrane material Optional membrane material. For more information on membranes with these materials, see Selection of material variants, page 11. For on-request diffuser types, please contact Grundfos. For spare parts, pipe connections and other accessories, see page 31. EPDM EPDM/silicone Silicone Polyurethane Stainless steel ALSI 304 or 316L 11

12 6 Sewage aeration systems Installation 6. Installation At delivery of a sewage aeration system, Grundfos includes a working layout of the entire system. The working layout consists of a complete drawing of the sewage aeration system, assembly requirements and a component and pipe list. The sewage aeration system is delivered in sections with each item packed and numbered according to the component and pipe list. A package number refers to the shipment, and a code number refers to the assembly drawings. An example of how the system could be sorted in packages is shown below. Each package can consist of several boxes: Package 1 contains sections, such as drop leg, manifold and lateral piping. Package 2 contains diffusers. Package 3 contains brackets, purge system and accessories. Assembly drawings The assembly drawings show where the sections must be placed, as well as the assembly requirements. The assembly drawings provide the following assembly instructions and overview: Where to drill holes for anchor bolts Support assembly instructions Pipe assembly instructions Purge kit assembly instructions Connection of diffuser Numbering of components, such as screws and bolts, so that the components can be identified on the component and pipe list Torques for tightening of screw-in components. Component and pipe list The component and pipe list is a check list for all components of the sewage aeration system. The list provides the following information: Code number - unique code number which refers to the assembly instructions Description of components Quantity of each component Package - which box the components are packed in. 12

13 Sewage aeration systems 7 7. Product description Process description Aeration is a crucial process in the operations of a wastewater treatment plant. Aeration is used in the process of transforming wastewater to treated water and sludge. Grundfos aeration equipment for coarse and fine bubble aeration provides a highly efficient solution. Furthermore, a broad range of equipment designed specifically for wastewater handling and treatment is available, and Grundfos can supply a solution that is durable, cost effective, energy efficient and offers trouble-free operation. Application Wastewater enters the wastewater treatment plant at the inlet pumping station. For primary mechanical treatment, solids and sediments in the wastewater can be kept in suspension using mixers, from where solids can be filtered. Coarse bubble aeration allows grease to be skimmed from the surface, while sediments settle at the bottom and can then be removed. Secondary treatment removes suspended biological matter and to some extent dissolved matter. Biological treatment is the most commonly used method for treatment of wastewater to remove high amounts of organic matter and nutrients. The activated sludge process which is one of the most commonly used in biological treatment utilises the growth of specific floc-forming bacteria that live suspended in the wastewater. To create optimum conditions for the bacteria they are kept under specific process conditions and furthermore, a certain retention time for wastewater and sludge is necessary for the biological processes to take place. For aeration of wastewater during biological treatment, Grundfos offers fixed or retractable systems of fine bubble diffusers for efficient oxygen transfer. Fine bubble equipment consists of either disc diffusers or tube diffusers. Depending on preference or other issues, a thorough aeration can be obtained by using either one of these types. Non-pressurised systems made from stainless steel are also available for aeration of wastewater, and can be used for both mixing and aeration. For circulation of wastewater between different process zones, horizontal recirculation pumps, when applicable, keep vast flows at low head moving reliably. To avoid settling of the bacterial flocs in the process tank, mixers and flowmakers offer an optimum, energy-efficient solution. Sludge from the secondary clarifiers can be returned to the process tank using a pump from the range of SL, SE or S, pumps that handles total suspended solids up to 5 %. Grundfos can provide varoius dosing pumps and complete dosing systems. These can be used for applications of dosing coagulants, flocculants, substrate to enhance C/N or C/P ratios, and in tertiary treatment for disinfection. See the fig. 7 for an overview of the wastewater treatment process. Please contact Grundfos for further information. Product description Inlet pumping station 2 Screening Grit + grease removal 1 Neutralisation 2,3 Equalisation 1,2 Primary Clarification 3 Sludge Process tank 3 Anaerobic Sludge storage Process tank 3 Anoxic Process tank 3 Aerobic Settled sludge Sludge thickening 3 Sludge stabilisation Recirculation Secondary Clarification 3 Sludge dewatering 3 Final polishing 3 1.) Aeration. 2.) Mixing. 3.) Chemical dosing. Fig. 7 Overview over the wastewater treatment process 13

14 7 Sewage aeration systems Product description Product description The main components of an aeration system are shown in fig. 8. Fig. 8 Bubble size Main components of aeration system An important feature of the flexible membranes is the number of perforations, as well as their size and pattern. Perforations are produced by making small slits in the membrane without removing any rubber. Each hole acts as a variable aperture which opens at membrane inflation when air supply is turned on. Diffusers are normally characterised by the size of the slits, hence the size of bubbles the membrane delivers. Diffusers delivering bubbles of mm in diameter are termed fine bubble diffusers whereas diffusers delivering bubbles above this size are termed coarse bubble diffusers. Fig. 9 Fine and coarse bubbles Diffuser Lateral pipe Pipe support Connection to drop leg Manifold A membrane perforation of (1-1) means that each slit of the membrane is 1 mm with a 1 mm space to the next slit. This perforation gives an approximate bubble size of 1 mm in diameter and the diffuser is termed a fine bubble diffuser. The smaller the slits, thus the bubbles produced by the membrane, the better the oxygen transfer rate, but in contrary the higher the head loss across the membrane will be. For larger bubbles, the oxygen transfer will decrease, as will the head loss across the membrane. This implies that when air flow is important for the application, diffusers delivering coarse bubbles should be used. TM TM TM The ideal membrane perforation for oxygen transfer consists of small and separated slits. This kind of perforation gives an efficient oxygen transfer rate compared to the head losses. Furthermore, the separated slits reduce the risk of bubble coalescence, as bubble coalescence will generate larger bubbles, which will decrease oxygen transfer rates. Diffuser membrane perforations and size For the traditional applications in municipal or industrial wastewater treatment plants, a membrane opening of 1 mm - 1 mm (1-1) is typically employed. This perforation gives good oxygen transfer efficiencies with a modest pressure loss through the overall system. The (1-1) perforation has demonstrated long-term serviceability in performance by minimising the potential for fouling compared to smaller openings. However, with a specific tank design, the combination of available space for the sewage aeration system and requested SOR, thus the airflow through the diffusers, might require another perforation of the membrane. The membrane must be chosen to fulfil process requirements in order to operate at its nominal airflow. Operating diffusers at too high airflow can reduce lifetime or performance of the membrane as this will increase stress and induce a higher temperature on the membrane. Also, with a too low airflow through the membrane, performance can be reduced. This is mainly due to the fact that not all slits of the perforation will discharge air but also due to the fact that the membrane will foul more easily. See the characteristics of diffusers in the Grundfos range from pages 21 to 30. For each type of perforation, the principle relationship between airflow rate per diffuser, SOTE per metre and head loss over the membrane shows that increasing the airflow above the nominal value will increase the operating cost of the system as SOTE per metre decreases while the head loss increases. During operation the membranes will foul and over time, cleaning with acid will make it possible for the membranes to regain their flexibility. Special acid dosing system can be inserted to the dropleg and by means of that it will be possible to dose sufficient acid. When the membranes are not supplied with air the mid section of the disk diffuser membranes will act as a nonreturn valve as the mid section is not perforated as the rest of the membrane surface. The mid section will act as a lid against the hole supplying air to the membrane. An extra nonreturn valve can be added in the inlet to the disc diffusers, see accessories page

15 Sewage aeration systems 7 Tube vs. disc diffuser Grundfos offers two main types of diffuser designs, disc and tube. They are both designed with the objective to supply air and mixing to different processes at e.g. a wastewater treatment plant (WWTP). Both types of diffusers are available as both fine and coarse bubble diffuser. The most common is to use disc diffusers, as the disc diffuser is easy to install and is not as affected by the forces in the basin as a tube diffuser is. Tube diffusers are mostly used when a compact design of the aeration system is needed, e.g. when space is limited in the tank or in some cases when designing retractable systems. In a retractable sewage aeration system, the support frame (also used for air distribution) must be made of stainless steel. The diffusers which can handle the most air with the least stainless steel support are going to be an attractive choice. Typically, tube diffusers are seen on retractable systems for this reason. In bottom-mounted diffuser systems where the air distribution pipes are bolted to the floor, disc diffusers seem to be the preferred choice over tubes. Where system failure might be crucial for system performance, disc diffusers may be favoured over tubes. Tube diffusers typically have a large air orifice, hence in case of a membrane rupture or clamp failure, a large volume of air can escape from that orifice, possibly starving the rest of the system. However, fundamentally there is no difference between the two types of diffusers and one can easily be chosen over the other for either bottom-mounted or retractable systems without compromising aeration needs or system performance. System description Piping Pipe materials Pipeworks guiding the air from the compressor to the aeration tank often experience high temperatures. Due to this reason, the pipe material including the drop leg to the aeration grid is most often made of stainless steel to withstand the heat. Furthermore, metal is an excellent heat conductor, which helps to reduce the temperature of the air before it reaches the aeration system. Another reason is that it effectively resists corrosion at the point where the piping breaks the wastewater surface. At the aeration grid on the bottom of the process tank where the wastewater cools down the piping and thus the compressed air, upvc, PP or stainless steel can be used. For fixed aeration systems, the air temperature and price are the main factors that are considered, which results in the fact that upvc or PP is the choice of material. These two pipe materials are supplied in PN 10 (upvc) and PN 6 (PP) to make sure that the aeration system has a certain mechanical strength. Drop leg Stainless steel upvc, PP or stainless steel Aeration grid TM Product description Fig. 10 Piping material in system As a rule of thumb, PVC can be used if diffuser submergence is < 7 m, whereas PP should be used if the submergence is 7-10 m. However, the maximum attainable temperature should always be calculated for each specific project and materials chosen accordingly. (See Temperature increase of compressed air, page 18.) For retractable aeration systems, a certain mechanical strength of the grid is required in the construction, which results in the fact that stainless steel is the only durable option for these systems. 15

16 7 Sewage aeration systems Product description Pipe dimension When designing the pipeworks of an aeration system, it is important that the head losses within the manifolds and laterals are small compared to the resistance of the diffusers. This should be observed in order to obtain an even air distribution in the entire aeration grid. Typically, if head losses in the air piping between the last airflow split and the farthest diffuser are less than 10 % of the head loss across the diffusers, good air distribution through the aeration basin can be maintained, independent of pipe configuration. Fig. 11 Head loss across diffusers 1. Flow split 2. Last diffuser 3. Pipe head loss, must be < 10 % across diffusers. Grundfos offers a wide range of pipes in different materials and dimensions. Having different dimensions makes it possible to design the most economical solution with regards to head losses in the system, size of pipes, number of necessary drop legs and laterals. For instance, when a dimension of 110 for the lateral pipe is used, it is possible to use a pipe length of up to 45 metres with 70 diffusers per pipe, while still maintaining practically the same airflow capacity between the first and the last diffuser. When designing a sewage aeration system, the dimension of the manifold, thus the dimension of the drop leg, is chosen so that a minimum number of drop legs is needed compared to the required airflow. The system must be designed so that the air velocity in the air distribution pipes will not exceed m/s, as this will create an unacceptable increase in head losses and increase the noise level as well as create a risk of vibrations from the piping TM In some instances, the number of drop legs on the process tank is predefined (e.g. at refurbishments), and the aeration system should be designed accordingly. In these instances, it could be advisable to estimate the air velocity in the drop legs, as increased process loads etc. may have altered the required airflow compared to the previous system. If the air velocity has increased above the recommended velocity, we recommend making a detailed calculation and deciding if this is an acceptable solution. Coping with heat expansions Due to temperature variations of the system, expansions and contractions of the pipes must be expected. For stainless steel, the extent of expansions and contractions is small and no special precautions should be taken in aeration grid design. For upvc and PP, on the other hand, expansions and contractions must be taken into consideration when designing the aeration grid. This must be dealt with using flexible supports or sliding pipe connections. This type of support lets the pipe slide unhindered in the longitudinal direction and provides the aeration system with the flexibility that is needed to avoid pipe breaks. With a mechanical connection between the pipes, it is possible to keep an open pipe configuration in the system, which reduces pipe costs. Standards/procedures followed for joining pipe materials The grids for bottom-diffused aeration can, as described above, be made of stainless steel, upvc or PP. Joining of these materials is done according to the standards/procedures stated below: Stainless steel weldings: UNI EN ISO :2004 PP weldings: DVS Solvent welding and gluing of upvc: DVS

17 Sewage aeration systems 7 Purge system During operation, air is distributed in the sewage aeration system and released through the diffusers. This air is hot due to compression by the compressors (see Temperature increase of compressed air, page 18). The surrounding water is relatively cold compared to the air, which implies that humidity contained in the hot air will condensate on the inside of the aeration grid pipes and build up in the lowest point of the system. To relieve the aeration system of condensate build-up, a purge system is incorporated into the aeration grid. The purpose of the purge system is to remove the accumulated water from the pipes. If water is not removed, it will lower the air capacity of the system, increasing head losses. Furthermore, water might enhance corrosion and thereby lead to clogging of the membranes on the air side due to loosened corrosion products. The discharge of the purge system can either be placed above (manual purge system) or below water level (continuous purge system). It must, however, be ensured that the outlet of the purge system has a lower head loss than if air was to pass through the diffusers of the aeration grid. If this is ensured, the airlift function should be operational and condensed water be discharged from the grid. Fig. 13 Purge system suction 1. Purge system connection 2. Lowest point of an aeration system TM Product description TM TM Fig. 12 Manual and continuous purge system The continuous purge system should only be chosen if maintenance intervals of the system are infrequent as the continuous system will require that a slight amount of extra air is supplied to the system. As mentioned previously, the condensed water will accumulate at the bottom of the pipes at the lowest point of the aeration grid. As the click-on flanges for connection of the laterals are centred diametrically on the manifold, the manifold will normally be the lowest point of the aeration grid. The purge system should therefore be connected to the grid in a way so that it touches the lowest point of the system. When the purge system is open, it works as an airlift pump using the air supply from the compressor to force out the condensed water from the grid. 17

18 7 Sewage aeration systems Product description Head losses of the system To deliver air at the diffuser units of an aeration system, the compressor must provide air at a certain pressure at the drop leg to the aeration system. The pressure from the diffuser grid that must be overcome is made up of head losses from the following components: depth of diffuser submergence pipeworks and fittings diffusers. The head loss of the system due to contributions from the aeration grid is described by the equation below: H t = H s + H p + H d Unit Description H t mwc Total head loss (aeration grid) H s mwc Submergence depth H p mwc Head loss in piping H d mwc Head loss in diffuser and membrane Losses due to diffuser submergence are constant, whereas losses in the pipeworks and across the membranes are variable and depend on airflow rates. The head losses in the latter two contributors increase as a result of increased airflow rates. At constant airflow rates, losses in the pipe system will be more or less constant during the lifetime of the system. In contrast to this, the losses across the diffuser membrane will increase over time due to fouling effects and deterioration of the chemical structure of the membrane. The increase in membrane head losses will directly affect the total system losses. Because the losses in the pipes and losses due to submergence of the diffusers are constant over time, the increase in total losses can be used as a measure of when it is time to clean the diffuser membranes. To obtain an equal air distribution in the diffuser system, the diffusers must be exposed to equal head losses. This is due to the fact that air will leave the system at the point with lowest head losses. If the diffusers are not on level, air distribution in the system will be unequal and thus the application will not function optimally. When designing an aeration system, take into account that there is a head loss between the compressor installation and the diffuser system. Temperature increase of compressed air Generating the pressure to overcome the system head losses implies that heat will be generated as air is compressed. In general, the compressor air temperature increases 10 C per m of submergence, when air is rapidly compressed. To estimate the final outlet temperature of air from the compressor, the temperature of the inlet air must be added on top of the temperature rise due to head losses as described by the equation below: t t = t s + t o + t a Unit Description t t C Total temperature rise in system t s C Temperature rise due to submergence t o C Temperature rise due to other head t a C Ambient temperature The outlet air is supplied directly to the piping and membranes of the aeration system, which must be able to withstand the high temperatures. For a tank with a water depth of 8 metres, the increase in temperature due to diffuser submergence equals approximately 80 C, and with an ambient temperature of 20 C, the compressor outlet temperature will add up to approximately 100 C. The compressor is most often placed in a separate building some distance away from the sewage aeration system. Because of the temperature of the outlet air, it is conveyed to the sewage aeration system in stainless steel piping. During transport, the air temperature decreases slightly due to heat transfer to the air or ground where the pipes are placed. When the piping is submerged into the wastewater, the heat transfer from the distribution pipe increases, as water has a higher heat transfer coefficient than air. Due to the higher heat transfer and the decrease in air temperature during transport, plastic piping is in most instances used for floor distribution. However, the applicability of plastic piping due to heat should still be evaluated. The pipe temperature is the average between the air temperature and the water temperature. The average temperature of the pipe has to be below the limit temperature of the pipe material see Getting the materials right page 7. 18

19 Sewage aeration systems 7 Fixed system The fixed system is the standard solution, and in this case the sewage aeration system is mounted and bolted into the floor of the process tank. Depending on localisation of the dropleg the aeration grid can be made to suit tank floor and utilise the area at a maximum. Depending on the application the piping systems can be made of several pipe materials. Typically PVC, PP or Stainless steel pipes. PVC is primarily used when there is no special requirements because of the temperature due to deep tanks. Tanks deeper then 8 meters are typically not equipped with PVC. Using fixed installations requires that the tank needs to be emptied and cleaned before maintenance as the aeration grid has to be out of the water before any work can be done. Retractable system Some aeration systems for wastewater treatment will be installed at plants with a single process line or where process considerations prevent the tank from being dewatered for service and maintenance of the sewage aeration system. In these cases, a retractable sewage aeration system could be an alternative to a bottom-mounted system as the retractable system allows maintenance or service to be conducted without shutting down the process or dewatering the tank. This gives a more flexible operation of the aeration system with an easy procedure for maintenance. However, to have enough rigidity in the system when lifting it, stainless steel is the sole material that can be used for the frame. Using stainless steel for the piping increases system cost compared to using upvc or PP pipes. A retractable sewage aeration system is therefore mostly suited for plants with special needs as described above, for smaller plants with only few diffusers installed or where easy maintenance has high priority. Main components The main components of a standard retractable aeration system are shown in fig. 14. Support beam Wall guide Drop leg Manifold Bottom guide Counterweight Purge system Fig. 14 Retractable sewage aeration system The drop leg of the system is always made with round pipes. The drop leg is, depending on the actual airflow rate, made with either a DN 80 or DN 100 flange. During design of the system, both the head losses and material cost of the pipes are evaluated in order to select an appropriate pipe size. Piping The manifold is made of either square or round pipes. When disc diffusers are used, a square manifold is used as it is easier to fit on the lateral pipes holding the diffusers. When tube diffusers are used, the manifold can be made of either round or square pipes. This is possible because no lateral pipes are used in this case as tube diffusers are connected directly to the manifold. Wall guide The wall guide supports the drop leg during operation of the system. It is designed as a square pipe, open on one side, with a widening at the top. This widening makes it easier to download the aeration skid during installation or reinsertion after maintenance. TM Product description TM TM Fig. 15 Wall guide 19

20 7 Sewage aeration systems Product description Bottom guide The V-shaped bottom guide is fixed to the tank floor during installation of the system. The bottom guide helps the system to be correctly positioned when lowering the skid into a tank filled with wastewater. Furthermore, the guide prevents the aeration skid from making lateral movements that could otherwise be caused by the liquid flow if mixers or flowmakers are used in the tank. Fig. 16 Bottom guide Buoyancy Buoyancy of the system is controlled in two ways in order to keep the aeration skid at the bottom of the tank. Firstly by the weight of the stainless steel skid supporting the diffusers and secondly by adding counterweight. The counterweight is integrated directly into the beam where also the feet for levelling the aeration system are mounted. An excess weight compared to the buoyant force of the system is used to ensure that the skid stays in place and that no extra strain is put on the flange connection at the top of the drop leg. TM TM Fig. 17 Buoyancy 20

21 Sewage aeration systems 8 8. Performance curves and technical data Curve conditions The curves on pages 22 to 30 are subject to these guidelines: Standard Oxygen Transfer Efficiency (SOTE) is calculated at water levels of 3, 4 and 5 m. Diffuser active surface of 5 % (at a higher active surface, higher SOTE can be reached). Nominal design flow. Airflow per diffuser is listed below each curve. For different working conditions, please contact Grundfos. How to read the performance curves Standard Oxygen Transfer Efficiency Water level above diffuser Performance curves and technical data SOTE m 4 m 3 m 15 Fig. 18 Performance curves Nm³/h Airflow per hour at 0 C and bar TM

22 8 Sewage aeration systems Performance curves and technical data Disc diffuser 9", fine bubble diffuser (1-1) SOTE m 4 m 3 m Nm³/h TM Pos. Description 1 Holder 2 Retainer ring 3 4 Anti-friction ring TM Dimensions Material D1 D2 SAD.F.9.D.A.EP /4" NPT male H1 H2 H3 standard optional perforation Number of perforations Active surface [m 2 ] Holder Retainer ring Anti-friction ring SAD.F.9.D.A.EP EPDM EPDM/silicone, silicone > Polypropylene Polypropylene POM Performance Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.9.D.A.EP At design airflow and 4 m submerged Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound SAD.F.9.D.A.EP > > Shore A < 10 22

23 Sewage aeration systems 8 Disc diffuser 9", fine bubble diffuser ( ) SOTE m 4 m 3 m Nm³/h TM Performance curves and technical data Pos. Description 1 Holder 2 Retainer ring 3 4 Anti-friction ring TM Dimensions Material D1 D2 SAD.F.9.D.A.EP /4" NPT male H1 H2 H3 standard optional perforation Number of perforations Active surface [m 2 ] Holder Retainer ring Anti-friction ring SAD.F.9.D.A.EP EPDM EPDM/silicone, silicone Polypropylene Polypropylene POM Performance Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.9.D.A.EP At design airflow and 4 m submerged Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound SAD.F.9.D.A.EP > > Shore A < 10 23

24 8 Sewage aeration systems Performance curves and technical data Disc diffuser 12", fine bubble diffuser ( ) SOTE m 4 m 3 m Nm³/h TM Pos. Description 1 Holder 2 Retainer ring 3 4 Anti-friction ring TM Dimensions Material D1 D2 SAD.F.12.D.B.EP ISO G 3/4" male H1 H2 H3 Performance standard optional perforation Number of perforations Active surface [m 2 ] Holder Retainer ring Anti-friction ring SAD.F.12.D.B.EP EPDM Silicone > Polypropylene GRPP GRPP Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.12.D.B.EP At design airflow and 4 m submerged Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound SAD.F.12.D.B.EP < Shore A < 10 24

25 Sewage aeration systems 8 Disc diffuser 5", coarse bubble diffuser SOTE m 4 m 3 m Nm³/h TM Performance curves and technical data Pos. Description 1 Holder 2 Retainer ring 3 4 Anti-friction ring TM Dimensions Material D1 D2 SAD.C.5.D.A.EP /4" NPT male H1 H2 H3 Performance standard optional perforation Number of perforations Active surface [m 2 ] Holder Retainer ring SAD.C.5.D.A.EP. EPDM ABS ABS - Anti-friction ring Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.C.5.D.A.EP At design airflow and 4 m submerged Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound SAD.C.5.D.A.EP

26 8 Sewage aeration systems Performance curves and technical data Tube diffuser 2", fine bubble diffuser (1-1.5) SOTE m 4 m 3 m Nm³/h Curve chart is shown at a diffuser length of 1 m TM TM Dimensions Material D1 SAD.F.2500.T.B.EP (2") 500 ISO G 3/4"female SAD.F.2750.T.B.EP (2") 750 ISO G 3/4" female SAD.F T.B.EP (2") 1000 ISO G 3/4" female L1 D2 standard optional perforation Number of perforations Active surface [m 2 ] SAD.F.2500.T.B.EP SAD.F.2750.T.B.EP EPDM Silicone SAD.F T.B.EP Diffuser body Polypropylene Performance Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.2500.T.B.EP SAD.F.2750.T.B.EP SAD.F T.B.EP At design airflow and 4 m submerged 54.0 Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound 1.7 > > Shore A - 26

27 Sewage aeration systems 8 Tube diffuser 2", fine bubble diffuser (2-2) SOTE m 4 m 3 m Nm³/h Curve chart is shown at a diffuser length of 1 m TM TM Performance curves and technical data Dimensions Material D1 SAD.F.2500.T.B.EP (2") 500 ISO G 3/4" female SAD.F.2750.T.B.EP (2") 750 ISO G 3/4" female SAD.F T.B.EP (2") 1000 ISO G 3/4" female L1 D2 standard optional perforation Number of perforations Active surface [m 2 ] SAD.F.2500.T.B.EP SAD.F.2750.T.B.EP EPDM Silicone SAD.F T.B.EP Diffuser body Polypropylene Performance Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.2500.T.B.EP SAD.F.2750.T.B.EP SAD.F T.B.EP At design airflow and 4 m submerged Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound 1.7 > > Shore A - 27

28 8 Sewage aeration systems Performance curves and technical data Tube diffuser 3", fine bubble diffuser (1-1) SOTE m 4 m 3 m Nm³/h Curve chart is shown at a diffuser length of 1 m TM TM Dimensions Material D1 SAD.F.3500.T.A.EP (3") 500 3/4" NPT male SAD.F.3750.T.A.EP (3") 750 3/4" NPT male SAD.F T.A.EP (3") /4" NPT male L1 D2 standard optional perforation Number of perforations Active surface [m 2 ] SAD.F.3500.T.A.EP SAD.F.3750.T.A.EP EPDM Polyurethane SAD.F T.A.EP Diffuser body PVC Performance Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.3500.T.A.EP SAD.F.3750.T.A.EP SAD.F T.A.EP At design airflow and 4 m submerged 31.0 Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound 2.5 > > Shore A < 15 28

29 Sewage aeration systems 8 Tube diffuser 3", fine bubble diffuser (2-2) SOTE m 4 m 3 m Nm³/h Curve chart is shown at a diffuser length of 1 m TM Performance curves and technical data TM Dimensions Material D1 SAD.F.3500.T.A.EP (3") 500 3/4" NPT male SAD.F.3750.T.A.EP (3") 750 3/4" NPT male SAD.F T.A.EP (3") /4" NPT male L1 D2 standard optional perforation Number of perforations Active surface [m 2 ] SAD.F.3500.T.A.EP SAD.F.3750.T.A.EP EPDM Polyurethane SAD.F T.A.EP Diffuser body PVC Performance Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.F.3500.T.A.EP SAD.F.3750.T.A.EP SAD.F T.A.EP At design airflow and 4 m submerged 31.0 Average thickness Tear strength [kg/cm 2 ] Elongation Shear strength [kg/m] Hardness Plasticiser content in EPDM compound 2.5 > > Shore A < 15 29

30 8 Sewage aeration systems Performance curves and technical data Tube diffuser, coarse bubble diffuser SOTE m 4 m 3 m Nm³/h Curve chart is shown at a diffuser length of 606 mm TM TM Dimensions Material Performance L1 D1 W1 H1 Connection SAD.C.2606.T.A.SS ISO G 3/4" male Material Diameter of holes (upper row) Diameter of holes (lower row) SAD.C.2606.T.A.SS Stainless steel AlSi 304 or 316L 4 8 Nominal airflow per diffuser Nominal airflow Maximum airflow Minimum airflow Head loss 1 [cmwc] SAD.C.2606.T.A.SS At design airflow and 4 m submerged 30

31 Sewage aeration systems 9 9. Accessories s Description Material Product number 9" (1-1) for disc diffuser EPDM " ( ) for disc diffuser EPDM s for other diffusers or of different material are available on request. For more information, contact Grundfos. Accessories Diffusors Description Material Product number Body diffusers PP 9" ( ) PP Body diffusers PP 9" (1-1) PP Non-return valve PVDF/POM Nipple for tube diffusers AlSi 304 3/4" male AlSi Anti Friction ring POM 9" POM Retainer ring diffusers PP 9" PP O-ring for saddle clamp D110 EPDM O-ring for 9" diffuser, for use with extra non return valve EPDM O-ring for 12" diffuser, for use with extra non return valve EPDM O-ring for saddle clamps D60.3, D76.1 and D88.9/90 EPDM Supports Description Material Product number Anchor bolt mech. M10 x 80 AlSi 316 AlSi Anchor bolt mech. M12 x 110 AlSi 316 AlSi Anchor bolt mech. M16 x 145 AlSi 316 AlSi Supports AlSi 304 D L=290 mm AlSi Supports AlSi 304 D L=220 mm AlSi Supports AlSi 304 D L=220 mm AlSi Supports AlSi 304 D L=290 mm AlSi Supports AlSi 304 D L=290 mm AlSi Supports AlSi 304 D60.3 L=220 mm AlSi Supports AlSi 304 D76.1 L=220 mm AlSi Supports AlSi 304 D90 L=220 mm AlSi Supports D L=290 mm AlSi 316 AlSi Supports D L=290 mm AlSi 316 AlSi Supports D L=290 mm AlSi 316 AlSi Supports D L=290 mm AlSi 316 AlSi Supports D L=290 mm AlSi 316 AlSi Supports D60.3 L=290 mm AlSi 316 AlSi Supports D76.1 L=290 mm AlSi 316 AlSi Supports D90 L=290 mm AlSi 316 AlSi Purge Description Material Product number Manifold purge pipe PVC Manual purge kit PVC, cpl. PVC Permacap purge kit EPDM/PVC Purge hose EPDM/AlSi

32 9 Sewage aeration systems Accessories Connections Description Material Product number End Cap PP D110 PVC Clamp connection D110 PP Clamp saddle D110, O-rings PP-AlSi Clamp saddle D AlSi 316 nuts and bolts, O-rings PP-AlSi Clamp saddle D AlSi 316 nuts and bolts, O-rings PP-AlSi Clamp saddle D AlSi 316 nuts and bolts, O-rings PP-AlSi Clamp saddle D AlSi 316 nuts and bolts, O-rings PP-AlSi Connection joint for SS pipes D114.3 AlSi Connection joint for SS pipes D168.3 AlSi Connection joint for SS pipes D219.1 AlSi Connection joint for SS pipes D26.9 AlSi Connection joint for SS pipes D33.7 AlSi Connection joint for SS pipes D60.3 AlSi Connection joint for SS pipes D76.1 AlSi Connection joint for SS pipes D88.9 AlSi Gasket D110 quick connection EPDM Gasket with centre RF D90 x 28 x 40 x 5 EPDM Ø40 EPDM Kit 3/4" connector 2" tube diffusers 100 x 100 pipe AlSi Kit 3/4" connector 2" tube diffusers 80 x 80 pipe AlSi Kit 3/4" connector 3" tube diffusers 100 x 100 pipe AlSi Kit 3/4" connector 3" tube diffusers 80 x 80 pipe AlSi Reduction PVC M-F 1" x 3/4" PVC ABS stub D110 for PVC pipes D110 (connection between pipes) ABS Connection for disc diffuser to be glued on laterals. PVC Other accessories Description Material Product number Service tool disassembly 9" retainer ring workshop tool kit Service tool disassembly 12" retainer ring workshop tool kit Service tool assemblyt90 tool

33 Sewage aeration systems Further product documentation WebCAPS WebCAPS is a Web-based Computer Aided Product Selection program available on WebCAPS contains detailed information on more than 220,000 Grundfos products in more than 30 languages. Information in WebCAPS is divided into six sections: Catalogue Literature Service Sizing Replacement CAD drawings. Further product documentation Catalogue Based on fields of application and pump types, this section contains the following: technical data curves (QH, Eta, P1, P2, etc.) which can be adapted to the density and viscosity of the pumped liquid and show the number of pumps in operation product photos dimensional drawings wiring diagrams quotation texts, etc. Literature This section contains all the latest documents of a given pump, such as data booklets installation and operating instructions service documentation, such as Service kit catalogue and Service kit instructions quick guides product brochures. Service This section contains an easy-to-use interactive service catalogue. Here you can find and identify service parts of both existing and discontinued Grundfos pumps. Furthermore, the section contains service videos showing you how to replace service parts. 33

34 Sewage aeration systems Further product documentation Sizing This section is based on different fields of application and installation examples and gives easy step-by-step instructions in how to size a product: Select the most suitable and efficient pump for your installation. Carry out advanced calculations based on energy, consumption, payback periods, load profiles, life cycle costs, etc. Analyse your selected pump via the built-in life cycle cost tool. Determine the flow velocity in wastewater applications, etc. Replacement In this section you find a guide to selecting and comparing replacement data of an installed pump in order to replace the pump with a more efficient Grundfos pump. The section contains replacement data of a wide range of pumps produced by other manufacturers than Grundfos. Based on an easy step-by-step guide, you can compare Grundfos pumps with the one you have installed on your site. When you have specified the installed pump, the guide will suggest a number of Grundfos pumps which can improve both comfort and efficiency. CAD drawings In this section, it is possible to download 2-dimensional (2D) and 3-dimensional (3D) CAD drawings of most Grundfos pumps. These formats are available in WebCAPS: 2-dimensional drawings:.dxf, wireframe drawings.dwg, wireframe drawings. 3-dimensional drawings:.dwg, wireframe drawings (without surfaces).stp, solid drawings (with surfaces).eprt, E-drawings. WinCAPS WinCAPS is a Windows-based Computer Aided Product Selection program containing detailed information on more than 220,000 Grundfos products in more than 30 languages. The program contains the same features and functions as WebCAPS, but is an ideal solution if no internet connection is available. WinCAPS is available on DVD and updated once a year. Fig. 19 WinCAPS DVD Subject to alterations. 34