A Below-Grade Pig Launcher Design

Romtec Utilities designs and supplies package lift stations that frequently include components for pigging. Many times, customers are not familiar with this practice. Pigging is the process of cleaning a force main or pipeline by forcing an object called a “pig” through the pipe with hydraulic pressure. As the pig moves through the force main, it pushes built up solids out of the pipe. Pigging is beneficial to every major water type, and it includes several design considerations and potential component configurations.

In wastewater, solids can build up in the force main over time. This buildup causes several problems, including a decrease in pumping efficiency and increased power consumption. Periodic pigging of the force main in a wastewater system can dramatically improve the function and condition of the system.

Industrial pump stations use pigging frequently. There are numerous reasons for pigging in industrial processes such as using the same pipe for different liquids or removing reactive chemicals. Depending on the process, pigging in industrial applications can happen weekly, daily, hourly, or at any other needed frequency.

For clean water, mineral deposits in the force main can lead to high concentrations of water contaminants. This can negatively affect the water quality for an entire community. Mineral deposits happen slowly over time, but including a method for pigging is very valuable to maintaining a clean water system.

Stormwater collects a lot of solids from runoff that can restrict a force main. Most stormwater systems will benefit from annual pigging after the storm season. This practice essentially provides a clean system for every rainy season. Pigging can help prevent clogging from occurring over time or as the result of a storm event.

The first design consideration for pigging is the access point to the force main. This access point can be designed as a pigging port or a pig launcher. For most pump stations, a pigging port will be the most affordable and functional option. This port forks from the force main with the same diameter and a flange on the end. A water hose will connect to the flange or to a separate inlet to supply hydraulic pressure for pigging. The second option is a pig launcher. These are separate pipes with valves and additional components that connect to the force main. A pig launcher can use hydraulic pressure from the system itself or a fire hose equivalent to insert the pig into the force main. A pig launcher allows the pump station to function normally while pigging takes place.

The next aspect of pigging also needs to be addressed in the design and engineering phase of a lift station, force main, or pipeline. Any valve that is located downstream from the pigging port or pig launcher must have a 100% pipe diameter opening. Pigs are sold with diameters to match the force main ID; a valve that restricts the force main diameter in any way will result in the pig becoming stuck. It is important to specify these details if separate firms are designing and installing valves and pipes on the force main or pipeline.

The final element of pigging is the pig. Most pigs today are relatively inexpensive and designed for very specific purposes. Pigs can have abrasive “skins” that scrub solids from the force main, or they can use flexible rubber rings that gently push solids in front of the pig. There are also “intelligent” pigs that measure conditions inside the force main such as the thickness of the pipe wall or the presence of leaks. Pigs are available with specific designs for wastewater, clean water, or any type of industrial water.

Depending on the needs of the company, city, or utility district, pigging can be accomplished with a new pump station through a number of scenarios. Romtec Utilities has designed countless pump stations with pigging capabilities, and can help your organization include this feature in a new package lift station. For more information on pigging, contact Romtec Utilities by calling (541) 496-9678.

A Rosemount Radar Level Transmitter

Romtec Utilities can include a lot of design options in a packaged pump station. Level sensing can be one of the most vital components during pump station engineering, and many operators and engineers have passionate opinions about which option works the best. Romtec Utilities designs its packaged pump stations to meet the needs and expectations of its owners and operators no matter which method they prefer. Each method of level sensing offers distinct advantages, and Romtec Utilities is happy to recommend a level sensing device that will benefit your unique system.

Floats

There are a few basic types of floats. Mechanical floats actuate a switch that is triggered as the float tips from vertical to horizontal. Magnetic floats operate similarly. A magnet on the float pushes a magnet on the switch mechanism with the same polarity. As the float tips horizontal, the polarity pushes the switch to complete an “on” circuit. The “off” circuit is completed as the switch and float return vertical. Mercury floats use mercury to complete a circuit. Mercury flows between to contacts as the float tips allowing an electric signal to pass to the lift stations controls. Environmental regulations in many states do not allow mercury floats.

Floats are almost always the lowest costs solution for level sensing. They are easy to adjust and replace, and additionally, floats can be visually inspected for maintenance purposes. Floats can either be counter weighted to the specific gravity of effluent or tethered to a substrate. The use of floats is limited because they must be submerged in the liquid being measured, meaning corrosive, abrasive, incongruent, or overly-viscous liquids can create maintenance or operation problems.

Probes

Like floats, conductive probes are suspended into the wet well and make contact with the effluent. Probes utilize a series of contact points that transmit a small current as the effluent fills the wet well. The lift station controls initiate a response as each set of contact points is triggered. Even though probes utilize an electrical current that makes contact with the effluent, they can operate with an intrinsically safe barrier. Intrinsically safe barriers allow the probe to operate with such small electrical currents that the liquids and gasses in the wet well are in no danger of combusting.

Probes cost more than floats by provide a durable solution. Probes are not typically affected by turbulence or grease and debris build up. Probes are typically easy to install and maintain because they can be visually inspected for build-ups. In clean water or food processing pumping applications, probes contain no harmful elements such as mercury that could possibly contaminate a system, making probes environmentally friendly.

Pressure Transducers

Pressure transducers operate on a basic mathematic assumption. If you know the liquid that is being collected and you know the size of your wet well, you can easily figure out the pressure at each depth mark in the well. The pressure transducer uses a diaphragm to measure the pressure of the liquid in the wet well and assumes its corresponding depth. The pressure transducer can in this way relay information to the lift station controls to execute the appropriate actions.

Pressure Transducers are extremely accurate and can be adjusted to keen detail. Pressure transducers also require computation to function, so this means of level sensing is an excellent choice for adding redundant lift station controls. Pressure Transducers are also very robust units that typically don’t require a lot of maintenance.

Ultrasonic Transducers

With proper maintenance, the ultrasonic transducer is a reliable and robust level sensing devise. Ultrasonic sensors do not make contact with effluent, making wear and tear a small concern. Ultrasonic sensors work by sending out high-frequency sound waves that create, in effect, an echo off the surface of the liquid in the wet well. The sensor then measures the time gap between sending the signal and receiving its echo. This time gap is directly proportional to the distance from the sensor to the level of the liquid in the wet well.

This sensor can be extremely accurate, but it does require proper maintenance. The device itself is pretty failsafe, but foam, cobwebs, dust/mist, and other impediments can affect the normal functions of the device. To a large extent, these concerns can be eliminated by selecting Ultrasonic sensors for specific water types, but as long as operators are aware of the issues, these devices perform well for extended periods of time. Ultrasonic transducers do require a clear field of view to the water surface, so the lift station engineering must understand the viewing range of the device and keep that space clear of hardware.

Bubblers

Bubbler systems have been in use for a long time, and some operators swear by them while others consider them outdated. An air compressor outside of the wet well pumps air through a “dip tube” that goes to the bottom of the wet well. This first part is true of all bubbler systems, and the air issuing from the dip tube is where the name bubbler is derived. As the wet well fills, the compressor must pump more air to maintain the bubble stream. Another air tube stems off from the dip tube and can hook up to several different devices. One device that was mentioned above is the pressure transducer. In this scenario, the transducer measures the air pressure increase as the wet well fills. Another measuring device uses the air pressure to push mercury up a tube like a thermometer. As mercury rises with the air pressure, it touches contact points that complete relay circuits.

Bubbler systems are a simple technology that is time-tested and has been proven to work under many conditions. The dip tube needs to be checked for build up and potential blockages that could misrepresent the pressure in the wet well. These systems are typically used in wastewater applications and can have accuracy issues in other water media such as slurry and corrosive liquids. Some bubbler systems will experience high installation costs because most of the system is  located outside of the wet well and needs a separate storage structure.

Radar

Radar sensors operate in a similar way to the ultrasonic transducers. The difference is that radar devices utilize radio waves instead of sound waves to create an echo or in this case a wave reflection. Radar devices have the broadest range of use with different water types, and they are not generally affected by changing viscosities, pH, pressure, temperature, density, etc.  Radar devices do not require heavy maintenance, and can even be programmed to ignore objects in their field of view. This means that the lift station engineering does not have to provide a 100% clear field of view for this device, making simplified configurations possible.

Radar is typically one of the most expensive devices at installation; however, the lifetime operation and maintenance costs are lower and can repay the investment with time. These devices are extremely smart. They do not require recalibration often and can utilize their operating systems for primary or redundant lift station controls.

Within each category of level sensing device, there are many models and options in order to provide a device specific to the water type and design of each packaged pump station. There are many considerations when selecting a level sensing device, and Romtec Utilities is happy to recommend an appropriate device for your system. Romtec Utilities also understands that experience and comfort level with a device is extremely important. We will always honor a customer’s request for a preferred device and design a functional and cost effective packaged pump station with their preferences in-tact. Please contact the Romtec Utilities sales staff with any questions you might have on level sensing devices or any other query about lift station engineering.

Example Plans for a Lift Station Replacement

Lift Station owners and operators throughout the water and wastewater industry are well aware of the increasing pressures being placed on aging infrastructure.  According to the Water Infrastructure Network, over $40 billion dollars in ready-to-go water and wastewater projects existed last year.  Romtec Utilities works with industry personnel everyday to upgrade lift stations across the country, and we believe that any owner or operator working with aging lift stations should be aware of their options for improving their systems. The key to a successful upgrading project will begin by indentifying what type of project it is. This is where to decide if your lift station upgrade is one of these 3 Rs: repair, retrofit, or replacement.

Lift Station Repair

Lift station repairs will typically solve minor problems and won’t require a new lift station design. The day-to-day operation of the system will typically be maintained while repairs are taking place. Lift Station repairs will generally fix a failing component of the entire system, like adding grinder pumps to an otherwise functional  wastewater lift station or updating the control panel to include SCADA (Supervisory Control And Data Acquisition) capabilities.

For many lift stations in clean water, stormwater, and wastewater, lift station repairs can add years to the life cycle of a pump station system. It is important to evaluate the entire lift station engineering before undergoing a lift station repair. This will ensure that new components will be compatible with existing systems and that down time for the system can be minimized or eliminated.

Lift Station Retrofits

To Romtec Utilities, a lift station retrofit is a complete overhaul of a failing or out-of-date system. In a retrofit scenario, the first step is to inspect the complete pump station to evaluate which components can be retained throughout the retrofit. Typically, the wet well is the primary piece to determining if a lift station retrofit can take place. A healthy wet well can save large amounts of time and money in engineering, manufacturing, and installation costs.

Retrofitting a lift station goes beyond simply swapping the pieces. A good lift station retrofit will upgrade system components to the current industry standards with complete lift station design and engineering. A lift station retrofit will only be successful if it ensures a functional system, utilizes existing components, and saves time and money over a lift station replacement.

Lift Station Replacement

A lift station replacement is a straightforward procedure in some ways, but there are considerations that should be made before undertaking this type of project. Pump stations are typically not designed for any downtime. Considering this premise, how do you remove and install a lift station without shutting off the system?

Rotmec Utilities recommends that a new lift station replacement be installed adjacent to the existing system if the property size permits such construction methods. At Canyon de Chelly in Arizona, the Navajo Nation and National Park Service were able to replace an existing system in this manner. The new system was constructed and “tapped” in to the existing inlet line and discharge force main. When the replacement system was started up, it simply overtook influent from the existing lift station, allowing the existing system to be retained for emergency purposes.

At Goleta Beach in California, the County of Santa Barbara operates a pump station with a much smaller footprint (that is to say property). At this site, construction of an adjacent system would have been impossible. Bypass pumping was utilized during the removal of the existing lift station and the construction of the lift station replacement. It is important to have precise lift station engineering and construction/start-up schedules when using bypass pumping during a replacement.

It can be difficult to determine which method is the best to upgrade an aging lift station. These systems are almost always underground and cannot simply be visually inspected. System owners can often save a lot of time and money if existing lift stations are evaluated correctly early on. Contact Romtec Utilities about your project and begin the investigation process to see which of the “3 Rs” will work for your clean water, stormwater, or wastewater lift station.

The Detention Pond and Pump Station at the East Campus Facility

Romtec Utilities recently completed a large project for the Sacramento Municipal Utility District (SMUD) at the new East Campus Operations Center that is currently under construction. The Romtec Utilities supply included a wastewater lift station and a large stormwater pumping station.  These two packaged pump stations are a part of construction that began on this facility in September of 2011. Each package pump station offers tremendous benefits for the East Campus facility, which is a champion of green building design and energy efficiency.

At the heart of this project is green building design, environmental impact, and energy efficiency. These were the key areas of focus when SMUD decided to add a new 51-acre office and utility complex. The design included a six-story corporate office building, several low-rise structures for various uses, a large equipment and storage yard, and a large solar array incorporated into the parking. In order to make all of this construction possible, the site needed to have reliable and effective stormwater and wastewater pump stations.

When designing facilities for Leadership in Energy and Environmental Design (LEED) certification, a major consideration is planning for stormwater events. A facility like the East Campus Operations Center includes impervious surfaces like the parking lot, the building roofs, the vehicle maintenance and fueling sites, and more. These surfaces do not allow stormwater to be absorbed naturally by the soil. Additionally, as stormwater flows across the impervious surfaces, it collects contaminants and minerals that can be harmful to the ecosystems of natural waterways, i.e. streams, ponds, or rivers.

Large stormwater events can create hazardous environmental conditions as contaminants rush into unprepared ecosystems. Collecting stormwater and treating it to remove contaminates is one solution to negate the impact of impervious surfaces with regards to stormwater. Including a system to accomplish this is important for an environmentally friendly and certified facility. Romtec Utilities designed, supplied, and started-up a large stormwater pump station to exceed the stormwater expectations of the East Campus facility. But at this facility, there were more than just environmental considerations for designing a stormwater pump station of this size.

The East Campus facility is located on a plot that is essentially a giant depression. The land was purchased from a past gravel quarry which had scraped down the top soil during years of business. The result was a manmade lakebed waiting for rain. SMUD was building in a large critical path for flooding, and the options were to either raise the elevation for 59-acres or to prevent critical amounts of water from collecting. The Romtec Utilities supplied pump station would accomplish the latter.

The stormwater pump station was a no-fail proposition, not only for the benefit of the environment but for the protection of the facility as well. Romtec Utilities engineered this pump station in a triplex configuration to ensure its continual operation. That means that this station included three pumps in the wet well. With a triplex configuration, the pumps will cycle between one or two pumps operating at a time with the third pump standing-by in case a pump fails. The lift station controls will cycle starts between the three pumps to maintain equal operation times. This prolongs the lifespan of the pumps while decreasing wear and maintenance requirements.

A unique feature of this stormwater lift station was the variable frequency drives (VFDs) for the pumps. Pump stations are essentially collection basins with pipes that bring water in and pipes that take water out, and each has its limitations. For this system, there was a maximum of 8500 gallons per minute that could be handled by the downstream system, i.e. treatment, force main, etc. The VFDs limited the output of the pumps so that when two were working in tandem they did not exceed pumping 8,500 gallons per minute, which was the limit of the system. The station was engineered this way so that one pump could meet the needs of typical stormwater events when operating at full power but so that two working together would not overstress the system.

Another aspect to designing a facility this large is managing the outflows that over 750 SMUD employees generate. The location of the East Campus facility required a sewage lift station to pump wastewater from the facility to gravity lines to the municipal treatment. Romtec Utilities designed a duplex lift station with two, 15HP Ebara submersible sewage pumps. This wastewater lift station included simple alternator lift station controls with Anderson floats for level sensing. The wet well is over 25 ft deep with a separate dry pit valve vault.

SMUD was able to get an economical lift station with a number of failsafe components to protect the environmental certification for the facility. Together, the two Romtec Utilities supplied pump stations accomplished the goals of SMUD by providing durable, dependable, cost-effective, and environmentally friendly water infrastructure for the East Campus Operations Center.

The Romtec Utilities portion of the $111 million-dollar project was one of the initial construction phases at the East Campus. The total project should be completed by fall of 2013. This project is great example of a governmental agency constructing modern and environmentally conscientious facilities while managing costs responsibly.

For more information on SMUD, click here.

For more information on the East Campus Facility, click here.

To see Romtec Utilities’ stormwater pump stations, click here.

To see Romtec Utilities’ wastewater lift stations, click here.

Staging the wet wells before installation.

In the final part of this blog series, we will look at the biggest industrial stormwater system in this series: the Chalmette refinery in Louisiana. Chalmette Refining, LLC is a joint ownership venture between ExxonMobil and Petròleos de Venezuela. Romtec Utilities supplied a very unique stormwater pump station capable of servicing the entire refining facility.

ExxonMobil and Engineering and Inspection Services, LLC. (EIS) came to Romtec Utilities to help them solve a problem. The Chalmette Refining plant had an aging stormwater pump station that needed to be replaced. ExxonMobil and EIS chose precast concrete as the preferred method for installing a new sump, but a precast structural member that large was challenging. They did not find a willing designer for the 6,500 cubic feet rectangular sump until they contacted Romtec Utilities.

Romtec Utilities’ engineers also recognized the difficulties for the specified precast component, so they chose to engineer and propose a different approach. The new design broke up the sump into three separate precast rectangular vaults. Each vault was connected by four large pipes at the bottom and top of the adjoining walls. The new design would function just like a single precast vault, but it provided a much more reliable sump component.

The precast sumps were fitted with all the spools, fixtures, hatches, connective piping, pump mounts and bolts, and electrical grounding plates during the prefabrication. Another unique element during this stage was a giant stainless steel baffle prefabricated into place in front of the inlet line. The existing inlet line for this system was specified at 48 inches ID and would deliver 30,000 gallons per minute of stormwater.  The amount of force generated by such a large flow of incoming stormwater needed to be minimized to protect the submersible pumps and other wet well fixtures. The large baffle would slow the water inflow and direct the flow toward three submersible pumps.

Two submersible pumps were housed in the first stage rectangular wet well and the third submersible pump was located in the front of the second stage wet well. Behind this pump was a 15-foot-tall retaining weir wall that contained the dirtiest water with the submersible pumps. If water levels climb above the weir wall, the water spills over into the rest of the second stage wet well and can flow into the entire third stage as well.

On the far side of the retaining weir wall, two vertical turbine pumps were in second stage wet well and three additional turbine pumps were located in the third stage wet well.   To summarize, three stages of connected rectangular sumps were split into two divisions. The first division used three submersible pumps and the second division used five vertical turbine pumps.

This design was chosen for a few reasons. Submersible pumps are more capable of pumping gritty and turbid water, making a preferable first line of defense. The eight total pumps do not pump to the same location. This pump station discharges to several different holding tanks where the water is pumped via a separate system to an on-site oil/water separator. The Romtec Utilities station preserved the existing holding tank discharge priority. The entire precast pump station was placed inside of the existing sump and backfilled with concrete slurry.

The Romtec Utilities and EIS design allowed ExxonMobil to utilize several pumps that it had in stock. EIS and ExxonMobil chose to use Chalmette Refining staff to install electrical components and system controls. Romtec Utilities acted as a consulting agency to assist ExxonMobil and EIS develop the control system for level sensing to start and stop the pumps and to control the order in which the pumps proceeded.

This industrial stormwater pump station is as large as it is sophisticated. Romtec Utilities was able to engineer a package pump station capable of meeting the requirements of ExxonMobil and EIS. Romtec Utilities also worked to develop plan that would allow ExxonMobil and EIS to manage specific aspects of the system like the pumps, radar level sensing, and system controls. This approach led to a fully functional pump station that met all requirements and provided substantial financial savings to ExxonMobil.

This industrial stormwater blog series covered seven unique and interesting projects that Romtec Utilities completed. Industrial companies deserve credit for their efforts in environmental responsibility with stormwater. This series sought to showcase their efforts. Romtec Utilities supplied each of these companies with a functional and sophisticated system that will manage their stormwater for decades to come.

Base Slab Installation

Part seven of this industrial stormwater blog series looks at an interesting plot of land for the Tesoro Corporation. The Tesoro facility required a stormwater plan because of its unique location on a narrow peninsula in the Salish Sea. Tesoro worked with Tulsa Engineering Alliance to engineer an oil/water separator with an accompanying package stormwater pump station from Romtec Utilities.

The pump station was fairly straightforward for an industrial job. Collected stormwater from the facility is drained into an oil/water separator first. After oil separation, the water drains into the Romtec Utilities pump station where it is pumped to the Crown Sewer Treatment Plant. This preliminary treatment ensures consistent water chemistry, eliminating a major concern for lift station engineering.

The station itself is less than 8 feet deep and includes two, Ebara submersible pumps in a duplex configuration. The system valves were contained within the wet well, and a drop bowl was included to reduce turbulence in such a small sump. Level sensing was engineered with NOLTA floats, which are suited for small containers. The pedestrian rated hatch offered easy access to the in-well system components for inspection and maintenance. This design is uncomplicated because the water chemistry and flow rates are so consistent.

The interesting aspect about this pump station is the unique location. The Tesoro facility is fundamentally a transfer site for offloading refined fuels from cargo ships into large holding tanks. The fuel is then dispersed for distribution from these tanks. The facility is located on a peninsula that is less than 150-feet-wide, with shoreline into the Salish Sea on both sides. Containing the total stormwater from the facility was an essential environmental consideration.

The seven holding tanks, ranging from about 20 to 80 feet in diameter, are surrounded by concrete containment walls and are further divided into drainage sections by concrete curbs. This method of drainage ensures that each section drains to its own catch basin, preventing any one basin from being overcome and flooding. This level of containment is necessary to prevent any significant amount of stormwater from reaching a natural habitat.

Romtec Utilities supplied Tulsa Engineering with only the structural and mechanical components in the system package. Tesoro preferred to use its own staff to implement station controls and electrical engineering. The ability of Romtec Utilities to customize its supply package to the customer’s specifications is really an asset, even on a small system such as this project.

With Romtec Utilities, Tesoro was able to purchase an affordable way to manage the stormwater at this transfer site. Oil and gas companies like Tesoro are working hard to manage their environmental impact, and purchasing a reliable, affordable, and customized Romtec Utilities package lift station is an excellent solution for implementing and managing a stormwater plan.

Next week, we will look at one of the largest stormwater systems ever designed by Romtec Utilities.

In part six of this industrial stormwater blog series, Romtec Utilities worked with Praxair, Inc. and S & B Engineers and Constructors on another addition to a Valero Refinery, this time in Port Arthur, Texas. This project provides an opportunity to demonstrate how Romtec Utilities can design for precise pumping goals when the criteria for stations are essentially the same but with crucial differences.

Recall last week, Praxair and S & B partnered to install a new hydrogen manufacturing plant for use at Valero Energy Corporation’s St. Charles Refinery. Romtec Utilities engineered a pump station to handle multiple inflow rates with constant low flows, “dumps” of high flows, and varying stormwater events. These requirements were met by using a “jockey” pump to manage the low flows and two large submersible pumps to manage the “dumps” and stormwater events.

The Port Arthur plant originally specified an identical pump station to the one at the St. Charles Refinery, but small changes in the pumping goals led to a different proposal by Romtec Utilities. The pumping goals for the Port Arthur pump station specified higher head conditions with higher pressure in the discharge piping. This difference created a problem. The pumping requirements for the large pumps were rare, and rare can also mean expensive.

Romtec proposed self-priming pumps for the large pumps and also for the jockey pump. The benefit of self-priming pumps was that they could meet the pumping requirements for the station at a more economical price than using submersible pumps. Praxair and S & B chose this solution to meet the pumping requirements.

Since the original plan was to have two identical stormwater pump stations, Praxair and S & B decided to self manage installation. The new design with self-priming pumps created a wrinkle in the installation process. Romtec Utilities prefabricated a skid with the three self-priming pumps mounted to it. Creating a single skid pump component made the installation process and instructions much simpler.

The wet well was installed in the same manner as the St. Charles pump station. Once the entire sump structure was complete, that skid mounted pumps were simply piped and set in place, and the entire skid was bolted to the top slab of the sump. This method created a simple process to help Praxair and S & B install the pump station themselves.

This pump station, like the St. Charles pump station, allowed Praxair to meet its pumping goals for not only stormwater but also for process water applications. Industrial companies tend to favor this approach because it simplifies their total systems while providing a pump station capable of handling all stormwater environmental concerns.

Next week, it’s back to the Northwest to Port Angeles, Washington where a new oil/water separator for Tesoro needed a lift station to pump to a treatment plant.

View of the Wet Well at Installation

Last week, a stormwater pump station for Dow Chemical Corporation was discussed in terms of integrating into an existing stormwater system. Today in part five of the industrial stormwater blog series, we’ll look at a deeper level of stormwater pump station integration for an expansion to the Valero St. Charles Refinery.  Romtec Utilities collaborated with Praxair, Inc. and S & B Engineers and Constructors to design this combination stormwater and process water pump station.

Praxair is primarily a manufacturer of industrial gases. Contracting with Valero Energy Corporation, Praxair agreed to expand Valero’s St. Charles Refinery with a large hydrogen manufacturing plant. Hydrogen is used in refineries to produce “green” diesel. An important aspect of new industrial construction is creating a stormwater plan. Praxair, S & B, and Romtec Utilities designed an efficient and economical solution to integrate stormwater and process water into a single packaged pump station system.

To start, the pump station would need to handle a constant low flow of process water. This water is a byproduct of the manufacturing process that needs to be treated before it can be discharged or reused. Next, the pump station would need to handle a much larger flow of process water that would inflow from a “dump” of another manufacturing process. Finally, the station needed to handle stormwater events that would drain into the pump station.

In order to meet the criteria for the pump station, a triplex pump configuration was designed with one pump substantially smaller than the other two. Typically, engineers refer to this smaller pump as a “jockey” pump. In this pump station, the jockey pump never stops working unless a specified low level is detected. The constant small inflow of process water is continually pumped to the refinery’s on-site treatment facility.

When the “dumps” of process water occur or when there is a stormwater event, water in the wet well quickly overcomes the jockey pump’s capability. This will prompt one of the larger pumps to start. The second large pump starts if the water level rises to a specified high level. As the large pumps discharge the high inflows, the jockey pump maintains operation, and when the water level reaches a specified low level, the large pumps stop.

Each pump responds to specified levels of water in the wet well to meet the varying inflow rates. Additionally, the large pumps alternate between starts to balance their operation time, wear, and life cycle.  Romtec designed this pump station with submersible pumps to meet the customer’s specifications.  This system is a terrific example of how expert engineering can place a stormwater pump station within the context of an industrial facility to meet multiple goals.

Next week, we will look at how very small changes in the pump station goals can result in large changes in engineering. We are heading 200 miles west along the Gulf Coast to Port Arthur, Texas for another Praxair construction project.

The Fiberglass Stormwater Wet Well

Part four of this industrial stormwater blog series has us going down to the banks of the Mississippi to the Dow Chemical Company Louisiana Operations in Plaquemine. This facility is gargantuan. Dow actually co-located two of their companies at the same facility, creating a huge manufacturing complex. The facilities produce plastics, solvents, paints, adhesives, cosmetics, detergents, pharmaceuticals, and much more. Romtec Utilities supplied Dow with a fully packaged fiberglass pump station that integrated into an existing stormwater and control system.

The number of products manufactured at the Plaquemine facility is substantive, and many of its products are chemical building blocks used in other manufacturing processes. A lot of these raw chemicals present hazards to the environment if they are not managed responsibly, and even with responsible handling, accidents and forces of nature can create events where environmental contamination is possible.

The location of this facility on the banks of the Mississippi River makes responsible stormwater management very important. Dow contacted Romtec Utilities to design and supply a fiberglass pump station that it could install and integrate into its stormwater system. Many of the large industrial customers follow the same path because they employ staff with expert knowledge of their systems but rely on Romtec Utilities for expert knowledge of individual pump stations.

The solution for this industrial stormwater pump station was truly a packaged system. Romtec Utilities worked with Xerxes, a fiberglass tank manufacturer, to prefabricate the pump station wet well with a large quantity of components installed. These components included the discharge elbows and piping, mounting brackets, entrance hatch, vent pipe, guide rails, conduit ports, and deflector panel.

Using this method of prefabrication eliminated a large amount of work that would need to be done on the job site. It also simplified the installation process so that Dow employees could facilitate installation without needing technical support. When Romtec Utilities sent down its start-up technician, the installation had been completed perfectly and was ready for tests and start-up.

The story of this lift station is two companies working together to maximize human resources and skills. Dow Chemical was able to purchase a packaged stormwater pump station, install it with its own employees, and utilize Romtec Utilities’ expertise in pump station design and supply. The final system is a sophisticated piece of technology that is integrated into Dow’s existing system.

Next week, the blog series travels downriver where Romtec Utilities installed a dual purpose stormwater pump station for Praxair Hydrogen Refinery in St. Charles, Louisiana.

Finishing Installation at the Cherry Point Refinery

According to the Cherry Point Refinery Environmental Policy, Cherry Point recognizes and is committed to the protection and respect of the environment within which the refinery operates. The majority of the refinery’s impervious surfaces drain into the facility’s on-site wastewater treatment center, but part of the refinery was not draining into that system.

The federal permits and requirements as discussed in part one of this series stipulated regulations for wastewater treatment and required stormwater plans for future construction projects larger than one acre. The refinery occupies about 3,300 acres, so installing a large stormwater pump station became an attractive solution. In addition to a stormwater pump station, semi-impervious gravel areas would be resurfaced to drain more effectively and limit the concentration of suspended dirt particles.

Addressing stormwater issues with this approach was a responsible and forward thinking solution to stormwater events at the Cherry Point Refinery. The Cherry Point Refinery is located near two important natural habitats, Birch Bay State Park and the Strait of Juan de Fuca.  It is less than 1000 feet from Terrell Creek, which flows into the park, and less than a mile from the shoreline.

With these prominent recreation areas and habitats nearby, adding a robust pump station lessened any immediate and future concerns for stormwater runoff. Romtec Utilities worked with Jacob’s Engineering out of Bellevue, Washington to design the Cherry Point pump station. Jacob’s engineering supplied Romtec Utilities with information about the job site and the pump station requirements. They also worked directly with the Cherry Point Refinery to establish a clear plan for the pumping goals of the system.

The end result was a submersible pump station in a duplex configuration. Duplex configurations are typically used as a failsafe in case one pump fails during a pumping cycle. With stormwater, an overflow scenario is not the same concern as is it would be with sewage, but the Cherry Point Refinery valued installing a system that would protect the environment even in unlikely circumstances.

This attitude also extended to the system’s level sensing and controls. The primary level sensing device was a set of mechanical floats. The system included backup level sensing with an ultrasonic transducer that was prefabricated into the top slab. The ultrasonic device also served as redundant controls for the pump station. The level of backup systems on this pump station is not typical for stormwater systems, but the BP managers at Cherry Point realized the importance of eliminating possibilities of oil and gas pollution.

With Romtec Utilities, Jacob’s Engineering, and the Cherry Point Refinery, a dependable solution was developed to solve the industrial stormwater concerns at this oil refinery. This is another example of an oil and gas company embracing the modern climate of water infrastructure environmental responsibility.

Next week, we will look at a literally packaged pump station for Dow Chemical.