Squirt Pressurized Drainfield Design Software. Patented

New Squirt video

2012-01-25T20:54:00.001-07:00

Video showing you how to add pumps to Squirt

2012-01-24T20:35:00.000-07:00

How Squirt Uses Pump Coordinates

In order to add a pump to the Squirt pump file you must enter five, head-flow, points using either the "Add Pump" window or the Pump Curve Digitizer. Squirt uses these points to not only define the pump curve but also to enable the Automatic Pump Selection feature, therefore, it is important that you understand the significance of each point.

Zero-Flow Point: This point represents the highest pressure the pump can produce which occurs at a condition of zero flow.

Left Operating Point (LOP): The location of the Left Operating Point(LOP) is determined by the user. Squirt's Auto-Select feature will not display a pump where the System Head-Flow Rate Curve crosses the pump curve to the left of the Left Operating Point. The LOP is therefore a minimum allowable flow rate for that particular pump.

Best Efficiency Point (BEP): The Best Efficiency Point is the point where the pump operates at its maximum efficiency, where loads on the bearings are balanced and where the problem of cavitation is minimized. It is good practice to select pumps that will operate close to their BEP. Larger pumps usually include efficiency curves with the performance curves

Right Operating Point (ROP): The Right Operating Point (ROP) is analogous to the LOP in that it represents the maximum design discharge for the pump. Auto-Select will not select the pump if the system curve crosses the pump performance curve to the right of the ROP.

Maximum Flow Point: This point is maximum flow rate, minimum head, condition for the pump.

When the pump search default tolerance is selected, Squirt will select pumps so that the system curve for the pressure network you are designing falls between the LOP and ROP. If you choose to specify the search tolerance, squirt will select pumps where the system curve is within the specified flow rate or head from the BEP. These concepts are illustrated on the graphs that follow.

Example 1

Example 1 shows a pump curve and system curve with the points described above labeled. Notice that the system curve passes between the LOP and ROP close to the BEP.

The Auto-Select feature selected this pump because it met the tolerance designation in the Pump Selection criteria. The user specified that pumps must be within 15 gpm of the BEP.

The selected pump curve crosses the system curve 14 gpm from the BEP.

2011-12-27T20:32:00.002-07:00

Squirt mentiontioned in Onsite Installer magazine article

2011-12-21T14:46:00.002-07:00

An engineer has a professional responsibility to understand the analysis
tools being used to complete the clients project.

In the most recent issue, Onsite Installer published a short article titled, "Pump to Gravity: Does It Make Sense?" The author of the article suggests that if a pump is necessary to supply the drainfield then it only makes sense to pump to a pressurized pipe network. The article states:
Since the pumping system is there, why not use it to its full advantage? Why not discharge to small-diameter laterals that can provide uniform application of a calculated effluent dose over the entire field? A pump-to-gravity system most likely will not evenly distribute the dose of effluent over the entire drainfield (Machmaier & Anderson, 1987).

I agree with the author regarding the value of utilizing pressure distribution to achieve uniform effluent distribution across the entire infiltrative surface but, if the goal is actually to design a system satisfying this purpose, doesn't it also make sense to select a method of hydraulic analysis capable of determining if this goal has been met?

Answering this question may also provide insight why installers might choose to pump to gravity rather than pressurize the system. A contractor friend of mine told me a story a while ago about his experience with engineers and pressurized drainfields. I thought it was a funny story until I thought about what he was really saying.

This contractor installed many onsite systems and worked with most of the engineering firms in the area. A usual permit requirement was that pressurized systems be field tested to verify a maximum of 10% difference in squirt height. The contractor stated that the 10% requirement caused a lot of problems because most of the designers of these systems could not seem to prepare a design that actually met this condition in the field.

One engineer designed a system that the contractor installed and when they field tested it, the squirt height was not uniform across the piping network. According to the contractor uniformity was not even achieved on individual laterals let alone the entire pipe network. The first thing the engineer did was blame the contractor (This is standard practice, right? I have seen many sets of specifications that place the responsibility for operation squarely in the contractors lap). When the contractor asserted that he built the system exactly as shown on the engineers plans, the engineer called the pump supplier and requested the pump supplier load up every model of pump he had in the warehouse and bring them out to the field so he could squirt test the system with every pump the supplier had. None of the pumps corrected the problem and he should have known that in advance.  Because he was having a uniformity problem, there was no hope of correcting it with a different pump because the problem is not with the pump, it's with the piping system he had designed. The system was buried and the non-compliance was ignored.

Another system, designed by a different firm, was installed on a sloping site. To account for the elevation difference of the site, the engineer called out ball valves at each connection of a lateral with the manifold. He reasoned that it would be a simple field operation to set the squirt height across the piping network by adjusting the ball valves.

Although the system served only a single family residence, it was fairly large due to clayey soils and it quickly became clear that the home owners water well could not keep up with the quantity of water required for testing the system. The engineer was forced to request that water be delivered to the site so they could continue adjusting the drainfield. The contractor had a local ready-mix concrete supplier fill mixers with water and drive them to the site. By the time this little fiasco had wrapped up, the engineers were soaked to the bone and the system had not been "dialed in." It, just like the other one I mentioned, was buried while out of compliance. These are not isolated occurrences; I am aware of many designs, installed according to plan, that simply do not function according to the design. One is compelled to ask, what went wrong? What did these two systems have in common?

The obvious answer is that these pressurized drainfields shared a common problem, they both were designed and built without the benefit of a competent hydraulic analysis. Consider the "ball valve" system. Clearly this system was not subjected to a thorough hydraulic analysis because, had it been, there would be no need for field adjustment of ball valves to control the hydraulics of the system. The ball valves are a means of compensating for an incompetent design.  Even if they had been able to adjust the ball valves to the point where the system discharge was uniform, how can they be sure that the pump is operating near its best efficiency point?

The first system was designed around a set of "rule of thumb" guidelines. Take some orifice diameter, figure an orifice discharge rate, multiply the rate time the number of orifices in the system to obtain a total flowrate. Add the desired residual pressure to the elevation difference between the pump tank and drainfield and Viola!   Instant pressure distribution system design. Too bad it didn't work. The hydraulic profile along the lateral probably looked something like that shown below and surely cannot be confused with uniform distribution.

Lateral hydraulic profile showing non-uniform distribution.

These systems were not inexpensive and the designers/engineers were paid quite handsomely for the design. But by apparently not understanding fluid dynamics, mistakes were made that resulted in non-compliance and perhaps premature failure.

I have seen automatic distribution valves being used increasingly in a vain attempt to avoid a detailed hydraulic analysis. This practice adds initial capital cost for the valve, housing and more complex piping to serve the drainfield. Furthermore, the sequencing mechanism in the valve requires maintenance to avoid the potential problem of the valve locking and directing the entire quantity of wastewater to a single lateral. (When the situation calls for a sequencing valve, I recommend valves manufactured by FIMCO Manufacturing in Jupiter, FL. Fimco valves are fitted with an ingenious indicator on the sequencer that allows the O&M provider to easily inspect the operation of the valve)

I think the system designers are largely responsible for contractors and homeowners installing what might be considered less than perfect systems. This is because so many designers do not know how to correctly calculate the hydraulic response of the system and/or have placed blind faith in sales tools disguised as analysis programs or hand-me-down spreadsheets that cannot account for design criteria such as minor losses, elevation differences, differing lateral length or alternate manifold configurations. (In fact, someone who actually has the expertise to implement the features of Squirt into a spreadsheet, would not use a spreadsheet to do it. ) This is my opinion but I think it really helps explain why pressure distribution systems generally cost so much more than pump-to-gravity systems. Intelligently designed pressure distribution systems are superior in many ways to gravity systems and the two should be fairly close in cost but this is not what we have seen in the industry. Perhaps if engineers make an effort to improve their tools, their designs will also improve and we will see better systems installed at lower cost.

Squirt Tutorial Videos

2011-09-25T09:10:00.005-06:00

The video below provides a short tutorial covering central manifold configurations. Currently, I have uploaded three videos to youtube examining End Manifold, Pitchfork Manifold and Central Manifold. Youtube search terms, squirt and wastewater will bring the videos up.

Take a look and let me know what you think. I will be producing more of these and if there is a topic you would like to have me cover, send me an email at info@squirtonsite.com

New Squirt Lessons

2011-09-08T19:37:00.000-06:00

I will be posting a set of instructional videos describing Squirt and showing users how to define systems very soon. The first in the series will focus on overall piping layout and configuration with emphasis on lateral and manifold numbering conventions.

Squirt is designed to calculate the most common piping configurations and some that aren't quite as common. Squirt's capabilities are far beyond other simple pump selection calculators and it represents the very first, robust, design tool for calculating pressure distribution system hydraulics.

Remember, Squirt is still free and I urge you to get yourself a copy and take it for a spin. It's on me.

Also, I have recently added quite a few new posts to www.eliminite.blogspot.com

On that blog, and on our Eliminite website, www.eliminite.com you will find information on our biological nutrient reduction system that is quickly setting a new standard in treatment and affordability.

Oh..how could I forget......Squirt is now patented.

State of Florida Requirements For Pressurized Systems

2011-08-24T10:27:00.002-06:00

I have been working with an engineer in Florida and have learned about a unique(quirky) requirement that state has imposed on pressurized systems.

Florida's design standards require that a velocity of 2 ft/sec must be demonstrated at the laterals connection with the manifold. Exactly why they have this requirement escapes me. I also wonder why 2 ft/sec, why not 3 ft/sec or 2.367821 ft/sec?

Obviously this is an arbitrary number based on some unsubstantiated rule of thumb that, if you examine it, starts to look pretty silly.

I suspect the value of 2 ft/sec has something to do with scouring velocity. This is usually applied to gravity sewers in an attempt to keep debris moving along the sewer line toward the treatment plant. I won't argue the validity of the value 2 ft/sec. I will simply assume that whomever arrived at that number had a good reason for selecting it.

Let's assume that the requirement is valid and it is important to maintain a scouring velocity in the piping system. The graph below shows the in-line velocity as function of orifice number. The red line represents 2 ft/sec and the blue line is the velocity.

The Florida requirement is met at Orifice 15 where the blue line and red line meet but after the 15th orifice the velocity drops below 2 ft/sec. If it is important to maintain a minimum velocity anywhere, isn't it important to maintain it everywhere?

I do not have much experience with this requirement and would have to run quite a few simulations to get a feel for how the entire system responds to this requirement. Since I understand the FL regulators are using tables to review these systems, I would guess they have many that are not distributing the effluent uniformly.

This example illustrates how imposing arbitrary regulations without a thorough evaluation can lead to problems. In fact, it would be far superior to specify a distribution uniformity (say, Max 10% flow deviation) across the system, install a flushing assembly and ignore the velocity. This makes sense because the 2 ft/sec requirement is not met for the majority of the lateral anyway.

Orifices: Soil Types, Residual Pressure and Size

2011-08-16T15:57:00.000-06:00

I have had a few questions recently regarding lateral orifices.

Question: Are soil type and orifice spacing related?

Answer: Generally speaking, yes. Orifice spacing is related to soil type in that, wastewater is best applied to coarse soils through more closely spaced orifices. Finer, less permeable soils, will accommodate orifices having a greater spacing. This works well because the distribution system will be smaller in coarse soils than in tight soil so achieving uniformity with the more closely spaced orifices is balanced by the smaller piping network.

I generally utilize orifice spacings of 2 ft. to 5 ft.

Question: What residual pressure do you recommend?

Answer: This one is all over the place. I design with residual pressure of 7 ft. to 12 ft. Higher pressure helps keep orifices clear and results in a higher flow velocity through the lateral, which, helps keep orifices clear. I use Squirt's automatic pump selection feature to select pumps meeting my residual pressure requirement while operating close to their Best Efficiency Point(BEP)

Question: What orifice diameter do you recommend?

Answer: There has to be a good reason to use an orifice smaller than 3/16 inch diameter, unless you really like to clean orifices. My long term testing has shown good results with 3/16 inch orifices. Don't be tricked by fancy marketing material disguised to look like technical journals telling you 1/8" orifices are fine to use. This is usually a trick to get you to buy their overpriced pumps and not a sincere effort to help you with your design.

I need your input

2011-07-23T17:18:00.000-06:00

Now that the Patent Office has issued a patent for Squirt it is time to finish the next version. I have quite a few upgrades planned including ....I took that sentence out before I published the blog because if I tell you what I am working on here, on the web, I will just be creating competition and unnecessary work for myself. If you would like to know where Squirt is headed, just ask.

Please let me know if you have any specific requests and I will see if I can incorporate them.

Thank You

I want to extend a warm thank you to everyone who has been using Squirt. I appreciate your questions and really enjoy working with everyone who has contacted me. Thanks also for your patience as I put things back together from the website hacking attempt.
Tom

I keep trying to help designers avoid blunders like this......

2011-07-16T15:00:00.001-06:00

Picture it: A big sand mound system with hundreds of laterals. Piping arranged in 5 "zones". Two, 5 hp grinder pumps to pressurize the mound. One tiny little automatic distributing valve feeding the pipe network. A broken flowmeter and a 90% compaction specification on the sand.

As you can guess the system has been fraught with problems. The engineering group installed the cleanouts, hundreds of them, sticking out of the ground. Easy access I guess. Well, when the snow fell, the cleanouts were covered.....until the snowmobiles drove over the surface and started breaking them off. This resulted in the grinder pumps (For the life of me I cannot figure out why anyone would dose a sand mound with grinder pumps) discharging to the surface of the mound until summer when the snow melted, what a mess. The problem was somewhat abated because, as they do, the automatic distributing valve was stuck in one position and was only allowing a single zone to be dosed. (As an aside, if you use an automatic distributing valve, use a FIMCO brand valve. www.fimcomfg.com It is far superior to the other brand because it has, among other very useful features, an indicator that displays which zone is currently being dosed. This feature allows the O&M provider to check the valve to make sure it is working properly.)

They fixed the cleanouts by pouring hundreds of little concrete donuts around the PVC sticking out of the ground and inserting an 18" piece of steel re-bar. This is really smart because now the potential exists for the snowmobile rider to hit the re-bar, be thrown off the snowmobile and be eviscerated on the next piece of re-bar.

The design is so full of mistakes, compaction of the basal area to 85% standard Proctor for instance (I'm serious!), that I cannot list them all here. The hydraulic analysis is also severely flawed.

They used a toy program to analyze the drainfield hydraulics and are totally unaware of the fact that the orifice flow difference is approximately 100 times greater than their program reports. I tried to discuss this with them and they looked at me like I was from outer space.

The drainfield is configured as a central, pitchfork design and requires a fairly sophisticated algorithm to accurately analyze it. Squirt handles it easily.

The lesson is, if you use a toy to conduct an important analysis and put your stamp on the screwy results, someone may find out and call you on it. I am not trying to slam these guys but the work is so poorly done and they refused to even consider what I was saying in private that I thought it would make a good blog post that others could learn from.

Please take the time to understand how these programs work and what their real purpose is. Squirt is designed to calculate drainfield hydraulics, it is not a marketing tool developed to sell you pumps.

I will put up a drawing of the system because it is instructive. Right now I am on the road in Colorado working with engineers, installers and builders. You can see some of what we are doing in Colorado at www.eliminite.blogspot.com

The Patent for Squirt is No Longer Pending.

2011-06-25T20:21:00.001-06:00

Squirt is now PATENTED by the United States Patent and Trademark Office!

It is this easy...

Step 1: Define your system.

Step 2: View your results.

Step 3: Plot your pump and system curve.

Step 4: Print your results.

More about the Highway Rest Area system

2011-03-02T09:49:00.002-07:00

Eliminite has been selected as provider of all wastewater treatment facilities for Montana Department of Transportation (MDT) highway rest areas and other facilities. Through its process, in conjunction with the Federal Highway Administration, MDT determined that it is in the best interest of the public for Eliminite to provide wastewater treatment systems for all its facilities. The systems are compact, reliable and specifically designed to treat the high nitrogen wastewater (ammonia = 180 - 250 mg/L) common to highway rest areas.
The foot print of the entire treatment system is about 20' x 40' and uses all locallly supplied precast concrete tanks. That makes good sense for our local economy because area suppliers can provide equipment rather than shipping money out of state to import equipment from out of state, or country, suppliers.

We can do this in any location using locally available tanks, and components because the design of the system is flexible and can be modified to accommodate almost any tank configuration. This not only provides a boost to the local guys but also results in significantly lower overall cost. As you all know, "pod" type systems must be shipped in from somewhere.

This system was started and sampled in the dead of winter and is already achieving about 98 % conversion of ammonia to nitrate. No alarms, no malfunctions, no phone dialer. The average mean temp was around 20 degrees F for the operational period.

A photo if the rest area is at http://www.eliminite.blogspot.com/

For viewing results quickly....

2011-03-02T09:16:00.000-07:00

Squirt has a "quick results" window. In this example, it would be a good idea to consider increasing the diameter of the pump discharge piping.

Lets get back to business.

2011-02-23T15:19:00.003-07:00

If you are a current Squirt user and your License Key has expired, email me the Registration ID and I will send you a new key. If you are new to Squirt, I have significantly modified the download procedure and security procedures. You will need to contact me for instructions. I realize that the new download procedure is a bit of a pain, but it is necessary to keep certain companies (nudge, nudge, wink, wink) from abusing the privilege. So just send me an email to info@squirtonsite.com and I will take care of you.

The photo shows a a good friend of mine, Contractor Frank Rask, checking the pressure distribution on a fairly complicated drainfield for a highway rest area I designed using Squirt recently. It has two, 3000 ft, forcemains and about 2000 linear ft of distribution line. The laterals are on a sloping site. Frank built the system and we tested it. (He did a damn fine job. Frank works for Dick Anderson Construction of Helena, Montana. If you need a competent contractor to install a system, erect a building, build a road etc. I suggest you give them a call) .

The drainfield is so big I could not capture the entire thing in a single frame with the camera in my Droid. But you can still see that the distribution is perfect. No automatic distributing valves, solenoids or other unreliable gadgets were used, just sound hydraulic design and engineering. We did not use ball valves to adjust the pressure differences caused by the sloping site but rather, designed the system to function with the slope. The tricky part was calculating the differential pressure caused by the main filling and draining. Flow variation is less than 10% across the entire field under all conditions. A photo of the facility being served is on my other blog http://www.eliminite.blogspot.com/

Back in the Saddle

2011-02-08T18:01:00.002-07:00

I fixed the problems and it looks like we are going to be back online.

Existing users can email me for a new license key.

Trolling offshore with Amanda at the helm

New users will need to get a password from me to access an FTP site and, after downloading the zip file, will also need a license key from me. These are still free but I need to weed out the little monkeys that caused me so much trouble in the past. I will set up the download site tomorrow. Actually, my good friend Mark is setting it up for me. Mark is a SCUBA instructor in Ft. Lauderdale Florida and has a degree in Computer Science. Check out his site at http://www.seaxp.com/ Amanda and I took lessons from Mark and had a great time. We dove on wrecks in Florida and a reef in Key Largo. Mark took us for a night dive off Ft. Lauderdale and I have to admit I was pretty scared at first...I mean I wasn't looking forward to meeting a 14' Tiger shark in the dark in the north Atlantic Ocean. Amanda, on the other hand was looking forward to the dive and couldn't understand why I was so nervous. I guess they make the women pretty rugged in Wisconsin...go figure. We had a great time and if there were Tiger sharks in the area, they let us dive in peace.

We are almost back online!!

2010-12-29T11:27:00.001-07:00

Dear Big Guys:
I have finally fixed the little problem with the Squirt download. I want you corporate guys (you know who you are) to stay the hell off my site. I have been providing Squirt free of charge and if you would like a copy you will have to swallow your pride and ask. Yes, Squirt is FAR Superior to that silly little tinker-toy you produced but come on....hacking into my software? Have a little professional dignity. That said, if I catch you on the site again, I am going to post the data from my web analytics software right here for everyone to see. I am serious about this.
hugs and kisses
Tom

To everyone else:
I apologize for the rant. I think Squirt is the BEST tool for design and analysis of pressurized drainfield hydraulics and NOTHING ELSE even comes close. Please be patient while I get the download back up.
Tom

I had to deactivate the Squirt website

2010-10-15T11:52:00.000-06:00

Apparently, a certain party was downloading quite a few copies of Squirt without entering correct (honest) information. They were also not requesting license keys from me. This is odd because I have been providing Squirt for free.

The truth is I know who was doing it because they left a trail of digital breadcrumbs that was pretty easy to follow. I was not surprised because they have copied my work before.

If you would like to request a copy, just send me an email to info@squirtonsite.com and I will send you a copy.

So you want to learn how to design a pressure dosed drainfield?

2010-05-08T13:42:00.000-06:00

So did I. I read everything on the subject I could get my hands on related to pipe hydraulics, pumps and pressurized drainfield systems. I took soil science classes to help develop and understanding of the interaction between soil and water. My degree is in Chemical Engineering and I have a minor in Mathematics, I figured I should be well prepared to tackle the practical and theoretical aspects of fluid flow in pressurized drainfields.

I remember my first pressure dosed drainfield design and the elation I felt seeing it squirt "correctly". If you have designed and built them you know what I am talking about. I also remember one (and there has only been one) that almost did not meet the minimum squirt height of 2.3 ft. We were using a siphon (I refuse to use siphons anymore) and because the building sewer exited the home deeper than shown on the architects plans, the septic/dose tank had to be installed deeper. This unaccounted loss of elevation pushed the system right to the edge of regulatory compliance. The system passed but it kept me up at night because I try very hard to get things right and it irritated me that I had designed a system that had little margin for error.

Through the years my engineering firm designed hundreds of pressurized drainfields. I had the good fortune of working with some of the brightest engineers in this field anywhere. Several of them really stand out in my mind and I still hold them as the "Gold Standard" against which all others are judged. These engineers had a burning desire to know and were never content with guesses. But they were damn good guessers too, hell they could guess things other engineers at competing firms couldn't even calculate! I really learned a lot from them and it was our spirit of solving problems that drove me to write Squirt.

We had to design a particularly challenging pressure dosed drainfield for a job. It was on a hillside on an irregularly shaped piece of property. We needed every square inch of available land and had all kinds of constraints from steep slope setbacks, wetlands, a creek, trees, rock outcroppings, roads and visual impact concerns. It was also a pretty big drainfield with more than 2000 ft of lateral per side. Our brightest engineer, Cordell, had the responsibility of designing the spreadsheet analysis for this drainfield. Now, I don't want to insult any of you reading this but chances are Cordell is a lot smarter than you....he is certainly smarter than I am. And to those of you who proudly proclaim that you have a spreadsheet to claculate and analyze your pressure dosed drainfield designs, I am fairly confident when I say you don't have anything even remotely close to what Cordell put together to design this nightmare drainfield. It was a remarkable effort and the drainfield squirted exactly as designed. It had to. It wasn't one of those you hear about where the squirt is uneven so the engineer calls the pump supplier and has him bring out every pump in stock in a futile attempt to get the damn thing to work. This drainfield was fed with $15,000 pump package and we had one chance to get it right. Which we did. It has been in operation for about 12 years and the soil surface still looks beautiful. No ponding, no clogging and the original pumps are still operational. In short, a nearly perfect blending of pipe hydraulics, soil science and onsite wastewater treatment.

I used Cordell's spreadsheet as one model for Squirt's code development. I would check Squirt's results against the spreadsheet and look for consistency between the two. It has been interesting to obtain the same and, more refined, results in a fraction of the time it took to develop the spreadsheet. Also, like most spreadsheet models, this one was a one time deal. Changes to the piping layout would require a redesign of the spreadsheet and dozens of man-hours to check and re-check the results. With Squirt, you can get results as fast as you can enter data. It has been a great time saver.

Having had these types of experiences over the years has allowed me to develop an intimate understanding of these systems operate. I have to laugh to myself when I hear from the well known college professor at the university in North Carolina who tells me that a sanitarian he knows has developed her own spreadsheet that does what Squirt does. Or from the young engineer that does not trust anyones "black boxes" and has his own spreadsheet that works exactly the same way Squirt works (I have a copy of his spreadsheet, it doesn't). The most amusing however are the designers/engineers that vigorously defend the couple of drainfield programs out there being used today without really knowing anything about how the program works or the fact that is does not.

Adding Pumps to the Pump File by Clicking on the Pump Curve

2010-04-28T19:13:00.000-06:00

I get a lot of questions on this topic because Squirt's "Add Pump" feature is so useful. All you need to do to add pumps is copy a pump curve to the Windows Clipboard and Click "Load Curve" in squirt. In this example I selected a Myers ME 100. Squirt asks you to click on three points on the grid to define the limits then simply click five points on the pump curve from left to right. Thats it! When you click "Save Pump" Squirt will ask for details such as pump manufacturer and model, horsepower, etc. The pump is saved into the pump file and available for analysis in all your designs.

This is a great time (and eyesight) saver and you will not find this feature on any software except patent pending Squirt.

Designing sloping pressurized drainfields

2010-04-11T09:17:00.000-06:00

If you need to design a pressurized drainfield on a sloping site, Squirt makes it easy. Just enter the lateral elevations and Squirt will automatically calculate orifice plate sizes necessary to acheive uniform distribution. This method is preferred over the old-fashioned way of varying orifice spacing along a lateral to account for pressure differences resulting from elevation differences. Remember, lateral orifice spacing is selected by soil type not hydraulic requirements. Squirt supports correct lateral orifice spacing by controlling lateral pressures at the manifold. Some engineers still call for ball valves to be installed at each lateral to control pressure on sloping sites. In my opinion this is poor practice and should be prohibited by regulatoy agencies. I have seen quite a few engineers wind up looking like this

while trying to adjust ball valves to get the pressure correct. What must the clients think when they see their professionals engaging in such random activity.

If you send me an email I will show you a really cool way to control pressure on sloping sites.

If it's worth doing isn't it worth doing right? Why GUESS when you can KNOW?

2010-03-11T13:04:00.003-07:00

If you are designing a pressurized drainfield system why would you use a tool you know gives the wrong results?? This has special significance for you engineers out there because when I tell you that the pump selection program (cleverly masked to make you think it is a pressurized drainfield design program) you are using, and billing your clients for, gives wrong results, you now have knowledge of this fact and are therefore in violation of your ethical obligations to the client andthe Profession. I urge you to give Squirt a try. I am sure you will like the fact that this powerful design tool quickly provides hydraulic calculations for every lateral and pipe in the system. It also allows you copy and paste pump data from the web and build your own pump file rather than being hobbled by one manufacturers line of pumps. And I don't want to hear about spreadsheets either.....anyone with the expertise to write a spreadsheet to do what Squirt can do, wouldn't use a spreadsheet to do it!
Go to squirtonsite.com and download a free copy today before I start charging for it!

Department of Homeland Security Port of Entry Scobey, Montana

2010-02-05T15:01:00.055-07:00

About $13,000,000. This is the price tag of a new, shovel-ready, American Recovery and Reinvestmant Act project in Scobey Montana. Yeah..I live in Montana and had to find Scobey on a map too. So do, apparently, the people who need to use this US port of entry to enter the country. In fact it is so remote that only about 25 people pass through its gates each day. Yet, our government is spending around $13,000,000 to upgrade this diminuitive port. Now since the taxpayers are going to be on the hook for that kind of money you would think that at least the engineering being done would be top-notch, pearly-gates type of work. Here is a fun little link: http://www.cnn.com/2009/US/09/17/border.security/index.html

(As an aside, I bet the people of Scobey think this whole fiasco is ridiculous too. In fact, the money would have been better spent by just GIVING it to the them and letting them protect the border! Then we wouldn't have to worry about any undesirables getting across the entire northern border because I hear they are pretty rugged people up there!)

So, as the friendly government purchasing agent, you know, the guy who goes through money faster than an industrial paper shredder, what do you do? You hire BIG, IMPORTANT engineering companies to get the job done right...the first time. And if you have to pay a little more for it....well that's the price of Recovery.

What I would like to illustrate is that after, or in anticipation of, paying $13,000,000 for an unnecessary extravagance located east of East Jesus, Montana, we still do not even have the benefit of saying, "Well, yeah..that thing was damn expensive but at least the pressurized drainfield meets State requirements!" No in fact, I was fortunate (?) enough to have a friend send me a set of engineering plans from the Port of Scobey wing-ding and I, being the inquisitive person I am, decided to analyze the pressurized drainfield design through Squirt. Here are the important input parameters so you can give it a try:
Orifice Diameter: 5/32"
Orifice Spacing: 5'
Lateral Diameter 1.5"
Lateral Length: 100'
Number of Laterals: 6
End Manifold Configuration
Lateral Spacing: 7'
Manifold Diameter: 2"
Forcemain Diameter: 2"
Forcemain Length: About 150'
Elevation: about 5' from pumping elevation to discharge.

The engineer used a well known pump-selection program. The one that suggests it cares about your designs when all it really wants you to do is but it's pumps...It gives a percent difference in flow of 4.5% using the parameters I have listed above. In Montana, the regulations require no more than a 10% difference in flow across a pressure dosed drainfield. So...this design is A-OK and should be approved, right? Wrong.

Because the Engineer refuses to think about what he is doing, the taxpayers are spending an enormous sum of money for something that does not even meet state requirements. When you analyze the drainfield parameters with Squirt you can see that the actual percent difference is almost 30%! What happened???

What happened is the author of the pump selection program was so focused on duping you into buying his pumps that he forgot to write the code that actually calculates the drainfield hydraulics! If you are designing pressurized drainfields you should be able to check these results for yourself. If you don't know how, contact me and I will help out.

My point is that even when we through an almost unimaginable amount of money at a miserably dimuitive project, the engineers STILL cannot obtain the correct results. It's a good thing these guys don't design airplanes or heart valves because we would all be in trouble.

I would really like to be able to put up a link to their Quality Control statement. The one where they tell prospective clients that quality is more than just a word...it's a culture. Almost a religion of quality. Just as long as it doesn't require any math.

Check back today for an interesting comparison

2010-02-05T12:57:00.000-07:00

I am going to compare results for a pressure dosed drainfield design obtained from Squirt and another pump selection program. I will give input parameters so you can see just how far off the other program is.

Switching to Eliminite in Montana

2010-01-26T13:26:00.001-07:00

Many of our Montana customers had property that was previously approved with a competing wastewater treatment system but decided that it was in their best interest to switch the system shown on their plans to Eliminite. Quite a few of these owners were told by the distributors of the competing systems that they had no other option and were required to install the system as shown on the plans. This is not true. In fact, the process is really quite simple. In many Montana Counties all that is required is that the swap be noted on the "As-Built" drawings. In other words, no advance permitting is required at all and the owner is free to select Eliminite in place of the other units. I will be posting a list of counties where this rule applies. In the other counties, MDEQ has implemented a simple procedure for completing the swap. I have done this for many clients and it only involves a short application, lot layout sketch, and administrative fee of about $200.00. The process takes 10 days or less. MDEQ decided to streamline the process for making the switch because so many people want to install a different wastewater treatment unit than the one their engineers decided to show on the plans. So what does this mean to you?

Everyone is looking to save some money these days and Eliminite will provide relief from other high priced Level 2 systems. You benefit from our local manufacture and use of local materials. If you are planning to install a system we can almost always save you money. In fact, even on single family residential applications, Eliminite can save you several thousand dollars over our competition. We also give you the option of selecting your own installation contractor and O&M provider. This means you will not be held hostage by a manufacturer to use their installer and pay their maintenance prices.

If you are an engineer, your clients will appreciate your effort to save them money and provide their clients with more choice. Plus, the people who buy lots in the communities you are designing will like the smaller, less obtrusive footprint of Eliminite as well as our less invasive maintenance procedures.

I also must tell you that this procedure works both ways; you may also swap an Eliminite for a competing system in the same manner I discussed above. Honestly, this almost never happens because when people compare advanced treatment systems they will almost always choose to go with Eliminite because we offer the end user so many more advantages, features and significantly lower cost.

The paper NOWRA doesn't want you to see.

2010-01-18T13:30:00.000-07:00

I wrote a paper for the NOWRA conference that apparently really upset the review committee and, after receiving quite a few snippy comments, I decided to pull it from the conference proceedings. The purpose of the paper was to compare Squirt's results to those presented in several "accepted" design papers. Essentially, I simply ran the numbers in the "accepted" design paper through Squirt and examined the results. In another example, I built the pressure network at my test facility and measured the residual pressure in each lateral with a manometer and compared the measures pressures to those presented in the textbook. The results were surprising, exciting and in some instances, counter-intuitive. But apparently, NOWRA is not in the business of questioning how things work or searching for better ways to serve the public. Rather, one reviewer seemed fixated on his notion that I was lying about Squirt's patent pending status. (Squirt is Patent Pending) It struck me as odd that the review committee (except for one person) seemed to be personally invested in pressure distribution system design and felt threatened that a new, better, more powerful method had been and was being developed. If you like I can discuss the results of the study with you. Here is one conclusion from the paper:

It is clear from the results that, due to the large diameter manifold, lateral flow rates agree with the Stump Creek calculations presented by XXX through Lateral 8. Beyond Lateral 8 however, minor losses and friction loss in the manifold causes the flow rates to begin to deviate significantly. In the Residual Pressure column at the right side of Table 3, one can inspect the calculated residual pressure at the distal orifice of each lateral. Recall that the initial specification for residual pressure at the distal orifice was 2.5 ft. It can be seen that this specification holds through the eighth lateral, however as pressure losses due to friction increase along the manifold, the residual pressure shoots up to 4.5 ft at the laterals closest to the force main. The non-uniformity of flow rate across the system is therefore approximately 42% in spite of the fact that individual laterals only display a 6% variation. In the field this system will show a 2 ft. difference in squirt height from the first to the last lateral. Furthermore, as the manifold pressure increases, so does the lateral flow rate going from 29.4 gal/min to 39.4 gal/min, an increase of 10 gal/min. This means that during a dosing cycle which may last for approximately 4 minutes, two times per day, lateral 20 will receive approximately 80 gallons more effluent than Lateral 1 each day.

It is all about money

2009-12-10T13:42:00.001-07:00

I like an assortment of pumps and I cannot imagine a drainfield design program that forces the user to have only one brand of pump included in the pump files. It kind of tells a story doesn't it? What do you think the markup on a pump is? 40% ? 50%?. So it kind of makes sense to slap together a free pressure dosed drainfield program, without rergard for how well it actually works, so that you can SELL MORE PUMPS. What confuses me is that there are still some "engineers" who refuse to question what they are using to design systems for their clients. That's a big problem with this field and a reason why decentralized is not looked upon as a serious alternative but rather a temporary patch until a "big-pipe" is available. System designers that follow blindly and are willing to commit intellectual suicide for the sake of a manufacturer. It reminds me of the Helsinki Syndrome for onsites.

LPD Pressure Distribution Pressure Dosing Uniform Distribution

2009-09-23T07:11:00.003-06:00

Whatever you call it, Squirt can do it. I thought it would be a good idea to provide a quick rundown of some of the things Squirt can do and its features.

Squirt gives REAL results by calculating every lateral as part of the system.

Squirt ACTUALLY CALCULATES end manifold, central manifold, pitchfork manifold and central pitchfork manifold configurations.

Squirt allows the designer to vary lateral spacing by varying the length of manifold segments.

Squirt allows laterals to be designed from two different diameter pipes...this helps manage dose volume, scouring velocity and friction losses.

Squirt allows the designer to copy and paste pump curves from the web, scanner, jpeg, bitmap etc ans simply click points on the curve to add pumps permanently to the pump catalog.

Squirt gives the designer the ability to identify the most efficient operating point on the pump curve.

Squirt has an AUTOMATIC PUMP SELECTION feature. One Click and Squirt will find every pump in the catalog that matches the system according to the designers specs.

Pump curves are plotted with the system curve and the REAL operating point (head and flow) is presented as well as the residual pressure at the operating point.

Squirt easily handles a sloping site where laterals will be installed at different elevations.

Squirt is a stand-alone program that is robust and customizable.

If you are still using elementary pump selection programs or cumbersome, incomplete spreadsheets you should know that Squirt is those as a computer is to an abacus.

Add Pumps to Squirt

2009-08-14T21:13:00.004-06:00

Squirt has a unique feature that allows the user to build their pump file as they need to. You can enter the data manually or copy a pump curve from the web or scan one in. Just click on several point and the curve is loaded and saved for future use. Once a part of the pump file, it is available to Squirt's unique Automatic Pump Selection feature. You set the search criteria, click, and Squirt finds all the pumps in your pump file that match the criteria. Squirt will backsolve for TDH, flow rate and residual pressure at eh operating point of your pressure distribution system.

Failed Sand Filter

2009-08-09T16:19:00.004-06:00

On my other blog, http://www.eliminite.blogspot.com/, I generously discuss my thoughts about a recent job we completed where we were abandoning a wonderfully failed sand filter. I decided to take a look at the pressure distribution system in Squirt and see if I could figure out why the owners had to also spring for a new pump. After entering the pipe data into Squirt and calculating a system-pump curve I think I know why. The system curve and pump curve do not intersect in the operating range of the pump. So every time the pump turned on, it was just free-wheeling. Kind of like putting your car transmission in neutral and holding the gas pedal all the way down. Therefore, because the engineer did not do a competent job of selecting a pump that fit the job, the owners get to pay.

By the way...I examined this system with one of those goofy little pump selection toy programs and it says everything is fine. I'm not pulling punches here, I am going to tell it like it is and I don't care if people get their panties in a wad. If you are using the toy programs or the home-made spreadsheets, you are getting incorrect results, period.

Amazing Bozeman Sunset

2009-07-27T12:22:00.003-06:00

I needed a break from all the pressure dosed drainfield talk.

Pump chamber design

2009-07-10T14:06:00.004-06:00

Squirt has a nice routine for designing pump chambers and the associated piping. It makes full use of Squirt's Automatic Pump Selection features. Take a look at the updated pump chamber screen at http://www.squirtonsite.com/.

Pressure Dosed Drainfield Design Example cont.

2009-07-05T17:20:00.014-06:00

Because the laterals are installed on a slope, Squirt has calculated the orifice plate orifice diameter that will control the flow to each lateral. This plate is installed between the lateral and manifold in a union or other fitting ( I'll give you a good idea on how to do this if you ask). With this set up, the entire system calculates out to a 3.28% difference in flow. This is very uniform and satisfies the requirements. The next thing to do is select a pump. In the pump selection screen I have set the tolerance at plus or minus 10 gpm from the best efficiency point of the pump. In other words, I only want to see pumps in my pump file that when connected to this system will operate within 10 gpm of their most efficient operating point. Below is the screen where I set this requirement. I could have used the default tolerance but I wanted to focus in a a pump that gives me a good residual pressure and operates efficiently. Inefficient operation is a main cause of premature pump failure and if the pump is not sized to the system correctly it will not last. (There is no commercially available pressurized drainfield software that generates a true system curve for comparison with a pump curve. ) The next thing to do is click on "Automatic Pump Selection" button and see which pumps fit the criteria. The result is shown below. Squirt has parsed the pump file and located pumps that meet the criteria I set and displayed them with the system curve. In the window at the top of the screen, the pump model, residual pressure, flow rate and TDH is displayed for each pump. ( Now I know that this is a design example and I should probably stick to the subject but let me just say to the university professor "expert", you do not have a spreadsheet that does this! Furthermore you only illustrate more clearly your total lack of understanding of this subject if you think you do. Thanks...I needed that.) Back to the example. I like the Hydromatic SPD 50 because it is a good pump and it will operate very close to its BEP and produce a squirt height of 8.1 ft. I don't agree with using 5 ft of residual pressure as a design value. I prefer more pressure on the orifices to help keep them clean and increase the time interval between flushing.

The last thing to do is update the orifice plates by taking the 8.1 ft of residual pressure the pump produces and enter it back into the main screen where it says "Residual Pressure" and recalculate the table with orifice plate diameters. The new orifice plate orifice diameters are shown on the screen. The diameters are close because the elevation difference between the laterals is small and because we are using a large diameter manifold. I could have used a 1.5" diameter manifold and produced acceptable results. So there it is. This example does not even begin to illustrate all Squirts functionality. If you design pressure dosed systems you really need to take a look at Squirt. I am pretty sure you will not want to go back to whatever you are currently using.

Pressure Dosed Drainfield Design Example cont.

2009-07-03T10:53:00.000-06:00

I clicked on the results button and Squirt presents a results table that shows the calculations for each lateral. Notice the percent difference calculations are shown for each lateral and the entire system. Also shown is the total dynamic head and total flow rate, dose volume based on pipe volume and velocity and head loss results for the discharge piping and forcemain.

Notice the head loss in the pump discharge piping of 15.40 ft. That seems a little high to me so I am going to try 2" discharge line instead of the 1.5" and see what happens.

The head loss through the discharge pipe has been reduced and the TDH went from 39.5 ft to 28.57ft. I like this better

Pressure Dosed Drainfield Design Example cont.

2009-07-02T19:30:00.000-06:00

This is the data I am going to analyze:
Lateral length: 64'
Lateral diameter: 1.5"
Lateral spacing: 8'
Orifice spacing: 5'
Orifice diameter: 3/16"
Manifold diameter: 2"
Forcemain diameter: 2"
Forcemain length: 42'

Additional data such as the pump discharge pipe characteristics, pipe fittings, elevations etc. will just be entered directly into the program. The input window is shown below. Click on the screen shot to enlarge it.

Pressure Dosed Drainfield Design Example

2009-07-02T08:32:00.000-06:00

I have a pressure dosed drainfield to design so I thought it would be helpful to present the steps I follow using Squirt. A portion of the site plan is shown on the right. I have already assessed soil conditions and site characteristics and have decided to use four, 64 ft long laterals. As you can see the system will be installed on a slope. Because soil type does not change across the drainfield area, lateral orifice spacing will be constant. I want to take advantage of the A Horizon so each lateral will be installed at a depth of 18". The drainfield will be supplied with one pump, pumping to one forcemain. I don't particularly like automatic distributing valves because I think they add an unnecessary level of complexity to the system. It is easy to design a system without them and that system will be easier to build and maintain. Just as an aside.....it seems like the people in this industry yelling the loudest for perpetual maintenance for onsite systems are peddling or designing the most unreliable junk imaginable. I guess the two travel together. I can start entering data into Squirt now.

System Head-Discharge Curves

2009-07-01T09:34:00.000-06:00

In a pressure dosed drainfield the (actually in any pump system) the TDH in the system must equal the head developed by the pump and the discharge in the two must be equal also. (Sanks 1989) This point is called the operating point and, graphically, is the intersection of the system head-discharge curve and the pump characteristic curve. Squirt automatically generates a system curve and pump curve and solves for the operating point. Squirt will also then solve for the residual pressure (squirt height) at the operating point. The screen shot shows the system curve (in black) and the pump curve (in red). Squirt has calculated the operating point and residual pressure in the drainfield. If you want to look at more than one pump, Squirt will plot as many as you like on the same graph and solve for the operating point and residual pressure of each.

Percent difference in flow

2009-06-29T10:35:00.000-06:00

Squirt calculates percent difference values for each lateral in the system as well as a single value for the entire system. Spreadsheets and other elementary programs only provide a percent difference value for a single lateral. Clearly, a single value is incomplete and may significantly understate the actual non-uniformity of the system. For instance, some well regarded references outlining design methods for pressurized systems calculate only a single lateral in the system. The result shows a minimal percent difference, 1 to 2 percent. But this is the difference along just one lateral and in a system with more than one lateral the error can be huge. Entering the the system data into Squirt and solving the system will show differences across each lateral, and the residual pressure at each lateral end. The percent difference across the entire drainfield is displayed for a true and complete analysis. In the example above the actual calculation produced an 86% difference, not 2%.

Clean, intuitive user interface

2009-06-27T09:49:00.000-06:00

Squirt has a clean, simple user interface. This screen shows input data for a 12 lateral system

2009-06-26T12:21:00.000-06:00

....I have a spreadsheet that does that.....

I have heard this so many times that I have lost count. In fact a self-proclaimed university expert told me that he teaches advanced classes on pressure distribution system design using a friends spreadsheet and would not even take a look a Squirt. I think that if a person knew enough about spreadsheets to actually write one that can do what Squirt can do they would not use a spreadsheet to do it. Now I don't want to sound abrasive here but if the spreadsheet only calculates one orifice or one lateral, and the system being designed has more than one orifice or more than one lateral than the calculation is incomplete and probably incorrect. Period. Sorry for being so blunt but that's the way physical reality works. Squirt calculates every lateral in the model as part of the system and provides results for the entire pipe network. The great thing about this method is the freedom the designer has to design systems that fit the site more perfectly because the constraints of constant lateral length, constant manifold length and diameter, to name just a few, no longer exist. Furthermore, you can add your own pumps to the pump file by clicking on the pump curve with the mouse. Squirt will automatically select pumps from your pump file that match the system you are designing. Good luck doing this with a spreadsheet. If you need to change orifice spacing or add a lateral, Squirt will do it with a few clicks. Spread sheets usually need to be rewritten or you can try opening up and old job that kind of matches the current job and make the changes. But is all that monkeying around really efficient?

Give Squirt a try.

I used spreadsheets too and I have designed some pretty complicated pressurized systems. That is why I wrote Squirt. I know you will like it.

2009-06-15T07:32:00.000-06:00

This is a simple four lateral, end manifold, system on a sloping site. Squirt calculates the residual pressure at the end of each lateral and presents a list of pumps that will operate closest to their best efficiency points with one click.