Article: How In-Pipe Technology Works

April 3, 2006

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I am always being asked to explain how In-Pipe Technology (IPT) works because the descriptions in my two patents are complex and not easily translated to layman terms. This explanation will also benefit those technical persons whose education, training, and experience do not encompass the several different fields needed to understand all the issues and latest technology breakthroughs. So, I shall attempt to write a simplified description that should be readily understood by most people who have a basic understanding of science, mathematics, and microbiology and that will also benefit persons with a technical background. 


Wastewater (sewage) treatment involves the use of bacteria to process the contaminants in the wastewater. These get into the wastewater mainly from our fecal material. Fecal material and toilet paper comprise the majority of the contaminants in domestic wastewater, with some contribution from food via the kitchen and chemicals from the kitchen, laundry, and bath. Fecal material is comprised of large quantities of bacteria (some estimates of 50% by weight have been made) and is the greatest source of bacteria in domestic wastewater. The soil washed from food, clothing, and skin also provides a small bacterial contribution; however, the presence of chemicals (cleaners, detergents, and the like) and high water temperatures greatly reduce the amount of live or viable bacteria.


Bacteria like to bind themselves together in what is commonly referred to as “slime” but is more technically known as “biofilm.” They do this for many reasons and accomplish this binding by producing what is known as “exocellular polysaccharide substances” or EPS. EPS is composed of high molecular weight, long-chain molecules (up to 100,000 times larger than Helium). The scientific community is just now beginning to understand the mechanisms involved in EPS production. The production of EPS seems to only occur when the bacteria are attached to a surface. Bacteria that are not attached are called “planktonic” or “free-swimming” bacteria. Those that are bound by EPS into a biofilm are referred to as “sessile” or “nonswimming” bacteria. 


Bacteria prefer to attach to a surface rather than swim around. When they do attach and their populations become large enough, they set about producing the EPS to link themselves together. Why they start to produce the EPS in the first place is still somewhat of a mystery. Another unusual aspect is that when they are bound in the EPS, they behave differently than when they are swimming around. Maybe this is best compared to hunter-gatherers tribes of people compared to farmer tribes. They assign different functions when farming compared to hunting in order to survive.


Our human digestive tracts all have bacteria in them. Without the bacteria, we could not exist. It is believed that any given person may have between 40 and 200 different species of bacteria in the digestive tract. Also, it has become known that these bacteria are all bound in EPS within the digestive tract. So, the majority of fecal matter is comprised of “sessile” bacteria. It must be pointed out that sessile bacteria can and do break free of the EPS and become free-swimming, planktonic bacteria; however, these appear to be few in number and not much is known about the process. Because of the small numbers that break free, they have very little impact on the process.


One thing that is well known about the difference between sessile and planktonic bacteria is that they reproduce at markedly different rates. Bacteria are principally single-cell life forms and reproduce through a process known as cell division. That is to say that when the signal to reproduce begins within a bacteria cell, it expands in size and ultimately divides into two cells. One called the “mother” and the other the “daughter.” This division occurs at different time intervals (rates) depending upon a number of conditions, including whether or not they are in a sessile or planktonic state. Planktonic state bacteria multiply at a higher rate than sessile state bacteria. This difference in the rate of multiplication is one of the prime factors in how IPT “works.”


For example, if planktonic bacteria divide at twice the rate of sessile bacteria, there will be more planktonic bacteria present after a given amount of time assuming we start with equal numbers of both. Because each new daughter bacteria can also divide at the same given rate as the mother, we have what is mathematically known as a logarithmic or exponential growth function. Two becomes four, which becomes eight, then sixteen, and so on for as long conditions allow. If planktonic bacteria can divide every twenty minutes and sessile only every hour, for example, it is now easy to see how a smaller number of planktonic bacteria, introduced into a volume of sessile bacteria, could eventually have a greater population than the sessile bacteria, if other factors permit. One of these other factors is the number of sessile bacteria present compared to the planktonic at “time zero” (starting point).


The sewer piping is divided into two types, depending upon how the energy is supplied to move the wastewater along to the treatment plant. Gravity piping, as the name implies, relies upon the force of gravity to move the water. To accomplish this the direction of flow must be “down-hill” at all times, which is usually the case between houses and the piping in the street. Gravity is also used to move the wastewater from groups of houses in common pipes towards the treatment plant. If there is not enough difference in elevation to bring the wastewater the entire distance to the treatment plant, designers place underground holding tanks at certain points along the way to collect the wastewater from the gravity piping. Once enough water is collected, a pump supplies the energy to move it from the tank into another pipe. The combination of tank and pump may be referred to as a pump station or lift station.


The pipe receiving the wastewater from the pump is called a “force main” which implies that water is “forced” into the piping by the pump pressure. The force main may connect to a gravity pipe where gravity takes over again, or another force main, or another pump station, depending upon system design and topography. The collection tanks at these pump stations are never pumped completely empty, so some amount of wastewater is always left in the tank at the end of each pumping cycle. This remainder is called the “heel.” The heel is also important in how IPT works and will be explained later.


The gravity piping, while always moving the wastewater along, usually retains some small amount of wastewater and particles of various sizes that settle out when the flow is slow. This is especially true in areas where the piping may shift over time due to the settling of the soil, creating low spots along the way. The force main piping may be completely full all the time or drain partially or completely once the pumping stops. The flow velocity in the force mains is often fast enough to prevent accumulations of settled material.


Since bacteria will always attach to a surface and, in time, form a biofilm, there is a biofilm layer throughout the entire wastewater system, from the starting points inside the home all the way to the treatment plants. Sessile bacteria from our fecal matter supply almost all the bacteria to the slime-building (biofilm-forming) process as well as the majority of the contaminants that must be removed by those same bacteria at the treatment plant.


The bacteria species in our digestive tracts are varied where some require oxygen to survive and will die without it, others cannot stand oxygen and do not function if oxygen is present while still others can work with or without oxygen. Those that use oxygen only are called strict aerobes, while those that can only work without oxygen are called strict anaerobes (some people substitute the word “obligate” in place of “strict.”). Those that can do both are called “facultative.”


Another important aspect of how IPT works is the fact that anaerobic bacteria multiply slower than aerobic bacteria and, in so doing, produce less “offspring” bacteria for a given amount of food and nutrients (contaminants to us) removed from the wastewater. As you may have guessed by now, IPT uses facultative bacteria in the planktonic state.


Different bacteria species compete for food, nutrients, and a place to call home (attach). It is a principle of nature that those best adapted to the environment will survive at the expense of those less adapted. This means that bacteria capable of reproducing at a higher rate than others under a given set of conditions will ultimately dominate that environment. This domination will be governed by the amount of food and nutrients available to support the size of the population. This principle of nature is often referred to as “competitive exclusion” or survival of the fittest.


Different bacteria species can process different components (contaminants) within the wastewater. No single species can do the entire job. In fact, bacteria like to live together in combinations of species whereby they divide up the work (contaminant removal). This may also be a reason for the production of EPS, to facilitate the efficiency of the species working together by tying them all together in the biofilm. The biofilm also protects the bacteria from the invasion of other species and from harmful substances that may be in the wastewater. This entire process is a survival strategy dependent upon the environmental conditions at their specific location. Bacteria that like to live together are called “symbiotic,” a term that means compatible.


If we pick and choose select facultative bacteria strains that like to live and work together (symbiotic) under a variety of environmental conditions, we have “select, symbiotic, facultative bacteria” which is exactly what IPT uses. Now, we have established that IPT concentrate is composed of a mixture of planktonic state bacteria that like to live together and can perform with or without oxygen. Being planktonic, they multiply faster than the sessile bacteria in the fecal material.


The bacteria found in fecal material are composed of many different species, some of them are “good guys” which do their jobs without producing odorous, noxious, or corrosive byproducts. Then there are “bad guys” such as sulfate-reducing bacteria that produce hydrogen sulfide, a corrosive gas that smells like rotten eggs. Because there are facultative “good guys” already in the feces, IPT selects many of these same bacteria for the IPT concentrate. The added IPT bacteria act like reinforcements to those already there and work together to become the dominant species through the process of competitive exclusion.


To make this competitive exclusion happen we must start with enough of the “good guys.” Remember that each toilet flush brings more sessile bacteria in the form of feces and that there is an existing biofilm to overcome. The IPT proprietary manufacturing process is able to concentrate the planktonic state bacteria, in a liquid form, to a point 100,000 times greater than most commercially available products and up to 100 million times greater than the usual concentration of sessile bacteria from fecal matter in wastewater.


Because bacteria multiply with time, IPT takes full advantage of the time available by adding the IPT concentrate to the outermost reaches of the sewer system, to minimize the time the fecal bacteria have to multiply in the system. IPT bacteria are also added continuously to ensure that the competitive advantage, once gained, is maintained. The reinforcement of the “good guys” allows them to dominate and suppress the “bad guys” so that odors, noxious and corrosive gases are reduced or eliminated.


Remember the pump station “heel?” That amount of wastewater remaining after the pump shuts down? IPT bacteria work extremely well in the pump stations because they quickly grow to large populations in the wastewater between pump cycles. Once established, the heel provides a large planktonic state starting population many times greater than the sessile bacteria added by incoming fecal material. The continuous addition of IPT concentrate in addition to the heel further ensures that the IPT bacteria will always be the majority. When this wastewater is pumped downstream, the extremely large IPT bacteria population dominates the biofilm on the inside of the piping and the process continues until all the sewer system is dominated by the IPT bacteria.


The domination of the sewer system by the IPT bacteria suppresses the growth and activity of bacteria that produce noxious, odorous, and corrosive gases. Reducing or eliminating the corrosive gases stops the destruction of the piping and other sewer system mechanical components and greatly increases the useful life of the system. Some estimates place the expected increase at five to ten times! While reductions in noxious and odorous gases are usually noticed in places that once had a foul smell and then no longer have that smell, the increase in sewer life has no such direct indicator. You will only notice sewer life increases when you don’t have to pay more taxes or user fees to fund the replacement or see the streets blocked off while the collapsed sewer pipes are being replaced.


What I have just written explains how IPT works in the first patent to improve the operation and maintenance of the sewer system by changing the biofilm reducing the production of undesired gases. When IPT is in place on a sewer system, you now have a sewer slime dominated by IPT facultative bacteria together with an enormous population of IPT bacteria that are planktonic and fast-growing as they flow towards the treatment plant. Without IPT you would not have this incredible increase in the total number of bacteria, nor would they be largely planktonic and facultative. The next discussion covers some of the aspects of the second patent that deal with the improvements in the treatment plant process.


The wastewater in the sewer system has some oxygen in it when it leaves the home. However, unless oxygen is continually added, which it is not, the oxygen is quickly consumed by the aerobic and facultative bacteria resulting in anaerobic conditions in the wastewater, commonly referred to as “septic” conditions. Even the gravity piping, which is exposed to air, does not get enough oxygen to always be aerobic. Another important factor is that oxygen cannot penetrate very far into the slime or biofilm layer. This means that even under aerobic conditions in the sewer, the biofilm next to the piping surface will be largely anaerobic or septic. This is where the sulfate-reducing bacteria, (the ones making smelly, corrosive, hydrogen sulfide gases) live. How can IPT bacteria get to the bottom of the slime to compete with these bad guys? The answer is that the IPT bacteria, by virtue of the fact that there are so many of them and that they like to use the same food and nutrients as the bad guys, simply eat the food before it can get to the bad guys. Without proper food and nutrients, the bad guys cannot make the hydrogen sulfide gas, nor multiply.


So, we have IPT bacteria growing quickly and eating the food and nutrients available. They will increase faster than the sessile bacteria from fecal material because they are planktonic and will quickly reach the point where there is not enough food or nutrients to keep them growing fast. And, remember, this is done almost entirely under anaerobic conditions, so even though there are lots of bacteria being produced, there are only a fraction of the number present compared to what would have been produced if all this food was consumed at the treatment plant by aerobic bacteria.


With more food and nutrients consumed in a way that produces fewer bacteria in the process, we will have fewer final bacteria to deal with. The final bacteria from wastewater treatment are commonly referred to as sludge (biosolids). So, now you see one means that IPT reduces final sludge at the treatment plant.


How can IPT increase treatment plant capacity? There are several parts to the answer. One is that because there is more treatment going on in the sewer system, there is less for the treatment plant to do. This is pretty obvious. A second part has to do with the proportions of bacteria present in the wastewater when it enters the treatment process.


A treatment plant without IPT gets all its “new” bacteria from the sewer. These bacteria are a mixture of bacteria types; however, since the conditions in the sewer are almost exclusively anaerobic, the anaerobic bacteria make up a large portion of the incoming bacteria. At the treatment plant, they only cause problems in the primary and secondary treatment steps because they die and are not easily removed. Also, some places in the treatment process where sludge is handled can become anaerobic and allow them to cause odors.


Because wastewater treatment is an aerobic process, plant operators struggle constantly to maintain conditions favorable to the aerobic bacteria. The steps used try to remove the anaerobic bacteria and keep mostly the aerobic and facultative bacteria; however, since new anaerobic bacteria are coming from the sewer all the time, the task is a difficult one.


IPT suppresses the number of anaerobic bacteria and greatly increases the number of facultative bacteria. This means that the mixture of bacteria entering the treatment plant using IPT is very high in facultative bacteria while very low in strict anaerobic ones. Because the IPT bacteria are selected to work together, they immediately switch to the aerobic state and begin their work on a cooperative, efficient basis. Remember that there is less waste material to process because of IPT work in the sewer, so this very efficient bacteria mixture has much less material that they must consume.


With IPT there is less food and nutrients to consume, more bacteria capable of consuming the food and nutrients, and much fewer bacteria that are simply “in the way.” There are many other important improvements to the treatment process from using IPT; however, those just mentioned are the most obvious. Additionally, there are bacteria in the IPT concentrate that work to totally consume fats, oils, and grease. This starts in the collection system and allows the treatment plant to process the byproducts produced by breaking down the material. Keeping grease from blocking the sewers is a great improvement, but allowing the treatment plant to completely process it is even better. This combustion of the grease can improve the final disinfection of the effluent too.


This concludes the explanation of IPT in the municipal system. I hope it has been helpful and informative. For those that might ask, “Does IPT work on septic tanks?” the answer is definitely. Remember, fecal bacteria are sessile and IPT bacteria are planktonic. IPT will work to vastly improve septic tank operation but only if it is added in the correct amounts on a daily basis. The difference between a pump station and a septic tank is that the septic tank is totally full and overflows while the pump station fills and is mostly emptied. The same principles apply to each, and we will write more about septics later.

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