Septic Tank Treatment for Odors and Conditioning RID-X Review

By Bruce Hardboss, PE

Have you ever had your septic tanks Sinks, showers, etc. produce a foul smell like rotten eggs? The rotten egg smell is due to the production of Hydrogen Sulfide.  I used to constantly deal with a rotten egg smell from my house’s showers and bathtubs. I tried to use various septic tank treatments such as RID-X®. The RID-X® septic tank conditioner did nothing for the rotten egg smell and did not help the performance of my septic tank which required pumping every two to three years or so.

As a professional wastewater engineer, I took it on myself to solve this problem. Hydrogen Sulfide is produced by bacteria in my septic tank and supply lines in anaerobic conditions. Basically, in the absence of Oxygen,  the anaerobic bacteria use mineral compounds present in their environment to basically breath. As the more efficient compounds are used up (ones that have a higher energy yield) you are eventually only left with Hydrogen sulfide producing compounds.

The use of RID-X® or similar compounds are limited to enzymes and do little for supplementing the minerals and compounds which the anaerobic bacteria need to metabolize. So RID-X® or similar dry compounds do little to treat the “smell.”

I have discovered NORWECO Bio-Gem® organic digester about eight years ago. Bio-Gem® is a liquid product, which is loaded with beneficial bacteria (which are engineered to digest solids and grease) and a high concentration of the top tier nutrients and compounds. These nutrients and compounds promote good septic tank health and prevent the production of

Scheme of septic tank

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Hydrogen Sulfide.

Bio-Gem® has solved my septic tank pumping problems (I have not had to pump my septic tank in over 6 years, vice every two years without), and moreover, there is absolutely no odor being produced from anywhere in my septic system.

As a professional engineer, I strongly recommend the use of Bio-Gem® on a regular basis. Bio-Gem® minimizes septic tank pumping and eliminates septic system odors. Also, Bio-Gem® can be used in homes and businesses on city sewers to unclog supply lines and also it prevents odors. Try it you won’t be disappointed.

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Essential Residential Leach Field or Drain Field Construction And Operation

by Bruce Bosshard, PE

When designing a properly functioning residential wastewater treatment system, most wastewater disposal schemes include some sort of leach field. The wastewater leaving a standard septic tank is considered primary treatment. Many people can find information on residential wastewater treatment with septic tanks and leach fields. The primary wastewater treatment includes the separation of solids (see our previous articles), and some sort of minimum water treatment. The “standard United States septic tank” treats to approximately 50 biological oxygen demand (BOD) and a total suspended solids (TSS) of about 100 (50/100) with a total nitrogen loading of about 45 mg/L.Water from the septic system flows right onto the field. The waste water is absorbed through the soils surrounding the field. The leach field acts as a living biological processing machine, as well as a liquid receptor. These biological processes treat the waste water further; so then it is at an acceptable concentration before it reaches either the groundwater, or potable drinking water sources.

The general structure of the fields are usually a layer of 4 feet to 2-4 inches of leach rock. Then there is a leach line that is put over the top of the rock, and then buried with 3″ of the same rock. A geo-textile type barrier is then put on the leach rock to prohibit dirt and debris from clogging the rock underneath. Usually leach rock is covered with a minimum amount of 12 inches of native soil.

There are generally two types of leach fields; a leach trench or a leach bed. A leach trench ranges from 1-ft in diameter to 3-ft in diameter and has a maximum length of about 100-ft. a leach bed can be up to 20-ft wide and up to 100-ft long. Leach beds are generally used for larger commercial wastewater treatment disposal systems which need higher daily flow rates.

Many fields are supposed to be designed to function for a thirty year life span; which is in the worst of conditions. Leach fields are a biological processing plant that will break down into wastewater over time. When wastewater enters a field, the water has a high BOD, which is considered anoxic. Anoxic means that there is no oxygen present. While the waste water is flowing through the fields and in the soil, the biological oxygen demand dwindles down to the point that there is enough oxygen to move into an aerobic condition. Under this condition is when the bacteria levels are in a safe range.

Another item to mention is the biological activity at the rock and soil boundary continues through the life of the field. When the bacteria life cycle continues, the foreign material from processing lays on the rock and soil boundary. The material combines with clothing fibers that cannot be broken down, such as polyester, and it forms a low permeable layer. People call this layer “matting”. The mat grows as it ages, which is the reason why fields have a 30 year life expectancy.

At the end of the fields life, it is usually expanded by adding more leach area, or it is replaced. This process is costly and very disruptive. There are several products out today that are added to promote the health of the field, as well as rejuvenating the field. A major problem is the septic tank health which has grease and oils to pass through to the field. Greases and oils increases the speed of the mat growth. This results in causing earlier line replacements. There are two types of conditioners for septic tanks: liquid biologically active products, and a dry enzyme product, which is like RIDEX. Wastewater engineers like to use liquid digesters as they work better. One brand that engineers use is NORWECO Bio-germ Organic Digester. When the health of the tank is good, it minimizes the forming of matting, and prolongs the life span of the field.

When dealing with a leach line which has reached or is approaching its end-of-life (excessive matting build up) there are numerous products out there which make a lot of performance claims. Some products claim that they can fracture the soil-matting with high pressure or harsh chemicals. These products attempt to raise the permeability of the soil-rock boundary. These processes are usually temporary and fail when the matting grows back together. I prefer adding enzymes to the waste stream before the water enters the leach field. The best way to do this is to add a tablet feeder to the leach line, between the septic tank and the leach field. In this case the wastewater is directly dosed with an active enzyme just before entering the leach field. The enzyme is engineered to effectively break down the matting and to restore the leach field to its near original condition. Obviously, if there are excessive synthetic fibers in the matting, then break down of the fibers is very hard to accomplish. In most cases, the direct dosing of the water stream is quite effective. In my experience, I have not seen a case where the direct dosing using a NORWECO Bio-Perc or similar product did not work.

In summary, you should try to take care of your complete septic system. Use good septic system conditioners and if you are in a failed leach line scenario, then I would recommend using both a conditioner and a continuous direct dosing approach. The combinations of both approaches should be quite effective and extend your complete septic system life. Also, the cost associated with septic tank pumping has escalated over the last five years or so, so a good septic tank conditioner can greatly reduce septic pumping frequency. I used to have to pump my septic tank every 2 to 3 years. Since I’ve been regularly using a conditioner, I have not pumped my septic tank for over 5 years. It saves you money.

Our seasoned engineers give straight answers on residential leach field repairs. See us at our site for free advice on leach field repair.

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Residential Wastewater Treatment Leach Field – Drain Field Design and Repair

by B. Hardboss, PE

When an engineer creates a residential wastewater treatment system that functions properly, many of the disposal schematics have a leach field included. Primary treatment is considered when the residential wastewater leaves the standard septic tank. The first wastewater treatment in the system is the separation of solids (as in other articles), as well as secondary wastewater treatment in the tank’s 2nd compartment. A “Standard United States Septic Tank” can treat the wastewater to around fifty BOD, which is known as the biological oxygen demand, and the total suspended solids, also known as TSS, which to about 100 mg/L, and a concentration of total nitrogen at around forty-five milligrams per liter.

Water from the septic system the wastewater flows right into the leach field. The waste water is absorbed through the soils surrounding the field. The leach field acts as a living biological processing machine, as well as a liquid receptor. These biological processes treat the waste water further, to acceptable concentration before it reaches either the groundwater, or potable drinking water sources.

The general structure of the field has a layer of around four feet of 2-4 inch rock. From there, a line will be placed on top of the leach rock, and then will be covered with three inches of the same rock. There is a geo-textile barrier that is put on top of the rock to prevent any dirt and other foreign material from clogging up the rock below. Many times the rock is also covered up with twelve inches of soil.

The fields come in two different types: a leach bed or a leach trench. The trenches range from around one foot in diameter, to around three feet. The maximum length of a trench is around one hundred feet. The beds can range from twenty feet wide to a hundred feet long. Large industrial wastewater treatment disposal systems usually have leach beds. This is because the systems have a higher flow rate per day.

Leach fields are generally designed to function for a 30-year life span, under the worst conditions. The leach field is actually a biological processing plant which further breaks down the wastewater. Generally, the wastewater entering the leach field has a high BOD and is anoxic (essentially no oxygen present). As the wastewater flows through the leach field and the surrounding soils, the BOD is reduced to the point that there is sufficient excess oxygen to transition to aerobic conditions. Under aerobic conditions, the bacteria rapidly reduce contaminant levels to safe ranges.

One key note is that the intense biological activity at the boundary of the leach rock and the soil continues over the life of the field. As the bacteria life-cycles continue, debris from the process settles at the rock-soil boundary. This debris combines with some non-digestible clothing fibers, for example polyesters, and forms a low permeable layer. This layer is commonly referred to as “matting”. The matting tends to grow with age, and is the primary reason for a 30-year projected leach field life span.

When a leach field approaches its end-of-life, the field is generally expanded by adding additional leach area, or replaced. This can be quite disruptive and costly. There are products on the market with can be added to promote leach field health, and possibly completely rejuvenate the field. Firstly, one of the major problems can be septic tank health and the pass-through of grease and oils to the leach field. Grease and oils can speed up matting growth and cause early leach line replacement. There are basically two types of septic tank conditioners, liquid biologically active products and dry enzyme products like RIDEX. As a wastewater engineer, I prefer the liquid digesters since they seem to work better. I professionally use NORWECO Bio-gem organic digester, which has worked the best for me. Ongoing good septic tank health minimizes matting formation, and extends your leach field life-span.

When people need to deal with a leach line or bed which is at the end of its life span (a build up of excessive matting), there are products on the market that have many performance claims. Some manufacturers say that they will be able to fracture the soil matting by using harsh chemicals, or with high pressure. These methods attempt to increase the permeability of the soil rock boundary. Many of these processes will fail, or they will work temporarily. The matting will grow back together after a length of time. Waste water engineers prefer to add live enzymes prior to the the water entering the field. The popular method of adding the enzyme tablet is to use a tablet feeder that will drop it into the waste water. If there are many synthetic fibers contained in the mat, then breaking down of the fibers will be very difficult to do. This enzyme breaks down the matting and can restore the field. In many cases, this method works well. Some engineers say that direct dosing is most effective when using the NORWECO Bio-Perc enzyme, or a similar version.

In conclusion, people need to start taking care of their complete septic system. There are many good conditioners for septic systems out there, and if someone is in a failed leach line example, then they need to try using a continuous direct dosing approach with a good conditioner. When people combine both of these approaches, they will have a higher success rate, which will also prolong the septic systems life span. Another item is the cost of pumping a septic tank has increased in the past 5 years, so using a good conditioner for the septic tank will reduce the need to pump the system often. Some people used to have their septic tank pumped every two to three years.When people need to find out more information about residential wastewater treatment with septic tanks and fields, it is good to ask a waste water engineer, since they will have all of the information to keep septic tank systems running efficiently.

New Technology Selection Of Residential Wastewater Treatment Packaged Plants


by Bruce Bosshard, PE

BnB Engineering conducted a review of residential wastewater treatment systems on the market today. Our review picked Norweco Singulair as the top manufacturer. Norweco wastewater has been in operation for over 100 years. During this period, NORWECO has continuously improved wastewater products from basic residential septic tank designs, and then extended aeration systems which have evolved into the NORWECO SINGULAIR line of products. The SINGULAIR line of products has superior wastewater treatment performance, including built-in; 1)Robust effluent filtration, 2) Wastewater De-nitrification, 3) Chlorination capabilities and UV Disinfection, 4) De-chlorination capabilities, 5) Flow Equalization, 6) Wastewater treatment capabilities to U.S. drinking water standards., 7) Low costs, 8) 50-year warranty exchange program

BnB views NORWECO SINGULAIR as the best residential wastewater treatment packaged plant on the today’s market. GEOFLOW, a leader in drip irrigation products, is teamed with NORWECO to provide add on drip irrigation products. GEOFLOW recognizes that SINGULAIR’s top residential wastewater treatment performance is unparalleled. The best wastewater treatment performance, including de-nitrification (NSF 40 certified) sets NORWECO well above extended aeration competing systems. In BnB’s final decision, we included NORWECO SINGULAIR’s competitive pricing, demonstrated NSF-40 certified performance, a long track record (100 years) in continuous improvement and innovation as key factors.

The following is a general Discussion on our Pick. To provide a robust wastewater treatment system you need to incorporate the following into the basic design; 1) One-day pretreatment, 2) One-day aeration/extended aeration, 3)Flow equalization, 4) Filtration, 5) Tertiary treatment for de-nitrification, 5) Built-in Chlorination and De-Chlorination

All NORWECO SINGULAIR systems include a minimum of 1-day wastewater pretreatment. NORWECO requires stringent quality assurance. One key to SINGULAIR success is that standard precast tank molds are used by all distributors. This standardization makes certain that there are little variations from one caster to another. Competing systems often allow concrete tank casters to use existing molds. Holes are generally cut in each tank and their one-size fits all units are placed in the holes. These competing systems lack the conformity of SINGULAIR systems, therefore, their performance is not always consistent. In SINGULAIR systems, pretreatment is accomplished by requiring a minimum of 1-gallon solids separation tank capacity for each gallon of maximum daily wastewater flow. SINGULAIR designs ensure that larger packaged systems increase solids tank capacity accordingly. The basic SINGULAIR systems are 600, 750, 1,000, 1,250, and 1,500 gallons per day (GPD). Each configuration mandates that pretreatment tank capacity is increased accordingly. NORWECO provides ALL distributors with approved concrete molds which ensure tanks are always the same. This mandate ensures adequate stage-one residential wastewater treatment and consistent NSF-40 performance.

Similar to pretreatment tank capacities, minimum aeration tank volumes are increased according to maximum estimated GPD flows. The increase in aeration tank size promotes a minimum of 1-day aeration. Also, as aeration volumes are increased, the number of aerators are increased to ensure adequate aeration capacity (1,000, 1,250, and 1,500 GPD units have two aerators.). NORWECO SINGULAIR utilizes a stirring technology (the only moving parts) which minimizes the airflow into the system. The low airflow (2-4 cubic feet per minute (CFM)) minimizes odors which are generally associated with extended aeration systems. The aeration flow dissipates into the surrounding soil, which minimizes smells from the systems. Competing systems, that we looked at, use excessive air-flow (over 20 CFM) to stir the wastewater. This continuous-high-airflow rate causes bad odors in the general area of the pipe outlet. Also, when the tank is continuously aerated, there is no possibility for de-nitrification, since the anoxic conditions are required for de-nitrification.

Flow equalization is accomplished by maintaining the Bio-Kinetic (BK) module height within +/- one inch. The SINGULAIR TANKS are constructed with about 6-inches of minimum free board. The BK-module has a series of small holes in each side of the module. As tank level increases, slow flows of wastewater are allowed through the holes. The systems can easily be expanded to multiple treatment units, if designs ensure that all the treatment units are at the same elevation. BnB refers this configuration as a treatment node. Here the SINGULAIR system can be expanded to much larger treatment nodes, with limits at about 6,000 GPD.

The BK module also promotes superb filtration and de-nitrification. To reach stringent NSF performance requirements for total suspended solids (TSS), SINGULAIR BK modules possess a robust group of contact discs which in turn precipitate out the vast majority of TSS. Once again, the BK module design and style is patented and can’t be integrated into competing systems. We’ve observed effective BK module filtration up to 1. 5 years of operations, without servicing. The comprehensive filtering capability in the SINGULAIR BK module provides this robust promise. Competing devices evaluated depend on straightforward filtration for example bags or filters which are high priced as well as require quarterly check up, cleansing and-or replacing. The SINGULAIR BK modules have numerous “stacked plates” that are comparable to commercial clarifiers. The stacked pates enable de-nitrifying bacteria (anaerobic bacteria -absence of oxygen) to fill the plates. The FE, slowly and gradually flowing residential wastewater flow, passes within the plates and the micro organism decreases the nitrogen or de-nitrifies the treated wastewater flow. This revolutionary approach has demonstrated, in some designs, to lower total nitrogen to under 5 mg/L (drinking water standard is less than 10 mg/L total nitrogen).

BK-modules can be readily converted to include both chlorination and de-chlorination. The top of the BK-modules are constructed to receive tubes which can be fitted with chlorination or de-chlorination tablets. Since the BK-modules provide low-equalized-flows, the tubes utilize specially formulated tablets that function well at low flow rates. The Chlorination/de-chlorination tubes cost about $75 each. Therefore, for about $150 the systems can be converted to chlorination disinfection units. This is a very cost-effective option. A few states, including TX requires that FE, reliable chlorination, and filtration devices be added to the effluent of most competing systems. NORWECO gladly provides them BK-2000 modules. The BK-2000 is a small tank that contains one BK-module. In re-use applications, this add-on allows the competing systems to perform at more-reliable and higher standards.

We consider NORWECO SINGULAIR costs as highly competitive. The NORWECO SINGULAIR systems are distributed locally by authorized NORWECO distributors. Costs (controlled locally by the NORWECO distributor), for a single family residence (up to 600 GPD wastewater flow) range from $3,500 to about $5,000 per unit. The NORWECO SINGULAIR GREEN systems cost approximately $800 to $1,000 more per system, depending on location. The advantage of the SINGULAIR GREEN system is that it can be transported to remote areas and placed with a standard backhoe (weighs approximately 1,000 pounds). Please send us a comment; if you are interested in SINGULAIR or SINGULAIR GREEN systems. We directly service the northern Arizona, southern Nevada and California areas (http://www.wastewatertreatmentplant.org/). Please contact us or NORWECO directly at NORWECO.com.

Residential Septic Tanks – Leach Fields – Drain Fields – Why and Alternatives

 

 

 

By B. Bosshard, PE  _  www.wastertreatmentplant.org


As a professional engineer, I generally receive questions on the why’s and how’s of wastewater treatment. First we need to ask why we need treatment. Then discuss the minimum requirements which are generally accepted to minimize polluting our environment. Our next discussion explores the Environmental disadvantages of using septic tanks, and finally what are some of the alternative septic tank solutions in use today.

Why Treatment?

First we need to ask, “Why do we need to treat our wastewater?” In the old days we merely dug a hole and place an “outhouse” on top of the hole. We would then deposit our biological waste directly into the hole.  When the hole became full we would just move the “outhouse” and cover up the waste, dig a new hole and place the “outhouse” over the new hole. In this scenario, the waste does not readily break down, and can remain toxic for 100’s of years. The waste can readily be exposed by digging animals, or leach down to the surrounding groundwater. Both paths promote pathogen pathways directly to us, which can readily spread disease.

To minimize our wastewater effects on the human and other animal populations we can take a few steps to allow the wastewater to naturally break down, reducing health risks. The most common and least expensive method is the use of Septic Tanks. The septic tanks are configured to take all our wastes, biological and wash waters (Black and white waters) combine them into a tank (of adequate size) and then discharge the treated wastewater to the surrounding soil.

 

 

 

 

Minimum Requirements:

Tank Sizing

Generally, minimum septic tank sizing is specified as 2.1 times the maximum expected daily flow. This size promotes the wastewater to slowly flow through the tanks, requiring about 2 plus days to exit the tank. This process is commonly referred to as “residence time.” Furthermore, the tanks are constructed to allow the solid wastes to be removed first and then further treatment of the off-liquid is treated in a separate chamber. The first tank compartment is generally referred to as a solids tank, or “chunk tank.” Here the lighter solids like toilet paper floats to the top and heavier particles and solids settle to the bottom of the tank.

A pass-though line, about 4-inches in diameter, allows solid-free water to flow to the second tank compartment for further treatment. Generally the first tank compartment is 60 to 70 percent of the total tank volume.

Build up of anaerobic bacteria (bugs that live without oxygen) in the two tanks treat the wastewater continuously. I usually put up a fuss when my wife pours chlorine into the toilets to clean them, since the chlorine has a tendency to kill the beneficial bacteria in the septic tank.

The treated wastewater that exits the tank flows to a leach bed. A leach bed is designed with a 30-year life consideration. The size of the leach area is generally driven by the soil conditions. Obviously, a sandy, more permeable soil will require less leach area to serve the system. Generally the leach line, or bed is constructed with a 2 to 4-ft layer of 1 to3 inch rock. A perforated leach line is place on top of the leach rock, covered with leach rock and then a geotextile layer to keep dirt from clogging the leach rock below. Then the leach field is covered with about 12 inches of native soil.

In considering a 30-yr. life span of the leach area we must consider that the leach field will clog up over time. As the wastewater is deposited into the leach field, further biological activity occurs and a matting-like layer forms at the bottom and sides of the leach field. This layer generally expands with time, so at the end of a 30-yr life, the leach field cannot take all the wastewater volume produced by the residence. There are treatments available which will dissolve this layer. I prefer the NORWECO Bio-gem and Bio-perc products to restore leach field health. We will discuss leach field and septic tank treatment and conditioning in subsequent articles.

 

 

Soil Conditions

Soil conditions are crucial to ensure that the wastewater has enough time in the soil to remove the majority of pathogens and other toxic components. Generally, a minimum vertical separation from a limiting area is drawn at 10-ft. A limiting area is where no further treatment of the wastewater will occur, once the wastewater reaches the limiting layer. A limiting layer can be groundwater, or bedrock, etc.

Environmental Disadvantages of Septic Tanks

Nitrogen Loading

One of the largest concerns with using septic tanks is that we load excessive nitrogen into the ground. The nitrogen loading is promoted because we do not treat the nitrogen in the process. Generally, in the United States, regulatory bodies set a minimum size developed lot for a 3-bedroom home at one-acre. This minimum size promotes an acceptable nitrogen load on the groundwater below.

Groundwater Contamination

Other groundwater contaminations are in the form of pathogens. Pathogens are usually tracked as colony forming units (CFUs) per ml. As we increase the number of homes to less than one home per acre, we also start to stress the underlying aquifers with pathogens. The soils can only take so much of a loading rate before the pathogens start increasing in surrounding groundwater wells.

Water Resources

Therefore, a down-side to septic tanks as the primary residential wastewater treatment method is the effect that it has on our water resources. The primary contamination of our groundwater comes from total nitrogen loading and pathogens. As we increase the density (the number of homes per acre) we need to consider other wastewater treatment methods to minimize the impact on our water resources and the resultant health risks to our population.

Alternatives to Septic Tanks

New technologies over the last 100 years, has significantly reduced nitrogen and pathogen loading to our environment. Wastewater treatment methods included extended aeration, De-nitrifying systems, Geotextile filters, and hybrids.

Extended Aeration

In extended aeration we can take a standard septic tank as noted above, and blow air into the tanks which will promote aerobic bacteria to form. The aerobic bacteria (bacterial that breathe oxygen) are much more aggressive than the anaerobic bacteria in standard septic tanks. The aerobic bacteria grow quickly and break down the waste much faster. The resulting wastewater stream has much lower concentrations of pathogens and other wasteproducts. Leach field degradation is greatly reduced, and can be much smaller in size and still maintain that 30-yr. plus life span.

De-nitrifying systems

Once we treat the wastewater in an extended aeration plant, we still have a lower amount of total nitrogen than a septic tank, but the total nitrogen is still high. Generally, in areas that have total nitrogen problems in groundwater, de-nitrifying systems are required to be installed on backend of extended aeration plants to further reduce nitrogen loading of underlying groundwater.  De-nitrifying systems require anaerobic conditions (absence of oxygen). Some hybrid systems like the NORWECO SINGULAIR system, utilizes a Bio-kinetic modules to promote anaerobic conditions and the further breakdown of total nitrogen before the water leaves the unit. With recirculation, the SINGULAIR system yields total nitrogen levels less than drinking water standards in the United States. BnB Alternative Septic Solutions recommends this product as the proven leader in de-nitrifying residential systems.

Geotextile filters

Geotextile filters consists of plates or filters that the wastewater flows through the filters or plates allow bacterial to form on the substrate and promotes breakdown and some dentrification of the wastewater stream. One large downside to filters or plates is that they generally require replacement in 10 years or so, due to clogging. This can be a large expense to the homeowner. We therefore, do not recommend using these products.

Hybrids

Crafty engineers are always coming up with hybrids of extended aeration, flow equalization, and geotextile filters. We are generally skeptic on claims, and look for demonstrated performance over many years, prior to endorsing many of these products. The one product we like today is the NORWECO SINGULAIR which is a hybrid system, which has evolved over the last 100 years to its current configuration. Extended aeration, combined with geo-textile technology is patented and well proven, with low costs and the best proven treatment performance on the market.