Here are some reasons we continue to recommend subsurface drip disposal:
Drip systems are easy to install.
Unlike traditional drain fields or chamber systems, SDDS don’t require major excavation or backfill. The flexible drip tubing can be vibraplowed into undisturbed dirt from a spool to a depth of around 8″1.
Photo credit: Geoflow
Subsurface drip systems can be installed in shallow soil.
Because they slow-rate apply water just below the soil’s surface, they can overcome some limiting conditions such as shallow depth to bedrock.
Drip disposal can be installed just above a seasonal high-water table2.
With the right level of pretreatment, some states allow as little as 6″ of separation between the bottom of the drip line and a seasonally wet soil layer.
Subsurface drip disposal fields can be smaller than traditional drain fields.
Aqua Tech’s wastewater systems clean the water before it reaches the ground. This means the dispersal system doesn’t have to do the cleaning.
The absence of organics in the discharged effluent eliminates the possibility of field failure3.
Because they’re shallow buried at the root line, up to 80% of the water is taken up into the grass cross and disposed via evapotranspiration. This takes some of the burden for water absorption off of the soil.
Drip systems can be configured for non-discharge or beneficial reuse applications.
Perhaps the greatest concern associated with the disposal of domestic wastewater into a subsurface disposal system is over nitrogen. When nitrate concentrations over 10 mg/L reach the aquifer, public health is threatened. If high concentrations of ammonia nitrogen reach a surface water way, environmental health can suffer. Fortunately, plants need nitrogen and phosphorus. Drip systems can be designed to eliminate the risk of contamination by these nutrients by distributing treated effluent to a crop at the rate of agronomic uptake per the table below. Between evapotranspiration and agronomic uptake of nutrients, drip systems can be configured to eliminate potential discharge of wastewater to the environment4
Other surface discharge systems such as spray or overland flow can serve this same function although they usually require more space and are more expensive than SDDS. ↩︎
While every state is different, you’ll need to know the answer to the following two questions to get a wastewater discharge permit:
Question 1: What kind of discharge will it be?
Your state will want to know how much water you intend to discharge, where it’s coming from (e.g. houses, stores, restaurants, etc.), where you plan to dispose of it, and how clean it will be when it’s disposed of. Most of the time, the level of required treatment will be determined by where it will be discharged. Here are some options:
Subsurface
With subsurface discharge systems, much of the treatment of the wastewater is performed in a disposal system such as a traditional septic drain field or sand mound. Generally speaking, these permits are the easiest to obtain because they count on established technologies that don’t require much operation or maintenance. However, discharges of large quantities of primarily treated wastewater have the potential to degrade quality of ground water. Many states impose an upper design flow limit on subsurface systems, or they require pretreatment of the wastewater before it is discharged to a drain field.
Some states such as Georgia and Connecticut have issued GeneralPermits that expedite the approval of subsurface discharges. Other states likeNorth Carolina and Tennessee have privatized the approval of large subsurface disposal systems.
Land Application
This might sound the same as subsurface discharge, but it’s not quite the same. Higher volumes of wastewater can be disposed under a Land Application permit. The water usually must be treated at least to secondary levels before disposal. Because of this pretreatment, Land Application permits can also include surface application such as with spray irrigation or overland flow. These disposal methods can overcome concerns over aquifer contamination associated with subsurface disposal systems. They also have some drawbacks related to a higher potential for public exposure to treated effluent.
Subsurface drip dispersal system illustration. Note the depth of the drip lines and the nutrient uptake into the grass.
Land application of treated sewer water can virtually eliminate the risk of environmental degradation. Because of this, these permits are sometimes referred to as “non discharge.” In most cases, applicants should consider disposal to the land first. Though, sometimes, this isn’t feasible where non-infiltrative soils or other environmental factors require large swaths of land and sizeable impoundments for the application and storage of treated effluent.
Direct (Surface Water) Discharge
Open discharge of treated domestic sewer water to a waterway must be permitted under the National Pollution Discharge Elimination System (NPDES) as administrated on the state level. Some states have their own version of the NPDES permit such as Texas’ TPDES, New York’s SPDES, and Arizona’s AZPDES permits. But a clean water law by any other name still smells like a challenge.
NPDES permits are notoriously difficult and time consuming to obtain. This reputation is more or less deserved from state to state. In states like Louisiana, and South Carolina that have general permits for open discharge, it’s less deserved. In states like Connecticut or California, it’s more deserved. Regardless of the state, though, open discharge systems must hit stringent treatment targets that must be maintained through vigilant monitoring.
A direct discharge system being installed in Branson, MO
Besides the difficulty of navigating the regulatory red tape, NPDES permits presume access to a waterway. And that waterway might have to meet certain criteria. Some states, like North Carolina, require that a stream can be proven to always provide some dilution to the treated discharge before an NPDES permit can be approved. Other states, like New York, allow discharges to intermittent waterways but require the effluent to be highly treated beforehand. Sometimes a discharge will be disallowed to a large waterway because it’s already polluted. Before an open discharge can be approved, a waste load allocation must be available from the EPA.
Beneficial Reuse
Treated sewer water can be reclaimed for a variety of uses that include dust reduction at construction sites, crop irrigation, or fire suppression. To qualify for these uses, the water must be treated to a very high level. In many cases, for instance, it must be disinfected until it is completely sterile. This level of treatment can make the wastewater system significantly more expensive than one designed for surface water discharge.
From 474 mg/L to 3 mg/L BOD5. This diagram shows the treatment process calculations along the way.
Aqua Tech’s BioTankcan hit reuse standards in every state. If you’d like an estimate on one, just click the button below:
In some states, such as Arizona and Montana, concern over aquifer recharge can make beneficial reuse a preferable option despite the higher cost.
All of these discharge details come under the “administrative” portion of any permit application. In most cases, you will need a state-licensed environmental engineer to fill out the administrative section of the wastewater permit.
Get an Engineer Referral
Aqua Tech doesn’t employ permitting engineers, but we know some great ones! If you need an engineer that can design and permit a wastewater treatment system, just let us know.
Speaking of engineers, while Aqua Tech performs the job-specific design engineering for each biological treatment reactor we sell, we count on local P.E.s to perform the overall design. These folks do the siting of the system and put everything together in one place. Which brings us to the second question to be answered on a wastewater discharge permit.
Question 2: How will you clean the sewer water?
The other side of the wastewater discharge permit coin is the technical section. Most of the time, state environmental agencies will have one team to review the administrative side of the permit and another to review the technical side.
Like skinning a cat, wastewater treatment can be performed in many ways. While your engineer will perform the overarching design, they might defer to the end user to select the preferred treatment technology. If you plan to permit a decentralized sewer system for a development or a town, it’s important that you participate in the selection of the technology. That’s because you’re the one paying for it and because you or someone do business with will be responsible for its performance over the long haul.
Here’s a small sample of the design documentation we provide:
Just as important as picking the right equipment is picking the right equipment provider. That’s because regardless of which engineer you engage for permitting, they will need to partner with the equipment provider to complete the technical section of the discharge application and their final engineering report. An incompetent or unresponsive equipment provider extend the permitting process at best. At worst, they can leave you holding the bag with a non-compliant treatment technology.
There are several companies of various sizes that provide wastewater treatment and disposal equipment. It’s always best to reach out to several for an initial discussion and budgetary price. We don’t mind a little competition, we know we have the best equipment and service for the best price!
You can call or email us directly to see for yourself.
Most states in the US publish design flow charts to stipulate the capacity of wastewater systems. Here’s a list of residential and commercial design flow charts for new construction organized by state.
These documents have been downloaded from various regulatory agencies. Jurisdictions for any particular job will vary. Aqua Tech makes no certifications regarding the veracity, applicability, or relevance of the documents listed below.
Contact us for more on how to plan the wastewater component of your particular project:
So, you’ve got that piece of land and you’re ready to start developing. Here are some things you might need to know about RV park sewer systems.
1. RV park sewer systems have a big job.
RV’s are made to use less water. That’s great! Unless you have to treat their waste. Less water means less dilution. Less dilution means higher strength wastewater.
Wastewater strength is commonly measured in biological oxygen demand (BOD). That’s the amount of oxygen it is take out of the environment for biological processes. Household wastewater contains around 250 mg/L BOD. The raw influent entering an RV sewer system can be as high in BOD as 1000 mg/L.
Since septic tanks only reduce BOD by 30% RV parks discharge up to 700 mg/L BOD into their drain fields. That’s a lot of pollution entering the environment and potentially into the aquifer.
Aqua Tech wastewater treatment systems remove pollutants from RV wastewater before its discharged to the environment. We can take that 1000 mg/L RV raw influent down under 10 mg/L. That’s better than most municipal systems.
a process flow diagram depicting the treatment of high strength wastewater to a high level
2. RV park wastewater systems probably need a discharge permit.
In most states wastewater flows beyond that which is produced by a large single-family home must be permitted through an environmental protection agency. You will likely need a state-licensed engineer to write the permit. If you don’t have an engineer, we can probably refer one to you. Just give us a call.
As part of the permitting process, the engineer will determine influent parameters based on samples taken from the actual flow for a current RV park or based on modeling assumptions provided by the state. The engineer will also determine effluent limits based on regulatory guidance for the location and discharge type.
Once they have collected the data, they’ll send us the design criteria and we’ll design a system to meet them.
They’re too expensive for a couple of reasons. First, the sewerage to get the wastewater from the RV sites to the wastewater treatment plant costs too much. Gravity sewers often require high-diameter pipe, manhole covers, wet wells, and lift stations. All that can up to hundreds of thousands of dollars spent before you welcome your first guest. Aqua Tech sells STEP Collectionsystems as a modular, low-cost alternative to gravity collection systems. Since RV design flow can be considerably lower than residential flows, developers can often get up to 4 sites on one STEP system.
The second reason wastewater systems are too expensive is the approach most vendors take to designing and deploying RV sewer systems. Many wastewater treatment system providers produce one-size-fits-all systems that don’t actually fit your needs. The high overhead and material cost of these systems can kill the ROI on your development.
A newly installed wastewater treatment system for an airstream resort in Utah
We frequently recommend subsurface drip disposal (SDD) systems to dispose of treated RV park wastewater. SDD systems discharge nutrified water to a grass crop under low pressure. This means you can use the greenspace around your RV park for your disposal field.
The treatment system has arrived!
Our systems can treat RV park wastewater to surface water discharge standards. By removing most residual nutrients and contaminants our systems can safely dispose sewer water to a stream, river, or lake.
There are lots of other disposal options that your engineer might recommend. We can work with them to make sure the effluent will meets compliance requirements for whatever works best.
Click below to see some of our recent RV Park projects.
Aqua Tech’s biological process carries out complete sewer sludge treatment eliminating the need for a clarifier.
This sewer sludge treatment is based on biofilm technology. Biofilm is a dense community of attached-growth microorganisms living on specially designed plastic media. Having direct contact with wastewater, biofilm absorbs and oxidizes pollutants thus providing treatment. Multiple biozones ensure that an appropriate biological system develops according to the nature of wastewater composition. It supports dynamic balance on its own both in mass and qualitative composition according to variations of wastewater parameters (within the range of optimal adaptation rates and allowable values of design loadings).
Multi-Chamber Design
Multiple chambers in our bioreactor create a series of ecosystems in which the excess biomass is digested and mineralized in successive chambers by higher level microorganisms. This process converts organic sludge into carbon dioxide, water and inorganic elements.
Each chamber houses specialized media to host the required microorganisms.
The first chamber of the bioreactor houses a smooth-surface floating media. The smooth surface coupled with high turbulence in the first chamber prevents high biofilm accumulation on the media.
Sloughed biofilm travels into the next chamber to be consumed by protozoa inhabiting porous media (Bio-Chip).
The Bio-Chip media mitigates biofilm overgrowth as the chips rub against each other under aeration. These unfavorable conditions on the outside of the Bio-Chip cause microorganisms to inhabit primarily the protected interior of the media. Treatment in this chamber is provided by slow-growing bacteria such as ANAMMOX which produce negligible biomass.
Subsequent chambers facilitate the development of a complete trophic system with all four trophic levels. This means that the amount of bacteria are controlled by Protozoa and Metazoans that consume any surplus bacterial biomass.
The last chamber utilizes static media and minimal aeration intensity to ensuring high efficiency adsorption and mineralization of any residual suspended matter.
The above described is the conceptual model or ideology of the bioreactors which does not change if a bioreactor has just two or three chambers. Thus, any our biological process is designed so that effluent biomass amount is within the required effluent limit for TSS.
BioTank, Aqua Tech’s biological reactor, is the best value in wastewater treatment for residential and commercial development as well as for small to midsized communities. The following product details demonstrate BioTank’s durability, versatility, and efficiency.
A BioTank hot off the manufacturer’s floor
Aqua Tech’s BioTank bioreactors range in capacity from 160 GPD to 80,000 GPD. They can be installed modularly to build systems with a capacity over 1 million GPD.
Our stainless-steel package systems operate with minimal maintenance for decades. They provide a timely and cost-effective alternative to site-built treatment facilities.
Construction:
The BioTank is a factory-made, multi-chamber aeration tank made of stainless steel AISI-304. It is equipped with fixed and floating media and an aeration system comprised of an air compressor, snorkel, regulator valves, hoses, and oxygen diffusers.
The various chambers facilitate the growth of stage-specific microbes ensuring progressively higher levels of treatment through each chamber.
AISI-304 stainless steel construction allows for above ground and inground installation.
State of the art media provides maximum biofilm surface area which results in smaller bioreactors that treat up to municipal standards.
The aeration system ensures optimal oxygen conditions for advanced biological wastewater treatment.
Biological Reactor Applications in Wastewater Treatment
As a biological reactor, BioTank isn’t suitable for treating water from sources with high concentrations of chemical contaminants such as storm water, drinking water treatment centers, boiler houses or factories.
The BioTank treated effluent quality allows its safe discharge into the environment or reuse for irrigation or other technical needs.
A pristine waterfall at an RV and cabin resort with over 200 units serviced by one little BioTank.
General Provisions
Installation of an Aqua Tech system with BioTank biological reactor will require:
Site prep including a poured concrete pad for the BioTank, drainage areas and access roads
Dedicated electrical power supply (usually 3-phase)
Specialized onsite treatment systems for all local sources of wastewaters which do not correspond to the BioTank application terms
Wastewater should be primarily treated prior to be pumped to the BioTank. The primary treatment should include mechanical treatment (coarse solids and grit removal), FOG (fats, oils and greases) removal, wastewater settling and flowrate equalization.*
Process Specifications
FOG (fats, oils, and grease) Removal
FOG level should be constantly monitored, preferably by means of sensors.*
Amount of FOG enter the BioTank should not exceed 50 mg/l.
If FOG concentration is permanently higher than 50 mg/l in any of local discharges, then it is necessary to apply specially selected biopreparation for FOG decomposition, for example, BioEaseTM4210.
If FOG concentration exceeds 100 mg/l, then it is necessary to build a local grease trap and use the biopreparation for FOG degradation.
Overhead diagram of a wastewater treatment system for mixed-use featuring two BioTanks operating in tandem.
Coarse Solids Removal
The feed pumps should be protected from coarse solids present in wastewater. Depending on a primary treatment technology Aqua Tech Systems offers a solution for the removal of coarse solids.
Grit Removal
Wastewater usually contains certain amount of grit and other mineral substances, which should be removed before wastewater feeding to the BioTank.
Primary Settling
Suspended solids (SS) concentration limit for biological treatment based on the biofilm process is 105 mg/l. As raw wastewater usually has higher SS content (> 105 mg/l), primary settling should be introduced.
Primary Sludge Accumulation and Digestion
Primary sludge volume and odor are significantly reduced through the addition of a biopreparation such as Bacti-Bio 9500.
The sludge level should be constantly monitored by means of an automatic sludge level sensor or manual Sludge Judge device. Sludge removal and disposal should be handled by a certified contractor as needed (usually every 3-5 years).
Flowrate Equalization and Feeding
Aqua Tech installs flowrate equalization systems to minimize BioTank size and maximize performance.
Wastewater equalization enhances biological treatment by minimizing shock loads, diluting inhibiting substances, and stabilizing pH.
The assumed wastewater feeding duration to the BioTank is at least 18 hours/day.
The assumed feeding volume is:
v = Qday / 18, m3/hour, where Qday is wastewater amount per day
Aqua Tech Systems provides necessary settling-digestion and wastewater flowrate equalization tanks of the required volumes which are plastic or ferro-concrete.
A combination settling and equalization tank being installed in Alabama
Phosphorus Removal
If required, phosphorus is removed during primary settling through the addition of coagulant.
Biofilm cannot remove more than 1-1.5 mg/l of phosphorus. The formed biocenosis of the biofilm, being in a state of dynamic equilibrium, does not produce biomass and, accordingly, does not consume phosphorus.
Wastewater processing with coagulant ensures efficient organics reduction and reduces the phosphorus below 1.0 mg/l.
Where required, Aqua Tech provides a coagulant dosing apparatus at the primary treatment step.
Biological Treatment
Process Characteristics
BioTank’s biological wastewater treatment process is based on the biofilm technology. Biofilm is a dense community of attached-growth microorganisms living on specially designed plastic media. The surface of the biofilm treats wastewater by absorbing and oxidizing pollutants. Multiple biozones within the layers of the biofilm create a self-cleaning, self-sustaining ecosystem. The biofilm develops the microorganism diversity necessary for maximum treatment in each application. Due to efficient ecosystem development in the BioTank there is no excess biomass growth.
Technology
Incoming organics are sequentially oxidized by isolated biocenoses of microorganisms living on media retained within the borders of each aeration chamber. The media is submerged in water.
Oxygen supply and mixing are provided by aeration.
Due to change of oxidation rate at each process stage – from high on the first stage to low on the last stage – the loads on biocenoses and water saprobity vary from high to low accordingly.
In response to changing environmental conditions and amount of dissolved oxygen, the treatment process occurs as follows:
Stage One – sorption and oxidation of dissolved organic matter, adsorption of suspended solids and colloids and hydrolysis (fermentation) of suspended solids and colloids
Stage Two – sorption and oxidation of dissolved organics,
Stage Three – biofiltration (biosorption)
Process flow diagram for a commercial application with heavily contaminated influent.
Oxygen Conditions
Oxygen supply is provided by aeration. The oxygen mode is a function of organic load, biofilm density and thickness, and wastewater temperature.
The required amount of dissolved oxygen for each process stage should be optimized and adjusted according to the Aqua Tech Systems recommendations at start-up and follow-up analysis.
The corresponding environment allows formation of layered biocenosis. The layers are determined by the amount oxygen diffusion into the biofilm.
The biofilm surface is the aerobic layer which creates conditions for heterotrophic microorganisms to partially oxidize and reduce ammonium along with oxidation of organic matter.
The internal mass of the biofilm is the anaerobic layer that creates conditions for development, growth and accumulation of specific autotrophic microorganisms (ANAMMOX) which oxidize and reduce the main part of incoming ammonium.
Floating biofilm media from 440 M2 of biofilm per cubic meter to 5000 M2
Biofiltration (Biosorption)
Biofiltration or biosorption occurs in the BioTank on a static media.
In low load conditions bacteria release a significant amount of exopolymers capable to capture and retain solids during contact. In turn, solid substances captured by the biofilm (bacteria, organic matter) serve as a food for predators and detritophages that results in reduction of suspended solids amount.
It should be noted here that bacteria and predators create symbiotic relationship after a number of successions, under which predators regulate their quantitative and qualitative composition in a strict accordance with incoming food amount.
Also the significant input in clarification comes from attached stalked ciliates (Peritrichia). The peritrichs provide themselves with food by filtering large amounts of water. One individual is able to consume up to 30,000 bacteria per hour. This way peritrichia provide a high degree of biological disinfection, destroying pathogenic microorganisms.
Low organic load and high amount of dissolved oxygen in the biofilter provide partial ammonium removal.
Ammonium bio-oxidation is carried out in two stages, by two types of chemoautotrophic bacteria:
2NH4+ + 3O2Nitrosomonas = 2NO2- + 2H2O+4H+
2NO2- + O2Nitrobacter = 2NO3
Start-Up
Formation of the biofilm occurs spontaneously based on the set and maintained level of dissolved oxygen in each chamber. The biofilm reaches dynamic equilibrium as it develops through the initial operating period. Once this happens treatment process performance meets the project requirements.
Under conditions of actual loadings correspondent to the design specifications biocenoses fully mature:
For “B” bio-oxidation process – within four weeks
For “N” bio-oxidation and nitrification process – within one year.
The actual treatment efficiency should be at least 95.99% of the calculated one.
If necessary, the achievement of treatment quality for the process “N” can be accelerated by the use of methanol. Methanol provides an additional food source for heterotrophs which thereby multiplying their population. Due to lack of oxygen, heterotrophic microorganisms use oxygen from nitrates, thus reducing oxidized nitrogen. In this case it is possible to reach at least 90% of all required parameters within 60 days from start-up.
Wastewater contains nitrate and phosphorus which are nutrients that plants need to grow. Usually, nutrients are good things, but growing population density can result in too much of a good thing being deposited into streams, rivers, and other waterways. When this happens, plant life takes over – crowding out the habitats of fish and other aquatic life. As these plants die and rot, they can change water PH and bacterial levels.
To stop eutrophication, wastewater treatment systems need to greatly reduce or eliminate the amount of nitrate and phosphorus which they return to the watershed in their effluent. Governmental agencies set concentration maximums and enforce them through regular testing.
For the most part, nitrate and phosphorus can be reduced below regulatory thresholds through biological processes known as denitrification and mineralization. Advanced wastewater treatment systems use highly concentrated populations of beneficial bacteria to digest nitrate and phosphorus. The former is then released as nitrogen gas and the latter, collects in the tank as part of the sludge.
Even after advanced treatment, trace amounts of nitrate and phosphorus can frequently be found in wastewater effluent. Where mandated, further treatment can completely prevent even these from reaching the watershed.
If you’re in need of a wastewater system that will prevent eutrophication, let’s talk!
Drip irrigation systems are an efficient and proven technology many communities use to recycle and dispose of treated wastewater. The effluent is applied to the soil slowly and uniformly from a network of narrow tubing, placed in the ground at shallow depths of 6 to 12 inches in the plant root zone.
Because water is such a precious commodity, recycling wastewater can have both economic and environmental benefits for communities. Reusing wastewater to irrigate land can help protect surface water resources by preventing pollution and by conserving potable water for other uses. This is particularly important where community water supply sources rely on wells. The more water that is pumped from wells and discharged as effluent into a stream or other surface water, the less will be available to recharge aquifer or groundwater sources upon which future well water supplies rely.
Another benefit of applying wastewater to the land is that the soil provides additional treatment through naturally occurring physical, biological and chemical processes. Irrigating with wastewater also adds nutrients and minerals to soil that are good for plants and it helps to recharge valuable groundwater resources.
Residential developments with low building density required by septic drain fields contribute to an undesirable sprawl and limit land available for playgrounds, hiking trails, and other open space amenities. Spray systems, while superior to septic, can also limit land use since they produce aerosols that require large buffer zones.
Community sewers that use drip irrigation consolidate undersoil treatment into one region of the subdivision. This region can provide a visually appealing common area for the development. Achieving higher land use densities with desirable open spaces are important and shared goals of land use planners, environmentalists, and developers alike.
Soil reuse systems require less monitoring and thus lower operating costs when compared to surface discharge.
Additionally, subsurface discharge expedites the acquisition of state and county permits by addressing potential concerns of downstream property owners removing any reason for them to contest approval.
Beneficial reuse through drip irrigation is just another way we’re equipping responsible growth. Click the button below to see how we can equip you.
Increased building density. They don’t require big drain fields on each lot.
Longer lasting. Land disposal through drip irrigation doesn’t become spent through built-up solids like septic leach fields.
Much better for the environment. Decentralized systems treat wastewater through accelerated natural processes, thereby eliminating water-borne pollution.
Advantages over municipal systems:
Sooo much cheaper! Decentralized systems reduce or eliminate the need for miles of large diameter pipe and lift stations.
No smell. Designed to be small and efficient, they treat so fast that there’s no detectable odor outside of a few feet from the system.
They facilitate development in growth areas without increasing tax burden or contributing to suburban sprawl.
They keep water in local aquifers rather than sending it downstream.
One of the biggest challenges to implementing comprehensive land use plans is how to accommodate new development in locally designated growth areas that do not have public sewers. Many rural and suburbanized towns in the US face this question.
They want to direct growth to the most suitable areas of town – near existing services, such as fire stations and schools, for example – but have no prospect of gaining access to public sewer lines. New development must rely on soils, usually on a lot by lot basis, to handle wastewater. The conventional wisdom says that means low densities of development, negating the effectiveness of a growth area. However, towns and counties without public sewer systems have options that they may not realize.
Additionally, watersheds in the United States reflect tremendous diversity of climatic conditions, geology, soils, and other factors that influence water flow, flora and fauna. There is equally great variation in historical experience, cultural expression, institutional arrangements, laws, policies and attitudes. With regards to wastewater issues, it would be a mistake to impose a standard model from the federal level to address the needs on a local level. Correspondingly, centralized sewer systems are aging, frequently underfunded with respect to replacement costs and expensive to maintain. In addition, centralized sewer strategies are increasingly challenged by environmental and social considerations such as inter-basin transfer issues, aquifer depletion, nutrient loading and urban sprawl.
Decentralized wastewater management has the potential to be the catalyst for the re-creation of our institutions, to support a new agenda, and for rapidly building a flexible infrastructure to sustain the integrity of the natural systems that are essential to a healthy economy.
Tom Bartlett – founder and Ceo of aqua Tech
The new emerging civic agenda of smart growth, community preservation, open space planning, ecologically sound economic development, resource conservation, and watershed management demands that we rethink what constitutes assets and liabilities. With a capacity of roughly 200,000 gallons per day, these off-grid plants can be constructed at a cost of well under $3,000 per home. These are economic, environmental and quality of life issues and they do not lend themselves to single purpose solutions. They require local community based consideration within the context of flexible multipurpose planning.
Statistics have shown us that within the U.S., twenty-five percent of existing residential real estate and forty-seven percent of new construction are served by onsite treatment systems. Many of these systems are acknowledged to be inadequate with respect to soil absorption, nutrient removal, resource protection and public health. Ironically, despite these statistics and EPA policy changes, most regulatory codes as well as most municipal and commercial planning continue to consider onsite systems to be temporary solutions awaiting a centralized sewer hookup.
Looking beyond the traditional assumption that wastewater is simply a matter of safe disposal and the public health; the real contemporary wastewater issues are the economic and environmental issues in which the public has a primary interest:
Drinking water quality
Deterioration of recreational water resources and other natural systems services
Property Values
Economic development in small and rural communities
Urban sprawl
Beyond just disposal, decentralized wastewater management has the potential to contribute to the formation of an infrastructure to sustain watershed integrity. Decentralized wastewater treatment serves the “watershed agenda” and the principles of “community preservation” and “sustainable development.”
When approaches to the larger wastewater issues are successfully accomplished everyone benefits:
Local communities win open space zoning, water quality and supply protection, increased development capacity and an expanding tax base.
Natural systems are sustained through prudent zoning and reduction of non-point pollution.
Developers win additional lots for development and higher margins typically associated with conservation subdivision design and municipal infrastructure.
Regulatory agencies win because they gain partners in compliance management such as the municipality and perhaps a watershed authority.
Citizens and homeowners win because property values are enhanced as schools, healthcare providers, and retail outlets crop up around the new infrastructure which decentralized systems provide.
There are no major obstacles to a decentralized infrastructure for wastewater treatment.
New technologies in a properly managed context provide the opportunity for a land based watershed initiative that could significantly reduce small flow point source discharges such as those associated with onsite treatment systems. A decentralized wastewater management infrastructure should include:
Clustered, performance-based, decentralized wastewater management systems
Industrial & commercial pretreatment prior to discharge to existing sewage treatment systems
Wastewater reuse systems
Estimates suggest that this infrastructure is achievable with technologies that require 50% to 70% less space with corresponding reductions in cost of 40% to 50%. For citizens in small and rural communities these reductions represent opportunities to preserve water quality, to stimulate economic development and job formation and to restore property values. Essentially, we are shifting from large sewage collection systems and centralized treatment plants to small and decentralized management systems. Keep in mind also that this is not an alternative to centralized sewer. Rather, it is a complimentary adjunct to the existing infrastructure.
Moreover, the decentralized solution is coming from local community and watershed needs. It is not coming from the bureaucracy. It is essentially good old bottom-up American pragmatism. It is important, therefore, that the general population becomes informed about the benefits of the decentralized approach. We must find a suitable mechanism to accelerate the progress to support watershed management. If we can not find such a mechanism, we run the risk of letting the limited existing strategies (centralized and onsite) dominate the next 20 to 30 year cycle.
With every project being considered for an Aqua Tech System, planners must consider many factors in the selection of an appropriate site specific wastewater collection system.
Such as:
Housing density and road frontage
Size of the project and wastewater volume to be conveyed
Topography and sensitive natural resources
Depth to bedrock or groundwater
Distance to the wastewater treatment and dispersal site
The Settling Tank getting a final inspection
During the design process of your system the following methods should be considered:
Conventional gravity systems (with lift stations as required)
Septic Tank Effluent Gravity (STEG) system (AKA small diameter gravity sewers)
These collection or conveyance systems often represent the major portion of the total capital cost associated with any wastewater system, so careful consideration should be made to avoid extraneous expense while also ensuring reliability and environmental compliance.
Let us help you design a system that takes everything into account.
Several places around the US are currently experiencing a construction boom and we’re delighted to be a part of it. Here’s a mixed use system that our engineers have just designed.
This system is designed to treat 37,000 gallons of wastewater per day.
This particular system was designed to treat residential and commercial wastewater at the same time. Notice that the effluent (outflow) discharges at ground level. This is a septic system with no leach field!
Here’s the secret:
This private wastewater treatment plant removes nearly all of the Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), and Total Nitrogen (TN).
Our STEP system creates a pressurized, small pipe influent delivery structure to the treatment plant which eliminates the need for the expensive piping and lift stations that gravity systems require. This means that developers can cut their cost as well as defer some of that reduced cost of the community wastewater system until lots are sold. Since each home shoulders some of the load associated with wastewater treatment, the initial cost and maintenance can be distributed to the homeowners as well.
Beyond reducing development cost, STEP technology further enhances effluent water quality by leaving the majority of the solids at the point of origin where they can degrade through anaerobic processes. The effluent leaving the tank at the home then becomes the influent which the next component in the Aqua Tech system will treat through aerobic processes.
