Advanced Wastewater Treatment

Can I Get a Wastewater Permit?

The short answer to “can I get a wastewater permit” is, “Probably.”

EPA (Environmental Protection Agency) logo

The discharge of treated sewer water is regulated by the EPA under delegation to state environmental agencies.

Every state has its own set of clean water regulations which guide the permitting of wastewater treatment systems.

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.

Illustration of a cluster septic system for a neighborhood

Some states such as Georgia and Connecticut have issued General Permits that expedite the approval of subsurface discharges. Other states like North 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.

Treated wastewater spray irrigation system spray head

Subsurface drip dispersal systems retain the benefits of shallow application without the concern over public exposure.

Subsurface drip dispersal system illustration depicting shallow drip lines, evapotranspiration, and nutrient uptake.

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.

Surface water discharge wastewater treatment system installation
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.

Turnkey wastewater treatment system process flow showing solids handling and high-level effluent standard
From 474 mg/L to 3 mg/L BOD5. This diagram shows the treatment process calculations along the way.

Aqua Tech’s BioTank can 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.

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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.

State Design Flow Library

Our Growing Design Flow Library

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:

Commercial wastewater treatment plant installation

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.

tandem wastewater treatment tanks front view with air snorkels and influent pipe
The tandem treatment tanks

This is our Design Criteria Form:

3. Most RV Park Sewer Systems are too Expensive.

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 Collection systems 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

4. You have options for disposal.

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.

wastewater treatment system delivered to an RV park
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.

How Much Does a Sewage Treatment Plant Cost?

“How much does a sewage treatment plant cost?”

It depends…

One of the first questions we get asked, is “How much does a sewage treatment plant cost?” That’s a reasonable question. And we love answering it! That’s because our top-quality systems are also some of the least expensive on the market. Don’t believe us? Click the button below to get an estimate for your particular project and then shop around.

Every Aqua Tech system is custom designed around each project. Our sewage treatment plants must meet local design standards while serving the particularities of each application. Factors such as collection type, design flow, and disposal method all play into the system design. And the system design determines the price.

In asking, “How much does a sewage treatment plant cost,” it’s important to remember that size matters.

Wastewater treatment systems, like a lot of other products, are subject to the economy of scale. Price per gallon goes down as the system size goes up.

Like in the diagram, the effect is more pronounced as the system size gets smaller. A 2000 gallon per day system might cost 3x as much per gallon as a 20,000 gallon per day system which might cost 30% more per gallon than a 40,000 gallon per day system.

The economy of scale in this case means that smaller systems require the same planning, design, construction, installation and startup time as do the larger systems. So, if you ask, “How much does a sewage treatment plant cost?” We’ll first need to know, “How big?”

It’s also important to remember that not all sewage is created equal.

Commercial wastewater is typically higher strength than what comes out of your home. RV Parks, for instance can produce raw sewage with a BOD (biological oxygen demand) of nearly 1000 mg/L while concentrations in residential wastewater average around 250 mg/L. Higher strength wastewater requires more biofilm media, larger bioreactors, and bigger tanks to reach mandated effluent limits.

Location (location, location) affects wastewater system price.

Several local conditions such as fast perc rates, high water tables, high quality, or impaired waterways call for stringent treatment levels even for subsurface disposal.

The Chesapeake Bay for instance, has been designated by the EPA as an impaired waterway. That means wastewater discharge in its watershed must be treated to municipal wastewater treatment standards or better.

process flow diagram for an mbbr wastewater treatment plant treating to under 2.5 mg/L TN

This is a process flow diagram for a system to be installed in the Chesapeake Bay Watershed. It requires special appurtenances (add-ons) to ensure reduction of total nitrogen to under 2.5 mg/L.

process flow diagram for an mbbr wastewater treatment plant treating to under 2.5 mg/L TN

That’s a heckuva lot of reduction for a system discharging subsurface.

Sometimes location affects the way treated effluent must be disposed.

The soil in the eastern two-third of Texas, for instance, absorbs very poorly. TCEQ (Texas Commision on Environmental Quality) consequently mandates a soil application rate (SAR) of no more than .1 gallons per square foot per day for subsurface drip disposal systems. That means drip disposal outside the crosshatched counties on this map can cost three times as much as the national average.

TCEQ subsurface disposal guidance map.

Disposal method affects how much a sewage treatment plant will cost.

Aqua Tech’s wastewater treatment technology is so advanced that we also sell surface water discharge systems. With surface water discharge you can do away with a disposal system altogether. That means the system will need to treat to a higher level and include disinfection. But even with those additions, surface water discharge systems price out around 10% less than subsurface disposal systems in most cases.

wastewater treatment tank with integrated controls
The Southside School wastewater treatment reactor with UV disinfector.

Getting there can be half the savings.

The cost of a sewage treatment plant is only part of the overall cost of developing your sewer infrastructure. Sanitary sewers needed to convey the wastewater to the system can cost significantly more than the treatment and disposal systems together. Many Aqua Tech customers have found they can save a ton of money up front and over the long run with STEP Collection. And because STEP Collection eliminates the need for a large settling tank at the treatment works, it can save you money on the treatment system as well.

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The short answer is, “Yes.”

However, it’s not very common. While several apartment units might share a single large septic tank, they still each need enough lateral lines to treat their effluent. So, a single apartment building would need several acres of leach field. An apartment complex would need to devote over half the land to wastewater treatment.

Advanced wastewater systems are a better option for apartments outside the reach of sanitary sewers. Because they treat septic effluent in a biological reactor rather than in the ground, they can reduce the acreage needed for disposal.

Here’s an example of apartment complex wastewater treatment that works :

Aerial photo of an apartment complex with wastewater effluent drip field labeled to show size
Upon entering this apartment complex, you drive past the clubhouse and wind by a lush slope. Spoiler: it’s the wastewater drip field.

Here’s the satellite view for scale:

Satellite view of an apartment complex with wastewater drip field outlined.

If you’re making plans to develop property into apartments, give us a call. We can help you make the most of the space.

Wastewater systems in the US are sized based on the maximum number of gallons per day they can treat.

A 300-room hotel, for instance, might require a 50,000 gallon-per-day system. Depending on soil loading rate*, that system might need a 2 acre drip field for effluent disposal.

An installer walking inside a wastewater system drip field dosing tank.
Every component in our systems must account for design criteria.

Here are some factors that determine how many gallons per day your community septic or other wastewater system must be able to handle:

  • Capacity in gallons per day is determined by state and local design specifications.
  • These regulatory agencies calculate required treatment capacity in terms of maximum gallons used per person per day or maximum flow per bedroom per day, etc.
  • Commercial wastewater systems use more complex formulas that take their specific usage into account. The hotel mentioned above might need to account for 75 gallons per bed per day but might also have a restaurant and a bar attached for which another 12 gallons per seat per meal would have to be added.
  • Design criteria must also assume the level of pollution present within wastewater from different sources. Very dirty wastewater takes longer to treat which means systems must have higher capacity than what is released to give the system the time needed.

Here is an example of a design criteria matrix from an actual state regulatory agency:

An example design criteria table for wastewater system capacity in residential and commercial applications.
Design criteria differ based on locality.
  • Design criteria tables such as the one above provide a starting point to determine size, but in most cases, regulatory agencies grant variances based on actual flow and treatment level.
  • We at Aqua Tech will research the design criteria required for your project and budget around them. As the build gets closer, we reevaluate your treatment needs and work with civil engineers and regulatory authorities to ensure regulatory compliance without excess expense.

Bottom line: Use this table to get a rough estimate. When you’re ready, let’s talk and get more specific.


*Soils differ in how much moisture they can absorb per hour. Very dense soil might only be able to absorb one tenth of a gallon per square foot every hour while porous soil can absorb almost a full gallon per square foot. Soil absorption per hour is called its “loading rate.” The higher the loading rate the smaller the drip field needed.

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).

Got an enquiring mind? Here’s an overhead view of the same sewer system design:

Here’s what a similar system looks like in real life:

Wastewater treatment plant overhead view
A 3-tank in-ground system with a methanol doser and all-weather controls

Whether you’re an engineer or a real estate developer, we can help you put together a system to meet your needs. Just click the button below!