current wastewater technologies

Appendix A – Wastewater Technologies Report

Current Wastewater Technologies

An Overview for Homeowners

Prepared for the City of St. Augustine and the Florida Department of Environmental Protection, Office of Resilience and Coastal Protection, Florida Resilient Coastlines Program

As part of Grant Agreement Number R2130, Assess Vulnerability of OSTDS to SLR and Storm Surge to Develop Adaptation Plans, Ph I, Task 5 – Report of Wastewater Technologies

May 31, 2021 (Revised June 8, 2021)

Tricia Kyzar

Eban Z. Bean, PhD, PE, Principal Investigator


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Table of Contents 1. Introduction ................................................................................................................... 7

1.1. The Basics of Domestic Wastewater Treatment .................................................................................. 7

2. Treatment Requirements ............................................................................................. 10

3. Decentralized Wastewater Technologies .................................................................... 17

3.1. Tank technologies .............................................................................................................................. 18

3.1.1. Anaerobic Systems (traditional/conventional) ................................................................... 19

3.1.2. Aerobic Treatment Units (ATUs) ...................................................................................... 20

3.2. Drainfield Technologies .................................................................................................................... 24

3.2.1. Traditional rock/gravel aggregate ...................................................................................... 24

3.2.2. Engineered Aggregate........................................................................................................ 25

3.2.3. Plastic Chambers ............................................................................................................... 26

3.2.4. bric Wrapped and Bundled Pipe ........................................................................................ 27

3.2.5. In-Ground Nitrogen Reducing Biofilter ............................................................................. 28

3.2.6. Drip Distribution ................................................................................................................ 28

3.2.7. Mound System ................................................................................................................... 29

4. Centralized Wastewater Technologies ........................................................................ 30

4.1. Suspended Growth Processes ............................................................................................................ 33

4.1.1. Complete Mixing ............................................................................................................... 33

4.2. Attached Growth Processes ............................................................................................................... 34

4.2.1. Trickling Filter ................................................................................................................... 34

4.2.2. Rotating Biological Contactor ........................................................................................... 35

4.3. Further/Additional Processing ........................................................................................................... 35

4.3.1. UV Disinfection ................................................................................................................. 35

4.3.2. Chemical Treatments ......................................................................................................... 36

5. Between Centralized and Decentralized ..................................................................... 36


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5.1. STEP Systems ................................................................................................................................... 36

5.2. Cluster Systems ................................................................................................................................. 37

5.3. Package Plants ................................................................................................................................... 39

6. Costs ............................................................................................................................ 39

7. Funding Opportunities ................................................................................................ 44

7.1. Water Quality Grants ......................................................................................................................... 44

7.2. FDEP/Division of Water Restoration Assistance .............................................................................. 44

7.2.1. Federal 319 grant (EPA originated) Nonpoint Source Funds ............................................ 44

7.2.2. Clean Water State Revolving Funds Loan program (EPA originated) .............................. 45

7.2.3. Septic Upgrade Incentive Program .................................................................................... 46

7.3. Florida Resilient Coastlines Program ................................................................................................ 46

7.3.1. Resilience Planning Grant (RPG) ...................................................................................... 46

7.3.2. Resilience Implementation Grant (RIG) ............................................................................ 46

7.4. St. Johns River Water Management District ..................................................................................... 47

7.4.1. District Cost-Share Funding .............................................................................................. 47

7.4.2. Indian River Lagoon Water Quality Improvement Projects .............................................. 47

7.5. Florida Department of Economic Opportunity .................................................................................. 47

7.5.1. Florida Small Cities Community Dev elopement Block Grant .......................................... 47

7.5.2. Regional Rural Development Grant................................................................................... 48

7.5.3. Rural Infrastructure Fund................................................................................................... 48

7.5.4. Special District Accountability Program ........................................................................... 48

8. Conclusions ................................................................................................................. 49

9. References ................................................................................................................... 51

10. Terms .......................................................................................................................... 58

11. Abbreviations .............................................................................................................. 58


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List of Figures Figure 1-1 The range of wastewater treatment facilities from single, onsite septic systems to large, municipal

sewer plants. ............................................................................................................................................. 7

Figure 2-1 Process flow of a typical domestic wastewater treatment process. ........................................................ 32

Figure 3-1 Example of a conventional septic tank. .................................................................................................. 19

Figure 3-2 Example of a suspended treatment tank. ................................................................................................ 21

Figure 3-3 Example of a fixed film or attached growth tank. .................................................................................. 22

Figure 3-4 Example of a recirculating, unsaturated media tank. .............................................................................. 23

Figure 3-5 Example of a conventional septic system. .............................................................................................. 25

Figure 3-6 Example of an engineered aggregate unit. ............................................................................................. 26

Figure 3-7 Example of a chamber system. ............................................................................................................... 27

Figure 3-8 Example of a fabric-wrapped pipe. ........................................................................................................ 28

Figure 3-9 Example of a drip distribution system. ................................................................................................... 29

Figure 3-10 Example of a mound system. ................................................................................................................. 30

Figure 4-1 Example of a cluster system. .................................................................................................................. 38

List of Tables Table 1-1 Summary of Domestic Wastewater Treatment Process and Examples for Centralized and Decentralized

Facilities ................................................................................................................................................... 9

Table 5-1 Comparison of common parameters for influent, effluent, PBTS, Florida Keys Treatment Standard and

Florida Drinking Water Standard. .......................................................................................................... 16

Table 6-1 Summary of cost estimates ..................................................................................................................... 43

https://uflorida-my.sharepoint.com/personal/haldeman_ufl_edu/Documents/Documents/Projects%20-%20Eban/WWT_Technologies_Paper_03%20-%20BH%20edits.docx#_Toc68007696















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EXECUTIVE SUMMARY This report is part of a project to assess the vulnerability of onsite wastewater treatment

disposal systems (OSTDS) to climate change related impacts such as sea level rise (SLR), storm

surge, high tide flooding and rising groundwater levels. Coastal areas are at higher risk of

experiencing these impacts which puts OSTDS in these areas at higher risk of inundation and

failure. This project focuses on the City of St. Augustine and the OSTDSs in their

water/wastewater infrastructure and service area. In the study area we have identified 2,938

OSTDS all of which are experiencing rising ground water levels and many of which are at risk of

SLR, storm surge and high tide flooding. The City of St. Augustine seeks to understand which

areas with OSTDS are at greatest risk and what options might be available for reducing or

eliminating these risks.

The purpose of this report is to provide homeowners with a comprehensive overview of

current wastewater technologies, both decentralized and centralized, to provide information on

contaminant and treatment levels for different circumstances and systems, and to share cost

examples and funding opportunities. The information in this report is intended to help

homeowners participate in community discussions and plans to reduce the risks faced by OSTDS

from climate change related impacts.

The authors would ask the readers to understand that science and technology are (thankfully)

constantly evolving and that new treatment technologies may be available in the near future that

are not covered in this report. This report includes information from the Environmental

Protection Agency, Florida Department of Environmental Protection and industry professionals

in both decentralized and centralized wastewater treatment. We are pleased to have had the input


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from so many persons active in the area of wastewater treatment and appreciate the time they

spent with us.

The authors have made every attempt to recognize source material, and state that no

copyright infringement is intended and that we are sincerely grateful to all those who gave their

time to answer our many questions.


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1. INTRODUCTION

This report is intended for use by homeowners and does not go into in deep details or

explanations of the biological, physical, or chemical processes of wastewater treatment or the

science of the technologies discussed. The intent of this report is to introduce the homeowner to

the broad range of treatment technologies available for treatment of residential (domestic)

wastewater so that they may have a simple reference when considering solutions for wastewater

treatment. Common treatment processes for decentralized and centralized systems will be

covered at the general level, as will cost examples and funding opportunities. The reader is

encouraged to seek other sources for more detailed information on any of the topics covered.

Again, it is emphasized this is a very generalized, high level review, not intended for scientific or

engineering audiences.

1.1.The Basics of Domestic Wastewater Treatment

Generally, wastewater treatment systems are managed in either ‘Centralized’ and

‘Decentralized’ facilities. Centralized facilities are usually thought of as the larger municipal

sewer systems but can include ‘STEP’ (Septic Tank Effluent Pumping) systems, local ‘package

Single,

onsite

Small

cluster for

Develop

ment level

Large

municipal sewer

plant that

Small

municipal

sewer plant

Figure 1-1 The range of wastewater treatment facilities from single, onsite septic systems to large,

municipal sewer plants.


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plants,’ and even ‘cluster systems’ depending on your point of view. Decentralized facilities

include many different types of ‘onsite’ treatment systems including advanced treatment units

and performance-based units (Hallahan 2021). Think of the range of wastewater treatment

facilities as existing on a continuum from smallest to largest:

The goal of all of these systems is to break down the contents of your wastewater into

something that would not be harmful to the environment. These systems originally only

processed the waste from our showers, sinks and toilets. Now they also break down what comes

out of our clothes washers and dishwashers plus all the modern cleaning products we use,

medications we take, food we send down the garbage disposal and processed foods we eat and

unfortunately sometimes also the harsher chemicals we use such as paints or super-duty cleaners.

The processes available to treat these ‘influents’ fall within three different categories: physical,

biological and chemical (Tchobanoglous and Burton 1991). An example of a physical process is

straining to separate solids and liquids. A Biological process is using bacteria to break down

organic matter in solids and liquids, and a chemical process might include using chlorine to

disinfect effluents. Municipal systems, being bigger and more advanced, do a better job of

addressing some of the newer, chemical elements in our wastewater, but even these are not yet

advanced enough to treat everything. Onsite systems, which do not usually include a chemical

process, can be severely negatively affected by chemicals coming out of our homes and entering

our septic systems.

The most common process used to process wastewater are biological processes, and when

properly designed and maintained these are also the most efficient (Tchobanoglous and Burton

1991). Think of these as composting systems, some are just bigger than others. In the broadest

terms, domestic biological wastewater treatment falls into one of two categories: Suspended


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Growth or Attached Growth. This refers to the growth of the bacteria that are doing the work of

breaking down the waste. In a suspended growth process the bacteria are suspended in the fluid

(aka ‘liquor’), in attached growth the bacteria grow on some type of media such as rocks or a

plastic shape. In centralized systems the process may include a preliminary step that specifically

screens out materials such as sand or objects that could harm the mechanical components of the

treatment system. In some biological processes, solids are allowed to settle to the bottom, or they

are mixed with the liquids. Solids that are allowed to settle are broken down by anaerobic

processes. Liquids with or without solids, move into either the suspended growth or the attached

growth process, both of which are aerobic processes. Depending on the design of the system this

may be the final step before disposing of outputs or there may be additional steps to further

clarify or polish the effluent before it moves out of the treatment process completely.

The table below summarizes what happens in the domestic wastewater treatment process and

gives examples for how these activities are accomplished in Centralized and Decentralized

treatment systems.

Table 1-1 Summary of Domestic Wastewater Treatment Process and Examples for Centralized

and Decentralized Facilities

Stage Activity Centralized Decentralized

Pre-Treatment Screen out grit or objects that could harm the physical components of the system

Influent Screen Grit Removal Unit

Preliminary Treatment

Solids settle to the bottom; liquids move to the next step

Sedimentation Tanks or Basins

Tank in Conventional System


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1.2.Operation of Conventional Septic Systems

Conventional septic systems operate by allowing solids to settle to the bottom of the tank,

while letting liquids skim out to seep through a drainfield into below ground soils. The elements

in the wastewater that enter the tank include organics, nitrogen, phosphorous, pathogens and

chemicals/pharmaceuticals. The most common potential pollutants from onsite wastewater

treatment systems include nitrogen, phosphorous (Humphrey et al. 2014; Lapointe et al. 2015;

Lusk et al. 2017; Lusk 2018b; Paerl 2014), pathogens (Lapointe, Herren, and Bedford 2012;

Lapointe, Herren, and Paule 2017; Reay 2004; Schneeberger et al. 2015), pharmaceuticals and

personal care products (Del Rosario et al. 2014; Yang et al. 2016) although nitrogen pollution

may be the most well-recognized output of poorly functioning septic systems. It is important to

note that nitrogen and phosphorous (and to some extent FIB and some of the ingredients in

pharmaceuticals and personal care products) are naturally occurring elements in nature and only

become ‘pollutants’ when they reach harmful levels of concentration. Nitrogen is the export that

gets the most attention usually because it is often the limiting nutrient to eutrophication and

harmful algal blooms in surface waters (Humphrey, O’Driscoll, and Zarate 2010; Humphrey et

al. 2013; Humphrey Jr. et al. 2012; Lapointe, Herren, and Bedford 2012; Lusk et al. 2017;

O’Driscoll et al. 2019; Withers et al. 2014) although phosphorus can be a limiting nutrient as

Secondary Treatment

Liquids (with or without solids) are processed through a suspended growth, attached growth or combined process

Activated Sludge or Rotating Biological Contactor

ATU Tanks Suspended Fixed Film Unsaturated Media Drainfields

Tertiary Treatment

Possible additional processing for further contaminant reduction or elimination

Various Filters or Chemical Processes UV Treatment Wetland Filtration Lagoons

Performance-Based Treatment Systems Drainfields


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well (Guildford and Hecky 2000). ‘Nitrogen’ is used in the general, there are actually several

species of nitrogen involved in the waste processing cycle of septic systems including nitrates

(NO3), nitrites (NO2), ammonia (NH3) and ammonium (NH4). FIB, also used as a general term,

includes fecal coliform bacteria (e coli) and entero viruses (enterococci) which will be discussed

below.

Valiela estimated that each person in a household releases 4.8kg of nitrogen per year (Valiela

et al. 1997) and Lusk et al estimate 8.7 g/person/day or 3.12 kg/person/year (Lusk et al. 2017).

The process of converting nitrogen outputs to nitrogen gas in septic systems takes many steps

(see Figure 1.1). Wastewater leaving the house contains nitrogen with approximately 74%

organic nitrogen and approximately 24% ammonium (NH4). While in the tank, organic nitrogen

will convert via ammonification to ammonium (NH4). Effluent leaving the tank to enter the

drainfield will then be approximately 70-90% ammonium (NH4) and 10-30% organic nitrogen

(Gurpal S. Toor 2019). Once the ammonium enters the drainfield it will most likely be

converted to nitrate (NO3) via denitrification in the unsaturated soils (aka vadose zone). It may

also be taken up by plants if the root zone is within the drainfield, or it may be converted to

ammonia gas (NH3) through volatilization (when the pH in the soil is greater than 8). If there are

any negatively charged particles in the soil, the ammonium maybe adsorbed to these.

Ammonium may also be used by microorganisms for food (Lusk et al. 2017; Valiela et al. 1997).

After passing through the soils, nitrates will enter the groundwater. In this anaerobic zone

denitrification will convert nitrates (NO3) to nitrogen gas (N2). Nitrates may also be taken up by

plants or microbes in groundwater. If ammonium and nitrates are not fully processed through

nitrification/denitrification they are likely to move into surface waters where even a small

amount (1 mg/L) can lead to harmful algae outbreaks.


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Figure 1.2 The nitrogen cycle in a conventional septic system

When the full process does not happen, elevated levels of ammonium and/or nitrates enter

aquifers, drinking water wells and surface waters. For the full process to happen there must be an

adequate amount of organic matter in the unsaturated soils (aka the vadose zone) below the

drainfield and sufficient distance between the drainfield and the groundwater table (Valiela et al.

1997) (see Figure 1.1 again). There should be 24” between the drainfield and the high

groundwater table (determined by the wet season high level) and the soils should contain organic

matter capable of completing the nitrification process.


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While this is not true for all coastal communities, many are at or near sea level and have a

predominance of inorganic sandy soils. For these communities, there is high likelihood for

incomplete nitrogen conversions. When these conditions are compounded by sea level rise,

increased flooding and precipitation, storm surge, and/or rising groundwater level, there is an

increasing opportunity for incomplete nitrification and/or denitrification, enabling ammonium

and/or nitrates to enter surface waters. When there is a lack of sufficient distance and/or organic

matter between drainfields and groundwater elevated levels of nitrogen (in the form of

ammonium and/or nitrates) could enter groundwater resources and transport to drinking water

wells, aquifers, or surface water bodies. When high levels of nitrogen (>10 mg/L) enter private

drinking water wells, the potential health risks to humans can include decreased oxygen in the

blood, blue baby syndrome or even cancer (Oosting and Joy 2011; Ye 2019). When high levels

of nitrates (>1 mg/L is an adequate food source for algae to grow) enter surface waters it can

contribute to harmful algae blooms, reduced oxygen in the water, eutrophication, reduced

biodiversity and ecosystem health (Cole et al. 2006; De 2015; Wang et al. 2013; Withers et al.

2014). When algae consume the nitrates and grow to such an extent that they block sunlight from

reaching submerged aquatic vegetation (SAV), causing the vegetation to die which can deprive

fish of a necessary food source. When the algae have consumed all the nitrogen they begin to

die and through decomposition reduce the supply of oxygen in the water which can lead to fish

kills. Some algae also produce toxins that can directly cause fish kills as well as skin rashes if

humans come in contact with it (SJRWMD 2021).

In addition to nitrogen, phosphorous, pharmaceuticals and pathogens may also transport out

of systems with the effluent (Lapointe, Herren, and Paule 2017). Kramer et al estimate

phosphorus exports per person per year at 1.2 kg/person/year (Kramer et al. 2006) and Lusk et al


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estimate 1.6 g/person/day or 0.584 kg/person/year (Lusk et al. 2017) and while most of this is

exported in septic system effluent phosphorous readily binds to soils (Lusk et al. 2017) and so

does not usually pose a human health threat. This sounds good except that it only takes very

small amounts, 0.03mg/L, of P to lead to eutrophication in surface waters where P is the limiting

source (Charles P. Humphrey et al. 2014; Iverson et al. 2018; Lusk et al. 2017).

‘Pathogens,’ is the more appropriate term for pollutants that originate in fecal material

although not all are disease causing. These include fecal coliform bacteria and enteric viruses

such as enterococcus. Lusk et al estimates fecal coliform bacteria at 106-109 per gram of human

feces and enteroviruses at 103-107 (Lusk et al. 2017). The wide variety of fecal contaminants

would require specific tests for each one, making this level of testing impractical. Instead, FIB is

used to indicate the likely presence of pathogens. Pathogens in groundwater can contaminate

private drinking water wells and surface waters (Schneeberger et al. 2015; Weiskel, Howes, and

Heufelder 1996) where there is not sufficient distance in the unsaturated zone beneath drainfields

(Lusk et al. 2017). Lusk et al notes that counts for pathogenic bacteria in septic tank effluent can

be as high as 105-108/100ml for e coli and 103-104/100ml for enteroviruses. When this is

compared to the amount required for infection doses, just 10 organisms for some e coli species

and 106-107 for others, and only 1 organism for enterovirus, we can see how significant the

human health risk is from these contaminants (Lusk et al. 2017).

Recent research is also showing that pharmaceuticals and personal care products are another

export of septic systems (Del Rosario et al. 2014; Lusk et al. 2017) referred to as ‘TOrCs’ or

trace organic chemicals. A growing body of literature is revealing the danger these pose to the

environment and marine life in surface waters (Santos et al. 2013; Snyder et al. 2003). For


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example, hormones in pharmaceuticals can lead to physical and behavioral changes in male fish

(feminization) that impact diversity and reproduction (Vajda et al. 2008).

1.3.Treatment Requirements

Historically, treatment was categorized as ‘primary,’ ‘secondary’ and ‘tertiary,’ but now

treatment is focused on maximum levels of contaminants in the effluent, such as a maximum of

10mg/L of Total Nitrogen in the Florida Keys. In this way, both centralized and decentralized

treatment systems are similar, in that they have to remove a certain amount of contaminants,

although the requirements are slightly different for the two. Since this resource is written for the

homeowner we will focus on treatment requirements for onsite or localized systems.

As mentioned, what’s going into the septic system is everything from our toilets, showers,

sinks, clothes washer, dishwasher and any other plumbing in your home. What we flush down

the drain is not only organic waste from ourselves, but all the chemicals we use for cleaning,

medications we ingest that don’t break down in the body, and often times hazardous household

waste that shouldn’t go down the drain at all. There are also some surprising items that enter

septic systems that shouldn’t: coffee grounds, fats/oils/grease (FOG), cleaning wipes, disposable

diapers, kitty litter and cigarette butts to name a few (Harriss and Blanco 2013). None of these

items can be broken down in septic systems and could even clog pipes and cause the tank

contents to back up into the house. It’s important to recognize that the biological processing done

by the septic system happens almost completely in the drainfield in a conventional system. ATUs

(advanced treatment units) and PBTS (performance based treatment systems) provide increased

reductions in the tank with their new technologies and this has greatly improved effluent quality

out of the drainfield.


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To understand what level of processing takes place in these systems, the table below

compares what is going into a conventional septic tank (the raw sewage – influent – from your

home), to what is coming out of the drainfield and going into the soils below the drainfield, and

also treatment standards for PBTSs, the Florida Keys and drinking water in Florida.

Table 1-2 Comparison of common parameters for influent, effluent, PBTS, Florida Keys

Treatment Standard and Florida Drinking Water Standard.

Element Going

into the

Septic Tank

(mg/l)1

Coming

out of the

Drainfield

(mg/l) 1

PBTS

meeting

NSF 245

Standard

(mg/l) 2

Florida

Keys

Treatment

Standard

(mg/l) 1

Drinking

Water

Standard

(Florida,

Class I)

(mg/l) 3

Total

Nitrogen

60 60 50%

reduction

10 10

Total

Phosphorous

10.4 9.8 1 0.01

CBOD5/BOD 420 216 25 10

TSS 232 61 30 10

1 (Harriss and Blanco 2013), 2(Groover 2020), 3(“62-302 : SURFACE WATER QUALITY STANDARDS -

Florida Administrative Rules, Law, Code, Register - FAC, FAR, ERulemaking” 2020, 530)

We can see that there is not much nitrogen treatment happening in a conventional system, an

area of concern in Florida right now. The NSF 245 standard defines the level of nitrogen

reduction required for residential wastewater systems (NSF International 2021) and has the


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added benefit of CBOD and TSS reductions as well. In all cases, we can see that treatment is

necessary to cleaning the effluent to an appropriate level before releasing it back to the

environment.

2. DECENTRALIZED WASTEWATER TECHNOLOGIES

Decentralized Systems are systems that have historically been ‘onsite’ at the property it is

providing the waste treatment service for. While most commonly these are for single family

residential properties, they may also be for small commercial uses or a small number of homes

together. These most commonly consist of a tank and a drainfield. The tank is a watertight

concrete or heavy-duty plastic or fiberglass tank that is buried underground. Residential system

tank sizes depend on the size of the home and how many people live there. They generally start

at a 900 gallon size and can go as high as 3,000 gallons(“Product Listings and Approval

Requirements | Florida Department of Health” 2021). Everything leaving the house through the

plumbing (toilets, showers, sinks, dishwasher, clothes washer, etc.) enters the tank. Heavy solids

sink to the bottom; fats, oils, grease (FOG), and lighter solids rise to the top; and liquids

(effluent) flow out into the drainfield (US EPA 2018). The top of the drainfield should be 6”

below ground surface, and should have at least 24” from the bottom of the drainfield to the top of

the groundwater (FDOH 2018).

In these systems, a large area of concern is what types and quantities of pollutants are leaving

the tank and entering the drainfield. These ‘pollutants’ include high concentrations of nitrogen

from urine. While nitrogen is a naturally occurring element, in high concentrations it can be

harmful to plants and animals. In an ideal situation, there will be a high level of organic matter in

the soils beneath the drainfield and this organic matter will be able to convert enough of the

nitrogen to harmless nitrogen gas so that the concentrations are no longer harmful. After the


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effluent leaves the drainfield and soaks through the soils beneath the drainfield, it enters

groundwater where it eventually makes its way out to surface waters. Especially in Florida we

have seen the effects of high levels of nitrogen entering surface waterbodies, such as lakes and

rivers, from septic systems as well as other sources, in the form of algal blooms, fish kills and

reduced aquatic vegetation (Diaz-Elsayed et al. 2017).

In Florida we face several challenges to the ‘ideal’ situation. First, our soils have a high sand

content and little organic material. This allows fluids to move quickly through the soil to

groundwater with very little processing of pollutants. An additional challenge, especially in

coastal areas, is our groundwater levels are rising – reducing the distance between the drainfield

and the groundwater and thus how much of the harmful nitrogen is converted to harmless

nitrogen gas. Both of these challenges allow high levels of harmful nitrogen to enter groundwater

and make their way out to surface waters. As we saw with the centralized systems, ‘treatment’

occurs in the biological processes of suspended growth or attached growth where bacteria break

down the contaminants. For onsite systems this process has traditionally been completed in the

drainfield, but new technologies have improved drainfield treatments and introduced these

processes to the tank as well.

2.1.Tank technologies

In recent decades, tank technologies have evolved from the traditional anaerobic (without air)

treatment type to several methods of more advanced treatment processes. These range from

providing better treatment to pollutants and wastes overall, to specifically treating nitrogen or

other elements. There have also been technological advances in drainfields. These have included

the design of the drainfield pipes as well as the media below the drainfield and above the soils.


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2.1.1. Anaerobic Systems (traditional/conventional)

Anerobic septic systems are the most common and what most people think of when picturing

a septic system. They have also been around the longest. In these systems, solids settle to the

bottom and are ‘digested’ in an anerobic (without air) environment while lighter solids float to

the top and liquids flow into the drainfield and then into soils (US EPA 2018). The primary form of

‘treatment’ in these systems is whatever processing happens in the soils below the drainfield. As

noted above, in some situations this can be very little treatment.

Figure 2-1 Example of a conventional septic tank.


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Image Source: EPA, Types of Septic Systems (https://www.epa.gov/septic/types-septic-

systems)

2.1.2. Aerobic Treatment Units (ATUs)

These systems introduce air into either the primary or a secondary tank where bacteria digest

more of the components of the wastes than they do in a traditional system. ATUs come in several

different forms such as ‘Suspended,’ ‘Fixed Film,’ and ‘Unsaturated’ (Groover 2020).

2.1.2.1. Suspended Growth

In a ‘Suspended’ aerobic treatment there is an aeration tank where air is forced to move in

the liquid and bacteria are ‘suspended’ in this mixture. The moving air keeps the mixture moving

and mixing while also keeping the bacteria suspended (Goguen 2018). These bacteria are more

effective at reducing pollutants so less harmful materials make it out to the drainfield.

https://www.epa.gov/septic/types-septic-systems



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Image source: AAMS Wastewater, www.aamswastewater.com

2.1.2.2. Fixed Film/Attached Growth

A ‘Fixed Film,’ or ‘Attached Growth’ system contain material that the bacteria attach

themselves to and then the effluent are sprayed over the material by a rotating arm. This process

mimics the suspended treatment system by alternatively exposing the bacteria to air and fluids

(Goguen 2018).

Figure 2-2 Example of a suspended treatment tank.

http://www.aamswastewater.com/


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Image source: National Precast Concrete Association,

https://precast.org/2018/01/taking-septic-tanks-to-the-next-level-advanced-treatment/

2.1.2.3. Unsaturated Media Filters

Unsaturated media filters operate by filtering the effluent through a material (media) such as

sand before it goes to the drainfield. These are available in both ‘single-pass’ and ‘recirculating’

where the effluent may filter through the media only once before going to the drainfield or may

be recirculated through the media multiple times before going to the drainfield. There are several

different media types than can be used in these systems including sand, gravel, peat or foam

(Galbraith 2018).

Figure 2-3 Example of a fixed film or attached growth

tank.

https://precast.org/2018/01/taking-septic-tanks-to-the-next-level-advanced-treatment/


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Image source: Missouri Department of Natural Resources,

https://dnr.mo.gov/pubs/pub2738.htm

Performance Based Treatment Systems (PBTS) and Innovative Systems are systems

designed by a licensed engineer specializing in wastewater treatment and are often used where

site conditions require treatment beyond what a conventional or advanced system can achieve.

These systems must reach specified treatment levels for CBOD5 (five-day carbonaceous

biochemical oxygen demand), TSS (total suspended solids), TN (total nitrogen), TP (total

phosphorous) and FC (fecal coliform) (Harriss and Blanco 2013). As part of their design, they

may use components of ATUs and also additional treatment technologies such as chemical

treatments, UV lights or other technologies.

Figure 2-4 Example of a recirculating, unsaturated media tank.

https://dnr.mo.gov/pubs/pub2738.htm


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2.2.Drainfield Technologies

While the drainfield design hasn’t changed much from the traditional pipe and trench

network, what the trench is filled with and how that ‘pipe’ is constructed has seen advancement.

Also, traditionally the drainfield has been gravity fed, meaning the effluents flow downhill into

the network. Today, when site conditions prevent a traditional gravity system from operating, a

pressurized system can be installed to make sure effluent moves through the drainfield network.

2.2.1. Traditional rock/gravel aggregate

The most common drainfield design is to put a perforated pipe network in a gravel bed. The

gravel is of large enough size to allow space between the rocks for the effluent to flow through.

Bacteria will build up on the rocks and provide treatment to the effluent as it flows through (US

EPA 2018). One downside of the rock aggregate is that the ‘fines,’ smallest pieces of rock, may

be so small as to clog filtration.


25 | Page


systems)

2.2.2. Engineered Aggregate

Engineered aggregate is a synthetic material that is formed into a shape with lots of surface

area for bacteria to attach to. These are often compiled into pre-built units to make installation

Figure 2-5 Example of a conventional septic system.




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easier (Infiltrator Water Technologies 2015). These have the benefit of not having any ‘fines’ to

prevent effluent flow and increased surface area for more bacteria to attach.

Image Source: Infiltrator Water Technologies, www.infiltratorwater.com

2.2.3. Plastic Chambers

Plastic chambers are like the top half of a circle that is placed as the drainfield network.

These can be placed linearly or in the common network fashion like common perforated pipe.

Bacteria attach to the plastic chamber as well as the soil under it, building up a mat of biological

material to do the processing (Shoaf Precast Inc. 2021).

Figure 2-6 Example of an engineered

aggregate unit.

http://www.infiltratorwater.com/


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Image source: Shoaf Precast Inc., www.shoafprecast.com

2.2.4. Fabric Wrapped and Bundled Pipe

Fabric wrapped pipe is exactly what it sounds like. Perforated corrugated pipe is wrapped in

a polyester fabric. Bacteria attach to the fabric and the pipe and treat the effluent as it ‘wicks’

around the pipe (Springfield Plastics, Inc. 2021).

Figure 2-7 Example of a chamber system.

http://www.shoafprecast.com/


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Image Source: Springfield Plastics Inc., www.spipipe.com

2.2.5. In-Ground Nitrogen Reducing Biofilter

This is required in Spring and Aquifer protection areas. It is a layer of filter material

(woodchips or other approved material) below the drainfield that will achieve significant

nitrogen reductions of up to 65% (FDOH 2020).

2.2.6. Drip Distribution

A pressurized system that regulates the flow of effluent to the drainfield so that it is sent to

the drainfield in regular, even doses. This regulates the application of effluent to the soils so

there is no over or under saturation that might interrupt the bacteria cycle and potentially kill off

the bacteria mat (Hallahan 2012).

Figure 2-8 Example of a fabric-wrapped pipe.

http://www.spipipe.com/


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Image source: Ever Green Septic Design, www.egsd.com

2.2.7. Mound System

Mound systems are most commonly used when the distance between the drainfield and the

ground water, or a confining layer of soil such as clay, is not deep enough (24”) to allow for

sufficient effluent treatment (Parker et al. 2009). The drainfield is raised above ground to create

the depth necessary for treatment.

Figure 2-9 Example of a drip distribution system.

http://www.egsd.com/


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Image source: Iowa Department of Natural Resources, www.iowadnr.gov

3. CENTRALIZED WASTEWATER TECHNOLOGIES

This section will give a general description of some of the most common technologies used

to process domestic wastewater in Centralized systems. Virtually no two facilities have exactly

the same design as the final design is determined in part by the level of treatment required. The

treatment technologies described below are some of the most common for Centralized systems

and are usually used in some combination to achieve the necessary treatment.

Figure 2-1 below shows how domestic wastewater is generally handled by a centralized

facility. Some pre-treatment may happen at the water supply facility before water is consumed

by a household. This pre-treatment may remove fine particles or introduce disinfecting chemicals

not present in the water source. The public water supply is consumed by the household then

leaves the household as wastewater and is taken up by the collection system that moves it to the

wastewater treatment facility. Once the wastewater reaches the facility it may be put through a

screening process (Primary Treatment) to remove grit or objects that would harm the plants

physical components. If the facility uses an activated sludge process solids and liquids will move

Figure 2-10 Example of a mound system.

http://www.iowadnr.gov/


31 | Page

into the first treatment tank for mixing, or solids may be allowed to settle out and treated

separately from liquids (Secondary Treatment). If the facility produces bio solids that will be

disposed of separately these will be separated out and prepared for disposal (Biosolids

Treatment). Depending on the design of the facility and their treatment requirements, advanced

treatment may follow the secondary treatment. This may include special treatments for nutrients

such as nitrogen and phosphorus. Disinfection will be the last step if necessary to further remove

infectious organisms. Finally, the effluent is prepared for disposal. This may be discharging to a

local waterbody, reused for irrigation in places such as golf courses or certain agricultural

applications, or may be injected deep underground through an injection well.


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Image source: Florida Department of Environmental Protection.

https://floridadep.gov/sites/default/files/dwwprocess_0.pdf

Figure 3-1 Process flow of a typical domestic wastewater treatment

process.

https://floridadep.gov/sites/default/files/dwwprocess_0.pdf


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3.1.Suspended Growth Processes

The Activated Sludge process for wastewater treatment is the most common for suspended

growth processes. This process operates by both infusing air and preforming a mixing action of

the influent material (liquids and solids). This provides bacteria in a ‘suspended’ manner which

break down the ‘liquor’ (mixed material). The liquor moves through a series of these aeration

and mixing tanks for some period of time (hours to days), or as in the case of Sequencing Batch

Reactors, there may be only one tank for processing. Common variations of the Activated Sludge

method include ‘Complete Mixing,’ ‘Sequencing Batch Reactors,’ ‘Extended Aeration,’ and

‘Contact Stabilization’ (Tchobanoglous and Burton 1991).

3.1.1. Complete Mixing

The Complete Mix process involves a continuous flow of influents that are constantly being

mixed together. Additionally, as solids and liquids settle out at various points, a portion of each

are returned to the mixing tank(s). Some of the sludge is allowed to settle out as waste sludge. If

this process provides the necessary level of treatment, the effluent is discharged, otherwise it is

moved onto additional treatment processes.

3.1.1.1. Sequencing Batch Reactors (SBR)

Often referred to as a ‘fill and draw’ process, the SBR process happens in one tank and thus

the tank is ‘filled, the ‘batch’ is processed, and the tank is then emptied or ‘drawn’ down.

Bacteria treat both solids and liquids. After treatment, solids and liquids are separated and each

undergo additional processing dependent on how much treatment is still necessary and how the


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final outputs will be disposed. SBR is well suited for smaller plants (<5MGD – million gallons

per day) but is more complex to keep processes balanced within the batch processing.

3.1.1.2. Extended Aeration

Extended aeration is a slower activated sludge process in that the liquor mixture spends much

more time in the suspended tank. This process is good for smaller facilities that have a much

lower influent rate (< 0.5 MGD). Also, it is most commonly used in ‘package plant’ setups.

Package plants are pre-manufactured facilities that can be setup for small communities or

neighborhoods.

3.1.1.3. Contact Stabilization

Contact Stabilization refers to using aeration to stabilize the organic matter in the sludge that

is being returned to the primary mixing tank. As with Complete Mixing, influents are mixed in

the same tank, after which some solids settle out in a second tank. These solids are then contact

stabilized before returning to the primary mixing tank.

3.2.Attached Growth Processes

Whereas Suspended Growth processes keep bacteria suspended in the tank, Attached Growth

provides a surface for the bacteria to attach to. These surfaces take many forms and are made

from several materials. In attached growth processes, the focus is on how the bacteria come in

contact with the influent. The most common methods are the ‘Trickling Filter’ and the ‘Rotating

Biological Contactor’ (Tchobanoglous and Burton 1991)

3.2.1. Trickling Filter

In this method, influent is introduced into a tank containing the media upon which bacteria is

growing. The influent is ‘trickled’ over top of this media and allowed to filter through the


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bacteria on the media. Commonly these are round tanks, and the influent is introduced through a

set of arms extending from a rotating pivot point. These tanks tend to be several feet deep, often

6 feet deep. At the bottom is a collecting tank that collects solids as well as liquids. A portion of

the solids and liquids are cycled back through the tank. Treatment is achieved through repeated

cycling which places the influents in contact with the bacteria attached to the media.

3.2.2. Rotating Biological Contactor

While the trickling filter trickles the influents over the media, Rotating Biological Contactors

rotate the media through the influents. Bacteria are growing on the media which is slowly rotated

through influents in a tank. This exposes the bacteria to the influents for processing through both

an aerobic process and anaerobic process.

3.3.Further/Additional Processing

If further treatment is necessary, for disinfection or further treatment of infectious organisms,

UV disinfection or chemical treatments are available and the most common (Tchobanoglous and

Burton 1991).

3.3.1. UV Disinfection

Ultraviolet, or UV, light can be used to kill bacteria or virus by exposing the material to

either a natural or artificial UV light source. Ultraviolet light exists within a particular spectrum

on the light spectrum. It is the radiation emitted within this spectrum that can act as a bactericide

or virucide.


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3.3.2. Chemical Treatments

For chemical disinfection, Chlorine is the most commonly used chemical in wastewater

treatment. In appropriately managed processes, it can react with various nitrogen compounds in

wastewater effluent achieving a desired level of disinfection.

The processes discussed above are only some, though the most common, ways in which

centralized wastewater treatment facilities may treat domestic wastewater. Additionally, facilities

may combine any of these processes to achieve a required level of treatment. In fact, it should be

noted that rarely will there be two facilities with the same treatment design. Facility design will

be determined by what is coming in and to what level it needs to be treated. Required treatment

level will also depend on how outputs will be disposed.

4. BETWEEN CENTRALIZED AND DECENTRALIZED

Depending on the needs of the community, components of centralized and decentralized

treatment systems can be combined to create a facility that serves a small area or community.

These can include ‘STEP’ systems, ‘cluster’ systems, and ‘package plants’ (Hallahan 2021). The

benefit of these is that they can be customized to the community’s needs and can help bridge the

wastewater treatment gap for small but growing communities who may not be ready or able to

connect to a larger treatment plant.

4.1.STEP Systems

STEP Systems (Septic Tank Effluent Pumping) leave the tank in place on the property but

draw the effluent into the collection network to be treated at the central wastewater treatment

facility. Solids in the tank continue to break down through their aerobic process and can be


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pumped out periodically but the higher contaminant loads are treated with the (usually) more

advanced technology at the central facility.

4.2.Cluster Systems

Cluster systems, similar to STEP systems, leave the tank on the property to collect and

process solids, but transport the effluent to a common location for processing in a drainfield.

The drainfield can use the conventional pipe and gravel system of any of the other drainfield

technologies available. This can serve a small community of homes that may not be able to

connect to a central facility because of distance or physical barriers.


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systems)

Figure 4-1 Example of a cluster system.




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4.3.Package Plants

Package Plants, mentioned earlier under the centralized systems extended aeration

technology, are pre-built treatment facilities that can be setup and operating much quicker than a

centralized facility but are intended to serve local communities such as subdivisions or a few

thousand homes.

These local facilities can be operated by the municipality, a Special District (discussed under

funding options), or an agency created for their management.

5. COSTS

It’s difficult to pin down costs for any of these systems. What’s provided below is only for

reference and should not be relied upon as fact.

Centralized facilities usually don’t begin with a blank slate. Generally, there is an existing

facility that is looking to expand, and since each facility is a unique design costs will always

vary. if you want a 1mgd plant it might be $3/gallon, but changes with economies of scale, so

smaller package plant might be at least $5-6 per gallon for the plant. In addition to the physical

plant, there are costs for the collection system – the network of pipes around town. These costs

vary by length, number of connections, the need to install a pressurized system if there is not

enough elevation for a gravity feed system, land acquisitions or easements, road work, labor

costs, etc. The collection system may be as much or more than the plant itself (Jarrett 2021).

The City of St. Augustine has received information about several different upgrades they are

interested in. Being a low-lying coastal community, they are very vulnerable to the impacts of

climate change and their wastewater treatment facility is located in a particularly vulnerable area.

They have considered moving the facility to a different location on higher ground. This means


40 | Page

not only moving the physical treatment plant but also rerouting portions of the collection system

that brings wastewater to the plant for treatment. They estimate to build a brand-new plant would

be around $80 million not including design, land acquisition, easements or other costs not related

to the physical structure.

They have also looked at certain upgrade projects that would improve operations and

treatment. One such project would add a UV disinfection treatment which would replace an acid

treatment they currently use at the end of the treatment process. This would result in a higher

quality effluent though it would be around $800,000 to install and would pay off in

approximately 10 years.

Another upgrade project, rehabilitating the headworks, would improve the primary treatment

process where it accepts the influent. This particular project would have the benefit of enabling

them to raise some of the structures, which would make them more resilient to flooding. It is

estimated this project would cost around $4.5 million (Beach 2021).

For homeowners that may be connecting to the centralized facility, these costs generally

include connection from the road to their home. The municipality or authority usually provides

the pipe to the road in front of the property and the homeowner covers the connection from there

to the house. The cost for this varies based on how far from the road the house is. The longer the

distance the greater the cost. A conservative estimate for septic to sewer conversion may be

around $12,000. This includes removal of the existing tank and mound (if exists), restructuring

the existing plumbing and restoring landscaping (Beach 2021). In this situation there will also be

the monthly sewer bill following connection to the central facility. These fees vary too. There is

usually a flat fee plus a cost per gallon. Wastewater costs are often estimated based on water use

since there is no meter for the outgoing volume. The City of St. Augustine charges a monthly fee


41 | Page

of $15.11 for in-city wastewater plus $6.89 per 1,000 gallons of wastewater (St. Augustine

Utility Fees 2019).

For an onsite system, costs for the system are only a little less variable because the

mechanical components may have standard costs. But, similar to centralized systems, costs for

an onsite system may include: system design, shipping costs, site work and labor. System design

costs will be impacted in part by the site. If there are setback requirements that make placement

tricky, a higher performing unit may be necessary to achieve the treatment standards. Shipping

costs can be affected by the type of equipment: a concrete tank will cost more to ship than a

plastic or fiberglass tank.

For homeowners installing a new onsite system, a basic conventional system will start around

$8,000 if there are no soil or setback challenges. Soil challenges can include soils with a high

clay content that do not allow for fluids to filter through soils, or a limiting layer of clay within

the 24 inches below the drainfield. These soils will have to be replaced or amended with suitable

soils. Setback challenges may occur if the land area available for the septic system is too close to

a waterbody or private drinking well. This may result in additional treatment technologies being

added to the system. When basic systems face these challenges, it can drive the cost up over

$20,000 (Groover 2021).

Other examples of extra costs with basic systems include permit costs which can vary by

county, whether the soil evaluator is a private party of the Florida Department of Health, and fees

for inspections when extra soil work is needed.


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Also possible is the requirement of a mound system because there is not enough depth

between the ground surface and the groundwater surface. Mound systems introduce addition

costs for the additional soils, inspections and mound stabilization fees.

For a more basic ATU which may only address CBOD and TSS, this can add an additional

$2,000-$4,000 for additional permits. These systems require an operating permit and a

maintenance entity permit. Plus, the system has to be inspected once a year and have recorded

maintenance twice a year. Homeowners may become certified to perform their own maintenance

and avoid the hired maintenance costs. For ATUs with more advanced treatment (CBOD, TSS,

TN, TP), these costs can go even higher.

Systems installed within the Springs Protected Areas require an In-ground Nitrogen

Reducing BioFilter. These are can also be installed in other locations and provide nitrogen

reduction benefits. Since these systems do not have any powered components, they do not incur

the operating and maintenance fees like the ATUs referenced above. These systems may be

completed for around $10,000.

Obviously, these costs add up. Beyond installation costs there are maintenance costs. An

ATU or PBTS will provide much higher treatment quality and can be used in locations with less

land available but have higher operating expenses. They have electrical components that require

electricity to operate, they require more frequent maintenance including annual inspections and

run most efficiently during regular loading. These systems can be negatively impacted when

under heavy loading (large holiday gatherings) or no loading (everyone is gone on vacation).

Again, these are only general ballpark estimates and homeowners should get a real quote

from a licensed engineer or installer. The table below summarizes the estimates presented here.


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Table 5-1 Summary of cost estimates

Estimate example

Centralized

Large centralized facility $3/gallon

Small centralized facility $5-6/gallon

Build a new facility on higher ground $80 million

Upgrade disinfection to UV treatment $800,000

Rehabilitate headwords and raise some of the

structures

$4.5 million

Homeowner connecting to centralized facility $12,000

Decentralized

Install new conventional system beginning at $8,000,

may exceed $20,000

Install new, basic advanced treatment unit add $2,000-$4,000 to

conventional system

Install new conventional system with In-ground

Nitrogen Reducing BioFilter

$10,000


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6. FUNDING OPPORTUNITIES

Thankfully there are many funding opportunities available to help communities who are

facing upgrades to their wastewater treatment systems. The state of Florida, both directly and

with EPA funds, offers several programs. The programs listed below all support septic upgrade

or septic to sewer conversion in some way. This may be planning, design, construction or

connection. See the program for specific details.

When looking at funding opportunities, look for programs that can work together. Projects

that cross multiple phases (design and construction) may benefit from multiple funding

opportunities such as one that only supports design plus one that supports construction. This can

be especially helpful when funds must be used within a short period of time such as one year

because these projects typically take several years from start to finish.

6.1.Water Quality Grants

Offered annually through FDEP to government entities, the program distributes a total of $25

million to selected applications. There is a minimum 50% local match required unless the entity

qualifies as a ‘rural area of opportunity’ or if there is a public/private partnership pay for

performance agreement.

https://protectingfloridatogether.gov/sites/default/files/documents/WaterQuality_PFT_GrantI

nfoSheet_0.pdf

6.2.FDEP/Division of Water Restoration Assistance

6.2.1. Federal 319 grant (EPA originated) Nonpoint Source Funds

“319 Grants” refers to the section of the Federal Clean Water Act that supports these

projects. Total available funds vary each year but is usually around $8-$9 million. Funds are

https://protectingfloridatogether.gov/sites/default/files/documents/WaterQuality_PFT_GrantInfoSheet_0.pdf

https://protectingfloridatogether.gov/sites/default/files/documents/WaterQuality_PFT_GrantInfoSheet_0.pdf


45 | Page

available to local governments (county and city), special districts, water management districts,

state agencies, public colleges and universities and national estuary programs in Florida.

https://floridadep.gov/wra/319-tmdl-

fund#:~:text=About%20Nonpoint%20Source%20Funds&text=The%20program%20administers

%20both%20the,pollution%20from%20land%20use%20activities.

6.2.2. Clean Water State Revolving Funds Loan program (EPA originated)

This is a low interest loan program and segregates loans by ‘planning loans,’ ‘design loans,’

and ‘construction loans.’ Additionally, if a community qualifies as a ‘small disadvantaged

community,’ they may qualify for grants (as opposed to loans). Loans are for 20 years and the

interest rate is determined by the community’s median household income, poverty index and

unemployment index.

https://floridadep.gov/wra/srf/content/cwsrf-program

If a community has received a Clean Water State Revolving Fund loan, they may also apply

for a Small Community Wastewater Construction Grant. These must be communities with

10,000 or fewer in population with a per capita income less than the state average.


For projects that include Davis-Bacon wage rate and American iron and steel in their

projects, they may be eligible for loan assistance in the form of financing rate reductions on

construction agreements.


https://floridadep.gov/wra/319-tmdl-fund#:%7E:text=About%20Nonpoint%20Source%20Funds&text=The%20program%20administers%20both%20the,pollution%20from%20land%20use%20activities







46 | Page

6.2.3. Septic Upgrade Incentive Program

This program is currently not available because it has allocated all its funds. Funding for the

next state fiscal year is currently in deliberation so check back to see if there will be funding for

the next year.

https://floridadep.gov/springs/restoration-funding/content/septic-upgrade-incentive-program

6.3.Florida Resilient Coastlines Program

The Florida Resilient Coastlines Program offers two grant opportunities each year, the

Resilience Planning Grant and the Resilience Implementation Grant.

6.3.1. Resilience Planning Grant (RPG)

These grants are available annually to municipalities that are required to have a coastal

management element in their comprehensive plan. Funds are available for up to $75,000 and the

project must be completed within the fiscal year. Eligible projects include vulnerability

assessments (such as for infrastructure of anything that is not required for compliance with the

Peril of Flood statute), development of adaptation plans or resilience plans or for regional

collaboration efforts.

https://floridadep.gov/rcp/florida-resilient-coastlines-program/content/frcp-resilience-grants

6.3.2. Resilience Implementation Grant (RIG)

The ‘implementation’ grants are intended to be a ‘next step’ for communities who have

received a ‘planning’ grant. These grants are available to communities that have a coastal

management element in their comprehensive plan and are ready to implement the projects or

plans that have already been designed. Funds are available annually for up to $500,000 per

community and projects must be completed within the fiscal year.

https://floridadep.gov/springs/restoration-funding/content/septic-upgrade-incentive-program



47 | Page


6.4.St. Johns River Water Management District

6.4.1. District Cost-Share Funding

The District supports a cost-share funding program for projects that support core missions

including water quality. Project terms are up to two years and funding is available for up to 25%

of construction costs for water quality projects.

https://www.sjrwmd.com/localgovernments/funding/districtwide/

6.4.2. Indian River Lagoon Water Quality Improvement Projects

Available to counties and municipalities, public universities, and colleges, regional planning

councils, non-profit groups and the Indian River Lagoon National Estuary Program who are

within the district boundaries. The program provides $25 million annual to programs designed to

improve water quality including sept to sewer conversions. No match is required but is a positive

consideration during review.

https://protectingfloridatogether.gov/sites/default/files/documents/IndianRiverLagoon_PFT_

GrantInfoSheet_2.pdf

6.5.Florida Department of Economic Opportunity

6.5.1. Florida Small Cities Community Dev elopement Block Grant

This is a HUD program that provides grant funds to Florida for use in Florida small

communities to support projects that benefit communities with a majority (51%) of low to

moderate income residents. Available funds range from $18 - $26 million on a competitive basis.

These funds can be used to support wastewater improvement projects including new sewer or


https://www.sjrwmd.com/localgovernments/funding/districtwide/

https://protectingfloridatogether.gov/sites/default/files/documents/IndianRiverLagoon_PFT_GrantInfoSheet_2.pdf

https://protectingfloridatogether.gov/sites/default/files/documents/IndianRiverLagoon_PFT_GrantInfoSheet_2.pdf


48 | Page

water lines and septic abandonment in cities with less than 50,000 residents or counties with less

than 200,000 residents. There are some additional criteria that may be confusing but can be

easily explained by a program coordinator.

www.FloridaJobs.org/SmallCitiesCDBG

6.5.2. Regional Rural Development Grant

This program encourages neighboring rural counties to join together to pursue economic

and/or tourism development for the improvement of their communities. This may lead to projects

that improve quality of life for residents. There are some financial planning and match

requirements from the communities. Be sure to work with a coordinator for the best experience.

https://floridajobs.org/community-planning-and-development/community-

partnerships/regional-rural-development-grant

6.5.3. Rural Infrastructure Fund

These funds are available to communities whose infrastructure project will result in increased

employment, and/or capital investment and diversification in small communities. These projects

can include improvements to infrastructure. Here too, the criteria can be confusing but there are

many resources to help communities navigate the program.

http://www.floridajobs.org/RIF

6.5.4. Special District Accountability Program

“Counties and municipalities may create special districts to develop and/or maintain various

wastewater and sewer systems.” Creating a special district would enable the authority to raise

money through bond debt for construction and maintenance of the facility, and to charge fees or

tax assessments for repayment of the debt. (Gaskins 2021)

http://www.floridajobs.org/SmallCitiesCDBG

https://floridajobs.org/community-planning-and-development/community-partnerships/regional-rural-development-grant

https://floridajobs.org/community-planning-and-development/community-partnerships/regional-rural-development-grant

http://www.floridajobs.org/RIF


49 | Page

www.FloridaJobs.org/SpecialDistricts

7. CONCLUSIONS

The purpose of this document is to provide homeowners information on wastewater

treatment technologies for centralized and decentralized systems. The technologies for each are

very similar, just operating at different scales. Also important for homeowners is information on

costs and funding opportunities. Costs are very difficult to pin down exactly because there are so

many variables for both centralized and decentralized facilities. But hopefully the ballpark range

estimates provided are useful for context at least.

In the course of developing this report, we learned about some onsite treatment opportunities

that are not currently being used in Florida but may be useful given our special soil conditions.

One of these includes using a UV or chlorine disinfectant in onsite systems. This is a step that

would happen in the tank and would allow for complete treatment in the tank thus eliminating

the need for a drainfield. Discharge could take place on the property without issue (Groover

2021). This is not a treatment process that is used onsite in Florida yet so more research should

be done to make sure it’s viable, but it shows promise.

Another possibility is to incorporate buoyancy options for tanks that may be at risk from

flooding or storm surge (Groover 2021). These can prevent the tank from lifting out of the

ground if soils become saturated, an event that could introduce raw sewage property and

neighborhood.

This report covered a long list of funding opportunities to assist with septic upgrade or septic

to sewer conversion projects. These projects have garnered much attention in recent years,

especially here in Florida. But we also saw that these are expensive projects. While there are

http://www.floridajobs.org/SpecialDistricts


50 | Page

many programs to help cover these costs one that hasn’t been discussed is Property Assessed

Financing. The PACE model (Property Assessed Clean Energy) is one that has been around for

awhile and has been used by homeowners to install solar panels and finance the project through

their property tax bill. In this way the cost for the upgrade is attached to the property not the

individual and the repayment period can be 10 to 20 years. There is some practical sense to this.

First, a septic to sewer upgrade is an upgrade to the property. If the homeowner sells the house

and moves away during the repayment period, the repayment stays with the properties new

owner(s), after all the seller would not dig up the pipe and take it with them. Spreading the

project costs out over a period of time may help some homeowners complete a project that were

not able to secure funds through other sources. These costs could be attached to a utility bill for

smaller monthly payments, instead of the annual property tax bill that may already be a hardship

for some homeowners (Office of Energy Efficiency & Renewable Energy and Energy.gov 2021).

Onsite wastewater treatment systems in low lying coastal areas face multiple risks from

climate change related impacts. These include flooding, storm surge, sea level rise and rising

groundwater levels for example. These impacts could flood drainfields leading to system failure,

raw sewage backing up into homes or being released above ground. As communities plan for

climate change, considering the impacts to septic systems should be included in adaptation and

resiliency plans. This resource provides homeowners information on the technologies of

different wastewater treatment systems, some examples of cost and funding opportunities to help

communities not just plan but pursue projects to reduce the risks to septic systems.


51 | Page

8. REFERENCES

“62-302 : SURFACE WATER QUALITY STANDARDS - Florida Administrative Rules, Law,

Code, Register - FAC, FAR, ERulemaking.” 2020. Florida Administrative Code &

Florida Administrative Register. October 4, 2020.

https://www.flrules.org/gateway/ChapterHome.asp?Chapter=62-302.

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9. TERMS

Aerobic – an oxygenated environment

Anaerobic - an environment without oxygen

Centralized – managed by a central authority

Decentralized – managed at the onsite or local level

Effluent –liquid leaving a wastewater treatment system or component of the system

Influent – liquid entering a wastewater treatment system or a component of the system

10. ABBREVIATIONS

ATU – Advanced Treatment Unit, sometimes also used for Aerobic Treatment Unit


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BOD/CBOD – Biological Oxygen Demand/Carbonaceous Biological Oxygen Demand

CDBG – Community Development Block Grant

EPA – Environmental Protection Agency

FDEO/DEO – Florida Department of Economic Opportunity

FDEP/DEP – Florida Department of Environmental Protection

FDOH/DOH – Florida Department of Health

HUD – Housing and Urban Development

OSTDS – Onsite Treatment and Disposal System

PBTS – Performance Based Treatment System

SBG – Sequencing Batch Reactor

SLR – Sea Level Rise

STEP – Septic Tank Effluent Pumping

TN – Total Nitrogen

TP – Total Phosphorous

TSS – Total Suspended Solids

WWTF – Wastewater Treatment Facility