Innovations and Regulations for Septic Systems for ... System Innovations and...Innovations &...

Eberhard Roeder

11/04/2014

Innovations & Regulations

for Septic Systems

for Environmentally

Sensitive Areas

Winter Seminar, Big Bend Chapter

Florida Water Environment Association

November 04, 2014

To protect, promote and improve the health of all people in Florida through integrated state, county, and community efforts.

Division of Disease Control and Health Protection

Florida Department of Health

Outline

• Regulations

• Inspection

• Treatment

• Innovations

• Florida Onsite Sewage Nitrogen Reduction

Strategies (FOSNRS) Study

(Recent Presentation to Technical Review

and Advisory Panel by Department’s

Contractor)

2

Onsite Inspection Programs

• 381.00651 Periodic evaluation and

assessment of onsite sewage treatment and

disposal systems (2012)

• County or municipality with 1st magnitude

springs can opt out (all did)

• County or municipality without 1st magnitude

springs can opt in (none did)

3

Onsite Inspection Programs

• Must follow statute

• Inspection every five years all systems in area

• May not mandate evaluation at point of sale in a

real estate transaction (repeal existing ordinances)

• May not require soil examination

• Exempt

• Systems with operating permits

• Connection to sewer system is imminent

• Residential dwellings on lot with a ratio of one

bedroom per acre or greater

4

Inspection Programs: “Failure”

• System failure means:

• Discharge of …wastewater onto the ground

surface or into surface water

• Failure of plumbing to discharge properly

• System failure does not mean:

• Drainfield does not meet minimum

separation distance to water table

• Obstruction in a sanitary line or an effluent

screen or filter prevents effluent from flowing

to drainfield

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Treatment

6

http://www.floridahealth.gov/environmental-

health/onsite-

sewage/research/_documents/research-

reports/_documents/keys-nutrient-phase2.pdf

http://www.floridahealth.gov/environmental-

health/onsite-

sewage/research/_documents/research-

reports/_documents/keys-nutrient-phase1.pdf

Onsite Wastewater Nutrient Reduction

Systems (OWNRS) Study

7

OWNRS Results Total Nitrogen

• >70% TN reductions are

achievable

(w/o carbon addition)

• not capable of meeting

Advanced Wastewater

Treatment (AWT)

Standard (3mg/L)

RSF-ABF=Recirc. Sand filter with anoxic biofilter

LBRICK=Septic tank +drip on lined brickchip field

FAS=Bio-Microbics FAST

CFCR=Continous feed cycling reactor

RBC-ABF=rotating biologica contactor with anoxic biofilter 8

1993 study: TN=39 mg/L

Performance-Based Treatment System

(PBTS)

• Designed and certified by a professional engineer in Florida with a background in wastewater engineering

• Achieves a specific and measurable established performance standard of

– biochemical oxygen demand (CBOD5), total suspended solids (TSS),

– total nitrogen (TN), total phosphorus (TP)

– fecal coliform

• Requires operating permit and maintenance agreement with entity authorized by engineer and manufacturer 9

Innovative Systems

• …employs materials, devices, or techniques that are

novel or unique and that have not been successfully

field-tested…

• Permitted as performance-based treatment systems

• Limited number, monitoring protocol

• Entry requirement: test center testing

• 2008 innovative permit for two-stage system (could

be passive), so far, only one installation as part of the

FOSNRS study

11/4/2014 10

Treatment Requirements

Section 381.0065(4)(x), Florida Statutes (2012)

(x) A governmental entity, including a

municipality, county, or statutorily created

commission, may not require an engineer

designed performance-based treatment

system, excluding a passive engineer-designed

performance-based treatment system, before

the completion of the Florida Onsite Sewage

Nitrogen Reduction Strategies Project.

…(grandfather clause)”

11/4/2014 11

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FLORIDA ONSITE SEWAGE

NITROGEN REDUCTION

STRATEGIES (FOSNRS) STUDY:

Overview and Status

Presentation to the FDOH Technical Review and

Advisory Panel (TRAP)

September 25, 2014

by

Damann L. Anderson, P.E.

OTIS

ENVIRONMENTAL

CONSULTANTS

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PROJECT TEAM ACKNOWLEDGEMENTS

OTIS

ENVIRONMENTAL CONSULTANTS

And many support firms and staff!

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Presentation Outline

■ (Nitrogen Impacts to Water Quality) (shortened)

■ Nitrogen reducing OSTDS

■ FOSNRS Background

■ Passive Nitrogen Reduction System (PNRS) Pilot

Studies

■ Passive Nitrogen Reduction System (PNRS): Full

Scale Implementation

■ Overview of Tasks C and D, N Fate & Transport

■ Summary & Questions

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In some watersheds OSTDS nitrogen loading is relatively low (Wakulla Springs 1990-1999)

Atmospheric Deposition

26%

OSTDS 6% WWTPs

40%

Residuals Disposal 15%

Sinking Streams

4%

Livestock 2%

Commercial Fertilizer

7%

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In other watersheds OSTDS nitrogen loading is relatively high (Wekiva Study Area)

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Nitrogen reducing OSTDS

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Nitrogen reducing OSTDS ■ Concerns over nitrogen loading have led to

requirements for OSTDS designed to reduce nitrogen,

typically to 10 mg/L total nitrogen, prior to discharge to

the soil

■ Currently, most are mechanical treatment units utilizing

an activated sludge biological (BNR) process, similar to

a municipal treatment plant

■ Two step process:

1. Aeration to “nitrify” nitrogen compounds to

NO3 (nitrification)

2. Anoxic conditions to “denitrify” NO3 to

nitrogen gas (denitrification)

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Recent evaluation in Florida showed inconsistent results for these performance based treatment (PBTS) systems…

“Of a total of 59 performance based treatment systems (PBTS)

inspected in Wakulla County, 23 (39%) of these systems were not

functioning properly at the time of inspection” Harden et al. (2010)

Properly Functioning Systems Mean TN = 29 + 19 mg N/L

61% 39%

Performance Based Systems Examined in Wakulla County, FL

FunctioningProperly

NOT FunctioningProperly

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FOSNRS Background

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FOSNRS project initiated by Florida

Legislature

■ Laws of Florida, 2008-152, directed FDOH to conduct

a study to further develop more “passive” & cost-

effective nitrogen reduction strategies for OSTDS

■ Initiated the Florida Onsite Sewage Nitrogen

Reduction Strategies (FOSNRS) Project in 2009

■ RFP identified four primary study areas

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Four primary study areas

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Passive Nitrogen Reduction

System (PNRS) Pilot Studies

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What are “passive” nitrogen reduction

systems?

■ Passive nitrogen reduction systems (PNRS) are OSTDS

that reduce effluent N using reactive media for

denitrification and a single liquid pump, if necessary.

■ Two stage process:

● Stage 1: “nitrify” nitrogen compounds to NO3

(nitrification)

● Stage 2: “denitrify” NO3 to nitrogen gas

(denitrification)

nitrification media:

expanded clay

denitrification media:

elemental sulfur

denitrification media:

lignocellulosics

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Two-stage single pass pilot-scale biofilters

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Photo of two-stage single pass biofilter pilot units

Stage 1 Unsaturated Biofilters - Nitrification

Stage 2 Saturated Upflow Biofilters - Denitrification

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 50 100 150 200 250 300 350 400

TN R

ed

uct

ion

Eff

icie

ncy

, %

Experimental Day

Single Pass System

Recirculating System

PNRS pilot-scale test results

Both Systems: Stage 1 Nitrification: Clinoptilolite Biofilter Stage 2 Denitrification: Sulfur Biofilter

~95% TN Reduction

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Single Pass System

Stage 1 Nitrification: Clinoptilolite Biofilter Stage 2 Denitrification: Sulphur Biofilter

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Vertically Stacked In-situ Biofilter Concept

Also investigating in-situ stacked

biofilters

Impermeable Liner

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In situ Stacked Biofilter Construction

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Pilot vertically stacked biofilter system performance

Mean results over 8 sample events, 523 days of operation

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Lessons learned from pilot test

■ Encouraging results from pilot PNRS; several system

configurations capable of > 95% N reduction

■ Sulfate production vs nitrate reduction

■ Highly reactive elemental sulfur media

■ Lignocellulosic retention time issues

■ Recommended evaluation of combination lignocellulosic and elemental sulfur denitrification systems for full-scale treatment units

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Passive Nitrogen Reduction

Systems (PNRS): Full-scale

Implementation

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Task B Overview

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Seven PNRS systems installed

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Hillsborough County PNRS: Tank System with

Recirculation

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Hillsborough County PNRS Location

■ Single family

home

■ 3 bedroom

■ 2 residents

■ Flow of 108 gpd

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PNRS Flow Schematic and Basic Design Criteria

ID HLR Flow

Stage 1 3.0 gal/ft2-d forward flow

108 gpd forward flow 450 gpd total w recycle (3.2:1 recycle ratio R/Q)

Stage 2, lignocellulosic 3.0 gal/ft2-d 108 gpd

Stage 2, sulfur 6.1 gal/ft2-d 108 gpd

L S

Existing STU

NO3

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Stage 1 Recirculating Biofilter Construction

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Stage 2 Denite Biofilter Construction

Perforated distribution pipe

SST drivepoint sampler tree

Clean-out for underdrain pipe

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Completed Two-stage PNRS

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Hillsborough County PNRS Results through Experimental Day 535

TN Reduction Stage 1, 44%

Stage 2b, 95% prior to

STU/drainfield

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Hillsborough County PNRS: Time series of nitrogen data

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Hillsborough County PNRS: Operation and maintenance

■ Average energy consumption of 0.31 kWh/day or 2.7

kWh/1000 gal treated

■ Stage 1 biofilter – no surficial biomat or clogging present

■ Stage 2 biofilter – reactive media shows very little

reduction in volume

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Seminole County PNRS:

Single pass tank system

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Seminole County, FL PNRS Location

■ Single family

home

■ 4 bedroom

■ 5 residents

■ Flow of ~287 gpd

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ID Surface Area HLR

Stage 1 113.2 ft2 2.5 gal/ft2-d

Stage 2a Ligno 36.2 ft2 7.9 gal/ft2-d

Stage 2b Sulfur 18.1 ft2 15.8 gal/ft2-d

Wastewater

from Home

Septic Tank

(Primary Treatment)

Stage 1 Biofilter

(Nitrification)

Stage 2 Biofilter

(Denitrification)

Subsurface

Dispersal

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Seminole County PNRS Preliminary results through Experimental Day 321



STU/drainfield

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Marion County PNRS:

In ground, vertically

stacked biofilter system

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Marion County, FL PNRS

■ Single family

home

■ 2 bedroom

■ 2 residents


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ID Surface Area Design HLR

Stage 1 Sand 375 ft2 0.8 gal/ft2-d

Stage 2 Lignocellulosic 792 ft2

Wastewater

from Home

Septic Tank

(Primary Treatment)

Pump tank

Stage 1 Biofilter (Nitrification)

Stage 2 Biofilter (Denitrification)

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Drip system with reuse

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Seminole County, FL PNRS Location

■ Single family home

■ 5 bedroom (2 residents)


■ Mounded drainfield

■ Myakka and EauGallie

fine sands

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ID Surface Area Design HLR

Stage 1 728 ft2 0.8 gal/ft2-d

Stage 2 32.3 ft2 18 gal/ft2-d

Drip irrigation 615 ft2 0.94 gal/ft2-d

P

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Stage 1 Lined Drip Irrigation

Pipe boot

Gravel Underdrain

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Stage 2 Denite Biofilter Construction

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Seminole County PNRS Preliminary results through Experimental Day 321



STU/drainfield

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Time series of nitrogen data

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Drip Irrigation System

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Subsurface Drip Irrigation Construction

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Task C Overview

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C-HS2 Longwood, FL

B

B’

A

A’

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Task C monitoring – before PNRS installed

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Task C monitoring – after PNRS installed

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Task C monitoring – after PNRS installed

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Task D is evaluating nitrogen fate and

transport scenarios Configuration: trench, equal distribution Soil Type: less permeable sand Loading Rate: 2.67 cm/d (0.65 gpd/ft2) Effluent Nitrogen: 60 mg-N/L as NH4

Depth to Water Table: 60 cm (2 ft)

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Putting it all together…

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Summary & Questions

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FOSNRS Summary

■ Multi-prong project underway to reduce nitrogen from

Florida’s Onsite Sewage Treatment and Disposal

Systems

■ Integrated tasks of:

● Treatment technology evaluation including new passive

systems

● Full-scale field testing of PNRS treatment technologies

● Monitoring of nitrogen fate and transport in subsurface

● Modeling and planning tools to support regulatory decision

making

■ Successful results would allow OSTDS to achieve

nitrogen removal similar to wastewater treatment plants

and play a role in nitrogen reduction in sensitive

watersheds.

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QUESTIONS ?

Damann L. Anderson, P.E., Vice President Josefin E. Hirst, P.E., Senior Principal Engineer Hazen and Sawyer Phone: 813-630-4498 e-mail: [email protected] [email protected]

mailto:[email protected]

mailto:[email protected]

Eberhard Roeder, Ph.D., P.E.

850-245-4250

[email protected]

http://www.floridahealth.gov/environmental

-health/onsite-

sewage/research/index.html

73 To protect, promote and improve the health of all people in Florida through integrated state, county, and community efforts.

Division of Disease Control and Health Protection

Thank you!

Innovations and Regulations for Septic Systems for ... System Innovations and...Innovations &...

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Transcript of Innovations and Regulations for Septic Systems for ... System Innovations and...Innovations &...