RECEIVED

c~

~

r~c~v~

MMH

052002

GLAS

STALL

Ut-

iu..tNOIS

Pollution Control Board

WASHINGTON,

D.C.

MEMBER

WORLD

LAW

GROUP

A GLOBAL

NETWORK

OF

INDEPENDENT

FIRMS

LOCATED

IN

30

COUNTRIES

R02-11

Rulemaking-Water

GARDNE

CHICAGO,

ILLINOIS

60610

(312)

644-3000

FAX:

(312)

644-3381

INTERNET:

gcdIawchgo~gcd.com

WRITER’S

DIRECT

DIAL

NUMBER

SHEILA H. DEELY

(312) 245-8479

sdeely@gcd.com

March

5,

2002

Ms. Dorothy M. Gunn

Clerk

Illinois Pollution Control Board

100 West Randolph St.

Suite 11-500

Chicago, IL

60601

RE:

IN THE MATTER OF:

WATER QUALITY AMENDMENTS TO

35

Ill.

Adm.

Code 302.208(e)-(g),

302.504(a)

302.575(d),

303.444, 309.141(h);

and

PROPOSED

35

Ill. Adm. Code 301.267

301.313, 301.413,

304.120, and 309.157.

Enclosed please find three exhibits

to the written testimony ofMichael Callahan on

behalfofthe Illinois

Association ofWastewater Agencies that were inadvertently omitted from

the filing in the above referenced proceedings.

Verytruly yours,

/IL~L

~

Sheila H. Deely

Enclosures

CHO1/12212127.1

Dear Ms.

Gunn:

)

)

)

)

)

---

Attachment A

---

Nitrification

in

DOD5

test

increases

POTW

noncompliance

JQ~14

C, Hall;

Robert

J.

Foxen

The Clean Water Act retiuires

that

municipal

waste-

water treatment Iheffities

achieve

limitations

based

on

secondary treatment.

The

U. & Envlmnmcntal Protec-

tion Agency

(EPA)

has defined

secondary treatment

as

an effluent containing no

more than

30

mg/I. of 5-day

bloebemicaloxygen

demand (DOD5), and

30 mgfL total

suspended

solids

(TSS),

or

85

removal

of these pot-

lutants, whichever

is more

stringent

Presently,

about

7900

outofa

total

of

15200

municipal treatment plants

have

facilities designed

to

provide secondary treatment

lcvt

EPA estimates

about

20 to

30

of all

scccrndasy

plants have sir

if,r~’nt

violations ofththr HOD, permit

limitations.

Noncompliance may be caused by a variety

of

design

and operational problems. However, a significant ant-

tributing fhctor that

may

account fora large percentage

of the BOO,

violations

involve,

the

BOD~

trsthig

pro-

cedure

it~&i1a

Recent data.

analyses

by

the

Office

of

Waler Program Operation

(OWPO) indicate t1*t niors

than

60?h

of

the

HOD,

violations

may be caused by

nitriheation

in

the

BOY)5 test,

rather

than by

improper

facility design

or

operation.

Revisions to the

biochemical

oxygen

dnmnnd

test procedures

to

inhibit

nifrification

would provide a more accurate measure

•

This paper evalnatri the treatment capabilifics of

nan-

0c1p2d secondary

tmcatwcut facilities and cxaanines

rite

ntent

to

which

nibilication

in

the BOL~5test

may be

contributing

to

compliance

‘ilolations.

First

the thea-

reljcSl

jpa~j~

and origin of the 30.xtg,IL HOD5 stan~iard

are

revj~wed.

Dat.afrom 41) mutsicipal treatment facilities

are

analyzed

to

determine

actual

cnibOststcOns

BOO5

(CHOY),)

treatment

capabilities3

and

to

atirnate

the

amount

of nitrogenous

oxygen demand

(NOD) exerted

in the

BOD,

test. This information is

then

used

to

e~fimatt

the overali

extent

to

which

altrification occurring in the

BOD3

test çontribntcs to

violations of seccedary pcrnsIt

limitations.

STATEMENT

OF

PROBLEM

-

Populations

of

purifying bacteria in untreated wasto-

water are usually too small

to

impact HOD3test resuils.

Therefore,

the

BOY), test typicallymeasures only CEOD,

in

untreated

wastewatcra.

Howc-Mcr,

the impact

of ni-

tril5ing

bacteria

on

HOD,

teste

of

biologically

treated

wastewatcxs has

long

been

recognized,3

becanic

sub-

stantial

populations

of

nitrifying

bacteria

may

exist

in

the

auents.

Sawyer’ stairs that effluents from secOnd-

ary

facihhics

Thiten

contain populations

of

nitrifying

organisms

sufficient

to

utilize

a

si~nzficwzt

(ezuphasis-

added)

amount

of

oxygen during

the regular

5-day in-

cubationperiod. It is important to

know

the amount

of

residual carbonaceous BOY)in suck casts in order to be

able

to

measure plant efficiency.”

Interpreting

the

results of the standard BODç

1St for

secondary effluents

is

further complicated

becau3c pop-

ulations ofpitrifjáng bacteria vary

signifleantly depending

on

environmental conditions.

For

example, during cold

weather

it is unlikely

that

large populations of aitrifying

bacteria

would

be present

in an effluent

frot

a

conven-

tionally designed secondary

treatment

plant

because the

low wat~ tempezatores

minimize

their

growth

‘ate.

However,

during

Warm

weather this

same

facliity~rn

develop pop~ilatloasof

nitrifying hactaia that arecapable

of

exerting significantamounts

of

NOD

in the

BOY), test.

Because significantpopulations

of

nitrifyingbacteria

may

be

present in a &ciflty

during

warm weather conditions,

but absent

at other times,

HOD,

results measured undir

difitrent

temperatureconditions

catinotbe comparedwith

any certainty of ucifortu tear

conditions.

The

usefulness

of

BOY)5 data that

include

varying degrv’~

of NOD- in

addition,

to

CBOD5

is

ciuestionable, therefore the

15th

edition

of

“Statidard

Methods”

recommends inhibiting

nitrogenous

oxidation

for

all

mnaples

from

secondary ef-

Cuents

or polluted

waters.5

December

1983

1461

---

Mall

& Foxen

The typca of’

secondary

facilities most

conducive

to

-

development of

nirilfying bacteria an~

tmderioaded

or

overdrzigrs-ud activated

sludge

facilities

and most tdck-

ling

filters.

During warm

weather, activated sludge 6-

duties with

lower loading

tates may provide

sufficient

mean cell residence time (MCR.T) to develop a signifl-

cant

population

of

nitrifying bacteria. This could occur

irnerxnittenriyor continuously, depending on

the. char-

acterisucs ofa particular facility.

Trickling filters are particularly

conducive to

growth

of nitz-i5ing bacteria during waz~weather beana.se the

filter media provides an ideal

base

for nitrifler growth-

staje~that

nitrification

in

the

DOD,

test

is

a

particularly signiflesnt problem

for

“trickling filter plant

where ainification

takes

place

rapidy

as

compared to

effluents

from

conventional

high-rate

activated dwigt

plants ~terc

nitrificatigu proceeds mote

slowly~Thus,

trickling filter efilueiats may contain

higher couceatra-

tiozis

of nitritjring

bacteria than

effluents

front

conven-.

tional

activated sludge facilities.

ORIGUi

AND

INTENT

OF

THE

DOD5

SECONDARY

TREATMENT

STAI’WARD

Although signthcantnitdflcation

can ccur

in

theDOD,

teat

for

secondary

effluents,

much

debate

ccnters

on

whetherthe 30-milL BOO5 standard, as defined by EPA,

was

lnzendedw

include only carbonaceous

oxidation, or

also any Stregcnous oaidation that might be exerted in

theDOD5 test. This distinction iscritical, because it would

not

be ai,propriatc

to

change the current BOD.~test re-

quirerneat

to

a

COD,

tcst

without

a

corresponding

change in the effluent standard if the

original BOY)5 stan-

dard w~intenclerl

to include

both

COD,

and

NOD.

Onthe other band, ifthe Original 30-ma/L HOD5~andath

W3~

intended

to

include

only

CEOD,.,

the

DOD,

teat

-

could

be modified to measure only

C30D5,without

any

corrawctading change

En the effluent slnndar&

The position that BOY), was intended to.include bath

CEO),

and NOt) is basically as follows:

-

The

30-tngjL BUD5 standard wasbased on an

era-

untion

of

EQ)5

effluent

quality

from a

represerz-

lativepopulation

ofsecondary treatment facililius.

~

the effluents from

these tèeatrnent

plants

would presumably

contain

“typical”

amount

of

NOD5,,

the 30-mg/L

BOO,

standard

based on this

sample populates

also account forthis same

“n’m

lest”

amount

of

NOD.

Use of theCOD,

test with-

-

out

a corresponding

change in the standard would

essentially constitute.a

relaxation ofstandards ‘that

couIØ

in

turn, degrade water quality.

Although anevaluation ofse

darytresintent thcll,i’des

may

indicate

that

30

mg/L

ROD,

is a teasonable

see-

ondary effluentstandard, review

of

EPA documents lead-

ing to the establishment ofthe secondarytreatment stan-

dard indicate thatthe figure of30 mg~twasnot originally

derived through an analysis of’ effluent data. fli~

30-mg/

L SOD, standard wasbased primarily

on an 85

BOb,

removal

requirement

contained in a suaerscdixl regula-

ton.tb

Development documents concentin; theproposed

~

ondat-y treatment regulation (40 CFR Part 133) statethat

EPA

found

“the level

of

effluent

quality

proposed

is

roughly

equivalent

to

the

former

18

CFR

60

t.25

re-S

qeirement

of

85

HOt)5

removaL”7 Other

docunsents

also

indicate

that the

3C1-mg/L ihutintion

was derived

frc,mn

plant ethciancy based on apcceaiaee removal (that

is,~fl

removal assumingatypicalinfluenr

SQTh of 200

mg/L), and wasnot originally based on an.empirical anal-

ysis of effluent data.’ Asdiscussed

previously, the

HOD,

test

for

untreated

wastewainr typically

measures

only

COD5

because

niirif~.-ingpopulations

art

usually

too

cain

to amen any appreciable oxygen demand in the fast

5 days. Because the inftucnt

test typically inenstifes

only

CR01),,

thceffluenttest should also measure only CROP,

to

accurately calculate

percent

removaL

Therefore, the

30-.mgfL effluent standard

should include

only COD,.

Aftermaking thepreliminary detcnnination that

S5

rcmao-ral of HOD5 was an appropriate

measure

of

effi-

ciency for a well-operated

srtondary treatment

facility’

and that

30 rngJL was

roughly its

equivalent

(assuming

a 200 mg/L intluent

concentration),

EPA

completcd a

study of

secondary treatmentfacilities to verify this

find-

ing.

The

unpublished

smdy’°

evaluated

efflucut

data

from

33

secondary activated

sludge and triciding filter

facilitiesthat

were “well operated” and ‘operated at

er

near

design

flow.”

However,

these

selection

eritoria

tended

to minimize

the probability

ofnifrifrattioti

oc-

cnn-hagin

the

nOD, test. The

amount of

NOD,

forthese

plarr~should be significantly lower than

if

a truly

rep-

rsen’iative sample population (thatis,

including under-

loaded

plants)

had

been

selected.

Secondary

facilities

“at or

near design flow” are

less

likely to have sufficient

MCRT

for

signiflcazxt numbers

of

nitrifters

to

develop

compared

to

facilities

that

operate below

their design

flows. Therefore, effluents from the facilitiesin the sam-

ple

population would not er.hibit

NOfl~

concentrations

rcpt-raentative

of all

secopdary

facilities.

This

may be

true

for newer

facilities that are well below their design

flow and thus more lilcelyto have adequate

MCRTs

for

significant nitrifler

development.

The

final

EPA

document defining best practicable waste

treatniefit technology (BPW~~)

for mwnctpal diechargers

published

in

October

1975”

ft’rther clarifies the intent

of the HOD, test and the secondary standard.. This dcc-

‘omont

states that

“the

BUD3

test

essentially

measures

the oxygen

demand

of

only the carbonacona

organic

material

in

t~xenstewater

~ffltieut”

The document also

presents a table summarizing the pofltrtant

removal ca-

1462

Journal

WPCF, Volume

35,

Number

12

t.

C

S

fl.

I

---

Wastewatcr Analysis

Tblo

1—Typical

miens

of

ultimate

orygen

demand

-

Carte-

Nttrog-

treatment

type

nolan

qno~

Tot.s

Rema,tal

~aw

•

300

KO

400

0

p~j~~’a~y

3ccuar~ay

Q*jthate)

180

96

45

a,

275

135

31

59

Secoflor (wXnven1vna~

(wintaj

23

90

113

74

~wpe()

23

23

46

98

TWOttagn

rt,tec

Mvanceo vesaetrearnent

23

9

23

¶2

46

20

83

-

95

R~pdntqçt

tr~yy~

“Afternativa

Wasta Mngernent

TecJ—ulques tnt

sect

Practicable Waru~

Tr~trnent7

EPA-co/g.75.otS.

16 ~Oa

1975)-

pabilitia ofsecondary treatment ~iqi~rt

(Table 1). This

table stows that secondary treatment as

dthned

by EPA

(that is~high razesetoudary;

conventional socondary ac-

tually

provides seasonal nirrification) reduces

CEOD vi-

timata

from

300 to

45

mg/I-.

This lenl~

of removaL is

equivalent

to

the

35

rethcval

requirement

discussed

previously.

Using the CBOD

ultimate/CHaD5

ra~oot’

1,5, sa recomurcridcd in

the

document, a BQJD5 standard

of

30

itigjL found in

the secondary

regulation (40 CFR

Fiat 133) can be calczilatei The document also indicates

that scasorial nitification

is not to be established

assec-

ondary treatment. This reiterated theagency position that

the

oxygen demand

from ammonia

would

not

bt con-

trolled

through secondary treatment

and

that EPA in-

tended secondary technology only to bay

the

capability

to remove carbonacaou~

xnatenaV~

Thus, it would have

been inconsistent with thisintent to acta secondary stan-

dazd

that included

nitrogenous

BUD,

in addItion to

car-

bonaceous

BUD,. It

seems that EFA intended to regolate

only CBOD, through secondary treatment

A

final point of concern

raised by athocates of the

existing

BOD~testing ptgcadum

is

the potential

water

quality

impact of

changing

the SOD,

test t~

include

onlyb COD,.

Advocates

of the

HOD,

standard

state

that

NOD

should be ow,unted

for in

tile BO~,

test

because

NOD will

~xefl

an

oxygen

demand

in the

i-c-

calving water

equal to the oxygen

demand in

the DOD5

teat.

Thus,

water quality wonl4 be adversely impacted

lithe

test

measured

onLy CR01),, t~ase

the impacts

of

NO!) would

not b.c considered.

Theflullacy

of

this ~osition

is that the amount

and rate

of oxidation

of

ammo-cia

occurring

in

the

BOD~tact

bottle

usually

differ from

that

in

the receiving water. if

an effluent with

a. significant NOD were discharged into

a

relatively deep

river with a sandy

bottom,

it i~t

uniiksly

that any nittifleation would occurbecause ofthe physical

characteristics ofthe receiving stream.’

Similai examples

could occur in’~any

situation

where

an

eWucnt initially

containing nitrifying bacteria is

d

argod

into

a stream

where

the

pH,

temtnnzture,

chemicaL or

physical prop-

erties were not conducive to the growth ofnitrifying bce-

tcria. On the other hand,

in a stream

or river there

may

be substantial thtdulcation oàurring

eventhough theplant

aueat

dischaurgniinter the receiving water

maSt not ex-

hibit nitification

in the BOD~

t~

Thus.

whether

or not

nitrifleation occurs

in

the receiv~gwater isindependent

from

the oceuffence

of

niulfication

in

the

test.

In

any

event, the potential efi~ctrof effluent

asamonla and

the

posetbleneedfor nitxiflcaiion facilitiesshould be evaluated

in

water quality

ntodeling analyses because these areas

of concern

are

not

addressed

in

the

technology-based

standard.

THEORETICAL

IMPACT

OF

NITROGENOUS

OXIDATION

The

possible problems with mcasnringtotal

BOlD,axe

illushatcd in the following

tssample. Table 2 shows the

effluent quality for two hypothetical treatment faculties,

one

providing secondary treatment with

no nitrffiers

in

the

effluent and the otherjust bc~inningto ziltrify. The

-

effluent from the secon4ary acit*tj~contains 30

mg/I,.

COD,

and 20

mg/I,

ammouia,

and ultimate

oxygen”,

demand

(liOn)

of

136

tnE/L.

Because

there arc few

nutrificre present in effluent from this facility, the DOD5

tat would indicate air

eWutent ROD, of 30

ns,gjt (iden-

tical to COD5).

Table 2

also shows that the facility

in

the-incipient

nitrification

stage provides slightly better treatment, and

produces an

effluent

with

about 25

wg/t

CEOD,.

18

mg/I,

ammonia, and

120 mgfL

UOD.

However; in

this

case, because nitrifleis arepresent

in

the efflueni, an-NOD

of56 ing/I, might be exerted

in the DOD,

test. Thewould

yield

a

DOD,

of

81

mgJL—neatly

three

thrice

greatun-

than that

of

the secondary flucilit

that discharged poorer

tabte

2—Theoreticat impact

of

nivogenuzis

oxidatto

n on

SOi’~

turn reautrs

type

Operating eandlS~ne

-

CflQD~

-

POt,

UoOw

NOO

SOD,

Secordaiy

Seeaeck’ayfw.oiplgnt

,

nlt,lfieslion

No nlrflfiers

Wem

‘netter,

bemow design

flow.

some nielSen

~ra~ank

-

•

513

25

20

16

136

120

13

56

30

81

•All

-esiuee

~‘

molt—

~UCD:act

1.5

CSOCw 4

457

M-?~.

December

1983

1463

---

Hall

& Foxen

quality

effluent.

ALthough these estimates are

only illus-

trative, they do

underscore

the rere

compliance prob-

lem$

as a

result of

nifrilicatiort

1St

the

ROD,

test. Tho

following

sections present

and

anai~e

available side—by-

side BOD1/CROD,

data

and show the

effects

of nitrifi-

cation

on the ROD5

test.

These data provide a basis for

cstinictixrg

the

tration-adde

impact

of

this

problem

on

treatment

plant

compliance.

-

EVALUATION

OF

BOD5

ANTI)

CBOfl~

DATA

-

Data

descriptia

Data

were obtained

from municipal

treatment

plant

records at

40

facilIties- where

side-by-

side BOlD, and COD~

testswere rum

It

is

bdievcd

that

the data reprEsent a

large percentage

of

the facilities in

the U. S.

with available thde-by-.sidc BODS/CBOD, data.

Although a few Ikdilhlies submitted data

to

EPA

specif-

icallybecause

of

nitrification

problemsin the DOD5

test

the

~rpjple

covetsa wide range

offadfttty sizes. locations,

and

design coudilions.

The dataare

believetho represent

nationwi4~conditions.

A

list of

the

data for each

facility appears in

Tables 3a

and

ab,and a

$nmrflai-y

ofthe datais

presented in

Table

4.

The effluent cotieentations

listed In

bath

w,ias

art

the

average warm

wtathet e~zcntqoalit)- (sampled be-

twecn May

and

October). except

wheat othcri~tcspec-

ified.. The facilities have 15cm

ç1a~sifi~4

as

either nitrifi-

cation

or

secondary

treatment pnccz~cs.The facilities

listed as nitrification plants were either4esigned

to nitx-ify

or

exhibited at least

75

ammonia

reaiovai during

the

sampling periocL Thu theilitics listed as secondary etb

ited-eithcr partial

(10

to

60)

or

miaimal

ammonia

re-

movaL

The predominant

biological

-treatment process is ac-

tivated sludge,

though data from several trickling filters

and

combination trickling

filter/activated

sludge plants

were

also

obraine~tThe

facilities ranged

in

size from

73.9

to

52596

tIe (1.8

‘to

1

200 mcd).

Most

ofthe plants

were operating below their

design flow capacity.

Njtrfficajjoe

was

inhibited

with

2—chioro-6

(trichlo-

rometityl)

pyridine

(TCMLP).

Investigations

by Young’

indicate

that

TCMP

does

nor

inhibit

oxidation

of car-

bonaceous material

at rceortriracade4 dosages,5 and that

when

nitriliers

arc

not

-

present,

DOD,

tests

with

and

without TCMP

are

equivalent

-

Data analysis. For nitrification facilities, datapresented

in

Table

4

show that on

the average

NOD accounts

for

66)11,

of

the HOD5.

The NOD

ranges

frame

4~te,

86

of

the ROD,.

Effluent

OOD~in

these

facilities averaged

about

4

mg/L,

whereas the DOD5

averaged

about

t3

-

-

For

secondary facilities, data preseated in

Table

4

show

that

NOD

comprised about

52

ofthe

B0D1

The average

DOD, was

23

mng/t. whereas

the averageCBOD,

was

15

rng/L-

There

is

greater variability

in the

percentage of

NOD exertion for secondary slants than

for nitrificatiors

facilities,

with

the percentage ranging

from

24 to

79.

Astalytis

Of

cold

westher

effluent

data

(not

included

in

this

report)

indicated,

on

the

average,

significantly

less

NOD exerted in

the DOD, ‘test, as would

be expected.

Thu

degree

of NOD exerted in

any DOD,

test is

psi-

sadly a

junction

of two parameters:

the

initial

concen-

tration

of

nitrifying bacteria and the aveiiable

ammonia.

In

nitrified

effluents

the NOD would

be limited by the

available ammonia, because suilitheunbact~ia~e

already

present

in

the

sample

for ammonia

oxidation to

begin

irntnediatr.Iy.

Thua,

any

maidnal

ammonia

çnruthxding that

Table 3—Comparison of

summertime coops ana

BoOs

e

nit-tent

date—n

itritioa-tion

facihties.s

new

‘

BO0~

t8OD~

YSS

MOO,,

NM,

-

-

Name

~S1SU4~

Pctign

F?~un

lmgIL)

(rng/L)

(mg/k)

3

(rpajL)

Cbicago (YC),

fl.

3*3

333.0

AS

tO

3.0

7.0

-

a,?

Citago,

(WSW). itt.

at~

500.0

AS

70

40

7C~

4~3

fl5

E.

.

MasS.

I!.

rute-teta

Mn

7

18.4

7

-

-

124

AS

AS

25.0

itO

t8.O

7.0

18.0

20.0

47

57

tO ~W)

2.0

Ft.

Co~rc.

Ct.

7

8.0

aS

18.8

2.3

—

80

ts

Grand tslaruct. Nebr.

6

7-0

eS

SOC

SO

—

75

4-0

Lawrence,

Scare.

Marlborough.

Mass.

6

no

—

5-a

s5

t,5-pu,i,s

~.o

—

5.4

5-4

70

5-4

71

—

5-0

(W)

0.5

rtltsftera,

MaSS.

10

17.0

TF-AS

-

—

ac

at

—

04

Wastinpron.

fl.C.

309

aino

AS

iaa

a&0

-tao

67

as

W,

Contra Costa,

CaNt.

--

-

10

-

-

ias

-was

as.o

s.c

~.0

86

1t0(W)

• Less thw 80t~l+4~removal.

(WI

—

Winter-average.

AS

=

ActtvstS

~idoe.

TF

-

TckSdhj flts’.

Phaichemieal Sdit~n

TP

ren’cv&.

Flit

a

1464

Journal

WPCF,

Volume

55, Number

U

---

added

to the dilution

water

used

in test)

would

likely be

otdiaetj. dwinz t3se flit

5 days

offlat test

Data inTableS sMw itively

little

ammonia available

in the nirrifled effluen~

(0.5 to 5.0

mgfL

ácluding

am-

mc’ttia added to the dilution waxer). Jtafiluctzi~

ammonia

levels weit

incxtased

without

a

~wcaiponding

deaeese

in

niuifints,

si~xiiflcantlymore NOD wotdd be exerted

In the BOD,

test

and could cause txnnplianbe problems

Table

£—Sulrnmnaryat

lndiwiduat plant dsta.

N

ai’

sen.

casx~1

two

its

Tip.

fit..

çmg~tj

(maJL)

()

twoS)

-

II)

1!

7-a?)

4

(26-703

30-

28

(11-C3)

13(5-40)

SG (0.66)

62

(24-79)

9 (5-a)

18 (5w)

.

Erlkn,t

valuesaled as e.aaq

(‘area).

-

The problem

of

increasing ammonia levels

withoax acor-

responding

decrease iii

nitrirying baetcth p~puladouis

-

reprEsented by

West Contra Costa.a

seasonal nttriflcation

facility. The

effluent data

presented

Table

3 were taken

a1~the

ftcility

~sas

no

longtt

operating in

tue liii!

itti-

trification mode.

Effluent

ammonia

increased

to

11

tug!

I.., and resulted

In average

BOD,

uatues

of

35

mgTL (a

secondary standard violation).

CBOD5

remained low,at

only

S

mg/L. Although

the facility

does

not

bave to

re-

move

ammonia all

year based

on

its permit,

ainnionia

removal would be needbl

to easing

compliance

with the

secondary

treatment

standard

as a result

of

the impact

of ninifring

bacteria.

For

aecondaxy

facilities,

the degree of

nitrification

in

the BOD~çtntprinisrily depends

on

the

initial niu±ñet

population

rather than the available

ararnonia

Seause

nitrifying

bacteria regenerate

slowly,

the

low~

MCE.T of

a

typical secondary

facility

(3 to

6

days)

may

~uze

a

-i

I

~-1~

I

Table

4—Campatison

of

nimniefllmg

ceco,

end

SCDg

efituant

data—escandary

tacrntles.

fln~

—

—

Manic

Existing

gOo~,

flexign

-

Pines

(mg/i.)

CSOO.

(nig/L)

T~

(..ig/t.)

NoD1

(5.)

Nt-f,,

(‘nejt..)

Wastewater

Analysis

Aflofl, Otto

56.0

76.0

AS

36.0

15.0

—

60

7

.tibuquerque. N, Ma

37.0

37.0

ThAS

35.0

15,0

10

57

¶5

ElueLalce.Mnn.

14.0

20.0

A5

—

70

10

—

—

ChasM.

~

—

—

AS

17.0

i(~g)

‘p

29

10

Ortega. (CZ4L~.lit.

~.0

220.0

43

25-1)

7.0

3

72

5

Cisarwatatffia

—

—.

AS

31.0

i2.O

—

61

—

Ookndn 3pth~e.

Cdt.

20.0

30.0

ss

25.0

to

i~

64

14

Ccrmnls,Ore.

ac

tv

IF-AS

4.3

25

5

31)

Cctbgcl3ruva

Mien

1.9

as

AS

56.0

25.0

30

54

16

Outuque.twt

iO.0

i~o

50

13

16

.

57

—

0unMn~.

Ore,

6.0

2Q0

AS-PtloeFltr

12

3

5

76

15

a

Detest,

Caner.

3.0

3.5

7$

03

40

66

Sel

19

eJ4wtfoea, Coon.

7_a

t0.a

AS

-19

7

S

63

-

—

En’porfe.fa~.

—

TF

irE

22

fl

—

FOresThlIe, Coon.

3.2

5.0

17

3~3

22

-

37

33

12

I4atfoed.

Coin.

44.0

00.0

AS

lB

9

1~

54~

—

Hastlngs.tSn.

1.2

iS

see

—

15

-tO

—

32

Mlwadcee, Wig.

200.0

200.0

A5.Phos

21

9

31

57

10 ~~‘J

MAdsen, Wig.

35.0

SQ.O

AS

58

12

19

54

Medlcrd,Cre

9.5

lao

ma

It

5

9

55

—

M~rneaps~,

Mica.

300.Q

250.0

AS

20

14

23

30

6

Oregon City, On.

4.5

10.0

*5

iT

12

8

29

—

Poibnc.

MG.

Itt

15.0

.48

26

4

20

00

—

Fo.ifand. Ore.

5.3

t3

AS

115

10

12

79

14

lIens.

Nay,

no

20.0

AS

ac

to

17

50

12

flacw

Hut, Corn.

4.3

7.5

AS

23

S

in

61

—

Seattle.

Wash.

37.0

—

AS

12

8

10

33

‘6

~eca,

t’&~.

-

tao

ao

~s

-

V

15

19

53

22

Etllweter.M$n

2.0

3.0

AS

22

9

11

57

14

tipper~aatratcne.MaSs

30.0

57.0

a$

iS

5

12

74

iS

•Lest) than

50

Mt

rernovat.

1W)

Winter a’.-erege.

AS

—

Aethratetsfud1)e.

=

Tztcldng

Ftltef.

Pt-ice

=

CheeSes *cfliton

TP reeaovW.

Ftw

Decamber

1983

1465

---

wasnour

or

wide

fluctuation

In the nitrifviag

population.

As

a

rcsul;

the

initial

Population

of

nlrrifying

bactcria

Ir

In

the test

ssmple may

-vary cétisidseably and

may

not

bç

sedicteirt

tQ

affect

the test xegcjltsimillilae population

-jji

hcrSses.

Stgni6carn nitrificasion, lilt

ocriirs at an, may

be dekiyed

until the IS

days

ot’ the

test

so -that only a

small jiercenmgc

of

the

available ammonia is oxidized.

A

study an the

effects of fluctuating MC~T

on

NOD5

was conducted at to

Colorado

Sfrings

facility

by

Cal-

laway

and

Young.”

Tbç

study verified that reducing xii-

irifying

population thiough

decreased MCRT results

in

‘1

-

losNOD, eaertion

in

the SOD, test.

-

Although

effluent

ammonia

dati

~cxt

tot

always

‘1-

I

availablefort

secondrytheililies, discussions with plant

speStors

Indiested that

waz’y plants

were

partially ni-

j~.

1

th4thig (about

IOta 60

ammonia removal). Other plants

did

not

eXhibit

any

S.TnQnIa

rerdovaL ~seh

a facility

is

~a

lay nitdl~ing.

a sul

den; nftdMxrg

population is

pTCa&ZC

to significantly

inspect

tb&SOD5 test.

However,.

eyed

facilalets where ttinlftcatjon

is

not

occurring

may

have

sufficient

nitr-iflers

-to impact

BOD) results

ir

the

acnky is in the

incipient nitrilimdon

stag0~

(Sac Alber-

quehquc N.

Mcx case

study.)

Incipient

ultrification

(a’

duties

lxzye

loading ratesand

MCaTs

that permit nhtrilier

po&lulatkmzto be

SnNithe4 however, the

trention

time

in

~

lioiegial

~

~

a

~0w

hI

snot ad

equate for detectable anunozzia reduction. During the

S

daYsofihteSODa test,

the seed nitrifying population has

sufficient time to Increase

and begin ammonia

oxidation.

- -

Similady,

seasonally

a~olea-

wastavater teniperetures

it-

dccc

plant-seale ninificadon.

but fuotbation

at2i)tM

‘the

test quickly

activates the nitril~rixig

population.

Theresults &oxn thi$

~Jn

yagr~witi

a similar

swvey

conducted

in

West-C’ermany

~y

Daxuield)’ Typically,

SOD,

Inst result for both Trickling

mte~

ann activated

I.

siw~plants in

that study were si~iEcanflyhigher than

CR0),

test results.

The amount

of’NOD exertS

in

the

50D5 testranged from greatecthan 60

(ccfacilitieswith

high

MCRTs

to abotat2056 fbrfacilities withlow

MCR.Ts.

To

prevent

znisleading

SOD~’iestresults caused

by ni-

trification-in the

t~

West Cen~any-nowusesthe CR005

test

The following case studies

illustrate

how the BOO,

test

can

provide

misleading

and

contradictory

infor-

mation on plant opcairdoa

-

Qrsse studies:

Fort

Collins,

Cotu.,

and

Albn~uer-aue,

N.

Max. Data

from

Fort.Cofllns,

Cola;

arc presented in

?lgures

Ia, lb. and Ic.Figuz~

Ia

and

lb

indkatst that

there

werelbw ninuffrigbaaöuia in

the plantbetre ApriZ

~

byequal

BOlD,

and

tBODs

test resent and

-

by high effluent ammonia conctntrations.

lxi April.

the

addition

ofone activated

sludge

unit incrrased

the

MCRT

and the plant began titri~ng.

The Figures

Ia

and

lb

show that the monthly average CR005

decreased

from

about

18 totat

S ingfL

and ammonia decreased from

about l~to

3

mg/I..

Xiowcver,

the

EODfr

test results

n

Ti

cone.

J

~

N

A

a

.r-JC4r~!c

N

0

ii

-

41fliQNI~

-

-

S

-

-

-

,

~“~‘—r~

1w

100

~

a

~-4--J-4--’-----------

$

P

UT

A

a

£

7

S

S

0

N

0

~y:~:~:::

Figure

1—Fan

Coffins,

Colorado:

A—.cfthteflt

DOD,

arid

CDOD5 B—effluent smunoalar aM

Q—cfliueat ultimate

ax-

flen

d*-rtu’q4.

(Figure

Ia) did

001

reflect

the signIficant

improvement

in

effluent

UOD (rzgure

Ic)

because increased ammonia

oxidation

vm~

occurring

In

the

test. Zn

terma

of SOb5.

the additional

3cttvated sludge

unit

seemed

to

provide

little if any

iniprovetnen;

although

efilu nt

UOD

de-

creased by abort 80,

CBOD5 and SOD,

efiiuent data ftwn Albuq~rqne.

N.MeL.are

shown in Piguro2. Thedata forearlyMarch

indicated that few

nitrifinre

were

present at

this time..

CR01), and

nob3

values were

rou~bly

equal during

this

period(CBOD, ranging

2(1 to

25

mug/L; SOD,

ranging

25

-it

30

nigJL).

In

curly May,

CROP,

decreased

to

about

10

to

15

mg/I.,

but

flOD,

test results increased

to

between 40

and 90 nrgfL. The

inflated

501)5

values

occurred avon

though

e~izentdata did not indicate any

significant decrease in

ammonia

concentrations

to in-

dicate increased stifler

populations-

This

verifies thai.

even though

populations

of

ninriflers may not

be sui5-

clear to produce plant-scaie nitrification, they

can

still

significantly increase ROD5 test,results. The wide swings

in

the

SOD,

test results also Lilustrate the problem of

using the

ROD5 test to

measure treatment c~thcncyfor

1466

Journal WPCF, Volunic

55,

Number

12

---

0

Wasteâiater AnalyS

Figure2—FInal effluent BOD, and CBOi)c(tng/L) Albuquer-

que, NewMexico.

facilities operating

in

the incipient

nitrificatibn

stage.

Because of varying amounts of nittifying bacteria,

sig-

nificant day-to4ay

fluctuations

ocarr in

the degree of

agunonia

oxidIzed

during

the test

In such casc~,the

HOD5 test can not accurately

characteriae plant pcrfor-

mance and operation.

ESTIMATE

OF

DOD5

ViOLATiONS

CAUSED

BY

NrflUPIC4.TION-

NATIONAL

1MPA~

Given rhosignificant effect that nitxi54r~bacteria may

have on BODE trot results, it is apparent that someBOD~

noncompliance may result solely from NOD

exerdota.

Only 7 ofthe 40 plant

surveyed were out ofeonspljancc

wIth the 30-mg/I. ROD,

slandand during the sampling

period.

Of

these seven plants, only East Bristol would.

have beenout ofcompliance with the 30-mgtt. standard

eve-n If the CEOD,

test bad

been

used.

Although

this

sample is small, these findings

suggest that a significant

perwenta~cof BOO,

compliance

problems may

be

dun

to

nitrificatlon

in

the

test.

and

not

due

to

poor plant

perthrmajme,

-

Because than are relatively few Facilities for which

thie-

by-side BODilCBODs

data.

art

avafhthtc,

the tatlonal

significance ett.bis problem Lad to

be estimated by an-

aI~’zing

available data. to

identify 9ndksto&

ofniftifi-

‘cation in the ROD5 test.

From the

available data

it ~

observed that in

nearly all. cases where significantnitri-

Scation otrtrrrnj in the

B0D~

test.

SOD,

concentrations

were grester

than

TSS concentrations (Tables Sn and

4).

Ineverycasebutone. CR01)5

-was

less~ktn ThS~rcgixdless

of the

degree

of

nitriftastion .occuthng. This

point is

11-

Jusrzated hyP~ure3,wfiithplotstherelationsbipbetweert

CROP, and TSS for the

40 facIlities sampled.

Figure 3

shows that CROD,

was typically

60

to

85

of the TSS

value. Analysis of

wintec

effluent TSS

and

CBOD,

data

(not included

in this report) also

indicated that

CR01),

values are typically

less

than

TSS

values,

when

‘ISS

is

above 20 ing/L. A HOD5

value

greater than the TSS value

would

be

a good

indicator

of significant

nitrifleatton

in

the 301)3 t~.

The empixtal

relationship between CBOD3 and TSS

was -used as a basis for

csliln3ting

the

number

of cases

where noncompliance was caused by

thtrlflcatloa in the

BOD,

restS It

~

assumed

irs

these

estimates

that ci-

trtháadon wq~

tile cause ofnoncompliancc ifDOD5

con-

centration was gitter

than

3(1 rngJL

but

the TSS con-

centurion was less trn

30 mg/fl

Because the data in-

dicate flit CR01),

is

typically about

64) to

35

of

die

TSS value,

it

is

conservative

to assume that

nitrification

is responsibleonlywhen BQQ,

eacect

TSS.

-

fluent

ruonstonug data flora 325 secondarytreatment

ibthlides

in

New York

Mate

were

~s~ed

to

estimate the

national extent of ROD5 test violations caused

by

nitci-

ficntmon. The sample

included.all majorcategories ofIt-

logical treatment processes

(Table 6). Becauseoft

rim

of

the s~xnplc

and the variety of facility types, a

ional

sample is not

likely to produce significantly diBluçnt re-

st

-

The New York data show that

99

ofthe

325 fiwilities

were

in

violation

of their

30-mg/i

SOD5

permit

to-

qufronrent duringthe period

of

recor& However, acom-

parison of BOD~and TSS data revealed that

in ebnost

60

of

thesecasesTSS was less than

30

tng/L. Therefore,

based

on,

available CBQ1), data indicating that

COD5

should

be less than

TS5. It

was concluded

that about

60

of the 301)5 permit

violations may be caused by

nitrificarion

in die test,

rather Than by improper facility

design or

operation,

A detailed breakdown

of the

number

of

UODg

viola-

lions

caused

by

nitrification

for

different

categories

of

facilitiesappears

in tableS. This

table shows thattrickling

a

;~T’4J

an.

,a~5y

—.

.

—

1,7; 1

at.

caog~

~0

so

20

\~I,7’

,,~

sacs

/

en

1.2:1

,5...—Te~

gaoa~

1;t

Cit

I

IL

11.

‘U

10

20

EI’I’LUENT

CzQo5 fsnØI)

Flute 3—Relationship

between

CBOD5

sad

TSS.

December

1983

---

flhtth

acre

most

often

cited for

noncanspbance

(61

of

133

planb

CM

tot

meet 30 rugfL ROD,).

However,

this

table

shows

that

40

c(

the

61

violations,

or

65,

were

probably

the

result ofNOD exertiOn in

thetest

Previous

discussion

indicates that a.ttacthed growth plants

provide

an excellent environment forgrowth otn*trSfl~tgbacteria.

BOiD, test

results for

thi5

type

of procass may

well

be

significantly inflated

as a. result of ammonia

oxidation.

The

data in TableS

show that about 60

of

DOD,

com-

pliance

violations ftir the acUvated sludge facilities may

be

cars-ted

by NOD

acrilon.

-

•

Assumng

that these

estimates

art

represenialiva

of

a

national

cin~a

section of

secondary (aellfties,

ft

is a-

flmared that

about

60

of all

ROD,

permit

violations

may not be caused

by

poor treatment plant operation

orfisultydesign, hut arc primarily

ainsult ofnicrification

in the BOD~

test.

-

SUMMARY

AN)

CONCZUSIONS

The 30-mg/Lsecondarystandard defined

by

EPA

w~s

initially detived from the 85

DOD,

removal nquiremcnt

in a supaceded

statute

(18 Cfl

601.25).

Because the

BUD,

test typically measures

only

CR01), in

untreated

wastewatces.

but

may also

mesarc

NOD

in

secondary

effluent,

t’edtment efliciency (pcrcont reman)

am be

determined

only

if

the CRUD5 test is

used.

The

EPA

document deflin Log BPWfl

reiterated that secondary.S-

cilities are required

to

remove only

carbonaceous HOD

and stared that the BOO, test

was

primarily a measure

ofcarbonaceous DOD. Therefore,

ft appears that

the

30-

tngj

BODE secondary standani wasintended to Include

only

CROCi,.

The standard

ROD,

test may measure only CBOD,,

or both CBOD, and

NOD.

The

amount

of NOD exerted

in the standard ROD, test depends on thelevel and type

of treatment and

environmental

cc,mtdjtjons.

Available

summer-time effluent data from

40

facilities sbow that

nitmifleationhi the SOD5 test account

for 24 to

86

of

the total

ROD,.

Stnnmnerrtme

crarbonacequs

removal

capabilities

of

secondary ansi nitrihcation

facilities arc

often

significnntlv underesthuarel

by

the

existing

HOD,

test,

At

times. nttriflcaiion can

cause

SODS

test results

to

indicate

poorer

~uaIity

eth

ucrit

when

wastewate-ra

have actually received better treatment

Nitritation

can

also cause

BOO,

v~lucs

to

excc-t-cl

effluent limits set for treatment theilitics~

It

is estimated

tFtat nearly 60

of

the compliance violationsnationwide

may result

from

aitrification occutngin

the BOLD,

rest,

rather than, from improper design or operation. Revision

of

the

SOD,

test to include

only CR01)1 would reduce

improper

reporting

of

compliance

violations

and

pro-

‘wide a more accurate nrcasurc

of

treatment

plant

efR-

ciency

and CRUD,

removal

capabilities.

EPA

is

cur-

rently in the process

of adding the CROD test to the list

of accepted

test

pncaclures

contained

in 40

CFR

Part

136. The

agency

is

also

proposing

changes to

40 CFP..

Part

133,

“Secondary Treatment

lthbrzuation1”

to allow

ue

or

the CR01),

test.

ACKNOWLEDGMENTS

Credits

Pe~onalthanks

ast

&ven

td

eli

of

the regional,

sam,

and municipal

authorilius

who

aided.

in

locating

the

data base

reported

in this paper. Special

appreciation

goes toJames

Young

ofthe Ijniversity ofArkansas,

whose

research on the SOD

test

brought this

problem

to the

ancrrtion

of

EPA.

Although

th.e inforwwicin in this doc-

umenthasbeen funded wholly or in part by EPA,

it

does

net

necessarily reBoot

the

views of the agency snd

no

affidel

endorsent~n,tshould

be inferred.

Anthon. John

C.

Hallis with

the U. S.

Environmental

Protection

Agency,

Washington,

1).

C.

Ax.

the time

of

rho

research, Robert 3.

Foxen was

also

tcith

EPA.

Foxen

is currently president

of

Robert 3.

Foxcn andAssociates,

New

York,

N.

Y.

Correspondence

should

be

addressed

to

John

C

Hail,

TI.

S.

Environ.

Prot

Agency.

40!

ls(

St., S.

w..

Washington. DC

20460.

1468

Journal

WPCF,

Volume

55,

Number

12

Tth(aG

-Prediction of secondary 000s

violatians

caused

by nitrification.?

Nwn~

Tulal

ViuIad~n

ntng

no

-

PercentaGe ci

Twa

&

prncan

-

of feefflujee

vsa$..

riecaean

In soot

*a-.5

yiQI5t~Qfl5 SflnSStRSICCI

Trfckflnç FjItec

133

51

.40

65

AcIvatod Sludge

es

15

a

a)

E2dmdadAi-

54

10

‘I

40

Contact Stabt.zaticn

39

s

2

40

etocho

4

2

C)

0

,

L~oqrj

1G

5

2

40,

Oxidaticri

Otch

4

-

1

1

~0O

‘

Total:

•~$

53

59

It

iS

a

sirnad that

CBW,5 eqtal re

ST

pended sakls (based

en

compliance n~YtiLO&igdata from New Yak state).

---

Waste-water

Analysis

REFERENCES

S.

You1

S.

C.,

‘flcmical

methods

for nitrificadon

eon-

troL”

.1.

Water Pal

Lw..

Control Fed., 45,

637

(197.3).

2.

Dague, B.. R.,

rnhlblfion

of

nifrogaxsus BOO and

tint-

near

pleat

pcdbcezancc

nahmfioc”

.1.

Water

Fothzt

Control

Fed.

53,

1738

(1981).

3.

Sawyer, C.

N5..

and Bradney,

L,

Modereizatioa

of the

BOO

Test

for

Determining ‘the Efficacy of Sewagc Traar-

m~t

Froeesse~Sew.

Wo,kr

L, 1*,

6

(1Q46).

4.

Sawyer and

Mccarty.,

“ChcmL~rayfor

Environmental

Ebginecrs,”

3rd

F4.,

McGraw-Bill Bofl

Co.. New

York,

M.

Y. (1978).

5.

~

Methoth for

Ecasaination

of

Waterand Waste-

water.’~15th Ed.,

Am.

Public Resith i~ssoe..

Washington,

TX

C,

c1920.

6. I8CPR6Ot.25(197fl.

‘7.

Mcmo~~duqj.~

Trcatment

ln(orrnadon—Ae-

den

Measormthun” Finn ~ktojstafl

Adnünislrator for Air

and

Water Programs

no

the Adminisznzro;

Was~jtjgton,

D.C. CFehnsaq’

7,

1973).

S.

lvlernonnduzn,

“Information on theDegror of

Effluent

Re-

ductios Attainebic Through

the

Application ofSecondary

TrcatncnC

Prom

Assistant

Administrator

for

Ak- and

Water

Programs to the Administaxot

in ørart. Washington,

0.

C.

(January 24,

1973).

9.

Weston,

Roy

F.,

‘Proposal

ror

Development

of EffLuent

Guidelines

fist

the

Discharge of Secondary

Effluesus

from

Muuidtsal

Wastewater

Treatment Plants”

Pcescnal corn-

inunitation

from

Roy

F.

Weston,

Inc.

to

Cf.

S. Environ-

mental

Protection

Agency,

Washington,

0.

C.

(June

13.

19’72).

10.

itoy

F~

Weston. toe..

‘Petfixwsnce ciSecondary Municipal

Ttestmcnt

Works.”

Report

prepar&

for U.

S.

Environ.

Prot. Agency, Water Protnra

Oper.,

Washington.

0.

C.

(1974).

-

I 1.

‘~AfternthPeWaEc Managenucut Techniques for Bract erac-

ticable

Warm

Trcstnsct.*

EPA.430/9-75-013.

Ti.

S. En’

“non. Pitt.

Agency, Washington, 0.

C.

(1975).

12.

Pcnttjoa

on

Resolution

of Secondary Treatment Guide-

linest

Mcnioran4uni

from

Rapruenasrives

of

Working

Group from Office

ofResearch and ~

cuitorins

and Office

or

Wares

Enfcntcrnent

to

haituz

5oiphirt.

Chaletan

of

Working Group

(Dcc.

13,

1972).

13.

Osguc.

B.. a..

Wastcwater

Effluent Oryge’s

Demand and

Sata.rn

Response.”

Papec

presented

at

24

Annul.

Crest

Plains Wastcwatcr Des.

Conf., Omaha.

Ne’S.

(IPSO).

14,

Callaway.

O~

and

Young,

1, C.,

“Impact of

Nitrificasion

in $00,

Test

on Control

of

Acth’ated Sledge

t1an~

Univ.

ofArkansas.

Fayetvflle

(1981)

(Unpublished).

13.

flaiticeki, K.. “The Effect orNhdteaticw

Inhibitors on the

Resultsof

the5-DaySOD

Ott

‘jadon.”

Korren Abwasa

(Cer.), 27,

1132

(1920).

---

Attachment B

---

A SOD

bottle

will

certainly

be

included

in

the

environmental

en-

giucexing

dine capsuLe.

BOTh temov-

-

a1

irs measurement,

its

mecTianftni

and

kinetins,

even the

appropriate-

near

of

its

use

in

process

control,

have been the topics

of

more

ens-.

nacriag

research

studies

than

any

other

single charseteStie

of

watt-

water.

SOD

is

care

of

the

fonda.

mental criteria

on

which the design

of

nearly

every

wastewater

teat-

cent plant in the country is

based.

Eien

so,

whether

or

not

it

is

an

accurate

bdicattr

of

the

tiency

of

biological trealnent

pxuce.~eshas

been

the

subject of debate

for years,

apecially

since

the development

of

other rutasuremeab

of organic ma-

serial

in

water

suds

as

chentical

-

oxygen

demand

CCC))

and

total

organic carbon (TOC).

Now

BOTh

has

been

dissected

inta

two

wm-

ponents,

carbonaceous

oxygen

vie—

maud

(CEOD)

and

Difroganotzs

Oay~m.~a

dentaM

(NOD),

tot

still’

another costttaeny.

BOD defined

According to the

15th

edition of

“Standat~ Methods

tor

the

E~-

amination

of

Water

sad

.

Waste..

watcc

ROD

is a measurement of

the

quantity

of

oxygen

utilized

In

the

biochemical

oxidation

of

or-

ganicmatter in wastewaterin a spe-

cific

time

and

at

a

specific

teinp-.

crature..

rt

also measures

the oxygen

used

to

oxidize

inorganic

material

such

as

sulfida

and

ferrous

iron.

It can also

measure the oxygen used

to oxidize reduced nitrogen forms

if

the

organisms-

that

mediate

that

process

(nittiGcation)

are present

A

sample

in

diluted

with

waxer

containing

appropriate

amounts

of

essential nutrients, a culture

of mice

rociganisms

capable

of

degrading

the

àrganic

material

is

added,

the

dissolved

oxygen

(DO)

in

the mix-.

tura

is

measured,

the sample It in-

cp.batedbr~afred

period

(5

days)

at

20°C,

the DO in

the

incubated

sample is

measured,

and the

4lffer-

ettee

between

the

two

measr-

inpgtt

corrected

for

the

dilution,

is

the

5-day

BOTh,

EOfl~.

Simple,

right?

The

analysis

is

aetnafly

fairly

simple

in comparison with some

of

the

Chemical

analyses

for

waste-

wafer,

but

interpreting

the rant

and maintaining the

sthct analytical

quaflty

coufrts! required for a valid

meesarement

era

infinitely

mare

amaplioraed÷

The

analysis

is

an

in-

direct

measure

of

-

organic

material

in

that

it

measures

the oxygen

re-

quite’! for biolosical

stabilizatio.o.

of

that

ciatertal;

as

suds

it

is

easen~-

tially

a

bioassay

procedure.

Ala

though

the

results

indicate

the

amount

of

organic

material

in the

water, they

axe

also a function of the

condition

and

type of

ruicroorgan-

isnis

in

the

sample,

which

are

in

turn s~

-function of

the history of the

sample

itself.

-

The

anct

o~

nitlificatlen

Development

of the

SOD

test be-

gan

around

1270

with

the applica.-

tion

of

the theory

of oxidation to

the

measurement

of

organic

material.

The

teSt was formally

£xttrqduc,d

in

the

3rd edition of “Standard Meth-~

OclS1~iii

1917.

The

ann

major

deaut..

opment

was

she

recowmendadon

of

5

days. as

the standard incubation

period

in

the

7th-

edition

itt

1933.

M®NF~,R

30/30

Hindsight

On

November 16, 1983, the US.

Snvjronmenral Protection Agen-

cy (EPA)

proposed

a

revision

as

the tegatations

governing

secondary

treatnerr

(40

CYR

Part

133)

to

allow,

at

the

discretion

of

the per-

nutting azdhoritiar, substlw.tlort cr125

‘twit

COrUOFWCCOrLY hmor.hgniicaV

wygen

denran.d

(CR00)

JOt the

previous iynit

qf

30

melt

biochemical

oxygen

demand (SOD)

On

effluent

dZscharge

perniitc.

Tire revision is

to

be tetectivety

applied

in

those

cases

what

the

HOD

tat

does

not

vstcuratdy

reflect

the

degree

of

tr~gr~g~

achieved by

th~plant. 41-

though many of the people

who campaigned

for a

regulation cd&vIsthg

this Lance

feel

it

is not erectly

what they had

las ini)yd, the regukrlton has

been so

long in

canting that they are witting

to

settle

for

a

~mronuise.

:71

AprIl

1984

301

---

snumy researceere

had demonstrated

thu

two.-ctag

nature

of

BOX)

exet-

Lion—oxidation

of

only

carbonac-

eous material

for

the

Srst

10

or

12

days of in~bation,and

oxygen

up-

take for itituiticarion

(NOD)

by ni-

frifying bacteria

aftrr

that

time. Au

example

of

the

classic

curve

is

town in Figure

1.

Figure

1—The

SOD

carve

sbowleg

die

effect of

uitdfic*Zon,

In

1955,

the

lOttE

edition

of

“Standard

Methods”

rioted

that

some

samples,

particularly

sesx,nd-

ary effluents or natural

waters,

ccn~

-

tamed established populations of ni-

trifiers, and

thus

nirrfficaticn

could

•

easily begin before

the

end

of

the

5-day

incubation

period. Proced-

ures wets suggested

for

nitriSoation

supreasion.

Nitriflcadon has conS

teody bean referred

to in the liters-

tore

as an intcrference

in

the

DOD

Scat,

rather than

as

a thaxactcthtic

of

interest

is

the

w-astewater.

In-

deed,

a

strong

argument

has

been

wade

that

the

test

wan

never

in-

tended

to

neasare

the

oxygen

de-’

maud

of

nitrogenous

substances,,

and that

the’

ROD

refenad to in the

regulations

governing

secondary

treabtant

should

always ban

been

only

carbonaceous.

‘The

15th

edi-

tion

of

‘tStsxtdard

Methods”

expli-

Sly

states

that

“The

inclusion

of

ammonIa in

rite dilution

water

de-

mourn-ares that

there is no intent

to

include

the

oxygen

demand

of

re-

duced

nitrogen

forms

liz

the

ROD

test.”

Normal

operation

of

activated

sludge

processes

does

not

provide

sufficicat

detention

time

to

develop

substantial

populations

of

nitdters.

These

organisms

grow

slowly

and

require more time

to

establish them-

302

selves in

the biological

process than

do

organisms

that

metabolize

cat—

bonaceoua

materiaL

For

this

rea-

son

raw

wastewater

may

contain

very

few thtrciers,

but as

the waste-

water

passes

through

the

various

processes the

detention

time nay

be

sufficient for thena to develop into an

actively

nitrixying

population.

By

the

time

the

treated

wastewater

leaves

the

plant,. ninilicalion

may

be

in full swing. This can be a prob-

lem

in

plants

that

are

tu-ealing

less

than

their

design

flow

so

that

the

actual

detention

time in

the

aeration

basins is

longer than intended.

-M1sk

nwuhu

The impact of uitriflcation

on

the

ROD

test

is

that the

results of the

anab’sis

may

not

accurately repa-

acne teatnent efficiency. White

the

process

nay

indend

be

stabilizing

carbonaceous

material

so

that

CliOD is

quite

low,

and further ha-

prot~ effluent

quality

by

removing

nitrogenous

pollutants

(ammonia),

the

DOD test

could easily

indicate

little

or

no

improvement

in

water

quality. in

an extgme

case,

the

ci—

fluent

DOD

could actually be

higher

than

that in

the

hufineot

because of

the

inSuenee

of uitrticalion.

-

4

-~tC

rn’?

fla

\/

-“~j

s~

tc~ct.cu

WM ø4Si~ ~tSOO~

=

C

P0

fl

C~I,apc.

C)

Figure

2—Effluent

oxygen

de.uu~sd

data

franz

the

Dnbwzque

Wasftwatar

Ti-salting

Yt~u.

A

plant may very weLt

be rennov-

log even more pclrudou from

the

water

than

it-was

designed

to- xc-

move~

but

seem

to

pedorna

poor-

ly

according

to theSOD

data.

Fig-

urn 2 illustrates

this sitnation~Such

problems

have

led many freeSt

pl~

administrators

to

request con-

struction

&ants

funds

for

Station

faciltics

over

and

above

their

sec-

ondary

processes

for

additional

ROD

removal.

When

EPA

ex-

amined

the

plant

data,

the oxygen

demand

1h4

bad

been

measured

often

included

that

fr°m nitrtilat-

tion

so

that

the plant

was

actually

meeting and

exceeding

its

removal

requirements,

and

removing

am-

nionia

as

welL

Recognition

of

this

problem

saved

many

millions

of

dollars

in

urx~iccessaxyconstruction.

But

what sheet thebottom flue on

the

isain

of

organic

removal—

oxygen

demand

on

the

receiving

water? if the wastcnter

contains an

oxygen

demand

from

nitrugeuous

substances

instead

of

carbonaceous

substances,.

is

that

less

harmful

to

the

stream?

(Translation:

~

demand

by

any

other name.

.

I’)

‘The key to

this

question

is

that

for

the

nitrogenous

oxygen

demand

lo

be

exerted

in

the

attain,

nitrifylug

populations must

be present and ac-

tive

there.

While

these

organisms

way thrive in treatment processes

øt

the

SOD

bottle

where

conditions

favor

their

growth

and

where

they

arc ~nruth

more

concentrated,

they

may

not

be

able

to

manifest

their

effect in the

receiving water.

Nitrilicadon

in

action

The

sigeificanca

of the

ttrt5aa-

lion problem is

clearly

illustrated

by

the

experience

of

the

Colorado

Springs

Utilities

Department Waste-

water Division. In

the

fall

of

1979,

plant management suspected

the in-

terference

of

nirrificatton

in

their

DOD

tests.

They

began to

analyze

their

samples

in

duplicate,

cue

by

the standard DOD method, and

one

sample

with

the

addition of a them-

ical to

lnljlbit ujttlficatlon.

These

xc-

stilts

verified

the suspicion,

and they

-

requested periulacion fromthe

Cole-

ratio Department

of

Health

Water

Quality

Control

Division

to

report

the results

of the inhibited SOD

test

because

their

stanclanl

ROD

data

was

erroneous.

Because

EPA

had

not

approved

the

inhibited

ROD

method far

use in

compliance test-

ing, the state denied the

request and

Colorado

Springs went to the EPA

XomnaL WPcF, VoLume S6,

Ntunber

4

C,,.,.

~

_

-

-

It,-

$

---

Region

VIII

administrator

to

re-

quest

modification

of

their penuit.

However,

EPA

headijuaslets

maintained

that

the

~1fl/34y’

(30

rug/L

BC),

and

30 ing/L

suspend-

ed

solids)

efflucnt

Thnitation

had

been

intended

to

include

the

inci-

dental

contribution

of ~-NOD,

end

so

a

reddnidon

of

the

parameter

and

a review

of the

numerIcal

limi-

tation

would

be

necessaiy.

This

latmebed Colorado

Springs

on

a

4-

year strug*

with

state sea

federal

regulatory

agencies

that

iuehtdcd

a

campaign

dE

Letters

to their

state

legislators

and

three

difterent

EPA

.Administnton.

They

also

sponsor-

ed

an in-depth

study by

Owen

Cal-

laway

and

lanes

C.

Young,

the

801)

Task

Force

ohainnan for

the

•

“Standard Methods”

Joint

Editorial

Board.

Al-though

the

technical

groups

in

the

various agencies s~-

cd

to

understand

the issue and sup-

port

Culorado Springs’ request,

the

dispute

became

essentially

2

legal

battle.

J~Jab

ioao

Colorado

Springs

solicited

the

help of the

?1ssodafiou

of

Metropolitan

Sewerage Agendeq

(AMSA). AMSA surveyed its

mem—

ben on the

qucstlen

of

compliance

with

EPA

secondary

ueatgreut reg-

ulatons

in

plants

with Seifiad

at-

fluenre.

01

71

plants

surveyed,

41

experienced

incidental

nitrificadon

hi

tha

secondary

systatas. In

41

of

those

plants,

tire

effluent

ROD

was

artificiaily

high

as

a result

of

nittification;

NOD

represented

be—

tween

9 and 86

of the total SOn.

Of the

plants

with

incidental

iii-

trifleatiori,

34

responded that they

had

experienced

compliance

prob-

lem;.

The

survey

concluded

thgt

plants

with

anupliance

problems

“generally

implemented

facUlty

or

operating technique

modifications

at

additional cost it’ an attempt to Con-

trol

the

partial

nitrificafion

or at-

tenuate

Its effects.” In marty cases it

was

not

initially

clear

that rtiwlflea-

lion was

the problem, and remedies

such as

the addition

of gravity flitru-

lion mentioned previously were con-

sidered.

Some

higher-than-expected

Apr11

1984

-

~0D

results were interpreted simply

a~

inadequate

biological

treaunent.

and

measures

such

as

increased

Stratton

were

IriS.

This

served

to

encourage

nithflcntiçtn

arid

Sara-

vaSe the

probleuL

When

nitrificarion

was

identified,

some

plants

de-

creased

their

mixcd-ltqtzor

DO and

wound

up

with

a

sludge

hulking

problem

to

add

to

their

woes. Al-

though a

decrease in mean

cell resi-

dence

time

(MCRT)

Would

help

discourage nitrificatton~

It often

pr0~

dated a sludge

disposal problen

InMim,~,n5a

Paul, theMetro-

politan

Waste Control

Corn

mbcsj~~

(MWCC)

began

struggling

with

the

nitrfficarion

Interference problem in

1975.

tinder summertime conditions,

their

ROD

wà~

any-whoxu from half-

again

to three

times as

high

as

nor-

mal. Once they established that

their

problem

was

not inadequate but ac-

tualLy

excess

treannent

efficiency,

they

began

unsuccessful

efforts

to

have

their

permit

rewritten

far

CHOD.

After trying

such methods as

reduced

aeration

arid

additional

sludge wasting,

they

finally

bit

on

a

reliable way

to

eliminate

the

nitri-

Ears in their effiuent—bvoxchloriaa-

don.

There

was

no

question

that

this

practice

was

not

envimunmen-

tally

sound.

but

it

did

bring

thth

cthrcnt

SOD

with.in

the

lImits

of

their permit. In 1931, adlspute -with

the

Minnesota

Pollution

Control

Agency over

the

practice

of

year-

road

chlorination produced a stand-

nE

of

sotts.

The

MWC’C

discon-

tinned overchiorination

and

now re-

ports data

for both

CEOI)

and

total

-

ROD

to

the

state

to

demonstrate

their

good

faith

eflorts

to

comply

with

their

permit,

but

theoretically

the

state

could

initiate

enforcement

action

at any titus.

E~Lorccment

prerogative

A

much more

heated

battle with

the

regulatory

powers

occurred

ii.

Dubuque,

Iowa.

The city’s

problem

with nittificadon

stemmed

from ef-

-

forts

to

control

a

problem

of

ex-

cessive solids

in

the biological pro-

cess.

Increasing

the

sludge

age

to

facilitate

solids

handling resulted

in

nitrificatiqu,

nor In the plant

but in

the

DOD

bottle.

Their pnhlezn

was

brought to the attention of theIowa

Department of Pnvironmental QnaL.

ity in late

1978- In

a situation situ,

lar to that in Colorado

Springs, they

found

that

the

regional

engineers

wdre

receptive

but the- pniblein was

held

up administratively: Eventually

the

city was

threatened

with retro-

active flne~of

$10000/day

which

would

have amounted to millions of

dollars.

An

out-of~courtsettlement

required

the

city

to

take

several

eaeaures

directed

itt

correcting

their

solids

handling

pro~blonsand

pay

a line

of

$15

000. lb

consent

agreement

provided

for

the

use

of

the inhibited

HOD

teat for a specific

period

Now

The

city reports

both

CECiD

and

ROD

to

the

state, and is

planning

to

take

advantage

of

the

opportunity

to

have

their

permit

modified permanently.

-

Nitriflcation

and

process

mediS-

cations

to

control

£t

can

often

re-

salt in

other problems, not just with

operation

but

with

compliance

as

well.

Partial

nitrifleation

in

a

plant

produces

excess

nitrite

concentra-

tions

which play havoc with the re-

actions

of

chiorhie

disinfection.

A