NC0040070_Staff Report_19960502

SOC PRIORITY PROJECT: Yes —No X
If Yes, SOC No.
To: Permits and Engineering Unit
Water Quality Section
Attention: Mark McIntire
Date: May 2, 1996
NPDES STAFF REPORT AND RECOMMENDATION
County: Gaston
Permit No. NCO040070
PART I - GENERAL INFORMATION
1. Facility and Address: Gastonia Water Treatment Plant
313 N. Falls Street
Gastonia, NC 28052
2. Date of Investigation: April 25, 1996
3. Report Prepared By: Todd St. John
4. Persons Contacted and Telephone Number: Randy Hawkins [phone]
7
5. Directions to Site: This facility is located at the intersection of Falls Street and Long Stfeetr Aires,
in downtown Gastonia. 11 as c.Vw n� ex)
6. Discharge Point(s). List for all discharge points:
Latitude: 350 16' 06" Longitude: 810 11' 16"
Attach a U.S.G.S. map extract and indicate treatment facility site and discharge point on
map.
U.S.G.S. Quad No.: F14SW U.S.G.S. Name:
7. Site size and expansion are consistent with application?
Yes X No_ If No, explain:
8. Topography (relationship to flood plain included): The facility is located in a gently sloping
area. This facility is not located in a flood plain.

f.
l
9. Location of nearest dwelling: Approximately 100 feet.
10. Receiving stream or affected surface waters: UT to Long Creek
a. Classification: C
b. River Basin and Subbasin No.: 030836
C. Describe receiving stream features and pertinent downstream uses: The receiving
stream is approximately 2 to 4 feet wide with a rocky bottom. This stream appeared
to have typical class C uses.
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of wastewater to be permitted: 1.2 MGD (Ultimate Design Capacity)
b. What is the current permitted capacity of the wastewater treatment facility? 1.2 MGD
C. Actual treatment capacity of the current facility (current design capacity)? 1.2 MGD
d. Date(s) and construction activities allowed by previous Authorizations to Construct
issued in the previous two years: N/A
e. Please provide a description of existing or substantially constructed wastewater
treatment facilities: The facilities consist of two settling basins and a sludge
dewatering press (not in use).
f. Please provide a description of proposed wastewater treatment facilities: N/A
g. Possible toxic impacts to surface waters: None
h. Pretreatment Program (POTWs only): N/A
2. Residuals handling and utilization/disposal scheme: Land Application
a. If residuals are being land applied, please specify DEM permit no.: WQ0001793
Residuals Contractor: Amsco
Telephone No.:
b. Residuals stabilization: N/A
C. Landfill: N/A
d. Other disposal/utilization scheme (specify): N/A
Page 2

1
3. Treatment plant classification (attach completed rating sheet): Class I
4. SIC Code(s): 4941
Wastewater Code(s) of actual wastewater, not particular facilities, i.e., non -contact cooling
water discharge from a metal plating company would be 14, not 56.
Primary: 21 Secondary:
Main Treatment Unit Code: 51003
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant Funds or are any public monies
involved (municipals only)? N/A
2. Special monitoring or limitations (including toxicity) requests: None
3. Important SOC, JOC or Compliance Schedule dates: N/A
4. Alternative Analysis Evaluation: Has the facility evaluated all of the non -discharge options
available. Please provide regional perspective for each option evaluated.
Spray Irrigation: N/A
Connection to Regional Sewer System: N/A
Subsurface: N/A
Other Disposal Options: N/A
5. Other Special Items: None
Page 3

PART IV - EVALUATION AND RECOMMENDATIONS
The City of Gastonia has applied to renew the NPDES permit for its water treatment plant.
The facilities appear to be well run and maintained. Therefore, this Office recommends renewing the
subject permit.
Signature of port Preparer
Water Quali Regional Supervisor
Date
Page 4

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RATING SCALE FOR CLASSIFICATION OF WATER POLLUTION CONTROL SYSTEMS
Name of Facility: �tGt
5 �h 'c°t
hl
Owner or Contact Person:
Mailing Address:
�% �'"� 1
7�f rrrs�ur
�a a — /75`9
County:
Present Classification:
NPDES Per. No. NC00 4 9 '7v
Rated by: Todd fr. Jchn•
Reviewed by:
Telephone:
New Facility_
Nondisc. Per. No.WQ
_ Telephone: 70(1-6,63
Health Dept.
Regional Office
Existing Facility
Health Dept.Per No.
-/6 — Date: 9�
Telephone:
Telephone:
Central Office
Telephone:
ORC:
Check Classification(s): Subsurf ce
Wastewater Classification: (Circle One)
Grade:
Spray Irrigation
II 111 IV
Telephone:
Land Applica •on
Total Points: IA -
CONSIDERED WASTE 7REATMe4T FOR THE
PURPOSE OF CLASSIMATM
ALSO SEPTIC TAN(
ANK
COhMTNG OU Y OF SEPTIC T
AND GAAVrTY fM F7C"TION I —Mr, A.oF EXEMPT
FROM CLA
SIFICATICN
SIIBISIIFiFACE CLASSMATION
(check ail units that apply)
1,__._septic tanks
2._pump tanks
3. _-siphon or PkmP-dostng systems
4—sand fitters
5. _ _grease trap/nterceptor
6 od/water separators
7—gravity subsurface treatment and disposal:
S._preswre subsurface treatment and disposal:
SimpAY ItifvGAT10N CLASSIFICATION
(check all units that apply)
1_praliminary
treaunent (definition no. 32 )
2.
Igoons
g`_saptic
tanks
4.__pump
tanks
S.
_pumps
6
sand fitters
7—grease
tnapinterceptor
tti.
_oit/water separators
S_dlainfection
10._._c
emical addition for nutrient/algse control
11 .—_spray
Irrigation of wastewater
In addition to the above classifications. pretreatment of wastewater In excess of these components shall
be rated using the point rating system and will require an operator with an appropriate dual certification.
LAND APPLICATION/RESIDLAALS CLASSIFICATION (Applies only 10 Pw"* holder)
1. Land application of biosolids, residuals or contaminated sods on a designated site.
WASTEWATER TREATMENT FACILITY CIASSiFICATION
The following systems shall be assigned a Class 1 classification. unim the flow is of a significant quantity or the technology IS unusually
complex, to require consideration by the Commission on a case -by -ease Mask: (Check d Appropriate)
1. C&wster Separator Systems consisting only of physical separation. pumps and disposal;
2 Septic Tankd Filter Systems ownsting only of septic tanks, dosing apparatus, PumPs.whd filters, disWedon
Ban
and direct discharge;
3..._Lmgoon Systems oonsktirg orgy of preliminary treatment. lagoons. pumps, disinfection. necessary chemical treatment for
algae or nutrient control, and dsect discharge:
4,_ _ poaed-boP Royce Systems:
S,_Groundwaler Remedistion Systems consisting only of dl/watw separators, pumps, air -stripping, carbat adsorption. disinfection
and
6. _ fture cpsrattons with discharge to surface wales:
7 Water Plant sludge handling and back -wash water treatment:
ati Seafood processing consisting d screening and disposal.
O _Single-farnly discharging systems. with the exception of Aerobic Treatment units. will be classified I permitted titer July 1.
19Q3 or tf upon Inspection by the Division. it is found that the system is not being adequately operated or maintained. Such
systems will be notified of the classification or nxissallication by the Commkokx% in writing.

The. following scale is used for rating wastewater treatment facilities: (circle appropriate poinis) ;
POINTS
ITEM
al PnetrvW"Wt pMWUm (Seedaffroon No....»....».».».„.:.........4
(1) Industrial Pntresnrnt units or � applicable to nprtoomarnWM Wd cooing usla s, skrdae handing facilities for
(2) DESIGN FLOW OF PLANT IN domed � �g�� definition No. t 1), one taalties wnersktp " of No
water pwificstion plants. lotalh
(4xd) or Moms (4)(d) and (11)(d11 ._.............—r....__......_.............^.......»..........»------1
60.001 -- 100 000. �M 100.001 - 250.000...».......................... �....� M----3
.....................�..»............_....
i00.001 - 1.000 000.....».............................._....... —_... — ��--------��'^"'.M�. � 30
1 000.001 - d UP) fate of � WW for each 200.000 gpd �b UP 10 a tna*MM d .»
2,000.001 (and UP) rate 1 pt>ka addit
(S) RY�U ffSMFIOn Pow CESSES (No aektition No.22) ^ ..�__. . ....»..t
or_ __ _ _ _ , . _._._._.
(b) Wehanical screens. Static Screens or Commirarting Dwbgs- » .»-� ^.» __»......... ,,1
(c) Oft fiornoval».».................»...........».......... »...... 2
or_._.. »... ......»...._........ »»..»--...
M Flow
(f) °ostrumo p Ma&=rement........ ___ _.» ._. » . ...._..M.�.-. -. w. » »_.......» ........ w ." .»». 2
( h ) Inituert Flow (�uapxatbn.». _ter _...���_.».» » . » . ... » .... _2
(I) Grease or oil separators - Gravty. ...,_, .».«..........._.r .......................
Mechanical......._...._
Olseolved At Rotation ....._..... ......_._...--.»............ .'.""".'..._._....................._.....» .»...3
(4) pp ppfww-ATMi3druNffs"=ESSES �...w.»--•.2
(a) Septic Tank (soo d*IWtbn No. 43) ». 3
I(b) knhofl TarYc ......... .............._._ ..-.-------- y �..._ ..... _.5
Primary Clatklera_---�-�"-' (p) eMack kAaarlsk (sN+dgs handtlr+0 faeiWs for water
( ) Ponds or SeWing Tanks for lno; ri reussfontal such as gem
d or ica n pWaa, and Ord. Morn. and other mining apordbns o><esPt �...... »..... » ».»2
(5) old
�phf1VTFIAIMENNT u�T5tPF10C 5 0
(a) (iGreonaoeotrs aWMratbr►-Hph Purkp Otcppon oritom.-....._—_....».»............-10
OMlused Air Spstem. ........_.....» ..... _�._ .... 3
Mtchardcsl Air Systam Mx9d. floating or rotor)
Separate Skrdge
N) Trickling Filer �..-.,- »....7
HighRats._.... �.." .......»»5
Standard Rate... ........»..» . 3
hckad Tower. » . _. 10
lM) oiological Aerated Few or Aerated Bblog" Fltlor 0
(w) Aerated l,agoona. -- . ,,,_.._..........................»_
(v) IAwating Skkgical Contactors-....-.....
aortal Filters-Irtenrtttert ......._...-»----•---„~_-.
(w) Recirculating
3
Lagoon! �w p n�oews rereroval d BOOand n �d by
(t) Stngis swag system for contbirMd In addition to home
1ltMixtbn (see defWtion No. 12)(Poats for this ltNn have tope
(5)(a)p) through (5)(a)(01). __..2
ddYlltltl^ ff° �)
LVnh+g the exurded aeration proem (act° e
ettlsing other then the extended aoradon r,^�„_,,,,,,,„3
Wtrtrlera additions to enhantos BOD removal_ ..-__..._3
elological culture ("Supor Bugs'IddkiD^.^—^'.�
(p) (iNlvogerqus fftspe - - '0
Aeration • No pwitf M
oxygen sISO 10
Diffused Air
Lilechniftal Air System Mzsd. fbating or raorl,
S)leparwtg Stodge Fleaervdon._.-_ - -- "— 7
(p) TAddna Fteahltgh .»........ a
Standard Rate- S
'webs Tower 10
ebioaiol Aerated F111orr or 91cloglicalFIW _ ..10
..._.2
l�) 3
(s) IERTl WORAOVANC®TFEAIMB4TUmaSrP 3
t) Aadvated Carbon Bods -
( without owrbon 1 s
with carbon reganwatbn-
(b) Pbwdwed or Grararlar Activated Carbon Fear} 3
tdh carboon iepet�� ^ 6 ___ t
B
AY stripping _ 10
DeroArscationProcess -3
It) Foam sepam -�
Ion Exchange------ -- its Np fib) (nil applicable for sand.Ord �w
�h) Lard Application of Treated EflA+ert (see
and other Nmltar MWntg opentl a) by high rate 00—
1 i PhosphorousiMmoval by Bbbgkal Processes (See dslYrltfont No.
Pow*v Ponds - without .- --j
with M
i

. 0
Post Aeration • cascade ................... ......_....».....»...............«....................................................................2
(1 dmused or m.chu+ICaL.....................«...........................................................
...................
(r")Flevorse Elites law rate.........•.-........._...._..._...._..-.-»._...._..._...._...._..._........_........._.
(n) Sand or IAI:.d 1Aedia high tat............« ..................................... ...................5
for removal of metal or ryanide.............. than «.etas Of••••».•»• ................... ..............
:..».t 5
(°) Trsa>rnaK Pan K for removal of m:k mat.rfals otln.r than metal or ryanid...•_-•----..._.-._-__.,._.t 5
(T) (pat ACsE �ddge 0� • Tank Heated (ansarobk).._.» .. . _ ..«.... _ « •• _ «. _.........'3
Asombic
Unhassed
»n.. aea)
�) Sludge +»2
Sludge p Bed�CravkyM_.__..«.............
acuum
(VSI��� _ ...........5
udnditioner(chemicaorha.M...5
ThkMn.(Slugravity)..�NM....... .....
t!
(g) Olasolved AI Rotation Unit [not applicable to a )unit rated as (3)(0)_.» .....N « • " . «.-. __ .« « .2
(h) Sludge Gas Utulzation (including gas .«...
..«..« .... .«« ._..._...«.... .«.. « «... « ...».«.. 2
(i) Sludge Holding Tank /lerated.�... «« .......... ...».».........» ... «.............»».. «.«. ».....
Non•sersl.d...«.« .«.-...«.... �hnted carbon r+g.^.ration)....» _»..«.««._....«.»«.... »-_� 10
([) Sludge Incinerator (not including or other similar devrater+ng devkee..- _ _� ___».__
k Vacuum Filter. ISPOSCentrifL (i cl Filtdings ed ash)
(6) RESIDUALS UTILQATIOPUDISPOSAL (including ...._._.«............ ........ .. .............. 2
........ «............... » ...«.
(a) L.aagons......... ........................ ...».....»...... tlrition 22a
(b) (jnd Application (suds" and subsurlaoe) (ae. d. ) son emit
by to a lad application operator or landfill operator who holds the
land application p! .= 2
or landll permit. .... ........ •• a -so wastewater treatment taegity_. »_. _._.�..._.-.._....5
(c) Osdkated Lartdki(burial) by the PsrtrYttes
(dl rkhabon ......-.. µdstWtlon No g) (not appikabi. tD dem�+i addition rated as rent
(� p) CHEMICAL ADDrt10Pi ). (7)( ). (see points each:
pxa*l). (6xa). (6)(bl. (n(b)• (7)(e).(fla),(g)(b) or (>a)(c) `' Po ....»_..... _ ..........___ _..»«_..»
11 > 1 (a�MSES j.biding Tanks or Settling Ponds for Orgatk or Toxic IdateAak wastes from mining
nl nit phosphorus compounds in amounts sign er than is common
operations containing nitrogen or ..«..».s
for domestic wastewaur...».__...... . ••- basins which are Imilm m In land appGestlon systems)---2
(b) Stage Flow " Discharge (not � (not alto � basirs IthOr" In lard aPPlkatlo^
(tit t nod ByPowe SuPPIY ......« = M_... w_.»...��.........».«._.»......_............_...._._ - -_..' »3
Thmd Pollution Control Device • • TOTAL POIMS ��r_......-..-.»_— —~w-'-."w.r.-
or .»_...--
Q.ILSSFMTIOTI
..._ _..w5.25 Pouts
C1s i II .«.._«--..._-.- .««.»...�__... �_......._.....--26-50 Palms
...�........6 ff5 Pouts
Class
chns ",-Up Palms
Class IV
Faefittiss hawng a gating of sets Uwugh bur pokas. Itdusiw, do not require a M11 opaato -
Fadlai.a towing an satvated atrrdg. Prooees wfl be assigned a ml*MM dusMication of Gass IL
FacMdes hw*q trsatrrrsnl promeas for the removal Of ntatal or @V M wo be assigned a mlrmamn daaski=*n of Crass IL
phoaphonra w• be assigned a minlnum dsestioatlon of Class Of-
Fidei.s he"trsatnwt prwews to►1M bbb¢oai removal d
The fofowlnp lNtdN bens shale apply throu0l+oot 1� S�ePt�' Mc mderlal from wasnwat r eMwnt:Tie oopnr+MW Oeds Car o this
1 Activated Carbon Soft A pinyskavet+•mlcal method for reducing soluble pigs loot and mtybe elther w a dowrtlow orboh beds Carbon "� °f
(�E)Y4
will � a lbw eau varying from two to eight ti+ks"a per ttwwta Per �
regenerated an the wastewater trsamersPl site:and bywhich biologi al �bn or organk mallet, is reduced thtough ett�yLagoons. A basiOn which at sok k are mai tained fn " ordituabnx3atrartaler d as enb a flow though basis: oxygen in a liquid by @Pnr ng. 89liatiOn
(3) Ae�lort. P�m about Itlnw aoratact between air a high purlly ho
Aeration. M aoivated akrdpe prooeee utt"; a mrirnMrwm hydrauitc dMerrbn tined 16 tours tnhades . �� frets, ere.):
Any alto on which a crop Y produced. managed• and harvested (�P udesI ) wllh inns atmhonia then ralsaead to ft
N) A k`� t which tie ammordum ion is lust oorwsnad to dissolved amuronla (PH adj _
�atrttosphsm by physical means: or other sltnkar proosssss which totaws d a b provide Wch as aextrams7 tigh tert4are w and fa>rfdsa the
urea which vofsdba
��Carbon roRb� The regeneration d exhOJtted Moon b1
the s1111"t k1ft of delersrt darttldas:
m Carbonaceara Stage. A stags d wasuwsi n tr.aatbt do add" � front kquids or to saparsts k4u
(� Certrftgs. A mechanical oevb h which centrifugal forts kcstion pokt tar purposes d Iarpnwlq sokds removal PH ad)ustron*
(9) Chemical Adclean Systems- The addition d chemical(s) a �rhemicalsra19 rrd�d Orlin application pouts to achieve a q•ckic result o p confor dild ore
skal my control. etc: ttte capabotY to �r m@irt wkh Abe r teal a kob to sdd a chemical at a dlhlerent appkcatbn pouts to dltierert
system; the cspabmty to add chemkal(s) to dual unks sal be rated as ore system: upabiktY b ooalnn tie mass p b
purposes wS resuk In the systems rated
da deice"+ � MIS;COMnd such s kms. Mink C hlorlde, or a P* w b wM Aldge
(10) Ctemrkal Sludge Cording deg non -toxic matiamb from cad. 1F�
Ib application b a d.watnning devtos' tanks for cortalrxtwt d wastewater oon �r+lnpmInorganic. taciktiss or any other appun•renosa:
inns Use d ► P�'& or h�"gImurntwo rink effluent krnhs on BOD
crushed storeeoorr otho er sknitar op•rationt_ Such sysems sfialus Removal M Nukicatbn- Palms "isregardless
WO system requusd to achieve p•
(12) Comblmd Removal d CarbonsONKM BOO and Muog•
end ammonia nitrogen wkhin the sate biological hector, or PhYsky prooeea;
_.._ j, &.4.,dter. alreeidual chto" In a itquld by arty dwmkml

(/7) Foam Separation. The planned frothing of wastewater or wastewater effluent as a means of removing excessive amounts of detergent materials through
the Introduction of air In the form of fire bubbles; also called foam fractionation;
(18) Grit Removal. The process of rernovi g grk and other heavy mineral matter from wastewater;
(19) Imhoff Tank. A deep two story wastewater tank consisting of an upper sedimentation chamber and a lower sludge digestion chamber.
(20) instrumented Flow Measurement. A device which Indicates and records rate of flow;
(21) ion Exchange. A chemical process In which ions from two different molecules are exchanged;
(22) Land application:
(a) Sludge Disposal. A final sludge disposal method by which wet sludge may be applied to land either by spraying on the surface or by subsurface injection
(I.s., chisel plow); (not applicable for types of sludge described in (11) of this Rule);
(b) Treated Effluent. The process of spraying treated wastewater onto a lard area or other methods of application of wastewaterjorto a land area as a
means of final disposal or treatment;
(23) Microscreen. A low speed, continuously back -washed, rotating drum filter operating under gravity conditions as a polishing method for removing
suspended solids from effluent;
(24) Nitrification Procass. The biochemical conversion of unoxkiized nitrogen (ammonia and organic nitrogen) to oxidized nitrogen (usually nitrate);
(25) Nitrogenous Stage. A separate stage of wastewater treatment designed for the specific purpose of converting ammonia nitrogen to nitrate nitrogen;
(26) Phosphate Removal, Biological. Tie removal of phosphorus from wastewater by an oxidanoxic process designed to anhance luxury uptake of phosphorus
by the microorganisms;
(27) Polishing Pond. A Adding pond following secondary treatment with sufficient detention time to allow "tiling of finny suspended solids;
(28) Post Aeration. Aeration following conventional secondary fragment units to Increase effluent D.O. or for any other purpose;
(29) Post Aeration. (Cascade) A polishing rnethod by which dissolved oxygen is added to the effluent by a nonmechhanical, gravity nears of flowing down a
pries of steps or weirs; The flow occurring across the steps or weirs moves in a fairly thin layer and the operation of the cascade requires no operator
adjustment; thus, zero points are assigned even though this is an essential step to meeting the limits of the discharge permit;
(30) Powdered to Granular Activated Carbon Feed. A biophysical carbon process that utilizes biological activity and organic absorption by using powdered or
granular activated carbon; Virgin or regenerated carbon is teed controlled Into the system;
(31) Preaeration A tank constructed to provide aeration prior to primary treatment;
(32) Preliminary Units. Unit operations In the treatment process, such as screening and comminution, that prepare the liquor for subsequent major operations;
(33) Industrial Pretreatment.
(a) Pre-treatment Unit, Industrial. The conditioning of a waste at its source before discharge, to remove or to neutralize substances khjurious to sewers and
treatment processes or to @Had a partial reduction In load on the treatment process which is operated by the sane governing body as the wastewater
treatment plant being rated;
b) Pre-treatment Program, Industrial - must be a State or EPA required program to rem" points on the rating shoot;
(34) Primary Clarifiers. The first coming tanks through which wastewater Is passed in a fragment works for the purpose of removing settleable and suspended
solids and BOD which Is associated with the solids;
(35) Pumps. A8 influent, effluent and in -plan pumps;
(36) Radiation. Disinfection or sterilization process utilizing devices emitting ultraviolet or gamma rays;
(37) Reverse Osmosis. A treatment process in which a heavy contaminated liquid Is pressurized through a membrane forming nearly pure liquid free from
suspended solids;
(38) Rotarirg Biological Contractors. A fixed biological growth process In which wastewater flows through tanks In which a caries of partially submerged circular
surfaces are rotated;
(39) Sand Filters:
(a) Intermittent Biological. Filtration of effluent following septic tanks, lagoons, or some other treatment process in which further blodexpmposltbn s
expected to produce desired effluents; Hydraulic loading rates on these filters are computed In gpdrac and have a resulting low gpmist (less than one):
b) Recirculating biological - the same type of wind filter as defined In Subparagraph (39) (a) of this Rule with the added capability to recycle effluent back
through the sand filter,
(40) Sand or Mixed-Medla Filters. A polishing process by which ef0uent limits are achieved through a further reduction of suspended solids;
(a) low rate — gravity, hydraulically loaded filter with loading rates In the one to three gpmrd range;
(b) high rate — a pressure, hydraulically loaded fitter with loading rates in the five gprrVhd range; At any rate, the loading rate will exceed three gprrVef;
(41) Secondary Clarifiers. A tank which follows the biological unit of treatment plant and which has the purpose of removing sludges associated with the
biological treatment units;
(42) Separate Sludge Reiteration. A pan of the contact stabilization process where the activated sludge Is transferred to a tank and aerated before returning It
to the contact basin;
(43) Septic Tank A single -story settling tank In which "filed sludge is in contact with the wastewater flowing through the tank; shall not be applicable for
septic tank systems serving single family residences having capacity of 2,000 gallons or less which discharge to a nitrification field:
(44) Sludge Digestion. The process by which organic or volatile matter and sludge is gasified, liquefied, mineralized or converted Into more stable organic matter
through the activity of living organisms, which includes aerated holding tanks;
(45) Sludge Drying Beds. An area comprising natural or artificial layers of porous materials upon which digested &*wags sludge Is dried by drainage and
evaporation;
(46) Sludge Elutrlatlon. A process of sludge conditioning in which certain constituents are rAwreed by successive washings with fresh water or plant effluent;
(47) Sludge Gas UtIlizatlon. The process of using sewage gas for the purpose of heating buildings, driving engines, etc;
(48) Sludge Holding Tank (Aerated and Nonaerated). A tank utilized for small wastewater treatment plants not containing a digester In which sludge may be
kept fresh, and supernatant withdrawn prior to a drying method (i.e. sludge drying beds); This may be done by adding a small amount of air simply to keep the
sludge fresh, but not necessarily an amount that would be required to achieve stabilization of organic matter. A nonaeraled tank would simply be used to
decant sludge prior to dewatering and would not allow long periods (several days of detention) without resulting odor problems;
(49) Sludge Incinerators. A furnace designed to bum sludge and to remove as molsture and combustible materials and reduce the sludge to a sterns ash;
(50) Sludge Stabilization (Chemical or Thermal). A process to make treated sludge less odorous and putrescrble, and to reduce the pathogenic organism
content; This may be done by pH adjustment, chlorin dosing, or by heat treatment;
(51) Sludge Thickener. A type of sedimentation tank In which the sludge is permitted to senle and thicken through agitation and gravity;
(52) Stabilization lagoon. A type of oxidation lagoon In which biological oxidation of organic matter is affected by natural transfer of oxygen to the water from
air (not a polishing pond);
(53) Stand -By Power Supply. On site or portable electrical generating equipment;
(54) Static Screens. A stationary screen designed to remove solids, including non -biodegradable particulate (tlostable solids, suspended solids and BOD
reduction) from municipal and industrial wastewater treatment systems;
(55) Tertiary Treatment- A stage of treatment following secondary which Is primarily for the purpo&* of effluent polishing; A settling lagoon or sand or coal filter
might be employed for this purpose;
(56) Thermal Pollution Control Device. A device providing for the transfer of heat from a fluid flowing in tubes to another fluid outside the tubes, or vie versa;
or other mean of regulating liquid temperatures;
(57) Thermal Skdge Conditioner. A conditioning process by which heat Is added for a protracted period of time to Improve the dewaterabltlty of sludge by the
solubiYzkhg and hydraultzing of the smaller and more highly hydrated sludge pantries;
(58) Toxic Materials. Thou wastes or combinations of wastes, Including dlssa&*-causing agents which after discharge and upon axpowre. I gesdom Inhalation
or assimilation Into any organism, either directly from the environment or Wirectly by Ingestion through food chains, will cause death, disease, behavioral
abnormalities. cancer. genedc mutations. physiobgkal malfunction (including malfunctions In reproduction) or physical deformations. in such organisms or their
offspring; Toxic materials include, by way of illustration and not pmltatlon: sad. cadmium, chromium, mercury. vanadium, arsenic. zinc, ortho-riftro-chbrobentzere
(ONCE). poychlori ated blphenys (PCBs) and dichbrodip" trnchbroalharhe (DDT); and any other materials that have Or may hereafter be detertnUsd to have
1=11c properties;
(59)
(59) Trickling Filter. A biological ttsatrrherY cant consistingof a material such as Woken store or rock our which wastewater In distributed; A thigh rate trickling
Mar Is one which operated at between 10 and 30 mgd per acre. A low rate tricding filler Is ore which is designed to operate at ore to lour mpd per acre:
(60) Trickling Filter (Packed Tower). A plug now type of operation In which wastewater flows down through successive layers of media or filtrate material; Organic
material Is removed continually by the active biological fixed growth In each successive layer. This method may produce 'secondary, quality sffkrent, or may be
adapted to produce a nitrflied effluent;
(61) vacuum Faer. Centrifuges. or Filter Presses. Devices which are designed to remove excess water from either digested or undigested sludge prior to disposal
or further treatments.