Sewage Works Journal, Vol. 13, No. 1

S E W A G E W O R K S

/;

v o l. xiii J A N U A R Y , 1 9 4 1 n o. i

S p e c i a l F e a t u r e s

A c t i v a t e d S l u d g e B u l k i n g — R u c h h o f t — H e u k e l e k i a n

Electrolysis in D i g e s t i o n T a n k s — P a r k e s

M e c h a n i c a l E q u i p m e n t — J o h n s o n

S e w a g e F l o w s a n d C o m p o s i t i o n — R a w n

S e c o n d A n n u a l C o n v e n t i o n N e w Y o r k C i t y O c t . 9-11, 1 9 4 1

3 8

O F F I C I A L P U B L I C A T I O N OF T H E

F E D E R A T I O N O F S E W A G E W O R K S A S S O C I A T I O N S

v o l ' l l

F E D E R A T I O N O E S E W A G E W O R K S A S S O C I A T I O N S

OFFICERS

Chairman

Ch a s. A. Em erso n, Consulting Engineer, Havens and Emerson, 233 Broadway, New York, N . Y.

Vice-Chairman

Lin n H . En s l o w, Editor “ Water Works & Sewerage,” 155 E . 44th St., New York, N . Y.

Honorary Secretdry-Treasurcr

H. E. Moses, Chief Engineer, State Dept, of Health, Harrisburg, Pa.

Business Manager

Ar t h u r A. Cl a y, Treasurer, The Chemical Foundation, Inc., 654 Madison Ave., New York, N . Y.

Editor

F. W . Mo h l m a n, Chief Chemist*, The Sanitary District of Chicago, 910 So. Michigan Ave., Chicago, 111.

Board oj Control

■ 11.

G. B a ity , Chapel H ill, N . C.

A. S. Be d e l l, Albany, N . Y.

Earl H . Ben e d ic t, Hobart, Okla.

Al b e r t E . Be r r y, Toronto, Canada E . B . Be s s e l ie v r e, Buenos Aires, Argentina A. C. Be y e r, San Francisco, Cal.

Ea r n est Bo yc e, Lawrence, Kansas Lloyd K . Cl a r k, Bismarck, N . D.

Ar t h u r A. Cl a y, New York, N . Y.

John W . Cu n n in g h a m, Portland. Ore.

N . G. Damoose, Battle Creek, Mich.

H. J . Da r c ey, Oklahoma City, Okla.

Ciia s. A. Da v is, Denver, Col.

W . W . DeBerard, Chicago, 111.

V. M . Eh l e r s, Austin, Texas E. F. Eld r id c e, East Lansing, Mich.

C. A. Em erso n, New York, N . Y . L. H. En s l o w, New York, N . Y . J . A. Fa r m e r, Worthing, England J . L. Fe r e b e e, Milwaukee, Wis.

Pa u l S. Fox, Sante Fe, New Mexico W . F. Fr e e b o r n, Hampton-on-Thames, England Gil b e r t R. Fr it h, Atlanta, Ga.

Jo h n H . Ga r n e r. Wakefield. England F. We l l in g t o n Gtlcreas. Albany, N . Y . Harry R. Ha l l, Hyattsville, Md.

Ju l io Vet.a Hu erc o, Buenos Aires, Arg.

Ch a r l e s G. Hyd e, Berkeley, Calif.

W . Scott Jo h n so n, Jefferson City, Mo.

Fr a n k Woodbury Jo n es, Cleveland, Ohio W . I. Leonard, Boise, Idaho

Ma x Le v in e, Ames, Iowa W . S. Ma h l ie, Fort Worth, Texas F. J . Ma ie r, New York, N . Y.

Ph il J . Ma r t in, Jr., Tucson, Ariz.

C. D. McGu ir e, Columbus, Ohio A. P. Mil l e r, New York, N . Y.

H. E. Mo ses, Harrisburg, Pa.

N. L. Nu s s b a u m e r, Buffalo, N . Y . Wm. J . Orchard, Newark, N . J.

Ro bert Pe a r t, Sterling, Kan.

Wm. M. Pia t t, Durham, N . C.

W . H. Rie h l, Stratford, Canada Wil l e m Ru d o lfs, New Brunswick, *N. J.

George S. Ru s s e l l, St. Louis, M o .' Bern ard Sc h il l e r, Yuma, Ariz.

Le w is Sim o n to n, Griffin, Ga.

Richard C. Sm it h, Glen Ridge, N . J.

H. W . St r e e t e r, Cincinnati, Ohio W . W . To w n e, Pierre, S. D.

L. W . Van Kl e e c k, Hartford, Conn.

Ea r l e L . Wa t er m a n, Iowa City, Iowa Ab e l Wo lm a n, Baltimore, Md.

S E W A G E W O R K S J O U R N A L

R EG. U. 8. PAT. orr.

A Bimonthly Journal devoted to the advancement of fundamental and practical knowledge concerning the nature, collection, treatment and disposal of sewage and industrial wastes, and the design, construction, operation and manage­

ment of sewage works.

Publication Office: Prince and Lemon Sts., Lancaster, Pa.

Editorial Office: 910 So. Michigan Ave., Chicago, 111.

Subscription Price :,

Members of Local Sewage Works Associations affiliated with the Federation, $1.50 per year.

Non-members: Total fee $3.00, which includes subscription at $2.00 and service information fee of $1.00:

Canada, $3.50 per year; other countries, $4.00 per year.

Foreign Subscriptions must be accompanied by International Money Order.

Single copies: United States, $1.00 each; Foreign, $1.25 each.

Manuscript may be sent to the Editor, F. W . Mohlman, 910 So. Michigan Ave., Chicago, 111., for acceptance or rejection subject to the provisions of the Federation constitution.

S u b s c r ip t io n , ad vertisin g : co p y an d ad d re ss changres sh ou ld be sent to the B u s in e s s M a n ag e r's Office a t L a n c a s te r , P a ., o r a t 654 M a d is o n A ve., N e w Y o r k , N . Y .

No claims will be allowed for copies of Journals lost in the mails unless such claims are received within sixty (60) days of the date of issue and no claims will be allowed for issues lost as a result of insufficient notice of change of address. “ Missing from files ” cannot be accepted as the reason for honoring a claim.

Entered as second-class matter. M ay 7,-1934, at the post office at Lancaster, Pa., under the Act of March 3.

»879. _

'T / D f a y , - A D O R R C L A R I F I E R f

Z J n the clash of competition— in the welter of conflicting sales presentations clamoring for a believer— minor differences in design, shape an d appearance often tend to obliterate the real differences upon which performance depends.

This ad is a simple, direct statement on w h a t w e believe the Dorr Clarifier h a s that other types h a v e n o t— reasons w h y w e think it deserves, on its record, your preferential consideration.

► Higher Removals

Higher removal of suspended solids

— especially on raw sewage where the removal is about 20 percent higher.

► Thicker Sludge

A heavier, denser sludge, containing a greater percent solids—especially on activated sludge where the solid content is about twice as great.

► N o Disturbance of Sludge Bed Sludge is plowed gently toward cen­

tral discharge hopper with no tend­

ency to be lifted and thrown back into suspension at the end of the raking stroke.

► Better S c u m Collection

A more positive type of mechanical skimmer that, at each revolution, removes float and scum.

► N o Submerged Bearings

All metal to metal wearing parts above the water level, handy for in­

spection and lubrication.

► MoreUniform Feed, Distribution and Overflow Conditions

Central, sub-surface feeding without eddy currents or variable baffle efTects—Radial outward distribution

—Overflow across a continuous pe­

ripheral weir of maximum length, equidistant at all points from the point of feed.

► If a machine possessing these advantages appeals to you, write for our 40 page bulletin “ Sedimentation” describing the complete line of Dorr Clarifiers.

THE DORR COMPANY, INC. • ENGINEERS

5 7 0 L E X I N G T O N A V E . • N E W Y O R K

ATLANTA • T O R O N T O • C H I C A G O • DE N V E R • LOS A N G ELES

S E W A G E W O R K S J O U R N A L

F I L T R A T I O N E Q U I P M E N T C O R P .

10 East 40th Street Sales Office N e w York, N. Y.

COARSE SCREENS • AUTOMATIC MAGNETITE FILTERS • CONKEY VACUUM FILTERS THE AUTOMATIC MAGNETITE FILTER IS MARKETED EXCLUSIVELY BY THE DORR COMPANY, INC.

A P P L I C A T I O N

In Plain Sedimentation Less settling capacity re­

quired and a

40

per cent im­

provement in effluent.

In Chemical Precipitation

50

per cent less chemical consumption; less time for coagulation and settling.

In Activated Sludge

Less settling and aeration tank capacity; less c o m ­ pressed air.

In Trickling Filters

If ahead, less primary settling tank capacity. If behind, less h umus tank capacity.

A UTOMATIC M agnetite F ilters h ave dem on- C - ' * - strated their value as important step s in all the com m only u sed p rocesses of sew age treatm ent.

Under all conditions they polished plant effluents to a uniform degree and rem oved the finest solid s at a lower cost per ton than any other p iece of equip­

m en t operating over th e sam e range.

T he Automatic M agn etite Filter con sists of a 3 inch layer of carefully sized m agnetic iron ore, sup­

ported by a non-corrosive screen , and agitated by a m oving solenoid w hich periodically lifts and releases a narrow strip of ore. A counter-flow of w ash w ater, introduced as th e layer is lifted, carries off the fine particles caught by the bed and renew s the life of the filter m edium .

W rite for your copy of the Autom atic M agn etite Filter B ulletin.

PLRII1 S E D i m E t l T R T I O I l C H E m i C R L P R E C I P I T R T I 0 I 1

H m U H T E D S L U D G E £ T

T R I C K L I R G F I L T E R E F F L U E R T S

U I R T E R P U R I F I C R T I O n Ë f

2. Close up oj mag­

netic bed cleaning element

1. Magnetite Filler installed integral with round clarifier tank

u s e nuTomnTic irrg iie tite filte r s

« ï S S E E « 1

b e T t e r

C H E W \ C ^ S

Send for this Folder on

R E X S L O - M I X E R S I

¡anitatioh

J u s t off t h e press, this brief, concise folder tells the w h o l e story of R e x Slo- M i x e r s ’ m a n y n e w a d v a n t a g e s for use in multi-stage flocculation! If y o u are o p ­ erating a flocculation process or thinking of installing one, h e r e ’s th e latest n e w s o n the n e w e s t m e t h o d for providing the right turbul e n c e for m a x i m u m floe for­

m a t i o n . S e n d for y o u r c o p y n o w !

A s k a b o u t R e x S l u d g e Collectors ! A t the s a m e time, as k for y o u r c o p y of

the books, “ R e x C o n v e y o r S l u d g e C o l ­ lectors” a n d “ R e x T o w - B r o S l u d g e R e ­ m o v e r s ” — w h i c h describe in detail the design a n d application of R e x sludge- reinoving e q u i p m e n t in s e w a g e a n d w a ter t r e a t m e n t p l a n t s the c o u n t r y over!

D o n ’t m o d e r n i z e a n y plant— or design a n e w o n e — w i t h o u t learning a b o u t the n e w efficiency y o u can. expect w i t h R e x s a n i t a t i o n e q u i p m e n t ! A d d r e s s t h e C h a i n Belt C o m p a n y , 1606 W . B r u c e St., M i l w a u k e e , Wisconsin.

C H A I N B E L T C O M P A N Y o f M i l w a u k e e

These small stations, dotted around Wayne County, Michigan, are important links in a sewage disposal system. Housing pumps and primary settling tanks, they are automatic in operation and unattended, thanks to dependable equipment.

With an eye to making these buildings equally self- sufficient, Aluminum windows and some Aluminum doors were installed. They need no protective coatings of paint to preserve them. There's no rusting or rotting to require expensive replacements of parts. They are weather-tight and secure, yet are always easy to open and close.

They add to the attractiveness of these buildings.

Aluminum paint, adding its “coat of metal protec­

tion” to equipment and other metals, likewise helps to lengthen the time between visits of maintenance men.

Small plant or large, you’ll find these Alcoa Alumi­

num products helping to effect similar economies in operation and maintenance.

Al u m in u m Co m p a n yo f Am e r ic a, 2111 Gulf Build­

ing, Pittsburgh, Pennsylvania.

fense COWES first

\ T i ï r J *

ALCOA ALUMINUM

S E W A G E W O R K S J O U R N A L

V A L V E S A N D G A T E S

x 7' Table 6 Sluice Gate A djustable Side Wedges,

R ising S tem Type

C h a p m a n

STANDARDIZED SLUICE GATES

C h a p m a n S l u i c e G a t e s a r e o u t s t a n d i n g in all fields o f a p p l i c a t i o n . E v e r y g a t e is b a c k e d b y a h e r i t a g e o f s e v e n t y - f i v e y e a r s o f s u c c e s s f u l e x p e r i e n c e in sluice g a t e d e s i g n a n d m a n u f a c ­ ture. F r o m this rich e x p e r i e n c e , C h a p m a n h a s d e v e l o p e d s t a n d a r d i z e d lines e m b r a c i n g a r a n g e o f t y p e s a n d sizes t o m e e t all u s u a l c o n d i t i o n s , a t s u b s t a n t i a l s a v i n g s in c o s t a n d t i m e o f d e ­ livery. I n t e r c h a n g e a b l e p a r t s also facilitate installation a n d r e d u c e c o s t o f r e p a i r s o r r e ­ p l a c e m e n t s in t h e field. C h e c k y o u r s p ec if ic a­

ti o n s w i t h C h a p m a n ’s S l u i c e G a t e H a n d b o o k . C o p y o n r e q u e s t .

C h a p m a n

Automatic Cone Valves M otor Units & Floorstands

For the electrical operation of gate valves and sluice gates, the C h a p ­ m a n M o t o r Unit and M o t o r O p e r ­ ated Floorstand will be

found highly efficient and dependable. T h e y are rugged and extremely sim­

ple, and m a y be operated at the unit or by remote control. Seating to a n y

predetermined tightness

is controlled by the C h a p ­ m a n L i m i t S w itc h , elimi­

nating all possibility of jamming.

M o to r O perated Flo o rstan d C u t- A w ay V ie w

A u to m a tic C o ne V alve

C h a p m a n Automatic C o n e Valves are ideally suited for a n u m b e r of important uses in sewage treatment, d u e to their smooth waterway and positive operation.

R e c o m m e n d e d for:

Se w a g e p u m p dis­

charge check'valves;

Control of sludge

c h a m b e r levels; Quick

operating for grit

chambers; Air blower checks on activated sludge.

T he C h a p m a n V a l v e

INDIAN ORCHARD,

F O R S E W A G E W O R K S C h a p m a n

IRON BODY GATE VALVES

C h a p m a n is w e l l e q u i p p e d to m e e t all n e e d s of t h e s e w a g e field for v a l v e e q u i p m e n t o f e v e r y t y p e . W i d e u s e o f C h a p m a n v a l v e s in this field is g o o d e v i d e n c e o f t h e q u a l i t y a n d s e r v i c e w h i c h m a y b e e x p e c t e d o f all C h a p m a n p r o d ­ ucts. C h a p m a n I r o n B o d y G a t e V a l v e s h a v e a l o n g a n d e n v i a b l e r e c o r d in s e w a g e a p p l i c a t i o n s . T h e s t a n d a r d i z e d lines i n c l u d e all t y p e s a n d sizes t o m e e t e v e r y c o n c e i v a b l e n e e d . S e l e c t i o n f r o m C h a p m a n ’s s t a n d a r d i z e d lines m e a n s t h e b e s t v a l v e w h i c h c a n b e p r o d u c e d for t h e s e r v i c e i n t e n d e d , w i t h m a x i m u m s e r v i c e a t m i n i m u m

Typical Iron Body Gate Valve, ,

Bronze M ounted, Solid Wedge, COSt.

Rising S tem , Flanged Ends

TILTING DISC CHECKS

T h e s e c h e c k v a l v e s , u n i q u e in d e s i g n a n d o p e r a t i o n , a r e e s p e c i a l l y a d a p t e d t o v a r i ­ o u s a p p l i c a t i o n s in t h e s e w a g e w o r k s field. M a n y o f t h e o b j e c t i o n a b l e c h a r a c ­ teristics o f c o n v e n t i o n a l t y p e s w i n g c h e c k s h a v e b e e n o v e r c o m e in t h e T i l t i n g D i s c C h e c k , d u e t o t h e b e l l - c r a n k a c t i o n of t h e d i s c a n d t h e s t r e a m l i n e d w a t e r ­ w a y . S l a m m i n g is e l i m i n a t e d . E x c e s s i v e , w e a r o f m o v i n g p a r t s a n d friction losses a r e r e d u c e d t o a m i n i m u m . T h e v a l v e

closes d r o p tight, a n d is h i g h l y efficient * P ,al!inanni!r.0!1 B ™ y

, r ° J N on-Slam T iltin g Disc

a n d e c o n o m i c a l . Check Valve

M a n u f a c t u r in g C o

MASSACHUSETTS

MOTORIZED- SPEED REDUCER

BUCKET KNOCKER'

SHOCK >

ABSORBER/^

WIPER FIXED

DIFFUSERS BAFFLE ADJUSTING SCREWS

--- PERFORATED BUCKETS :reenbarswithrake

ADJUSTABLE, STEEL A .RAFFLES ff

EFFLUENT:

• R e m o v e grit at the earliest possible stage in the treatment of sewage, or it will cause trouble all along the line— in excessive w e a r of pu m p s , clogging of valves and siphons, etc. Link-Belt, drawing on ex­

tensive experience, r e c o m m e n d s the T R I T O R , which is a combination of screen and grit chamber, for small and m e d i u m size plants, and the St r a i g h t l i n e

Grit Collector and W a s h e r for larger plants. This latter unit removes grit and similar detritus from the c h a mber and discharges with a m i n i m u m of organic material and moisture.

Because it is designed and constructed to keep operating costs at a m i n i m u m , with efficiency and flexibility to m e e t varying conditions, Link-Belt equipment is preferred b y m a n y progressive c o m ­ munities everywhere.

Link-Belt T R I T O R Screen, which combines the functions of a mechanically-cleaned bar screen and grit chamber.

W R I T E F O R T H I S L i t e r a t u r e

F o l d e r N o . S W J - 1942 c o v e rin g the S T R A I G H T L I N E G r i t C o lle cto r and W asher, and Folder N o . SWJ-1587 on the S T R A I G H T L I N E B a r S c r e e n , a n d T R I T O R Screen and G r it Chamber.

L I N K - B E L T W A T E R and S E W A G E T R E A T M E N T P L A N T E Q U I P M E N T I N C L U D E S : S T R A I G H T L I N E M echanicatlv Cleaned B a r Screens, T rito r Screens, S T R A I G H T L I N E G r it Collectors and Washers, Elevated Diffusers, S T R A I G H T L I N E and C I R C U L I N E Sludge Collectors for P rim a ry and Secondary Tanks, Bio-Filtration System for Treating Sewage, S T R A I G H T L I N E M isers for Flocculation Tanks, S T R A I G H T L I N E Scum Breakers for Digestion Tanks, T raveling W ater-Intak e Screens, Ind ustrial W aste Screens, Roto-Louvre D ryers for sludge and other wet materials, P . I. V . Gear Variable Speed D riv e for Pum ps, and a complete line of elevating, convey­

ing and power transm itting equipment.

Specialists in the Manufacture o f Equipment for Water and Sewage 'Treatment Plants

P H I L A D E L P H I A C H IC A G O L O S A N G E L E S C L E V E L A N D

2045 W . H u nting P a r k A ve. 300 W . Pershing R o ad 361 S. Anderson St. 548 Rockefeller BIdg.

A tla n ta. .Baltim ore. .Boston. .Buffalo. .D allas. .D enver. .D e tro it. .Grand R ap id s. .Houston. .Huntington, W . V a .. .Indianapolis Kansas C ity , M o .. .Louisville. .N ew Orleans. .N e w Y o rk . .Oakland, C alif.. .Pittsburgh. .Portland, O re ...S a lt L ak e C it y . .Seattle

S t. Louis. .S t. P a u l. .W ilkes-Barre

I n C anada—Lin k - B e lt Lim ite d — Toronto Pla n t; M ontreal; Vancouver; Swastika

Shovel-Draeline-Crane D ivision— Lin k - B e lt Speeder Corp., Chicago and Cedar R ap id s 83m a

U A f f C - B £ L T

S C R E E N S » C O L L E C T O R S • A E R A T O R S • G R I T C H A M B E R S • M I X E R S

S e c t i o n L i n k - B e l S T R A I G H T ­ L I N E G r i t Collector and W asher show­

ing washing and de- watering screw.

Lin k - B e lt S T R A I G H T ­ L I N E G rit C ol­

lectors and Washers in the fore­

ground. Close-up of Link-Belt S T R A I G H T L I N E

G rit C ollector. N o te flights set a t an angle w ith direction of travel, which keep settled grit continually turning over, freeing lig h te r p articles of organic matter.

S E W A G E W O R K S J O U R N A L !)

C IR C LEV ILLE, 0. REPORTS EX C EP T IO N A L R ESU LT S

In Sewage Clarification With General Chemical Aluminum Sulfate

Supt. Ervin F. Leist has made an enviable record in the operation of his plant at Circleville, Ohio, in spite of an unusually complex raw sewage problem. At this plant domestic sewage is mixed with industrial wastes from two can­

ning factories, a broom factory, a milk plant, several small dairies, two soy bean plants and a stock feed mill.

Using for coagulation an average dose of 710 pounds of General Chemical Aluminum Sulfate per million gallons of sewage, Supt. Leist has obtained an average B.O.D. reduction of 70%

and a maximum reduction of 88%. Reduction in suspended solids has ranged up to 98.5%.*

As in many other successfully operated plants, Circleville uses General Chemical Aluminum Sulfate because:

1. It is simple to apply, clean, easy to handle.

2. Requires only simple, low cost equipment for application.

3. It is a year-round coagulant.

4. No other chemical is needed to complete the reaction. There is no need for exact propor­

tioning of two or more chemicals.

5. It is capable of producing a clear, sparkling effluent.

General Chemical Company is pleased to ex­

tend its cooperation to cities, townships and consulting engineers having sewage plant in­

stallation problems.

♦Fiirurea from Sewage Anrk» Enjrln., July, 1940

Your inquiries are cordially solicited. Write to

E N E R A L C H E M I C A L C O M P A N Y 40 R E C T O R STREET, N E W Y O R K , N. Y.

Sales Off if et: Atlanta • Baltimore • Boston • Buffalo • Charlotte (N, C.) • Chicago Cleveland • Denver • Houston • Kansas City • Milwaukee • Minneapolis Newark (X. J.) • New York • Philadelphia • Pittsburgh • Providence tit. I.)

St. Louis • Utica (N. Y.)

Pacific Coast Sales Offices: San Francisco • Los Angeles Pacific Sorthtcest Sales Offices: Wenatchee (Wash.) * Yakima (Wash.) In Canada: The Nichols Chemical Company. Limited • Montreal • Toronto • Vancouver

SHALLOWER

T R E N C H E S

C O S T S

SMALLER

P I P E

FEWER

J O I N T S

I N F I L T R A T I O N

LOWER

M A I N T E N A N C E C O S T S TRANSITE'S LONG LENGTHS facilitate laylnft pipe to

accurate ftrades, speed up installation and reduce the number of joints In the line.

A 5 - P O IN T S A V I N G I N S E W E R - L IN E

II Johns-M anville TRANSITE PIPE

TH E M O D E R N M A T E R I A L F O R S E W E R A N D W A T E R L IN E S

L

OOKING for lasting sewer-line sav- U ings? C h e c k the advantages of J - M Transite— the asbestos-cement sewer pipe. Y o u ’ll see h o w this m o d e r n material provides important savings on all the above points.

In municipal sewer systems, Trans­

ited high flow coefficient, tight joints, corrosion resistance a n d u n i f o r m strength are establishing a n e w stand­

ard for efficient, economical service.

T h e facts about J - M Transite Pipe are interesting an d convincing. Y o u should have full details before plan­

ning n e w sewer lines or modernizing old ones. Write for the Transite Sewer Pipe Brochure, T R - 2 1 A , to Johns- Manville, 22 E. 40th St., N. Y., N. Y.

W R I T E F O R Y O U R FREE C O P Y O F THIS N E W B R O C H U R E

S E W A G E W O R K S J O U R N A L

Soundest STA RTIN G PO IN T for Public Works Layouts. . .

I n s t r u m e n t a t i o n b y t h e O r i g i n a t o r s o t M o d e r n P r o c e s s C o n t r o l !

S e w a g e plant a n d water works layouts no longer c a n be based on cut-and-dried standards of a few years ago. Today, the operation of such plants is a n exact process, requiring the s a m e a d v a n c e d in­

strumentation as a n industrial process.

That's w h y m o r e a n d m o r e engi­

neers n o w consult F o x b o r o for assistance in d e v e l o p i n g m o r e efficient plant layouts. F o x b o r o engineers w e r e earliest pioneers of m o d e r n process control instru­

ments, a n d the originators of m a n y important types, such as flow con­

trollers, recording control instru­

ments a n d throttling controllers with a u t omatic reset. Through

long experience in instrumenting processes in industry as well as public works, they are uniquely equipped to help you.

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N E I T H E R ca se y o u g e t t h e b e n e fit o f N o r t o n e x p e r ie n c e — o v e r f i f t y y e a rs i n t h e m a n u f a c t u r e o f c e r a m ic p r o d u c t s , o v e r f if t e e n i n t h e p r o d u c t io n o f p o r o u s m e d iu m s f o r se w a g e d is p o s a l p la n t s . T h i s a c c u m u la t e d e x p e rie n c e , b o t h e n g in e e r ­ in g a n d m a n u f a c t u r in g , h a s r e s u lt c d a n p la t e s a n d t u b e s t h a t a r e o u t s t a n d in g l y p o p u l a r b e c a u s e o f t h e ir u n i f o r m a i r d i s ­ t r i b u t i o n , lo w w e t p r e s s u r e lo ss , h i g h s t r e n g t h a n d c h e m ic a l s t a b ilit y .

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f o r s e w e r s a n d s e w a g e t r e a t m e n t p l a n t s S. Cant Iron Pipe replace» another pipe material when »ewer flow main is converted to a pressure line

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r e s s u r e s c a n b e safely m a i n t a i n e d in a cast i r o n s e w e r . I n t h e i n ­ stallation illustrated cast i r o n p i p e is b e i n g laid f o r a p r e s s u r e line.

U . S. C a s t I r o n P i p e is available in sizes f r o m 3 to 8 4 i n c h e s i n 12-foot, 1 6 - f o o t a n d 1 8 -f oo t lengths. U . S. S u p e r - d e L a v a u d ce ntrifugally cast i r o n p i p e is m a d e i n 3 to 2 4 - i n c h sizes; U . S. Pi t-Cast P i p e i n sizes f r o m 3 to 8 4 inches. S t o c k s o f p i p e a n d s t a n d a r d fittings a r e c a r r i e d at 1 4 s h i p p i n g p o i n t s fo r q u i c k service.

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L U B R I C A T E D P L U G V A L V E S

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Bulletin 1031 gives complete specifications

S e w a g e W o r k s J o u r n a l P âflUOÎEïS H

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\ Q liw \ c i3 r F e d e r a t i o n of S e w a g e W o r k s As so ci a t i o n s Published by

' Lancaster, Pa.

Copyright, 1941, by Federation of Sewage Works Associations

V o l . X I I I J a n u a r y , 19 41 N o . 1

S e w a g e Research:

Studies of Sewage Purification. XIV . The Role of Sphaerotilus N atans in Activated

Sludge Bulking. By C. C. Ru c h h o f t a n d Jo h n F. Ka c i i m a r, Jr... 3

Discussion by H. He u k e l e k i a na n d R. S. In g o l s... 32

Reply to the Discussion by C. C. R u c h h o f t ... 37

Second Annual Convention, N e w York City, Oct. 9-11, 1 9 4 1 ... 38

Activated Sludge Bulking. B y H. H e u k e l e k i a n ... 39

Graphical Analysis of the Oxygen Sag. By W . E. Ho w l a n d a n d F. Fa r r... 43

Electrolysis at Terminal Island. By G. A. Pa r k f.s ... ... 48

Discussion by R. E. Po m e r o y... 59

Self-Purification of Sewhge. By II. He u k e l e k i a n ... ,... 61

Plant Operation: Sewage Flows and Composition Affecting Treatment. By A. M. Ra w n ... 66

Mechanical Equipment in Sewage Treatment. By Ll o y d M. Jo h n s o n... 73

Discussion by Ch a r l e s Gi l m a n Hy d e... ...:... ;... S6 Licensing Sewage Plant Operators. By Ch a r l e s C. Ag a r... 89

Discussion of Paper by Frank W o o db u ry Jones on “ Progress in Conditioning Sludge for Dewatering. ’’ By Ha r r y* A. Fa bf.r ... 101

Industrial Wastes: Recent Trade Waste Disposal Methods. By E. F. El d r i d g e ... 105

Experimental Treatment of Citrus Cannery Effluent in Florida. By Ha r r y IV. Vo n Lo e s e c k e... 115

Operators’ Reports and Suggestions: Operation of the Massillon, Ohio, Sewage Treatment Plant for the Year 1939. By R. F. Sn y d e r ... 132

Salient Features of the Sewage Treatment W or k s at Lima, Ohio. ByE. E. Sm i t h. .. 140

Uuder Your Glass Table Top. By W . D. Ha t f i e d... 142

The Comminution of Sewage Solids. By Phil ip F. Mo r g a n ... 145

Editorial: Books on Sewage Disposal ... 151

Proceedings of Local Associations:

California Sewage Works Association ..

New England Servage Works Association

153 155

Canadian Institute on Sewage and Sanitation... 158 South Dakota Water and Sewage Works Conference... 159 Georgia Water and Sewage Association... 161 Review s and Abstracts:

Modern Sanitation in Great Britain. By D. M. Watson ... 164 The Hydraulic Problem Concerning the Design of Sewage Storage Tanks and Sea-

Outfalls. By J. R. Raymond ... 165 The Deterioration of Concrete in Contact with Sewage. By S. S. Mo r r is... 165 The Influence of Oxygen Content on the Biochemical Oxygen Demand, Self-Purification

of Water and Activated Sludge. By Ka r l Vi e i i l... 165 Investigations on Percolating Filters. III. B y H. W i l s o n andE. J. H a m l i n 167 Ohio Conference on Sewage Treatment, Thirteenth Annual Report ... 168 The Biofiltration Process of Sewage Treatment. By A. J . Fis c h e r and R. B.

Tho m pso n ... 176 Trend of Practice in Sewage Treatment and Sludge Disposal at Recent Large Plants.

B y A l m o n L. Fa l e s ... 180 Rectangular Tanks. By II. D. Th a t c h e r... 181 Book Review s ... 182

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traatmant plant balng inatallad In tWa city. Draaaar jointa ara also being uaad on dlgaatar colla and othar inalda piping.

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C ast Iro n p ip e Is m ad e In d iam eters fro m l J i to 84 Inches.

THE CAST IRON PIPE RESEARCH ASSOCIATION. THOMAS F. WOLFE. RESEARCH ENGINEER.

1015 PEOPLES GAS BUILDING. CHICAGO, ILLINOIS

3 6 - in c h c a s t i r o n p i p e b e in g i n s t a l l e d b y C e n t r a l D e la w a r e C o u n t y ( P a . ) A u t h o r i t y f o r a n o u t f a l l s e w e r

i r o n p i p e p la y s a n im p o r t a n t p a r t i n a v a s t p r o g r a m o f s e w a g e w o r k s c o n ­ s t r u c t io n . M o r e t h a n 9 0 % o f t h e p i p e u s e d i n s e w a g e t r e a t m e n t p la n t s is c a s t i r o n p i p e a n d t h e t r e n d to c a s t i r o n s e w e rs is m o r e m a r k e d e a c h y e a r .

S e w a g e R e s e a r c h

S T U D I E S O F S E W A G E P U R I F I C A T I O N . X I V . T H E R O L E O F S P H A E R O T I L U S N A T A N S I N

A C T I V A T E D S L U D G E B U L K I N G *

B y C . C. Ru c i i h o f t a n d Jo h n F . Ka c h m a r

Principal Chemist and Jr. Chemist, U. S. Public Health Service, Stream Pollution

i. - Investigations, Cincinnati, Ohio

T h e b u l k i n g o f a c t i v a t e d s l u d g e lias r e c e i v e d t h e a t t e n t i o n o f s a n i ­ t a r y e n g i n e e r s a n d c h e m i s t s e v e r since t h e d e v e l o p m e n t o f t h e p r o c e s s to l a r g e scale o p e r a t i o n . B u l k i n g h a s b e e n c o n s i d e r e d t h e re su lt of s e v e r a l different ca us es . I n a r e c e n t excellent p a p e r I i e u k e l e k i a n a n d I n g o l s 1 d i v i d e b u l k i n g into t w o g e n e r a l c l a s s e s : c a r b o h y d r a t e b u l k i n g a n d s e w a g e b u l k i n g . T h e y s t u d i e d s e v e n f a c t o r s t h a t w e r e i n v o l v e d , i n c l u d i n g o x y g e n s u p p l y , f o o d c o n c e n t r a t i o n , s l u d g e c o n c e n t r a t i o n , s l u d g e condition, c a r b o n to n i t r o g e n ratio, t e m p e r a t u r e a n d nitrates.

B u l k i n g , t h e y said, w a s i n d u c e d b y a n e x c e s s i v e d e v e l o p m e n t o f s l u d g e o r c e r t a i n o r g a n i s m s c o m p r i s i n g t h e s l ud ge , d u e to t h e i m p r o p e r b a l ­ a n c e o f f o o d in relation to sl ud ge . T h e s e a u t h o r s s t r e s s e d a e r a t i o n r a t e a s a n i m p o r t a n t f a c t o r i n this p h e n o m e n o n .

O n e v a r i e t y o f b u l k i n g is c o m m o n l y a s s o c i a t e d w i t h e x c e s s i v e g r o w t h s o f S p l i a e r o t i l u s n a t a n s W h e n this t y p e of b u l k i n g o c c u r s c a r ­ b o h y d r a t e s a r e o f t e n f o u n d in t h e s e w a g e influent. L a c k e y a n d W a t - tie,a in a p r e v i o u s p a p e r o f this series, r e v i e w e d i n s t a n c e s o f a c t i v a t e d s l u d g e b u l k i n g in w h i c h S p l i a e r o t i l u s n a t a n s w a s c o n s i d e r e d t h e c a u s a ­ tive a g e n t , a n d p r e s e n t e d t h e b i o l o g y o f this o r g a n i s m . T h e limits o f n u t r i e n t e l e m e n t s requ is it e f o r its g r o w t h w e r e d e t e r m i n e d , a n d in a n e x t e n s i v e s e a r c h n o s u b s t a n c e w a s f o u n d , c o m m o n o r a p t to o c c u r in seAvage, A vhich s t i m u l a t e d t h e o r g a n i s m to e x c e s s i v e g r o w t h . T h e s e i n ­ v e s t i g a t o r s f o u n d S p l i a e r o t i l u s n a t a n s to b e a strict a e r o b e . L i t t m a n 3 h a s c o n t r i b u t e d a s t u d y o f t h e c a r b o n a n d n i t r o g e n t r a n s f o r m a t i o n s o f s e A v a g e b y Spliaerotilus. H e f o u n d t h a t a c o n c e n t r a t i o n o f 7 5 7 p . p . m . o f Sp li a e r o t i l u s d o s e d w i t h sterile s e A v a g e a n d a e r a t e d , r e m o v e d a m a x i ­ m u m o f 5 6 p e r c e n t of t h e 5 - d a y B . O . D . o f t h e s e A v a g e af te r f o u r h o u r s a n d al so d e t e r m i n e d t h e c a r b o n d i o x i d e p r o d u c e d . H e c o n c l u d e d t h a t th e Sp li a e r o t i l u s s l u d g e p r o d u c e d h a d h i g h s l u d g e indices, e x e r t e d a m o d e r a t e p u r i f y i n g ac t i o n o n s e A v a g e a n d t h a t c e r t a i n t y p e s o f b u l k i n g a p p e a r e d to b e t h e result o f t h e o v e r -g r o A v th o f a c t i v a t e d s l u d g e b y t h e s e o r g a n i s m s .

T h e vieAV t h a t c a r b o h y d r a t e s a r e specific s t i m u l a n t s in i n d u c i n g b u l k i n g is qu i t e c o m m o n . I n g o l s a n d I i e u k e l e k i a n 4 e x p r e s s e d t h e v i e w

* Presented at the First Annual Convention of the Sewage A\rorks Federation, Chicago, 111., Oct. 3, 1940.

3

t h a t g l u c o s e s t i m u l a t e s S p h a e r o t i l u s n a t a n s to a g r e a t e r e x t e n t t h a n z o o g l e a l bacteria, e v e n u n d e r a e r o b i c cond it io ns . I n g o l s 5 n o t o n l y c o n s i d e r s S p h a e r o t i l u s n a t a n s a s a f a c u lt at iv e a n a e r o b e b u t c o n c l u d e s t h a t S p h a e r o t i l u s n a t a n s g r o w s m u c h m o r e r a p i d l y a s t h e o x y g e n c o n ­ te nt d e c r e a s e s . T h e p h y s i o l o g y o f b o t h S p h a e r o t i l u s n a t a n s a n d z o o g l e a l b a c t e r i a s h o u l d b e v e r y c a r e f u l l y s t u d i e d s o t h a t o u r u n d e r ­ s t a n d i n g o f t h e c a u s e s a n d c u r e f o r S p h a e r o t i l u s o v e r g r o w t h s a n d b u l k i n g difficulties will b e s o u n d . I n this p a p e r , t h e r e f o r e , w e h a v e s t u d i e d t h e g r o w t h a n d m e t a b o l i c r e s p o n s e o f S p h a e r o t i l u s n a t a n s to c a r b o h y d r a t e s u n d e r a e r o b i c a n d a n a e r o b i c co nd it io ns . W h i l e to s o m e this m a y s e e m f a r r e m o v e d f r o m t h e i m m e d i a t e p r o b l e m o f b u l k i n g , s u c h p u r e c u l t u r e i n f o r m a t i o n s e e m s i m p e r a t i v e f o r a c o m p l e t e u n d e r ­ s t a n d i n g o f t h e b u l k i n g p h e n o m e n o n . F o l l o w i n g this a series o f e x ­ p e r i m e n t s w e r e p e r f o r m e d i n w h i c h b u l k i n g w a s i n d u c e d i n a c t i v a t e d s l u d g e b y c e r t a i n f e e d i n g p r o c e d u r e s a l o n g w i t h S p h a e r o t i l u s i n o c u l a ­ tions.

I n p r e v i o u s p a p e r s o f this series,8’ 8 t h e s i m i l a r i t y o f t h e s e w a g e p u r i fi ca ti on p h e n o m e n o n b y p u r e c u l t u r e z o o g l e a l b a c t e r i a a n d b y n o r ­ m a l a c t i v a t e d s l u d g e h a s b e e n d e m o n s t r a t e d . T h e s e w a g e a n d g l u c o s e m e t a b o l i s m o f b o t h p u r e c u l t u r e z o o g l e a l s l u d g e s a n d o f p l a n t acti­

v a t e d s l u d g e s h a v e al so b e e n s t u d i e d a n d r e p o r t e d . 9’10 It w a s d e c i d e d to s t u d y S p h a e r o t i l u s n a t a n s s l u d g e s i n a s i m i l a r m a n n e r to d e t e r m i n e a n y d i f f e r e n c e s in t h e m e t a b o l i s m o f this o r g a n i s m , a n d to elucidate, if possible, t h e f a c t o r s i n v o l v e d i n s l u d g e b u l k i n g a n d t h e a c c o m p a n y i n g o v e r g r o w t h o f t h e z o o g l e a l b a c t e r i a b y S p h a e r o t i l u s .

Pr e l i m i n a r y Ex p e r i m e n t s

A n u m b e r o f e a r l y e x p e r i m e n t s w e r e c a r r i e d o u t i n c o o p e r a t i o n w i t h t h e biological l a b o r a t o r y u p o n t h e g r o w t h r e q u i r e m e n t s o f S p h a e r o t i l u s n a t a n s . T h e s e e x p e r i m e n t s s h o w e d t h a t t h e f u n g u s h a d difficulty u s i n g g l u c o s e in a m e d i u m c o n t a i n i n g o n l y g l u c o s e a n d m i n e r a l salts. I f n i ­ t r o g e n o u s m a t e r i a l s s u c h a s p e p t o n e , u r e a , m a n y a m i n o acids, o r sterile d o m e s t i c o r s y n t h e t i c s e w a g e w e r e a d d e d t h e r a t e o f g r o w t h a n d g l u ­ c o s e utilization w a s g r e a t l y acce le ra te d. I n o n e s u c h e x p e r i m e n t in a m e d i u m c o n t a i n i n g g l u c o s e a n d m i n e r a l salts, o n l y 4 1 p . p . m . o u t o f 1 0 0 0 p.p.rn. o f g l u c o s e o r i g i n a l l y p r e s e n t , o r 4.1 p e r cent, w e r e u s e d i n 1 2 0 h o u r s b y a S p h a e r o t i l u s culture. W i t h settled s e w a g e , h o w e v e r , t h e f u n g u s w a s a b l e to act u p o n 8 0 0 to 9 0 0 p . p . m o f g l u c o s e 'within 2 4 to 4 8 h o u r s a f t e r in oc ul at io n. T h e s e e x p e r i m e n t s also i n d i c a t e d t h a t t h e g l u c o s e a t t a c k b y S p h a e r o t i l u s w a s , c u ri ou sl y, m o r e v i g o r o u s w h e n f r e s h l y i n o c u l a t e d t h a n w h e n c o n c e n t r a t i o n s o f 2 0 0 to 5 0 0 p . p . m . o f 48- to 7 2 - h o u r c u l t u r e s w e r e u s e d . It w a s al so n o t e d i n o n e e x p e r i m e n t t h a t lactic a c i d w a s p r o d u c e d . H o w e v e r , lactic a c i d w a s n o t a l w a y s p r o d u c e d i n t h e m e t a b o l i s m o f S p h a e r o t i l u s n a t a n s , a n d w h e t h e r its p r o ­ d u c t i o n is d u e to a c h a n g e i n t h e m e t a b o l i s m u n d e r c e r t a i n co nd it io ns , o r to a sp ec ia l s t r a i n w h i c h c a n n o t b e d i f f e r e n t i a t e d m o r p h o l o g i c a l l y f r o m t h e c o m m o n strains, is u n k n o w n at pr e s e n t .

Vol. 13, No. 1 STUDIES OF S E W A G E PURIFICATION. XIV 5

L a c k e y a n d W a t t l e 2 also isolated a n u m b e r o f o t h e r f u n g i h a v i n g t h e g e n e r a l m a c r o s c o p i c a p p e a r a n c e a n d char ac te ri st ic s o f S p h a e r o t i l u s . E x p e r i m e n t s w i t h p u r e c u l t u r e s o f t h r e e s u c h st r a i n s o f f u n g i i n d i c a t e d t h a t t h e s e o r g a n i s m s a t t a c k g l u c o s e in g l u c o s e - s e w a g e m e d i a at r a t e s s i m i l a r to S p h a e r o t i l u s n a t a n s .

Fir s t Ex p e r i m e n t s u p o n Ox y g e n Ut il iz a t io n

A n u m b e r o f e x p e r i m e n t s to d e t e r m i n e o x y g e n utilization r a t e s w e r e m a d e in 1 9 3 8 a n d 1939. T h e m e t h o d s e m p l o y e d i n t h e p r e v i o u s w o r k u p o n z o o g l e a l a n d p l a n t a c t i v a t e d s l u d g e s w e r e u s e d . T h r e e bottles c o n t a i n i n g e q u a l c o n c e n t r a t i o n s o f S p h a e r o t i l u s n a t a n s w e r e p r e p a r e d . T w o o f t h e s e w e r e d o s e d w i t h f r e s h n u t r i e n t m a t e r i a l a n d t h e third, c o n t a i n i n g t h e o r i g in al s u p e r n a t a n t , w a s u s e d a s a control. T h e o x y ­ g e n utilization w a s t h e n f o l l o w e d in th e c o n t r o l a n d o n e o f t h e f e d cu l­

t u r e bottles, w h i l e t h e l i q u o r in t h e s e bottles w a s a e r a t e d b y m e r c u r y p u m p s at r a t e s o f a b o u t 1.2 cu. ft. p e r h o u r . T h e S p h a e r o t i l u s n a t a n s solids a n d g l u c o s e c o n t e n t w e r e f o l l o w e d in t h e t h i r d bottle, this bottle b e i n g a e r a t e d w i t h c o m p r e s s e d air. It w a s f o u n d t h a t w h i l e this s y s ­ t e m of s t u d y h a d b e e n s a t i s f a c t o r y f o r t h e m e t a b o l i c s t u d y o f a c t i v a t e d s l u d g e a n d z o o g l e a l b a c t e r i a cultures, it w a s n o t s a t i s f a c t o r y f o r S p h a e ­ r o t i l u s n a t a n s . T h e g r o w t h a n d m e t a b o l i c r a t e s w e r e different in t h e bottles a e r a t e d b y c o m p r e s s e d air a n d b y t h e m e r c u r y p u m p , a p p a r e n t l y b e c a u s e o f di ff e r e n c e s in s o m e i m p o r t a n t f a c t o r o r f a c t o r s in t h e t w o bottles. A c o n d e n s e d s u m m a r y o f t h e results o b t a i n e d in six o f t h e s e e x p e r i m e n t s is g i v e n in T a b l e I. If t h e results in this table a r e st udied, t h e y will b e f o u n d to b e s o m e w h a t inconsistent. N e v e r t h e l e s s , a n u m -

Ta b l e I.—Glucose Removal ami Oxygen Utilization by Sphaerotilus natans Cultures

(Results obtained by simultaneous aeration in 3 bottles)

Experi­

ment No.

Initial Values After 23 Hours of Aeration of Fed

Culture Oxygen Utilized in 23 Hours of Aeration

pH Sphaerotilus natans

Solids Glucose Sphaerotilus

Solids Glucose Removed

FedBy Culture

ControlBy Culture

As Re­

sult of Food Added

P.p.m. P.p.m. P.p.m. P.p.m. P.p.m. P.p.m. P.p.m.

6 6.6 90 503 + 148 91 77 19 58

7 6.4 418 1097 + 120 527 401 152 249

8 6.0 1304 1040 +468 831 — 241 —

9 6.8 1532 1083 +334 404 390 283 107

10 6.6 1275 1053 - 2 2 9 853 325 256 69

13 6.8 153 1311 +215 173 207 — —

b e r o f in t e r e s t i n g o b s e r v a t i o n s m a y b e m a d e f r o m t h e m . First, t h e r e s e e m s to b e n o c o r r e l a t i o n b e t w e e n t h e initial q u a n t i t y , o f S p h a e r o t i l u s n a t a n s a n d t h e q u a n t i t y o f g l u c o s e a t t a c k e d o r t h e e x t e n t o f S p h a e r o ­ tilus g r o w t h d u r i n g ae ra ti on . S e c o n d , c o n s i d e r i n g t h e v e r y h i g h B . O . D . o f t h e f e e d u s e d in t h e s e e x p e r i m e n t s , t h e q u a n t i t y o f o x y g e n

utilized b y t h e f e d c u l t u r e s e e m s to b e l o w , w h i l e t h e q u a n t i t y u s e d b y t h e c o n t r o l s e e m s r a t h e r high . C o n s e q u e n t l y , t h e i n c r e m e n t o f o x y g e n w h i c h w a s u s e d a s a r e su lt o f t h e a d d i t i o n o f t h e f o o d a p p e a r s lo w.

T h i s i n c r e m e n t s e e m s to b e a r n o c o n s i s t e n t r e l a t i o n to t h e q u a n t i t y of g l u c o s e a c t e d u p o n .

It is i n t e r e s t i n g to c o m p a r e t h e q u a n t i t i e s o f o x y g e n u s e d b y o n e g r a m q u a n t i t i e s o f c o n t r o l zo o g l e a l sl u d g e , a c t i v a t e d s l u d g e a n d S p h a e ­ r o t i l u s n a t a n s s l u d g e a s s h o w n b e l o w :

Ob s e r v e d Ox y g e n Ut i l i z a t i o n Ra n g e i n M g. 0 2 p e r Gr a m,o f Co n t r o l Sl u d g e

in 24 Ho u r s

Pure Culture

Zoogleal Sludge Plant Activated

Sludge Pure Culture Sphaerotilus

natans Sludge

16.4 37.8 185

to to to

29.2 177.0 364

T h e d i f f e r e n c e s in t h e 2 4 - h o u r o x y g e n r e q u i r e m e n t s o f t h e s e t h r e e k i n d s o f c o n t r o l s l u d g e s a r e v e r y striking. T h e v e r y h i g h v a l u e s fo r S p h a e r o - t i l u s n a t a n s c a n u n d o u b t e d l y b e e x p l a i n e d b y t w o facts. T h e first is t h e m u c h h i g h e r B . O . D . o f t h e s u p e r n a t a n t r e m a i n i n g in s u c h c u l t u r e s w h e n d e v e l o p e d r a p i d l y in sterile s e w a g e g l u c o s e m e d i a , a n d t h e s e c o n d is t h e inability to r e m o v e a s l a r g e a f r a c t i o n o f t h e s u p e r n a t a n t a s e p - tically in s u c h c u l t u r e s d u e to t h e b u l k i n e s s a n d l a c k o f ability of S p h a e r o t i l u s n a t a n s to settle a n d c o m p a c t w e l l in th e a l l o w a b l e settling p e r i o d . T h e s e e x p e r i m e n t s i n d i c a t e d t h a t this m e t h o d o f s t u d y o f S p h a e r o t i l u s n a t a n s m e t a b o l i s m w a s n o t s a t i s f a c t o r y b e c a u s e o f i n t e r ­ f e r i n g f a c t o r s w h i c h r e q u i r e d investigation.

Fa c t o r s Af f e c t i n g t h e Gr o w t h a n d Me t a b o l ic Ac t iv it ie s of Sp h a e r o t i l u s n a t a n s

A c t i v a t e d s l u d g e p l a n t o p e r a t i o n efficiency is a f f e c t e d b y s u c h f a c ­ tors a s t h e r a t e o f a e ra ti on , p H , t e m p e r a t u r e a n d t h e D . O . c o n t e n t o f t h e m i x e d liquor. A t p r e s e n t t h e c o n d i t i o n s o b t a i n i n g in a n a c t i v a t e d s l u d g e t h a t f a v o r t h e r a p i d a c c u m u l a t i o n o f S p h a e r o t i l u s a n d t h e d e ­ v e l o p m e n t o f a b u l k y s l u d g e a r e n o t w e l l u n d e r s t o o d . I n f o r m a t i o n a s to t h e c o n d i t i o n s w h i c h f a v o r t h e o p t i m u m o p e r a t i o n o f t h e m e t a b o l i c p r o c e s s e s o f S p h a e r o t i l u s n a t a n s a n d c o n s e q u e n t l y t h o s e w h i c h f a v o r t h e r a p i d d e v e l o p m e n t o f S p h a e r o t i l u s w o u l d b e o f v a l u e i n d e t e r m i n i n g t h e c o n d i t i o n s u n d e r w h i c h b u l k i n g is n o t likely to occur. T h e p r e v i o u s e x p e r i m e n t s g a v e e v i d e n c e t h a t t h e a b o v e f a c t o r s also affect t h e d e ­ v e l o p m e n t o f S p h a e r o t i l u s n a t a n s . C o n s e q u e n t l y , their effect u p o n th e g r o w t h a n d m e t a b o l i c p r o c e s s e s o f p u r e c u l t u r e s o f S p h a e r o t i l u s n a t a n s w a s s t u d i e d in a series o f e x p e r i m e n t s .

Vol. 13, No. 1 STUDIES OF S E W A G E PURIFICATION. XIV 7

Ex p e r im e n t a l, Pr o c e d u r e i n a St u d y of Gr o w t h Fa cto rs

T h e m e d i u m w h i c h h a d b e e n f o u n d to c o n t a i n a m p l e q u a n t i t i e s o f all t h e n u t r i e n t m a t e r i a l s f o r S p h a e r o t i l u s n a t a n s w a s u s e d in all o f t h e s e e x p e r i m e n t s . T h i s m e d i u m c o n t a i n e d t h e f o l l o w i n g m a t e r i a l s : D e x ­ trose, 1 0 0 0 m g m . ; p e p t o n e , 6 0 0 m g m . ; m e a t extract, 2 0 0 m g m . ; u r e a , 5 0 m g m . ; N a J I P O , , 5 0 m g m . ; N a C l , 1 5 m g m . ; C a C L , 7 m g m . ; M g S C h , 5 m g m . ; K O I , 7 m g m . ; distilled w a t e r to m a k e 1 liter.

S i x t e e n liter b a t c h e s o f t h e a b o v e m e d i u m w e r e p r e p a r e d a n d si­

p h o n e d into e a c h o f five 4-liter s e r u m bottles, t h e p H a d j u s t e d to t h e d e s i r e d p o i n t a n d t h e bottles of m e d i a sterilized. A t t h e star t o f e a c h e x p e r i m e n t e a c h bottle o f m e d i u m w a s i n o c u l a t e d f r o m a t h r i v i n g 24- liour r o o m t e m p e r a t u r e c u l t u r e o f Sp li ae ro ti lu s in s i m i l a r m e d i a . T h e c u l t u r e u s e d f o r i n o c u l a t i o n c o n t a i n e d f r o m 2 6 8 to 1 3 0 0 p . p . m . o f S p l i a e ro ti lu s w h e n d e t e r m i n e d a s d r y s u s p e n d e d solids.

W h i l e all p l a n t i n g s w e r e m a d e f r o m p u r e c u l t u r e s w i t h sterile p i p e t t e s a n d t h e p r e c a u t i o n s u s e d o n z o o g l e a l c u l t u r e s to m a i n t a i n p u r e c u l t u r e s t h r o u g h o u t t h e 2 4 - h o u r a e r a t i o n p e r i o d w e r e u s e d , bacterial in fe ct io ns s o m e t i m e s o c c u r r e d . U s u a l l y a 5 0 m l . p o r t i o n o f t h e c u l t u r e w a s u s e d to i n o c u l a t e e a c h f o u r liter bottle at t h e b e g i n n i n g o f t h e e x ­ p e r i m e n t . S e v e r a l Sp liaerotilus st ra in s w e r e u s e d . A l l o f t h e m w e r e v e r y m u c h alike s o f a r a s m e t a b o l i s m w a s c o n c e r n e d e x c e p t o n e s t ra in ( S - 7 ) , w h i c h , u n l i k e t h e others, p r o d u c e d l a r g e qu a n t i t i e s o f lactic ac i d f r o m gl ucose.

Ef f e c t o f Ae r a t io n Pa te u p o n Sp h a e r o t i l u s n a t a n s Gr o w t h a n d Me t a b o l is m

B e c a u s e it h a d b e e n n o t i c e d in earlier w o r k t h a t t h e a e r a t i o n r a t e a f f e ct ed t h e g r o w t h of S p l i a e r o t i l u s n a t a n s , this f a c t o r w a s s t u d i e d first.

E x p e r i m e n t s to d e t e r m i n e w h e t h e r S p l i a e r o t i l u s n a t a n s w a s c a p a b l e o f a n a e r o b i c g r o w t h w e r e incl ud ed . T h r e e e x p e r i m e n t s w e r e r u n at r o o m t e m p e r a t u r e . F i f t e e n ra t e s o f a e r a t i o n w e r e u s e d v a r y i n g f r o m 0.00 to 11.8 cu. ft. o f air p e r h o u r p e r t h r e e liters o f culture. T h e a e r a ­ tion r a t e s w e r e m e a s u r e d at th e start a n d af t e r t h r e e to f o u r h o u r s a n d s o m e v a r i a t i o n s o v e r t h e 2 4 - h o u r p e r i o d w e r e u n a v o i d a b l e . O f t h e r a te s u s e d f o u r w e r e less t h a n 0.2 cu. ft. p e r h o u r , t h r e e in t h e r a n g e o f 0.2 to 0.5 cu. ft. p e r h o u r , t h r e e b e t w e e n 1.0 a n d 3.0 cu. ft. p e r h o u r , a n d t h r e e g r e a t e r t h a n 5.0 cu. ft. p e r h o u r .

A t t h e start a n d af t e r 2 4 h o u r s o f a e r a t i o n e x a m i n a t i o n s w e r e m a d e f o r bact er ia l infection, p H , g l u c o s e a n d S p h a e r o t i l u s s u s p e n d e d solids.

I n o n e e x p e r i m e n t total n i t r o g e n d e t e r m i n a t i o n s w e r e also m a d e . T h e d i s s o l v e d o x y g e n o f t h e a e r a t i o n m i x t u r e w a s r u n i m m e d i a t e l y at t h e e n d o f e a c h e x p e r i m e n t .

T h e a n al yt ic al results o b t a i n e d a r e g i v e n in T a b l e II. T h e s e r e ­ sults i n d i ca te t h a t m o s t st ra in s o f S p h a e r o t i l u s utilized g l u c o s e a n d p e p ­ t o n e w i t h o n l y a s m a l l d r o p in p H ( f r o m 6.9-7.1 at star t to 6.4-6.6 af te r 2 4 h o u r s ) . I n e x p e r i m e n t S - 2 3 w i t h s t r a i n S - 7 , w h i c h is t h e lactic a c i d p r o d u c i n g strain, t h e p H d r o p p e d f r o m 7.2 to 4.6 a n d a f f e ct ed t h e re-