MUNICIPAL PHOSPHORUS LOADINGS

TO LAKE ERIE

AN EVALUATION STUDY PREPARED FOR THE

GREAT LAKES WATER QUALITY BOARD

GREAT LAKES REGIONAL OFFICE INTERNATIONAL JOINT COMMISSION

DECEMBER, 1975

REVIEW NOTICE

Mention o f trade names or commercial p r o d u c t s in this

report does not constitute endorsement or recommendation for

use.

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TABLE OF CONTENTS

Page No.

PREFACE

INTRODUCTION

Study Objectives

DESCRIPTION OF WASTEWATER TREATMENT FACILITIES

Detroit, Michigan

Cleveland Easterly, Ohio

Cleveland Southerly, Ohio

Toledo, Ohio

Akron, Ohio

Wayne County (Wyandotte), Michigan

Erie, Pennsylvania

Cleveland Westerly, Ohio

Fort Wayne, Indiana

West Windsor, Ontar io

London Greenway, Ontario

Kitchener, Ontario

DATA COLLECTION AND ANALYSIS

Loading Data

Bypass Data

Analytical Methods

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8

9

9

10

10

11

11

13

13

15

15

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TABLE OF CONTENT< (Cont'd.)

Page No. "

PLANT PERFORMANCE - A COMPARATIVE srmy 17

Comparison of Actual and Targeted Loadings 19

CONCLUSIONS AND RECOMMENDATIONS 21

APPENDIX - EFFLUENT PHOSPHORUS, BOD5 AND SUSPENDED SOLIDS

CONCENTRATIONS 23

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This r epor t has been p repa red by t h e IJC Regiona l Of f i ce fo r t he Great Lakes Water Qual i ty Board, It deals with phosphorus loadings f rom municipal sources and is t h e f i r s t of a series o f r e p o r t s e v a l u a t i n g t h e t o t a l p h o s p h o r u s l o a d i n g s t o Lake Erie.

A d r a f t o f t h i s r e p o r t was p resen ted by t h e R e g i o n a l O f f i c e t o t h e Water Quality Board a t i t s Nine teenth Meet ing he ld in Det ro i t , Michigan on September 18, 1975. I t has s ince been reviewed by t h e Board. The munici- p a l i t i e s i n v o l v e d i n t h e s t u d y were a l s o a s k e d t o comment on t h e r e p o r t t h rough t he appropr i a t e Board members.

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A t i t s Six teenth Meet ing he ld in Toronto on March 5 and 6 , 1975, the Great Lakes Water Qua l i ty Board a u t h o r i z e d t h e IJC R e g i o n a l O f f i c e t o c a r r y o u t a n e v a l u a t i o n s t u d y on municipal phosphorus loadings in the Lake Erie Basin. Twelve major municipal wastewater t rea tment p lan ts in Michigan , Ohio , Indiana, Pennsylvania and Ontar io were s e l e c t e d f o r t h i s s t u d y . The combined f low f rom these twe lve t r ea tmen t p l an t s accoun t s fo r ove r 80 percent o f the t o t a l m u n i c i p a l s e w a g e f l o w i n t o Lake Erie as r epor t ed i n t h e 1974 Water Qua l i ty Board Annual Report.

R e g i o n a l O f f i c e s t a f f v i s i t e d a l l t h e t w e l v e t r e a t m e n t p l a n t s . I n some c a s e s , o f f i c i a l s f r o m t h e r e s p e c t i v e j u r i s d i c t i o n s a c c o m p a n i e d t h e IJC s t a f f . I n a l l cases, p l a n t v i s i t s were a r r a n g e d e i t h e r t h r o u g h t h e j u r i s - d i c t i o n s o r by the Reg iona l Of f i ce w i th fu l l knowledge and consen t of t h e agenc ie s . P l an t r eco rds were o b t a i n e d f r o m e i t h e r t h e p l a n t s u p e r i n t e n d e n t s o r t h e a g e n c i e s .

STUDY OBJECTIVES

The fo l lowing are the ob jec t ives o f t he s tudy :

(1) Review and assess ava i l ab le ope ra t iona l and p l an t pe r fo rmance r eco rds .

(2) Determine, on the basis of avai lable t reatment plant records, the phosphorus loading in to Lake Erie.

(3 ) Assess the adequacy of a n a l y t i c a l t e c h n i q u e s u s e d i n m e a s u r i n g p o l l u t a n t s i n g e n e r a l a n d p h o s p h o r u s i n p a r t i c u l a r .

(4) Determine i f independent sampling is requ i r ed .

(5) Assess pol lu t ion loadings f rom t rea tment p lan t bypasses and/or s torm- water overf lows.

(6) P r e s e n t a common base from which plant performance of each of t h e ma jo r p l an t s can be compared.

( 7 ) Out l ine opera t iona l p roblems assoc ia ted wi th the phosphorus removal program.

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DESCRIPTION OF WASTEWATER TREATMENT FACILITIES

The twe lve t r ea tmen t p l an t s a r e cha rac t e r i zed i n Table 1 i n terms of f low, t rea tment p rocess , phosphorus removal and s ludge handl ing fac i l i t i es a t t h e time of the s tudy . F igu re 1 shows t h e l o c a t i o n 01. each of t h e p l a n t s .

The fo l lowing pa rag raphs desc r ibe t he t r ea tmen t p l an t s beg inn ing wi.th t h e l a r g e s t o n e . A l l f l o w u n i t s are p resen ted i n m e g a l i t r e s p e r day (MR/d) followed by m i l l i o n g a l l o n s p e r day (MGD) i n p a r e n t h e s e s .

DETROIT

The D e t r o i t p l a n t i s t h e l a r g e s t w a s t e w a t e r t r e a t m e n t p l a n t i n t h e Great Lakes Basin. I t is ope ra t ed by the Detroi t Metropol i tan Water Department . Or ig ina l ly cons t ruc ted in 1940, the p lan t has s ince been expanded to p rovide t rea tment for the p resent f low of abo; l t 3230 MA/d (850 MGD). Cons t ruc t ion i s s t i l l i n p r o g r e s s .

The t r ea tmen t p rov ided cons i s t s of pr imary sedimentat ion for 2280 Ma/d (600 MGD) and pure oxygen act ivated s ludge (Unox) p r o c e s s f o r 950 MR/d (250 MGD). T h e s y s t e m a l s o h a s a e r a t i o n t a n k s f o r t r e a t i n g 570 MR/d (150 MGD) w i t h d i f f u s e d a i r a c t i v a t e d s l u d g e . However, due t o l i m i t e d c l a r i f i e r and inc ine ra t ion capac i ty , t he s econda ry t r ea tmen t sys t em is p r e s e n t l y l i m i t e d t o e i t h e r a i r o r oxygen opera t ion bu t no t bo th concurren t ly . Cons t ruc t ion of t h e s e f a c i l i t i e s is expected to be completed by October 1975. Provis ion for phosphorus removal with iron salts ( w a s t e p i c k l e l i q u o r ) commenced i n t h e s p r i n g o f 1970. Polymer feed equipment was p l a c e d i n o p e r a t i o n i n J a n u a r y 1972 which r e su l t ed i n fu r the r phosphorus r emova l du r ing t he f i rs t s i x months of 1972. In the l a t t e r part. of 1972 and during 1973, t h e r e wexL a series of mechanical problems with t h e waste p i ck le l i quor and po lymer app l i ca t ion sys t ems and t h i . s r e su l t ed i n Jery errat ic phosphorus removal during the p e r i o d . E f f l u e n t from the p lan t l d i scharges in to the Det ro i t River .

Sludge f rom the plant i s dewatered on vacuum f i l t e r s and inc inera ted . Ash i s disposed of on land. A per s i s t en t p rob lem in t he De t ro i t p l an t has been the inadequacy of the s ludge handl ing sys tem. The newly expanded f a c i l i t i e s are cu r ren t ly expe r i enc ing s t a r t -up p rob lems . So l ids i n excess of the s ludge hand l ing capac i ty a r t . r e t a ined i n t he t r ea tmen t sys t em wi th a r e s u l t a n t d e t e r i o r a t i o n i n e f f l u e n t q u a l i t y .

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PLANT

DETROIT

CLEVELANJ EASTERLY

CLEVELAND SOUrHERLTi

TOLEDO

AKRON

WYANDOTTE

ERIE

CLEVELAND WESTERLY

FORT WAYNE

WIM)SOR

LONDON

KITCHENER

Mild

1974 AVERAGE FLOW

MRId

3230 ( 850 MGD)

437 ( 115 MGD)

360 ( 95 MGD)

380 ( 100 MGD)

340 ( 90 MGD)

277 ( 73 MGD)

159 ( 42 MGD)

148 ( 39 MGD)

12 3 ( 32 MGD)

99 ( 22 MIGD)

82 ( 18 MIGD)

65 ( 14 MIGD)

megalitres per day;

TREATMENT PROCESS

Secondary for 950 MR/d (250 MGD); Primary for remaining.

Secondary

Secondary

Secondary

Secondary

Primary Secondary (Unox) in 1976

Secondary

Primary (Imhoff tanks)

Secondary with polishing pond

Primary

Secondary

Secondary

PHOSPHORUS REMOVAL FACILITY

Pickle liquor since early 1970; Polymer since January 1972.

Pickle liquor since June 1975.

Pickle liquor intermittently.

FeC13 since December 1972.

Low influent phosphorus.

FeC13 since May 1973.

FeC13 and polymer since April 1975

Iron salts (FeCl?, pickle liquor) since November 1972.

Alum since July 1973.

FeC13 intermittently since Feb. 1974; Alum since Feb. 1975.

Not necessary; P level less than 1 mg/L without direct chemical addition.

Alum since January 1974.

MIGD - million imperial gallons per day; MDG - million gallons per day

TABLE 1

SLUDGE DISPOSAL FACILITY _~I"

Vacuum filtration, incineration, Ash disposed of as solid waste.

None; sludge pumped to Cleveland Southerly.

Anaerobic digestion; vacuum filtration and and incineration; ash lagoon.

Anaerobic. digestion; vacuum filtration, land disposal for agricultural purpose at present.

Primary sludge is filtered and incinerated; activated sludge is treated with wet air oxidation.

Vacuum filtration, incineration; ash lagoon.

Sludge thickening; vacuum filtration and incineration.

Anaerobic digestion; vacuum filtration; incineration. Disposal system inadequate.

Primary sludge is anaerobically digested and lagooned.

Vacuum filtration or centrifuged; land disposal.

Air flotation; vacuum filtration and incineration; ash lagoon.

Anaerobic digestion, vacuum filtration; lagoon.

.LONDON

LAKE ERIE

J oFoRT WAYNE .AKRON

figure I: WASTE WATER TREATMENT PLANT LOCATIONS

The p lan t ?po r t s no bypass i n d ry o r w e t weather. However, t h e D e t r o i t wastewater co l l ec t ion sys t em has 76 poss ib l e ove r f low po in t s . A r e c e n t r epor t ' on an EPA demonst . ra t ion project on the monitor ing and remote control of the sewerage system has been publ ished. The r e p o r t i n c l u d e s d e t a i l e d d i scuss ion and eva lua t ion of the monitor ing and remote control equipment , i n s t a l l a t i o n d e t a i l s , t h e c o n c e p t of in -sys tem s torage , and the opera t ion of the system based on an 18-month s tudy per iod. In-system s torage of s torm- water h a s b e e n i d e n t i f i e d a s a feas ib1 .e and economica l a l te rna t ive to sewer s e p a r a t i o n ,

Expansion i s s t i l l underway a t t h e p l a n t t o i n c r e a s e t h e c a p a c i t y t o 4560 MR/d (1200 MGD).

CLEVELAND EASTERLY ___-

Cleveland Eas te r ly i s t h e L a r g e s t o f t h e t h r e e t r e a t m e n t p l a n t s i n t h e City of Cleveland operated by the Cl.eveland Regional Sewer District (CRSD). Its 1974 average f low was 437 ! a / d (115 MGD). The p l a n t was o r i g i n a l l y c o n s t r u c t e d i n t h e 1 9 3 0 ' s .

The t reatment provided is conven t iona l ac t iva t ed s ludge . Fu l l scale chemical addi t ion for phosphorus removal did not commence u n t i l J u n e of 1975. E f f luen t phosphorus concen t r a t ion f o r 1974 averaged 2 mg/R. The e f f l u e n t d i scha rges i n to Lake Erie. The p l a n t i s experiencing problems with submerged overf low weirs caused by the h igh lake l eve l .

There are no s l u d g e h a n d l i n g f a c i l i t i e s a t t h i s p l a n t . The s ludge is pumped t o the Cleve land Souther ly P lan t .

The p l a n t has faci l . i t ies fo r bypass ing raw sewage. However, on ly t he d u r a t i o n of bypass i.s recorded. For 1974, a monthly average of 290 hours of bypass was r e p o r t e d . Thc.rrc a r e no flow measurements on the bypass.

Construct ion of new headworks i s near completion.

CLEVELAND SOUTHERLY

The Sou the r ly P l an t I . L < ~ S a des ign capac i ty o f 437 MR/d (115 MGD). Its 1974 average f low was 360 MR/d (95 MGD). It was o r i g i n a l l y p l a c e d i n o p e r a t i o n i n 1 9 2 7 .

The p lan t p rovides secondary t rea tment to the incoming raw sewage and s ludge f rom Eas te r ly . The f ina l e f f luen t phosphorus concen t r a t ion ave raged about 1 mg P / k i n 1974 without the addi t ion of chemical coagulants . Pickle l i q u o r i s p r e s e n t l y br , ing added t o p r o v i d e f u r t h e r r e m o v a l .

The s ludge i s aua: .uobical ly digested, vacuum f i l t e r e d and i nc ine ra t ed . Ash is disposed of i n I n ash lagoon.

'Sewerage System Monitor.kng and Remote Control, U.S. EPA-670/2-75-020.

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T W O Inajor i n t e r c e p t o r s c a r r y i n g raw sewage and stormwater t o t h e p l a n t have overflow points upstream to the headworks. Only hours of bypass are recorded , In 1974, a monthly average o f 79 hours of raw sewage bypass was r epor t ed .

TOLEDO

The o r i g i n a l T o l e d o p l a n t c o n s i s t e d of a 266 M?./d (70 MGD) primary E a c i l i t y b u i l t i n 1932 and a 182 MR/d (48 MGD) s e c o n d a r y p r o c e s s i n s t a l l e d i n 1957. An expansion was made i n 1973 t o p rov ide s econda ry ' t r ea tmen t fo r a t o t a l f l o w of 380 MR/d (100 MGD). The volume of i n J u s t r i a l waste is est i - mated t o h e a b o u t 114 MR/d (30 MGD). The p l a n t d i s c h a r g e s d i r e c t l y to t h e Maumee River .

Chemicals have been added since l a t e 1.972 for phosphorus removal. The 1974 average e f f luent phosphorus c .oncent ra t ion was 2 . 2 mg P / & .

Sludge is a n a e r o b i c a l l y d i g e s t e d , vacuum f i l t e r e d and trucked f o r land d i s p o s a l . The p l an t has been expe r i enc ing so l id s p rob lems w i th its l i m i t e d s l u d g e h a n d l i n g f a c i l i t i e s . The i n t e r i m s o l u t i o n h a s becn t o r e t a i n the s o l i d s i n i t s a e r a t i o n t a n k s f o r as long as p r a c t i c a l . T h e d e t e r i o r a t e d e f f l u e n t q u a l i t y i s i n pa r t caused by the carryour:- of e x c e s s s o l i d s .

The t r ea tmen t p l an t bypasses raw sewage under w e t weather c .ondi t ions. The bypass f requency has been es t imated by Ohio o f f i c i a l : ; t o be less than once a month w i t h d u r a t i o n less than 8 hours. The re a r e a l so overf lows occurr ing ups t ream of the t r ea tmen t p l an t .

The problems experienced by the p l a r , t GII combined s c w e l - overfloks and s ludge handl ing a re c u r r e r ~ t l y be ing addressec! in rhe Oiric' r; fac i1 i . t i c . s p la .nn ing e f for t . Toledo has rece ived S t e p One g r m t s for i n s t a l l a t i o n o f a r egu la to r t e l eme te r i -ng syst.em.

T h e Akron treatment p l a n t i s operat..pd by thc: C i t y . I t s e r v e s a n A:-P<? of 75 square miles, i n r l u d i n g some sllrrounding <,omnlunities. Tbc se rv iced population is about 375,000. I t has a des ign : , apac i ty o f 3$!~, MR/d (90 MGD) w i t h n rn,lxin;um hydraul ic capaci- ty of 7 8 7 !4a/d (207 MGD). The p i a n t was o r i g i n a l l y b u i l t i n 1 9 2 1 and has been a lmost comple te ly rebui l t s ince .

The p l a n t h a s t h e a c t i v a t e d sic:dpe process w i t h pre-aerariou and e f f l u e n t c h l o r i n a t i o n . E f f l u e n t i s d ischarged t o the Cllyahoga River . A phospha te ban i n de t e rgen t s was p u t i n t a e f f e c t i n Akron i n e a r l y 1 9 7 3 .

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Primary sludge is chemically conditioned. vacuum filtered and incine-rated. The filtrate is returned to the primary clarifier. The ash from theincinerator is hauled to an ash dump. The waste activated sludge. on theother hand. is graVity thickened and subsequently oxidized in two Z1mpro (wetair oxidation process) units. This oxidation process pumps sludge and airunder high pressure into a reactor with a temperature of 450°F where thesludge is chemically oxidized into ash. water and gas. The heated gas is

,recycled for heating and fuel. 'the ash and water mixture goes to a deca.ntingpond from which. the supernatant is returned to the plant for retreatment.

There is a channel ahead of the plant to bypass raw sewage in the eventof excess flow or plant shutdown. Occasionally, a portion of the primaryeffluent is discharged directly to the River to relieve the load on thesecondary process. There are 24 Imhoff Tanks remaining from the originalplant which are used for storage of excess stormwater flows and indus~rial

spills.

WAYNE COUNTY (WYANOOTTE)

The wyandotte treatment plant is owned and operated by the Wayne CountyBoard of Public Works. It was originally constructed in 1939 and expanded in1964. The present design capacity is 240 Mild (63 MGD) with a wet weatherflow of 290 M1!d (77 MGD). There is a pumping station adjacent to the plantwith capacity to divert excess flow to the Detroit River. The treatmentplant receives various industrial wastes as well as alum sludge from nearbywater t~eatment plants.

The treatment process consists of primary sedimentation with ferricchloride added for phosphorus removal. Chlorine is added before and aftersettling. The plant is essentially covered, making maintenance difficult.

The sludge from the plant is thickened, vacuum filtered and incineratedAsh is disposed of in a lagoon. The constant failure of the plant's twoincinerators presents a rather severe problem affecting the final effluentquality. When one of the incinerators is out of service, a significantportion of the sludge is recycled back to the influent and retained in thesystem. The impact is evident in the high effluent BODs, suspended solidsand phosphorus concentrations. The plant personnel have attributed theincinerator breakdown to the formation of "clinkers" in the furnace as aresult of ferric chloride addition for phosphorus removal.

The Wyandotte Pumping Station #5, adjacent to the treatment plant, pumpscombined sewage to the river whenever the ~imum hydraulic capacity of theplant is exceeded. The quantity of this bypass is estimated from the pumpingtime and power setting. Over the past five years, the annual volume ofbypass sewage ranged from 2810 M1 (740 MG) in 1970 to 12540 M1 (3300 MG) in1973.

Construction of a new 380 Mild (100 MGD) pure oxygen activated sludgeplant is currently underway and will be completed in late 1975. operation isexpected to commence in early 1976.

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E R I E

The Ci ty o f Erie h a s a wastewater t rea tment p lan t which has recent ly been expanded from a capac i ty o f 170 MR/d ( 4 5 MGD) t o a des ign capac i ty of 247 MR/d (65 MGD). A l l t h e u n i t p r o c e s s e s commenced o p e r a t i o n i n J a n u a r y 1975. The p l a n t r e c e i v e s a b o u t YO m / d ( 8 MGD) o f s t r o n g i n d u s t r i a l waste f rom the Hammermill Paper Company. The pu lp was t e has caused pe r iod ic p l an t u p s e t s d u e t o i t s h igh so l id s and o rgan ic l oad ings .

The treatment provided is a c t i v a t e d s l u d g e w i t h f e r r i c c h l o r i d e a n d polymer addi t ion for phosphorus removal which began in Apr i l 1975.

The e f f l u e n t i s ch lo r ina t ed and d i scha rged t o Lake Erie. The raw primary s ludge is mixed w i t h waste ac t iva t ed s ludge , t h i ckened , vacuum f i l t e r e d a n d i n c i n e r a t e d . The a s h is disposed of on land.

The City has 59 combined sewer overflow poi:l ts with 1 3 of t hese d i s - c h a r g i n g d i r e c t l y t o P r e s q u e Is le Ray i n Lake Erie. The remain ing po in ts go i n t o t y i b u t a r y streams before reaching Presque Isle Bay. A c o n s u l t a n t ' s s t u d y i n 1972 estimated the phosphorus loading from combined sewer overf lows t o be in the ne ighborhood of 10 kg/day. The Ci.ty i s p resen t ly cons ide r ing the s tudy ' s r ecommenda t ion t ha t t he ove r f low be s to red i n r e s e r v o i r s and pumped t o t h e t r e a t m e n t p l a n t l a te r a t a low rate .

CLEVELAND WESTERLY

The Wester ly P lan t ' s 1974 average f low was 148 MR/d (39 MGD). I t is t h e o l d e s t o f t h e t h r e e C l e v e l a n d t r e a t m e n t p l a n t s . The p l a n t i s l o c a t e d i n a h i g h l y i n d u s t r i a l i z e d downtown a r e a a n d r e c e i v e s v e r y s t r o n g i n d u s t r i a l was tes .

The p l an t p rov ides p r imary t r ea tmen t w i th i t s Imhoff Tanks . I ron sa l t s were added for phosphorus removal from November 1972 to Ju ly 1974 . On.ly polymer has been added since August 1974. Despite the chemical additim, e f f luent phosphorus concent ra t ions have remained in the range of 2 t o 3 mg/R. The 1974 ave rage concen t r a t ions fo r BOD5 and suspended sol ids were i n e x c e s s o f 100 mg/R.

The sludge i s d i g e s t e d , vacuum f i l t e r e d a n d i n c i n e r a t e d . T h e r e are two i n c i n e r a t o r s i n t h e p l a n t b u t o f t e n o n l y one i s i n o p e r a t i o n . -It t h e time of t h e v i s i t , t h e r e were mountains of f i l t e r e d s l u d g e ;md a s h i n t h e v i c i n i t y o f t h e s l u d g e b u i l d i n g w h i c h i s a d j a c e n t t o t h e s h o r e .

There are f a c i l i t i e s f o r b y p a s s i n g s e w a g e w i t h o n l y t h e time of bypass r eco rded . In 1974 , t he ave rage du ra t ion o f bypass ave raged 36 hours a month.

Cons t ruc t ion is underway f o r a xew 190 ML/d (50 MGD) physical-chemical t rea tment p lan t which w i l l p rovide chemica l coagula t ion and carbon adsorp- t ion . Comple t ion da te i s s c h e d u l e d f o r l a t e 1979.

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FORT WAYNE - The C i t y bL' F o r t Wayne owns and ope ra t e s t he t r ea tmen t p l an t . The

e x i s t i n g p l a n t was cons t ruc t ed i n 1940 t o p rov ide s econda ry t r ea tmen t fo r a design f low of 91 MR/d (24 MGD). It has s ince been expanded to p rovide secondary t reatment to 123 W/d (32 MGD) and primary .to 228 MR/d (60 MGD). Ch lo r ina t ion capac i ty i s 228 MR/d (60 MGD).

The ch lor ina ted e f f luent f rom the secondary t rea tment sys tem is d i s - charged to a 40-acre polishing pond. The pond e f f l u e n t g o e s i n t o t h e Maumee River. Phosphorus removal was i n i t i a t e d i n J u l y 1 9 7 3 w i t h t h e a d d i t i o n of l iquid a lum. Throughout 1974, e i ther ferr ic chlor ide or a lum was added t o t h e p r i m a r y e f f l u e n t .

Raw s ludge f rom the p r imary se t t l ing t anks is anaerobica l ly d iees ted and pumped t o a sludge lagoon. The methane gas is r e c y c l e d f o r h e a t i n g and f u e l . The waste a c t i v a t e d s l u d g e is r e t u r n e d t o t h e w e t well and mixed w i t h t h e incoming raw sewage.

The sewage system serviced by t h e p l a n t h a s a t o t a l of 50 combined sewer ove r f low loca t ions . Under i t s Na t iona l Po l lu t an t D i scha rge E l imina t ion System (NPDES) munic ipa l permi t , the Ci ty i s r equ i r ed t o submi t p l ans fo r ob ta in ing add i t iona l i n fo rma t ion on t he quan t i ty , qua l i t y and impac t o f t hese d i s c h a r g e s by J u l y 1, 1975. Prel iminary designs of necessary t reatment f a c i l i t i e s are r equ i r ed by J u l y 1, 1976. The t r ea tmen t p l an t p re sen t ly has an EPA funded p i lo t p l an t demons t r a t ion p ro j ec t on the t rea tment o f combined sewer overf low. The process involves screening, use of hydrasieves, centr i - fuga l s c reens and a ro ta t ing microscreen . The e f f l u e n t is d i s c h a r g e d t o t h e 40-acre polishing pond.

The p l a n t i s cur ren t ly be ing expanded to p rovide fu l l secondary treat- ment t o a l l 228 MR/d (60 MGD).

WEST WINDSOR

The West Windsor P l a n t is owned and operated by the Ci ty 's Department of P u b l i c Works. It i s t h e l a r g e r of t h e two t r e a t m e n t p l a n t s i n t h e c i t y . The p l a n t is d e s i g n e d t o o p e r a t e e f f i c i e n t l y a t 100 MR/d (22 MIGD). O r i g i n a l c o n s t r u c t i o n s t a r t e d i n 1967 and t h e p l a n t was p l a c e d i n o p e r a t i o n i n A p r i l 1970. The average month ly f low reached des ign capac i ty ear ly i n 1972. I n d u s t r i a l wastes c o n s t i t u t e a b o u t o n e - t h i r d of i ts hydraul ic f low.

The p lan t p rovides p r imary t rea tment and ch lor ina t ion to i t s dryweather flow. It has four p r imary se t t l ing t anks . Phosphorus removal fac i l i t i es were ins t a l l ed i n Feb rua ry 1974 w i th i n t e rmi t t en t (40% of t h e time) a d d i t i o n o f f e r r i c c h l o r i d e d u r i n g t h a t y e a r . From August 1974 to February 1975, the p l a n t w a s t h e s i t e o f 3 Canada/Qntario Research Study on t h e s e t t l e a b i l i t y o f chemica l f locs a t high overflow rates. Normal p l a n t o p e r a t i o n was d i s r u p t e d . Since February 1 9 t 5 , t he p l an t has been con t inuous ly app ly ing alum f o r phosphorus removal.

10

The s ludge from t h e p r imary s e t t l i n g t a n k s i s e i t h e r vacuum f i l t e r e d o r cen t r i fuged p r io r t o l and d i sposa l . The re a r e no s l u d g e i n c i n e r a t i o n f a c i l i t i e s .

The C i t y of Windsor has about 25 combined sewer over f low poin ts a long t h e r i v e r f r o n t i n t e r c e p t o r w h i c h l e a d s t o t h e West Windsor p l a n t . The over- f low weirs a t these po in t s have been ad jus t ed by t h e C i t y t o d i v e r t a maximum flow of 2.5 times d rywea the r f l ow to t he p l an t du r ing r a ins to ru l s . The excess i s d i s c h a r g e d d i r e c t l y t o t h e D e t r o i t R i v e r . P r e s e n t l y , t h e p l a n t w i l l t r e a t f l o w s up t o 205 Ma/d (45 MIGD). Flows i n e x c e s s of t h i s s t i l l r ece ive chemica l add i t ion bu t w i l l bypass t he p r imary s e t t l i ng t anks and go d i r e c t l y t o t h e o u t f a l l where ch lor ine is app l i ed . The r i v e r o u t f a l l has s u f f i c i e n t l e n g t h t o b e u s e d as a ch lor ine contac t chamber .

Cons idera t ion i s be ing g iven to expanding the p lan t capac i ty by an a d d i t i o n a l 68 t o 9 1 W / d (15 t o 20 MIGD). Pr imary t reatment with chemical a d d i t i o n w i l l be provided.

LONDON (GREENWAY) I

The City of London h a s f i v e p l a n t s t r e a t i n g a t o t a l f l o w i n e x c e s s of 130 MR/d (29 MIGD). The Greenway p l a n t is the l a rges t w i th an ave rage f l ow of about 82 MR/d (18 MIGD). A s i g n i f i c a n t i n d u s t r i a l waste load t o t h e p l a n t i s provided by a brewery.

The t rea tment p rovided i s a c t i v a t e d s l . u d g e w i t h t h e c h l o r i n a t e d e f f l u e n t be ing d i scha rged t o t he Thames River . The p l an t has been ach iev ing e f f luen t phosphorus concentrat ions of less than 1 mg P/R wi thou t d i r ec t chemica l addi t ion s ince October 1973.

The sludge produced i s thickened by a i r f l o t a t i o n , vacuum f i l t e r e d and i n c i n e r a t e d . F e r r i c c h l o r i d e a n d lime are used fo r s ludge cond i t ion ing . The f i l t r a t e from the vacuum filters is r e t u r n e d t o t h e p l a n t . Ash i s d lsposed of i n two lagoons.

I n t h e e v e n t of high f low, a p o r t i o n of t h e waste receives only pr imary t rea tment and i s d ive r t ed t o t he ch lo r ina t ion chamber .

P l ans are unde r cons ide ra t ion fo r expand ing t he p l an t t o 164 MJ2/d (36 MIGD) sometime before 1977.

KITCHENER

The Kitchener Water Pol.!.ution Con t ro l P l an t is ope ra t ed by t he Min i s t ry of the Environment for the Regional Municipal i ty of Waterloo. The o r i g i n a l p l an t da t e s back t o t he 1920’ s and was expanded i n 1963. The primary design capac i ty i s 52 MR/d (11.5 MIGD) w i r h a secondary capacity of 61 MR/d ( 1 3 . 5 MIGD) .

The t r ea tmen t p rocess i s conven t iona l ac t iva t ed s ludge w i th t he chi-ori- n a t e d e f f l u e n t b e i n g d i s c h a r g e d t o t h e Grand Ri.ver. Aluminum su lpha te has

11

been added f o r phc?sphorus removal s ince January 1974. A t t h e p r e s e n t time €1111 scale tex:! irlg w i t h i r o n salts is in p rog res s .

A combination of anae rob ic d iges t ion , vacuum f i l t r a t i o n , s l u d g e l a g o o n i n g and l and app l i ca t ion i s used i n t h e d i s p o s a l of s ludge f rom th i s p l an t .

Excess f l o w t o the p l an t bypasses p r imary t r ea tmen t and goes d i r ec t ly t o t he ae ra t ion t anks . The re are no q u a n t i t a t i v e d a t a o n t h e volume of bypass. Estimates are made on t he number of hours bypassed.

Cons t ruc t ion of f a c i l i t i e s e x p a n d i n g t h e p l a n t c a p a c i t y t o 1 0 0 MRId (22 MIGD) s t a r t e d i n A p r i l 1975.

12

DATA COLLECTION AND ANALYSIS

Treatment plant records f rom January 1970 to December 19'74 were reviewed and monthly summary da ta on the fo l lowing parameters ob ta ined by the Regional Off i ce s t a f f :

- plant f low (average , maximum, minimum) - i n f l u e n t a n d e f f l u e n t c o n c e n t r a t i o n s on phosphorus, BOD5 and

- bypass - p r e c i p i t a t i o n

suspended so l id s

Information on the phosphorus removal program a t each p l an t was ga thered . Major cons t ruc t ion and research ac t iv i t i e s which might have affected normal p l a n t o p e r a t i o n were a l s o n o t e d .

LOADING DATA

The main purpose of analyzing the loading data i s t o compare t h e l o a d i n g f i g u r e s as r e p o r t e d by t h e j u r i s d i c t i o n s in 1974 w i th t hose ca l cu la t ed by t h e Regional Off ice on a uni form bas i s .

The f o r m u l a u s e d b y t h e R e g i o n a l O f f i c e i n t h i s s t u d y f o r c a l c u l a t i n g the annua l l oad r a t e is as fol lows.

Annual Loading Rate = - ) sum over

12 months

Average

f low rate

Average monthly c o n c e n t r a t i o n

(mg/R) -

The c a l c u l a t e d l o a d i n g s a re compared w i t h t h e r e p o r t e d f i g u r e s i n Table 2 . With few except ions, the two sets o f f i g u r e s a re g e n e r a l l y i n agreement. In most cases, t h e f i g u r e s are w i t h i n t e n p e r c e n t of one anotller. It i s e v i d e n t t h a t m o s t o f t h e l o a d i n g f i g u r e s as r e p o r t e d by the ju r i sd i t . . - t i o n s were c a l c u l a t e d on t h e b a s i s of p l a n t r e c o r d s . O n t a r i o c a l c u l a t e d its r e p o r t e d l o a d i n g s t o IJC on the bas i s o f month ly samples submi t ted to the M i n i s t r y of the Environment.

1 3

TABLE 2

PLANT

DETROIT

CLEVELAND EASTERLY

CLEVELAND SOUTHERLY

TOLEDO

AKRON

WYANDOTTE

E R I E

CLEVELAND WESTERLY

FORT WAYNE

WINDSOR **

LONDON

KITCHENER

TOTAL

COMPARISON OF 19L4 REPORTED AND CALCULATED LOADING DATA

Total Phosphorus

R ~ p r t e d Calcu la ted .. -

13,000 12,700 (1,490)

818 89 7 ( 200)

350 38 9 ( 98)

842 743 ( 300)

572 594 ( 160)

1,650 1 , 7 70 ( 260)

377 * 368 * ( 68)

444 403 ( 53)

113 110 ( 54)

100 1 1 7 ( 46)

42 40 ( 19)

70 74 ( 18)

18,378 18,205

Rep0 r t ed

249,000

7,250

6,290

10,700

8,420

22 , 600

2,220

15,900

1,140

3,720

910

1,400

329,550

BOD 5 Suspended Solids

Reported

519 , 000

9 , 320

4,550

23,600

7,410

28 , 700

6,670

16 , 400

1,920

3,820

1,190

2,480

625,060

Calcula ted

598,000 (318,000)

9 , 260 ( 3,260)

5 , 240 ( 3,720)

19,800 (10,800)

9,510 ( 2,890)

28 , 800 ( 7,140)

6,830 ( 3,820)

15,700 ( 3,810)

1,880 ( 743)

3,690 ( 506)

1,100 ( 456)

1,790 ( 811)

701 , 600

A l l l o a d i n g d a t a i n kfl-ograms p e r day.

S tandard devia t ion shown i n pa ren thes i s .

* - Fi l te red sample .

** - Based on da ta Ernm August t o November only.

1 4

I n g e n e r a l , t h e small d i f fe rences be tween ca lcu la ted and repor ted load ings can be a t t r i bu ted t o round-o f f e r ro r s , conve r s ion t o me t r i c un i t s and the use of a n n u a l a v e r a g e s f o r t h e c a l c u l a t i o n .

It i s no ted he re t ha t t he l oad ing da t a , bo th ca l cu la t ed and r epor t ed , f o r Windsor are p robab ly no t r ep resen ta t ive of t h e a c t u a l p l a n t o p e r a t i o n . I n t h e f i r s t f i v e months of 1974, only one phosphorus sample was analyzed each month because of t h e l a c k of p l a n t l a b o r a t o r y f a c i l i t i e s . I t was not u n t i l t h e l a t t e r p a r t of t h e year t h a t d a i l y samples were t a k e n . F o r t h i s r e a s o n , t h e c a l c u l a t e d l o a d i n g i n t h i s s t u d y was based on monthly averages from August t o November only. Furthermore, there was a f u l l s c a l e r e s e a r c h p r o j e c t on s i t e from August 1974 t o February 1975 which s ign i f icant ly in te r - f e red w i th t he no rma l p l an t ope ra t ion .

With the excep t ion o f K i t chene r , a l l t h e t r e a t m e n t p l a n t s v i s i t e d h a v e monthly data summaries . Ki tchener 's records are kep t on a weekly basis. For the purpose o f th i s s tudy , the weekly summaries were converted to monthly summaries.

BYPASS DATA

One o f t h e o b j e c t i v e s o f t h i s s t u d y was t o assess t h e p o l l u t i o n l o a d i n g s from plant bypasses and combined sewer overflows.

Dur ing t he p l an t v i s i t s , one o f t he mos t s t r i k ing obse rva t ions made was t h a t t h e r e are no q u a n t i t a t i v e d a t a on bypasses and overflows. The study a l s o r e v e a l e d t h a t a l l t h e j u r i s d i c t i o n s v i s i t e d are cogn izan t o f t h i s def ic iency and most have correct ive measures e i ther a l ready underway or under cons ide ra t ion . Tab le 3 ou t l ines i n fo rma t ion on ex i s t ing da t a and fu tu re remedial programs. It is i m p e r a t i v e t h a t c o n t i n u o u s e f f o r t s b e made i n t h i s area.

ANALYTICAL METHODS

In each s ta te , t h e a n a l y t i c a l t e c h n i q u e s u s e d i n m e a s u r i n g p o l l u t a n t s i n a t r e a t m e n t p l a n t are s u b j e c t t o i n d e p e n d e n t v e r i f i c a t i o n by the agency which i s s u e s t h e NPDES permi ts . Compl iance moni tor ing which involves the ana lys i s of s p l i t samples is requi red under the permi t sys tem. Any dev ia t ions f rom accep tab le l abo ra to ry p rocedures are c o r r e c t e d .

I n O n t a r i o , similar independent monitor ing of eff luent samples is c a r r i e d o u t by M i n i s t r y of t he Env i ronmen t s t a f f du r ing p l an t i n spec t ions .

15

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A COMPARATIVE STUDYPLANT PERFORMANCE

The overall performance of each of the twelve treatment plants in 1973and 1974 i. summarized in Table 4 where the averale effluent concentration.for phosphoru.. BODs and 8u8pended solid. are listed. In the Appendix. themonthly concentrations from January 1970 onwards are graphically di8playedfor each plant.

In 1974. only Fort Wayne and London achieved average effluent pho.phoru.concentration. of lee. than 1 ma pIt. Effluents from Cleveland Southerly.Kitch.ener and Windsor were slightly higher. The re.t of the plant. hadconcentrations ranaing from 1.8 to 6.7 ma pIt. In 1973. none of the twelveplants produced effluent with pho.phorus concentration. le.. than 1 ma.P/1.

Detroit, Wyandotte and Toledo have been experiencinl problema with their.ludie handling facilitie.. At Detroit, add1tionalincinerator faci11tie.have racently been completed and are in the stale of start-up and debugiing.Plant expanlion il underway throulh a pha.ed conetruction program. AtWyandotte, the primary plant will be expanded to provide pure oxygen acti-vated Iludae treatment for its waite.. Con.truction il clo.. to completionand .Yltam .tart-up will commence in the aarly month, of 1976.

Cleveland Weat.rly ia the site of a n8W phyaical-chem1cal treatmentplant due for completion in 1979. At preaent. the plant ia in urgent need ofproper operation and maintenance. Thick layers of ecum can be obaerv8dcovering moat of the Imhoff tanka. Solida carryover 1a evident and isreflected in the effluent luapended aolida concentrations of over 100 malt.The new plant will provide lime addition. recarbonat1on and carbon adaorption

to the waatea.

The relatively hiBh BODs and auepended ,olid, beina dilcharaed from theWelt Windlor plant can be attributed in part to a fullicale relearch projectwhich 8ianificantly affected the operation of the plant.

The Erie treatment plant il experiencina periodic upleta durinaitlItart-up period due to the extr.mely h1ah lolid. and oraanic loadinal fromit. major induatrial dilcharaer. Hammermill Paper Company. The actualeffluent total pholphoru8 concentration 18 8omewhat hiaher than indicatedlince the analYlil wa. performed on 4 filtered aample. Aa of October 1975

unfiltared lample. are bo1na analyzed.

17

TABLE 4

AVERAGE EFFLUENT CONCENTRATIONS (me/!?,)

Tota l Phosphorus as P

PLANT 197 3 1974

DETROIT 6 . 0 3.9

CLEVELAND 1.7 2.1 EASTERLY

CLEVELAND 1.7 1.1 SOUTHERLY

TOLEDO 2.4 2.2

AKRON 2.2 1 . 8

WYANDOTTE 6.5 6.7

ERIE 2.5* 2.3*

CLEVELAND 2.7 2.7 WESTERLY

FORT WAYNE 2 . 1 0 .9

WINDSOR 3.8 1 . 3

LONDON 1.4 0.5

KITCHENER NO DATA 1.1

BOD 5

197 3 1974

77 75

6 17

19 18

30 30

18 23

81 89

14 16

102 101

15 8

76 45

9 10

18 26

Suspended Solids

1973 1974

173 179

7 21

25 14

64 63

30 28

118 110

49 41

93 106

15 16

70 44

13 13

15 28

* - Filtered sample; as of October 1975, unfiltered total phosphorus is being analyzed according to the approved EPA method.

18

There are four exemplary p lan ts which have been cons is ten t in d i scharg ing e f f l u e n t o f r e l a t i v e l y h i g h q u a l i t y . T h e s e p l a n t s are i d e n t i f i e d a s C l e v e l a n d Sou the r ly , Fo r t Wayne, London and Kitchener .

COMPARISON OF ACTUAL AND TARGETED LOADINGS

I n i t s 1974 Annual Report , the Board reported that phosphorus removal f a c i l i t i e s were provided for 94 percent o f the munic ipa l wastewater i n t h e Lake Erie Basin. The Board f u r t h e r s t a t e d t h a t t h e o p e r a t i n g e f f i c i e n c y of t h e s e f a c i l i t i e s v a r i e d f r o m p l a n t t o p l a n t . The f i n d i n g s of t h i s s t u d y s t r o n g l y s u p p o r t a n d c o r r o b o r a t e t h e B o a r d ' s a s s e r t i o n o n t h e o p e r a t i n g e f f i c i e n c y o f s u c h f a c i l i t i e s .

I n F i g u r e 2 , t h e 1974 ac tua l phosphorus loading f rom the twelve treat- ment p l a n t s a n d t h e t a r g e t e d l o a d i n g o b t a i n a b l e when a l l t h e s e p l a n t s h a v e achieved the 1 mg/R phosphorus l eve l a re compared, I t i s n o t e d t h a t when t h e t a r g e t e d l e v e l i s achieved , the to ta l phosphorus loading f rom the twelve p l a n t s w i l l be reduced from 18,000 t o 5 ,700 kg /day . This represents a decrease of a lmost 70 pe rcen t .

It i s i n t e r e s t i n g t o n o t e t h a t t h e d i f f e r e n c e b e t w e e n t h e a c t u a l and t a rge ted l oad ings fo r t hese twe lve t r ea tmen t p l an t s accoun t s f o r about 28 p e r c e n t of t he r epor t ed Lake Erie phosphorus loading f rom municipal , indus- t r ia l a n d t r i b u t a r y s o u r c e s as r e p o r t e d by t h e j u r i s d i c t i o n s i n t h e 1974 Water Q u a l i t y Board Annual Report.

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CONCLUSIONS AND RECOMMENDATIONS

1. The 1974 phosphorus loading f o r t he ma jo r mun ic ipa l d i scha rges i n t he Lake Erie Basin, as r e p o r t e d by t h e j u r i s d i c t i o n s t o t h e Water Qua l i ty Board r e p r e s e n t t h e b e s t estimate a v a i l a b l e .

The load ings are based on comple te p lan t records cons is t ing genera l ly o f f i v e 24-hour, flow proportioned, composite samples per week. While i t i s obv ious t ha t r e f inemen t s i n s ampl ing and ana ly t i ca l t echn iques w i l l f p r the r improve fu tu re estimates, the Water Quality Board is of t h e o p i n i o n t h a t no ex t r ao rd ina ry e f fo r t s need t o be t aken a t the present : time .

2. Seven of the twelve municipal p lants have not been achieving t h e phos- phorus concen t r a t ion of 1 mg P / % i n t h e i r e f f l u e n t s d e s p i t e t h e f a c t t h a t t h e y h a v e i n s t a l l e d p h o s p h o r u s r e m o v a l f a c i l i t i e s .

A 70 p e r c e n t r e d u c t i o n i n t h e t o t a l m u n i c i p a l p h o s p h o r u s l o a d i n g i n t h e Lake Erie Basin w i l l be achieved when t h e e x i s t i n g f a c i l . i t i e s are ope- r a t e d t n p rovide a c o n c e n t r a t i o n of 1 mg P /R i n t h e e f f l u e n t .

3. Unmoni torcd sewage bypass wi th in the t rea tment p lan ts does no t appear to c o n s t i t u t e a s i g n i f i c a n t port-i.on of the phosphorus loading. In most ca ses , i n -p l an t bypasses are i n c l u d e d i n t h e f i n a l e f f l u e n t . s a m p l e s .

4 . There are i n s u f f l c i c n t q u a n t i t a t i v e d a t a on combined sewer and stormwater overflows. Programs are underway in many j u r i s d i c t i o n s t o assess t h e impact of such overf lows and to implement remedial act ions where necessary.

The p rogres s of these remedial programs w i l l be c lose ly moni tored by t h e Great Lakes Water Qua l i ty Board through i t s commit tee s t ruc ture .

5. T h r o u g h o u t t h e p l a n t v i s i t s , t h e most f requent cause of o p e r a t i o n a l problems exper ienced in some p l a n t s was inadequate sl.udge hand1i.ng f a c i l i t i e s . I n D e t r o i t , W y a n d o t t e , and Toledo the phosphorus removal p r o g r a m h a s r e s u l t e d i n a d d i t i o n a l s l u d g e p r o d u c t i o n f a r i n excess of the p l an t s ' s ludge hand l ing capac i ty . Remed ia l ac t ions are underway i n these p l a n t s .

6 . This eva lua t ion s tudy has p rovided the I J C R e g i o n a l O f f i c e s t a f f w i t h a u n i q u e o p p o r t u n i t y t o v i s i t m a j o r wastewater t r e a t m e n t f a c i l i t i e s and meet many munic ipa l t rea tment p lan t and s t a t e and p rov inc ia l r egu la to ry p e r s o n n e l r e s p o n s i b l e f o r t h e i r o p e r a t i o n .

2 1

Monthly e f f luent to ta l phosphorus , BOD5 and suspended solids concen- t r a t i o n s of each t rea tment p lan t f rom January 1970 t o p re sen t .

i n d i c a t e s t h e time when phosphorus r emova l f ac i l i t i e s commenced opera t ion .

i n d i c a t e s t h e time when phosphorus l imi t a t ions were placed on domest ic de te rgents .

2 3

. . . . . .

24

... .... ..... ..... . . . . . I . ....... ........ ...................... . . . . . . . . . . . .

1970 1971 1972 1975

ILIVELARO i A l i t R L Y bo" tiFL"EH,

I* * G I 1 18D

150

12w

90-

W

. . ........ . . I . " I ............. . . " I . . I . I". ~ 30' : . . . . . . ................ ........... .............. ............... .: . .

................................... ........................................ ................ ......................

.......................................................... ................................................................ 1970 1971 1972 1973 1974 1975

YEAR

, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............... . . . ............... ....... .......................... ......... ............................ ............... ................................. .................. . . , I

.................................. .......................................................... .............................................................. 1910 I l ' i I972 2977 lY74 1975

25

. . . .

. .

26

. . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . ... . . . ... ....... . . . .. -. . . . . . ........ . . . . . .. I.

....... ........ . . . . . . . . . . . . . . . . . . .... ........ . . . . . . . . . .... . . . . . ... . . . . . . . . . . . . . . . . . . . . . .... ........................ ................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....................................... ............................................ ................................................ ................................................. ................................................. ................................................. ................................................. 1 0 7 1 "311 1 " V 7.T 1979 1175 .r"

60

. . . . . . . . . . . . . I . . . . . . . . . . . . . . . 30

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I 1970 1971 1972 1973 1974

I YEAR

710

225

180

157

90-

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . I . . .. I . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . ...... . . . . . . . . . . . . ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1971 1972

27

pharpha le ban

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1970 1971 1?72 3 7 3 1974 1975

YEAR

AKRON Boo EFFLUENT

180 I N n d L

150

120

9D

W

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1970 1971 1972 1973 1974 1975 YEAR

Z7R

229

law

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I.

..................... ".. 1970 1971 1'172 1973 1974 1975

YEAR

28

1 YFAR

WANWTTE Boo EFFLUENT

I N neit 18V

150

. . . . I . . . . . . . . .I .I . . . . . . . I . I . . . . . . . . . . . I . ." " I .I ............. ............... . . . . 120 i " ." ." .. I"

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1970 1971 1972 1973 1974 1975

YEAR

. I

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29

YEAR

IRri. I'FNIISYLL.INtA

180 !,hi> I F i l U i l l l li rr/1

150

12a

gG-

60'

30' . . I ... .".. I . .

. I . .

. . . . . . . . . I" .. .......................... ........................................... ......................................................... ............................................................... .................................................................. 1970 1971 1g72 1973 1974 1475

YEAR

I

... 1.1 ... I.. I..

I -.,. . . . ..I. . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................ ................................. .......................................

. Y 7 , !9:: '973 19/11 l l i i Yinll

30

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. ,.. . . . . . . .

31

YEAR

FORI WAYNE

180 BOD EFFLUENT

I N M d i

150

120

91).

KO'

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1970 i97i 1972 1971 1'174 1975 YEAR

.._ ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..................................... I . . . . . I .1* '" ."" . . . 1 " 1 . . " .,.. ll.ll..*".I".,........ .... ".. ............................... I W J 1971 :Y/i i l l3 ?P74 197'1

m a

32

1 YEAR

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. . . . . . . . . I 1 1. ........ . .I I.. ........ ........ ........ ........ ........

.... ........ ............ ............. ...... .............. ...... .................... ................. ..................

1970 1971 1'12 1973 1974 l?75 .

YtAR

BOD EWLUTNT LOiiWN

IN "dl

1970 1971 1972 1973 1974 1975

I YEAR

. I

. I I . .

iii' 1 i . . . . . . . . . . . . ................. ..................... .............................. .............................. *... ............... ................................................................. ................................................................. . . 1470 1971 1972 1973 1974 1975

YEAR

34