Flint River- final report- environmental engineering

8/19/2019 Flint River- final report- environmental engineering

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Figure 8 Simulation model used for zinc in Model Maker 4 ........................................................ 23 Figure 9 Model Maker 4 simulation ............................................................................................. 24

Figure 10 Total concentration of heavy metal in the water column ............................................. 25 Figure 12 Total concentration of Cadmium in the water column ................................................. 26

Figure 13 Weight fraction of heavy metals in the sediment column ............................................ 26

Figure 14 Cadmium weight fraction in the sediment column....................................................... 27 Figure 15 Suspended solid concentration in the water column .................................................... 27 Figure 16 Weight of zinc and Copper in the sediment column ................................................... 28


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1 Introduction

1.1 Location and features of Flint river

Flint River is located in the state of Michigan in United states of America, with 126.0km long,

Flint River is the main water resource for the city Flint and it flow through the countries if

Lapeer, Genesee, and Saginaw. There are three dams along the Flint River. The first one is

located in Richfield Township following is Utah Dam then the last one is Hamilton Dam. The

Richfield Township Dam form the Holloway Reservoir which is a water supply for Flint.1

In the city of Flint, the river flows past the sites of several former General Motors factories, most

notably Chevrolet's first assembly plant, which was bisected by the river, and downtown through

the campus of the University of Michigan–Flint and Riverbank Park.

Figure 1 Flint river in Michigan

1.2 Study segment for Flint River

In our case, in order to study the pollutant in the water body. We choose the segment below city

flint because the downstream after Flint it has two Waste water treatment plant, which is the

major pollutant for Flint River. Finally, we choose from Mill Road to Silver Creek as our study

segment and the whole length is 60.2km.


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August

Source Discharge(m3/s)

Discharge Concentration

Suspended Solids

(mg/l) (kg/d)

Total Zinc

(ug/L)

Total

Cadium

(ug/L)

Total

Copper

(ug/L) Upstream

Boundary 2.66 13.5 7.7 0.067 2.9

Flint WWTP 1.68 4.1 55 0.16 8.3

Flint Fly Ash 0.04 39.5 63 1.32 80

Brent Run 0.15 5.9 3.8 0.11 3.8

Ragnone WWTP 0.69 58.7 84 0.54 28.5

Pine Run 0.06 7 5 0.04 3.8

Silver Creek 0.085 5.8 5 0.04 3.8

December



Suspended Solids

(mg/l) (kg/d)

Total Zinc

(ug/L)

Total

Cadium

(ug/L)

Total

Copper

(ug/L)

Upstream

Boundary 26.35 7.4 4 0.05 2

Flint WWTP 2.19 7.8 54.3 0.18 16

Flint Fly Ash 0.1 23.5 220 2.89 127

Brent Run 0.57 7.7 7.67 0.097 2.93

Ragnone WWTP 1.14 40.7 75 0.21 18.5

Pine Run 0.67 5.5 3.33 0.013 2.1

Silver Creek 0.62 3.5 3.67 0.01 1.8

March



Suspended Solids

(mg/l) (kg/d)

Total Zinc

(ug/L)

Total

Cadium

(ug/L)

Total

Copper

(ug/L)

Upstream

Boundary 93.4 15.5 7.24 0.025 2.48

Flint WWTP 2.66 5.35 71 0.11 18.2

Flint Fly Ash 0.18 5.84 120 0.93 71.4

Brent Run 1.51 13.4 10.6 0.032 5.14

Ragnone WWTP 1.12 50.9 59.7 0.257 27.8

Pine Run 2 14 7 0.03 2 Silver Creek 2 14 7 0.03 2

Table 1 Data of the effluent from different station [2]

1.3 Preparation for building model

1.3.1 Model of discharge


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During the August the flow rate form upper stream is 2.66m3/s and except the Flint WWTP

others flow rate are much lower. In our case, to make our model simpler. We decided to combine

Brent Run, Pine Run and Silver Creek together to the Ragnone WWTP as one-point source

discharge because they have similar environmental condition like the lower pollutant and flow

rate.

So we divided it into 3 parts. Settingthe Flint WWTP as our point source discharge1 and

Ragnone WWTP as our point source discharge2. In our model, it’s 1.2km from the Mill Road to

discharge1. The distance between discharge1 and discharge2 is 29km then 29.80km below

discharge2 is Silver Creek.

Figure 3 Overview of study segment

*+,+-

./010234 5363 78/ 98026 :8;/


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Because the segment we study in Flint River only 60.2km long and Flint River also located in

plain country, so we assume that the elevation doesn’t change a lot form the Mill Road to Silver

Creek.

Parameter Upstream Flint

WWTP

Raganone

WWTP

Length(km) 1.2 29 29.8

X_distance (km) 0-1.2 30.2 60

Cross section area

（m2）

19 19 19

Slope(°) 0.02 0.02 0.02

Average elevation(m) 230 230 230

U_Velocity (m/s) 0.14 0.22 0.28

W_Width (m) 36 36 36

H1_Deepth(m) 0.52 0.52 0.52

T_Temperature(℃) 20 20 20

pH 7.3 7.3 7.3

Table 3 Hydraulic parameters on Flint river

1.5 Contaminant in the Flint River

For our projects we chose biochemical oxygen demand (BOD) as our non conservative pollutant

and three major heavy metals as our conservative pollutants

*+?+*

@08=A0


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measure organic in water. Higher BOD concentration means high concentration of

microorganism which will lead to low DO concentration and others life like fish and plants

cannot survive.

In terms of BOD, it contains carbonate BOD and nitrogen BOD, but in our case we just consider

the carbonate BOD although nitrogen BOD is also an important factor in consumption in water

body.

*+?+- G;:9=25=5 :8405

Suspended solid in the river due to the erosion and others types of particulate form materials

discharge to water body. Although it is not toxicant it will affect the turbidity odor color in the

river. In addition, due to the fact that some of the metals are not fully dissolved in the water,

some of them are subject to sedimentation and settling which is highly affected by the suspended

solid. As a result, it’s very important to study the suspended solid concentration when we

building the model.

*+?+, H=3IC J=634:

!"##$%

Metallic Copper is insoluble in water, but many copper salts are soluble as cupric or cuprous

ions. Copper ions are not likely to be found in natural surface or ground waters. This is because

they are introducing into natural waters of Ph7 or above, these ions quickly precipitate and are

thereby removed by adsorption and/or sedimentation6,5

Copper is not considered to be a cumulative systematic poison , like lead or mercury. In

humans, most of the copper ingested is excreted by the body and little is retained. In lower

organisms and marine animals such as sponges there are some record of accumulation. In

concentrations high enough to be dangerous to humans, copper renders a disagreeable taste to the

water. Threshold concentrations for taste has been reported in the range of 1.0-2.0- mg/L while

5.0-7.0mg/L makes the water completely undrinkable.7,5

Coppe acts synergistically with the sulfates of other metals such as Zinc and Cadmium to

produce potent toxic effects on Fish 8,9. Synergism also exists between copper and mercury but in


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our studies Zinc and Cadmium are only considered. Copper standards for aquatic systems in the

state of Michigan is 1.0 mg/L which is the same as USPHS water standards.5

!'()*+)

The elemental form of Cadmium is insoluble in water although the chloride, nitrate and sulfate of

this metal are highly soluble. Cadmium salts may be found in wastes from electroplating plants,

pigment works, textile printing, lead mines and certain chemical industries. Cadmium is

moderately toxic to all organisms and it is a cumulative poison to mamals. It tends to concentrate

in liver, Kidney, pancreas and thyroids of humans and other mamals.

Cadmium acts synergistically with zinc to increase toxicity. Several studies found that the

cadmium concentration of 0.03 mg/l with combination with 0.15 mg/l of zinc from galvanized

screens caused mortality of salmon fry. The standards for aquatic systems for state of Michigan

is 0.01 mg/l.

,*-.

Some Zinc salts (eg. Zinc chloride and zinc sulfate) are highly soluble in water. These salts are

often found in industrial wastewater from galvanizing industries, and manufacturers of paint

pigments, cosmetics pharmaceuticals, dyes, insecticides and other products. High concentrations

of zinc in domestic water are undesirable from aesthetic standpoint as well as from a health

hazard standpoint. At high concentrations, zinc gives water a milky appearance. Concentrations

as low as 5 mg/l cause a greasy film on boiling of the water.

Zinc has no known adverse physiological effects at normal concentrations. It is an essential and

beneficial element in human nutrition. Zinc exhibits its greatest toxicity toward fish and aquatic

organisms. In soft water concentrations of zinc ranging from 0.1 to 1.0 mg/L reported to be

lethal5


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2 Biochemical oxygen demand and dissolved oxygen in Flint river

2.1 Determining parameters

As we can see in our case, the major pollutant is the sanitary waste from the city which contains

lots of organic materials. Organic materials are highly oxidizing to the dissolved oxygen in the

river. As the table shows below, the data for CBODU is obtained at each point source2. As to the

DO K1 K d Ka Kr we calculate them base on our velocity and depth in the Flint river. For

saturated DO concentration we were using to get three-point data3.

The formulas below we are using for the parameter calculation.

First for before we calculate the concentration of BOD, we have to know Kd, following formulas

we are using for our Kd calculation.

434.0

83.0

!

""#

$%%&

'=

H K

d

Because in our assumption we mentioned before, we assume the area of cross section is the same,

so the Kd in each part (upstream river1 river2) is the same which is equal to 4.8e-06/d

But then we have to consider the temperature effect on the biodegrade rate so we using the

formulas below to correct it. But due to the average temperature in this case is 20 degrees, so it’s

the same as we calculate.

( ) ( ) 20

20d )04.1( !

=

T

d T K K

In this case, Cs1 is search from the book[3] Principles of Surface Water Quality Modeling and

Control, So using the Cs at our this level, we finally calculate the Cs is 10.46mg/l. Because in

our case we have less change on elevation, therefore we assume that the Cs is the same in whole

segment.

Cs=Cs1*(100-0.0035H)/100

As to the reaeration rate base the equation below we calculate it. Although the cross-section aera

is the same in this case, flow rate is different. In addition, because the average depth of river is

less than 8feet, so we decided using this formulas:

85.1

67.06.21

H

U K

a = 0!H!8


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Also, we have to consider the temperature effect on the Ka ,but due to the same condition as Kd

mentioned .So Ka is the same as our result which

K a1=1.82e-05 k a2=2.42e-05 kaup=1.42e-05

( ) ( ) 2020a

)04.1( !=T

a T K K

On the initial values of DO concentration. Base the data we collect 2 from each station, then we

case on our decay rate K d and reaeration K a and initial concentration from the point source

discharge L0, then we using the formulas below to find out our initial values in our case.

Dc= ( ) t k t k t k d a

d a a d e D e e

k k

L k !!!

+!

!

0

0

Then after we calculate the deficit in each point we used the Cs in that point minus Dc and we

can get our DO concentration.

Parameter Meaning Upstream Flint

WWTP

Ragnone

WWTP

Q (m /s) Flow rate 2.66 1.68 1.025

C_BODU

(mg/L)

Concentration of BODU 5 16 30

C_DO (mg/L) Concentration of DO 5.4 4 3.5

K1_BOD5 (day-

1)

BOD5 decay rate 0.187 0.187 0.187

Kd (day-

) BOD5 decay rate 0.415 0.415 0.415

f (L0/y5) Ration of CBOD5 and

CBODu

1.4 1.4 1.4

Cs (mg/L) DO saturation 10.46 10.46 10.46

Kr (day- ) Overall loss rate 0.415 0.415 0.415

Ka (day-

) Volumetric reaerationcoefficient

3.272 4.180 4.648

Table 4 Parameters for BOD and DO [3]


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2.2 Simulation of the BOD with Model Maker 4

In this case because we have two-point source discharges in the whole system. Therefore, in the

model maker we setting the segment between discharge 1 and 2 as a compartment which the

quality of water is affect by the Up stream river and the point source discharge1. So in graph

below we can see clearly river1 is affected by both Flint WWTP and the concentration of Up

stream BOD.

Mass balance we are using in BOD concentration:

L K dx

dL U

d!=

Figure 4 BOD simulation in Model maker

Compartment Equation Initial value (mg/l)

Upstream_BODU When t>1.2, dUpstream_BODU/dt=0Default, dUpstream_BODU/d=

-Kd*Upstream_BODU/U_Upstream

7

Flint_WWTP Qd1Cd1


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River1_BODU When t


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Upstream_D

O

When t>1.2, dUpstream_BODDO/dt=0

Default,((Kd*C01*exp(Kr*t/(U_Upstream))+(Ka_Upstream*(C

s_Upstream-Upstream_DO)))/(U_Upstream))

7

Flint_WWTP Qd1C01

River1_DO When t 30.2, dUpstream_BODDO/dt=0

Default,((-Kd*(6.72*Q01+Ce1*Qe1)/(Q01+Qe1)*exp(-Kr*(t-

1.2)/(U_River1))+Ka_River1*(Cs_River1-River1_DO))/(U_River1))

(QupC0up+Qd1C01)/(Qup+Qd1)

=4.85

Ragnone_WWTP

Qd2C02

River2_DO When t


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Figure 6 Concentration of BOD and DO

In the graph we can see before the point source discharge1, it shows a slightly decrease in this

1.2 km long distance. Obviously the concentration of BOD in this segment are decreasing. On

the contrary, the concentration of dissolved oxygen in this part make a upward trend which

means the oxidation materials in this part was reducing.

Then, when it reach to the point source discharge1 , due to point source discharge1 is the Flint

waste waster treatment plant. The municipal waste usually contains high concentration of

organic materials which will consume the oxygen in water. Therefore, the graph for

concentration of BOD shows us a dramatically increase which up to 12.79mg/l. And in this

period we assume that the mix of BOD is instances. At the same time DO concentration drop

down to 5mg/l in this case and it is not enough for some of the fish living in this segment. Then

as biodegradable function in the river (it shows in Ka reaeration rate in this case), because

velocity in this segment is high so the BOD increase very fast which is the reason why in this

section it didn’t show us sag curve.

Later on, when it to the 30.2km far from the beginning of up stream. The BOD concentrationdrop to 7mg/l and DO concentration reaerated back to 7.9mg/l respectively. This point is also the

Raganone WWTP facility which discharge municipal waste into water. Therefore it shows the

same result just like the Flint WWTP. Due to the velocity in this part is lower than river1 so the

Ka reaeration rate is lower and we can see the sag curve which take place at 45km downstream

form the beginning and DO concentration reach to 6.9mg/l .


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2.5 Impact and Suggestion

High organic concentration has highly impact on the water body especially it will consume DO

in water and lead to lower concentration which fish cannot survive in this critical situation. On

the figure7 most of the fish have to survive in water body which DO concentration higher than

6.5mg/l. As the figure 6 we saw in the 1.2km point source discharge, the DO concentration is

5mg/l which means in this segment fish cannot survive. So in order keep the DO concentration

higher than 6.5mg/l in this part, we have to add extra facilities on the down stream of Flint

WWTP. Air striping is a good way to increase the initial concentration of dissolved oxygen.

Figure 7 Demand of oxygen for different Biomass in river[4]

3

Modeling the sediment and heavy metal transport in flint river

3.1 Determining parameters

In order to model the heavy metal transport, the data required are river and waste water flow

rates and associated metal concentrations. The two waste water treatment systems are the largest


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source of metals in the study reach. Together with upstream contributions from the river, these

three sources ate assumed to comprise the total metal input to the system. Three priority

contaminants are Zinc, Copper and Cadmium.

In order to approach the model, several assumptions were made.

1) The river is at steady-state with respect to flow and loads;

2) Concentration of the modeled substance is uniform over the cross-section of the river (i.e., one

dimensional system); thus, any point discharge instantaneously mixes with the river flow at the

point of discharge;

3) Dispersion is negligible in the longitudinal direction; that is only advection is considered

significant in the direction of flow; thus, E = 0 in equation A4;

4) Flow, cross-sectional area, and mean depth are constant over the reach in question. 2

The model is chosen based on the two assumptions where, Kd2=Kd1=0, that is there is no

degradation or decay of metals in the sediment or water column. This assumption is quite

reasonable since most metals do not decay or otherwise degrade in exception of mercury which

can volatize. And the second one is that the partition coefficient of the metal in the water column

is not the same as the partition coefficient in the sediment column. Although the range of the

uncertainty on the partition coefficient is relatively high, the partition coefficient for suspended

and bedded sediments can differ since the characteristics of solids in the bed differ from the

water and generally lower. For these reasons and experimental data, the partition coefficient of

150,000 kg-1

was chosen. Based on the above assumptions, Level 2 interaction level was chosen

to model the flint river.

In addition to the flow rated and metal concentrations additional data and parameters have to be

either calculated by empirical equations or estimated. The typical river bottom will have a water

content between 60% to 95% by weight; therefore, if the solids have a specific gravity of 2.5, the

solid concentrations in the bed will vary from approximately 50,000-500,00 mg/L of bulk

sediment. Based on some sampling done by the study a value of m2=200,000 mg/L was chosen.

Since the August data is during a relatively low flow season, it is intuitive that the resuspension


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velocity is almost zero, however based one several studies it has been shown that this assumption

is true up to the Ragnone WWTP, however after km point 35 the resuspension could not be

ignored, therefore the value of 2.0 x 10-5 m/day was chosen as the resuspension velocity of the

whole section. 1,2

Partition coefficient of the metals were calculated based on the following formula:

"Kp(l/Kg)=K po . SSalpha

Where SS is the suspended solid concentration mg/l, and Kpo and Alpha are found from the

following table.

Table 7 Partition coefficient of priority pollutants

Metals Kpo in streams Alpha

Cadmium 4.00E+06 -1.13

Copper 1.04E+06 -0.74

Zinc 1.25E+06 -0.7

It is assumed that the partition coefficients remain constant through out the river.

The initial conditions for suspended solid concentration in the water column were calculated

using the formula shown below:

( ) !"

#

$%

&''+

(()

*

++,

-'= )exp(1exp

1

2

1

01 x

U H

V

V

m V x

U H

V m m

s

s

u s

Where Vs is the settling velocity, Vu is the resuspension velocity, H1 the depth of the river and

U is the velocity of the river at each segment. In this formula we used the assumption that the

dilution is almost instantaneous and there is no axial dispersion. The models were also based on

the above equation.


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All calculated parameters are shown in the table below.

Parameter Meaning Upstream Disch

arge1

Discharge2 Partition

Coefficient kgC_Zinc Concentration of Cr in

water column (ug/L)

7.70 55.00 60.15 2.00E

C-Cadmium Concentration of Cr in

water column (ug/L)

0.07 0.16 3.70 6.00E

C-Copper Concentration of Cr in

water column (ug/L)

2.90 8.30 34.80 2.10E

m1_SS Solid concentration in

water column (mg/L)

13.50 4.10 42.00

m2_SS Solid concentration in

sediment column (mg/L)

200,000 200,00

0

200,000

H2 Depth of sediment column

(m)

0.05

Kd2 Decay rate in sediment

column

0.0

Kp2 partition coefficient in bed 150,000

fd1 Fraction of dissolved xxx

in water column

0.91

Kp1 Partition coefficient in

water column (kg-1

)

200,000

!2 Sediment porosity 0.75

K f Sediment-water diffusive

transfer coefficient

(m/day)

0.027

Table 8 Concentration of heavy metals and parameters in each point discharge

Parameter Meaning Steady Conditions

fp2 Fraction of particle Cr in sediment column 0.0100000

Vs (m/day) Settling velocity 0.2500000

Vd (m/day) net sedimentation 0.0000114

Vu (m/day) Resuspension velocity 0.0000200

Vn (m/day)

Net loss of solids from the water column 0.0907643

" 0.7699018


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VTs (m/day) Loss due to sediment interaction 0.0010059

Table 9 parameters for level 2 analysis

3.2 Model Maker simulation

In order to simulate the transport of heavy metals, Model Maker has been used. The model

consists of two main components: The total concentration of heavy metal in the water column

and the suspended solid concentration in the water column. These two components can be

combined to predict the weight fraction of the heavy metal in the sediment.

The following equations were used in order to model the heavy metal and suspended solid

concentrations. And these two values can be combined to calculate r2 from the subsequent

formula.3

2

1

1

1

1m

H

V m

H

V

dx

dm U

u s +!=

24#$%

4+ & '

.$/

01 #$6

( )!!"

#

$$%

&''(

)**+

, -''(

)**+

,= x

U H

V

Q

W

m

f x r

T T p

11

1

2 exp.

where,

( ) ( )

( ) 222222

2

2

122

/

/

H f K f K f V V

f K f V V

d d d f p d u

d

f p d u

+++

++

=

!

! " "

#

Compartment Equation Initial value


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and Cadmium.

Figure 9 Model Maker 4 simulation

3.3 Results and Analysis

In general, for heavy metals the results can be somewhat predicted by finding out the value of

Kp.SS.10-6

. If Kp.SS.10-6

>>1 the metal is highly absorbed to the particulates in the water column

and the fate of the metals is directly proportional to the particulates and can be predicted by just

monitoring particulates, however when Kp.SS.10-6


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souring or settling period is higher for copper with higher partition coefficient and therefore

higher Kp.SS.10-6

value supporting our claim. Also Copper exists in more particulate form than

dissolved form comparing to zinc, therefore more subjected to settling and scouring. Overall, all

three priority pollutants are mostly in dissolved form with very minimal settling and scouring

showing that any metals entering the stream will exist in the dissolved form and dilution is the

governing factor in determining the concentration of these metals.

Since the concentration threshold of cadmium is much lower than copper and Zinc, Cadmium is

shown in different graphs.

Figure 10 Total concentration of heavy metal in the water column


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Figure 11 Total concentration of Cadmium in the water column

Figure 12 Weight fraction of heavy metals in the sediment column


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Figure 13 Cadmium weight fraction in the sediment column

Figure 14 Suspended solid concentration in the water column


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Figure 15 Weight of zinc and Copper in the sediment column

The maximum concentrations of metals are presented in the table below.

='44)%/$%2 L/H

D'$*1$%&/%+'$2P:9Q.R

7%/$(/&( 0'& 0+2E /$( /S)/%+*

4+01P:9Q.R

T+$* THTMP 6

D/(:+): THTTT7 THT7D'>>1& THTTO THTMTable 10 Maximum concentrations in the flint river vs standard

4 Conclusion and Mitigation strategies

As it can be seen from the previous sections, the river mostly meets the standards except from

dissolved oxygen which drops to around 5 mg/L shortly after the flint WWTP discharge.

However, as it can be seen from the initial conditions the DO upstream is low too, that is because

the the flint river above flint is in a polluted condition because of wastes from secondary

treatment plants of Lapeer and the Lapeer state home and training schools, and periodic

discharges of untreated wastes from the communities of North Branch and Columbiaville.

The severe oxygen depletion downstream from Flint was cause by the organic load to the river

although the secondary plant is operation at a high degree of efficiency.


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During the drought flow periods, the waste flow would equal to 90% of the river flow as can be

seen in the August survey. Under these conditions, even efficient secondary treatment results in

high concentrations of pollutants in the stream especially in conservative and semiconservative

wastes such as salts and nutrients which are little affected by present secondary treatment

methods. As a result, the flint river with 24% of the total Saginaw river flow, contributed 50% to

the total nutrient loading of the Saginaw river. The pollution load to the Flint river from this

highly developed area is in excess of the assimilative capacity of the stream with the present

degree of treatment. Moreover, the population of these areas are increasing therefore, the WWTP

has to take that into the account for preventive measures.

Although heavy metal concentrations meet the standards, Cadmium, Copper and Zinc tend to act

synergistically and when present at the same time will have lower thresholds as discussed in the

introduction. In order to mitigate the metal concentration and DO depletion in Flint river and

consequently in Saginaw river and the drainage area waste allocation program as to be done for

all industries and municipal discharges to the river. If higher population of these municipal areas

results in even higher DO depletion other methods such as aerators have to be installed in the

river in order to preserve the aquatic life of the river. A tertiary treatment system for flint and

Ragnone WWTPs can also be a good investment for preventive measures.


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References

[1] Federal Water Pollution Control Administration Great Lake Region “Lake Huron Basin.

Flint River –Michigan” 1965 Survey

[2] United States Environmental Protection Agency “Water Quality Assessment: A screeningProcedure for Toxic and Conventional Pollutants in Surface and Ground Water”

[3 ] Robert V. Thomann, John A. Mueller. Principles of Surface Water Quality Modeling and

Control[M]. Harper Collins Publishers, 1987: 1-637.

[4] United states Environmental Protection Agency “Ambient Water Quality Criteria forDissolved Oxygen”

[5] Flint river-Michigan-Water Quality Data- 1965 survey Clean water series DPO-13-C EPA

US department of the interior federal water pollution control administration.

[6] McKee J.E and H.W Wolf, 1963 “Water Quality Criteria”,2nd

ed. State water quality control

board of California.

[7] Schneider E. G. 1931 “Copper and Health” Jour NEWWA , Water pollustion Abs (sept 1931)

[8] Tarzwll C. M 1958 “Disposal of Toxic Wastes” Ind. Wastes 3:2 48

[9] Dourdoroff. P. M Kratz 1953, “Critical Review of Literature on the toxicity of industrial

wastes and thei components to Fish

Flint River- final report- environmental engineering

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