peter 5th year project presentation

EGERTON UNIVERSITYFACULTY OF ENGINEERING AND TECHNOLOGY

Department of Civil and Environmental Engineering

FINAL YEAR PROJECT PRESENTATION

TITLE:

STORM WATER RUNOFF QUALITY ASSESSMENT IN URBAN AREAS-CASE STUDY NAKURU CITY

BY:MURIGI PETER NJOROGE B12/40044/07

COURSE:BSC. WATER AND ENVIRONMENTAL ENGINEERING

DATE:22/05/2012

PROJECT SUPERVISOR:PROF TUITOEK

EGERTON UNIVERSITYFACULTY OF ENGINEERING AND TECHNOLOGY

Department of Civil and Environmental Engineering

FINAL YEAR PROJECT PRESENTATION

TITLE:

STORM WATER RUNOFF QUALITY ASSESSMENT IN URBAN AREAS-CASE STUDY NAKURU CITY

BY:MURIGI PETER NJOROGE B12/40044/07

COURSE:BSC. WATER AND ENVIRONMENTAL ENGINEERING

DATE:22/05/2012

PROJECT SUPERVISOR:PROF TUITOEK

ABSTRACT

According to recent global survey, Nakuru is the fastest growing town in East and CentralAfrica.

In spite of National Environmental Management Authority (NEMA) policies and otherregulations on pollution control being in place, the municipal council of Nakuru hasbeen lagging behind in enforcement of such laws and policies on proper environmentalmanagement practices.

Particularly pollution from stormwater runoff has been greatly ignored as it is directlydischarged without treatment to Lake Nakuru and thus the need for this study tohighlight the extent of this pollution.

The objective of this study was to determine pollutants contained in runoff and theirconcentrations from runoff samples collected in various sampling points in Nakuru:market , garage and industrial area.

Various methods were used in achieving the objectives such as A.A.S for analysis ofmetals, TP, open reflux method for COD and filtration for TSS.

The results showed high average levels of the parameters mentioned above i.e.TSS(1167mg/l) ,TP(2.43 mg/l), COD (207.57mg/l),Pb( 0.0283mg/l), Zn( 1.278mg/l).

The objective of this project was thus to determine the pollutants contained instormwater runoff and their concentrations.

The study further aimed at making recommendations on proper stormwater runoffpollution control to the municipal council of Nakuru, based on the observed deviation ofparameter values from KEBS effluent discharge standards.

According to recent global survey, Nakuru is the fastest growing town in East and CentralAfrica.

In spite of National Environmental Management Authority (NEMA) policies and otherregulations on pollution control being in place, the municipal council of Nakuru hasbeen lagging behind in enforcement of such laws and policies on proper environmentalmanagement practices.

Particularly pollution from stormwater runoff has been greatly ignored as it is directlydischarged without treatment to Lake Nakuru and thus the need for this study tohighlight the extent of this pollution.

The objective of this study was to determine pollutants contained in runoff and theirconcentrations from runoff samples collected in various sampling points in Nakuru:market , garage and industrial area.

Various methods were used in achieving the objectives such as A.A.S for analysis ofmetals, TP, open reflux method for COD and filtration for TSS.

The results showed high average levels of the parameters mentioned above i.e.TSS(1167mg/l) ,TP(2.43 mg/l), COD (207.57mg/l),Pb( 0.0283mg/l), Zn( 1.278mg/l).

The objective of this project was thus to determine the pollutants contained instormwater runoff and their concentrations.

The study further aimed at making recommendations on proper stormwater runoffpollution control to the municipal council of Nakuru, based on the observed deviation ofparameter values from KEBS effluent discharge standards.

CHAPTER ONEINTRODUCTION

Storm water runoff occurs when precipitation from rain flows over theground. Impervious surfaces like driveways, sidewalks, and streetspreventing storm water runoff from naturally infiltrating into theground. It picks up debris, chemicals, dirt, and other pollutants andflow into a storm sewer system or directly to a lake, stream, river,wetland, or coastal water. Anything that enters a storm sewer systemis discharged untreated into the water bodies we use for swimming,fishing and providing drinking water.The main reason why urban storm water remains such an importantcontributor to water pollution is the fact that in most areas, stormwater receives no treatment before entering water bodies.

INTRODUCTIONStorm water runoff occurs when precipitation from rain flows over theground. Impervious surfaces like driveways, sidewalks, and streetspreventing storm water runoff from naturally infiltrating into theground. It picks up debris, chemicals, dirt, and other pollutants andflow into a storm sewer system or directly to a lake, stream, river,wetland, or coastal water. Anything that enters a storm sewer systemis discharged untreated into the water bodies we use for swimming,fishing and providing drinking water.The main reason why urban storm water remains such an importantcontributor to water pollution is the fact that in most areas, stormwater receives no treatment before entering water bodies.

STATEMENT OF THE PROBLEM

Storm water runoff is designated as aleading impairment source for estuaries andthe third largest pollution source for lakesand rivers. Yet, it has remained the mostignored source of pollution by manymunicipals in the world.

Storm water runoff is designated as aleading impairment source for estuaries andthe third largest pollution source for lakesand rivers. Yet, it has remained the mostignored source of pollution by manymunicipals in the world.

JUSTIFICATION

Due to increasing areas of impervious surfaces as roads,parking lots, and rooftops in urbanized locations, a greaterfraction of precipitation cannot infiltrate into the soil andbecomes runoff, mobilizing deposited pollutants. It containssuspended solids (SS), heavy metals, phosphorus (P), nitrates,and other harmful pollutants.

Increases in the variety and concentrations of pollutantsmobilized in the runoff deleteriously impact water quality andthe viability of surrounding ecosystems, in addition toincreasing subsequent water treatment costs. Therefore theneed for analysis of contaminants in runoff as a pre requisitefor recommendation of better water management practices.

Due to increasing areas of impervious surfaces as roads,parking lots, and rooftops in urbanized locations, a greaterfraction of precipitation cannot infiltrate into the soil andbecomes runoff, mobilizing deposited pollutants. It containssuspended solids (SS), heavy metals, phosphorus (P), nitrates,and other harmful pollutants.

Increases in the variety and concentrations of pollutantsmobilized in the runoff deleteriously impact water quality andthe viability of surrounding ecosystems, in addition toincreasing subsequent water treatment costs. Therefore theneed for analysis of contaminants in runoff as a pre requisitefor recommendation of better water management practices.

GENERAL OBJECTIVE

To determine pollutants contained in stormwater runoff of paved surfaces in Nakurutown.

To determine pollutants contained in stormwater runoff of paved surfaces in Nakurutown.

SPECIFIC OBJECTIVES

To determine the amount ofCOD, TSS, TP, Pb, Fe, Zn, Mn contained in stormwater runoff. To determine whether the concentrations of the

above parameters in runoff exceed the effluentdischarge standards. To propose best stormwater runoff management

practices based on the results obtained.

To determine the amount ofCOD, TSS, TP, Pb, Fe, Zn, Mn contained in stormwater runoff. To determine whether the concentrations of the

above parameters in runoff exceed the effluentdischarge standards. To propose best stormwater runoff management

practices based on the results obtained.

HYPOTHESIS

Storm water runoff in Nakuru towncontributes to water pollution in LakeNakuru and other adjacent water bodies.

Storm water runoff in Nakuru towncontributes to water pollution in LakeNakuru and other adjacent water bodies.

LITERATURE REVIEW

The impacts of storm water pollutionThe storm water pollution problem has two maincomponents: The increased volume and velocity of surface

runoff. The concentration of pollutants in the runoff.

The impacts of storm water pollutionThe storm water pollution problem has two maincomponents: The increased volume and velocity of surface

runoff. The concentration of pollutants in the runoff.

Components of Storm water Pollution

1] Increased Volume And Velocity due to The Impervious Cover Factor

a)Types of Impervious CoverSome impervious cover, such as exposed rock or hardpan soil, is natural. Landdevelopment, however, greatly increases it. Human-made impervious cover comesin three varieties: rooftop imperviousness from buildings and other structures;transport imperviousness from roadways, parking lots, and other transportation-related facilities; and impaired pervious surfaces, also known as urban soils, whichare natural surfaces that become compacted or otherwise altered and less perviousthrough human action.

b) Imperviousness ThresholdsAs the amount of impervious surface in a watershed increases, infiltration andevapotranspiration both drop substantially. As a result, more water, having nowhereelse to go, runs off the surface picking up pollutants from activities occurring on theimpervious surfaces.

1] Increased Volume And Velocity due to The Impervious Cover Factor

a)Types of Impervious CoverSome impervious cover, such as exposed rock or hardpan soil, is natural. Landdevelopment, however, greatly increases it. Human-made impervious cover comesin three varieties: rooftop imperviousness from buildings and other structures;transport imperviousness from roadways, parking lots, and other transportation-related facilities; and impaired pervious surfaces, also known as urban soils, whichare natural surfaces that become compacted or otherwise altered and less perviousthrough human action.

b) Imperviousness ThresholdsAs the amount of impervious surface in a watershed increases, infiltration andevapotranspiration both drop substantially. As a result, more water, having nowhereelse to go, runs off the surface picking up pollutants from activities occurring on theimpervious surfaces.

c) Increased Volume of Runoff The effect of impervious surfaces on the volume of storm water

runoff can be dramatic. For example, a 1-inch rainstorm on a 1-acrenatural meadow would typically produce 218 cubic feet ofrunoff, enough to fill a standard size office to a depth of about 2 feet.

The same storm over a 1-acre paved parking lot would produce3,450 cubic feet of runoff, nearly 16 times more than the naturalmeadow, and enough to fill three standard size offices completely.On a larger scale, the effect is even greater.

d) Greater Stream and Runoff Velocity DuringStorm Events

Unlike grassy meadows or forests, hard, impervious cover, suchas parking lots and rooftops, offers little resistance to water flowingdownhill, allowing it to travel faster along these surfaces.

The increased velocity and delivery rate greatly magnifies theerosive power of water as it flows across the land surface and once itenters a stream.

c) Increased Volume of Runoff The effect of impervious surfaces on the volume of storm water

runoff can be dramatic. For example, a 1-inch rainstorm on a 1-acrenatural meadow would typically produce 218 cubic feet ofrunoff, enough to fill a standard size office to a depth of about 2 feet.

The same storm over a 1-acre paved parking lot would produce3,450 cubic feet of runoff, nearly 16 times more than the naturalmeadow, and enough to fill three standard size offices completely.On a larger scale, the effect is even greater.

d) Greater Stream and Runoff Velocity DuringStorm Events

Unlike grassy meadows or forests, hard, impervious cover, suchas parking lots and rooftops, offers little resistance to water flowingdownhill, allowing it to travel faster along these surfaces.

The increased velocity and delivery rate greatly magnifies theerosive power of water as it flows across the land surface and once itenters a stream.

e) Increased Peak Discharges

Greater peak flows lead to increasedflooding, channel erosion andwidening, sediment deposition, bankcutting, and general habitat loss.

f) Reduced Stream Base Flow

Because impervious cover reduces infiltrationand forces storm water to run off the landimmediately, it also typically reduces theamount of groundwater available to rechargestreams when there is no rain.

e) Increased Peak Discharges

Greater peak flows lead to increasedflooding, channel erosion andwidening, sediment deposition, bankcutting, and general habitat loss.

f) Reduced Stream Base Flow

Because impervious cover reduces infiltrationand forces storm water to run off the landimmediately, it also typically reduces theamount of groundwater available to rechargestreams when there is no rain.

g) Decreased Natural Storm water PurificationFunctions

Channelizing, diking, and levyingdisconnect a river from its floodplain andreduce its ability to modify floods naturally. Eliminating the natural drainage ways

reduces flow storage and detention and soilmoisture maintenance and can increaseoverall flooding and erosion.

g) Decreased Natural Storm water PurificationFunctions

Channelizing, diking, and levyingdisconnect a river from its floodplain andreduce its ability to modify floods naturally. Eliminating the natural drainage ways

reduces flow storage and detention and soilmoisture maintenance and can increaseoverall flooding and erosion.

Categories of Principal Contaminants in Stormwater

Category Examples

2] Increased Deposition Of PollutantsThe second aspect of urbanization that contributes to urbanstorm water pollution is the increased discharge ofpollutants. As human activity increases in a given area, theamount of waste material deposited on the land and indrainage systems increases. The principal contaminants ofconcern for storm water fall into seven categories.

Category Examples

Metals zinc, cadmium, copper, chromium, arsenic, lead

Organic chemicals pesticides, oil, gasoline, grease

Pathogens viruses, bacteria, protozoa

Nutrients nitrogen, phosphorus

Biochemical oxygen demand (BOD) grass clippings, fallen leaves, hydrocarbons, human, and animal waste

Sediment sand, soil, and silt

Salts sodium chloride, calcium chloride

Contributors of stormwater pollution

a) Vehicle Useb) Roads and Parking Lotsc) Home Landscaping and Public Grounds

Maintenanced) Construction Sitese) Illicit Sanitary Connections to Storm Sewers From

Homes and Businessesf) Septic Systemsg) Illicit Industrial Connections to Storm Sewersh) Uncovered Materials Stored Outsidei) Landfillsj) Pets and Domestic Animals

a) Vehicle Useb) Roads and Parking Lotsc) Home Landscaping and Public Grounds

Maintenanced) Construction Sitese) Illicit Sanitary Connections to Storm Sewers From

Homes and Businessesf) Septic Systemsg) Illicit Industrial Connections to Storm Sewersh) Uncovered Materials Stored Outsidei) Landfillsj) Pets and Domestic Animals

CURRENT RESEARCH CONDUCTED ONSTORMWATER RUNOFF

A) Nationwide Urban Runoff Program (NURP) research

In 1978, the U.S. Environmental Protection Agency (EPA) initiated theNationwide Urban Runoff Program (NURP) to quantify the characteristics ofurban runoff, assess the impacts of urban runoff on the water quality ofreceiving waters, and examine the effectiveness of control practices inremoving pollutants found in urban runoff. An average of 28 storms for each ofthe 81 representative outfalls in 28 metropolitan areas was monitored from1978 to 1983 (U.S. EPA, 1999b).

Ten pollutants, includingTSS, BOD, COD, TP, SP, TKN, nitrate/nitrite, Total Cu, total Pb, and totalZn, will be selected being monitored by NURP. The water quality of untreatedurban runoff and domestic wastewater was compared and summarized in Table1 (U.S. EPA, 1999b).

It also showed the loadings of pollutants from urban runoff can be muchhigher than the ones from treated domestic wastewater.

A) Nationwide Urban Runoff Program (NURP) research

In 1978, the U.S. Environmental Protection Agency (EPA) initiated theNationwide Urban Runoff Program (NURP) to quantify the characteristics ofurban runoff, assess the impacts of urban runoff on the water quality ofreceiving waters, and examine the effectiveness of control practices inremoving pollutants found in urban runoff. An average of 28 storms for each ofthe 81 representative outfalls in 28 metropolitan areas was monitored from1978 to 1983 (U.S. EPA, 1999b).

Ten pollutants, includingTSS, BOD, COD, TP, SP, TKN, nitrate/nitrite, Total Cu, total Pb, and totalZn, will be selected being monitored by NURP. The water quality of untreatedurban runoff and domestic wastewater was compared and summarized in Table1 (U.S. EPA, 1999b).

It also showed the loadings of pollutants from urban runoff can be muchhigher than the ones from treated domestic wastewater.

Comparison of Water Quality Parameters in Urban Runoff withdomestic Wastewater(U.S.EPA.1999b)

B) Quality Of Storm Water Runoff From Urbanized HoustonMetropolitan Area (Min Chu, P.E.)

During the years 1992 and 1993, the City of Houston the City of Pasadena conductedrepresentative storm water sampling from a total of 15 sites located in the urbanized Houstonmetropolitan area. The storm water sampling effort was in response to the U. S.Environmental Protection Agency (EPA) storm water NPDES permitting requirements for thefollowing four land-use categories:• Single-family residential.• Multi-family residential.• Commercial.• Industrial.

Three different sites from each land-use category were chosen for representative samplingpurposes. Three additional sites where drainage areas were primarily undeveloped also wereselected to establish baseline water quality conditions.

The primary purpose of the sampling was to determine the event mean concentrations (EMC)of storm water runoff from each of the five unique land use categories. The EMCs weresubsequently used to estimate annual pollutant loads from each major watershed.

For representative sampling, the storm should have a volume greater than 0.1 inch, should bepreceded by at least 72 hours of dry weather, and should not vary by more than 50 percentfrom the average rainfall volume and duration, where feasible.

During the years 1992 and 1993, the City of Houston the City of Pasadena conductedrepresentative storm water sampling from a total of 15 sites located in the urbanized Houstonmetropolitan area. The storm water sampling effort was in response to the U. S.Environmental Protection Agency (EPA) storm water NPDES permitting requirements for thefollowing four land-use categories:• Single-family residential.• Multi-family residential.• Commercial.• Industrial.

Three different sites from each land-use category were chosen for representative samplingpurposes. Three additional sites where drainage areas were primarily undeveloped also wereselected to establish baseline water quality conditions.

The primary purpose of the sampling was to determine the event mean concentrations (EMC)of storm water runoff from each of the five unique land use categories. The EMCs weresubsequently used to estimate annual pollutant loads from each major watershed.

For representative sampling, the storm should have a volume greater than 0.1 inch, should bepreceded by at least 72 hours of dry weather, and should not vary by more than 50 percentfrom the average rainfall volume and duration, where feasible.

RESEARCH METHODOLOGY

Apparatus Spectrophotometer(AAS-S11). UV 200-RS Photometer. In relation to A.A.S, this device is used for the qualitative and

quantitative determination of chemical elements employing theabsorption of optical radiation in free atoms in gaseous state. In orderto analyse a sample for its atomic constituents it has to be atomized.The most commonly used atomizer is the air-acetylene flame at atemperature of 23000C. This technique relates the measuredabsorbance with the analyte concentration using Beer-Lambert Law.(www.wikipedia.org/wiki/Spectrophotometer)

Test tubes and beakers Cathode lamp Oven Filter papers

Apparatus Spectrophotometer(AAS-S11). UV 200-RS Photometer. In relation to A.A.S, this device is used for the qualitative and

quantitative determination of chemical elements employing theabsorption of optical radiation in free atoms in gaseous state. In orderto analyse a sample for its atomic constituents it has to be atomized.The most commonly used atomizer is the air-acetylene flame at atemperature of 23000C. This technique relates the measuredabsorbance with the analyte concentration using Beer-Lambert Law.(www.wikipedia.org/wiki/Spectrophotometer)

Test tubes and beakers Cathode lamp Oven Filter papers

Chemicals Used Acetylene gas Mercury sulphate Dichromate Conc. Sulphuric acid Ferroin indicator Potassium hydrogen Phosphate (KH2PO4) Potassium Sulphate (K2SO4) Phenolphthalein indicator Sodium hydroxide Isopropanol

Acetylene gas Mercury sulphate Dichromate Conc. Sulphuric acid Ferroin indicator Potassium hydrogen Phosphate (KH2PO4) Potassium Sulphate (K2SO4) Phenolphthalein indicator Sodium hydroxide Isopropanol

Analytical Methods

Heavy metals (Pb, Mn, Fe, and Zn)Analysis (Willard et al, 1986)

Pb were analyzed on the atomic absorption spectrophotometer. Pbstandards of 0,1.0,2.0, 3.0 and 4.0mg/l were prepared from 1000 mg/L .

A cathode lamp were used at a known wavelength (nm), band pass(nm) and lamp current of milliamps, as shown below. To analyze,samples were acidified using acetylene gas, filtered, and then analyzedon an AAS-S11 Photometer.

Similar test were carried out on Mn, Fe, and Zn and concentrationcurves drawn using the graph of concentration against absorbance theconcentration were got using the formula:

Y=mx Where y-concentration in mg/l M-gradient X-absorption

Heavy metals (Pb, Mn, Fe, and Zn)Analysis (Willard et al, 1986)

Pb were analyzed on the atomic absorption spectrophotometer. Pbstandards of 0,1.0,2.0, 3.0 and 4.0mg/l were prepared from 1000 mg/L .

A cathode lamp were used at a known wavelength (nm), band pass(nm) and lamp current of milliamps, as shown below. To analyze,samples were acidified using acetylene gas, filtered, and then analyzedon an AAS-S11 Photometer.

Similar test were carried out on Mn, Fe, and Zn and concentrationcurves drawn using the graph of concentration against absorbance theconcentration were got using the formula:

Y=mx Where y-concentration in mg/l M-gradient X-absorption

Chemical oxygen demand Analysis (Willard etal, 1986)

A sample from each source, of 50cc was put into a quick-fit flask.A standard solution of distilled water was prepared alongside.The quick fit flasks were then placed on a heating mantle. Toeach, 1g of Mercury (II) Sulphate and 5cc of dichromate wereadded to digest the sample. 75ml of conc. sulphuric acid wereadded. Condensers were then connected on the fit-in flasks.

The samples were refluxed for 2hrs and left to cool then 3 dropsof ferroin indicator were added to determine the endpointduring titration.

Titration were done using FAS of molarity as 0.284M. Theendpoints of the titrations were recorded as follows

COD= ((A-B)/vol of sample)*molarity*8000 A-endpoint of blank sample in ml B-endpoint of sample in ml

A sample from each source, of 50cc was put into a quick-fit flask.A standard solution of distilled water was prepared alongside.The quick fit flasks were then placed on a heating mantle. Toeach, 1g of Mercury (II) Sulphate and 5cc of dichromate wereadded to digest the sample. 75ml of conc. sulphuric acid wereadded. Condensers were then connected on the fit-in flasks.

The samples were refluxed for 2hrs and left to cool then 3 dropsof ferroin indicator were added to determine the endpointduring titration.

Titration were done using FAS of molarity as 0.284M. Theendpoints of the titrations were recorded as follows

COD= ((A-B)/vol of sample)*molarity*8000 A-endpoint of blank sample in ml B-endpoint of sample in ml

Total suspended solids analysis (Sharma BK, 2004)

A filter paper were weighed and recorded as(B) in grams ,then three samples 100ml werefiltered through the filter papers then driedat 105o c for 2hrs. After drying weight wererecorded as (A) in grams.Tss=(B-A/vol of sample in ml)*1000

A filter paper were weighed and recorded as(B) in grams ,then three samples 100ml werefiltered through the filter papers then driedat 105o c for 2hrs. After drying weight wererecorded as (A) in grams.Tss=(B-A/vol of sample in ml)*1000

Total Phosphorous (Sharma B K, 2004)Preparation of standard solution

Phosphate buffer solution (pH 3.4) was prepared by dissolving 5.04 g of disodium hydrogenphosphate and 3.01 g of potassium Dihydrogen phosphate in water and made upto 1000 mL.

Stock solution (1 mg/1 mL) 100 mg of the sample stormwater was accurately weighed and transferred into 100 mL

volumetric standard flask and added phosphate buffer and made up to100 mL with phosphate buffer.

Bromothymol blue solution 50 mg of bromothymol blue was dissolved in 4 mL of 0.02 M NaOH and 20 mL of ethanol

(95%). After solution is effected, sufficient water was added and made upto 100 mL.

Absorption spectra for drug in bromothymol blue From the stock solution, 10 mL was taken and added with 1 mL of bromothymol blue and it

was diluted with 500 mL of phosphate buffer to make the concentration 200 g/mL. Theabsorbance of the solution was measured with a wavelength of 880 nm in a UV 200-RS spectrophotometer.

A representative sample from each standard and sample were analysed and results tabulated thenconcentration curves (A graph of concentration against absorbance) were used to compute results using theformula below).Y=mxWhere y-concentration in mg/lM-gradientX-absorption

Preparation of standard solution Phosphate buffer solution (pH 3.4) was prepared by dissolving 5.04 g of disodium hydrogen

phosphate and 3.01 g of potassium Dihydrogen phosphate in water and made upto 1000 mL.

Stock solution (1 mg/1 mL) 100 mg of the sample stormwater was accurately weighed and transferred into 100 mL

volumetric standard flask and added phosphate buffer and made up to100 mL with phosphate buffer.

Bromothymol blue solution 50 mg of bromothymol blue was dissolved in 4 mL of 0.02 M NaOH and 20 mL of ethanol

(95%). After solution is effected, sufficient water was added and made upto 100 mL.

Absorption spectra for drug in bromothymol blue From the stock solution, 10 mL was taken and added with 1 mL of bromothymol blue and it

was diluted with 500 mL of phosphate buffer to make the concentration 200 g/mL. Theabsorbance of the solution was measured with a wavelength of 880 nm in a UV 200-RS spectrophotometer.

A representative sample from each standard and sample were analysed and results tabulated thenconcentration curves (A graph of concentration against absorbance) were used to compute results using theformula below).Y=mxWhere y-concentration in mg/lM-gradientX-absorption

Data collectionSelection of suitable sites

Various sites were located according to susceptibility to occurrence ofpollutants.

A total of three monitoring sites were selected within the Nakuru townto represent the range of paved conditions and different types ofpollution concentration and variation. These sites were: a fuelstation, market place and industrial area.

Collection of samples Grab sampling were conducted from a storm event that produced a

discharge that were preceded by at least 72 hours of dry weather.Collection were done during the first hour of downpour to ensure thatthe first flush of runoff were taken as the representative sample.

The water quality samples were collected at the edge of pavements as itis a collection point, to represent untreated runoff.

Selection of suitable sites Various sites were located according to susceptibility to occurrence of

pollutants. A total of three monitoring sites were selected within the Nakuru town

to represent the range of paved conditions and different types ofpollution concentration and variation. These sites were: a fuelstation, market place and industrial area.

Collection of samples Grab sampling were conducted from a storm event that produced a

discharge that were preceded by at least 72 hours of dry weather.Collection were done during the first hour of downpour to ensure thatthe first flush of runoff were taken as the representative sample.

The water quality samples were collected at the edge of pavements as itis a collection point, to represent untreated runoff.

Site Map

RESULTS AND ANALYSISThe sample collected (composite samplefrom the 3 sampling points) was a controlsample to identify the presence of theselected parameters if they were present inthe sampling points selected. Resultsshowed their levels as below:

The sample collected (composite samplefrom the 3 sampling points) was a controlsample to identify the presence of theselected parameters if they were present inthe sampling points selected. Resultsshowed their levels as below:

ElementStormwaterconcentration(mg/L)

effluent dischargestandards

TSS 1167 30TP 2.43 2COD 207.57 50Pb 0.0283 0.01Fe 2.077 3Zn 1.278 0.5Mn 3.122 10

Table 1 Results for composite sample

COMPOSITE SAMPLE ANALYSIS

10000

Comparison between concetrations with effluent dischargestandards

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TSS TP COD Pb Fe Zn MnCon

cent

rati

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Element

Stormwaterconcentration(mg/L)


Figure 1 Comparison between concentrations with effluent discharge standards

Most parameters proved positive and were above effluent discharge standards as shownin the graph above.

COMPARATIVE SAMPLING RESULTSThese samples were taken at 3 different sites to investigate the variation of concentration in the selected sites.

MARKET

Element Stormwater concentration(mg/L) effluent discharge standardsTSS 900 30TP 0.305 2

COD 224 50

Pb 0.02 0.01

Fe 1.15 3

Zn 1.4 0.5

Mn 1.58 10

Table 2 Results for market sample

Mn 1.58 10

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TSS TP COD Pb Fe Zn Mn

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Element

Comparison between Market concetration with effluent dischargestandards


effluent discharge standards

Figure 2 Comparison between concentrations with effluent dischargestandards

GARAGE

Element



TSS 1700 30TP 1.92 2

COD 344.96 50Pb 0.025 0.01Fe 4.55 3Zn 1.68 0.5Mn 2.36 10


Comparison between garage concetrations witheffluent discharge standards

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Comparison between garage concetrations witheffluent discharge standards




INDUSTRIAL AREA

Element Stormwater concentration(mg/L) effluent discharge standardsTSS 900 30TP 2.33 2

COD 53.76 50Pb 0.04 0.01Fe 0.53 3Zn 0.755 0.5Mn 5.4275 10


Comparison between industrial area concetrations with effluentdischarge standards


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Comparison between industrial area concetrations with effluentdischarge standards


effluent discharge standards

COMPARISON WITH EFFLUENT STANDARDS

Element

Stormwater concentration(mg/L)Effluent discharge

standardsIndustrial Area Market Garage Average

TSS 900 900 1700 1167 30TP 2.33 0.305 1.92 2.43 2

COD 53.76 224 344.96 207.57 50Pb 0.04 0.02 0.025 0.0283 0.01Fe 0.53 1.15 4.55 2.077 3Zn 0.755 1.4 1.68 1.278 0.5Mn 5.4275 1.58 2.36 3.122 10


0.01

Comparison Between Average and Effluent Discharge Standards


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Element

Stormwater concentration(mg/L)Average

Effluent discharge standards

DISCUSSION

Market The considerable amount of Pb, Zn, Mn and Fe at the

market was attributed to worn-out galvanisedrooftops, gutters which had been washed by stormwater. Asignificant amount of these may have been contributed byoutdoor storage of scrap metals. Poorly managed construction sites were a major source of

T.S.S at the market area. Phosphorus content was wellwithin the safety region of emission. Residual food wastes from cans/bottles, anti-freeze and

emulsified oils contributed a significant amount of COD.

Market The considerable amount of Pb, Zn, Mn and Fe at the

market was attributed to worn-out galvanisedrooftops, gutters which had been washed by stormwater. Asignificant amount of these may have been contributed byoutdoor storage of scrap metals. Poorly managed construction sites were a major source of

T.S.S at the market area. Phosphorus content was wellwithin the safety region of emission. Residual food wastes from cans/bottles, anti-freeze and

emulsified oils contributed a significant amount of COD.

Garage Amounts of Pb and Zinc were significantly above the KEBS

effluent emission standards, largely due to excessive vehicleexhausts, worn-out brake linings, tyre and engine wear.Lead was mainly from petroleum products and lubricants. TSS value was also quite high compared to the

standards, due to car wash activities. The sample containedfilterable particles of dust and traces of metallic elements. Total phosphorous was found to be high in carwash than

other points; this was due to detergents used in the carwashing. Discarded automotive batteries in the garage area also

contributed significantly to the presence of Pb and Zn inthe sample.

Amounts of Pb and Zinc were significantly above the KEBSeffluent emission standards, largely due to excessive vehicleexhausts, worn-out brake linings, tyre and engine wear.Lead was mainly from petroleum products and lubricants. TSS value was also quite high compared to the

standards, due to car wash activities. The sample containedfilterable particles of dust and traces of metallic elements. Total phosphorous was found to be high in carwash than

other points; this was due to detergents used in the carwashing. Discarded automotive batteries in the garage area also

contributed significantly to the presence of Pb and Zn inthe sample.

Industrial Area Assemblage of metal parts, air

emissions, smelter, paints were notable majorcausative source of presence of higher-than-standardvalues of Zn and Pb.

The high TSS value could be attributed to poor storageand disposal of waste residues, causing them to bewashed away into the stormwater drain wheneverthere is a downpour.

Assemblage of metal parts, airemissions, smelter, paints were notable majorcausative source of presence of higher-than-standardvalues of Zn and Pb.

The high TSS value could be attributed to poor storageand disposal of waste residues, causing them to bewashed away into the stormwater drain wheneverthere is a downpour.

CONCLUSION

The assessment was a success as the respective objectiveswere achieved i.e. most parameters tested were above themaximum permissible limit as per effluent dischargestandards in the third schedule. The three sampling points showed variation of pollutant

concentration and thus highlighted the sources ofpollution in runoff. Results showed that runoff has a variety of pollutants;

TSS, TP, COD, Zn, Pb, Mn and Fe. These pollutants posedanger to our water resources and therefore treatment isnecessary in order to conserve our water resources.

CHAPTER FIVE

The assessment was a success as the respective objectiveswere achieved i.e. most parameters tested were above themaximum permissible limit as per effluent dischargestandards in the third schedule. The three sampling points showed variation of pollutant

concentration and thus highlighted the sources ofpollution in runoff. Results showed that runoff has a variety of pollutants;

TSS, TP, COD, Zn, Pb, Mn and Fe. These pollutants posedanger to our water resources and therefore treatment isnecessary in order to conserve our water resources.

RECOMMENDATIONS Source controls- this involves regulation of the amount and rate of

runoff from impervious areas i.e. good drainage systems Treatment control approaches– these are designed to remove

pollutants from the runoff i.e. bio retention systems.A common collector runoff system, fitted with proper treatmentsystem and filtration mechanism, ought to be put in place so as toachieve significant control against downstream pollution, mainly byhuge TSS and COD values other than Zn and Pb.

Pollution prevention practices–These serve to keep chemicalsaway from rainfall and/or runoff e.g. collection and better disposalof litter. The industries, notably maize millers, Pesticideproducers, Agricultural machinery assembly lines e.t.c, in Nakurutown, ought to be vetted by the municipal sanitary department tocurtail possibilities of continuous discharge of uncontrolled andillegal untreated effluents into the stormwater drain.

Source controls- this involves regulation of the amount and rate ofrunoff from impervious areas i.e. good drainage systems

Treatment control approaches– these are designed to removepollutants from the runoff i.e. bio retention systems.A common collector runoff system, fitted with proper treatmentsystem and filtration mechanism, ought to be put in place so as toachieve significant control against downstream pollution, mainly byhuge TSS and COD values other than Zn and Pb.

Pollution prevention practices–These serve to keep chemicalsaway from rainfall and/or runoff e.g. collection and better disposalof litter. The industries, notably maize millers, Pesticideproducers, Agricultural machinery assembly lines e.t.c, in Nakurutown, ought to be vetted by the municipal sanitary department tocurtail possibilities of continuous discharge of uncontrolled andillegal untreated effluents into the stormwater drain.

REFERENCESAllen P. Davis, Ph.D., P.E. ,2003, Standards for Effluent Discharge RegulationsGeneral Notice No.44.of 2003, Department of Civil and EnvironmentalEngineering, University of Maryland College Park, MD 20742.

Kenya Environmental Management and Co-Ordination (Waste Management) Regulations,2006

Klein, Richard, D., 1979.Urbanization and Stream Quality Impairment," Water ResourcesBulletin.

NRDC's (Natural Resources Defense Council),1999, online newsletter

Min Chu, P.E. ,1993, Quality of Storm Water Runoff from Urbanized HoustonMetropolitan Area, Turner Collie & Braden Inc., USA

Schueler, T. R, 1995. Site Planning for Urban Stream Protection, MetropolitanWashington Council of Governments.

www.georgiastormwater.comwww.wikipedia.org/wiki/Spectrophotometer

Allen P. Davis, Ph.D., P.E. ,2003, Standards for Effluent Discharge RegulationsGeneral Notice No.44.of 2003, Department of Civil and EnvironmentalEngineering, University of Maryland College Park, MD 20742.

Kenya Environmental Management and Co-Ordination (Waste Management) Regulations,2006

Klein, Richard, D., 1979.Urbanization and Stream Quality Impairment," Water ResourcesBulletin.

NRDC's (Natural Resources Defense Council),1999, online newsletter

Min Chu, P.E. ,1993, Quality of Storm Water Runoff from Urbanized HoustonMetropolitan Area, Turner Collie & Braden Inc., USA

Schueler, T. R, 1995. Site Planning for Urban Stream Protection, MetropolitanWashington Council of Governments.

www.georgiastormwater.comwww.wikipedia.org/wiki/Spectrophotometer

APPENDICES

Picture 1: Sampling point-Nakuru MarketPictures

Picture 2: Weighing Balance

Picture 5 & 6: AAS-S11 Spectrophotometer and its Gascylinders

Picture 7: Carrying out COD test

LET’S MAKE NAKURU TOWNAND AFRICA A TIDIER PLACE

TO LIVE IN!

THANK YOU FOR YOURATTENTION!

LET’S MAKE NAKURU TOWNAND AFRICA A TIDIER PLACE

TO LIVE IN!

THANK YOU FOR YOURATTENTION!

peter 5th year project presentation

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