EXECUTIVE SUMMARY
The primary objective of collection and waste water treatment is to ensure that the effluent that is
discharged to the environment does not pose unexceptable risks to the health of humans and the
ecosystem.
Potchefstroom and the Mooiriver have been synonym for many years. The symbiotic co-existance
of a community and a river can be traced back to the late 1890’s and the early 1900’s. An irrigation
scheme were officially proclaimed by 1904. The river supplied a livelihood for many generations of
farmers and was most probably the prime reason for the settlement of ‘trekkers” in the area. Not
only did the river supply, but is still the sole source of drinking water for the community of
Potchefstroom. This fact was recognised by the elders of Potchefstroom and Potchefstroom was
equiped with the second activated sludge plant in the world that was designed to remove both
phosphates and nitrogen. An innovative Polishing plant was also constructed in 1979 to remove
phosphates.
In the 1990’s urbanisation step up to a level where it was soon recognised that the capacity of the
Waste water treatment Works would not be able to treat the ever increasing load of raw sewage
that was conveyed to the plant from all the serviced plots at an increasing rate. Another extention of
22 Mega Liter was added to the already exisitng 23 Mega liter capacity and were completed by
2002. The reactors were designed to either be used in a Phoredox or a UCT mode. This extension
made it possible to treat the flow of sewage, everyday of the year to a level that effluent discharged
to the river has the least impact on the environment.
The early 1950 saw the changing of the Wonderfonteinspruit forever. Mines with associated mining
communities rose in the whole upper catchment to impact on the quality of water that moved down
to Potchefstroom. Westonaria, Merafong were added to the already polluting Mogale city and
Randfontein with their mines and sewage plants.
As keepers of the environment Tlokwe Local Municipality started an extensive monitoring
programme on the catchment in 2002 and in the treatment of our sewage and discharge to the
cathment our endevour is to always put the environement first. We strive for excelence in the
treatment of our sewage and try to leave the smallest footprint possible in the catchment. In this
way we hope our co-existance, river and community will continue for years to come.
-
1-
1.
DESCRIPTION OF WASTE WATER TREATMENT WORKS
DESCRIPTION
PURPOSE
Raw sewage outfall
Transport raw sewage from three main
sewagelines to the new inlet works. The lines
serve the industrial area and all residential and
business areas.
Screening of raw sewage
The incoming sewage pass through one coarse
hand rake screen onto a mechanical front raked
fine screen. Two emergency hand rake screens
are available. Plastics, cotton and other nonfecal waste are seperated from the main
sewage stream, pressed by a sewer press and
presented for incineration or disposal.
Grit removal
Two vortex grit removal systems degrid sewage.
Sewage then flow into a pumping chamber. A
grid classifier dewater grit and deposit grit in a
bin.
Screened sewage delivery to Plants
Sewage is devided between new Plant,
Badenpho and Polishing Plant. Delivery to
Badenpho and Polishing Plant by pumps with
variable speed motors.
Primary settling of sewage
Each of the plants have two settling tanks that
separates the solid fecal matter and the watery
phase. The fecal matter is pumped to the
digestor feed pump station and then pumped to
anaerobic digestors or an acid generation tank
from a primary sludge pump station. The water
phase goes to a balancing tank in the case of
the new plant and directly to the anaerobic or
anoxic sones of the Badenpho. In the case of
the Polishing plant the overflow of the settling
tanks is pumped to two biological filters.
-
2-
DISCRIPTION
PURPOSE
Anaerobic digestors
The sludge is pumped from the various settling
tanks into the three digestors. In the digestors
the sludge is digested in the absence of oxygen
to form carbondioxide and methane. Methane
and carbondioxide are collected in a gas storage
tank. The digested solids is pumped into a
lagoon from a waste sludge pump station.
Acid generator
The acid generator is also fed from the settling
tanks. The fecal matter ferments and forms
acitates that are reintroduced with the sludge to
the balancing dam and fed to the other two
plants. Retention time in the acid generator is ±
six days.
Balancing dam
The balancing dam is used to balance the flow
of the two new reactors. Sewage is pumped at a
rate of ± 22 Mega liters per day by variable
speed motored pumps and divided equally
between the two reactors (11Mega liter each).
Sewage is constantly kept in a suspension by
banks of stirrers.
The new Reactors (22 Mega liter capacity each)
The new reactors are both extended aerations
plants with anaerobic, anoxic and aeration
sones. The plants configuration can be changed
to either function as a fhoredox or a UCT plant.
Badenpho Plant
The Badenpho plantt has been modifed to
become a three stage extended aeration plant
with an anoxic, anaerobic and an aeration sone.
Polishing Plant
After passing the settled sewage through a
biological filter the sewage enters an anoxic
sone followed by an aeration sone to help with
nutrient removal.
-
3-
DISCRIPTION
PURPOSE
Mixed liqour suspended solids pump stations
In the case of the new Reactors a variable
speed drive pump is used on each of the
reactors to pump mixed liquor suspended solids
from the end of the aerobic sone into the
anaerobic or anoxic sones.
In the Badenpho Plant and the Polishing Plant
lifter pumps is used for circulation.
In the Polishing plant two circulation pumps is
used.
Secondary Clarification
The mixed liqour flows into the secondary
carifiers. The sludge and the treated water are
seperated. The return activated sludge (the
underflow of the clarifiers) goes to pump stations
and the treated water to chlorination.
Return Activated Sludge Pump Stations
In the case of the new Plant and the Polishing
Plant the return activated sludge is pumped with
Gorman Rubb pumps from a sump and return to
various points in the reactors.
The Badenpho Plant uses two archimedes
screw pumps to pump the return activated
sludge.
Retention time
The retention time in the two new reactors are
regulated by waste activated pump stations with
timers set to the necessary pump schedules.
The waste activated sludge is pumped to a
waste activated sludge thickener. The overflow
goes to chlorination whilst the underflow is
pumped by a waste activated sludge pump to
the sludge lagoons.
In the case of the Badenpho and Polishing Plant
a continious draw off is used to regulate the
retention time. The wasted mixed liqour solids
goes to a sludge thickener. The underflow goes
to a waste activated sludge pump station and is
pumped to the sludge lagoons. Overflow goes to
chlorination.
-
4-
DISCRIPTION
PURPOSE
Chlorination
The total overflow of the secondary clarifiers and
the waste sludge thickeners goes to the
chlorination unit at the head of the chlorine
contact tank. The treated water leave the plant
to flow through three in series connected
maturation ponds before flowing through a read
bed into the Mooi River.
Final pump to lagoon
A pumpstation deliver treated water to the
sludge lagoon to maintain a clean water blanket
over the sludge.
Activated sludge recycle pump station
Transmits activated sludge from the Badenpho
reactor to the inlet to limit odour emissions from
the inlet works.
Second class water distribution pumps and Distributes treated effluent from a booster pump
system
into the chlorine contact tank to various units in
the proses for washing etc.
Stabilised sludge distribution pump
Transmits stabilised sludge from the sludge
lagoons to lands for irrigation of sludge.
Scum removal pumps
Decanted scum from the new primary settling
dams to the digestor feedpump station.
Methane gas incinerators
The methane gas collected from the anaerobic
digestors and in the collection vesel is piped to
the methane fired incinerator at the inlet works.
The incineration of rags and plastics take place
in the incinerator.
-
5-
Potchefstroom Waste Water Treatment Works general outlay
-
6-
FLOW DIAGRAM
-
7-
-
8-
Badenpho and Polishing Plant Layout
-
9-
2.
i.
PROPOSED TEAM TO CONDUCT THE WASTE WATER RISK ABATEMENT
PLAN
Engineer
JF Kleinhans -Department Infrastructure – Tlokwe City Council
ii.
Catchment Manager
L Caldwell – Department Water Affairs
JF Kleinhans - Department Infrastructure – Tlokwe City Council
iii.
Environmental: Public Health and Hygiene Professionals
JM van Niekerk
Municipality
BCK Nell
iv.
Environmental Health Services – Dr Kenneth Kaunda District
Water Quality Monitoring – Tlokwe City Council
Consumer representatives
S Thomas – Farmer’s representative.
T Kruger - Councilor
-
10 -
3.
ASSESSMENT OF THE CATCHMENT AND RISK EVALUATION
a. Description of the water resource north of Potchefstroom
The Mooi River with its two main tributaries, the Wonderfonteinspruit and the Loopspruit has a
relative flat topography with elevations varying from 1520m in the north to 1300m in the southwest.
The Mooi River originates in the Boons area. The Bowenste oog” in the Mathopestad area near
Ventersdorp contributes to the flow. The river passes through the Klerkskraal dam, the Boskop
dam and the Potchefstroom dam (Lakeside Dam) before flowing into the Vaal River
approximately 20km downstream from Potchefstroom. The Wonderfonteinspruit originates in the
southern part of Mogale City (Krugersdorp) at the Tudor dam and passes through the Lancaster
dam and the Donaldson dam. The origins of the Wonderfonteinspruit are on the southern side of
the Witwatersrand ridge. The catchment divides between the Vaal River system and the
Crocodile West/Marico catchments. The Wonderfonteinspruit then flows through the Municipal
areas of Westonaria and Merafong into the Mooi River at the Gerhard Minnebron area
approximately 10 km above the Boskop dam.
The Gatsrand, a steep sided rocky ridge is the catchment divide between the Loopspruit and
Wonderfonteinspruit. The Gatsrand area is one of the rich goldfields of South Africa and both the
Loopspruit and Wonderfonteinspruit runs through mining areas.
One of the larger dams in the Loopspruit is the Klipdrift dam and many irrigation farmers depend
on the water from this dam. The Loopspruit flows into the Mooi River on the southern side of
Potchefstroom ± 500m upstream of the Tlokwe Sewage Works.
Various eyes feed into the Wonderfonteinspruit and the Mooi River between Merafong City and
Potchefstroom. These eyes are overflows from the Turfontein compartment and the Boskop
compartment. The Turfontein eyes, Gerhard Minnebron and Katdoringbos eyes are some of the
larger eyes. The Oberholzer, Vensterspost and Bank dolomitic compartments have been
dewatered. An one (1) meter pipeline from Donaldson dam to the Boskop – Turfontein
compartment crosses these compartments.
Due to the contamination of groundwater that infiltrates the mine workings, various heavy metals
and uranium are found in underground water discharges that reach the Wonderfonteinspruit. To
a lesser extend this also happens in the Loopspruit catchment.
-
11 -
-
12 -
b)
Anthropogenic impacts on the water resources north of Potchefstroom.
In the upper part of the catchment gold mining has taken place over a period of more than 100
years. In the 1950’s the lower part of the catchment became the focus of mining activities. For a
while pyrite and uranium were removed as byproducts to gold.
Water courses and dolomitic compartments became polluted due to the placement of mining
tailings dams and slimes dams. These facilities are often in a state of poor management and are
often the main culprits in the pollution process.
Various waste water treatment works discharge into the Wonderfonteinspruit namely Flip Human
(Westonaria) and three smaller waste water treatment works at Merafong City. The Loopspruit
receive waste water from Khokosi at Fochville and other smaller works.
Uranium, sulphates and other heavy metals are some of the waste load that the mines have on the
surface and underground water resources. The wastewater works’ major contributions are
phosphates, nitrates and sometimes high chemical oxygen demands due to the discharge of
sewage sludge and untreated sewage.
The farming activities that take place on the Mooi River proper may contribute to the nitrogen and
phosphate loads in the river. Both farming practices and waste water works contribute to high fecal
bacterial pollution.
-
13 -
c)
Catchment area from the Potchefstroom dam (Lakeside dam) to the Vaal River.
The Mooi River flows through Potchefstroom. The City was built on both sides of the river. The
Wasgoedspruit enters the Mooi River ±3km from Potchefstroom dam. The Wasgoedspruit flows
through informal settlements and the industrial area. Small dolomitic eyes below the old Kynoch
gypsum dam flows into the spruit. The Poortjie dam to the west of the gypsum dam lies between
Promosa and Ikageng. The water of Poortjie dam is often polluted by sewage due to blocked pump
stations. In the industrial area illegal discharges may find their way into the spruit. It is possible that
these pollutants can find their way to the Mooi River.
The southerly tip of the Boskop compartment underlies the gypsum dam and is polluted with
sulphates and phosphates. This pollution dam moves in an eastern direction and boreholes in this
area will be more and more polluted until after the removal of the gypsum dam the water starts to
clean up.
Lower down the river the Botha Street pump station and the Eland street pump station can overflow
into the Mooi River. The Loopspruit with its own salt load confluence with the Mooi River ± 500m
above the sewage works. Maturation ponds are built next to the river and the extensive wetlands
below these ponds must be maintained with water from the ponds. After ± 1km of reed beds the
sewage final effluent from Tlokwe enters the river. The downstream farmers use water for irrigation.
The only segment tributary lower down the river is the Rooikraalspruit that also flow through
agricultural areas. The Mooi River enters the Vaal River at Kromdraai. This point is ± 15km from the
Midvaal Water Treatment Works.
-
14 -
d.
HAZARD ASSESSMENT MATRIX
LIKELIHOOD
Almost certain
(once a day or permanent feature)
RATING
1
Likely
(once per week)
0.8
Moderately likely
(once per month)
Unlikely
(once per year)
Rare
(1 in 5 years)
0.5
0.2
0.1
CONSEQUENCE
Catastrophic
(Death expected from exposure)
Major
(Population exposed to significant
illness)
Moderate
(Large aesthetic impact)
Minor
(Small aesthetic impact)
Insignificant
(No impact)
RATING
100
70
20
2
1
RISK RATING = LIKELIHOOD X CONSEQUENCE
Risk Profile:
Low (L) – 0-10
Medium (M) – 11-56
High (H) – 57-100
-
15 -
e)
Risk evaluation of the Catchment
NAME OF CATCHMENT:
Mooi River Catchment
LOCATION OF CATCHMENT:
North West and Gauteng Province
CATCHMENT CONSISTS OF:
Dams
PERSON IN CHARGE OF CATCHMENT:
Department of Water Affairs (DWA)
POSTAL ADDRESS:
POSTAL CODE:
Private Bag x936
Potchefstroom
2520
TELEPHONE NUMBER:
27(0)18 2949300
FAX NUMBER:
27(0)18 2948233
E-MAIL:
[email protected]
GPS
26’ 43’ 34 S 27’ 4’ 28’ E
Is the Catchment
vulnerable to
contamination from
the following
Upstream
industries
and mines
x
Recreational
use by
community
x
Agricultural/
Livestock
farms
x
Rivers
Dolomitic eyes
Sewer
Systems/
Pump station
overflow etc.
x
Surface fecal
run off
x
Abandoned
mines
x
Indicate which protection plans Permits for Mines and
exists
Sewage works
x
Rehabilitation Plans –
Wonderfonteinspruit
(WFS)
x
-
16 -
Upper Wonderfontein (WFS) Catchment Assessment
List existing
Name Control
risks that could measures /if any
impact on the
Catchment
Is the
Control
measure
effective
Y/N
Likeli
hood
of
occur
rence
Consequence
of occurrence
Risk
Rating
Risk
Priority
L – Low
M–
Medium
H - High
Pollution of
WFS from
derelict mines
and tailings
facilities
Rehabilitation of
identified sites
(not started yet)
Y
1
60
60
H
Pollution of
WFS by mines
in production
1.Use permit
system to
regulate mine
discharges
Y
0,5
80
40
M
Y
0,7
60
42
M
Y
0,4
20
8
L
2.Regular
monitoring of
Catchment
3.Meetings with
pollen mines
4.Alerting DWA of
problem
Spillage of raw
sewage into
Wonderfontein
Spruit
1. Regular
monitoring.
Spillage from
Road tankers
washed into
river by rainfall
Emergency
Services
(Hazmat)
following Cleanup
protocol
2. Alert DWA of
the problem
-
17 -
List existing
Name Control
risks that could measures /if any
impact on the
Catchment
Is the
Control
measure
effective
Y/N
Likeli
hood
of
occur
rence
Consequence
of occurrence
Risk
Rating
Risk
Priority
L – Low
M–
Medium
H - High
Agricultural
chemical or
fertilizer landing
in river
Use Forums to
educate farmers
in the use of
chemicals
Y
0,3
30
9
L
Animal waste
wash into the
River
Discuss siting of
feedlots and
milking paroles.
Use DWA officials
if necessary
Y
0,2
50
10
L
-
18 -
Potchefstroom Dam to the Vaal River Catchment Assessment
List existing
Name Control
risks that could measures /if any
impact on the
Catchment
Is the
Control
measure
effective
Y/N
Likeli
hood
of
occur
rence
Consequence
of occurrence
Risk
Rating
Risk
Priority
L – Low
M–
Medium
H - High
Pollution of Mooi
River due to
high fecal
pollution of the
Wasgoedspruit
as well as
Industrial
pollution of the
spruit.
1.Monitor Mooi
River below
confluence with
Wasgoedspruit
(point 9)
2. Monitor
sewage pump
station in western
townships daily.
3. Provide
serviced plots for
building.
4. Constrain
illegal building.
5. Monitor
Industrial area.
Y
0,5
50
30
M
Raw sewage
pollution due to
failures at Botha
Street pump
station.
1. Alarm system
to alert
superintendent
via cell phone.
2. Power
generator
available in case
of electrical
failure.
3. Spare pump
available at the
pump station.
4. Monitoring of
Mooi River below
Botha Street
pump station
(point 10)
Y
0,6
80
48
M
-
19 -
List existing
Name Control
risks that could measures /if any
impact on the
Catchment
Is the
Control
measure
effective
Y/N
Likeli
hood
of
occur
rence
Consequence
of occurrence
Risk
Rating
Risk
Priority
L – Low
M–
Medium
H - High
Pollution due to
storm water
transporting
plastic and fecal
matter into Mooi
River
1. Street
Cleaning.
2. Provision of
adequate
sanitation.
3. Inspection of
sewage pump
station to prevent
raw sewage
wastage into
storm water
system
Y
0,4
70
28
M
Pollution of Mooi
River by the
Loopspruit with
mining and fecal
pollutants
1. Monitor the
Mooi River below
the confluence
with the
Loopspruit (point
10).
2. Alerting DWA
to problems.
Y
0,3
70
21
M
Pollution of the
Mooi River by
the Tlokwe
Waste Water
Treatment
Works with poor
quality final
effluent and
sewage sludge.
1. Monitor River
below sewage
works (point 11).
2. Monitor
WWTW final
daily.
3. Maturation
ponds and reed
bed severe as
abatement in
case of spillage.
Y
0,3
30
9
L
-
20 -
List existing
Name Control
risks that could measures /if any
impact on the
Catchment
Pollution of river
below sewage
works by
agricultural
pollution with
fecal matter
from feedlots
and phosphate
and nitrate
fertiliser from
fertiliser misuse.
1. Monitor river at
point 12.
2. If a problem
occur contact
DWA officials
Is the
Control
measure
effective
Y/N
Y
Likeli
hood
of
occur
rence
0,2
Consequence
of occurrence
20
Risk
Rating
Risk
Priority
L – Low
M–
Medium
H - High
4
L
-
21 -
4. ASSESSMENT OF WASTE WATER TREATMENT WORKS AND RISK EVALUATION
a)Details of Waste Water Treatment Plant
NAME OF WASTE WATER TREATMENT
WORKS
Tlokwe Waste Water Treatment Works
LOCATION OF TREATMENT WORKS:
Potchefstroom North West Province
RECYCLING CATCHMENT:
Mooi River Catchment
PERSON IN CHARGE OF WASTE WATER
TREATMENT WORKS
Engineer: JF Kleinhans
Superintendent: C de Jager
Chief Chemist: BCK Nell
STREET ADRESS
Viljoen Street
Potchefstroom
POSTAL ADRESS
PO Box 113
Potchefstroom
2520
CONTACT DETAILS
JF Kleinhans: Office: +27(0)18 2995404
Cell: 0833624935
C de Jager: Office: +27(0)18 2947137
Cell: 0836457074
BCK Nell: Office: +27(0)18 2947744
Cell: 0729076801
FAX NUMBER:
+27(0)18 2948203
E-MAIL:
[email protected]
[email protected]
[email protected]
GPS
LAT. -26.75952 LON: 2709517
-
22 -
b) HAZARD ASSESMENT MATRIX
LIKELIHOOD
Almost certain
(once a day or permanent feature)
RATING
1
Likely
(once per week)
0.8
Moderately likely
(once per month)
Unlikely
(once per year)
Rare
(1 in 5 years)
0.5
0.2
0.1
CONSEQUENCE
Catastrophic
(Death expected from exposure)
Major
(Population exposed to significant
illness)
Moderate
(Large aesthetic impact)
Minor
(Small aesthetic impact)
Insignificant
(No impact)
RATING
100
70
20
2
1
RISK RATING = LIKELIHOOD X CONSEQUENCE
Risk Profile:
Low (L) – 0-10
Medium (M) – 11-56
High (H) – 57-100
-
23 -
c.)
ASSESMENT OF THE WASTE WATER TREATMENT WORKS AND RISK
ABATEMENT PLAN
Hazard
Name control
measures if any
Is
control
measures
effecttive Y/N
1
Power Failure:
Raw sewage will
flow
into
maturation
ponds
Install a power
generator to supply
electricity to the
WWTW
Y
2
Broken
mechanical
screen at inlet.
(Mechanical
Screen failure):
Hand raking of
screens then
necessary.
Install a spare
mechanical screen
to be able to
service one screen
while the other one
is working.
3
Odour problem
at inlet:
Odours
will
affect
nearby
community.
4
Mechanical
failure of pumps
in
Vortex
degritters:
Degritters will fill
up
with
grit
which will have
to be removed
by hand. Grit will
enter into the
rest
of
the
process.
Likelihood
that
hazard
may
occur
Consequ
ence if
hazard
occur
Risk
Rating
Risk
priority
0,5
50
25
M
Y
0,2
20
4
L
Pump MLSS from
the Badenpho with
the
activated
sludge recycle to
inlet
Inlet
totally
covered.
Y
0,5
20
10
L
Isolate the degritter
with broken pump
and use only one
degritter. Pull the
pump out of vortex
degritter, replace
with spare pump
and
have
the
broken
pump
repaired
follow
operational
manual.
Y
0,2
20
4
L
-
24 -
Hazard
Name control
measures if any
Is
control
measures
effecttive Y/N
5
Electrical
or
mechanical
failure
of
distribution pump
station:
All the sewage
that enters will
go to the New
Plant with the
consequential
flooding of the
plant.
If electrical failures
occur
get
the
correct electrician
to attend to the
problem.
If
mechanical
problems
occur
isolate the broken
pump.
Remove
and
send
for
repairs. Use spare
pump in the pump
station.
Y
6
Blockage
of
primary settling
tanks:
Sludge buildup
in the tank with
poor settling and
the
possible
damage
to
scrapers.
Get the team from
sewer maintenance
to
open
the
blocked pipe. Use
different
configurations
of
plants to lessen
flow to the blocked
primary
settling
tank and seal flow
off
while
the
problem is rectified.
Y
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
0,2
70
14
M
0,2
70
14
M
-
25 -
Hazard
Name control
measures if any
7
Mechanical
or
electrical failure
of bridges at the
primary settling
tanks: Buildup of
sludge in the
primary settling
tanks. Eventual
rotting of sewage
can
cause
filamentous
bacteria.
As above. Change
configurations
to
have more water to
the
two
other
plants. Seal off the
primary
settling
dam. Rectify the
problem.
If
necessary
bring
mobile pumps in
and empty PST.
Rectify
problem
and return to usual
configuration.
8
Failure
(Mechanical or
electrical) of the
pumps in the
primary settled
sludge
pump
station:
Building up of
sludge in the
primary settling
tanks.
Sludge
sumps
may
overflow.
May
lead to food
shortage
in
reactors
stimulating
filamentous
bacteria
development.
If
mechanical
problem, use the
spare
pump
available in the
pump
station.
Remove and repair
the default pump. If
electrical problem
occur other than
the
motor
get
electricians
to
rectify problem.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,2
50
10
L
Y
0,2
70
14
M
-
26 -
Hazard
Name control
measures if any
9
Blockage in the
fermentation
tank: Less food
for bacteria may
lead to bulking
due
to
filamentous
bacteria.
Overloading of
digesters, drop
in pH and less
Methane.
All
sludge
to
anaerobic
digesters.
Get
mechanical
maintenance team
to
do
the
necessary repairs.
If necessary drain
the
acid
fermentation tank
into the Balancing
tank and unblock if
possible and repair
where necessary.
10
Electrical
or
mechanical
failure of stirrers
in the balancing
dam;
Buildup
of
sludge in the
Balancing dam –
low food/mass
ration
to
reactors. Bulking
of mixed liquor
solids
in
secondary
clarifier. Difficulty
in re-suspension
of sludge
If not the motor, the
plant
electrician
must rectify the
electrical problem.
If the problem is
mechanical or the
motor
is
the
problem
the
mechanical
maintenance team
have to remove the
gearbox and motor.
Send for repairs if it
cannot be done
locally.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,2
50
10
L
Y
0,5
20
10
L
-
27 -
Hazard
Name control
measures if any
11
Toxic sewage to
reactors:
Proses
failure
due to the loss of
bacteria. Rotting
sewage
to
maturation
ponds.
If a flow of toxic
sewage
is
suspected switch
off the distribution
pumps to save at
least two of the
three reactors.
Monitor incoming
raw sewage and
monitor industries
discharges
regularly.
12
Mechanical
or
electrical failure
of transfer pump
station in the
new Plant:
Only
the
Badenpho and
Polishing Plant
will be running.
Both
will
be
overloaded. The
consequence is
a poor quality
effluent.
Determine whether
the problem is
electrical and get
the plant electrician
to
rectify
the
problem. If a pump
motor or other
mechanical
problem
occurs,
close
the
necessary
valve
and remove for
repairs. Open the
spare pump set’s
valves and use
spare pump. If all
the pumps are out
of commission use
Gorman pumps on
trailer to pump to
the next stage.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,1
100
10
L
Y
0,2
70
14
M
-
28 -
Hazard
Name control
measures if any
13
Mechanical
or
electrical failure
of stirrers in the
anoxic
and
anaerobic zones.
Buildup
of
sludge in the
anoxic
or
anaerobic zones.
This will lead to
process failure
and poor effluent
quality.
Usually more than
one
stirrer.
Remove the stirrer
if the motor or
gearbox
is
dysfunctional. If it
is only an electrical
problem have the
plant electrician to
rectify the problem.
14
Aerator failures
due to electrical
or
mechanical
problems:
Lead to under
aeration
of
MLSS,
high
ammonia
and
chemical oxygen
demand
and
poor
quality
effluent.
Determine
problem. If the
plant
electrician
can rectify the
problem get the
electrician
otherwise remove
the
motor
or
gearbox
if
necessary
and
send for immediate
repairs.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,2
50
10
L
Y
0,5
20
10
L
-
29 -
Hazard
Name control
measures if any
15
Blockage
of
secondary
clarifier:
Lead
to
overflowing
of
suspended
solids in the
effluent.
Poor
quality effluent
and
process
failure.
Isolate the blocked
clarifier and get the
mechanical
maintenance team
to unblock pipe so
that sludge flows
freely.
16
Clarifier
stoppages due
to mechanical or
electrical failure:
Lead
to
overflowing
of
suspended
solids in the
effluent.
Poor
quality effluent
and
process
failure.
Isolate
dysfunctional
clarifier and
reconfigure flow to
plants. If the
problem lies with
the gearbox or
clarifier wheel
remove and repair.
If the problem lies
with the motor –
remove and have
rewired, If the
stirrers on the floor
is dysfunctional get
a mobile pump and
empty – repair and
put back into
operation.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,2
70
14
M
Y
0,1
70
7
L
-
30 -
Hazard
Name control
measures if any
17
Mechanical and
electrical failure
of
return
activated sludge
pumps:
Sludge buildup
in the secondary
clarifiers
and
overflow
into
final
effluent.
Loss of bacteria.
Process failure.
Poor quality of
effluent with high
amount
of
suspended
solids.
If the problem is
electrical call the
plant electrician to
rectify immediately.
If the electrical
motor or the pump
is faulty remove
and
repair
immediately. Use
spare pump in the
pump station.
18
Mixed
liquor
return
pumps
mechanical
or
electrical failure.
Nitrogen removal
will be affected high amounts of
Nitrate as well as
phosphates
in
final effluent.
If the problem is
electrical call in the
plant electrician to
rectify the problem.
If the motor or
pump
is
malfunctioning,
remove and repair.
Use mobile pump
to
do
the
necessary pumping
until the pump is
reinstalled and in
working order.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,2
100
20
M
Y
0,5
20
10
L
-
31 -
Hazard
Name control
measures if any
19
Chlorination unit
out of order.
Final
effluent
with high E.coli
and
Total
Coliform count.
Final
effluents
quality failure.
Repair the unit
immediately. Use
HTH
dosing
system while the
chlorine gas unit is
being repaired.
Maturation ponds
designed to make
use of ultra violet
radiation from the
sun to disinfect
effluent
20
Gas leakage at
the digesters.
Can cause loss
of
life
and
destruction
of
facility.
Put
up
“No
Smoking” signs on
all digesters. Train
personnel to not
use open flames
near the digesters.
Inspect
flame
arrestors on gas
line regularly. If
leaks occur get the
fire brigade in and
supply
the
necessary
information.
Cordon
the
surrounding area
off and only allow
safety personnel to
enter. Rectify the
problem as soon
as possible.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,2
70
14
M
Y
0,2
100
20
M
-
32 -
Hazard
Name control
measures if any
21
Overloading of
digesters.
Low pH, poor
quality gas. Not
able to sustain
incinerator.
Test the pH of the
digester sludge at
regular intervals. If
overloading occur
direct sludge to
acid
generation
until the pH return
to normal.
22
Cable theft.
Lead to electrical
failure
of
equipment
or
plant.
23
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,5
20
10
L
Deploy 24 hour
security on the
premises and the
plant. Cover cables
to keep out of
sight.
Y
0,2
100
20
M
Lack of regular Use maintenance
maintenance of manual to do daily,
gearboxes etc.
weekly, bi-weekly
and
monthly
Lead
to maintenance.
mechanical
Execute
failure
of inspections
to
equipment with make
sure
process failures maintenance
is
as a result. Poor done regularly. Put
quality effluent
other
control
measures in place
e.g.
job
cards
etc.to
monitor
maintenance.
Y
0,3
70
21
M
-
33 -
Hazard
Name control
measures if any
24
Failure to waste
sludge
from
process.
Lead to high
MLSS. This will
lead to high
ammonia
and
high phosphates
in
the
final
effluent.
High
suspended
solids will also
occur with high
chemical oxygen
demand in final
effluent.
Poor
quality effluent.
Regular checking
and inspection of
MLSS
in
the
reactors
will
indicate
whether
sludge is wasted. If
MLSS is rising the
retention time is
too
long
and
sludge
is
not
waste.
Address
plant
superintendent to
rectify the problem.
25
Unattended
sludge wasting
on land.
May lead to
sludge
flowing
into the Mooi
River.
26
Dumping of rags
and plastics as
well as grit.
If not covered
with soil it may
lead to smells
and fly breeding.
Is
control
measures
effecttive Y/N
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
Y
0,4
70
28
M
When
pumping
sludge make sure
personnel is on
site. Don’t pump
sludge
over
weekends and at
night. Never pump
sludge
without
supervision.
Y
0,2
70
14
M
Inspect site where
grit and plastics are
buried. If flies are
encountered use
scatter poison to
make sure flybreeding does not
take place.
Y
0,8
50
40
M
-
34 -
Hazard
Name control
measures if any
27
Get the necessary
storm
water
reticulation
in
place. Make sure
all manhole covers
are
in
place.
Building inspectors
to
make
sure
gullies at building
sites and houses
are in place.
High
rainfall
incidents
with
associated
infiltration
of
rainwater.
Flooding of the
inlet
works.
Untreated
sewage
to
maturation
ponds. Grit sand
and stones may
harm mechanical
screens. Wash
out of bacteria in
the reactors may
lead to process
failures.
Is
control
measures
effecttive Y/N
Y
Likelihood
that
hazard
may
occur
Consequence if
hazard
occur
Risk
Rating
Risk
priority
0,5
70
35
M
-
35 -
NOTE
All quality failures will eventually lead to poor quality final effluent reaching the Mooi River with the
possibility of eutrophication of the river. It may also pose a threat to animals and crop irrigation
downstream.
-
36 -
5. ASSESSMENT OF THE WASTE WATER SEWER RETICULATION SYSTEM AND RISK
EVALUATION
a) Details of Sewer Reticulation System
Each household stand in Potchefstroom has a waterborne sewer connection onto the Municipal
sewer reticulation system which total up to approximately 43 500 stands.
There are several main sewers:
1. Two from Ikageng straight to the WWTW via Potchindustria and Agricultural College.
2. One from the central and southern areas of Potchefstroom to the WWTW.
3. Then there are three main sewers which serve all the areas east of the Mooi River, the
Promosa/Mohadin main sewer serving part of Ikageng and Potchindustria and also serving
Dassierand. Bult (which include the University), Military base and the CBD all going to the
Botha Street pump station and from there to the WWTW.
Due to the fact that Potchefstroom is very flat there are 27 pump stations which are part of the
reticulation system. There are two high capacity pump stations complete with standby generators of
-
37 -
which the Promosa pump station serves parts of Promosa and Ikageng. The second one is known
as the Botha Street pump station and serves approximately 75% of the total runoff of
Potchefstroom. Both pump stations are manned during the day while the Promosa pump station is
manned at nights by a security guard. All the other pump stations are serviced on a daily base by
two maintenance teams.
-
38 -
b) HAZARD ASSESMENT MATRIX
LIKELIHOOD
Almost certain
(once a day or permanent feature)
RATING
1
Likely
(once per week)
0.8
Moderately likely
(once per month)
Unlikely
(once per year)
Rare
(1 in 5 years)
0.5
0.2
0.1
CONSEQUENCE
Catastrophic
(Death expected from exposure)
Major
(Population exposed to significant
illness)
Moderate
(Large aesthetic impact)
Minor
(Small aesthetic impact)
Insignificant
(No impact)
RATING
100
70
20
2
1
RISK RATING = LIKELIHOOD X CONSEQUENCE
Risk Profile:
Low (L) – 0-10
Medium (M) – 11-56
High (H) – 57-100
-
39 -
c.
RISK EVALUATION OF THE WASTE WATER RETICULATION SYSTEM
AREA COVER BY SEWER SYSTEM:
Greater Potchefstroom Area
SEWER SYSTEM CONSIST OF:
Pump stations, Main Sewer lines, smaller sewer
lines
PERSON IN CHARGE OF SEWER SYSTEM
Engineer: JF Kleinhans
Department Infrastructure Tlokwe City Council
SUPERINTENDENT IN CHARGE OF
SEWER SYSTEM:
Lance Carson
Department Infrastructure
Tlowke City Council
POSTAL ADRESS
PO Box 113
Potchefstroom
2520
CONTACT DETAILS
JF Kleinhans: Office: +27(0)18 2995494
Cell: 0833624935
Lance Carson: Office: +27(0)18 2995433
Cell: 0837430918
FAX NUMBER:
+27(0)18 2948203
E-MAIL:
[email protected]
[email protected]
-
40 -
d.)
ASSESMENT OF THE SEWER RETICULATION SYSTEM AND RISK
ABATEMENT PLAN
Hazard
Name control
measures if any
Is
control
measures
effecttive Y/N
1
Electrical failure:
Pump
stations
not operational,
raw
sewage
overflow in storm
water system
1. Main pump
station supplied
with backup power
generator.
2. Smaller pump
stations: disinfect
with lime of
chlorine.
3. Wash away raw
sewage that cannot
be picked up.
Y
2
Pump
dysfunctional
due to
mechanical or
electrical faults:
Pump station will
overflow into
storm water
system
1. Supply two
pumps per station.
Pumps to run
alternatively.
2. Turn selector
switch in electrical
panel so that one
pump runs
continuously.
3. Install spare
pump while
dysfunctional pump
is been repaired.
Y
Likelihood
that
hazard
may
occur
Consequ
ence if
hazard
occur
Risk
Rating
Risk
priority
0,6
80
48
M
0,5
20
10
L
-
41 -
Hazard
Name control
measures if any
Is
control
measures
effecttive Y/N
3
Theft of manhole
covers
on
sewage lines:
The open shafts
pose
a
dangerous
situation.
Storm water can
flow into sewer
system.
Alien objects can
be thrown into
sewer that may
block the sewer
lines.
1 .Replace
manhole covers
with heavy cement
blocks that are
worthless when
stolen.
2.
Regular
inspection of sewer
lines to see to it
that manholes are
covered.
Y
4
Sewer line
blockages due
to:
*Natural causes
*Stones and
objects
introduced into
system.
Raw sewage will
back up in the
lines and start to
overflow
in
houses.
1. If sewage line is
blocked due to
sewage building up
– get sewage
rehabilitation team
to open lines with
rods.
2. If stones have
been thrown into
lines get pump
sand hoses to
reroute sewage
and open lines with
machines.
Removed blocked
section.
3. Seal manholes
with heavy cement
blocks where
possible.
Y
Likelihood
that
hazard
may
occur
Consequ
ence if
hazard
occur
Risk
Rating
Risk
priority
0,8
80
64
H
0,5
60
30
M
-
42 -
Hazard
Name control
measures if any
Is
control
measures
effecttive Y/N
5
Sewer
line
collapse due to
corrosion: The
line
will
be
blocked and if
the line runs
under a street
will cause road
to collapse. Raw
sewage
will
enter
storm
water system.
1. Inspect older
lines with cameras.
If corroded – line
the pipes with
trenchless
technology.
2. If line collapse –
reroute sewage by
using portable
pumps.
3. Excavate area
immediately and
reline pipes.
Inspect rest of the
pipe.
Y
6.
Storm
water
ingress in sewer
lines: Flooding of
sewage works,
overflowing from
lines
and
wasting
of
sewage
in
streets etc.
1. Keep storm
water system clean
and operational.
2. Make sure
manhole covers is
in place.
3. Building
inspectors to make
sure gullies are in
place.
7
Blockage due to
fat built ups from
restaurants,
abattoirs
etc.
Capacity of line
will be seriously
affected
and
compromised.
1. Building
inspectors to make
sure fat traps are
well constructed.
2. If dumping of fat
takes place enforce
by-laws and use
by-laws to force
polluter to pay cost
of line
rehabilitation.
Likelihood
that
hazard
may
occur
Consequ
ence if
hazard
occur
Risk
Rating
Risk
priority
0,3
70
21
M
Y
0,4
60
24
M
Y
0,3
60
18
M
-
43 -
6. SEWER COMPLAINTS AND QUALITY CONTROL PROTOCOL
-
44 -
7. MANAGEMENT PROCEDURES
A.
FINAL EFFLUENT QUALITY FAILURE MANAGEMENT PLAN
MICROBIOLOGICAL FAILURE
1.
2.
Alert the Manager Water and Sewerage that a failure has occurred.
As the results of the bacterial testing is only available after 20 hours it is not necessary to
take a validation sample because the daily sample will be in the process of being tested.
However the following steps must be taken:
a) Inform the Manager Water and Sewerage of the failure
Contact person: JF Kleinhans - Tel: 018 – 2995404 or cell: 083 362 4935
Plant Superintendent C de Jager - Tel: 018 – 2947137 or Cell: 083 645 7074
b) The Superintendent of the Waste Water Purification plant must adjust chlorine dosing to
the current hydraulic flow pattern and increase the testing rate of the free chlorine to
once per hour.
c) Do additional bacterial tests after 6 hours to make sure steps taken is effective
d) Log failure on the green drop system
e) If failure persist start dosing granular chlorine till problem is solved
CHEMICAL FAILURE
Chemical Oxygen Demand Failure
1.
If a Chemical Oxygen Demand failure occurs validation tests must be done.
2.
Alert Manager Water and Sewage that a failure occurred.
3.
If the validation sample is positive the following steps must be taken:
a) Inform the Manager Water and Sewage that a failure in the chemical oxygen demand
occurred.
Contact person: JF Kleinhans – Tel: 018 – 2995404 or Cell: 083 362 4935
Contact Plant Superintendent – Tel: 018 – 2947137 or Cell: 083 645 7074
-
45 -
b) Determine if a mechanical failure of aerators occurred. This is usually the reason for
COD failure if not sample the inlet raw sewage and determines if excessively high COD
is reaching the plant. If this is the case determine where the origin of the high COD
effluent is. Take action to stop this practice immediately.
c) 1. If phosphate level failure occur a validation test must be done.
2. Alert Manager Water and Sewage that a failure occurred.
3. If the validation test is positive inform Manager of Water and Sewage.
Contact person: JF Kleinhans – Tel: 018 – 2995404 or Cell: 083 362 4935
Superintendent WWTC C de Jager–Tel: 018 – 2947137 or Cell: 083 645 7074
4. Put mitigation steps in place according to operation manual.
5. Log failure on the Green Drop system.
6. If mitigation steps are not effective, start dosing ferrichloride.
d) Any other chemical failures follow the same procedure there is however nothing that can
be dosed for nitrates and ammonia
-
46 -
B.
ALERT LEVEL, ACTIONS AND RESPONSE
CHEMICAL AND MICROBIOLOGICAL ALERT LEVELS
Any chemical, physical or microbiological measure that falls outside the general standards or
values indicated on permit is seen as a failure and is an alert situation.
a) Actions
When the transgression of an alert level takes place immediate reaction is required
1.
The Chief Chemist must immediately when such result become known do the following:
Contact the Manager Sewage Treatment (JF Kleinhans: 018 – 2995404 or 083 362
4935)
Point the nature of the failure out and suggest possible mitigating steps to be taken
Visit the Waste Water Treatment Plant and help with mitigating steps
Resample and analyze the sample until the problem is solved
2.
The Manager Water and Sewage Treatment on receiving information on any Waste Water
Treatment failures must do the following:
Contact the Plant Superintendent of the Waste Water Treatment Plant and alert him to
the problem
Discuss and instruct the Plant Superintendent on mitigating measures
Visit Plant to make sure mitigation measures are implemented
Contact the Department of Water Affairs and report the failure
b) Response Time
The Chief Chemist:
As soon as all failures become known the alert has to go out. If the mitigating measure has to be
evaluated the necessary samples must be collected and the necessary determinations done on the
same day. Retesting must be carried out immediately.
The Manager Water and Waste Water Treatment:
Actions need to be taken the same day as information on failure becomes available. The
Department of Water Affairs must be contacted within 24 hours.
The Plant Superintendent:
Implementation of suggested rectifying steps must be taken once the information is received
without delays.
-
47 -
c) Contact Person and phone numbers
Manager: Water and Waste Water Treatment: JF Kleinhans - 018 – 2995404 or Cell: 083 362
4935
If not available
Superintendent reticulation system:
L Carson – 018 – 2995433 or Cell: 083 743 0918
Or
Chief Chemist: Ben Nell – 018 – 2947744 or Cell: 072 907 6801
Superintendent: Water Waste: Chris de Jager – 018 – 2947137 or Cell: 083 645 7074
-
48 -
8.
TLOKWE CITY COUNCIL WASTE WATER TREATMENT WORKS: WATER QUALITY
MONITORING PROGRAM
INTRODUCTION
The monitoring program is designed to satisfy the Department of Water Affairs and Forestry
requirements.
SECTION A: COMPLIANCE MONITORING
1.
FINAL EFFLUENT: DAILY MONITORING
1.1
1.3
Monitoring for flow and quality will be done at the point where the Final Effluent leaves the
chlorine contact canal.
A Grab sample of the Final Effluent must be taken at 08:00 every day and delivered to the
Laboratory before 08:30.
The following variables shall be measured on a daily basis:
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
pH
Suspended solids (mg/l)
Electrical Conductivity (MS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia (mg/l) as NH4
Nitrates (mg/l) as NO3
Phosphates (mg/l) as P
Sulphates (mg/l) as SO4
Chemical Oxygen Demand (mg/l)
Free Chlorine (mg/l)
Total Coliforms (counts/100ml)
E. coli (counts/100ml)
1.2
Amount of Samples
Amount of Analyses
DAILY
1
13
PER ANNUM
365
4745
-
49 -
2.
FINAL EFFLUENT WEEKLY MONITORING
2.1.
Once a week the following additional analysis shall be carried out on the final effluent.
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
Chlorides
Fluorides mg/l
Aluminium (mg/l)
Calcium ((mg/l)
Chromium (mg/l)
Copper (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Sodium (mg/l)
Hardness (mg/l)
2.2.
Number of samples and analyses.
Amount of Samples
Amount of Analyses
PER WEEK
1
11
PER ANNUM
52
572
3.
FINAL EFFLUENT BI-WEEKLY MONITORING
3.1.
Every second week a sample of the final effluent shall be analysed for the following
variables.
a)
b)
c)
d)
e)
f)
g)
Arsenic
Cadmium
Lead
Mercury
Nickel
Uranium
Antimony
3.2.
Number of samples and analyses:
Amount of Samples
Amount of Analyses
PER TWO WEEKS
1
6
PER ANNUM
28
168
-
50 -
4.
WEEKLY RIVER SAMPLES
4.1.
The quality of the river water shall be monitored by taking a grab sample at the following
monitoring points:
a)
b)
c)
Mooi River upstream from the point of final discharge of the sewage works at the bridge on
the Potchefstroom – Viljoenskroon road, marked 10 on the Map.
Mooi River just downstream of the point of discharge marked 11 on the Map.
Mooi River at Kromdraai mark 12 on the Map.
4.2.
The date, time and monitoring point in respect of each sample shall be recorded.
4.3.
Each sample shall be analysed for the following variables.
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
o)
p)
q)
r)
s)
t)
u)
v)
pH
Conductivity (mS/m)
Suspended Solids (mg/l)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia (mg/l) as NH4
Chlorides (mg/l)
Fluorides (mg/l)
Nitrates (mg/l) as NO3
Phosphates (mg/l) as P
Sulphates (mg/l) as SO4
Aluminium (mg/l)
Calcium (mg/l)
Chromium (mg/l)
Copper (mg/l)
Hardness (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Sodium (mg/l)
Total Coliforms (counts/100 ml)
E.coli (counts/100ml)
-
51 -
5.
TOTAL AMOUNT OF SAMPLES AND ANALYSES FOR COMPLIANCE
5.1.
Total amount of samples per annum
a)
b)
Waste Water Treatment Plant Effluent
River Samples
Total
5.2.
Total amount of analyses per annum
a)
b)
Waste Water Treatment Plant Effluence
River samples
Total
6.
:
:
365
156
521
:
:
5485
2332
7817
APPROVED METHODS TO BE USED
Analyses to be performed according to SABS methods / South African National Standards 241 of
2011 or methods accredited by the Department of Water Affairs and Forestry.
-
52 -
SECTION B: OPERATIONAL SAMPLES
Laboratory analyses to enhance plant operations
1.
DAILY ANALYSES
1.1
Incoming Raw sewage
Determinants:
a)
pH
b)
Electrical Conductivity
c)
Suspended Solids
d)
Ammonia as NH4
e)
Nitrate as NO3
f)
Phosphates as P
g)
Chemical Oxygen Demand
h)
Total Kelhdal nitrogen
1.2
Primary settling tank
Determinants:
a)
pH
b)
Electrical Conductivity
c)
Suspended Solids
d)
Ammonia as NH4
e)
Nitrate as NO3
f)
Phosphates as P
g)
Chemical Oxygen Demand
h)
Total Kelhdal nitrogen mg/l
Samples:
1.3
mS/m
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mS/m
mg/l
mg/l
mg/l
mg/l
mg/l
Polishing Plant, Badenpho plant, new plant
Balancing Dam
Determinants:
a)
pH
b)
Electrical Conductivity
c)
Suspended Solids
d)
Ammonia as NH4
e)
Nitrate as NO3
f)
Phosphates as P
g)
Chemical Oxygen Demand
h)
Total Kelhdal nitrogen mg/l
mS/m
mg/l
mg/l
mg/l
mg/l
mg/l
-
53 -
Amount of Samples
Amount of Analyses
DAILY
5
40
1.4
Final Effluent from each reactor
(i)
Badenpho plant
(ii)
Polishing plant
(iii)
Reactor A
(iv)
Reactor B
PER ANNUM
1300
10400
Determinants
a)
b)
c)
d)
e)
f)
g)
pH
Electrical Conductivity
Suspended Solids
Ammonia as NH4
Nitrate as NO3
Phosphates as P
Chemical Oxygen Demand
Amount of Samples
Amount of Analyses
1.5
mS/m
mg/l
mg/l
mg/l
mg/l
mg/l
DAILY
4
28
PER ANNUM
1040
7308
Total Daily Samples and Analyses for Operational purposes
Amount of samples per annum
:
2340
Amount of analyses per annum
:
17708
-
54 -
2.
WEEKLY OPERATIONAL SAMPLES
a)
b)
c)
i)
ii)
iii)
iv)
Anaerobic zone
Anoxic zone
Aeration zone
Badenpho plant
Polishing plant
Reactor A
Reactor B
Determinants
a)
b)
c)
d)
e)
f)
pH
Conductivity
Suspended Solids
Ammonia as NH4
Nitrate as NO3
Phosphates as P
Amount of Samples
Amount of Analyses
3.
mS/m
mg/l
mg/l
mg/l
mg/l
PER WEEK
4
24
PER ANNUM
108
648
BI WEEKLY SAMPLES:
Micro Biological Analyses of Filamentous Bacteria present in Mixed Liquor Suspended Solids.
i.
ii.
iii.
iv.
Reactor A
Reactor B
Badenpho Plant
Polishing Plant.
Amount of Samples
Amount of Analyses
BI - WEEK
4
16
PER ANNUM
104
516
Total Amount of Operational Samples
:
2553
Total Amount of operational analyses
:
18872
-
55 -
ADDENDUM A:
1.
ANALYSIS OF FINAL EFFLUENT 1 JULY 2010 TO 30 JUNE 2011
Microbiological Compliance:
 E. coli
Number of Determinations:
Number of Determinations Comply:
% Compliance:
2.
339
339
100 %
Physical Compliance:
 pH
Number of Determinants:
Number of Determinations Comply:
% Compliance
358
358
100 %
 Electrical Conductivity
Number of Determinants:
Number of Determinations Comply:
% Compliance
355
355
100 %
 Suspended Solids
Number of Determinants:
Number of Determinations Comply:
% Compliance
357
357
100 %
3. Total Physical Compliance
100 %
Or
358 + 358 + 337 = 1050 = 100%
358 + 358 + 337
1050
-
56 -
4.
Chemical Compliance:
 Chemical Oxygen Demand
Number of Determinants:
Number of Determinations Comply:
% Compliance
 Ammonia (N)
Number of Determinants:
Number of Determinations Comply:
% Compliance
 Nitrate Nitrite (N)
Number of Determinants:
Number of Determinations Comply:
% Compliance
 Phosphate (P)
Number of Determinants:
Number of Determinations Comply:
% Compliance
357
357
100 %
358
342
95.53 %
329
329
100 %
310
307
99.03 %
5. Total Chemical Compliance
100 % + 95.53 % + 100 % + 99.03 % = 98.64 %
Or
357 + 342 + 329 + 307 = 1050 = 98.6%
357 + 358 + 329 + 310
1050
6.
Average Compliance:
Microbiological + Physical + Chemical/3
100 % +
100 % +
98.6 %
= 298.6
3
3
=99.53%
Or
339 + 1050 + 1335 x 100 % = 2724
= 99.31 %
339 + 1050 + 1354
2743
-
57 -
ADDENDUM B:
1.
SAMPLING POINTS
CATCHMENT WATER SAMPLING POINTS
-
58 -
2
3
1
6
4
5
9
10
11
12
-
59 -
1.
Wonderfontein Spruit at Muiskraal
a.
Coordinates: latitude: -26.43644 longitude: 27.15112
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (µg/l)
Copper (µg/l)
d.
Iron (µg/l)
Magnesium (mg/l)
Manganese (µg/l)
Hardness (mg/l)
Zinc (mg/) (once a month)
Arsenic (µg/l)
Cadmium (µg/l)
Lead (µg/l)
Mercury (µg/l)
Nickel (µg/l)
Uranium (µg/l)
Antimony (µg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
Determination of mine related pollution and pollution by untreated sewage. If pollution is detected
further investigation upstream of sampling point is undertaken. Pollution of the Turfontein
compartment is also detected at this point.
-
60 -
2.
Mooiriver at Muiskraal
a.
Coordinates: latitude: -26.44507 longitude: 27.11834
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mSm)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (µg/l)
Copper (µg/l)
d.
Iron (µg/l)
Magnesium (mg/l)
Manganese (µg/l)
Hardness (mg/l)
Zinc (mg/) (once a month)
Arsenic (µg/l)
Cadmium (µg/l)
Lead (µg/l)
Mercury (µg/l)
Nickel (µg/l)
Uranium (µg/l)
Antimony (µg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
Testing is done to determine possible agricultural pollution. (Feedlots and fertilizer pollution). If
pollution is detected further investigation is carried out and DWA pollution control is alerted.
-
61 -
3.
Inlet to Boskopdam
a.
Coordinates: latitude: -26.51459 longitude: 27.12454
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (µg/l)
Copper (µg/l)
d.
Iron (µg/l)
Magnesium (mg/l)
Manganese (µg/l)
Hardness (mg/l)
Zinc (mg/) (once a month)
Arsenic (µg/l)
Cadmium (µg/l)
Lead (µg/l)
Mercury (µg/l)
Nickel (µg/l)
Uranium (µg/l)
Antimony (µg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
Determine pollution incidents between points 1 and 2 and 3 also influence of water from the
Gerhard Minnebron and Katdoringbos eyes.
-
62 -
4.
Boskop Dam Canal
a.
Coordinates: latitude: -26.66231 longitude: 27.08547
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (µg/l)
Copper (µg/l)
d.
Iron (µg/l)
Magnesium (mg/l)
Manganese (µg/l)
Hardness (mg/l)
Zinc (mg/) (once a month)
Arsenic (µg/l)
Cadmium (µg/l)
Lead (µg/l)
Mercury (µg/l)
Nickel (µg/l)
Uranium (µg/l)
Antimony (µg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
If pollution by Denel (old Naschem) takes place this point will reflect the incidence.
-
63 -
5.
Potchefstroom Dam
a.
Coordinates: latitude: -26.66339 longitude: 27.08654
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (µg/l)
Copper (µg/l)
d.
Iron (µg/l)
Magnesium (mg/l)
Manganese (µg/l)
Hardness (mg/l)
Zinc (mg/) (once a month)
Arsenic (µg/l)
Cadmium (µg/l)
Lead (µg/l)
Mercury (µg/l)
Nickel (µg/l)
Uranium (µg/l)
Antimony (µg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
Pollution between Boskopdam and Potchefstroom dam by agricultural activities will reflect in this
sample.
-
64 -
6.
Gerhard Minnebron
a.
Coordinates: latitude: -26.51337 longitude: 27.12822
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (µg/l)
Copper (µg/l)
d.
Iron (µg/l)
Magnesium (mg/l)
Manganese (µg/l)
Hardness (mg/l)
Zinc (mg/) (once a month)
Arsenic (µg/l)
Cadmium (µg/l)
Lead (µg/l)
Mercury (µg/l)
Nickel (µg/l)
Uranium (µg/l)
Antimony (µg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
Gerhard Minnebron flows from the Boskop compartment. This sample will indicate pollution by the
mines of this compartment.
-
65 -
9.
Mooirivier at Retief Street Bridge (Before Final Effluent)
a.
Coordinates: latitude: -26.70789 longitude: 27.10552
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia as N (mg/l)
Nitrate as N (mg/l)
Phosphate as P (mg/l)
Sulphate (mg/l)
Chloride (mg/l)
d.
Fluoride (mg/l)
Calcium (mg/l)
Chromium (mg/l)
Copper (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Hardness (mg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
This point is sampled to determine the contribution of Wasgoedspruit to the pollution of the Mooi
River.
-
66 -
10.
Mooirivier at South Bridge Viljoenskroon Road (Above Final
Effluent)
a.
Coordinates: latitude: -26.75261 longitude: 27.10033
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia (mg/l)
Nitrate (mg/l)
Phosphate (mg/l)
Sulfate (mg/l)
Chloride (mg/l)
d.
Fluoride (mg/l)
Calcium (mg/l)
Chromium (mg/l)
Copper (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Hardness (mg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
The influence of the Potchefstroom City and the Loopspruit is determined at this point.
-
67 -
Final Sewage Effluent at Sewage Plant
a.
Coordinates: latitude: -26.75141 longitude: 27.0945
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia (mg/l)
Nitrate (mg/l)
Phosphate (mg/l)
Sulfate (mg/l)
Chloride (mg/l)
Fluoride (mg/l)
Calcium (mg/l)
Chromium (mg/l)
Hardness (mg/l)
Arsenic (mg/l) (Biweekly)
d.
Copper (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Cadmium (mg/l) (Biweekly)
Lead (mg/l) (Biweekly)
Mercury (mg/l) (Biweekly)
Nickel (mg/l) (Biweekly)
Uranium (mg/l) (Biweekly)
Antimony (mg/l) (Biweekly)
Free Chlorine (mg/l)
Chemical Oxygen Demand (mg/l)
Aluminium (mg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
The contribution of the Tlokwe Waste Water Treatment Works to the Mooi River is determined at
this point.
-
68 -
11.
a.
Mooirivier 1km downstream of Final Sewage Effluent
Coordinates: latitude: -26.76401 longitude: 27.09139
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia (mg/l)
Nitrate (mg/l)
Phosphate (mg/l)
Sulfate (mg/l)
Chloride (mg/l)
d.
Fluoride (mg/l)
Calcium (mg/l)
Chromium (mg/l)
Copper (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Hardness (mg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
The influence of the final effluent on the Mooi River is determined at this point.
-
69 -
12.
Mooirivier at DWA Measuring Station at Kromdraai (Far Below Final
Effluent)
a.
Coordinates: latitude: -26.88041 longitude: 26.96432
b.
Frequency: Weekly sample
c.
Parameters tested:
pH
Suspended solids (mg/l)
Electrical Conductivity (mS/m)
Total dissolved solids (mg/l)
Turbidity (NTU)
Ammonia (mg/l)
Nitrate (mg/l)
Phosphate (mg/l)
Sulfate (mg/l)
Chloride (mg/l)
d.
Fluoride (mg/l)
Calcium (mg/l)
Chromium (mg/l)
Copper (mg/l)
Iron (mg/l)
Magnesium (mg/l)
Manganese (mg/l)
Hardness (mg/l)
Total Coliforms (Count/100ml)
E. coli (Count/100ml)
Reason for sampling:
Influence of agricultural activities in this section of the catchment will be indicated in the samples at
this point.
-
70 -
WASTE WATER TREATMENT WORKS RISK ABATEMENT PLAN NOVEMBER 2011
REVISIONS
VERSION 1.0
DATE
14 December 2011
Approved and signed on this day ________ of December 2011 at Potchefstroom.
1. ________________________
MR. SANDILE TYATYA
MUNICIPAL MANAGER
TLOKWE CITY COUNCIL
2. ____________________________
MR. PC LABUSCHAGNE
MANAGER
DEPARTMENT
COMMUNITY SERVICES
3. _______________________
MR. C STOLTZ
ACTING MANAGER
DEPARTMENT
INFRASTRUCTURE
4. _____________________________
MR. JF KLEINHANS
WATER SERVICE MANAGER
(ENGINEER)
5. _________________________
MR. BCK NELL
WATER QUALITY MONITORING
MANAGER (CHIEF CHEMIST)
6. ____________________________
S THOMAS
FARMER REPRESENTATIVE
7. _________________________
MR. L CALDWELL
DEPARTMENT WATER AFFAIRS
8. ____________________________
LANCE CARSON
SUPERINTENDENT RETICULATION
SYSTEMS
-
71 -