dr.- ing. rainer-werner abendt nuremberg contact: rainer.abendt@gmx.de

®Rainer Abendt

Dr.- Ing. Rainer-Werner AbendtNuremberg

Contact: rainer.abendt@gmx.de

Wastewater Workshop in Nairobi 29-th August till 03-rd September 2011

Sewer Systems

®Rainer Abendt

A Recap of the previous module indicated that:-

Sewage purification systems are necessary for health. Because supply of clean water to the population is indispensable for health provision. (National Water Services)

But sewage systems are also important for protection of groundwater or river water.

Why?

Because we need river or ground water to produce drinking water !

Sewer Systems

®Rainer Abendt

Sewer Systems

Sources of raw water in Bavaria

Millions. m³/yr

% value

groundwater from wells 700.7 74,8

groundwater from springs 163.8 17,5

bank filtrate, recharged groundwater 48.3 5,1

surface water 24.2 2,6

Total 937.1 100

®Rainer Abendt

Effluent Standards (emission)

Water Quality Standards (imission)

Education Standards: labours and academic

Health and Safety Standards

2

1

1

2

3

43

4

Sewer Systems

®Rainer Abendt

Treatment plant

Urban area

Evolution of water crowd:

- Sewer construction

Evolution in sewer network:- By-laws

Evolution of Water quality:

- Sewer operation

First step!

Without Stormwater Drainage

-auslässeLegal Orders

Sewer Systems

®Rainer Abendt

Treatment plant

Urban area

Evolution of water crowd:

- Sewer construction

Evolution in sewer network:- By-laws

Evolution of Water quality:

- Sewer operation

Or First step!

With separate Stormwater Drainage

Effluent in a river

-auslässeLegal Orders

-auslässeLegal Orders

Sewer Systems

®Rainer Abendt

Are the stormwater drains connected to the trunk sewer?

If not, where does the stormwater drain to?

Urban area

Evolution of water crowd:

- Sewer construction

Evolution in sewer network:- By-laws

Evolution of Water quality:

- Sewer operation

Storm- and Wastwater mixed

Stormwater Effluents

Treatment plant

-auslässeLegal Orders

-auslässeLegal Orders

Or First step!

Sewer Systems

®Rainer Abendt

Wastewater disposal(Discharge and treatment)

Administration:

Finances;

Personnel

By-laws:

Connection approval;Industrial monitoring;Cost covering

Sewer construction:

General drainage;Sewer network expansion;Sewer operation:

Maintenance, repair, operation/control of storage space and outlets (provisions under water law)

Sewer Systems

®Rainer Abendt

Sewer Systems

• Pipe Varieties in Nuremberg, Germany.

These are examples of types of pipes needed for various transmission works

In selecting a pipe material for sewer service, the design engineer must evaluate standards for materials, products and systems

The standards must meet international specifications and must have passed Proficiency Testing Programs for quality assurance.

®Rainer Abendt

Technical Standards of Materials

Product &Testing Standards guarantee quality.Check the:-pipe diameterPipe MaterialPipe thickness

Sewer Systems

®Rainer Abendt

First WASPA Annual International Conference 8-9th September 2011, KICC Grounds, Nairobi, Kenya

DEN = Technical European Norms

Free trade

®Rainer Abendt

Examples of Standards Quality of on Water Materials:

CEN TC 155 „Plastics piping systems“ “

CEN TC 163 „Sanitary appliances “

CEN TC 164 „Water supply “

CEN TC 165 „Waste Water Engineering“

CEN TC 203 „Cast iron pipes “

CEN TC 208 „Elastomeric seals“

CEN TC 230 „Water analysis “

CEN TC 308 „Characterization of sludges“

Sewer Systems

®Rainer Abendt

Example: ‘Visual inspection coding system,

Sewer Systems

®Rainer Abendt

Wastewater types (QWW):1. Domestic wastewater (QD) such as: shower water

swimming pool water flushing water

faecal water2. Commercial and/or industrial wastewater (QInd)

such as: production water treatment water cooling water

3. Infiltration water (QIW)4. Stormwater (rainfall) (QR)5. Melt water

Daily amount of wastewater, normal in Europe:average: 125 - 200 l / (per individuaI per day)frequently: > 300 l / (per individual per day) due to increased amounts of

infiltration water (QIW)

Sewer Systems

®Rainer Abendt

Parameters in Wastewater pollution (raw sewage):

Inhabitant-related loads in raw wastewaterBOD5 : 60 g/(per Individual per day)COD: 120 g/(per Individual per day)filterable solids: 70 g/(per individual per day)Ptot: 1.8 g/(per individual per day)Ntot: 11 g/(per individual per day)Ntot in raw wastewater mainly as TKNTKN (Total Kjeldahl Nitrogen): Norg + (NH4

+ - N)undissolved matter: 30 %dissolved matter: 70 %

Sewer Systems

®Rainer Abendt

Sewer Systems

Wastewater pollution (raw sewage):

Concentrations of minimum parameters in domestic raw wastewater:

BOD5: 200 - 400 mg/l

COD: 400 - 800 mg/lPtot: 5 - 12 mg/l

Ntot: 30 - 75 mg/l

®Rainer Abendt

The wastewater discharged into the sewer system should not possess the following characteristics:

1. Free acids (pH values < 6.5) and strong lyes (pH > 8.5)2. Salts in high concentrations3. Strong poisons (toxic substances, e.g. Cu ions)4. Oils and greases (mineral oils)5. Hazardous and explosive gases (e.g. methane, petrol

fumes)6. Odorous substances (e.g. sulphides from leather

processing)7. Large quantities of suspended or heavy settleable solids8. Radioactive substances (e.g. from hospitals)9. High Temperatures (over 35 °C)10. Heavy discoloration (e.g. from the textile processing

industry)

Sewer Systems

®Rainer Abendt

Sewer Systems

t [h]

Q [l/s]%

200

150

100

50

0

190

180

170

160

140

130

120

110

90

80

70

60

40

30

20

10

5.00 5.009.00 13.00 17.00 21.00 1.00

Reserve für Regenwasser, Q

SchmutzwasserQ

FremdwasserQ

QKW

RW

FW

SW

The daily variation of waste water %

Wastewater

Infiltration Water

Pipe capacity for stormwater

®Rainer Abendt

Sewer Systems

Cost Reduction:

You can reduce your treatment costs, if you ensure non-soiled wastewater does reach the sewer network at all.

In a mixed sewer net (rain and wastewater) you can reduce your costs by building a storm water tank at a quarter the distance from the start of the trunk sewer with a drain time of 10 to 15 minutes in the channel.

®Rainer Abendt

Sewer network of NurembergTreatment plants

Sewer network

Stormwater tank

Sewer Systems

®Rainer Abendt

Sewer Systems

Schematic profile

®Rainer Abendt

Sewer Systems

Diagram

®Rainer Abendt

Water quality of the river

Sewer Systems

®Rainer Abendt

Demands on water quality (Europe):Demands on water quality (Europe):

COD

BOD5

Ammonia Ntot

PtotSuspended Solid

Why Sewage Purification ?

®Rainer Abendt

Laboratory

operating data

Demands on the sludge

Legal orders

Secure disposal

Government control

Automatic monitoring

Legal orders

Treatmentplant

(Process system)

Product 2 "Sludge"

Product 1 „Clean Water"Urban area

Evolution of water crowd:

- Sewer construction

Evolution in sewer network:- By-laws

Evolution of Water quality:

- Sewer operation

Administration

Personnel

Documentation

Financialmanagement

Sewer Systems

?

®Rainer Abendt

How then does a

Treatment Plant look like ?

Sewer Systems