WASTEWATER TREATMENTWASTEWATER TREATMENT

Lecture notes for 22nd of SeptemberLecture notes for 22nd of September

Dr. Pál Mihátz (Fac. of Chem. Eng.)

Dr. István Licskó and Anita Szabó (Dep. of Sanitary and Environ. Eng., Fac. of Civil Eng.

• Earth is very rich in water: >70% of the planet`s surface

• More than 97 % of this is salt water

• 30 % of the world`s renewable fresh water supplies are already being used

• Enough fresh water is available to support over 20 billion people, if it was evenly distributed.

• Because of variable climatic and geologic condition it is available to 6 billion people.

WATERWATER

Salt water in oceans and seas 97,4%

Groundwater0,59%

Ice caps and glaciers

1,98%Lakes

0,007%

Soil moisture 0,005%

Atmosphere, rivers, plants, animals

0,001%

Fresh water

2,6%

0,014%

WATER RESOURCESWATER RESOURCES

THE HYDROLOGIC WATER CYCLETHE HYDROLOGIC WATER CYCLE

infiltration

Groundwaterflow

SOCIAL WATER CYCLESOCIAL WATER CYCLE

• Diversion, abstraction

• Water use (domestic, communal, industrial, agricultural)

• Effluent drainage (return to natural recipient)

• On-site (non-diversion) water uses (transportation, recreation)

WATER SOURCESWATER SOURCES

Subsurface waters:

ground water

water of deep confined aquifers

karstic water

bank filtered water

Surface waters:

river

lake

reservoir

WATER USESWATER USES

• drinking water

• irrigation

• industrial

• fish ponds

• recreation

• shipping

• nature reserve

Other aspect:

1. Domestic - water for drinking, cooking, personal hygiene, lawn sprinkling, etc.

2. Public - water for fire protection and street cleaning and water used in schools or other public buildings

3. Commercial and Industrial - water used by restaurants, laundries, manufacturing operations, etc.

4. Loss - due to leaks in mains and house plumbing fixtures

WATER DEMANDWATER DEMAND

human’s need (2-4 l/day)

agriculture (41% of the water)

cool power generators (38%)

industrial manufacturing (11%)

USA (1993)

WATERWATER

• 30% of the world’s people have inadequate sanitation

• Consequence: cholera, typhoid, hepatitis, etc.

• 25 million deaths annually are caused by water pollution (mostly infants)

• Damage to aquatic ecosystem

POLLUTANTS IN WASTEWATERPOLLUTANTS IN WASTEWATER

•different size–dissolved <0.01 m–colloidal 0.01-1.0 m–suspended 1.0-100 m–settleable suspended solids >100 m

•inorganic–mainly dissolved–conventional components

•salt content

•sulphate

–inorganic micropollutants•Heavy metals (Hg, Cd, Pb, Cr, Ni, Cu, Zn, Ag, etc.)

•As, CN-, Sb

THE ROLE OF CONCENTRATIONTHE ROLE OF CONCENTRATION

•All components can be–Toxic matter–Stimulating matter (trace elements)

depending on concentration

(Pick salami can also be toxic!!! (if you eat that much))

WHAT IS WATER POLLUTION?WHAT IS WATER POLLUTION?

• Along its path through the hydrologic cycle, the water is polluted by natural (animal, plant) and anthropogenic factors

• Type of pollutants in a certain catchment depends on:–Geochemistry–Meteorology–Topography–Ecology

• Type of pollution entrained along the social water cycle depends on the type and technological level of the particular human activities

WHAT IS WATER POLLUTION?WHAT IS WATER POLLUTION?

• In a particular catchment, at a particular point and at a particular time the level of the pollution is the result of the interactions of the natural and social water cycles

• Definition (Klein, 1972, Felföldy, 1974)

Water pollution is understood to include all impacts, as a result of which the quality of water is changed in a manner to make it less suited, or completely unsuited to human use and to sustain natural biological processes occurring in it.

WATER QUALITY MANAGEMENTWATER QUALITY MANAGEMENT

• Water quality = sum of different properties of water

• Classification of water • water use = certain objective to reach• parameters (physical, chemical, biological,

bacteriological)

C

B

DA

wastewater

Industry

Recreation

wastewater

Environmental protection

DEFINITIONSDEFINITIONS

EMISSION (E) = input load = the amount of pollutant discharged in a unit of time [M/T]

C

B

DA

wastewater

Industry

wastewater

E (kg/d)

I (kg/m3)

I (kg/m3)

E (kg/d)

DEFINITIONSDEFINITIONS

IMISSION (I) = pollutant concentration developed as the effect of pollutant load = effect of emission [M/L3]

C

B

DA

wastewater

Industry

wastewater

E (kg/d)

I (kg/m3)

I (kg/m3)

E (kg/d)

WATER POLLUTION CONTROLWATER POLLUTION CONTROL

• The level of water pollution can be controlled by engineering measures implemented along the natural and social cycles. Interference with the natural cycle has triggered recently violent oppositions in some groups of society and political parties (green movements), as a consequence of which the only viable alternative of pollution control will comprise engineering, economic and legal measures along the social water cycle in the foreseeable future already.

• Definition the required component concentrations at the selected river section

WATER QUALITY MANAGEMENTWATER QUALITY MANAGEMENT

if water quality is not good enough

action is needed

» science

» technology

» economy + legislation

defence

preventionactivityactivity

pollutant loadpollutant load

water qualitywater quality

ecosystemecosystem

monitoringmonitoring

water usewater use

strategies + alternative proposalsstrategies + alternative proposals

classificationclassification

trendstrends

causes and consequencescauses and consequences

decisiondecision -technology-economy

-legislation

requirementsrequirements

(limiting values /standards)

interventionintervention

modellingmodelling

TOOLS OF WATER POLLUTION CONTROLTOOLS OF WATER POLLUTION CONTROL

• Engineering measures

• Legal measures

• institutional

ENGINEERING ENGINEERING MEASURES AGAINST POLLUTIONMEASURES AGAINST POLLUTION

• end of pipe solutions (decreasing load at the end of the technology = WASTEWATER TREATMENT)

• changing the technology (increasing effectivity)• changing inputs (other types of raw materials)• changing the product• increasing re-use• changing the location of discharge point (receiving water

body)• changing the capacity of environment (reservoirs)• changing the time of discharge (storage of polluted water)• dilution• other methods (aeration, etc.)

LEGAL MEASURESLEGAL MEASURES

• Water Act, Environmental Act

• Effluent quality standards

• Fines

• Economic aspects

INSTITUTIONALINSTITUTIONAL

• Monitoring

• Evaluation

• Declarations

• Wastewater

used water originated from human activity (including metabolism)

contains pollutants

WASTEWATERWASTEWATER

• Pollutants

The matters entering to the recipient that change the existing biological, biochemical processes significantly; and deteriorate or prohibit the further water use

• Wastewater treatment

Decreasing the pollutant concentration of wastewaters before entering into the recipient

WASTEWATERWASTEWATER TREATMENT TREATMENT

• Possible recipients

• Surface water

• Subsurface water

• Soil

•DOMESTIC WASTEWATER (sewage)

human wastes and washwater from homes

•INSTITUTIONAL WASTEWATER (sewage)

human wastes and washwater from public buildings, commercial establishments

•MUNICIPAL SEWAGE

mixture of sewage and industrial wastewater

•INDUSTRIAL SEWAGE

used water from manufacturing processes - contains different chemical compounds

•AGRICULTURAL WASTEWATER (e.g. liquid manure)

•STORMWATER

surface runoff caused by rainfall - carries organics, suspended and dissolved solids, etc.

TYPES OF TYPES OF WASTEWATERWASTEWATERSS

• domestic and institutional wastewaters (sewage)

Volume depends on the use of drinking water. The volume of the drinking water use depends on technical and cultural level of population, country, region, settlement.

Industrialised countries: 100-160 liter/person/d

Developing countries: <<100 liter/person/d

Hungary: 90-100 liter/person/d (Budapest: 180 liter/person/d)

•industrial wastewaters

Volume depends on the type of industry, number of factories, workshops, the level of applied technology, etc.

Cooling water, wastewaters from metallurgy, chemical industry, food industry, etc.

WASTEWATERWASTEWATER VOLUMES VOLUMES

• agricultural wastewaters

Liquid manure (pig farms, cow farms, poultry farms)

Volume depends on the types of the farm, number of animals, technology level, educational level of employees, etc

• municipal wastewaters

Sewage water + industrial wastewater + infiltration (exfiltration)

Infiltration: 5-40%

Exfiltration: 5-15%

WASTEWATERWASTEWATER VOLUMES VOLUMES

COMPOSITION & VOLUME OF COMPOSITION & VOLUME OF MUNICIPAL MUNICIPAL WASTEWATERSWASTEWATERS

•VERY HIGH VARIATION

–TYPE OF COMMUNITY•RESIDENTAL AREA

•RECREATIONAL AREA

•OFFICES

–TYPE OF INDUSTRIES

–AMOUNT OF SURFACE WATER (TYPE OF COLLECTION SYSTEM)

–DIFFERENT HABITS•EATING

•TYPE OF DETERGENTS

YEARLY VARIATIONYEARLY VARIATION

HYDRAULIC LOAD OF N. WWTP. (MONTHLY AVERAGE)

8 000

10 000

12 000

14 000

16 000

18 000

20 000

22 000

199

0

199

1

199

2

199

3

199

4

199

5

199

6

199

7

199

8

199

9

200

0

DATE

HY

DR

AU

LIC

LO

AD

[m

3/d

]

VARIATION WITHIN A YEARVARIATION WITHIN A YEAR

HYDRAULIC LOAD OF N. WWTP. 1999

700080009000

1000011000120001300014000150001600017000

jan

.

feb

r.

mar

ch

apr.

may

jun

e

july

aug.

sep

t.

oct.

nov

.

dec

.

DATE

HY

DR

AU

LIC

LO

AD

[m

3 /d]

VARIATION WITHIN A DAYVARIATION WITHIN A DAY

7 21Time [h]

Con

sum

pti

on o

r h

ydra

uli

c lo

ad [

m3/

h]

20%

30%

40%

50%

60%

70%

80%

90%

100%19

75

1980

1985

1990

1991

1992

1993

1994

1995

1997

Date

Per

cent

age

of t

otal

pop

ulat

ion

Populationconnected todrinking watersuplly system

Populationconnected tosewer system

Hungary

UTILITY GAPUTILITY GAP

50%