This document discusses wastewater treatment and pollution. It covers the constituents of wastewater, including microorganisms, solids, inorganic and organic matter. It discusses the measurement of biochemical oxygen demand and describes municipal, industrial, and stormwater wastewater. The effects of water pollutants are outlined. Methods of wastewater collection and different types of sewer systems are summarized. Biological and physical/chemical wastewater treatment plants and processes are briefly described.

2. SUBTOPICS:
1. Wastewater
2. Pollution of
Receiving Water
3. Wastewater
Collection
Reporter: Salinas

3. SUBTOPICS:
1. Principles of
Wastewater
Treatment
2. Land-Based
Treatment
Reporter: Japin

4. SUBTOPICS:
1. Wastewater
Treatment
Plants
Reporter: Orlanes

5. SUBTOPICS:
1. On-Site
Treatment
Facilities
2. Government /
Public Role in
Pollution Control
Reporter: Real

6. 12.2 WASTEWATER
Wastewater can be formed by a variety of
activities, including washing, bathing, and using
the toilet. Rainwater runoff is also considered
wastewater. No matter where it comes from, this
water is full of bacteria, chemicals, and other
contaminants.
What is Wastewater Treatment?
Wastewater treatment is the process of taking
wastewater and making it suitable for discharge
back into the environment. Wastewater treatment
reduces the contaminants to acceptable levels so as
to be safe for discharge into the environment.

7. 12.2.1 CONSTITUENTS
1. Microorganism
2. Solids
- Total Solids
- Inorganic Constituents
- Organic Matter
Inorganic constituents of wastewater includes:
1. Chlorides & Sulfates
2. Nitrogen & Phosphorus
3. Carbonates & Bicarbonates
4. Toxic Substances

8. Organic Matter includes:
1. Protein
2. Carbohydrates
The sources of these biodegradable
contaminants include excreta and urine
from humans: food wastes from sinks:
soil and dirt from bathing, washing,
laundering: plus various soaps,
detergents, and other cleaning
products.

9. 12.2.2 BOD MEASUREMENT
The amount of organic matter in water
or wastewater can be measured directly
(as TOC),but this doesn’t tell us
whether the organics are biodegradable
or not. TOC is determined by measuring
the amount of CO2 produced when the
produced when the organic carbon in the
sample is oxidized by a strong oxidizer
and comparing it with the amount in a
standard of known TOC.

10. Figure 12-1
Total Organic
Carbon Analyzer
Current
model of an
automatic
analyzer in w/c
chemical
oxidation is used
to determine the
TOC in water and
wastewater.

11. 12.2.2 BOD MEASUREMENT
kt kt
L L0 (10 ) and L 0
L L (1 10
0
)
Where:
L = carbonaceous BOD remaining at time t = t (O2 needed
to oxidize carbonaceous organic matter remaining).
L0 = ultimate carbonaceous oxygen demand (i.e. ultimate
BOD; O2 needed to oxidize carbonaceous organic matter
initially present).
L0 – L = carbonaceous oxygen demand (i.e. BOD
satisfied; O2 used to oxidize carbonaceous organic
matter at time t = t.
t = time (days)
k = rate constant (base 10) (day -1)

12. 12.2.3 Municipal Wastewater
The excreted waste from humans
is called sanitary sewage.
Wastewater form residential areas,
referred to as domestic sewage,
includes kitchen, bath, laundry, and
floor drain wastes. These, together
with the liquid wastes from
commercial and industrial
establishments, are termed municipal
wastewater.

13. 12.2.3 Industrial Wastewater
Wastewater from industries include
employees’ sanitary wastes, process wastes
from manufacturing, wash waters, and
relatively uncontaminated water from
heating and cooling operations.
12.2.3 Stormwater
The runoff from rainfall, snowmelt,
and street washing. It is less
contaminated than municipal wastewater.

14. 12.3 POLLUTION OF RECEIVING WATERS
12.3.1 Effects of Pollutants
Water pollution occurs when the
discharge of wastes impairs water quality
or disturbs the natural ecological
balance.
The contaminants that cause problems includes:
1. Pathogens
2. Organic Matter
3. Solids
4. Nutrients
5. Toxic & Hazardous Substances
6. Other Pollutants (color, foam, heat, &
radioactive materials.

15. 12.4 WASTEWATER COLLECTION
1. Early Systems
2. Present Systems
Present Systems
Sewage collection systems today
normally consist of separate storm
and sanitary sewers in the newer
areas and combined sewers in the
older sections of cities.

16. 3 Types of Sewers
1. Sanitary Sewers
Sanitary sewers carry domestic sewage, liquid
commercial and industrial wastes, and
undesirable contributions from infiltration and
storm water.
2. Storm Sewers
Storm sewers receive storm water runoff from
roads, roofs, lawns, & other surfaces.
3. Combined Sewers
Combined sewers perform the functions of
sanitary and storm sewers and are common in the
older section of most municipalities because
these sewers carry sanitary wastes and are
connected to basement floor drains, any
surcharging could cause a backup of untreated
sanitary sewage into basements.

17. There are two types of wastewater
treatment systems:
1.Biological treatment plant , &
2.Physical/Chemical treatment plant

20. Commonly used chemical processes for
industrial wastewater treatment:
1.Oxidation
2.Reduction
3.Precipitation
4.Neutralization
Commonly used chemical processes for
municipal wastewater treatment:
1.Disinfection
2.Precipitation

21. Physical processes of wastewater treatment:
1.Removing grit
2.Clarifyinhg raw sewage & concentrating
the settled solids
4.Clarifying biological suspensions &
concentrating the settled floc
5.Gravity thickening of primary or
secondary sludges

22. Impounded System:
1.Wetlands
2.Aerated Lagoons
3.Anaerobic Lagoons
4.Aerated Ponds
5.Facultative Ponds
Advantages of Land based Treatment
Methods Over Wastewater Treatment Plants:
1.Characterized Simplicity
2.Lower Operating Cost
3.Lower Capital Cost

23. Regarded as Practical Cutlets for
the Disposal of Treated or
Untreated Wastewater:
1.Streams
2.Lakes
3.Rivers
4.Oceans

24. Factors that Influence the Decision in
Choosing a Suitable Wastewater
Treatment Method:
1.Local Preference
2.Experience of the consultant based on
engineering methods
3.Wastewater process/track record of
the process
Options in Dealing with the Organic &
Inorganic Contaminants:
1.Removed physically
2.Converted biologically
3.Changed chemically

25. Objective of Land Application System
The objective of the land based
treatment was to reduce waste
discharged to surface waters while
utilizing the nutrient content for
crops and encourage the used of
effluent for irrigation and ground
water recharge.

26. Permeable Soil – a type soil having
pores or openings that permits
liquids or gases to pass through.
Impervious soil – an impenetrable
soil.
Sludge – the substances that are
removed during water treatment.

27. Permeable Soil – a type soil having
pores or openings that permits
liquids or gases to pass through.
Impervious soil – an impenetrable
soil.
Sludge – the substances that are
removed during water treatment.