Introduction to Environmental Engineering.pptx

Environmental Engineering
Engr. Lorenz Esperon Borromeo
lorenz.borromeo@upd.edu.ph

Environmental Engineering
Environmental Engineering is manifest by sound engineering thought and practice in the
solution of problems of environmental sanitation, notably in the provision of safe, palatable and
ample public water supplies; the proper disposal of or recycle of wastewater and solid wastes;
the adequate drainaige of urban and rural areas for proper sanitation; and the control of water,
soil and atmospheric pollution, and the social and environmental impact of these solutions
(ASCE,1977)

Fields of Environmental Engineering
Environmental Impact Assessment
The process of predicting the likely environmental consequences of implementing a project &
designing appropriate preventive mitigating & enhancement measures as an input to decision
making.
Water Supply and Transport
Develop a systems to store, treat, convey water for various uses
Wastewater Conveyance and Treatment
Develop collection and treatment systems to carry this waste material away from where people
live and produce the waste and discharge it into the environment

Fields of Environmental Engineering
Air Quality Management
Design of manufacturing and combustion processes to reduce air pollutant emissions to
acceptable levels

Water Classification
Depends on the uses of water, namely for domestic, industrial,
irrigation, transportation, habitat for marine life etc.
Streams are classified according to the highest beneficial use that can
be obtained from them.
*Revised Water Usage and Classification- DENR Administrative Order
No. 34 Series of 1990.
*Revised Effluent Regulations of 1990- DENR Administrative Order
No. 35 Series of 1990
*DAO 2016-08. For key changes, refer to the handout.

Characteristics of Wastewater
A. Physical Characteristics
Color
Odor
Turbidity
Temperature
Total Solids
B. Chemical Characteristics
pH Phenols
Hardness Pesticides and Agri Chemicals
Nutrients
Trace Metals
Proteins
Carbohydrates
Oils, Fats and Greases
Surfactants

Characteristics of Wastewater
C. Biological Characteristics
Measures of Oxygen Demand
◦ DO
◦ ThOD
◦ BOD
◦ COD
Kinetics of BOD

Color
Varies according to the type of industry.
It is generally an indication of its age.

Color
Color is measured by comparison with standards using:
Visual Comparison Method
Nessler Tubes/Nessler Cylinders – Standardized glass tubes for filling with standard solution
colors for visual color comparison with similar tubes filled with solution samples.
Photoelectric Colorimeters/Spectrophotometers - Colorimeter that uses a phototube or
photocell, a set of color filters, an amplifier, and an indicating meter for quantitative
determination of color.

Odor
Odors are usually caused by gases produced by the decomposition of organic matter or by the
substances added to the wastewater.

Odor
Olfactometer - device used to measure odour intensity, and concentrations of volatile organic
compounds, by means of their smell.

Turbidity
A measure of the light-transmitting properties of water, is another test used to indicate the
quality of wastewater discharges and natural waters with respect to colloidal and residual
suspended matter.
Nephelometer – measures the intensity of light scattered at 90 degrees as a beam of light passes
through a water sample.

Turbidity
Secchi Disk Depth – circular disk used to measure water transparency in oceans and lakes.
Units in turbidity; JTU, FTU, NTU

Temperature
High temperatures lower the solubility of oxygen in water and increase the rate at which
oxygen-consuming microbes attack organic waste.

Solids
0.45-2 micrometer filter
Drying at
103-105
deg C
Drying at
103-105
deg C
Ignition to high
temperatures
(500°C to 600°C)
Ignition to high
temperatures
(500°C to 600°C)
SS = Settleable Solids
TSS = Total Suspended Solids
TDS = Total Dissolved Solids
VSS = Volatile Suspended Solids
FSS = Fixed Suspended Solids
VDS = Volatile Dissolved Solids
FDS = Fixed Dissolved Solids
TVS = Total Volatile Solids
TFS = Total Fixed Solids
TS = Total Solids

pH
The term pH is used to describe the acid or base properties of water solutions.

Trace Metals
Heavy metals which are toxic even in small concentrations.
Mercury – causes minamata disease which is a neurological disease characterized by trembling,
inability to walk and speak and even serious convulsions that can lead to death.
Cadmium – responsible for the Itai-itai disease; an extremely painful disease that causes
disintegration of the bones.
Silver – causes argyria, the blue-gray discoloration of the skin and mucous membrane.
Arsenic – recognized poison; carcinogenic
Chromium – causes neurological disease
Lead – leads to fetal malformation, mental disability, irritability, loss of appetite, and reduction
of sex drive.

Dissolved Oxygen
Quantity of free molecular oxygen dissolved in the water.
Factors affecting DO:
Temperature
Surface Area
Velocity

Theoretical Oxygen Demand
Measure of the amount of oxygen needed to oxidize completely and organic matter whose
chemical formula is known.

Biological Oxygen Demand
Measure of the amount of oxygen needed by microorganism to decompose biodegradable
organics at a specified time (5 days), temperature (20 deg C) and pH 7.

Chemical Oxygen Demand
Measure of the amount of oxygen needed to oxidize organics using strong oxidizing agents,
usually KMnO4 or K2Cr2O7 in acid media.
Reflux for 2 hours at 150 deg C

Kinetics of BOD
Oxygen Cocn
Time
Lt
Lo-Lt
BODt
Lo
BOD
BODt=Lo(1-e-kt
)
At different temperatures:
kt=k20(Ɵ)(T-20)
Ɵ = 1.056 (20-30)
Ɵ = 1.135 (<20)
Ɵ = 1.047 (>30)
Sample k
Raw Sewage 0.35-0.70
Well-treated sewage 0.12-0.23
Factors affecting k:
1. Nature of the waste
2. Temperature
3. Ability of the organisms in the system
to utilize the waste

Types of Wastes
Oxygen Demanding Wastes
Inorganic Wastes
Synthetic Organic Wastes
Nutrients
Pathogenic Wastes
Radioactive Wastes
Thermal Wastes

Why do we treat wastes?
To remove organic matter from the sewage which causes pollution
To remove pathogens (disease causing organisms) which pose serious health risk

Pre-treatment
Pre-treatment process has a little effect in BOD reduction.
Bar Racks- to remove large objects that would damage or foul pumps, valves and other
mechanical equipment.
Grit Chambers- tanks used to remove grits. Grits are inert dense materials such as sand, broken
glass, silt and pebbles. (Type I Sedimentation-Dilutes, non-flocculent, free-settling)
Comminutors/Macerators- used to macerate wastewater solids by revolving cutting bars.
Equalization Basins-not a treatment method but a technique to improve the effectiveness of
both secondary and advanced wastewater treatment. Purpose is to dampen variations so that
the wastewater can be treated at a nearby constant flow thus reducing the size and cost of
treatment units.

Primary Treatment
Primary Sedimentation Basins- removal of raw sludge by gravity settling. Overflow rate is the
controlling parameter and hydraulic detention time.
Type II Sedimentation-Dilute, flocculent (particles can flocculate as they settle).

FACTORS AFFECTING SEDIMENTATION
•PARTICLE SIZE
The size and type of particles to be removed have a significant effect on the operation of the
sedimentation tank.
•WATER TEMPERATURE
Another factor to consider in the operation of a sedimentation basin is the temperature of the
water being treated. When the temperature decreases, the rate of settling becomes slower.
Primary Treatment

Secondary Treatment (Biological)
Secondary treatment process removes soluble BOD that escapes the primary treatment.
Aerobic Decomposition
molecular oxygen is the terminal electron acceptor.
products of decomposition: carbon dioxide, water and new cell material (more stable products)
large amount of energy released therefore high growth rates. Consequently, large production
of new cells. (More biological sludge)
decomposition is rapid, efficient, low odor potential

Anaerobic Decomposition
molecular oxygen and nitrate must not be present as terminal electron acceptors.
sulfates, carbon dioxide and other organic compounds can serve as T.E.A.
decomposition products: ammonia, hydrogen sulfides, methane, mercaptans etc
energy released is low, thus sludge production is low.
3 Step Process:
1. Hydrolysis- breakdown of high molecular weight organic compounds into a smaller chained
compounds.
2. Acidogenesis-formation of low molecular weight fatty acids
3. Methanogenesis- formation of methane from organic fatty acids.

Anoxic Decomposition
nitrate ion is the terminal electron acceptor.
oxidation by this route is called denitrification.
decomposition products: nitrogen gas, carbon dioxide, water and new cell material

Activated Sludge Process
Aerated for 6-8 hrs (8 cubic meters/cubic meter wastewater)
as the microorganisms grow and are mixed by the agitation of the air, they clump together
forming biological floc (activated sludge).
some of the settled sludge is return to the aeration tank (return sludge) to maintain the high
population of microbes that permits rapid breakdown. (20-30%)
amount of time that microorganisms are kept in the system is called mean cell residence time,
solids retention time or sludge age.

Trickling Filters
consists of bed of coarse material, such as stones or plastic materials (media) over which
wastewater is applied.
provide large amounts of surface area where the microorganisms cling and grow in a slime on
the rocks. (attached growth process)

Trickling Filters
Filter Media:
Crushed rock
Plastic media

Rotating Biological Contactors (RBC)
Provide media for the buildup of attached microbial growth.
Bring growth into contact with the wastewater.
Aerate the wastewater and the suspended microbial growth in the reservoir.

Secondary Treatment (Chemical)
Chemical Precipitation
In current practice, chemical precipitation is used for the removal of phosphorus and for the
removal of heavy metals.
Common Precipitants:
•Lime
•Ferric Chloride
•Soda Ash
•Ferric Sulfate
•Alum

Chemical Coagulation
An electrochemical process used in the removal of colloidal matter in wastewater through the
addition of coagulating agents which reduce the electrostatic chargers surrounding colloidal
matter.
Common Coagulants:
•Alum
•Copperas

Chemical Flocculation
A physico-chemical process used in the removal of finely divided solids, a polyelectrolyte is
added to wastewater which can form bridges that will join together the solids.
Common Flocculants
•Anionic Polyacrylamide
•Alginates
•Sodium Aluminate
•Sodium Silicate

Tertiary Treatment
Disinfection
refers to the destruction of pathogenic microorganisms for the sole purpose of preventing
transmission of disease through water.
Sterilization
killing of ALL microorganisms present in water

Tertiary Treatment
Chlorination
Chlorine is used to disinfect wastewater in either gaseous form (Cl2), or as hypochlorite salts. All
forms of chlorine react with water to produce hypochlorous acid (HOCl), which rapidly
dissociates to form the hypochlorite ion according to the following reaction:
Cl2 +H2O ↔ HOCl + H+
+Cl-
HOCl ↔ OCl-
+ H+

Tertiary Treatment
Ozonation
Disinfection by ozonation is achieved using the formation of free radicals as oxidizing agents.
Ozonation is more effective against viruses and bacteria than chlorination, yet problems with
effective bactericidal action occur when conditions are not ideal.

Tertiary Treatment
Ultraviolet radiation
A physical process that principally involves passing a film of wastewater within close proximity
of a UV source (lamp). The efficiency of UV disinfection depends on the physical and chemical
water quality characteristics of the wastewater prior to disinfection.

Advanced Treatment Process
Carbon Adsorption
Reverse Osmosis
Micro, Nano and Ultrafiltration;
Electrodialysis
Ion-exchange

Integrated Solid Waste Management
The selection and application of suitable techniques, technologies and management programs
to achieve specific waste management objectives.
Includes factor like: frequency of collection, types of wastes collected, location of disposal site
and environmental acceptability of disposal system and level of satisfaction to customers.

Hierarchy of SWM
Prevention
Reduction
Recycling
Treatment
Dis
pos
al

Hierarchy of SWM
Reduce and Reuse
• Replacing raw materials (e.g. bioplastics-
replacing petroleum based plastics)
•Economic instruments to reduce waste
generation (Polluter pays principle)
Waste minimization
•Consumer behavior and ordinances
•Redesigning manufacturing process to reduce
waste

Hierarchy of SWM
Treatment
•Anaerobic Digestion-biological process that
occurs when organic matter is decomposed by
bacteria in the absence of oxygen. As the
bacteria decompose the organic matter, biogas
is released and captured.
•Biogas consists of approximately 60% methane
and 40% carbon dioxide.
•By-product is called Digestate and is low in
odor and nutritious.

Hierarchy of SWM
Treatment
•Composting-aerobic method of decomposing
organic solid wastes.
•The process involves decomposition of organic
material into a humus-like material, known as
compost, which is a good fertilizer for plants.
•Composting requires the following three
components: human management, aerobic
conditions, development of internal biological
heat.

Hierarchy of SWM
Treatment
•Incineration with energy recovery
•”Banned” in the Philippines.
•May emit dioxins and furans
•Volume reduction of 70%
•Capital intensive and needs constant feedstock

Functional Elements of SWM
Generation
Amount of waste generated depends on the level of economic activity.
Storage
Trash bins/trash cans
Onsite Collection
Must isolate waste from the environment to prevent health hazard.
Collection
Accounts for significant portion of total cost

Functional Elements of SWM
Transfer/Transport
Direct or by transfer stations
Treatment
Recycling, Composting or Incineration
Disposal
Controlled dumpsite/Sanitary Landfill

Landfill Planning Considerations
Required Capacity
Area and volume required for MSW disposal
Depends on: Projected waste generation, rate of population growth, density to which waste is
compacted at landfill
NIMBY (Not in my backyard mentality)
Resident concerns: health and environmental risks, negative impact on aesthetics in the area,
lowering of property values
Hydro-geology
presence of water table, hydrological conductivity of the soil, annual precipitation, degree of
seismic activity in the area

Landfill Components and Configuration

Air Pollution
Alteration of the physical, chemical and biological properties of the atmosphere that is likely to
create harmful effects on public health, safety, and welfare
Different Air Pollutants
COx
CH 4
NO x
VOC
SO X
PM 10

Air Pollutant Classifications
Primary Pollutant
emitted by an identifiable source (e.g. CO,NOx,COx,SOx)
Secondary Pollutant
formed by the chemical reactions of the primary pollutants (e.g. acid rain)
Criteria Pollutant
6 criteria pollutants; CO,Pb,NO2,O3,PM and SO2
Non-criteria Pollutant
other than criteria pollutants

Air Pollution
Mobile sources generated the largest share of carbon monoxide in the metropolis at 99.21%
followed by the total organic gases at 93.5%, NOx at 82.86%, PM10 at 16.36%, SOx at 11.75%
and PM at 10.59% (EMB-DENR, 1999).

Major Air Pollutants
Carbon Dioxide
Main product of fossil fuel combustion; major greenhouse gas when it displaces oxygen in the air
causing suffocation due to binomia.
CO
Product of incomplete combustion; causes anoxicity where CO reacts with hemoglobin forming
carboxyhemoglobin
SOx
Acid rain precursors
NOx
Formed mainly during high temperature combustion of fuel in cars; causes reddish-brown haze in city
air; contributor to the formation of ground level bad ozone (tropospheric ozone)

Major Air Pollutants
Chlorofluorocarbons (CFCs)
Artificial gases used as coolants in refrigerators and air conditioners
Non-toxic, non-flammable, non-biodegradable, non-water soluble
Stable and can reach the stratosphere
Particulate Matter (PM)
Contribute to urban haze, cause visibility reduction

Air Pollution Control Equipment
Settling Chambers
Particulate removal is by gravity; recommended for particulate sizes in the range of 50 microns
or higher.
Cyclone Collector
Dirty gas is fed peripherally into the device. Particulate removal is by centrifugal impaction on
the cyclone wall from where it falls to the bottom; recommended for particulates of 20 to 45
microns in size.
Venturi Scrubbers
Uses water to effect particulate separation from the gas stream; recommended for particulates
of 5 to 20 microns and should have high affinity for water.

Air Pollution Control Equipment
Filters
Separates the particulates from the main stream by direct interception; filter medium is cloth or
acetate membrane filters
Electrostatic Precipitators
Most efficient method; recommended for all sizes if particulates especially those below 1 to 10
microns; gas is given an electrical charge as it enters the device.

Philippine Environmental Laws
RA 6969 – Toxic Substances and Hazardous and Nuclear Wastes Control Act of 1990
RA 8749 – Philippine Clean Air Act of 1999
RA 9003 – Ecological Solid Waste Management Act of 2000
RA 9275 – Philippine Clean Water Act of 2004
PD 1151 – Philippine Environmental Policy
PD 1152 – Philippine Environmental Code

List of International Agreements
Atmosphere
Framework Convention on Climate Change (UNFCC), New York, 1992
Kyoto Protocol, Japan 1997
Vienna Convention for the Protection of the Ozone Layer, Vienna, 1985
Montreal Protocol on Substances the Deplete the Ozone Layer, Montreal, 1987

Hazardous Substances
Convention on the Control of Transboundary Movements of Hazardous Wastes and their
Disposal, Basel, 1989
Convention on the Prior Informed Consent Procedure for Certain Hazardous Chemicals and
Pesticides in International Trade, Rotterdam, 1998
Minamata Convention on Mercury, Minamata 2013
Stockholm Convention Stockholm Convention on Persistent Organic Pollutants Stockholm, 2001

Nature Conservation and Terrestrial Living Resources
Ramsar Convention Convention on Wetlands of International Importance, especially as
Waterfowl Habitat, Ramsar, 1971
Nuclear Safety
Comprehensive Test Ban Treaty 1996
Convention on Early Notification of a Nuclear Accident (Notification Convention), Vienna, 1986

Introduction to Environmental Engineering.pptx

More Related Content

Similar to Introduction to Environmental Engineering.pptx

Recently uploaded

Introduction to Environmental Engineering.pptx