Water pollution is any change in water quality that harms living organisms or makes water unsuitable for use. It causes over 14,000 daily deaths worldwide. Pollution can come from natural sources like volcanoes or human sources like factories and cities. Increased nutrients cause eutrophication and hypoxia, reducing oxygen levels and harming marine life. Many pollutants accumulate up the food chain. Water quality is measured through tests of bacteria, oxygen levels, and chemical concentrations. Proper management is needed to address this global public health and environmental issue.
We can work together to keep the environment clean so the plants, animals and people who depend on it remain healthy :) Working together, we can make pollution less of a problem and make our world a better place :D :)
water pollution control and measurmentRekha Kumari
Today we all are facing the biggest problem that is scarcity of drinking water as the level of water is continually decreasing.
In many countries people die because of contaminated water as they do not have any water resources that contain pure water.
The first question comes in mind when we talk about water management is how can we manage water. For this we need some well-planned strategies like if we know the places where heavy rainfall occur, then we can put extra efforts there in order to save water for future use.
We can work together to keep the environment clean so the plants, animals and people who depend on it remain healthy :) Working together, we can make pollution less of a problem and make our world a better place :D :)
water pollution control and measurmentRekha Kumari
Today we all are facing the biggest problem that is scarcity of drinking water as the level of water is continually decreasing.
In many countries people die because of contaminated water as they do not have any water resources that contain pure water.
The first question comes in mind when we talk about water management is how can we manage water. For this we need some well-planned strategies like if we know the places where heavy rainfall occur, then we can put extra efforts there in order to save water for future use.
This PPT contains definition, types, signs, source and effects of water pollution. Prevention of water pollution and some data of water pollution of world. It contains pictures so high school grade student can also go through this PPT. Although It is for Bachelor's level.
Water has its own taste, color, smell and constituents. Not all water can be used for all purposes. Eg. Sea water can not be used by us for drinking. The suitability of water for different purposes is determined by its quality parameters. The Quality of water is equally important than quantity. Even if present in huge amounts, we can not use salt water in many life support activities. Water has its own Physical properties, Chemical composition and Biological Properties. This module highlights the water quality parameters that are essential.
Here you will find brief description about water sampling. actually it's so important to examine the water we use our daily life in order to avoid negative impact of water.
This PPT contains definition, types, signs, source and effects of water pollution. Prevention of water pollution and some data of water pollution of world. It contains pictures so high school grade student can also go through this PPT. Although It is for Bachelor's level.
Water has its own taste, color, smell and constituents. Not all water can be used for all purposes. Eg. Sea water can not be used by us for drinking. The suitability of water for different purposes is determined by its quality parameters. The Quality of water is equally important than quantity. Even if present in huge amounts, we can not use salt water in many life support activities. Water has its own Physical properties, Chemical composition and Biological Properties. This module highlights the water quality parameters that are essential.
Here you will find brief description about water sampling. actually it's so important to examine the water we use our daily life in order to avoid negative impact of water.
info about refuse chute for hospital area.....all standard sizes and dimention are mentioned in it....so it will be heplfull for you to design refuse chute in Hospital
A TEXT BOOK : Complete and comprehensive inputs in Learning about Biogas and Biogas digestors:We have tried to take the mystery away from biogas.
Biogas is a renewable energy source with many different production pathways and various excellent opportunities to use.
One main advantage of biogas is the waste reduction potential. Biogas production by anaerobic digestion is popular for treating biodegradable waste because valuable fuel can be produced while destroying disease-causing pathogens and reducing the volume of disposed waste products.
Biogas burns more cleanly than coal, and emits less carbon dioxide per unit of energy. The carbon in biogas was recently extracted from the atmosphere by photosynthetic plants. Releasing it back into the atmosphere adds less total atmospheric carbon than burning fossil fuels.
Thus, biogas production kills two birds with one stone: it reduces waste and produces energy. In addition, the residues from the digestation process can be used as high quality fertilizer. This closes the nutrient cycle.
Water pollution is an appalling problem, powerful enough to lead the world on a path of destruction. Water is an easy solvent, enabling most pollutants to dissolve in it easily and contaminate it. The most basic effect of water pollution is directly suffered by the organisms and vegetation that survive in water, including amphibians. On a human level, several people die each day due to consumption of polluted and infected water.
Darshit gajjar(Software eng)
This water pollution but I don't like environment .but I make ppt bacuase our sar punish me.so that all guys watch my ppt my ppt is best for other.i am software eng .so that I make my ppt of IT realeted so that watch my environment ppt
Marine pollution is the introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries), resulting in such deleterious effects as: harm to living resources; hazards to human health; hindrance to marine activities including fishing; impairing the quality for use of sea water and reduction of amenities
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Instructions for Submissions thorugh G- Classroom.pptx
Water pollution and treatment PPT
1.
2. Water Pollution
Water pollution is any chemical, biological, or physical change in
water quality that has a harmful effect on living organism or makes
water unsuitable for desired uses.
It has been suggested that it is the leading worldwide cause of
deaths and diseases, and that it accounts for the deaths of more
than 14,000 people daily.
3. Human and Natural Pollutants
Water is typically referred to as polluted when it is
impaired by anthropogenic contaminants.
Natural phenomena such as volcanoes, alga
blooms, storms, and earthquakes also cause majo
changes in water quality.
4. Sources of Water Pollution
NONPOINT
SOURCES
Rural homes
Urban streets Cropland
Animal feedlot
Suburban POINT
development SOURCES
Factory
Wastewater
treatment
plant
5.
6. Eutrophication
An increase in chemical nutrients —
compounds containing nitrogen or phosphorus
— in an ecosystem, and may occur on land
or in water. However, the term is often used
to mean the resultant increase in the
ecosystem's primary productivity (excessive
plant growth and decay), and further effects
including lack of oxygen and severe Eutrophication of the Potomac River.
reductions in water quality, fish, and other
animal populations.
7. Hypoxia
A phenomenon that occurs in aquatic
environments as dissolved oxygen
( DO ; molecular oxygen dissolved in
the water) becomes reduced in
concentration to a point detrimental
to aquatic organisms living in the
system.
Oxygen depletion can be the result
of a number of factors including
natural ones, but is of most concern
as a consequence of pollution and
eutrophication in which plant nutrients
enter a river, lake, or ocean,
phytoplankton blooms are
encouraged.
8. Industry Cities Urban sprawl Construction sites
Nitrogen oxides from autos Toxic metals and Bacteria and Sediments are washed into waterways,
and smokestacks; toxic oil from streets and viruses from sewers choking fish and plants, clouding
chemicals, and heavy parking lots pollute and septic tanks waters, and blocking sunlight.
metals in effluents flow waters; sewage contaminate shellfish
into bays and estuaries. adds nitrogen and beds and close Farms
phosphorus. beaches; runoff Run off of pesticides, manure, and
of fertilization from fertilizers adds toxins and excess
lawns adds nitrogen nitrogen and phosphorus.
and phosphorus.
Red tides
Excess nitrogen causes explosive
Closed
shellfish beds growth of toxic microscopic algae,
Closed poisoning fish and marine mammals.
beach Oxygen-depleted
zone
Toxic sediments
Chemicals and toxic metals
contaminate shellfish beds,
kill spawning fish, and
accumulate in the tissues
of bottom feeders.
Healthy zone
Clear, oxygen-rich waters
Oxygen-depleted zone promote growth of plankton
Sedimentation and algae and sea grasses, and support fish.
overgrowth reduce sunlight,
kill beneficial sea grasses,
use up oxygen, and degrade habitat.
9. Marine Pollution
Entry into the ocean of chemicals, particles,
industrial, agricultural and residential waste,
or the spread of invasive organisms.
Most sources of marine pollution are land
based. The pollution often comes from
nonpoint sources such as agricultural runoff
and wind blown debris.
Many potentially toxic chemicals adhere to
tiny particles which are then taken up by
plankton and benthos animals, most of which
are either deposit or filter feeders.
Toxins are concentrated upward
(biomagnification) within ocean food chains.
10. Marine Debris
Human-created waste that has
deliberately or accidentally become
afloat in a lake, sea, ocean or
waterway. Oceanic debris tends to
accumulate at the centre of gyres
and on coastlines, frequently washing
aground, when it is known as beach
litter.
Plastic bags, balloons, buoys, rope,
medical waste, glass bottles and
plastic bottles, cigarette lighters,
beverage cans, styrofoam, lost fishing
line and nets, and various wastes from
cruise ships and oil rigs are among
the items commonly found.
11. Ocean Acidification
The ongoing decrease in the pH of the
Earth's oceans, caused by their uptake of
anthropogenic carbon dioxide from the
atmosphere.
Human activities such as land-use changes,
the combustion of fossil fuels, and the
production of cement have led to a new flux
of CO 2 into the atmosphere.
Dissolving CO2 in seawater also increases
the hydrogen ion (H + ) concentration in in sea surface pH caused by
the
Change
ocean, and thus decreases ocean pH. anthropogenic CO2 between the 1700s
and the 1990s.
12. Ship Pollution
Spills from oil tankers and chemical
tankers
Ejection of sulfur dioxide, nitrogen
dioxide and carbon dioxide gases into
the atmosphere from exhaust fumes.
Discharge of cargo residues from bulk
carriers can pollute ports, waterways
and oceans.
Noise pollution that disturbs natural
wildlife.
Water from ballast tanks can spread
harmful algae and other invasive
species.
13. Thermal Pollution
The rise or fall in the temperature of a
natural body of water caused by human
influence.
A common cause is the use of water as a
coolant by power plants and industrial
manufacturers.
Warm water typically decreases the level
of dissolved oxygen in the water . The
decrease in levels of DO can harm
aquatic animals.
May also increase the metabolic rate of
aquatic animals, as enzyme activity,
resulting in these organisms consuming
more food.
14. Surface Runoff
Surface runoff can be generated either by
rainfall or by the melting of snow or
glaciers.
It is the water flow which occurs when soil
is infiltrated to full capacity and excess
water, from rain, snowmelt, or other
sources flows over the land. This is a major
component of the water cycle.
When runoff flows along the ground, it can
pick up soil contaminants such as
petroleum, pesticides (in particular
herbicides and insecticides), or fertilizers
that become discharge or nonpoint source
pollution.
Runoff flowing into a
stormwater drain.
15. Urbanization and Surface Run Off
Urbanization increases surface runoff,
by creating more impervious surfaces
such as pavement and buildings, that
do not allow percolation of the water
down through the soil to the aquifer. It
is instead forced directly into streams
or storm water runoff drains, where
erosion and siltation can be major
problems, even when flooding is not.
Increased runoff reduces groundwater
recharge, thus lowering the water table
and making droughts worse, especially
for farmers and others who depend on
water wells.
16. Water Stagnation
Occurs when water stops flowing.
Malaria and dengue are among the
main dangers of stagnant water,
which can become a breeding
ground for the mosquitoes that
transmit these diseases.
21. Waste Water
Comprises liquid waste discharged
by domestic residences, commercial
properties, industry, and/or
agriculture and can encompass a
wide range of potential
contaminants and concentrations.
24. Turbidity
The cloudiness or haziness of a fluid caused by
individual particles (total suspended solids - TSS) that
are generally invisible to the naked eye, similar to
smoke in air.
Turbidity in open water may be caused by growth of
phytoplankton.
Human activities that disturb land, such as construction,
can lead to high sediment levels entering water bodies
during rain storms, due to storm water runoff, and
create turbid conditions.
Turbidity standards of
Urbanized areas contribute large amounts of turbidity 5, 50, and 500 NTU
to nearby waters, through stormwater pollution from
paved surfaces such as roads, bridges and parking lots.
Industries such as quarrying, mining and coal recovery
can generate very high levels of turbidity from colloidal
rock particles.
25. Measuring Turbidity
A nephelometer is an instrument for measuring
suspended particulates in a liquid or gas colloid. It
does so by employing a light beam (source beam)
and a light detector set to one side (usually 90 ) of
the source beam. Particle density is then a function
of the light reflected into the detector from the
particles.
A nephelometric turbidimeter always monitors light
reflected off the particles and not attenuation due
to cloudiness.
In the United States environmental monitoring the
turbidity standard unit is called Nephelometric
Turbidity Units (NTU ), while the international
standard unit is called Formazin Nephelometric Unit
( FNU ).
A nephelometer at the Kosan, Cheju
Island, South Korea NOAA facility.
26. Secchi Disks
Turbidity in lakes, reservoirs, and the ocean can be
measured using a Secchi disk. This black and white disk is
lowered into the water until it can no longer be seen; the
depth (Secchi depth) is then recorded as a measure of the
transparency of the water (inversely related to turbidity).
The Secchi depth is reached when the reflectance equals
the intensity of light backscattered from the water.
The Secchi disk has the advantages of integrating turbidity
over depth (where variable turbidity layers are present),
being quick and easy to use, and inexpensive. It can
provide a rough indication of the depth of the euphotic
zone with a 3-fold division of the Secchi depth .
Limitations: Secchi disk readings do not provide an exact
measure of transparency, as there can be errors due to the
sun's glare on the water, or one person may see the disk at
one depth, but another, with better eyesight, may see it at
a greater depth.
27. Biochemical Oxygen Demand (BOD)
A chemical procedure for determining how fast
biological organisms use up oxygen in a body of
water.
BOD can be used as a gauge of the effectiveness of
wastewater treatment plants.
The BOD test is carried out by:
1. diluting the sample (sludge) with oxygen saturated de-
ionized water,
2. inoculating it with a fixed aliquot of seed, measuring the
dissolved oxygen (DO) and then sealing the sample to prevent
further oxygen dissolving in.
3. sample is kept at 20 C in the dark to prevent
photosynthesis (and thereby the addition of oxygen) for five
days, and the dissolved oxygen is measured again.
4. difference between the final DO and initial DO is the BOD.
28. Common Levels of BOD:
Most pristine rivers below - 1 mg/L.
Moderately polluted rivers - in the range of 2 to 8
mg/L.
Municipal sewage that is efficiently treated by a
three-stage process would have a value of about
20 mg/L or less.
Untreated sewage varies, but averages around 60
mg/L.
29. Fecal Coliforms
Are facultatively-anaerobic, rod-shaped, gram-
negative, non-sporulating bacteria.
Include the genera that originate in feces; Escherichia
as well as genera that are not of fecal origin;
Enterobacter, Klebsiella, and Citrobacter.
Increased levels of fecal coliforms (fecal bacteria)
provide a warning of failure in water treatment, a
break in the integrity of the distribution system, or
possible contamination with pathogens.
Fecal coliform bacteria can enter rivers through
direct discharge of waste from mammals and birds,
from agricultural and storm runoff, and from
untreated human sewage. However their presence
may also be the result of plant material, and pulp or
paper mill effluent.
The assay is intended to be an indicator of fecal A fecal coliform plate
contamination, or more specifically E. coli which is an
indicator microorganism for other pathogens that
may be present in feces.
EPA acceptable Levels is 0 colonies.
30. Qualitative Water Tests
Habitat Evaluation Index
(e.g., substrate analysis, in-stream cover, chann
morphology, raparian zone and bank erosion,
gradient) -
http://rock.geo.csuohio.edu/norp/qhei.htm
Biodiversity Index . the different numbers an
types of species,
(e.g., macroinvertebrates, bacteria, algae,
amphibians, fish,plants).
32. Indicator Species
Any biological species that defines a
trait or characteristic of the
environment.
Species may delineate an ecoregion or
indicate an environmental condition such
as a disease outbreak, pollution, species
competition or climate change.
Can be among the most sensitive
The American Dipper is a bird
species in a region, and sometimes act that requires a habitat of clear,
as an early warning to monitoring mountainous streams, and can
biologists. be displaced by siltation from
land development, land-wasting
runoff and forest fire runoff.
33. Range of Tollerance
Clean Zone Decomposition Septic Zone Recovery Zone Clean Zone
Zone
Normal clean water organisms Trash fish Fish absent, fungi, Trash fish Normal clean water organisms
(trout, perch, bass, (carp, gar, sludge worms, (carp, gar, (trout, perch, bass,
mayfly, stonefly) leeches) bacteria leeches) mayfly, stonefly)
(anaerobic)
8 ppm 8 ppm
Dissolved oxygen
Oxygen sag
Biological oxygen 2 ppm
demand
Direction of flow
Point of waste or
heat discharge
Time or distance downstream
35. Amphibians
Include frogs, toads,
salamanders, newts, and
gymnophiona, and are cold-
blooded animals that
metamorphose from a juvenile,
water-breathing form to an
adult, air-breathing form.
Are indicator species of
ecological conditions relating
to global warming, air
pollution chemicals, stormwater
runoff, and newly extant
diseases (e.g. fungus).
36. Frogs
http://www.hcn.org/issues/60/1859
Farm fertilizers. These
chemicals boost algae
production which in turn boost
the population of certain
flatworm parasites. These
parasite attack frogs at their
larval stage (tadpoles),
causing them to develop
deformities in adulthood.
Deformities include missing or
extra limbs.
37. Sources of Eutrophication
Discharge of untreated
municipal sewage
Nitrogen compounds
(nitrates and phosphates) produced by cars
and factories
Natural runoff
(nitrates and
phosphates
Inorganic fertilizer runoff
Discharge of (nitrates and phosphates)
detergents
( phosphates)
Manure runoff
from feedlots
Discharge of treated (nitrates,
municipal sewage phosphates,
(primary and secondary ammonia)
treatment:
nitrates and phosphates) Runoff from streets,
lawns, and construction
Lake ecosystem
lots (nitrates and
nutrient overload
phosphates)
and breakdown of
chemical cycling
Dissolving of Runoff and erosion
nitrogen oxides (from cultivation,
(from internal combustion mining, construction,
engines and furnaces) and poor land use)
38. Effects of Natural and Cultural Eutrophication
Excessive amounts of algae can deplete dissolve
oxygen content in the lake
It can also cause bacteria to take over and
produce toxic levels of hydrogen sulfide and
flammable methane
39. Reduction Methods
Use advanced waste treatment to remove nitrate
and phosphates
Bans or limits on phosphates in household
detergents and other cleaning agents
Soil conservation and land-use control to reduce
nutrient runoff
40. Climate Change and Water Pollution
Global warming changes patters of precipitation, such as
flooding and drought.
Flooding can cause an increase of disease-carrying
pathogens, or the overflow of human and animal wastes
from sewer lines.
Drought can cause reduced river flows that dilute wastes
increase salinity levels, and cause infectious disease to
spread more rapidly because people lack enough water
to stay clean.
47. Safe Drinking Water
Is water that is of sufficiently high
quality so that it can be consumed or
utilized without risk of immediate or
long term harm, such water is
commonly called potable water.
95% in (more developed countries)
MDC’s have safe drinking water
74% in (less developed countries)
LDC’s have safe drinking water
48. Human Requirements
2 to 3 liters of water for
men
1 to 2 liters of water for
women should be taken
in as fluid
RDI - Reference Daily
Intake
51. WHO Report on Drinking Water
http://www.who.int/water_sanitation_health/monitoring/jmp2006/en/
1.4 billion people do not
have safe drinking water
9,300 die daily from
water-borne diseases
Cost of $23 billion to bring
safe drinking water and
sanitation to everyone over
8-10 years.
53. Key Points of Clean Water Act
regulate the discharge of pollutants into U.S. waterways
attain water quality levels that make these waterways safe to
fish and/or swim in
restore and maintain the chemical, physical, and biological
integrity of the nations water
set water quality standards to limit pollutants
require states and tribes to complete an assessment of all st
rivers impacted, or
potentially impacted, by non-point pollution (Section 319)
reduce polluted runoff from urban areas and animal feeding
operations (Section 319)
provide enforcement mechanisms (e.g. civil actions/criminal
penalties) to ensure
57. Water Purification
The process of removing undesirable chemical and
biological contaminants from raw water.
Designed to meet drinking, medical, pharmacology
chemical and industrial applications.
Treatment processes also lead to the presence of
some mineral nutrients: fluoride, calcium, zinc,
manganese, phosphate, and sodium compounds.
62. Tertiary Treatment
Effluent from Alum Specialized
secondary flocculation Desalination compound
Activated (electrodialysis Nitrate
treatment plus sediments removal
carbonor reverse osmosis)removal
(DDT, etc.)
98% of To rivers, lakes,
suspended solids streams, oceans,
90% of reservoirs, or industries
phosphates
98% of Most of
dissolved dissolved salts
organics
Recycled to land
for irrigation
and fertilization
63. Wetland Addition
(1) Raw sewage drains by (3) Wastewater flows through
gravity into the first pool another perforated pipe
and flows through a long into a second pool, where
perforated PVC pipe into the same process is repeated.
a bed of limestone gravel.
Sewage Treated
water
Wetland type Wetland type
plants plants
45 centimeter
layer of limestone
gravel coated with
First concrete pool decomposing bacteria Second concrete pool
(2) Microbes in the limestone gravel (4) Treated water flowing from the
break down the sewage into second pool is nearly free of
chemicals that can be absorbed bacteria and plant nutrients.
by the plant roots, and the gravel Treated water can be recycled
absorbs phosphorus. for irrigation and flushing toilets.