This document discusses emerging and re-emerging challenges in water quality. It outlines key water quality parameters and indicators, including physiochemical factors and bio-indicators like E. coli. Emerging challenges include polluted runoff transporting pathogens, combined sewer overflows during storms, and rapid urbanization overwhelming sanitation systems. Re-emerging pathogens are also discussed, driven by new environments, technologies, and intensive livestock practices. Recommendations focus on improved sanitation, integrated water management, wastewater treatment, and monitoring to address these challenges.

1. Page 1
EMERGING AND RE-EMERGING
CHALLENGES IN WATER
QUALITY
GAQAVU SISIPHO
ADELABU OLUSESAN
SEPTEMBER DOLLY

2. Page 2
OUT-LINE
• Water quality
• Physiochemical parameters that influence water
quality
• Water quality indicators
• Emerging and Re-emerging challenges in water
quality
• Potential drivers of emerging and re-emerging
pathogens in water
• Recommendations

3. Page 3
Introduction
• Water quality- the chemical, physical and biological
characteristics of water that measure the condition
of water relative to the requirements of one or more
biotic species and or to any human need or purpose
• Emerging challenges-are those challenges that have
appeared for the first time, or have occurred
previously but are increasing in incidence or
expanding into areas where they have not previously
been reported
• Re-emerging challenges- are those challenges that
emerge again; come into sight once more.

4. Physiochemical Parameters

5. Page 5
Water quality Indicators
• Turbidity
• pH
• dissolved oxygen
• temperature
• nitrates
• bio-indicators

6. Page 6
Bio-indicators
• Faecal Coliforms are naturally occurring bacteria
found in the intestines of all warm blooded
animals (including humans) and birds. The
presence of Faecal Coliforms is an indicator of
contamination by sewage waste.
• They are not pathogenic (disease causing) but
indicate that pathogenic bacterial and viruses
may be present

7. Page 7
Bio-Indicators
• Escherichia coli(E. coli) is the major species in
the faecal coliform group
• It is considered the best indicator of faecal
pollution and the possible presence of
pathogens such as (E.coli 0157:H7, Shigella),
and viruses (Rotavirus, Hepatitis E virus),
Protozoa (Giardia, Cryptosporidium)
• Cyanobacteria/ blue-green algae float on the
surface and are associated with water quality
problems

8. Page 8
Pathogens
E.coli 0157H:7 Shigella
Cryptosporangium Giardia
Rotavirus

9. Page 9
Emerging and Re-emerging challenges
• Polluted water run-off
Faecal material as well as other pollutants can
be transported to waterways through runoff.
How quickly they are transported partially
depend on the type of land use
Lands that support domesticated animals,
such as cattle, dogs, or horses, can also be a
source of bacteria, particularly if animals
enter the water for drinking or if heavy rain
washes manure from the land into receiving
waters.

10. Page 10

11. Page 11
Challenges
• Combined sewer overflow
Some sewer and storm water pipes are not
separated, when a large storm event occurs,
the waste water treatment plants cannot
handle the excess volume of water being
pumped to them. As a result, untreated
sewage along with storm water is dumped
directly into rivers and streams

12. Page 12
Combined sewer over flow

13. • Rapid Urbanization
 Is caused by rapid population growth which brings about poor
sanitation, also increases the number of urban dwellers
practising open defecation, e.g. in most low-middle income
countries, open defecation increased from 140 million in 1990
to 169 million in 2008 (Chiramba,2010)
 In most developing countries wastewater is discharged
directly into the sea or rivers without treatment.
Many large cities do not have treatment plants or plants
quickly become undersized as urban population growth
outpaces investments.
Discharge of untreated wastewater shifts problems to
downstream areas

14. Page 14
• Pipeline contamination
Despite the treatment of water sources and use of
chlorine as a disinfectant, contamination of piped
water supply continues to occur, without
necessarily causing large easy to recognise out-
breaks, through leaks or other vulnerable parts of
the pipe system, and during maintenance work
Bacteria, fungi, and protozoa can attach to the
inner surfaces of the pipes and some may grow to
produce biofilms which have been seen to contain
one or more species of pathogens

15. Page 15
Pipeline contamination

16. Page 16
Waterborne pathogens
• Pathogens are disease causing
microorganisms that can create health risks.
• They can be introduced into estuaries from
inadequately treated sewage, runoff from
urban areas, combined sewer overflows and
waste from pets and wildlife
• They pose a health threat to human activities.

17. Page 17
Waterborne pathogens
• Emerging pathogens- are those that have appeared
in a human population for the first time, or have
occurred previously but are increasing in incidence
or expanding into areas where they have not
previously been reported
• Re-emerging pathogens are those whose incidence
is increasing as a result of long-term changes in
their underlying epidemiology

18. Page 18

19. Page 19
New environment

20. Page 20
New environment
• Adaptations by one partner to exploit new
environments will often stimulate the other to
modify its characteristics to take advantage of
the change.
• As a consequence of this cycle of interaction
created by changing environments, new
strains of pathogen will evolve.
• Over time, these strains may emerge as new
species with characteristic disease symptoms.

21. Page 21
New technology
• Many of these technologies will have
significant benefits, but unforeseen problems
with a few may introduce new risks, such as
harmful by-products or pathways of
transmission that may lead to the re-
emergence of water-related pathogens.
• In the context of new technologies, water
distribution systems show how an engineering
solution to one problem can create new
opportunities for contact between humans
and water-related pathogens.

22. Page 22
New technology
• Zoonotic pathogens (Cryptosporidium, E.coli
O157 and Campylobacter) are an example of
emerging and re-emerging pathogens that
result/emerge due to intensive livestock farming
which frequently result in the discharge of
pathogens into water from concentrated animal
wastes and animal feeding operations.
• This shows how a substantial improvement of a
long-term practice can impact watercourses in
ways that are not anticipated

23. Page 23
Recommendations
• Good sanitation practises
- community awareness, educating people on the re-
emergence of these challenges
• Integrated and sustainable water management system
• Improved engineered system by creating separate
pipes for sewage and storm water
• Avoid cross contamination during repair or
maintenance work of pipelines
• Increase in periodic treatment of water so as to
combat the re-emegence of pathogens
• Well managed waste water treatment plants
• General guidelines on irrigation water quality should
be applied to avoid immediate, short and long term
detrimental effects on the environment

24. Page 24
Recommendations
• Monitoring of ground and surface water
resources close to the wastewater area should
be carried out regularly to provide early
warning of pollution status and risk
• Promote the use of wastewater in agriculture
as an alternative to discharge surface waters
will decrease the potential for eutrophication
of surface waters
• Promotion of treatment procedures for waste
purification which are cost effective and
environmentally friendly