this ppt is about waste water condition,common applied strategies and duck weed technology is taken for case study

1. Wastewater Situation, Applied
Strategies & Wastewater management -
Bangladesh
Presented By,
Prantor Kumar Mondal

2. Introduction

3. People’s Republic of Bangladesh
领域(area)：1，47，570 sq-km
人口(population)：160 Millions
文 ：孟加拉语
城池：7个
首都(capital)：达卡 (DHAKA)
金钱(currency)：Taka

4. 孟加拉国的
地图

5. Water pollution
• Bangladesh has about 230 small and large
rivers and a large chunk of the country’s
140million people depend on them for a living
and for transportation. But experts say many
of them are drying up or are choked because
of pollution and encroachment.

6. Standards of Water & Waste water
In Bangladesh

7. Household Drinking Water Quality

9. Ground Water Situation
The Dhaka Water Supply and Sewerage Authority relies on
the treatment of surface water sources to complement
groundwater supplies. However, during the dry season,
river water can become so polluted that it cannot be
effectively treated to drinking water standards. If the
situation worsens, the Dhaka Water Supply and Sewerage
Authority may have to obtain water from the Padma and
Meghna Rivers, with estimated investment costs of
$430million and $285 million, respectively(IWM 2007);

10. The groundwater situation in
Dhaka is particularly
critical .Although reliable
data is hard to obtain (as most
groundwater abstraction is
carried out through unmetered
self-supply), initial calculations
suggest that the textile mills in
and around Dhaka may consume
as much groundwater as is
supplied to the entire megacity
of over 12 million inhabitants

11. Water Pollution

12. Water
Pollution
Point source
Industrial
effluent
Textile Tannery Dyeing Thermal
Municipal
waste
Non-point
source
Agricultural
runoff
Atmospheric

13. Situation of Waste water in
Bangladesh

14. Bangladesh’s economy has benefited from the growth of
its garment sector, but the country faces considerable
challenges managing industrial standards

15. Impact of Water Pollution
Major urban and industrial areas over the past few years have shown
increased evidence of the degradation of both groundwater and surface
water quality.
A pollution assessment carried out by IWM (2007) found that industrial
sources, notably the textile industry, tanneries, and the pharmaceutical
industry, were the largest contributors to pollution in the Dhaka
watershed.
Over 1.3 million cubic meters of heavily polluted industrial wastewater
entered the drainage and river system without treatment on a daily basis
in Dhaka alone. There is also evidence of heavy metals and dissolved solids
in shallow aquifers, while surface water bodies (such as rivers, canals, and
ponds) have low oxygen levels due to domestic sewage and chemical
residues from industry. Most surface water is unfit for human use and is
likely to be dangerous for livestock. The environmental, health, and
economic costs associated with pollution from untreated industrial
effluent are significant.

17. Major
Types
Municipal
Wastewater
Ground Water
Contamination
Oil Spills or
Leakage
Salinity
Intrusion
Agricultural Pesticides
Wastewater
Industrial
Wastewater
Results:
Surface Water Source: Pond, Lake, Wetland, Stream, Channel, River and Sea.
Ground Water Source: Water Table, Deep Tube-well, Dug well, and Shallow Pump.

18. Industrial Effluent Discharge
• Numerous textile and tannery industries in Bangladesh
• Required to have ETP
• Expensive to treat effluent
• Owners reluctant to spend money on non-productive issues
such as ETP
• Engineers tend to compromise with the owners
• Technology to treat textile dye may not always be
economically viable
• Buyers and consumers expect good governance &
implementation of rules
• Enforcement of regulations inadequate in the past; at present
more strictly enforced

19. Water pollution sources and their
Ranking

20. Standards for Textile Industry

21. Waste materials dumping in Turag RiverSewage discharge in Bonshi River

22. Sewage discharge in Balu riverIndustrial wastewater discharge in
Turag river

23. Polluted waste water

24. Hatirjheel
Sewage outfall

25. Thermal Plume Discharge in Sitalakhhya River
Haripur Barge-Mounted Power Plant CDC Globeleque Power Plant
Shiddhirgonj Power Plant Outfall

26. Sludge Cake
Dysfunctional ETP

27. Arsenic pollution in Bangladesh
• For the past two decades the water from over a
million tubes has been slowly poisoning Bangladeshi
villagers with naturally occurring arsenic. Over 18
millions people are drinking this poisoned water daily

28. Arsenic affected people

32. Sewerage system
• Mixed provision:
noted by Hawkins et al. (2013) many towns and cities, especially in
developing countries, have a mix- ture of on- and off-site sanitation
facilities and ser- vices. These may be provided by householders, by
developers or by the municipality or utility. The poor sanitary
conditions experienced in many towns and cities around the world
and the problems relating to badly managed and inadequate on-site
and off-site sanitation systems can be illustrated using a faecal
waste flow diagram (developed by Peal et al., in press a/b), which
illustrates the different pathways that faecal waste takes along the
sanitation ser- vice chain. Figure 3, illustrates the problems seen in
Dhaka in Bangladesh, where 20% of faecal waste is sewered and
79% goes to on-site containment.

33. Width of the bars represents
the proportion of faecal waste
at each step in the chain;
orange shading represents
unsafe management; green
shading represents effective
management

35. De-centralised domestic wastewater and faecal sludge
management in Bangladesh
• Inspired by the success of a technology called Vacutug
developed in Kenya , Water Aid imported a Vacutug system to
pilot in Dhaka. Based at Sanitation Programme in Mirpur,
started the pilot phase in December 2000 to test the use of
Vacutug in the Bauniaband slum.

36. The Vacutug being used to
desludge a cesspool

37. Comparative picture of the Vacutug and traditional
services Vacutug service Traditional sweeper’s service

38. Bangladesh Export Processing Zone

39. Central or Common: Effluent
Treatment plant at Savar
Individual: ETP, Hossain
Dyeing, Tongi

41. Pagla Sewage Treatment
Plant in Dhaka

42. Waste water treatment plant Dhaka
Video

43. Water Treatment Technologies in
Bangladesh

44. Applied Water Treatment Technologies in Bangladesh:
Arsenic Removal
 Safi Filter (laterite soil),
 Tin Kolsi Method (Sand, gravel, pebble),
 Oxidation,
 Coagulation, precipitation and filtration,
 Adsorption (sorptive filtration),
 Ion exchange, and
 Membrane techniques.
Iron Removal
 Tin Kolsi Method, and
 Well Water Iron Filters
Industrial Effluent and
Municipal Wastewater
 Physical Process,
 Chemical Process, and
 Biological Process

45. Oil Removal
Drinking Water
 Powdered chemicals spray from a vessel to
subside the oil to protect oxygen reduction
 Fishing nets to sweep away oil
 Traditional methods of neutralising oil and
 New technology based on local ones
 Adsorption,
 Co-precipitation, and
 Reverse Osmosis (RO) Method.
Desalinisation
 Reverse Osmosis (RO) Method ,
 Solar Desalinisation,
 Multi-Stage-Flash (MSF),
 Multieffect-Distillation (ME) with Thermal
 Vapour Compression (ME-TVC) and
There are also some technologies for rural area and new modern technologies

46. Wastewater Treatment Using
Duckweed

47. Wastewater Treatment Using
Duckweed
• Technical Description
This is a relatively new technology in which
small-scale wastewater treatment can be
achieved using duckweed (Lemna spp. or
Spirodela sp.). Duckweed is a self growing
plant abundant in the tropical countries. It is
commonly used as a fertilizer in paddy fields,
but has recently been used in the treatment of
wastewater in Bangladesh. In Mirzapur,
Bangladesh.

48. Duckweed Ponds

50. Low-cost pour-flush latrine. Excreta is collected and
digested in the submerged bamboo case placed directly in
the duckweed pond releasing nutrients through diffusion

51. Family/village level pour-flush pit latrine. Settle able solids sink to the
bottom of the water-sealed pit where they undergo anaerobic decomposition. The
liquid effluent overflows from the pit into the adjacent duckweed pond, while sludge
remains at the bottom of the pit from where it has to be removed periodically
(Edwards et al. 1987

52. Wastewater Treatment Using
Duckweed
• Operation and Maintenance
Use of this technology is simple, being based upon a modification of
conventional maturation lagoon technology.
• Level of Involvement
This technology can be implemented at either the individual farm or
community levels.
• Costs
costs are estimated to be low.
• Effectiveness of the Technology
Since 1989, PRISM, Bangladesh, has developed farming systems
using duckweed-based technology and tested their potential for
wastewater treatment and fish food.
• Suitability
This technology is suitable in tropical climates

53. Different duckweed treatment systems depending on
type and amount
of wastewater.

54. Pond Design
• Two basic principles for pond design and
operation are Used for duckweed treatment. Namely
1. plug-flow
2. batch systems.
Plug-flow design is suitable for treatment of large and
regular wastewater flows originating from communities
and peri-urban areas.

55. Duckweed-covered serpentine plug-flow lagoon in the USA
for tertiary treatment of effluent from three facultative lagoons followed by a
wetland buffer. Design flow is reported at 19,000 m3/d, with peak flows
reaching 38,000 m3/d. (Photograph: Lemna Corp. 1994).

56. Duckweed can be used for combined wastewater treatment and
production of high protein biomass up to the point where
nutrient limitation diverges the two so far parallel running
processes.
To achieve optimum treatment efficiency and protein
production, an ideal plug-flow design should include multiple
wastewater inlet points and allow recirculation of the final
effluent.

57. Ideal plug-flow system for combined duckweed-based
wastewater
treatment and protein production

58. Batch-operated ponds are a feasible option for
introduction of duckweed aquaculture in villages where
already existing ponds can often be used and, thus, save
capital costs for extra earth work. In comparison with a
continuous flow through system, duckweed growth may
be enhanced near the nutrient inlet points as a result of
reduced nutrient mixing and distribution.
A narrow pond design allowing duckweed harvesting
from the embankment is also favored here.

59. Batch-operated pond for duckweed cultivation at village
level showing dense duckweed cover and pour-flush latrine
influent for nutrient supply in the background (Bangladesh).

60. Water Depth
The critical factor with respect to water depth is to ensure vertical
mixing in the pond to allow the wastewater to be treated to come
into contact with the duckweed fronds for nutrient uptake and BOD
degradation through attached microbial populations. An outlet
structure is recommended in order to vary the operating depth
(Metcalf and Eddy 1991).
Reported pond depths range from 0.3 to 2.7 m up to even 5 m
(Lemna Corp. 1994). The majority of authors report an optimal
depth ranging from 0.4 to 0.9 m, implying that a maximum depth of
one meter is sufficient for acceptable temperature buffering. Higher
depths are also a feasible option for systems with relatively low
BOD loads, a low recirculation rate and high land costs. Shallow
system depths are, however, better suited for high organic loads, a
high recirculation rate and for regions with inexpensive land prices
.Both shallow and deeper pond d epths are currently being applied,
depending on organic load and land availability.

61. Organic Loading Rate
Average organic loading rates expressed in terms of BOD5 for
plant systems without artificial aeration should not exceed 100 to 160
kg/ha·d in order to obtain an effluent quality of 30 mg BOD/l or less
(Metcalf and Eddy 1991, Gijzen and Khondker1997). Odors can develop at
lower loading rates, especially where the sulphate concentration in the
wastewater is greater than 50 mg/l. It seems that duckweed is less
suitable for the treatment of wastewaters containing high BOD loads.
Duckweed systems alone appear to be less suitable for treating wastewaters
containing high BOD loads.

62. Operating Considerations
It includes –
• Labour Requirements
• Initial Work
• Maintenance and Operational Work
• Work Related to Animal Cultivation

63. Transport of fresh duckweed in a wickerwork basket
to the weighing station and adjacent fish pond, using a
wooden board, a
bamboo pole and strings for suspension of the basket
(Bangladesh
Freshly harvested duckweed grown
on diluted sewage
is filled into a wickerwork basket,
where it remains for some time to
allow
some water drainage and pathogen
removal by sunlight irradiation
(Bangladesh).

64. Determination of duckweed wet
weight
using a spring scale and record
keeping (Bangladesh).
Distribution of fresh sewage-grown
duckweed into floating bamboo feeding zone of
fish pond.
The feeding zone prevents the floating duckweed
from
being undiscovered by fish through dispersal in the
fish

65. Harvesting of Duckweed
The quantity and frequency of duckweed harvesting plays a
major role in the treatment efficiency and nutritional value of
the plants. Regular harvesting ensures that the accumulated
nutrients or toxins are permanently removed from the
system.
Optimum standing crop density to achieve highest productivity is
site specific.
Alaerts et al. (1996) reported a standing crop density of 1600
g(wet wt)/m2 for a duckweed-covered sewage lagoon in
Bangladesh.

66. Harvesting Frequencies And Amount

68. Removal Efficiencies
Reliable data on removal efficiency in full-scale duckweed treatment
systems is practically inexistent.
The most relevant study on removal efficiencies in a full-scale
duckweed treatment system in a low-income country was published
by Alaerts et al. (1996). The study focused on a 0.6 ha
plug-flow sewage lagoon covered with Spirodela for 2000-3000
inhabitants in Bangladesh. The lagoon received the effluent of an
anaerobic sedimentation pond with a HRT of 1-3 days. The plugflow’s
depth increased from 0.4 to 0.9 m with a HRT of about 20
days.

72. Comparisons with other Methods

74. Wastewater Treatment Using
Duckweed
• Advantages
This technology is inexpensive to construct and operate, and easy to
implement. Duckweed is a prolific plant, especially in nitrogen-rich
environments, and can be easily used as mulch or a natural soil organic
enrichment.
• Disadvantages
If the flows through the oxidation pond are not properly controlled, there
is a possibility that the duckweed will flow out with the effluent.
Treatment capacity may also be lost during high floods, if the area is not
protected.
• Cultural Aspects
No problems relating to the use of this technology are known to occur.
• Further Development of the Technology
More research through pilot projects is needed in order to refine the
sizing of the ponds used and to determine the correct inoculums of plant
material to achieve a predetermined effluent quality

75. New Approach For Greener & Cleaner
city Model Development

78. • Water Quality Map provides a good visual
picture of pollution status of river
• It can be presented to managers and decision
makers as a good visualization aid
Water Quality Mapping using Biological and
Chemical Indicators

79. Effect of Untreated Wastewater Discharge
Water Quality Map around Dhaka Industrial effluent discharge

80. Shared Responsibility
• The responsibilities do not rest with the
Engineers only.
• Government, Policy Makers, General
Populace, Entrepreneurs should share the
responsibilities
• Good governance in every sector is essential
to ensure ethical management of the
environment

81. 1)Self-purification of
water body
2)Building WWTP
1)Increasing treating
fees for wastewater.
2)Using the wastewater
as resources
3)Recycling
1)Improving
legislation
2) monitoring

83. Media and Environmental Awareness
Erin Brockovich
• The movie portrays the environmental disaster due to contamination of drinking
water at Hinkley, California.
• Chromium (VI), a carcinogen, caused by a Pacific Gas & Energy Ltd.
• The pipeline was constructed in 1952. The company knew that Hinkley GW was
being contaminated through their pipeline but tried to cover up.
• The case was settled in 1996 for $333 million in a direct action law suit.
• Another lawsuit, against this company alleges contamination near PG&E Kettleman
Hills compressor station in Kings County, California

85. In Conclusion
• Professional ethics is essential for ensuring a safe and sound
environment
• The responsibilities rest upon not only on the Engineers but
also on the policy makers, govt. and non-govt. organizations,
donor agencies as well as the general public
• Good governance in every sector is essential to ensure ethical
management of the environment
• Communication between the professionals and policy makers-
end users provides the key to success

86. References
• Alaerts, G. J., Md. M. Rahman, and P.
Kelderman. 1996.Performance analysis of a
full-scale duckweed-covered sewage lagoon.
Wat. Res. Vol. 30, No. 4: 843-852.
• Angerilli, N. P. D., and B. P. Beirne. 1980.
Influence of aquatic plants on colonization
of artificial ponds by mosquitoes and their
insect predators. Can. Entomol. 112: 793-
796.
• Arthur, J. P. 1983. Notes on the design and
operation ofline an agricultural system that
utilizes aquatic plants. J. Aquat. Plant
Manage. 17: 74-75.
• Lueoend, A. 1983. Das Wachstum von
Wasserlinsen (Lemnaceae) in Abhaengigkeit
des Naehrstoffangebots,insbesondere
Phosphor und Stickstoff. Veroeff.
Geobot. Inst. ETH, Stiftung Ruebel, Zuerich 80:
pp.116.
• Mandi, L. 1994. Marrakesh wastewater
purification experiment using vascular
aquatic plants Eichhornia crassipes and
Lemna gibba. Water Sci. Technol. 29: 283-
287.
• Mara, D. D. 1976. Sewage treatment in hot
climates. Chichester. John Wiley.
• Mara, D. D., P. Edwards, D. Clark, and S. W.
Mills. 1993. A rational approach to the
design of wastewater fed fishponds. Wat.
Res. 27: 1797-1799.

87. References
• Reed, S.C., E. J. Middlebrooks, and R.
W. Crites. 1988. Natural Systems for
Waste Management and Treatment.
McGraw-Hill, New York.
• Rejmankova, E. 1982. Proc. 1st Intern.
Wetlands Conf. New Delhi. pp. 397-403.
• Robson, E. 1996. Lemnaceae cleanes
waste and creates protein. Weekend
Independent. pp. 20-21.
• Rodriguez, L. and T. R. Preston. 1996.
Comparative parameters of digestion
and N metabolism in MongCai and
Mong Cai large white cross piglets
having free access to sugar cane juice
and duckweed. Livestock
• Research for Rural Development, Vol. 8.
• cattle. J. Dairy Sci. 60: 161.
• Russoff, L. L., S. P. Zeringue, A. S.
Achacoso, abd D. D.
• Culley. 1978. Feeding value of
duckweed (an aquatic plant. Family
Lemnaceae) for ruminants. J. Dairy Sci.
61: 186.
• Schulz, B. 1962. Wasserlinsen. Die neue
Brehm- Buecherei, Ziemsen,
Wittenberg. pp. 95.
• Shahjahan, M., A. H. Khan, N. Akhtar,
A. S. M. A.

88. Thank You