Technologies

Biological Waste Water Treatment Plant [Nepal]

Waste Water Treatment by the use of Reed Bed Technology

technologies_1179 - Nepal

Completeness: 67%

1. General information

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:
SLM specialist:

Thapa Kripa

Kathmandu University

Nepal

SLM specialist:

Mahat Sabnam

Kathmandu University

Nepal

SLM specialist:

Newa Manashree

Kathmandu University

Nepal

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
Kathmandu University (KU) - Nepal

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

The technology adopted is a treatment plant that treats and purifies waste water being discharged from the hospital biologically.

2.2 Detailed description of the Technology

Description:

It is located in Dhulikhel Hospital premises, Kavre. This treatment plant purifies the waste water being discharged from the hospital biologically on a daily basis.
Biological action takes place in the horizontal and vertical reed bed with the help of bacteria present in the root nodules of Reed plant. The Reed plant helps in spreading the oxygen through its roots. Anaerobic decomposition takes place with the help of oxygen which is spread by the roots.

Purpose of the Technology: The main purpose of this plant is to make the water less toxic so that it does not pose any danger to the human health. It is a biological process in which the Reed plant treats the waste water coming from the hospital.

Establishment / maintenance activities and inputs: Dhulikhel Hospital Constructed Wetland (DHCW) was commissioned in July 1997. The design of DHCW was designed for an average waste water volume of 10m3/ day. But at present, the waste water production is in the range of 75m3/day. Recently, it has been expanded and designed to treat the waste water volume up to 90m3/day.
The plant is maintained by the specialists themselves and the investors are the hospital owners. The task of planning, design, drawing and estimates for the expansion was undertaken by ENPHO (Environment and Public Health Organization ) in association with WATSAN (Water and Sanitation) solution.

Natural / human environment: The treatment plant needs gravel for filtration in horizontal flow bed where the reed bed plant is planted. In addition, sand is required for filtration in vertical flow bed. A slight slope is maintained for the water to flow in one direction.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Nepal

Region/ State/ Province:

Dhulikhel

Further specification of location:

Kavre

Specify the spread of the Technology:
  • evenly spread over an area
If the Technology is evenly spread over an area, specify area covered (in km2):

0.002036

Comments:

Total area covered by the SLM Technology is 0.002036 m2.

The total area covered by the SLM technology at Dhulikhel Hospital was found to be 4 ropanies that is 2036m2=0.002036km2

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through projects/ external interventions

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • improve water quality

3.2 Current land use type(s) where the Technology is applied

Waterways, waterbodies, wetlands

Waterways, waterbodies, wetlands

  • Drainage lines, waterways
Comments:

Major land use problems (compiler’s opinion): Biological wastes from the hospital has a high chance in contaminating the area when disposed recklessly.

Major land use problems (land users’ perception): The water is safe to use for irrigation purpose.

Future (final) land use (after implementation of SLM Technology): Other: Ow: Waterways, drainage lines, ponds, dams

3.5 SLM group to which the Technology belongs

  • wetland protection/ management
  • waste management/ waste water management

3.6 SLM measures comprising the Technology

vegetative measures

vegetative measures

  • V5: Others
management measures

management measures

  • M6: Waste management (recycling, re-use or reduce)
Comments:

Main measures: vegetative measures

Secondary measures: structural measures

Type of agronomic measures: better crop cover, contour planting / strip cropping

Type of vegetative measures: aligned: -linear

3.7 Main types of land degradation addressed by the Technology

other

other

Specify:

Main causes of degradation: discharges (point contamination of water) (Sewage), other human induced causes (specify) (Infected Water), (Hospital Waste Water)

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Layout of the Biological Waste Water Treatment Plant is given below:

Location: Dhulikhel. Kavre

Technical knowledge required for field staff / advisors: high (Engineers)

Main technical functions: improvement of water quality, buffering / filtering water

Secondary technical functions: increase / maintain water stored in soil, increase of groundwater level / recharge of groundwater, water harvesting / increase water supply, increase of biomass (quantity)

Contour planting / strip cropping
Material/ species: Norcot (Phragmites karka)

Aligned: -linear
Vegetative material: T : trees / shrubs
Number of plants per (ha): 6 p/m2
Vertical interval between rows / strips / blocks (m): 4 p/m2
Spacing between rows / strips / blocks (m): 0.15

Trees/ shrubs species: Reed bed

Wall/ barrier
Vertical interval between structures (m): S,C
Spacing between structures (m): 10 mm
Depth of ditches/pits/dams (m): 20-40 mm

Vegetation is used for stabilisation of structures.

Change of land use practices / intensity level: From random to controlled

Author:

Kripa Thapa

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Rupees

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

103.0

4.3 Establishment activities

Activity Timing (season)
1. Earthwork in excavation in foundation, drain, pipe trench and lead Dry Day
2. Earth work in refilling including watering and ramming Dry day
3. Dry flat brick soiling for 10 m2 Dry Day
4. Edge brick soiling in 1.6 cm and pointing in 1.2 cm for 10 m2
5. Dry edge brick soiling in 1:6 cm for 10 sq m

4.4 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Earthwork in excavation unit 1.0 122.21 122.21
Labour Earth work in refilling including watering and ramming unit 1.0 87.29 87.29
Labour Edge brick soiling (mason) unit 1.0 5293.83 5293.83
Construction material Brick unit 1.0 253.92 253.92
Construction material Sand unit 1.0 3412.38 3412.38
Construction material Wood unit 1.0 1000.0 1000.0
Other Mason unit 1.0 1470.0 1470.0
Total costs for establishment of the Technology 11639.63
Total costs for establishment of the Technology in USD 113.01

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The most determinate factor affecting the cost is the labour cost.

5. Natural and human environment

5.1 Climate

Agro-climatic zone
  • humid
  • sub-humid

Thermal climate class: tropics

Thermal climate class: subtropics

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms:
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
Indicate if the Technology is specifically applied in:
  • concave situations

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • coarse/ light (sandy)
Topsoil organic matter:
  • low (<1%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil texture (topsoil): Filtration is vertical reed bed

Soil fertility is medium

Topsoil organic matter is covered with gravel

Soil drainage / infiltration is good and filtration occurs through voids in sand and gravel

Soil water storage capacity is medium

5.4 Water availability and quality

Availability of surface water:

good

Water quality (untreated):

unusable

Comments and further specifications on water quality and quantity:

Availability of surface water is good during monsoon

Water quality (untreated) is unusable since it is biological and medical waste

5.5 Biodiversity

Species diversity:
  • low
Comments and further specifications on biodiversity:

Only one species of plant is planted

5.6 Characteristics of land users applying the Technology

Relative level of wealth:
  • average
Individuals or groups:
  • employee (company, government)
Level of mechanization:
  • manual work
  • mechanized/ motorized
Gender:
  • women
  • men
Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users

Difference in the involvement of women and men: The treatment plant provided treated water which is mainly used for irrigation purpose. There is an equal involvement of men and women in the field.

5.7 Average area of land used by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
  • small-scale

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • company
Land use rights:
  • communal (organized)
Water use rights:
  • open access (unorganized)
Comments:

SLM technology is used by the hospital specialists. However, the water is openly accessible.

5.9 Access to services and infrastructure

health:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
Irrigation:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Water availability and quality

drinking water availability

decreased
increased

drinking water quality

decreased
increased

water availability for livestock

decreased
increased

water quality for livestock

decreased
increased

irrigation water availability

decreased
increased

irrigation water quality

decreased
increased

Socio-cultural impacts

SLM/ land degradation knowledge

reduced
improved

livelihoods and human well-being

reduced
improved
Comments/ specify:

the technology has increased the knowledge about irrigation and sanitation. This has indeed helped in better livelihoods and health.

Ecological impacts

Water cycle/ runoff

water quality

decreased
increased

groundwater table/ aquifer

lowered
recharge
Biodiversity: vegetation, animals

biomass/ above ground C

decreased
increased

6.2 Off-site impacts the Technology has shown

water availability

decreased
increased

reliable and stable stream flows in dry season

reduced
increased

buffering/ filtering capacity

reduced
improved

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change
Season increase or decrease How does the Technology cope with it?
annual temperature increase well

Climate-related extremes (disasters)

Meteorological disasters
How does the Technology cope with it?
local rainstorm well
local windstorm not known
Climatological disasters
How does the Technology cope with it?
drought not known
Hydrological disasters
How does the Technology cope with it?
general (river) flood not known

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
reduced growing period well
Comments:

In 2007, expansion of the plant was proposed to treat the waste water volume up to 90m3/day.

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Long-term returns:

slightly positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

positive

Long-term returns:

very positive

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
This technology has provided positive results for irrigation purpose.
There has also been an increase in water availability.
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
The purification of water from the hospital has been used for various purposes.

How can they be sustained / enhanced? Frequent cleaning of the chambers should be carried out.
This technology has been proved to be very cost effective.

How can they be sustained / enhanced? Periodic checking of the tanks and plants for any fault should be done.
This plant has been easily managed by the staff of Dhulikhel Hospital.
This technology provides opportunity to create/restore valuable wetland habitat.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
The treatment plant may not be tested regularly. Engineers and specialists should be concerned about the matter.
The water output may not be safe for drinking. People should be made aware about boiling and filtering the water before drinking.

7. References and links

7.1 Methods/ sources of information

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