constructed wetland
Jacky Foo
Message has 2 images. click on source to view them
++++++++
----forwarded message-------
from Liaqat Hayat [liaqat...@gmail.com]
date 18-Jul-2007 20:21
subject File of messages so far
++++
Captions for diagram:
i. One CWL cell is of 60 ft dimension for 500 gallons per day inflow
of sewerage
ii. Alternate bed with vetiver plant/grass or eucalyptus trees
iii. depth 12 inches _ ¾ inches single size crushed stones for 12
inches depth
02 inches_ 1/8 to 3/16 inches top 2 inches sealing layer of stones/
sands
iv Sewerage pipe with perforations
+++++
I have created account with www.iobbnet.org and now will send message
directly through above website. To conclude, I feel following points
have not been sufficiently touched upon or still dealt with :
(1) Odour and mosquitoes problem if associated with vetiver or such a
CWL cell.
2. Size for 5000 gallons daily influent.
3 Experience with the type of filling materials and what is preferable
in this scenario.
4 So far we discussed two types of wetland plants and what about a
third one so that each is used in one cell/pond and can be monitored
for performance in this pilot plant.
My assessment with so far discussion leads me to conceptual design as
per attachment in this case and would very much like comments from you
all to finalize this after all good and bad points including
suggestions indicated in your comments.
Best Regards,
Liaqat Hayat
Jacky Foo
click on link to view image in message
+++++++++
constructed wetland
Submitted by Jacky Foo on Thu, 19/07/2007 - 07:10.
Liaqat Hayat wrote (18-Jul-2007) in
http://www.iobbnet.org/drupal/node/view/970/3303
>......My assessment with so far discussion
>leads me to conceptual design ....(cut)...
>in this case and would very much like
>comments from you all
To Liaqat
I did not ask this basic question earlier......but after seeing your
"conceptual" design, I feel I need to.
(a) have you built a CWL before ?
(b) what types of plants esp wetland plants have you grown or tested
before ?
(c) what special reasons do you have to put Eucalyptus trees in a CWL
cell ?
(P.S: I doubt Eucalyptus will grow in waterlogged conditions)
In Uganda, when I was exposed to new environment, I first looked for
local plants, tested them for their growth and their nutrient removal
and started a plant nursery first. This took 3 months. These were done
for a test CWL site of about 100 m2.
The design of the CWL is the easiest part. The growth of the plants
and fishes for the control of mosquitos need time (and patience).
-----
Jacky Foo
Education: botanist and agricultural microbiologist
http://www.iobbnet.org
Jacky Foo
click on source to see images
+++++++++
constructed wetland: design and plants
Submitted by IOBB Editor on Thu, 19/07/2007 - 08:40.
----forwarded message ----(edited)
Richard Grimshaw [r.gri...@comcast.net]
Here are some very interesting comments from Paul Truong - who is very
experienced in this area
Dick Grimshaw
+++++
From: Paul Truong [tru...@uqconnect.net]
Date: July 18, 2007 5:09:59 PM PDT
To: Richard Grimshaw [r.gri...@comcast.net]
Subject: Re: Fwd: [IOBB-PK-effluent] constructed wetland
++++
LH>Captions for diagram:
>i. One CWL cell is of 60 ft dimension for
>500 gallons per day inflow of sewerage
60X60' ? I think it is too small for this input. The cell size needed
to treat or dispose depends on weather and sunlight, season etc you
just cant plug it from the air.
LH>ii. Alternate bed with vetiver plant/grass
>or eucalyptus trees
Forget Eucalyptus, see table (image), I suggest sorghum or Rhodes to
compare, but remember with sorghum, it is a crop, need replant every
3-4 months.
LH>iii. depth 12 inches _ 3/4 inches single size
>crushed stones for 12 inches depth
> 02 inches_ 1/8 to 3/16 inches top 2 inches
>sealing layer of stones/sands
too shallow , need at least 50cm or 20''
LH>iv Sewerage pipe with perforations
OK and what is the retention time or continuous flow ??
LH>(1) Odour and mosquitoes problem if associated
>with vetiver or such a CWL cell.
Not in a flow thru system or trickle thru, no ponding no smell
LH>2. Size for 5000 gallons daily influent.
need to run a model on this as they are testing it seriously here, we
have to be sure.
LH>3 Experience with the type of filling
>materials and what is preferable
>in this scenario.
Sandyloam to sand
LH>4 So far we discussed two types of wetland plants
>and what about a third one so that each is
>used in one cell/pond and can be monitored
>for performance in this pilot plant.
See above
LH>My assessment with so far discussion leads
>me to conceptual design as per attachment
>in this case and would very much like
>comments from you all to finalize this
>after all good and bad points including
>suggestions indicated in your comments.
Dick, I need a lot of time to do this properly. Tell him to get back
later as I dont the time to go into details, constructed wetland needs
alot of planning and details, not just digging a hole, fill with sand.
He can try but we have to be careful on what we recommend.
Dr Paul Truong
Veticon Consulting Pty Ltd
Email: tru...@uqconnect.net
Website: www.uqconnect.net/veticon
23 Kimba St. Mobile: 0417 198 293
Chapel Hill Tel: (07) 3378 3174
Brisbane Q. 4069 Fax: (07) 3378 3187
Australia International Code: (+61)
Jacky Foo
++++++
----forwarded message-----
From: Lhayat
Subject: Constructed Wetland
Date: Thu, 19/07/2007 - 11:52
My response is as follows
(a) No I have not constructed a CWL before.
(b) I have planned six months for the project after start. I hope that
this e-workshop will enable me to select 3 - 4 plants out of which I
will have a choice to choose two most appropriate plants depending on
their availability and suitability for the treatment in the CWL cell.
Presently I am in the planning stage and start actual work after
finalizing my thoughts now. Probably I will also have to spend same
period in putting up the nursery after selection of the plants.
(c) The only reason for selection of Eucalyptus is that it is grown in
location which are water logged and suck/consume lot of water. In case
of CWL one has condition similar to water logged wet area and it has a
possibility to perform. I am not still sure on this particularly after
the comments received from Dr. Paul Truong. I am inclined to replace
"Eucalyptus" in two cells with "sorghum crop" and have found out from
my botanist friend that it is grown here for cereal etc.
Thanks for your comments and I feel that I will have enough data to
start my project in the month of August and start with nursery first.
I have already identified one functioning nursery and in one portion I
will have growth of these plants. For 2500 square ft wetland cell, I
reckon about 2500 plants.
Regarding tests on plants, I will be using services of biological/
zoological department of the local university.
Regards,
Liaqat Hayat
Jacky Foo
++++++++
-----forwarded message-----
From: Lhayat
Subject: Constructed wetland: design and plants
Date: Thu, 19/07/2007 - 13:01
I am thankful to you for passing on very valued comments of Dr. Paul
Truong of Veticon Consulting pty Ltd and hope to have some more
important contribution from him as we proceed further and also when he
has time to spare. I hope to contact him after a week after we have
some more discussion in the e-workshop.
The sorghum crop is a real possibility for use here and has added
economic advantage for the operator. Dr Paul Truong spoke of running a
model for sizing etc.
It is great and please let me know if he needs more site specific
data.
Regards,
Liaqat Hayat
Jacky Foo
++++++
Vetiver grass - Vetiveria ziz
Submitted by Dick Grimshaw on Mon, 23/07/2007 - 16:42.
Vetiver grass - Vetiveria zizanioides (south Indian cultivar) is FULLY
TESTED and PROVEN, under climatic conditions similar to yours, at
field scale to remove more nutrients and heavy metals from effluent
than other plants. In addition it will grow and survive where other
plants including trees will not. Vetiver hedgerows grown as a buffer
along river, canal, and drain banks will not only reduce effluent
seepage into such water conveyances but will also stabilize the banks,
provide forage, and materials for thatch, mulch, fuel, and
handicrafts. Additionally because of its massive root system and rapid
growth rate, where water and effluent is present, it sequesters high
amounts of carbon. This plant is a WIN WIN plant.
Vetiver grass does the same thing when designed as a special purpose
constructed wetland - in such cases the design (relating to size) must
match the expected effluent inflows. This is where the Australian
model MEDLI can be very helpful.
It is a fallacy that trees will prevent erosion on stream banks. If
you look closely they do not. If you want to grow trees along side a
river plant them back from the river bank, and grow vetiver grass
between the trees and the riverbank. It is even a greater fallacy to
think that tree roots will reduce the high nutrient loads in effluent.
The Vetiver System is the least cost solution, its cost, relative to
hard solutions, is related to the cost of labor. In Pakistan labor is
low cost, so you can do a lot with $10,000 if you use vetiver grass.
Once you have decided on a design, (Vertiver "reedbed" type flow
through system, large communal vetiver wetland, micro vetiver wetland
at outflow of septic tank, or just stream bank buffer and
stabilization) you need to order good quality plant material
(M.P.Singh can help you here), create a nursery and multiply the
plants. (1ha of irrigated nursery can produce over 400,000 vetiver
slips per year - enough to plant 41km of vetiver hedgerow each year -
this would protect about 10km of river bank - or provide sufficient
plant material for 5 ha of vetiver wetland). I doubt that you will
need such large amounts. Once you have a good supply from your vetiver
nursery you can start working on your effluent control project.
Under your conditions where maintenance is generally not very good I
would choose a plant that is tough, resilient and does the job
effectively. Vetiver (south Indian cultivar will do this) Other plants
suggested such as sorghum, eucalyptus, will not work either in the
short or long term, and your project will fail.
As I have mentioned nearly all the information you require, including
images, can all be found on the Vetiver Network website at http://www.vetiver.org
Dick Grimshaw
Jacky Foo
+++++++++++
Vetiver maintenance - lemon grass
Submitted by Jacky Foo on Wed, 25/07/2007 - 18:58.
Dear Dick G. and others
Many thanks for the useful info about "unmanaged" Vetiver plants. I
have not tried grasses in my projects but if the next opportunity
comes, I will do it.
In North west (dry forest) Cambodia, at a 230 ha farm where we dug
many ponds for capturing stormwater. On the embankment of the ponds,
we grow lemon grass since it has commercial value in Cambodia and used
by households.
http://en.wikipedia.org/wiki/Cymbopogon provide some species that are
native in Australia too. Since Vetiver is closely related to other
fragrant grasses such as Lemon Grass (Cymbopogon citratus) and
Palmarosa (Cymbopogon martinii), I wonder if anyone in your vetiver
Network has tried using lemon grass for CWL.
regards
jacky
Jacky Foo
++++++++
Vetiver maintenance - lemon grass
Submitted by M P Singh on Thu, 26/07/2007 - 04:34.
Dear Jacky,
Too much commercial value can also be dangerous.Very poor communities
tend to destroy it and at the end of the day the very purpose is
defeated.
We must keep in mind that our main stress is the engineering
application.
There is a need to give due weightage to the engineering application
and the economics. The choice will definitely vary from place to place
depending on the socio economic status and demography.
Best wishes,
MP
Jacky Foo
++++++++
Vetiver maintenance
Submitted by Jacky Foo on Thu, 26/07/2007 - 07:10.
M P Singh wrote:
http://www.iobbnet.org/drupal/node/view/970#comment-3338
MPS>....Too much commercial value can also be dangerous.
>Very poor communities tend to destroy it and at
>the end of the day the very purpose is defeated.
I could imagine real situation where your scenario would happen,
especially the destructive nature of poor communities in the act of
scavenging or stealing. I do agree with you in this context.
I would also presume that where such a situation could happen and when
stealing or scavenging by poor neigbourhoods do take place, usually
the owners of a property would have some guarding system against
thefts. This happens a lot in most of the countries I worked in too.
In a scenario where Liaqat H has a CWL that is generating products of
economic value, I guess his workers will guard the property because it
also means economuc gain to them.
I have asked Liaqat about maintenance of the CWL that he will build.
Let us await his response to this question.
-----
Jacky Foo
http://www.iobbnet.org
Jacky Foo
++++++++++
Vetiver maintenance
Submitted by M P Singh on Thu, 26/07/2007 - 10:05.
Response to Jacky's post on Thu, 26/07/2007 - 11:40.
Jacky wrote:
>"I would also presume that where such a situation could happen
>and when stealing or scavenging by poor neigbourhoods do take
>place, usually the owners of a property would have some
>guarding system against thefts. This happens a lot in most
>of the countries I worked in too."
Ans.
This is the problem!!! The scavanger is himself the owner and he does
not realise because he has neither contributed nor sweated for the
facilty. I simply commented on the treatment plant being too valuable.
Such poverty does not exist in my part of the country. Liaqat is not
too far away from here. Culture in the entire Punjab region is the
same whether in Pak or India. My parents grew up in that part of
undivided Punjab.
The best would be to have a comparison of known performance results of
various options (of plants) and check for their sustainability.
When we discuss the role as embankment stabilizer, run off water
checker or the effective cleanser we must have comparative numbers,
based on known data.
MPS
Jacky Foo
++++++
proposing that Liaqat visits M P Singh
Submitted by Jacky Foo on Fri, 27/07/2007 - 08:07.
M P Singh on Thu, 26/07/2007
>Liaqat is not too far away from here.
>Culture in the entire Punjab region is the
>same whether in Pak or India.
I agree that a visit by Liaqat H to meet M P Singh would be most
useful. Also Liaqat will be building his first CWL, MP Singh might be
able to show Liaqat a CWL too and discuss some engineering tricks when
it comes to water flow.