location: waterlogged

[Jacky Foo]

Lhayat wrote: (19/07/2007)
>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 had always thought that Eucalyptus trees will die in waterlogged soil conditions (as in a CWL cell/pond) however if grown in normal soil and because it has a deep root system, a plantation of Eucalyptus will sucks deep underground water and can lower ground water level.

Q: if you use Eucalyptus in a CWL cell, what happens when these plants grow into tall trees ?
Would it not reduce sunlight that reaches the adjacent ponds ?

I know that Eucalyptus trees can be used to achieve for zero water discharge, i.e. effluent from CWL is directed by canals into the forest of Eucalyptus which can be harvested for its fuel wood. However I have never heard of growing Eucalyptus in CWL cells.

In any case, as what Paul Truong and Dick Grimshaw indicated, CWL cells need plants that can absorb nutrients (as the primary purpose of CWL is to remove nutrients and then the CWL effluent could be discharged).

If you have enough land and there is an existing forest (or grassland), the simpliest thing to do with the effluent from a septic tanks is to canal the effluent into the forest (or grassland). Efficiency of nutrient removal can be increased by planting selected grasses (high nutrient absorbers) beside these narrow and shallow canals. There is little need for a "masterplan construction" as it is just to dig and create a labyrinth of shallow trenches for water flow. Growing deep rooted trees along the river would then be useful. 
(afterall you have 2500-5000 gallons (11-22m3 per day) of effluent only).

Q: what is the budget for constructing your 10-cell CWL ?
Q: have you measured the outflow of effluent in the river ?

regards
jacky
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[Jacky Foo]

Source: http://www.iobbnet.org/drupal/node/view/970#comment-3316

-----forwarded message-----
From: Lhayat
Subject: Location: Water Logged
Date: Sat, 21/07/2007 - 09:55

Thanks for your comments and like to respond as follows

(a) I am not fimiliar with narrow and shallow canals system
discussed.

Can you suggest me some websites to study more details on this as it
appears to be very simple arragment.

Growing deep rooted trees along the river is simple arrangment but how
it will treat the sewerage water without retension of waste water
around it.

(b) Budget to start with is $10,000 and may increase depending on
exact scope of work we decide to carry out after this e-workshop.

(c) Quantity of effluent in river not much and may be considered 1 - 2
cusec during dry period.

With best Regards,
Liaqat Hayat.