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Waste Water Management (WWM)
Written By psaram42 - 26 June, 2009
Bangalore Analysis sewerage waste water treatment
Water-carried wastes, in either solution or suspension form, that flows in sewage pipes from any house hold, commercial enterprise or an industry is called waste water in general. If it contains mainly human excreta and other organic matter it is called sewage. This sewage with Human excreta and other organic waste is not a waste in the real sense, as it contains recyclable soil enriches called manure and fuel for generation of electricity. This kind of waste from house hold or hospitality industry can be classified as sanitary water discharge. This discharge water is characterized by its physical condition, its chemical constituents, and the bacteriological organisms that it contains. Thus depending on their origin, wastewaters can be classed as sanitary, commercial, industrial, or surface runoff. Industrial waster water can be of different grades like A, B and C. The A grade Industrial wastes being the most dangerous and unacceptable and those Industries producing “A” grade waste water are to be banned at best.
For details of known Sewage treatment, or domestic wastewater treatment, procedure here is a Wikipedia Link.
It is important to note that in a city like Bangalore Sewage ie domestic waste water is disposed using the sanitary (sewage) pipes, to be delevered at the treatment plant. These pipes mostly made out of vitrified porcelain of 6 inches or more diameters. The volume carrying capacity of these pipes is squarely proportional to its diameter. Therefore if the volume exceeds the limit there will be backlog resulting in spillage of the man holes. If this spillage can find its way to storm water drains and or the sewage is directly let into storm water drains, by design leagally / illegaly the result will be pollution of the lakes into which these storm water drains are currently designed to discharge. This aspect has already been discussed briefly in an earlier thread.
The SWD Planning aspects have been discussed elsewhere in PRAJA, where a new system being used in other developed countries like Great Britton, Australia and USA etc was discussed. That design philosophy is entirely different, than that existing at present in Bangalore. This new (as far as Bangalore is concerned) philosophy is to use the storm water to charge the ground water table at the rain fall site directly. This is no doubt an alternate system than that being used currently in our city of Bangalore, which is to use the lakes for storing the rain water on surface instead of charging the under ground water table. Thus the crrent technology happens to be the oldest technology of Roman origin. However let us be clear that what is discussed in this thread is not the design philosophy of SWD. Please do not discuss SWD here which will only confuse the issue being discussed here viz domestic wastewater management. For this to take place the sewage water has to be carried up to before delivering at the treatment plant by proper sized pipes. There should be no spillage till the delivery at the STP.
Unfortunately here in Bangalore the SWD design philosophy so far has been to collect all the storm water for discharging into designated Lakes, with no ground water charging at all. So at preset in Bangalore these Drains are supposed to discharge the rain water to particular designated lakes. These are many times open drains at many locations.
The concept of ground water table charging directly at contiguous catchment’s locations is attractive too, on the other hand. No doubt it should be examined. This is addressed in a different thread. Not here please.
COMMENTS
RKCHARI - 26 June, 2009 - 12:09
The above comment by Mr. Ananthram is substantially correct. The objective of every Municipality should be to recharge ground water table in the first instance. Rain also falls directly into open lakes. Given Indian public health conciousness, open lakes are more a health hazard than beauty spots unless the authorities maintain the lakes as a recreational spot. That too can be done with crystal clear water for sports purposes, but that requires a people friendly Government.
By avoiding open storm water drains, covering it with permeable pavers with a holding, yet infiltrating tank underneath, rainfall gets temporarily collected in these underground tanks on either side of an existing road. I say temporarily because the tanks come with a mechanisim which enables storm water to get absorbed to ground water table levels in a more gradual and in a disbursed manner. Consequently storm water does not have to "go anywhere".
The technology is not expensive nor it is complicated. Moreover there is no maintenance whatsoever. Additionally, Municipalities can also plan to re-do roads (at least the smaller 30 to 40 feet ones inside colonies - the various crosses and mains) with ecologically sustainable road surfaces all of which will act as absorbent surfaces when rain falls. So there will never again be water logging on these roads, no open drains and lots of additional space to grow trees, grass and other green shrubs etc.
Is this a dream? No, absolutely not. Can be easily achieved if there is public support and Government will to make life comfortable and pleasant for its citizebry. Ironically, only today the newspapers announce that the State Cabinet has sanctioned Rs. 150 crores for "tackling the storm water menace"!!
Best wishes,
R.K.Chari
psaram42 - 28 June, 2009 - 15:32
“Several thousand miles of such ecologically sustainable roads dot the world over - even in countries like Indonesia and Malaysia.”
Yes why cant us? I sincerely hope we in India pick the thread at least now, to have the benefit of this proven technology without wasting any more time. I believe the present Karnataka government has allocated Rs 15 Million for remodeling storm water drains. Let us Hope for some positive output at least now.
srkulhalli - 28 June, 2009 - 15:31
RK Chari,
Excellent information. Please do send the presentation to srkulhalli@yahoo.com. Will read it with patience :) and also try to incorporate in the new standards doc that we are creating !
I get what you are saying, but is there a way to adapt this solution to the existing situation. Given that most of urban roads in Bangalore have already been built, where do we go from here ? For eg: can the existing storm water drains be modified with pits underneath to sink of the water rather than expect it to flow from there.
What you suggest looks neat because it doubles up as rain water harvesting, something the city sorely needs. But we must cross the i's and the t's and make sure it works, is low cost and low on maintaenance.
Need more info on storm water management for roads
srkulhalli - 28 June, 2009 - 07:50
In one of the discussions I was having with BDA engineers, the topic of storm water management came up. Basically to go to lane based driving, which will enhance driving safety and pleasure for all, it is critical that the roads are pothole free. There is no point having well planned , laned roads if they are full of potholes as that would discourage drivers from driving on lanes, as their goal becomes to avoid potholes.
The primary reason for potholes is the rain water which collects on the road. Though there are storm water drains, over time they become ineffective for the following reasons
1. Garbage and especially plastic starts collecting in the channels(chutes from road to the drain) which results in blockages
2. Similarly silt fills up in the channels preventing collection
3. Shops etc cement their frontage and over the storm water drain without giving an channels(or chutes) to the storm water drain. As a result the rain water has no where to go.
Ideally BBMP should maintain periodically and there should be strict regulation. BUt a good design is one which is low on maintaineance to start with. What has been propsed seems to be at least one alternative. Can you send any documentation on the above. As Ananth might be aware, I am in the process of putting in documentation on good road design practices/standards and this is an area where we need some good inputs
Suhas
psaram42 - 26 June, 2009 - 10:21
The existing twin KC Valley plants are treating about 250 MLD sewage water from some places in the KC valley area.
It is known that the Lake has several other inlets (SWD) which discharge untreated sewage water into the Bellandur Lake, as reported on Praja earlier. Mr. RK Chari has suggested that the above culprit inlet water can also be treated separately before being discharged in to the lake. This extra requirement however has to be brought to the notice of the authorities concerned.
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