The latest facebook fad is to check in at the Chhatrapati Shivaji Terminus (because everyone always seems to be either coming to, or leaving from Mumbai, with a status: 'I *heart* Mumbai' or something equally generic.
And everytime I read these generic statuses, I feel my heart burn with 'Mumbaisickness'. Mumbaisickness: a virus that attacks everyone who encounters this city and eats away at its victims' hearts until the victim is forced once again to return. No vaccinations have been invented, no medicine prescribed; Because even though the term is Mumbai'sickness', it isnt really a disease! Oh no! On the contrary it has an opposite effect. It gives soul-weary, heart-hungry people rootlets, a base, a home; With Dreams/without Dreams, the city sucks you in. And as you disappear amidst the lights and become one of its 13 million, quite suddenly, rather strangely, the micro comes into focus. You find yourself recognizing individual acts of charity and compassion. And either you find YOURSELF becoming more charitable and compassionate, or absolutely callous and indifferent- and thats when you know you're through. You cant struggle against 'Mumbaisickness' any longer. It has become part of you.
Yet, anyone who has stayed in Mumbai knows its terrors; The infrastructure bursting through the seams as it tries to hold the ever increasing population, the scores and scores of 'informal housing'- a polite term for slums. Mumbaisickness in its manic focus on the micro, loses the idea of the city as a whole. We- The Infected, fail to see the less sexy, absolutely necessary Mumbai projects that affect our lives, and everyone-we-know's lives, for better or for worse.
In a wild moment when I sought to unearth all the implicit assumptions in my life I decided that I had to learn more.
This led to me coming back to India for a week to work on the waste water disposal system. The next few paragraphs will describe what I learned.
I need to fill in my opening paragraph with a more detailed description of the water piping infrastructure during the British rule. For the time being, dear reader, bear with me and allow me to just say that until the 1980s, Mumbai had a combined water piping and sewage system. By the time the sewage reached the sea, the BOD had decreased and it had become diluted. However, as the population expanded, it became clear that a separate waste water collection network along with water treatment plants were required. Note- that until the 1980s we had no water treatment facilities. The original combined system is now only used for storm water drainage because of the large diameter of the pipes.
Current waste water collection covers 40-45% of the city. Though it is easy laying separate waste water collection pipelines for buildings and cooperative housing societies, it is incredibly difficult to lay such pipelines for slum dwellers. This is because of the density of the slums and the lack of toilets. A scheme funded by the World Bank was dreamed up to provide toilet blocks for slums with an underground drainage system. However, the World Bank had 'local participation' as a criterion and hence each household was expected to pay Rs 100 in order to use the facilities. Unused to having to pay for services, very few households complied and the scheme failed. To learn more, read this article.
Currently some toilets have septic tanks attached and the waste water after a give retention period is then washed out through the nullahs into the uncomplaining, misused, abused Mithi river. Current schemes to a) Treat the nullahs themselves b) Divert the nullahs into a huge waste water treatment plant. If the nullah is to be diverted then care must be taken that adequate disaster management precautions must be taken.
Mumbai has been built on reclaimed land - For a history of land reclamation in Mumbai refer to this- Don't think reclamation has stopped either! The link I've embedded in this post describes the current aggressive land reclamation strategy for development projects the city desperately needs! The Bandra Worli Sealink is one such project. (Land reclamation for this project may have had an adverse effect on tides in some parts of Bombay. Refer to this link for more details.) And when are we reminded of this the most? When the monsoon and high tides hit the city simultaneously the sea reclaims what it has lost for its own. Why only a couple of weeks ago in Dadar, high tides caused severe flooding
Such a situation might result in either the water nullah backflowing and flooding the city or water overflowing into the sea without being adequately treated. Flap gates and other precautionary measures must be taken for both situations.
It could be said that solutions a) and b) proposed above are a tacit acceptance of the de facto status quo. Now, now the last was a snide and uncalled for remark. I have to add that there are still vast efforts being put into building public toilets in Mumbai- the following is an example. No I wasnt being serious again- a dreadful habit I've fallen into! But honestly- forget the over hyped? 35 lakh public toilet. Just imagine providing sanitation to the 8 million slum dwellers who live back to back, a hand to mouth existence in the midst of this city! Isn't it an awesome and terrifying proposition?
So lets skim over it and hope that in time solutions will be found and concentrate on the next step of the problem- Water treatment! A topographical study was carried out in 1995 that divided Mumbai into 7 zones- Colaba, Worli, Bandra, Ghatkophar, Bhandup, Malad, Versova. Treatment plants were proposed to be built in the low lying areas of these regions in order for a gravity driven procedure to collect sewage. At the time this survey was carried out- the importance of maintaining the mangrove coverage in Mumbai was not factored in. Therefore single stage aeration lagoons were built in these areas to treat sewage. Why aeration lagoons? They were state of the art technology at that time. In addition they generated very little sludge. The disposal of sludge is very difficult. However, aeration lagoons occupy a large surface area- this means that several mangroves were cut down at that time to build these aeration lagoons.
Now, the quality of the waste water at the outlet of the aeration lagoons does not meet the BOD/COD standards prescribed by the pollution board of India. I am still unclear now as to why a single stage aeration lagoon was built and not a double or triple stage process. Did the standards increase over time or did the quality of the sewage deteriorate as the number of people expanded?
Whatever the answer to that question might be, the water treatment facilities need to be improved. Multi stage aeration lagoons were considered, however, as they would occupy a much larger area, and in several of the sites entail further clearance of mangroves, an activated sludge process was recommended instead. Clearly, in this new scenario, the disposal of the sludge will be a problem that will have to be contended with. The process will also require vast amounts of energy. Simultaneous generation of biogas from the sewage has been proposed which can partially cover the energy costs.
A major problem is that no lagoon/nothing exists in Malad currently for waste water treatment. Therefore, whatever be the process, a waste water plant has to be built in Malad and this will involve the cutting down of a lot of mangroves- 35 ha to be precise! Can an alternative site be chosen? It would be very energetically expensive- in terms of pumping to choose another site. This is a tradeoff that will have to swing one way or the other. There are other problems with the other sites as well. For example, in Bandra, the land on which the facility was going to be built is in the hands of Reliance. This is because Reliance had got the contract to build the second proposed sealink (an idea which has now been shelved). The land has still not been transferred back.
Why do these waste water treatment facilities take such a long time to build? This is because field work has to be carried out to survey each site. Most of this field work is done in areas which are covered with mangroves. Special permission needs to be taken to do work within 50 m of mangroves and this takes time. In 1995, a GIS database of manholes in Mumbai was built up. However, over the years roads have changed and this database has not been updated. Therefore, it is impossible to reply on this database for information and field work is a necessity. In addition prior to the execution of any project an environmental impact assessment and a disaster management plan need to be in place. The approval of such plans takes time
What is the administrative process for the design of this plant? MCGM comes up with a design for the plant with an estimate of how much the plant costs. MCGM then throws the process up on accepts tender offers- basically contractors then pitch their offers to build the plant. They are not constrained to use the MCGM design but have to ensure that the plant meets certain standards. An interesting improvement in the process is that now the contractor not only has to guarantee that the plant will work but also that he/she will take care of operating the plant. This is a positive step to ensure the plant runs at an acceptable standard.
The current work that I am doing in Mumbai is carrying out an independent review of the Bhandup waste water plant. I have seen that the uncertainty analysis carried out for many projects is not rigorous. During the first monsoon the Ghatkopar aeration lagoons were overflowing as they had not been designed to accommodate large flows of water during the monsoon. I hope to make this analysis more rigorous.
Another thing that I noticed was that most of the plans are based on the fact that Mumbai has adequate water- no water recycling of sewage has been thought about. Mumbai gets most of its water supply from dams located out of the city. I am not sure about the status of this water supply. I do know that rain water harvesting has been made compulsory in the city- but there has been very little follow through. Some colonies have been procative about recycling gray water but otherwise not much has been accomplished.
The above is a detailed description of the waste water disposal projects going on in Mumbai
And everytime I read these generic statuses, I feel my heart burn with 'Mumbaisickness'. Mumbaisickness: a virus that attacks everyone who encounters this city and eats away at its victims' hearts until the victim is forced once again to return. No vaccinations have been invented, no medicine prescribed; Because even though the term is Mumbai'sickness', it isnt really a disease! Oh no! On the contrary it has an opposite effect. It gives soul-weary, heart-hungry people rootlets, a base, a home; With Dreams/without Dreams, the city sucks you in. And as you disappear amidst the lights and become one of its 13 million, quite suddenly, rather strangely, the micro comes into focus. You find yourself recognizing individual acts of charity and compassion. And either you find YOURSELF becoming more charitable and compassionate, or absolutely callous and indifferent- and thats when you know you're through. You cant struggle against 'Mumbaisickness' any longer. It has become part of you.
Yet, anyone who has stayed in Mumbai knows its terrors; The infrastructure bursting through the seams as it tries to hold the ever increasing population, the scores and scores of 'informal housing'- a polite term for slums. Mumbaisickness in its manic focus on the micro, loses the idea of the city as a whole. We- The Infected, fail to see the less sexy, absolutely necessary Mumbai projects that affect our lives, and everyone-we-know's lives, for better or for worse.
In a wild moment when I sought to unearth all the implicit assumptions in my life I decided that I had to learn more.
This led to me coming back to India for a week to work on the waste water disposal system. The next few paragraphs will describe what I learned.
I need to fill in my opening paragraph with a more detailed description of the water piping infrastructure during the British rule. For the time being, dear reader, bear with me and allow me to just say that until the 1980s, Mumbai had a combined water piping and sewage system. By the time the sewage reached the sea, the BOD had decreased and it had become diluted. However, as the population expanded, it became clear that a separate waste water collection network along with water treatment plants were required. Note- that until the 1980s we had no water treatment facilities. The original combined system is now only used for storm water drainage because of the large diameter of the pipes.
Current waste water collection covers 40-45% of the city. Though it is easy laying separate waste water collection pipelines for buildings and cooperative housing societies, it is incredibly difficult to lay such pipelines for slum dwellers. This is because of the density of the slums and the lack of toilets. A scheme funded by the World Bank was dreamed up to provide toilet blocks for slums with an underground drainage system. However, the World Bank had 'local participation' as a criterion and hence each household was expected to pay Rs 100 in order to use the facilities. Unused to having to pay for services, very few households complied and the scheme failed. To learn more, read this article.
Currently some toilets have septic tanks attached and the waste water after a give retention period is then washed out through the nullahs into the uncomplaining, misused, abused Mithi river. Current schemes to a) Treat the nullahs themselves b) Divert the nullahs into a huge waste water treatment plant. If the nullah is to be diverted then care must be taken that adequate disaster management precautions must be taken.
Mumbai has been built on reclaimed land - For a history of land reclamation in Mumbai refer to this- Don't think reclamation has stopped either! The link I've embedded in this post describes the current aggressive land reclamation strategy for development projects the city desperately needs! The Bandra Worli Sealink is one such project. (Land reclamation for this project may have had an adverse effect on tides in some parts of Bombay. Refer to this link for more details.) And when are we reminded of this the most? When the monsoon and high tides hit the city simultaneously the sea reclaims what it has lost for its own. Why only a couple of weeks ago in Dadar, high tides caused severe flooding
Such a situation might result in either the water nullah backflowing and flooding the city or water overflowing into the sea without being adequately treated. Flap gates and other precautionary measures must be taken for both situations.
It could be said that solutions a) and b) proposed above are a tacit acceptance of the de facto status quo. Now, now the last was a snide and uncalled for remark. I have to add that there are still vast efforts being put into building public toilets in Mumbai- the following is an example. No I wasnt being serious again- a dreadful habit I've fallen into! But honestly- forget the over hyped? 35 lakh public toilet. Just imagine providing sanitation to the 8 million slum dwellers who live back to back, a hand to mouth existence in the midst of this city! Isn't it an awesome and terrifying proposition?
So lets skim over it and hope that in time solutions will be found and concentrate on the next step of the problem- Water treatment! A topographical study was carried out in 1995 that divided Mumbai into 7 zones- Colaba, Worli, Bandra, Ghatkophar, Bhandup, Malad, Versova. Treatment plants were proposed to be built in the low lying areas of these regions in order for a gravity driven procedure to collect sewage. At the time this survey was carried out- the importance of maintaining the mangrove coverage in Mumbai was not factored in. Therefore single stage aeration lagoons were built in these areas to treat sewage. Why aeration lagoons? They were state of the art technology at that time. In addition they generated very little sludge. The disposal of sludge is very difficult. However, aeration lagoons occupy a large surface area- this means that several mangroves were cut down at that time to build these aeration lagoons.
Now, the quality of the waste water at the outlet of the aeration lagoons does not meet the BOD/COD standards prescribed by the pollution board of India. I am still unclear now as to why a single stage aeration lagoon was built and not a double or triple stage process. Did the standards increase over time or did the quality of the sewage deteriorate as the number of people expanded?
Whatever the answer to that question might be, the water treatment facilities need to be improved. Multi stage aeration lagoons were considered, however, as they would occupy a much larger area, and in several of the sites entail further clearance of mangroves, an activated sludge process was recommended instead. Clearly, in this new scenario, the disposal of the sludge will be a problem that will have to be contended with. The process will also require vast amounts of energy. Simultaneous generation of biogas from the sewage has been proposed which can partially cover the energy costs.
A major problem is that no lagoon/nothing exists in Malad currently for waste water treatment. Therefore, whatever be the process, a waste water plant has to be built in Malad and this will involve the cutting down of a lot of mangroves- 35 ha to be precise! Can an alternative site be chosen? It would be very energetically expensive- in terms of pumping to choose another site. This is a tradeoff that will have to swing one way or the other. There are other problems with the other sites as well. For example, in Bandra, the land on which the facility was going to be built is in the hands of Reliance. This is because Reliance had got the contract to build the second proposed sealink (an idea which has now been shelved). The land has still not been transferred back.
Why do these waste water treatment facilities take such a long time to build? This is because field work has to be carried out to survey each site. Most of this field work is done in areas which are covered with mangroves. Special permission needs to be taken to do work within 50 m of mangroves and this takes time. In 1995, a GIS database of manholes in Mumbai was built up. However, over the years roads have changed and this database has not been updated. Therefore, it is impossible to reply on this database for information and field work is a necessity. In addition prior to the execution of any project an environmental impact assessment and a disaster management plan need to be in place. The approval of such plans takes time
What is the administrative process for the design of this plant? MCGM comes up with a design for the plant with an estimate of how much the plant costs. MCGM then throws the process up on accepts tender offers- basically contractors then pitch their offers to build the plant. They are not constrained to use the MCGM design but have to ensure that the plant meets certain standards. An interesting improvement in the process is that now the contractor not only has to guarantee that the plant will work but also that he/she will take care of operating the plant. This is a positive step to ensure the plant runs at an acceptable standard.
The current work that I am doing in Mumbai is carrying out an independent review of the Bhandup waste water plant. I have seen that the uncertainty analysis carried out for many projects is not rigorous. During the first monsoon the Ghatkopar aeration lagoons were overflowing as they had not been designed to accommodate large flows of water during the monsoon. I hope to make this analysis more rigorous.
Another thing that I noticed was that most of the plans are based on the fact that Mumbai has adequate water- no water recycling of sewage has been thought about. Mumbai gets most of its water supply from dams located out of the city. I am not sure about the status of this water supply. I do know that rain water harvesting has been made compulsory in the city- but there has been very little follow through. Some colonies have been procative about recycling gray water but otherwise not much has been accomplished.
The above is a detailed description of the waste water disposal projects going on in Mumbai
