Friday, February 20, 2015

Drainage system, cause of health hazards in Mumbai


  1. Not enough water is available to flush out human waste.
  2. Stickiness in the stool causes it to stick to pipes of drains and water cannot push it further.
  3. Drains overflow and the dirty water comes on the roads.
  4. Drain water enters houses during rains.
  5. Water from the drains mixes with drinking water.
  6. Water from these drains also causes many ailments that contain harmful pathogens.
  7. Drains act as a breeding ground for a lot of mosquitoes and insects, bandicoots, rodents, and such pests.
  8. The municipal department is not responsive to complaints.
  9. De-silting of the drains is not done by the department regularly.
  10. When the drains are cleared, debris is put on the side of the road.
  11. Many manholes are not properly covered because of thefts.
  12. For cleaning main drainage pipes often minors are employed, many deaths are reported due to poisonous gases those emit from the sludge in the pipes.
  13. Many drains are open.
  14. Open drains results in a bad stink in the area.
The first cause is the most important in all the above-mentioned causes for failure of drainage system. Basic theory behind this system to be successful is that, copious quantity of water is required to flush out waste into the main drainage pipes. For that, minimum 36 liters of water must gush out within 30 seconds to push the stool away into the drainage pipe from the toilet boot. A human is normally expected to visit toilet at least two or in some cases three times in a day to cleanse. That comes to about 100 liters of water for flushing on an average per head. In addition to that water is required to do many other daily needs such as washing, cleaning pots, bath, cleaning floors, cleaning cars, gardening, cooking and drinking. In all 200 liters of water is recommended per head per day for comfortable cleansing and other daily needs. Whereas at present BMC is able to give only meager 40 liters of water per head per day.
To understand this problem we divided system in three parts. First part in the toilet room, second part in the building premises, and third part is in the main drainage pipe.
First part - here we see that stool is deposited in the boot of the toilet and after finishing the cleansing washing of body part is done after that flushing is expected to push the feces into the drainage pipe of the building. If this happens properly, it is noticed that first part has worked well. However, many a times due to sticky nature of the stool it is not cleansed properly. At that time, special human efforts are required to remove it from the boot. That needs additional water to do that and in addition to it some scratching of boot. That could be anywhere around 5 to ten liters per stool. Adding that comes to total water requirement to around 50 to 56 liters. Total daily need of water for flushing comes to about 145 liters per head per day. This observation shows that out of total water requirement of a person more than half of it goes in flushing. This is required to make this drainage system to function successfully. However, since BMC is supplying only about 40 liters of water per person. Our drainage system cannot function successfully. This has led the observers to think of another more suitable system to dispose off stool.
Provided first operation is completed satisfactorily; in second operation that stool along with accompanying flushing water passes with much ease through the building's drainage pipes down into the chamber called inspection chamber. There it lands with mush momentum and is carried into the ground level drainage pipe. Here the stool is stuck up due to reduction in speed of flushing water. Due to sticky nature of human waste, it stays holding to the walls of that pipe. Flushing water and other water keeps flowing passing over it. As a result, this human waste continues to accumulate in these pipes who are generally laid down in horizontal position. Process of decomposition may continue in that place accompanying other waste that is pushed through the same drainage pipes. Here the problem begins to show up. Often we all know that these drainage pipes need to be cleaned occasionally by physical efforts. This cleaning is not done always properly. This accumulated muck carries with it all types of pathogen according to what diseases people in the premises suffer from. During its remaining in the pipes many types of objectionable insects, such as mosquitoes, flies, cockroach, continue to breed on the available protein and carbohydrates. Gases emitting from this muck flow through went pipes usually connected to the inspection chamber and come in outer atmosphere. These gases contain many pathogens along with the vapor that it contains. Eventually, these many dangerous pathogens spread in the building and surrounding areas. Eventually, they infect people in the vicinity. So long as, this drainage system continues spread of these multitude of pathogens will continue to affect health of people of this city. It is this cause, for which we have to find out a more safe alternative system to dispose off sewerage of residential buildings.
Drainage system has third segment. The main drainage system is supposed to carry away sewerage to its ultimate destination. It is largely observed that most muck remains in the pipes under the buildings but some may eventually get pushed in the main drainage pipes those are normally put under ground our streets. Since the total water input in the system is miserably low, problem of pushing this muck further continues. We know from repeatedly our BMC has to do cleansing of these pipes with mainly human efforts since most machines have limited capacity to do this work. I have noticed that minors are employed to do this work. It is a crime to appoint this boys but our BMC is doing that crime under very nose of police. Nobody bothers but we have to take a serious note of this practice also while discussing this problem.
Actually, the very purpose of using this drainage system is to allow our waste to flow easily through all these pipes and reach the end without hassles. In reality, we see that it does not happen. The only way to make this system work efficiently is to supply enough or enormous quantity of water to push the stool and other waste through these all pipes easily to the end. The problem is that our BMC is not in position to acquire reasonable quantity of water to fulfill this requirement. As a result, we have to find out other more efficient and least bothering system to dispose off house waste sewerage; preferably maintenance free.
Some come with suggestion of septic tank. Septic tank has been found to be worse than drainage system. The spread of pathogens due to septic tank is more than what drainage system causes. Therefore, that is not acceptable to our city. Moreover, that system can work for smaller population. The type of population our city is managing, septic tank is no solution.
Given here are some of the complains about Septic Tank
  • Septic Tank overflows in the surrounding places creating nuisance.
  • Since decomposition in Septic Tank is done by anaerobic microbes stink spreads in the surrounding areas.
  • Septic Tank gives out fumes those contain pathogen of many diseases, which may be people who use it are suffering.
  • Many pests such as cockroach, flies, mosquitoes and more, breed in and around Septic Tanks.
  • A very regular inspection and care is essential to keep this system in good functioning order.
  • The silt removed from septic Tank is a hazardous material and disposal of that is in itself a problem.
  • Capacity to manage sewer is limited and so not recommended for big buildings
Third option available is soak pit. This system is in use since many years successfully in most rural areas and even in the city in most gaothan areas, this system has been in use since the early times. In this system, working is very simple. It is based on nature's power to destroy pathogen by the power of microbes such as actynomycitis, many fungi and other innumerable microbe. The system is the most economical and needs least after care. A tank like structure is made at the ground level with its top slightly above ground level. This structure has all its four sides made of proper walling. Its bottom is left open to ground. This structure is called Soak Pit. Top is having one or two manholes in case any inspection is needed. The system functions very naturally. Stool with its accompanying water enter into the soak pit. It is dumped in the Soak pit and it lands at the bottom right on the ground below. Immediately, microbes in the ground gradually begin to consume the potent material such as proteins, starch, sugars and fatty acids along with the pathogen if any. Within 3 to 4 days, this waste is converted in to black soil. Our ambient temperature is around 30 degrees Celsius; this helps expedite this process of destroying human waste early. Water accompanying the stool and other water from other uses also comes in the soak pit and eventually, absorbed into the ground.
Water accompanying stool is having B.O.D. value of around 200. It is oxidized by oxygen from the air in the pit as well as in the ground. Experimental tests have shown that at distance of around 60 feet and more this value comes to 20 B.O.D. whereas, water of the order of 50 B.O.D. is allowed for drinking purpose as well as cooking. This adequately shows that this water from the soak pit also helps recharge water to keep water table at required level.
Given here are some advantages of having soak pit
  • Minimum cost to build it.
  • Maintenance cost is negligible.
  • Helps recharge water in ground.
  • All disadvantages due to Drainage system and Septic Tank are eliminated.
  • Very environment friendly System it is.
  • BMC or government has no any expense. All cost is born by Builder of the premises.

This paper is sent to our CM Devendra Phadnavis for further action to resolve our health problem. 
Below given is schematic view of Soak pit.
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