St. Martha’s Hospital in the heart of Bangalore has been treating patients for over 128 years now, and sees a traffic of two and a half lakh outpatients and 21,000 in-patients a year. As a hospital, it is no real surprise that they release a daily volume of waste water of about 300 KLD (kilolitres per day). Taking care of this can be an ordeal, as apart from the sheer scale of the operation required, also considering that the nature of the waste released by hospitals (wet, dry and bio-medical) is more complex than a regular bulk generator.
The setup here however not only manages this with a startling accomplishment of 100% water reuse, but proves to have medium to long term economic benefits as well. We shot a few questions at Tharun Kumar of Paradigm Environmental Strategies to find out a bit more about this local success story.
St. Martha’s is a 128 year old hospital in Bangalore run by the Good Shepherd’s Convent. Pic courtesy: Hari Nadig
How did the St. Martha’s project come about?
TK: Around five years ago, the KSPCB (Karnataka State Pollution Control Board) started going after Hospitals to ensure that they implement the requirement to use STPs (Sewage Treatment Plants). A number of hospitals had basic STPs, some had septic tanks (which fill up and need to be cleared out regularly), while most of them simply disposed off their waste into the drainage system. When St. Martha’s Hospital opted to use an STP in 2009, they had a couple of options: a conventional STP based on aerobic bacteria which would operate as a perpetual motor requiring fuel, or the system we use, based on anaerobic bacteria, which while not being a very popular option at the time, would prove to be the better long term economical choice as well as one that would enhance their reputation as a sustainable hospital.
How it the setup used in St. Martha’s different from the regular ones?
TK: Our process is similar to what would take place inside a septic tank, or even a cow’s stomach for that matter. All we did was apply this process to get predictable and desirable results. The benefits to be gained from the use of this process are clear, both in terms of the output of the reusable water as well as the ancillary costs involved in the maintenance of the system.
Then why is it that aerobic processes continue to be the mainstay of water treatment mechanisms?
TK: The fact is that processes involving aerobic bacteria are ones which have a significant amount of research going on, and are widely advocated the world over. This could well be due to the fact that tropical conditions are most conducive to anaerobic processes, and most of the popular opinion in this field comes from places with colder climate. This trend is easily demonstrated with even a simple Google search on these processes, which throws up a lot more material for aerobic mechanisms than for the anaerobic kind. The use of the large machinery in aerobic processes holds significant benefits in terms of profits for hardware companies as well as opportunities for kickbacks to regulatory officials. So you can see the reasons people might have for not promoting anaerobic mechanisms.
Conventional STP options
Why do institutions go for waste water treatment?
TK: There are a number of factors. Chief among them being the Urban Reuse Standards as laid down by the KSPCB (Stipulations regarding the contents of water treated by STPs). Some organizations find it critical to their reputation to be sustainable enterprises and to follow the best practices in waste management. Others simply want to take care of any kind of procedural headaches in a way that they don’t have to worry about later.
Is the mechanism viable?
TK: Water recycling can prove to be economical in two ways – firstly, the cost of running an anaerobic STP is roughly one-twelfth of the cost borne in the running of a regular aerobic treatment plant. Secondly, there are major savings to be made in water usage as a result of the reusable water that the STP provides you with. In the case of St. Martha’s hospital, the water supply bill was brought down from five lakhs to two and a half lakhs, which is a 50% decrease. The installation of anaerobic STPs in particular can be even more economical as it decreases the costs involved in heavy motors and mostly involves civil installation works.
What are the results of the installation at St. Martha’s Hospital?
TK: Our work at the hospital has enabled them to drastically bring down their BOD levels, (Biochemical Oxygen Demand – this is the amount of oxygen required to break down the organic material in a body of water; the lower the value, the cleaner the water) thereby coming within the stipulations laid down by the KSPCB. BOD is the key metric to determine the quality of the water, pre and post-treatment.
Analysis of water in St. Martha’s
What unique challenges does a hospital present?
The older equipment required regular cleaning for its upkeep.
TK: Hospital waste can include chemicals which apart from being harmful in themselves, can also hinder or counteract the bacteria that are used in the water treatment process. The design of the mechanism deals with this problem. Additionally, the kind of by-products formed as sludge from a hospital would tend to be more harmful. The anaerobic STP does help in this regard insofar as it greatly reduces the volume of sludge to be disposed, down to once in two years from about once a month.
How stringent are the standards laid down by the KSPCB regarding treated wastewater?
TK: The Urban Reuse Standards as they are called, are difficult to comply with but not impossible. St. Martha’s hospital is the perfect example of this, additionally having done so as at a low cost. It’s worth noting that the standards can be rather easily complied with if you have a large amount of capital so as to be able to simply purchase an Ultra Filtration STP unit.
It’s great to see this kind of innovation in a field that not only has great scope for such benefits and accessibility to be made possible, but can also help in the long run towards better managed operations in resource management at the grassroot level. Here’s hoping that we do get to sew burgeoning developments with these kinds of possibilities.
Image of St. Martha’s, by Hari Prasad Nadig. CC License https://creativecommons.org/licenses/by-sa/2.0/.
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