Is today’s sewage treatment actually what’s
best for our health…..?
Relating to
our feature lectures looking at sewage and its treatment along with prevalent
microbes that are present and cause severe health problems this paper was
relevant as it looked at whether sewage microflora could be used as a potential
indicator for effective water sewage treatment or whether the methods
undertaken at present are not effective enough.
The study by
Maruthi et al (2013) aimed to see
whether the sewage treatment in Vishakhapatnam is effective as it could and
should be, although this does not relate to things closer to home it does
provide an insight into whether the treatment in the UK is effective enough and
provides a potential method of what could be done here to test the
efficiencies.
Environmental
surveys are necessary to understand and document the occurrence and distribution
of bacteria that could cause negative effects within any population, not just
the human one. Numerous studies looking at this microflora and this has only
increased since sewage has been classed as an emergent pollutant as they are
commonly found in watercourses. The city
in question, is a city situated on the coast of the Bay of Bengal and currently
has an unscrupulous amount of sewage daily, these figures average about 330
million litres per day of sewage, and of this only 25mld are treated, hence the
need for a study like this and a massive increase in treatment protocols.
The method
undertaken involved 10 sites that were previously selected from along the coast
of this city, at sewage exit points, these water samples were then transported
back to the laboratory for further testing. The microflora that was being
looked at were selected prior to this, and compiled in a table within this
paper. The key measurements recorded were the total coliform count, the total
bacterial count and also the total salmonella count. These were not the only
measurements undertaken as bacterial fungal counts were also taken of select
species and the same for a select group of Helminthes (Family of parasitic
worms).
The results
found that even after sewage treatment a large abundance of animal and fecal
related coliforms were still present after the treatment which in this case is
chlorination, the general range of microflora was quite large and this depended
on the area taken from but overall the fact that there is still a significant amount
of these organisms present is alarming. So this study has demonstrated the fact
that chlorination cannot provide the complete answer to treatment and should be
used in accordance with another, If not a few more processes. Yes this study
looked just at one city but the general principle and results can be applied
globally. So this needs to be addressed and I still found this paper both
relateable and interesting.
Any
questions please ask.
Ollie.
Available
at:
Reference:
Maruthi,Y., Hossain,K., Rao,S. and Kumar,Y. (2013). Sewage Microflora
is a potential indicator of effective sewage treatment. The Ecoscan, Volume III,
35-39.
Hi Ollie
ReplyDeleteInteresting topic, and we think our policies are bad...
Did the study actually compare the treated to the non-treated sewage water, because it seems to me that the samples collected from the various sites represent a mixture of both, so you wouldn't be likely to detect any effects of the chlorination treatment? Since only ca. 7.6% of sewage water is actually treated via chlorination, you would probably expect high levels of sewage microflora to be still present.
Also, did the authors discuss the usefulness/precision of a particular indicator species/group? As was pointed out in previous lectures, the use of indicator groups does not come without some major caveats...
thank you
Anna
hey anna, thanks for the comment.
ReplyDeleteit just says they selected them from points along the way, and for some reason only W11 in the results section is from a treatment plant, obviously they wanted to do some recce as to which area produced the worst so they could tackle them first and did the treatment ones as somewhat of a control to use in comparison and see if they were doing the right thing.
overall it does appear to be a fairly biased study towards showing just pollution levels and not as you say demonstrating the chlorination effects but yeah.
as for your second question;
they mentioned a few specific species but there wasnt a resounding one that was applicable all round so to speak if that makes sense, overall it was a useful starting point but as i saw and u have pointed out it has its flaws.
Hi Ollie,
ReplyDeleteI was wondering if the paper identified the coliforms that were present after treatment by chlorination? This would particularly interesting considering the function of the microbes in terms of human health (and of course the environment) depends on the specific organism.
Also, although a large quantity of indicators of pathogenic organisms were present (coliforms), the pathogenic organisms themselves could have be killed by the treatment, even if these indicators were not. I was wondering if you know anything about how these indicators work in terms of their presence being dependant on pathogens, and if it is possible for them to remain once the pathogens have been removed?
Thanks,
Megan
hey megan good lord i apologise this comment return has taken so long i didnt notice i had a new comment.
ReplyDeleteIn answer to your question, the one key coliform they mentioned was Salmonella shigella and Ascaris lumbricoides as evidently these cause wide problems, they mention penicillium and such but these were not prevalent after severe treatments.
And i think i get what you're asking so please correct me if im answering a completely wrong question, i assume as these indicators are usually negative that they are present in similar numbers to the pathogenic organisms and are removed in the same sort of percentage as the pathogens, as the treatment is very vague and unsuccessful in this case i believe everything is present in high numbers and therefore they have been removed too, im sure there are cases of indicators that remain just as there will be pathogens that remain but i assume its an occurence that cannot be predicted, by this i mean that you cant really see what will be removed or will remain under individual conditions.. as everything varies.
I hope and think this makes sense.
cheers
Ollie.