An example from my personal experience: At Consett Coke Ovens one of the
waste streams was phenolic liquor. Once-upon-a-time it would have been dumped
down a disused mineshaft! We treated it in an activated sludge plant (loads of
bacteria). Pretty amazing that it worked at all considering that the old name
for phenol is carbolic acid and it’s a disinfectant which kills just about
anything. We had a “spike” in phenol concentration (the plant was old, some of
the processes had problems and the control systems were partly f*cked). As a
consequence the bacteria “went to sleep”. They weren’t actually dead, but they
weren’t active. As a consequence, even after the phenol levels returned to
normal, the activated sludge plant no longer worked. We couldn’t treat the
phenolic liquor, we weren’t allowed to dump it and we had only limited storage
capacity. In these circumstances the official solution was to get a tanker load
of sludge full of adapted bacteria from another coke plant. The nearest one
with a suitable plant was in Sheffield (probably Orgreave). Cost at the time –
several hundred quid. We chose the cheapskate option: buy a lorry-load of
steaming, fermenting farm-yard manure and dump it in the sludge tank. Cost – 50
quid. After a short time (not more than weeks, and within the limits of the
buffer storage capacity) the activated sludge plant was back and operating to
specification. BTW on that plant they described having too much liquor as being
“embarrassed” – as in “an embarrassment of riches”. A nice turn of phrase, with
a touch of irony - “an embarrassment of sh1te”.
I doubt there are bacteria in nature which actively use phenol as a food
source. Thankfully there isn’t enough of it around. There are undoubtedly
bacteria which can tolerate phenol up to a certain concentration. The moral of
the tale is that given the opportunity, within a very short time, bacteria can
adapt to use something which is an outright poison to them (phenol) and not
simply tolerate it, but use it as a food source. How they do it is not clear to
me, but they certainly do. That is amazing and scary! The rubbish-dump
programme was another example of the same.
