Material and Methods
Experimental Design: The experiment has been conducted in
the Environmental Engineering Laboratory of Department of
Civil Engineering, Jadavpur University. The wastewater sample
has been collected from a pharmaceutical industry situated at
Kolkata, India and the municipal wastewater sample has been
collected from KMDA treatment plant situated near Baghajatin
Railway Station.
The pharmaceutical wastewater samples have been tested for
their basic characteristic features. Simultaneously, municipal
wastewater has also been tested for organic carbon and
nutrients.
The pharmaceutical wastewater has been chemically treated
with calcium oxide (CaO) used @ 2g/100ml of raw wastewater.
The wastewater has been stirred thoroughly with the calcium
oxide and then kept overnight only to get precipitate of calcium
oxalate, as the wastewater contains high concentration of oxalic
acid.
Chemically treated wastewater has been decanted after 24 hours
and prepared for anaerobic treatment with 300 ml sludge
(obtained from an anaerobic experimental set up currently
running in the same laboratory) and 200 ml micronutrient
solution in a 5-litre aspirator bottle and kept under 24-hr stirred
condition at around 40˚C for about 1 month. Sampling is done at
3 days regular interval and analysed in the laboratory.
After the anaerobic treatment the treated pharmaceutical
wastewater has been mixed with municipal wastewater in two
sets, one is in the proportion of 1:39 and another is in the
proportion of 1:79 for phytoremediation study. The plant
sample, Pistia stratiotes used for phytoremediation study, has
been collected from Dhakuria Lake, Kolkata. The initial weights
of the plants are 29.26g and 31.31g in first and second set
respectively. The wastewater samples have been collected from
each set at one day interval for study of the variation of different
chemical parameters with time. Side by side control
experiments are also run for each set in order to ascertain the
efficacy of plant system in removing carbon and nutrients.