Soon
automobile servicing industry, food industry, and other low and medium
scale enterprises can have a smart, affordable electric field-assisted
membrane separation device at their disposal for oily waste water
treatment.
Low-income
group users mostly cannot afford the high cost of treatment
technologies available for handling oily wastewater generated at their
source points. As a result, large amount of untreated oily wastewater is
discharged into the aquatic bodies without following the guidelines of
the Pollution Control Board.
The technology developed by Dr
Chiranjib Bhattacharjee, Professor at the Chemical Engineering
Department in Jadavpur University, Kolkata, uses a combination of
Electrocoagulation and Electroflotation Enhanced Membrane Module (ECEFMM) techniques for waste water treatment. Electrocoagulation is a waste water treatment technique
that uses electrical charge for changing the particle surface charge,
allowing suspended matter to form aggregates, and electroflotation
is the separation of suspended particles from water using hydrogen and
oxygen bubbles generated by passing electricity through water.
In
the developed module, electrocoagulation and electrofloatation are
adjoined with membrane in a single indigenous setup. The turbulence
created because of the hydrogen bubbling through the feed medium or the
waste-water resists the deposition of oil over the membrane. The
synergistic effect of hydrogen bubbling and rotation of the membrane
module creates substantial turbulence within the solution and on
membrane surface. On application of electric field during membrane
separation, membrane fouling is substantially reduced, and membrane
longevity is also enhanced by restricting the membrane ageing for
prolonged time period. Thus, it requires less frequent membrane
replacement, thereby reducing the maintenance costs to a great extent.
The
innovation being an economically feasible wastewater treatment
technology (both in terms of capital and recurring investment) for
low-scale and medium enterprises, has a good market potential. Moreover,
unlike other conventional treatment, it can break the highly stable
oil-water emulsion through electric discharge and simultaneously
separates oil from water with high efficiency. Besides, by integrating
the electrochemical process setup with the membrane module in a single
hybrid ECEFMM setup, one process has been eliminated. This significantly
lowers the initial capital investment expense along with the additional
advantage of reduced installation area requirement.
This technology developed with support from the Advanced Manufacturing Technologies programme of the Department of Science & Technology (DST), Government of India requires
minimal manpower and does not need high-end technical adequacy for its
operation, thus reducing the operational expense to a large extent.
The
recovered spent oil after oily wastewater treatment can be further used
as an industrial burner oil, furnace oil, mould oil, hydraulic oil and
so on. Thus, it creates a huge revenue generation scope for low-income
groups by selling this collected spent oil. In a zone of densely
concentrated garages, installation of one setup will serve the purpose
of wastewater treatment and thereby extend the opportunity towards other
low-income group users to control the water pollution level within PCB
regulations. It is aligned with the ‘Make in India’ initiative. The validation
and testing of the prototype have been successfully accomplished, and
the pilot-scale validation and testing is on the verge of completion.
So
far, the separation technology running in different sectors for
treating such oily waste water involves the installation of an
electrolytic cell or DAF followed by membrane unit. However, installing
two separate units requires a high footprint area compared to the
present unit, where two-unit operations are being assimilated in a
single unit, said Dr. Bhattacharjee.
This prototype innovation has proceeded towards level 6 of the Technology Readiness Level, and Dr. Chiranjib Bhattacharjee has partnered with Concepts International for industrial collaboration and scale-up of the innovation. He plans to further carry out a field
run with the pilot-scale module, networking and field installation, and
Commercialization of the equipment through start-up.
Fig. 1: Electrocoagulation and electroflotation enhanced membrane module (ECEFMM)
Fig.
2: (a) Schematic process flow diagram for the operation of ECEFMM; (b)
Schematic diagram for the working principle of ECEFMM; (c): Comparative analysis of variation of normalized permeate flux (NJ) with time at different modes of operation.