Presentation at IX World Aqua Congress WAC-IC 2015 IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel Page 1 of 14 Proposed Title IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT Full Name of Author : PRABHASH GOKARN, Head (Engineering Projects & Town), Tata Steel Full Name of Co-Author 1 : PANKAJ SATIJA, General Manager(Operations), FAM, Tata Steel Full Name of Co-Author 2 : ARIJIT MONDAL, Manager(Projects & Construction), FAM, Tata Steel Full contact address of corresponding author : Prabhash Gokarn Head (Engineering Projects & Town) Ferro Alloys & Mineral Division Tata Steel Limited Administrative Building | Sukinda Chromite Mine | PO Kalarangiatta | Jajpur | Odisha 755028 Mobile : +91 - 77 5200 4399 e mail : [email protected][email protected]Identification of the Congress theme most closely related to the paper Water Quality & Treatment Techniques & Practices Five keywords of the paper Effluent Chromium +6 Water-treatment Technology Construction Category of their presentation format : Oral
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Presentation at IX World Aqua Congress WAC-IC 2015
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel
Page 1 of 14
Proposed Title
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Full Name of Author : PRABHASH GOKARN, Head (Engineering Projects & Town), Tata Steel Full Name of Co-Author 1 : PANKAJ SATIJA, General Manager(Operations), FAM, Tata Steel Full Name of Co-Author 2 : ARIJIT MONDAL, Manager(Projects & Construction), FAM, Tata Steel Full contact address of corresponding author :
Prabhash Gokarn Head (Engineering Projects & Town) Ferro Alloys & Mineral Division Tata Steel Limited Administrative Building | Sukinda Chromite Mine | PO Kalarangiatta | Jajpur | Odisha 755028 Mobile : +91 - 77 5200 4399 e mail : [email protected][email protected]
Identification of the Congress theme most closely related to the paper
Water Quality & Treatment Techniques & Practices
Five keywords of the paper
Effluent Chromium+6
Water-treatment Technology Construction
Category of their presentation format : Oral
Presentation at IX World Aqua Congress WAC-IC 2015
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel
Page 2 of 14
Title
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT
TREATMENT PLANT
ABSTRACT
Tata Steel operates chromite mines at the Sukinda Valley in Odisha producing chrome ore which is subsequently
converted it to Ferro Chrome and sold to customers across the world. A large quantity of water, pumped out from the
mining pit and due to rainfall, needs to be handled during the mining operations. Chrome Ore mainly contains tri-valent
Chromic oxide and a very small fraction of hexavalent di-chromate. Water coming in contact with chromium ore
preferentially leaches out soluble hexavalent chromium from the ore body, as a result, water from the mine contains 0.2 –
4 mg/l of hexavalent chromium against a safe limit of 0.005 mg/l for human consumption; requiring all water to be treated
before its release from the mines. Thus, Tata Steel is setting up an additional state of art effluent treatment plant at
Sukinda with a capacity of 108 million litres / day; one of the largest in the region; which will be completed by Sept 2015.
This paper discusses how the technology for the Effluent Treatment Plant was chosen amongst various alternatives, how
the capacity of the plant was decided, the challenges during construction of the said Effluent Treatment Plant that were
faced, and how these were successfully tackled. The paper also describes how, because the outlet water is of a better
quality than the water from the local water body, the outlet water will be used as the input to the Water Treatment Plant,
aiding water consumption and lowering operating cost.
Presentation at IX World Aqua Congress WAC-IC 2015
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel
Page 3 of 14
Title
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT
TREATMENT PLANT
INTRODUCTION
Describing Sukinda and importance to FAM
Sukinda Valley, in Odisha is known for its high grade chromite deposits. The deposit was first proved by geologists of
Tata Steel in 1949. TSL’s Sukinda Chromite Mines is the one of the largest chrome mines in India enabling Tata Steel to
be one of the larger chrome alloy players in India.
Chrome Ore
Chrome ore occurs as Chromite, which is chromium oxide, and as friable or lumpy rocks(Fig-1). Chromite contains mainly
stable trivalent oxide of Chromium with a small fraction in the unstable hexavalent state.
compounds - Reduces residence time in the Clariflocculator,
while enabling control of TSS within statutory limits
This has increased the throughput of the ETP and enables treatment of a large volume of water in a short time
i. Acid Dozing of the raw effluent in a flash mixer to bring down the pH before reaction with FeSO4 since the FeSO4 reaction is most efficient at a low pH. Also, because of the efficient reaction at low pH, the consumption of FeSO4 and the amount of sludge generated is substantially reduced.
ii. Stirring arrangement in the flash mixer and a
reaction channel to allow for complete reduction of hexavalent chromium.
iii. pH correction using an alkali before dozing
with a polyelectrolyte, to ensure complete reaction, as polyelectrolyte reaction needs a neutral pH, along with a stirring arrangement.
These facilities have not been installed by other players
Design Elements Online Monitoring & Automation
The Effluent Treatment Plant is so designed that: - the output not only meets current specifications
for treated effluents in non-urbanized areas, but in order to be future ready, meet the specifications for treated effluents in both urban areas and the likely stricter norms for treated effluent that are likely to be imposed in the future.
- the plant has been designed such that the
output has less than 0.01 mg/l of Cr+6 against a norm of 0.05 mg/l and meets the stricter TSS standard of < 10mg/l (drinking water specifications) against a norm of < 100 mg/l (norms for treated effluents in non-urbanized areas)
- treat both surface run off water and mine water
in same way, which none of the other mines in Sukinda planned to do
The ETP has state of art online monitoring & automation systems :
a. 24/7 real-time monitoring of the input raw effluent and output treated water for Cr+6, pH and TSS through online monitors installed at both input (raw effluent) and output (treated water) to prevent any inadequately treated effluent from leaving the mine and give warning signals if the treated output water quality is not up to the mark.
b. The ETP is highly automated, with a
feedback mechanism. Thus the dozing of chemicals (acid, FeSO4, alkali, and flocculants) is automated through a system of PLC based controllers, based on the input raw effluent and the output water quality.
c. Automated backwash arrangements for the
pressure sand filters to ensure that the filters do not choke.
Table – 4 : Unique Features of the Effluent Treatment Plant at Tata Steel Sukinda Chromite Mines
Real Time Monitoring of Data
For real-time monitoring of data, we have set up a data communication system that captures real-time information from
the analysers for Cr+6
, TSS and pH installed at the outlet in a server and transmit the data thus captured automatically to
OPCB/ CPCB server on real time basis. The schematic of data transmission is shown in Fig-5 and the output screen in
Fig-6.
Presentation at IX World Aqua Congress WAC-IC 2015
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel
Page 12 of 14
Fig - 5 : Schematic Diagram of Capturing & Transmitting Data for Real Time Monitoring
Fig - 6 : Result of Online Monitoring of Treated Effluent - the effluent is well within the specified limits
Presentation at IX World Aqua Congress WAC-IC 2015
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel
Page 13 of 14
Thus the output water quality data are available both internally through a dedicated web page and can be transmitted to
the Pollution Control Board on a real time basis.
A photograph of the Effluent Treatment Plant is shown in Fig-7.
Fig - 7 : The Effluent Treatment Plant (View of Clariflocculator #1)
CONCLUSIONS
The success of the ETP Project can be summarized to be as a result of the following :
i. Vendor selection only after an intense technical evaluation of the capability of the vendor and not on commercial
considerations alone.
ii. A strict focus on time lines and cost at all levels with frequent high level reviews and support to the project team
iii. Over-riding concerns of safety and quality with mechanisms for frequent checks (preferably external to project
team)
iv. Deep understanding and cooperation between all agencies working on the project, which developed during the
course of the execution and was necessary to cope up with unforeseen challenges that can crop up at any time :
and need to be resolved collaboratively.
Presentation at IX World Aqua Congress WAC-IC 2015
IMPROVING WATER QUALITY BY CONSTRUCTING AN EFFLUENT TREATMENT PLANT
Prabhash Gokarn*, Pankaj Satija and Arijit Mondal, FA&MD, Tata Steel
Page 14 of 14
WAY FORWARD
The output water quality post treatment at the Effluent Treatment Plant is better than the water available in the local
Nullah, giving us the opportunity to use it as an input for our Water Treatment Plant(WTP) and in various other places, like
dust suppression, gardening etc.(Fig-8). The benefits of this are:
a. Good Quality Water: During the monsoon season water flowing through Domsala river has very high TSS. The
output water from the ETP is already treated and thus a better input to the WTP than the water from the Nallah.
b. Cost Saving : Apart from substantial cost saving in pumping from the Nallah which is over 3 km away, the chemical
consumption at the WTP will substantially reduce, due to the consistent and better input water quality, reducing the
cost of treatment as well.
c. Towards Zero Discharge : As per the Pollution Control Act, an industry should ideally have ZERO discharge. Thus
reusing the water from the ETP is one step towards achieving zero discharge.
Fig - 8 : Schematic Diagram of our plan to use the ETP discharge as an input to our WTP
References
1. Rama Murthy Y (Dr) et.al, IFA/ABP/389/2013, Development of Process for Water Treatment at Chrome Ore
Beneficiation Plant, Sukinda, Jun-14.
2. Kapure, Gajanan et.al., Application of Terminalia Chebula for Removal of Hexavalent. ISIJ International, Vol. 48.
2008.
3. Internal Report on Water Quality & Runoff Management at Sukinda Chromite Mine, 2012.