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Acid Recovery System for pickling wastewater
February 6, 2010
DEAR SIR, GREETINGS,
WE ARE AN ASSOCIATION OF INDUSTRIES. WE HAVE INSTALLED A COMMON EFFLUENT TREATMENT PLANT (PHYSIO-CHEMICAL TREATMENT PROCESS- S/G+PC+DMF+GAC+CI 2). MAJORITY OF WASTE WATER DISCHARGE IS FROM STAINLESS STEEL COLD ROLLING INDUSTRY, WHICH ARE DURING THE MANUFACTURING PROCESS OF THE S S SHEETS HAVE TO ACID PICKLE THE SHEETS WITH A PICKLE BATH OF HYDROFLUORIC ACID (HF), NITRIC ACID
(HNO3), sulfurIC ACID H2SO4. THE INLET QUALITY OF WASTE WATER GENERATED BY THESE UNITS IS:
SL. NO. | PARAMETERS | VALUES IN MG/L (EXCEPT PH) |
1 | PH | 1-1.8 |
2 | TEMPERATURE OC | 29 |
3 | OIL & GREASE | - |
4 | PHENOLIC COMPOUNDS (AS C6H5OH) MG/L | 28.72 |
5 | AMMONICAL NITROGEN (AS N) | - |
6 | CYANIDE (AS CN) | ND |
7 | HEXAVALENT CHROMIUM (AS CR+6) | - |
8 | TOTAL CHROMIUM (AS CR) | 9.3 |
9 | COPPER (AS CU) | - |
10 | LEAD (AS PB) | 12.95 |
11 | NICKEL (AS NI) | 12.06 |
12 | ZINC (AS ZN) | 1.11 |
13 | ARSENIC (AS AS) | 0.20 |
14 | MERCURY (AS HG) | 0.04 |
15 | CADMIUM (AS CD) | 0.12 |
16 | SELENIUM (AS SE) | - |
17 | FLUORIDE (AS F) | - |
18 | BORON (AS B) | - |
19 | ALPHA EMITTERS, HC/ML | - |
20 | BETA EMITTERS, HC/ML | - |
21 | SUSPENDED SOLIDS | 79 |
22 | DISSOLVED SOLIDS (INORGANIC) | 3892 |
23 | TOTAL RESIDUAL CHLORINE | - |
24 | TOTAL KJELDAHI NITROGEN (AS N) | 45.20 |
25 | COD, MG/L | - |
26 | PERCENT SODIUM | - |
27 | CHLORIDE (AS CL) MG/L | 860 |
28 | SULPHATE (AS SO4), MG/L | 2080 |
29 | sulfide (AS S), MG/L | ND |
30 | PESTICIDES | - |
31 | BOD5 20OC | 27 (BOD3 27OC) |
32 | CONDUCTIVITY, MS/CM | 5.23 |
33 | NITRATES, MG/L | 8.50 |
34 | NITRITES, MG/L | 0.08 |
35 | PHOSPHATES, MG/L | 4 |
36 | TOC, MG/L | 52 |
37 | IRON | 368.7 |
38 | Manganese | 49.3 |
39 | ALKALINITY (AS CACO3), MG/L | - |
ALTHOUGH THE RESULTS OF TREATED EFFLUENT ARE WELL WITHIN THE PRESCRIBED LIMITS BUT MAIN PROBLEM IS OF GENERATION OF HIGH QUANTITY OF SLUDGE AND THE ACIDIC WATER IS DAMAGING THE INFRASTRUCTURE/ EQUIPMENTS.
SL. NO | PARAMETER | EPA STANDARDS | RESULTS OF TREATED EFFLUENT |
1 | PH | 5.5-9.0 | 7.1 |
2 | TSS | 100 | 46 |
3 | COD | 250 | 96 |
4 | BOD | 30 | 27 |
5 | NI | 3 | 0.84 |
6 | CU | 3 | 0.92 |
7 | ZN | 5 | 0.84 |
8 | CR | 2 | 1.38 |
9 | CR +6 |
| ND |
10 | PB | 0.1 | 0.06 |
11 | TRC | 1 | ND |
12 | CI | 1000 | 900 |
13 | SO4 | 1000 | 155.8 |
14 | CD | 1 | 0.84 |
15 | O&G | 10 | 2 |
16 | TDS | 2100 | 4960 |
17 | PHENOLIC COMPOUNDS | 1 | - |
18 | AMMONICAL NITROGEN AS N | 50 | 2.7 |
19 | CYANIDE AS CN | 0.2 | - |
20 | FLUORIDE | 2 | 2.4 |
21 | sulfide | 2.8 | 1.8 |
WE ARE LOOKING FOR A SOLUTION TO OUR WASTER WATER FOR RECOVERY OF ACID TO AVOID EXCESS LOAD ON OUR CETP AS WELL AS TO SAFEGUARD OUR SYSTEM. ARE SUCH SYSTEM AVAILABLE OR THEY ARE JUST RUMORS IN THE MARKET ABOUT THEIR AVAILABILITY.
THANKS IN ADVANCE AND BEST REGARDS,
LEGEND:
S SCREEN CHAMBER
G GRIT CHAMBER
CI 1 PRE CHLORINATION
CI 2 POST CHLORINATION
PC PHYSICO CHEMICAL
PSF PRESSURE SAND FILTER
DMF DUAL MEDIA FILTER (SAND & FLY ASH)
GAC GAC - GRANULAR ACTIVATED CARBON COLUMN
EA EA - EXTENDED AERATION TANK
SST SST - SECONDARY SETTLING TANK
general secretary of confederation and actual user. - Delhi, India
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