Textile Effluent dark color reduced by dosing the 40 ppm Chlorine gas and 50% cod reduced it is advisable to treat with chlorine gas for reduction of color and cod value,Raw effluent COD Value 1200 ppm .By dosing 40 ppm chlorine gas it will reduce 600 ppm ,After that it goes in Aeration Tank but in aeration COD Value does not reduced ,at the inlet of aeration tank Chlorine is nil,
Dear Rajeev,
Any Oxidizing chemical reduces the COD from wastewater/ or a solution, be it Cl2 or H2O2 or chromate or oxygen.
In your case situation is little different when you dosed Chlorine gas in the wastewater it oxidised organic & inorganic part of dye reducing both BOD(biodegradable part of polluent) &some COD (chemically oxidizable part of pollutants ) and leaving some COD unoxidised (600 ppm) in treated wastewater,As this COD could not be consumed by microbes in aeration zone(mostly chemically oxidizable part of pollutants ) thus treatment by Aeration did not reduced the COD.
you are requested to check BOD to COD ratio at inlet and outlet of gas treatment zone. probably you need to increase the dosing of gas.
Another better way to reduce the consumption of gas use aeration after pretreatment and then use gas or H2O2(I personally prefer Fantom reagent) to reduce the remaining COD.
I hope this would help you
thanks & regards
Dinkar
I would suggest to concentrate on oxidising agents which do not further contribute to the overall effluent laod by toxic substances. For this the use of chromate or chlorine should not be taken into consideration. First chromate is toxic and carcinogenic and therefore not easy to handle and the resulting trivalent chromium species are toxic to aquatic environments. With chlorine you a generating and discharging AOX (adsorbable organic halides) which are also often restricted by legislation. Treatment with H2O2 or ozone will be a good alternative.
Dear Rajeev
The existing pollution level of the water bodies from the textile wastewater will be significantly reduced by using chlorine and compounds of chlorine. It act as an oxidising agents but to remove COD treatment with H2O2 will be a good alternative.
Ozonisation of waste waters is established, e.g. to purify urban waste waters. Therefore also O3-treatment will be a good option.
Yes once Cl2 dosed prior to aeration expected to cause reduction in COD. However better option may be use of some high CEC absorbent in place of chlorine.
Thanks
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