We have a technology for producing Chlorine Dioxide Solution using Hydrogen Peroxide as reducing agent. But we produce an effluent stream of about 3.4 m3/ton of ClO2. It contains about 440 pl Sulphuric Acid (H2SO4), 340 gpl Sodium Sulphate (Na2SO4) and 1.8 gpl Sodium Chlorate (NaClO3).
We require a suitable process for handling this effluent and making the process “Zero Liquid Discharge”.
Kindly check and help us in developing that process.
We have an idea of neutralizing this effluent with Lime Solution. But we are not sure about the extent of reaction of Sodium Sulphate (Na2SO4) with Lime Solution.
The quantity of effluent generated is 1.1 m3/hr (for a plant size of 7.5 TPD).
If you want email me anything related to it or helpful for the same..
with Redards
The first point to address seems to be that of avoiding or reducing the sodium chlorate content of the effluent by improving the yield of its upstream conversion to ClO2, as this was the intended product. That could be (possibly) achieved accordingly the following stoichiometry, given favourable conditions: 2NaClO3 + H2SO4 + H2O2 → O2 + 2ClO2 + 2H2O + Na2SO4. Otherwise, another suitable reducing agent could be considered, to economically substitute for H2O2. The hence obtained (modified) acidic effluent could be neutralized with NaOH, to obtain a NaSO4 rich brine, that if not saturated, can be further concentrated, possibly by evaporation. This concentrated brine could be recicled at the Kraft pulping process. Alternatively, from warm Na2SO4 saturated brine (approx. 34ºC) it is possible to recover most of its Na2SO4 content by hereafter refrigerating the brine (≤5 ºC), to crystallize Glauber's salt.
With lime you can precipitate a hydrated calcium sulphate, possibly impure with salt like and bleach like impurities, depending on how much lime is used. The solid or slurry might find use in regional soli conditioners if the several components can be reduced to become compatible with agriculture. Not all regions need this gypsum like soil treatment.
Your process looks something like one used to purify water in areas where organic content prevents the use of chlorine.
It might be possible to put part of this byproduct mix back into the reactor and achieve an equilibrium composition with decreased byproduct, possibly after further treatment.
Calcium byproducts of the carbonate character tend to become insoluble if carbon dioxide is stripped out by boiling or by inert gas.
Zero Liquid Discharge (ZLD) Zero-liquid discharge (ZLD) is a water treatment process in which all wastewater is purified and recycled; therefore, leaving zero discharge at the end of the treatment cycleBusinesses are becoming concerned about water use and pollution reduction. Businesses are inspired by Green initiative and trying to incorporate more environmental friendly approach and technology for the business and manufacturing processes. The objective of ZLD system is to recover and reuse all water and avoid any emissions and wastage of water. The ultimate goal of ZLD systems is to eliminate the discharge or disposal of liquid waste to the feasible extent. ZLD systems try not to discharge wastewater to surface water bodies by recycling, reusing or reducing the volume of waste streams (water based).
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