We need to implement a compact waste water treatment plant for a tannery.
It needs to have low CAPEX and OPEX and the treated effluent should meet the standards of pretreated sewage to be discharged into the municipal sewage network.
How do I remove chrome and other residues of the industrial process of tanneries?
I will appreciate any information and experiences with designing such a plant and treatment technologies.
We offer engineered systems for tannery Wastewater streams including chrome recovery and reuse with low Capex and Opex. Please provide me your contact information for more details.
I have done some work with tanneries and have found that an effective way to treat these difficult waste waters is with a series of solid/liquid separation steps and then electrocoagulation and separation again. This deals with your harmful Chrome elements and generally brings the discharge within specification.
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by Wayne Pozarycki, ZBiG Consult - Managing Director
Tanneries and several textile finishing sites have quite high water consumption and use primarly non or slowly degradable agents and auxiliaries. Tanneries use also toxic Sulfides, making Things more complicated. Chromium can be today replaced by less harmful tanning agents. Biotreatment has the lowest costs, but can´t achieve a complete treatment, so that oxidation methods are necessary for a better removal.
Thank you for proposing this question to the group. Is this for an existing facility or a new facility? We have experience with working with two North American Cattle Tanneries and One Tannery in India. As part of your process are you chemically burning the hair off the hide or are you scrapping the hair first then using chemistry to finish the process?
The faculties that we have worked with have suggested removing the solids first then treat for the Chrome. (Coarse Screening 1" followed by fine screening 200 micron). This process will remove the hide hair and tallow. Case study attached.
If you would like to discuss greater details please email me at
Chromium can be removed through innovative ion exchange adsorption technology using natural adsorbents such as low cost vermiculite through fixed bed filtration.
Carlos, is adsorption really applicable to pre-treatment for sewer disposal? What is the adsorption capacity per kg of adsorbant, and how would it cope with the other contaminants and solids in the effluent? Ion exchange and adsorption is normally used only for final polishing of effluent once most of the contamination has been removed by other, cheaper methods.
At first should you deliberate over a question – will you recycle the chrome and tanning agents from your waste water and use these again for the tanning process or will you only pre-treat your waste water so that you can discharge it to the municipal sewage network. The recycling of chrome and other tanning agents can help you to minimize the costs of the waste water treatment. If you´ll have some information to the technologies what you can use for the recycling process please don´t hesitate to contact me direct.
You are quite right - the first step is to look at options to eliminate or reduce the discharge of chromium by using alternative tanning agents (which may not be possible) and by recycling or reducing wastage within the tannery. THEN look at treating the effluent.
The best approach is generally chemical coagulation and then filtration. If there are significant settleable solids in the effluent, you should include a gravity settlement stage first to reduce the load on the filters. For further information see http://www.sciencedirect.com/science/article/pii/S2212371713000085
Depending upon the coagulation characteristics of the effluent, and on the chromium limit for the receiving sewer, you should design the filtration process to ensure that limits are met reliably. Coarse sand filters are cheapest but will require better coagulation to create large flocs. If you need a fine filter, I can assist you with a design for our patented FilterClear system, which has been used successfully to remove metals from industrial effluents.