Study of the Applicability of Chemical Precipitation and Electrocoagulation Method for Chromium Recovery in CETP at Savar Leather Industrial Park

Abstract

When we visited tanneries at Savar Tannery Industrial Estate in order to gain a deeper understanding of the leather tanning industry of Bangladesh, we realized that the lack of environmental compliance certification is holding the industry back from further development. That is why we decided to work on one of the leading concerns, the release of chromium to the environment. We conducted a thorough search for applicable methods, conducted feasibility studies on the selected topics by analyzing the input water conditions and finally calculated the expected method outcome in regard of collected data. We tried to collect up to date information relating to water conditions and cost analysis. We predicted Chemical Precipitation to be at least 99.5% efficient in removing chromium from the wastewater. The efficiency of CP depends on selected coagulant and pH of inlet water. The amount of chromium in outlet water comes within the allowable limit after one treatment. Electrocoagulation on the other hand gives vastly different efficiencies for different electrodes. Whichever electrode we choose; it takes a minimum of two treatments to bring the chromium content within the allowable limit. We found that aluminum and iron both can be used as electrodes in a EC unit at Savar CETP successfully. Our study gives the concerned authority a reference if they choose to add a chromium recovery unit to the existing CETP. It is of great importance that the industry takes necessary steps to ensure environmental compliance and our study might help achieve that. We could not conduct practical experiments due to the pandemic situation. So, we hope others will build on our research and carry out the experiments using the tannery waste water from Savar TIE. Our study 2 indicates that a chromium recovery unit in conjunction to the Savar CETP will be enough eliminate concerns regarding chromium pollution.