Studies of removal of chromium by model constructed wetland

Abstract

-Chromium is a pollutant present in tannery wastewater, its removal is necessary for protection of the environment. Penisetum purpureum, Brancharia decumbens and Phragmites australis were grown hydroponically in experimental gravel beds to determine their potential for the phytoremediation of solutions containing 10 and 20 mg Cr dm . These concentrations, similar to tannery wastewater after initial physicochemical treatment were used with the aim of developing an economic secondary treatment to protect the environment. All the systems achieved removal efficiencies of 97 -99.6% within 24 hours. P. purpureum and B. decumbens removed 78.1% and 68.5% respectively within the first hour. Both P. purpureum and B. decumbens were tolerant of the concentrations of chromium applied, but P. purpureum showed the greatest potential because its faster growth and larger biomass achieved a much greater chromium removal over the whole length of time of the experiment.

Constructed Wetland System as Secondary Treatment for Stabilization Pond Domestic Effluent

“…According to Tables 1 and 2, there were no major changes in pH values in both analyzed areas, regardless of HLR, similar to the studies by Mant et al (2005) and Prochaska et al (2007). This indicates the existence of a buffer system which stabilizes the pH and thereby maintains the processes and chemical reactions in progress (Bastos et al, 2010).…”

“…In the last few decades, environmental pollution has become a public matter in both developed and third world countries. The reason behind such awareness is due to a rapid economic development intensely related to natural resources exploration, which had been previously left untouched (Mant et al, 2005).…”

Biosorption of Cr(III) from aqueous solution using algal biomass spirogyra spp.

“…Cr(III) is selected instead of Cr(VI) because of following facts Cr(III) is toxic if excess quantity is taken and cause abnormalities in organisms. Chromium(III) sulphate salts are mainly used in tanning [6]. Several International Environmental Agencies have introduced strict regulations with regard to metal discharge, especially from industrial activities.…”

Chromium Extraction by Microemulsions in Two- And Three-Phase Systems

“…During the processing of these hides, large amounts of chemicals are used, producing solid and liquid wastes (Mant et al, 2005;Haroun et al, 2007;Lofrano et al, 2013). According to Kiliç et al (2011), tannery sludge contains high levels of chromium, and the disposal of this residue in landfills represents a loss of chromium, a commercially valuable raw material.…”