Removal of ammonia from tannery effluents in a reed bed constructed wetland

Abstract

A horizontal subsurface flow reed bed, Pragmites australis, constructed wetland system was operated continuously for one year at 5 different hydraulic retention times between 5 days-11 days with real tannery industry effluent to investigate mainly NH4-N and COD removal performance of the system. The bed was also operated at different initial NH4-N concentrations between 10–30 mg/L by adding NH4Cl into the tannery effluent. The results indicated that ammonia-nitrogen removal is significantly affected by hydraulic retention time while COD is not. The optimum HRT was determined as 8 days with over 95% NH4-N and around 30% COD removal efficiency. The system shows higher removal performance at high initial NH4-N concentrations. Almost complete (99%) NH4-N removal and over 40% COD removal was obtained at (NH4-N)0 = 20 mg/L and HRT = 7 days. PO4-P and total chromium removal were not significantly affected by operating conditions

Constructed wetland systems vegetated with different plants applied to the treatment of tannery wastewater

“…The former plants supported different hydraulic conditions. The potential of using P. australis and T. latifolia in CWs is found in literature in several studies dealing with domestic and industrial-tannery, dye-rich wastewater, food processing and high-strength winery-wastewater treatment (Vymazal, 2005;Vymazal and Kr + opfelová , 2005;Mbuligwe, 2005;Kucuk et al, 2003;Shepherd et al, 2001;Vrhovšek et al, 1996). Vymazal (2005) also reported the successful use of Iris spp.…”

“…However, no detailed information is provided on the hydraulic loadings applied to the systems. In contrast with these high removal efficiencies, Kucuk et al (2003) reported a maximum COD removal of 30% for a tannery wastewater with an inlet concentration of 300 mg L À1 , using a hydraulic retention time of 8 days. It is thus clear that the specificity of the different tannery wastewaters affect their biodegradability in a CW.…”

“…The effluent treatment systems for the tannery industry experience frequent problems due to the fact that they are often working over the capacity due to poor design, or to increases in production. In these situations, a CW can be potentially used to enhance the overall biological performance (Daniels, 2001b), or can be an alternative to the conventional biological treatment (Daniels, 2001a;Kucuk et al, 2003). However, no detailed studies on the treatment of tannery wastewater using CWs are known in the literature.…”

Fitorremediación de aguas residuales industriales mediante humedales artificiales para uso agrícola

“…Los principales mecanismos para la eliminación del fósforo en los humedales son la adsorción en el sustrato y la precipitación química con calcio, hierro, aluminio o materia orgánica [16]. Algunos autores observaron reducciones en los contenidos de Cr en las aguas residuales tratadas en humedales artificiales con P. australis [17]. Varios estudios han demostrado que los humedales tienen un potencial considerable para eliminar B de las aguas residuales y se ha demostrado que las plantas y los sustratos tienen una fuerte capacidad de eliminación de B del agua contaminada [18].…”

Performance of pilot-scale constructed wetlands for secondary treatment of chromium-bearing tannery wastewaters

“…Horizontal, subsurface flow constructed wetlands have the potential of addressing this challenge. In fact, wetlands have been successfully applied in trial studies to polish the effluents from conventional wastewater treatment plants [8,9], polish wet blue effluents [10,11], and treat wastewaters with high chromium contents [12][13][14]. However, their performance in terms of reliability and resilience when used as the sole secondary treatment process of a complete tannery operation has yet to be assessed.…”