Evaluation of Tannery Wastewater Treatment by Integrating Vesicular Basalt With Local Plant Species in a Constructed Wetland System

Abstract

Tannery wastewater is composed of a complex mixture of organic and inorganic components from various processes that can critically pollute the environment, especially water bodies if discharged without treatment. In this study, integrated vesicular basalt rock and local plant species were used to establish a horizontal subsurface flow constructed wetland system and to investigate the treatment efficiency of tannery wastewater. Four pilot units were vegetated with P. purpureum, T. domingensis, C. latifolius, and E. pyramidalis, and a fifth unit was left unvegetated (control). The constructed wetland units in horizontal subsurface flow systems were effective in removing total chromium (Cr), chemical oxygen demand (COD), and 5-day biological oxygen demand (BOD5) from the inflow tannery wastewater. The removal efficiency reached up to 99.38, 84.03, and 80.32% for total Cr, COD, and BOD5, respectively, in 6 days of hydraulic retention time (HRT). The removal efficiency of total suspended solid (TSS), total phosphorus (TP), and nitrate (NO3−) of the constructed wetland units reached a maximum of 70.59, 62.32, and 71.23%, respectively. This integrated system was effective for treating tannery wastewater, which is below the Ethiopian surface water standard discharge limit set to BOD5 (200 mg L−1), COD (500 mg L−1), total Cr (2 mg L−1), NO3− (20 mg L−1), TSS (50 mg L−1), and TP (10 mg L−1).

Improving Tannery Wastewater Treatments Using an Additional Microbial Treatment with a Bacterial–Fungal Consortium

“…These advanced techniques are efficient in removing Cr, while adsorption techniques have also shown their efficiency. Inorganic adsorbents in combination with local plant species in constructed wetland have been found to remove tannery pollutants efficiently [16]. Organic adsorbents such as waste tea leaves have also been presented as an efficient, economic, and environmentally sustainable adsorbent of Cr and other heavy metals in tannery wastewaters [17].…”

Bio‐purification of domestic wastewater through constructed wetland planted with Paspalidium flavidum

“…Among, various other wastewater treatment technologies, the constructed wetland technology is believed to be a cheap and eco-friendly alternative with some pronounced merits of having less operation and maintenance cost; help support wildlife habitat as well as utilization of green plants not only increases esthetic value of wastewater treatment system but also provides sustainable, solar-driven approach for wastewater treatment; therefore, it is gaining more attention of scientific community (Das et al, 2014;Kumar & Chopra, 2018;Sehar, Naz, Das, & Ahmed, 2016;Sehar, Naz, Khan, et al, 2016;Vymazal & Březinov a, 2015). Constructed wetlands are effectively utilized worldwide for the treatment of various types of wastewater types such as domestic wastewater (Fu et al, 2018;Sehar et al, 2013Sehar et al, , 2015Sehar & Naz, 2017), industrial wastewater (Kaushal et al, 2018;Saeed et al, 2018), food processing (Kiliç et al, 2013;Paing et al, 2015;Sehar, 2020), fertilizer and chemical manufacturing (Licata et al, 2019;Maine et al, 2019), tannery wastewater (Alemu et al, 2021;Saeed et al, 2012), paper mill effluent (Lin et al, 2018;Singh et al, 2021), and for the elimination of emerging organic contaminants (Hijosa-Valsero et al, 2010). A wide variety of natural materials and synthetic products such as sand, crushed stones, organic clay, slag, soils, gravels, vermiculite, limestone, coal slag, woodchips, dolomite, wollastonite, lightweight aggregates, marble, Zeolite and Bauxite, fly ash, biochar, bentonite, and activated carbon can be used as substrate or fill media in CWs that provide additional absorption sites (Mateus & Pinho, 2020;Sehar et al, 2013;Wang et al, 2020;Yan & Xu, 2014;Yuan et al, 2020;Zhou et al, 2017).…”