부산대학교 도서관

Wastewaters from tanneries are characterized by high level of salinity, organic and inorganic matter; sulfur and nitrogenous compounds, chromium, suspended and dissolved solids. The objective of the present study was to develop an innovative biological wastewater treatment system-taking tannery wastewater as a case study-which will produce biogas through anaerobic biogas digestion and will remove nutrients, organic matter and chromium in a sequence batch reactor (SBR) connected to constructed wetlands (CWs): then, the treated wastewater can be reused by the industries and nearby communities. The performance of an anaerobic-SBR, integrated with CW system, was assessed for selected parameters following standard methods. The integrated pilot treatment system showed demonstrable treatment performance of tannery wastewater with overall removal efficiencies of 96.6 % of COD, 90.4 % of TN, 97 % of NH.sub.4-N, 81.8 % of SO.sub.4.sup.2-, 99 % of S.sup.2-, 98.5 % of total Cr, 86 % of EC and 99.9 % of pathogens. Moreover, the anaerobic system is generating biogas at a rate of 26.2 to 36 m.sup.3/day with an average composition of CH.sub.4 (61.3 %), CO.sub.2 (24 %) and others (14.7 %), and is currently being used to replace wood fuel and run a generator that produces electricity for lighting and cooking purposes. The final treated effluent meets the acceptable minimum national environmental quality standards. The prototype is now not only turning the industrial wastes into value added products (energy and clean water) but is also serving as a model prototype for public-private partnership in developing scalable innovations for the sustainable management of all other agro-processing wastewaters in the country.
Author(s): Tadesse Alemu [sup.1], Eshetu Lemma [sup.1], Andualem Mekonnen [sup.1], Seyoum Leta [sup.1] Author Affiliations: (1) grid.7123.7, 0000000112505688, Center for Environmental Sciences, Addis Ababa University, , Addis ababa, Ethiopia Introduction [...]