Evaluation of effluents from bench-scale treatment combinations for landfill leachate in Ibadan, Nigeria

Abstract

The removal of pollutants in landfill leachate was investigated using constructed wetlands, a trickling filter, alum flocculation and coagulation, and a sequencing batch reactor in various combinations. Thirteen combined operations were investigated involving three out of the four unit treatment methods in series. The study was conducted because unit operations, though achieved reductions in pollutants concentrations had effluent values above the national regulatory guideline values. The suspended solids of effluents were permissible in most treatment processes, while reductions in 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and ammonia (NH3) of leachates ranged from 80% to 97%; 86% to 97% and 92% to 98% respectively. However, there were significant increases in nitrate (85%) and dissolved oxygen of treatment (218%). In addition, the characteristics of the recommended treatment sequence, involving constructed wetlands, alum and trickling filter produced effluents with reductions in colour (97%), alkalinity (97%), BOD (97%), COD (97%) and NH3 (98%), and in metals, except nickel (29% reduction from the influent values). The recommended treatment combination is suitable for effective leachate management at the landfill. The cost of constructing and operating the recommended treatment combination at the facility, for 5 years, would be NGN6,009,750.00 ($38,036.39). The performance should be monitored on site prior to full adoption if effluent characteristics remain consistently low over dry and wet seasons.

Removal of ammoniacal nitrogen from municipal landfill leachate with floating <i>Typha domingensis</i> (Typhaceae)

“…Nitrogen is a constituent of proteins, chlorophyll and many biological components, and in organic matter from landfill leachate, it is broken down into amino acids and then reduced to ammoniacal nitrogen. In the presence of DO, ammoniacal nitrogen is oxidized to nitrite and then to nitrate, which explains the increase of nitrate in the effluents (Aluko and Sridhar, 2014). The process of oxidation of ammonia to nitrite and then to nitrate is called nitrification and occurs by the action of nitrifying bacteria that grow in aerobic medium (Barbieri et al, 2014).…”

Preliminary assessment of soil contamination by trace metals in peri-urban municipal landfills in Ibadan, Nigeria

“…A detailed description of the study area as well as the geographical location of the sampling sites is available elsewhere 25,[30][31][32] . Soil sampling, pre-treatment and preservation was carried out according to 33 .…”

Enhanced in-Situ Reduction of Leachate Parameters Due to Aeration and Leachate Recirculation in Pilot Scale MSW Bioreactor Landfill Models in Tropical Climate

“…Leachate is a mixture of aqueous effluent generated by excess rainwater percolating through the municipal solid waste in landfill which contains a high concentration of organic and inorganic contaminants including humid acids, ammonia nitrogen, heavy metals, xenobiotics, chlorinated organic and inorganic salts. (Abbas et al, 2009;Aluko et al, 2003;Manandhar et al, 2012;Taneja 2011;and Wiszniowski et al, 2006). However, the content of heavy metal in leachate is comparatively low as a result of the attenuation process taking place in the disposed waste (Manandhar et al, 2012 andRenou et al, 2008).…”