Biological treatment of leachate from stabilization of biodegradable municipal solid waste in a sequencing batch biofilm reactor

Abstract

The aim of this study was to determine the effectiveness of pollutant removal in sequencing batch biofilm reactors (with floating or submerged carriers) when treating nitrogen- and organic-rich real leachate generated during aerobic stabilization of the biodegradable municipal solid waste. A control reactor contained suspended activated sludge. The share of leachate in synthetic wastewater was 10%, which resulted in ratios of chemical oxygen demand and biochemical oxygen demand to total Kjeldahl nitrogen in the influent of ca. 11 and ca. 8.5, respectively. Regardless of whether the reactors contained carriers or not, the effectiveness of nitrification (84.2–84.3%) and of the removal of chemical oxygen demand (86.5–87.0%), biochemical oxygen demand (95.5–98.0%) and ammonium (88.9–89.3%) did not differ. However, the presence of carriers and their type determined in which phase of the cycle denitrification occurred. In the control reactor, denitrification took place during mixing phase with the effectiveness of ca. 43.2% (57.7% of the total nitrogen removal). During aeration, the oxygen content increased rapidly, thus reduced the possibility of simultaneous denitrification. In reactors with carriers, in the aeration phase, not only nitrification but also denitrification occurred. The increase in oxygen content in wastewater was slower, which could have caused dissolved oxygen gradients and anoxic zones in deeper layers of the biofilm and flocks. In the reactor with floating carriers, the effectiveness of denitrification and total nitrogen removal increased 1.23- and 1.10-times, respectively, as compared to the control reactor. The highest efficiencies (67.7% and 73.0%, respectively) were observed in the reactor with submerged carriers.

Post-Treatment of the Effluent from Anaerobic Digestion of the Leachate in Two-Stage SBR System Using Alternative Carbon Sources

“…The low ratio of N-NH 4 /TKN in the effluent after AD may have resulted from the fact that TKN in the leachate from aerobic stabilization of OFMSW consisted of ca. 30% ammonium, which was stated also in a previous study [10]. Koc-Jurczyk and Jurczyk [11] treated old landfill leachate (4125 mg COD/L, 636 mg BOD 5 /L (BOD 5 /COD ratio of 0.15), 775 mg N-NH 4 /L and 850 mg TKN/L) in three SBRs, one contained suspended activated sludge, whereas two SBRs additionally contained foam carriers.…”

Effect of Alkali-NaOH Pretreatment on Methane Production from Anaerobic Digestion of Date Palm Waste

“…The volume of methane is measured when the water moves from the cylindrical gasmeter, made of Pyrex, to a graduated tube by the water displacement method (7). The methane volume produced was daily measured using the graduated tube under the ambient condition of the room (8).…”

“…Nevertheless, the production of biogas or methane can be improved by increasing the solubility of organic matter during the anaerobic digestion process (Wong et al, 2018). Different pretreatments were used in order to improve biodegradability and methane production, such as physical, chemical and biological (Bernat et al, 2020). The use of the pretreatment stage is to improve the physical accessibility of lignocellulosic matter to microbes (Karouach et al, 2020) and modify the structure of cellulosic materials, which are complex, with decreasing degree of polymerization, weakening of the lignin and carbohydrates bonds and increased surface area of particles (Mudhoo, 2012).…”

Enhanced landfill leachate treatment in sequencing batch biofilm reactors (SBBRs) amended with zeolite and biochar

“…[10][11][12] Goh et al 11 used a SBBR with sponge cube media to treat synthetic wastewater with an initial TAN concentration of 48 mg L −1 ; this configuration increased TAN removal from 86% to ∼100% compared with an SBR. Bernat et al 13 found that adding polyethylene ring-shaped carriers to SBRs increased denitrification effectiveness and TN removal from aerobically stabilized leachate 1.23-and 1.10-fold, respectively.…”