Co-treatment of old landfill leachate and municipal wastewater in sequencing batch reactor (SBR): effect of landfill leachate concentration

Abstract

Sequencing batch reactor (SBR) was assessed for direct co-treatment of old landfill leachate and municipal wastewater for chemical oxygen demand (COD), nutrients and turbidity removal. Nitrogen removal was achieved by sequential nitrification and denitrification under post-anoxic conditions. Initially, SBR operating conditions were optimized by varying hydraulic retention time (HRT) at 20% (v/v) landfill leachate concentration, and results showed that 6 d HRT was suitable for co-treatment. SBR performance was assessed in terms of COD, ammonia, nitrate, phosphate, and turbidity removal efficiency. pH, mixed liquor suspended solids, mixed liquor volatile suspended solids (MLVSS), and sludge volume index were monitored to evaluate stability of SBR. MLVSS indicated that biomass was able to grow even at higher concentrations of old landfill leachate. Ammonia and nitrate removal efficiency was more than 93% and 83%, respectively, whereas COD reduction was in the range of 60–70%. Phosphate and turbidity removal efficiency was 80% and 83%, respectively. Microbial growth kinetic parameters indicated that there was no inhibition of biomass growth up to 20% landfill leachate. The results highlighted that SBR can be used as an initial step for direct co-treatment of landfill leachate and municipal wastewater.

Sequencing batch reactor technology for landfill leachate treatment: A state-of-the-art review

“…Anaerobic systems offer advantages such as: high organic loading rates capacity; methane production; low sludge generation and the capability of retaining microbes with special functions (Miao et al, 2016). Several studies proved the biological treatment processes based on suspended-growth biomass, exhibit satisfactory and consistent performance in terms of organic carbon and nutrients removal due to their simplicity and cost-effectiveness (Aziz et al, 2012;Contrera et al, 2014;Luo et al, 2020;Mojiri et al, 2014;Ranjan et al, 2016;Yin et al, 2018). Thus, providing enough hydraulic residence time.…”

“…Highly conductive leachate indicates a high concentration of dissolved solids which would provide adsorptive sites for biofilm inoculated for pollutants degradation. Low BOD/COD ratio and slightly high pH indicates that landfill leachate is in a stabilized state with minimal biodegradability of the organic components present (Ranjan et al, 2016). The COD/TOC ratio of the leachate < 2, is an indication of non-biodegradability .…”

Impact of the Biological Cotreatment of the Kalina Pond Leachate on Laboratory Sequencing Batch Reactor Operation and Activated Sludge Quality

“…Similarly, Ghanizadeh and Sarrafpour [67] found that an increase in pH from 5.7 to 9.0 resulted in a significant decrease in the SVI from 96 to 44 mL/g. A considerable drop in the SVI from 90 and 80 mL/g to 30 and 20 mL/g was also observed with an increase in the concentration of leachate from a municipal solid waste dumpsite in wastewater from 2.5 to 15% and 40% in India and Poland, respectively [16,68]. An SVI below 70 mL/g may result in the turbid effluent associated with the dispersed growth of microorganisms and the formation of small pin flocs [69].…”

Performances of sequential denitrification and partial nitrification process for treatment of landfill leachate

“…Spagnia and Marsili-Libelli [44] reported that low COD removal (about 20-30%) was obtained in SBR due to the low biodegradability in the LFL. Also, Ranjan [45] reported that COD removal was about 60-70%, but the NH4 + removal efficiency of more than 93% was obtained in SBR during LFL treatment.…”