Pollutant removal from landfill leachate via two-stage anoxic/oxic combined membrane bioreactor: Insight in organic characteristics and predictive function analysis of nitrogen-removal bacteria

Two-stage membrane bioreactor (MBR) system was applied to the treatment of landfill leachate from a solid waste disposal site in Thailand. The first stage anoxic reactor was equipped with an inclined tube module for sludge separation. It was followed by an aerobic stage with a hollow fiber membrane module for solid liquid separation. Mixed liquor sludge from the aerobic reactor was re-circulated back to anoxic reactor in order to maintain constant mixed liquor suspended solids (MLSS) concentration in the aerobic reactor. The removal of micro-pollutants from landfill leachate along the treatment period of 300 days was monitored. The results indicated that two-stage MBRs could remove biochemical oxygen demand (BOD), chemical oxygen demand (COD) and NH4+ by 97, 87 and 91% at steady operating condition. Meanwhile organic micro-pollutant removals were 50–76%. The removal efficiencies varied according to the hydrophobic characteristic of compounds but they were improved during long-term MBR operation without sludge discharge.

Download Full-text

Characterization of Dissolved Organic Matter in Landfill Leachate during Two–Stage Membrane Bioreactor Treatment

Journal of Applied Membrane Science & Technology ◽

10.11113/amst.v15i1.98 ◽

2017 ◽

Vol 15 (1) ◽

Author(s):

S. Sanguanpak ◽

C. Chiemchaisri ◽

W. Chiemchaisri ◽

K. Yamamoto

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Landfill Leachate ◽

Membrane Bioreactor ◽

Disposal Site ◽

Solid Waste Disposal ◽

High Concentration ◽

Absorption Bands ◽

Two Stage

Landfill leachate is a complex wastewater containing high concentration of dissolved organic matter (DOM). In this study, DOM in raw leachate and treated water from pilot–scale two–stage membrane bioreactor (MBR) installed at solid waste disposal site were investigated by using fractionation method, fluorescence excitation–emission matrix spectroscopy (FEEM) and fourier transform infrared (FTIR). The fractionation results showed hydrophilic (Hyl) compound was the most abundant fraction in DOM of raw leachate, whereas the dominant fraction of DOM in mixed liquor inside MBR and its effluent was fulvic acid (FA). The fluorescent peaks of protein-like, humic and fulvic–like substances were detected in influent DOM, while the fluorescence peaks of MBR and effluent DOM were humic and fulvic-like substances. From the FTIR results, absorption bands that could be related to humic acid (HA) and FA were found in both MBR and effluent DOM. The characterization of DOM indicated that the most of Hyl and protein–like substances could be significantly removed by microbial process in MBR. Furthermore, a part of humic substance (HA and FA) could be eliminated by microbial and filtration processes.

Download Full-text

Autotrophic ammonia removal from landfill leachate using anaerobic membrane bioreactor

Linnaeus Eco-Tech ◽

10.15626/eco-tech.2014.016 ◽

2017 ◽

Author(s):

S. Suneethi ◽

Kurian Joseph

Keyword(s):

Nitrogen Removal ◽

Landfill Leachate ◽

Membrane Bioreactor ◽

Loading Rate ◽

Ammonia Removal ◽

Nitrogen Loading ◽

Ammonium Oxidation ◽

Anaerobic Membrane Bioreactor ◽

N Removal ◽

Anammox Process

Anaerobic Membrane Bioreactor (AnMBR) is an innovative high cell density system having complete biomass retention, high reactor loading and low sludge production and suitable for developing slow growing autotrophic bacterial cultures such as ANAMMOX. The Anaerobic Ammonium Oxidation (ANAMMOX) process is an advanced biological nitrogen removal removes ammonia using nitrite as the electron acceptor without oxygen. The NH4+-N in the landfill leachate that is formed due to the release of nitrogen from municipal solid waste (MSW), when discharged untreated, into the surface water can result in eutrophication, aquatic toxicity and emissions of nitrous oxide (N2O) to atmosphere. Besides, NH4+-N accumulation in landfills poses long term pollution issue with significant interference during post closure thereby requiring its removal prior to ultimate disposal into inland surface waters. The main objective of this study was to investigate the feasibility and treatment efficiency of treating landfill leachate (to check) for removing NH4+-N by adopting ANAMMOX process in AnMBR. The AnMBR was optimized for Nitrogen Loading Rate (NLR) varying from 0.025 to 5 kg NH4+-N/ m3/ d with hydraulic retention time (HRT) ranging from 1 to 3 d. NH4+-N removal efficacy of 85.13 ± 9.67% with the mean nitrogen removal rate (NRR) of 5.54 ± 0.63 kg NH4+-N/ m3/ d was achieved with nitrogen loading rate (NLR) of 6.51 ± 0.20 kg NH4+- N/ m3/ d at 1.5 d HRT. The nitrogen transformation intermediates in the form of hydrazine (N2H4) and hydroxylamine (NH2OH) were 0.008 ± 0.005 mg/L and 0.006 ± 0.001 mg/L, respectively, indicating co-existence of aerobic ammonia oxidizers (AOB) and ANAMMOX. The free ammonia (NH3) and free nitrous acid (HNO2) concentrations were 26.61 ± 16.54 mg/L and (1.66 ± 0.95) x 10-5 mg/L, preventing NO2--N oxidation to NO3--N enabling sustained NH4+- N removal.

Download Full-text