Upflow Anaerobic Sludge Blanket Reactor Research Articles

Biological treatment of Hydrothermal Liquefaction (HTL) wastewater: Analytical evaluation of continuous process streams

In order to deal with hydrothermal liquefaction wastewater (HTWW), a new anaerobic-aerobic continuous process was developed. The process, which included a sequence of Up-Flow Anaerobic Sludge Blanket (UASB) and downstream aerobic Continuously Stirred Tank Reactor (CSTR), was tested on the HTWW obtained from Waste to Fuel® demo plant developed by ENI s.p.a. [1]. Performance of the system was evaluated in term of methane yield and chemical oxygen demand (COD) abatement capability. Detailed fate of organic compounds was evaluated through different analytical techniques, highlighting main issues and potential of HTWW biological treatment. The system was fed with neat HTWW (189 gCOD L−1) for 2.5 y, with variable organic loading rate (OLR) and minimal external inputs. UASB reactors converted most of HTWW organics into volatile fatty acids (VFA) and methane with concurrent precipitation of oily like insoluble, whereas aerobic CSTR removed VFA from anaerobic effluent. Under regime conditions (ORL equal to 0.5 gCOD L−1 d−1) COD decreased from 189 to 6.6 gCOD L-1, showing 97 % COD abatement with the coupled anaerobic-aerobic treatment. Such a COD abatement was obtained by means of multiple effects, namely biomethanation, precipitation of organic matter and aerobic oxidation of fermentation products (VFA produced in anaerobic digestion) and subsequent aerobic oxidation (in downstream aerobic reactor). These effects accounted for 43, 40 and 17 % of the total COD decrease, respectively. Inhibition phenomena were the key challenge for improving methane yields and system productivities. The overall results confirmed that valorization of HTWW is a feasible task, albeit rather challenging.

Methane recovery from acidic tofu wastewater using an anaerobic fixed-bed reactor with bamboo as the biofilm carrier

Wastewater generated during acid coagulation in tofu processing has high organic concentrations and low pH. Several small industries in Indonesia discharge such wastewater without treatment, necessitating economical treatment to control water pollution. In this study, the feasibility of methane production from the treatment of acidic tofu processing wastewater was investigated. For this, anaerobic treatment of tofu processing wastewater using a fixed-bed reactor employing cut bamboo as the carrier was examined and compared to an upflow anaerobic sludge blanket reactor. Without neutralization, the fixed-bed reactor outperformed the upflow anaerobic sludge blanket reactor at a chemical oxygen demand load of 4.3 kg chemical oxygen demand/m3 day. The highest total organic carbon removal efficiency and methane gas yield were 95% and 0.98 L/g total organic carbon removed, respectively. The two most abundant bacteria were the genus Paludibacter and the unclassified Bacteriodetes; both from the family Porphyromonadaceae. Hydrogenotrophic methanogens from the genera Methanoculleus and Methanobacterium were the dominant archaea, indicating that hydrogenotrophic methanogenesis was a major methane formation pathway.

Magnetic properties of biogenic selenium nanomaterials.

Bioreduction of selenium oxyanions to elemental selenium is ubiquitous; elucidating the properties of this biogenic elemental selenium (BioSe) is thus important to understand its environmental fate. In this study, the magnetic properties of biogenic elemental selenium nanospheres (BioSe-Nanospheres) and nanorods (BioSe-Nanorods) obtained via the reduction of selenium(IV) using anaerobic granular sludge taken from an upflow anaerobic sludge blanket (UASB) reactor treating paper and pulp wastewater were investigated. The study indicated that the BioSe nanomaterials have a strong paramagnetic contribution with some ferromagnetic component due to the incorporation of Fe(III) (high-spin and low-spin species) as indicated by electron paramagnetic resonance (EPR). The paramagnetism did not saturate up to 50,000 Oe at 5 K, and the hysteresis curve showed the coercivity of 100 Oe and magnetic moment saturation around 10 emu. X-ray photoelectron spectroscopy (XPS) and EPR evidenced the presence of Fe(III) in the nanomaterial. Signals for Fe(II) were observed neither in EPR nor in XPS ruling out its presence in the BioSe nanoparticles. Fe(III) being abundantly present in the sludge likely got entrapped in the extracellular polymeric substances (EPS) coating the biogenic nanomaterials. The presence of Fe(III) in BioSe nanomaterial increases the mobility of Fe(III) and may have an effect on phytoplankton growth in the environment. Furthermore, as supported by the literature, there is a potential to exploit the magnetic properties of BioSe nanomaterials in drug delivery systems as well as in space refrigeration.

Effect of low temperature on the performance of UASB reactor for municipal wastewater treatment: recent advances and future perspectives

Upflow anaerobic sludge blanket (UASB) reactor is a widely used anaerobic treatment technology, which is essential in municipal sewage treatment, in tropical and subtropical areas. However, UASB reactors have been underutilized in low-temperate zones due to the poor performance of UASB reactors under psychrophilic conditions. This study has three primary purposes: to review the performance of UASB reactors with different parameters, to describe the limiting factors at low temperatures, and to prospect the future solutions. In the low-temperature environment, lower COD removal efficiency and production of methane in the UASB reactor have been observed in various studies. The key limiting factors are increased dissolved methane, decreased activity of methanogens and hydrolytic bacteria. This article proposed that five technologies could reduce the impact of low temperature on the treatment of municipal wastewater by the UASB reactor, which are denitrifying anaerobic methane oxidation (DAMO), direct interspecies electron transfer (DIET), bio-electrochemical systems (BES), pre-hydrolysis, and degassing membrane (DM). These technologies are promising to be developed into highly-efficient engineering strategies for treating municipal wastewater in the UASB reactor at low temperatures in the future.

Up-Flow Anaerobic Sludge Blanket Reactors in Dye Removal: Mechanisms, Influence Factors, and Performance

Society faces eco-environmental challenges when it comes to managing industrial wastewaters. In particular, textile effluents are one of the main threats to living being due to toxic dyes. Technologies used to remove dye compounds include physicochemical and membrane filtration processes. However, since current technologies have several limitations, including high investment and energy demand, researchers have investigated cheaper and eco-friendly alternatives. Among them, anaerobic processes have been an effective method to decolourise dye-containing effluents. In that direction, the up-flow anaerobic sludge blanket (UASB) technology stands out in terms of high cost-effectiveness. The authors reviewed the published literature on UASB reactors in dye compounds removal. Mechanisms, merits, demerits, and technical aspects of UASB reactors are introduced. Challenges and opportunities are discussed. The major points are 1) mechanisms of dye removal in UASB reactors comprise mainly dye adsorption onto sludge granules and azo bond cleavage (biodegradation), 2) dye structure and concentration, external organic carbon source, redox mediators, and bioreactor operating conditions play a key role in the treatment performance, 3) UASB technology exhibits high decolourisation rates. Removal efficiencies of chemical oxygen demand and colour lie within the range of 60–85% and 75–96%, respectively. However, anaerobic treatments may not be able to mineralise by-products of anaerobic metabolisms. Consequently, post-treatment of the anaerobically treated effluent is required, and 4) the energy production during the decolourisation process in UASB reactors is estimated at 22 kWh per m3 of treated wastewater. Bio-energy recovery can promote wastewater valorisation and decrease the economic burdens of dye-containing effluents treatment. Future studies should focus on optimising influence parameters of full-scale UASB reactors and biogas recovery from dye-containing wastewater treatment.

Ecogenomics Reveals Microbial Metabolic Networks in a Psychrophilic Methanogenic Bioreactor Treating Soy Sauce Production Wastewater.

An ecogenomic analysis of the methanogenic microbial community in a laboratory-scale up-flow anaerobic sludge blanket (UASB) reactor treating soy sauce-processing wastewater revealed a synergistic metabolic network. Granular sludge samples were collected from the UASB reactor operated under psychrophilic (20°C) conditions with a COD removal rate >75%. A 16S rRNA gene amplicon sequencing-based microbial community analysis classified the major microbial taxa as Methanothrix, Methanobacterium, Pelotomaculaceae, Syntrophomonadaceae, Solidesulfovibrio, and members of the phyla Synergistota and Bacteroidota. Draft genomes of dominant microbial populations were recovered by metagenomic shotgun sequencing. Metagenomic- and metatranscriptomic-assisted metabolic reconstructions indicated that Synergistota- and Bacteroidota-related organisms play major roles in the degradation of amino acids. A metagenomic bin of the uncultured Bacteroidales 4484-276 clade encodes genes for proteins that may function in the catabolism of phenylalanine and tyrosine under microaerobic conditions. Syntrophomonadaceae and Pelotomaculaceae oxidize fatty acid byproducts presumably derived from the degradation of amino acids in syntrophic association with aceticlastic and hydrogenotrophic methanogen populations. Solidesulfovibrio organisms are responsible for the reduction of sulfite and may support the activity of hydrogenotrophic methanogens and other microbial populations by providing hydrogen and ammonia using nitrogen fixation-related proteins. Overall, functionally diverse anaerobic organisms unite to form a metabolic network that performs the complete degradation of amino acids in the psychrophilic methanogenic microbiota.

Sewage treatment at 4 °C in anaerobic upflow reactors with and without a membrane – performance, function and microbial diversity

In this study, we investigated the feasibility of anaerobic sewage treatment at extremely low temperatures (4 °C) using two reactor setups: Upflow anaerobic sludge blanket reactors (UASB) without and with (AnMBRUASB(UF)) a membrane.

Performance of anammox biofilm reactor under tropical temperature

Application of anaerobic ammonium oxidation (anammox) process for mainstream wastewater in the lower temperature is a current challenge where most of the anammox reactors planted in the sub-tropical country. The purpose of this study was to analyze the performance of nitrogen removal using anammox process at room temperature in a tropical country. The experiment was carried out using 300 mL an up-flow anaerobic sludge blanket (UASB) reactor in treating low ammonia concentration artificial wastewater at tropical temperature without any adjustment. The reactor filled with 50% in volume spiral-sheet plastic (polyethylene terephthalate) as the carrier. Anammox bacteria Candidatus Brocadia sinica as seeding acclimatized in room temperature for three months before the experiment. The reactor fed with 70 mg-N/L for both ammonium and nitrite with variations in hydraulic retention time (HRT) 24 hours and 12 hours. The maximum nitrogen removal rate (NRR) achieved 0.12 kg-N/(m3·d) at nitrogen loading rate (NLR) 0.14 kg-N/(m3·d) and NRR 0.25 kg-N/(m3·d) at NLR 0.28 kg-N/(m3·d). The anammox process was stable at room temperatures (15-28°C) in a tropical country for nitrogen removal and anammox bacteria grown on plastic media.

Effects of granular activated carbon and Fe-modified granular activated carbon on anammox process start-up.

In this study, granular activated carbon (GAC) and Fe-modified granular activated carbon (FeGAC) prepared by ultrasonic impregnation method were added into respective up-flow anaerobic sludge blanket (UASB) reactors to explore their effects on the anammox process start-up. The results showed that the time of anammox system start-up could be reduced from 108 d in R1 (control group) to 94 d in R2 (GAC reactor) and to 83 d in R3 (FeGAC reactor). After 120 days of operation, the nitrogen removal rates (NRR) of all reactors could reach more than 0.8 kg-N m−3 d−1. Extracellular polymeric substance (EPS) amount, heme c content and the anammox bacterial functional gene copy numbers gradually increased in all reactors with the passage of culture time, and manifested the superiority in R3 especially. High throughput sequencing revealed that Candidatus Kuenenia was the dominant species in all reactors in the end. It was also demonstrated that FeGAC markedly strengthened the growth and aggregation of anammox bacteria, which is promising for the practical application of the anammox process.

Mathematical approach towards non-stepwise performance assessment in HUASB reactor for wastewater treatment from pulp and paper mills

A lab-scale Hybrid Upflow Anaerobic Sludge Blanket (HUASB) reactor with a working volume of 6.5 litres has been taken for the performance analysis, in the treatability study of pulp and paper mill wastewater. In order to analyze the performance of the reactor, operational parameter like hydraulic retention time (HRT) was varied from 10, 20, 30 and 40 h. In addition to that, performance parameters like chemical oxygen demand (COD), pH, volatile fatty acids (VFA), alkalinity, gas production and VFA/alkalinity ratio are analyzed to check the reactor efficacy. The maximum COD removal efficiency of 81.3% is obtained at 40 h HRT, with gas production (methane content of 58%). Also, the obtained results are fitted to the kinetic models like the standard first order, first order and second order to evaluate the performance of the HUASB reactor.

A REVIEW ON ORGANIC REMOVAL OF MUNICIPAL AND INDUSTRIAL WASTEWATER USING UP-FLOW ANAEROBIC SLUDGE BLANKET (UASB) AND ITS APPLICATION IN ANAMMOX PROCESS

Anaerobic treatment processes are widely recognized as a sustainable wastewater management system for their encouraging results in treating highly concentrated wastewater (bCOD > 4000 mg/L) with low energy requirement, which is more economical than aerobic processes. High rate anaerobic reactors, particularly up-flow anaerobic sludge blanket (UASB) reactors, have been extensively employed worldwide due to their high volumetric organic capacity and less sludge yield. However, some limiting factors need to be resolved for large-scale applications. This review aims to emphasize the organic removal of municipal and industrial wastewater using UASB technology and its application in the anammox process in treating ammonia-rich wastewater.Keywords: Anaerobic, anammox, granulation, Up-flow Anaerobic Sludge Blanket (UASB)

On-Site Blackwater Treatment Fosters Microbial Groups and Functions to Efficiently and Robustly Recover Carbon and Nutrients.

Wastewater is considered a renewable resource water and energy. An advantage of decentralized sanitation systems is the separation of the blackwater (BW) stream, contaminated with human pathogens, from the remaining household water. However, the composition and functions of the microbial community in BW are not known. In this study, we used shotgun metagenomics to assess the dynamics of microbial community structure and function throughout a new BW anaerobic digestion system installed at The Netherlands Institute of Ecology. Samples from the influent (BW), primary effluent (anaerobic digested BW), sludge and final effluent of the pilot upflow anaerobic sludge blanket (UASB) reactor and microalgae pilot tubular photobioreactor (PBR) were analyzed. Our results showed a decrease in microbial richness and diversity followed by a decrease in functional complexity and co-occurrence along the different modules of the bioreactor. The microbial diversity and function decrease were reflected both changes in substrate composition and wash conditions. Our wastewater treatment system also decreased microbial functions related to pathogenesis. In summary, the new sanitation system studied here fosters microbial groups and functions that allow the system to efficiently and robustly recover carbon and nutrients while reducing pathogenic groups, ultimately generating a final effluent safe for discharge and reuse.

Blending of microbial inocula: An effective strategy for performance enhancement of clayware Biophotovoltaics microbial fuel cells

Performance of clayware Biophotovoltaics (BPVs) with three variants of inocula namely anoxygenic photosynthetic bacteria (APB) rich Effective microbes (EM), Up-flow anaerobic sludge blanket reactor (UASB) sludge, SUPER-MIX the blend of EM and UASB inoculum were evaluated on the basis of electrical output and pollutant removal. SUPER-MIX inocula with microbial community comprising of 28.42% APB and 71.58% of other microbes resulted in peak power density of 275 mW/m2, 69.3 ± 1.74% Coulombic efficiency and 91 ± 3.96% organic matter removal. The higher performance of the SUPER-MIX than EM and UASB inocula was due to the syntrophic associations of the various APBs and other heterogenous microorganisms in perfect blend which improved biocatalytic electron transfer, electro-kinetic activities with higher redox current and bio-capacitance. The promising performance of clayware BPVs with SUPER-MIX inocula indicate the possibility of BPVs to move towards the scale-up process to minimize the investment towards pure culture by effective blending strategies of inocula.

Impact of UASB reactors operation mode on the removal of estrone and 17α-ethinylestradiol from wastewaters

This work aims to compare the performance of the continuous operation (CO) and intermittent operation (IO) of upflow anaerobic sludge blanket (UASB) reactors for the removal of estrone (E1) and 17α-ethinylestradiol (EE2) from wastewaters. Results suggest that the IO contribute to the improvement of the overall removal of estrogens (above 95% for E1 and EE2) when compared to CO (49% for E1 and 39% for EE2). For both CO and IO, biodegradation was the main removal mechanism for E1, while for EE2, adsorption to sludge was the major removal pathway. Moreover, a higher biodegradation of estrogens was obtained with the IO compared to CO (69.4% vs. 43.3% for E1 and 21.8% vs. 8.0% for EE2). The favourable effect of IO can be justified by effluent recirculation during the feedless period which promotes the adaptation of microbial biomass to estrogens' biodegradation.

Anaerobic biological treatment of EG/PG water-soluble copolymer coupled with down-flow hanging sponge reactor

Water-soluble copolymers such as polyvinylpyrrolidone and polyvinyl alcohol have been widely used as detergents, paints, and chemical intermediates in many industrial processes, leading to environmental concerns associated with high-volume organic compound wastewater. Therefore, in this study, a combined upflow anaerobic sludge blanket (UASB) reactor and downflow hanging sponge (DHS) biosystem has been applied for the treatment of synthetic water-soluble copolymer wastewater. Copolymer consisted of ethylene glycol and propylene glycol with a total molecular weight of 8,500, commonly preferred in the automobile parts processing factory, were included in influent. Overall, the whole UASB–DHS system achieved a favorable chemical oxygen demand (COD) removal efficiency of 86% ± 7%. In more detail, with an organic loading rate of 2.12 kg-COD ⋅ m −3 ⋅ day −1 , the UASB reactor enhanced the biodegradability of wastewater, and reached COD removal efficiency of 61% ± 16%. Meanwhile, gel permeation chromatography analysis indicated that the molecular weight of the wastewater was primarily reduced in the DHS reactor. In addition, massive 16S rRNA gene sequencing showed that polyethylene-glycol-degrading bacteria Pelobacter sp. was predominant in the UASB granular sludge. • First report on integrated biological treatment of water-soluble copolymers. • UASB reactor after adaptation can recover energy in the form of methane. • Total system achieved chemical oxygen demand removal efficiency of 86% ±7%. • Molecular weight reduction in the process was mainly occurred in the DHS. • UASB-DHS system was applicable to this wastewater.

Jet-nozzle based improvement of dissolved H2 concentration for efficient in-situ biogas upgrading in an up-flow anaerobic sludge blanket (UASB) reactor

Improvement of dissolved concentration and mass transfer coefficient (KLa) of H2 is a main strategy for efficient biogas upgrading process. In this study, Jet nozzle reactor (JNR) was applied to improve dissolved H2 (DH2) concentration and KLa for successful in-situ biogas upgrading in an up-flow anaerobic sludge blanket (UASB) reactor. JNR could improve the DH2 concentration and KLa to 1.71 and 1.72 times higher than those of control reactor, respectively. Increased DH2 concentration and KLa contributed to increase CH4 content to 96.1% in UASB combined with JNR (JN-UASB). JN-UASB achieved maximum H2 conversion efficiency of 97.9% and minimum H2 content of 3.9% in biogas. Community of hydrogenotrophic methanogens and efficiency of H2 conversion in JN-UASB were 1.1 and 1.3 times higher than those in control UASB (C-UASB), respectively. This study confirmed that DH2 concentration and KLa increased by JNR affected the improvement of H2 methanation efficiency via rapid hydrogenotrophic methanogenesis. The findings of this study provide technical strategy and further research direction to upgrade biogas.

Water-energy-food security nexus based selection of energy recovery from wastewater treatment technologies: An extended decision making framework under intuitionistic fuzzy environment

According to the increasing demand of human society to the electrical energy, the choice of a comprehensive decision making for energy recovery from wastewater treatment technologies selection is very important. Water-energy-food (WEF) security nexus which is one of the most notable concepts in recent years that have emerged in research across many disciplines, can be used as a decision making tool to evaluate actions in different energy sectors. Behbahan city in the southwest of Iran has been chosen for the experiment. An extended methodology based on two multi-criteria decision making (MCDM) methods called entropy and linear assignment under intuitionistic fuzzy environment has been chosen to support the synthetic decision to prioritize energy recovery from wastewater treatment technologies. Thirteen criteria including water security principles (Access, Safety, and Affordability), energy security principles (Availability, Accessibility, Affordability, Acceptability, Applicability, and Adaptability) and food security principles (Availability, Access, Utilization, and Stability) have been considered. In terms of the warm and dry weather in Behbahan city, choosing the up-flow anaerobic sludge blanket reactor (UASB) option as the most appropriate option seems rational. The anaerobic baffled reactor (ABR), micro-algae cultivation (MAC), and microbial fuel cells (MFC) options were selected as the second, third, and fourth options, respectively.

Reduction and partitioning of viral and bacterial indicators in a UASB reactor followed by high rate algal ponds treating domestic sewage

Human enteric pathogens are a major global concern, as they are responsible for thousands of preventable deaths every year. New pathogens in wastewater are constantly emerging. For example, SARS-CoV-2 has been recently detected in domestic sewage and primary sludge. Knowledge about the reduction of viruses in wastewater treatment and their partitioning between the treated liquid effluent versus the sludge or biosolids is still very scarce, especially in countries with emerging economies and tropical climates. Upflow anaerobic sludge blanket (UASB) reactors are among the top three most commonly used technologies for the treatment of sewage in Latin America and the Caribbean, and their use has become increasingly common in many other low- and middle-income countries. High-rate algal ponds (HRAP) are regarded as a sustainable technology for the post-treatment of UASB effluent. This study evaluated the overall reduction and the liquid-solid partitioning of somatic coliphages, F-specific coliphages, and E. coli in a pilot-scale system comprised of a UASB reactor followed by HRAPs treating real wastewater. Average log removal for somatic and F-specific coliphages were 0.40 and 0.56 for the UASB reactor, and 1.15 and 1.70 for HRAPs, respectively. The overall removal of both phages in the system was 2.06-log. Removal of E. coli was consistently higher. The number of viruses leaving the system in the UASB solids and algal biomass was less than 10% of the number leaving in the clarified liquid effluent. The number of E. coli leaving the system in solids residuals was estimated to be approximately one order of magnitude higher than the number of E. coli leaving in the liquid effluent. Results from this study demonstrate the suitability of UASB-HRAP systems to reduce viral and bacterial indicators from domestic sewage and the importance of adequately treating sludge for pathogen reduction before they are used as biosolids.

Role of syntrophic acetate oxidation and hydrogenotrophic methanogenesis in co-digestion of blackwater with food waste

Blackwater collected from toilets represents a type of sustainable bioenergy resource in the modern sanitation system, while its biomethane recovery efficiencies through anaerobic digestion were limited by slow hydrolysis and inhibited methanogenesis due to a large fraction of solid organics and high free ammonia concentrations. In the current study, food waste and blackwater co-digestion was performed in an up-flow anaerobic sludge blanket (UASB) reactor (35 °C). Co-substrates with increasing food waste proportions were stepwise applied to demonstrate the threshold organic loading rate (OLR). Co-digestion effectively enhanced substrate hydrolysis efficiency by up to 86.1% and methanisation rate by up to 39.7% compared to blackwater mono-digestion. Hydrogenotrophic methanogens showed predominance in both feeding conditions. The dominant bacterial groups shifted from genus Bacteroides to T78, and methanogenic groups shifted from genus Methanogenium to Methanoculleus and Methanospirillum when the operation system shifted from blackwater mono-digestion to food waste co-digestion. The microbial community structures and the isotopic carbon analysis for CH4 and CO2 in the produced biogas indicated that a combined syntrophic acetate oxidation (SAO) and hydrogenotrophic methanogenesis (HM) pathway was established throughout the operation. The enhanced substrates’ properties including higher carbon/nitrogen (C/N) ratios and more readily biodegradable organics in food waste and blackwater co-digestion system contributed to the enhancements in biomethane recovery and microbial development compared to blackwater mono-digestion. The OLR stress under the overloaded condition negatively affected the microbial community structure and resulted in process deterioration.

Leachate after aerobic stabilization of municipal solid waste supplemented by waste glycerine from saponification to improve biogas production during co-digestion

Co-digestion of leachate from aerobic stabilization of OFMSW (leachateOFMSW) with waste glycerine (WG) from saponification is a promising approach for municipal waste and wastewater treatment. The effect of feedstock composition on co-digestion efficiency was examined. Two feedstocks with different contents of WG (6%, 13%) were used, which affected the COD:TKN ratios in those feedstocks (60, 100). LeachateOFMSW provided nitrogen and the micro- and macroelements. In both feedstocks, the N–NH4:TKN ratio was low (0.08), indicating that the dominant form of nitrogen was organic nitrogen (Norg). Co-digestion was carried out in upflow anaerobic-sludge blanket reactors (37 ± 2 °C; OLR, 4 kg COD m−3 d−1).This process ensured highly effective COD removal (over 97%). At a feedstock COD:TKN ratio of 60, specific biogas production (SBP) was ca. 0.22 m3 kg−1 COD, and methane content, 61.6%. Increasing the COD:TKN ratio to 100 significantly increased SBP to ca. 0.36 m3 kg−1 COD, but reduced biogas quality (54.2% CH4). Although Norg had to be ammonified to ammonium because of the low N–NH4:TKN ratio in the feedstocks, the ammonium concentration in the post-processing wastewater remained low. Moreover, the low ammonium concentrations meant that the pH (8.8) did not have a toxic effect on anaerobic co-digestion (free ammonia concentrations were merely ca. 28 and 5.5 mg L−1, respectively). However, at higher feedstock COD:TKN ratios than those tested, ammonium could be exhausted, which would impede methane production. These results indicate that WG is an effective co-substrate for leachateOFMSW if an appropriate amount of WG is added to the feedstock.