Efficient and selective removal of Pb(Ⅱ) from landfill leachate using L-serine-modified polyethylene/polypropylene nonwoven fabric synthesized via radiation grafting technique

In this study,to efficiently remove Pb(Ⅱ) from aqueous environments,a novel L-serine-modified polyethylene/polypropylene nonwoven fabric sorbent(NWF-serine)was fabricated through the radiation grafting of glycidyl methacrylate and subsequent L-serine modification.The effect of the absorbed dose was investigated in the range of 5–50 kGy.NWF-serine was characterized by Fourier transform infrared spectroscopy,thermogravimetric analysis,and scanning electron microscopy.Batch adsorption tests were conducted to investigate the influences of pH,adsorption time,temperature,initial concentration,and sorbent dosage on the Pb(Ⅱ) adsorption performance of NWF-serine.The results indicated that Pb(Ⅱ) adsorption onto NWF-serine was an endothermic process,following the pseudo-second-order kinetic model and Langmuir isotherm model.The saturated adsorption capacity was 198.1 mg/g.NWF-serine exhibited Pb(Ⅱ) removal rates of 99.8% for aqueous solutions with initial concentrations of 100 mg/L and 82.1% for landfill leachate containing competitive metal ions such as Cd,Cu,Ni,Mn,and Zn.Furthermore,NWF-serine maintained 86% of its Pb(Ⅱ) uptake after five use cycles.The coordination of the carboxyl and amino groups with Pb(Ⅱ) was confirmed using X-ray photoelectron spectroscopy and extended X-ray absorption fine structure analysis.

Advanced landfill leachate treatment using a two-stage UASB-SBR system at low temperature

A two-stage upflow anaerobic sludge blanket （UASB） and sequencing batch reactor （SBR） system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen （TN） removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supematant was pumped into the first-stage UASB （UASB1） to achieve simultaneous denitrification and methanogenesis. The results showed that UASB1 played an important role in COD removal and UASB2 and SBR further enhanced the nutrient removal efficiency. When the organic loading rates of UASB1, UASB2 and SBR were 11.95, 1.63 and 1.29 kg COD/（m^3.day）, respectively, the total COD removal efficiency of the whole system reached 96.7%. The SBR acted as the real undertaker for NH4^＋-N removal due to aerobic nitrification. The system obtained about 99.7% of NH4^＋-N removal efficiency at relatively low temperature （14.9-10.9℃）. More than 98.3% TN was removed through complete denitrification in UASB 1 and SBR. In addition, temperature had a significant effect on the rates of nitrification and denitrification rather than the removal of TN and NH4^＋-N once the complete nitrification and denitrification were achieved.

An autotrophic nitrogen removal process:Short-cut nitrification combined with ANAMMOX for treating diluted effluent from an UASB reactor fed by landfill leachate

A combined process consisting of a short-cut nitrification （SN） reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed （ANAMMOX） reactor was developed to treat the diluted effluent from an upflow anaerobic sludge bed （UASB） reactor treating high ammonium municipal landfill leachate.The SN process was performed in an aerated upflow sludge bed （AUSB） reactor （working volume 3.05 L）,treating about 50% of the diluted raw wastewater.The ammonium removal efficiency and the ratio of NO 2 N to NOx-N in the effluent were both higher than 80%,at a maximum nitrogen loading rate of 1.47 kg/（m 3 ·day）.The ANAMMOX process was performed in an UASB reactor （working volume 8.5 L）,using the mix of SN reactor effluent and diluted raw wastewater at a ratio of 1：1.The ammonium and nitrite removal efficiency reached over 93% and 95%,respectively,after 70-day continuous operation,at a maximum total nitrogen loading rate of 0.91 kg/（m 3 ·day）,suggesting a successful operation of the combined process.The average nitrogen loading rate of the combined system was 0.56 kg/（m 3 ·day）,with an average total inorganic nitrogen removal efficiency 87%.The nitrogen in the effluent was mostly nitrate.The results provided important evidence for the possibility of applying SN-ANAMMOX after UASB reactor to treat municipal landfill leachate.

Nitrogen removal via nitrite from municipal landfill leachate

A system consisting of a two-stage up-flow anaerobic sludge blanket （UASB）, an anoxic/aerobic （A/O） reactor and a sequencing batch reactor （SBR）, was used to treat landfill leachate. During operation, denitrification and methanogenesis took place simultaneously in the first stage UASB, and the effluent chemical oxygen demand （COD） was further removed in the second stage UASB. Then the denitrification of nitrite and nitrate in the returned sludge by using the residual COD was accomplished in the A/O reactor, and ammonia was removed via nitrite in it. Last but not least, the residual ammonia was removed in SBR as well as nitrite and nitrate which were produced by nitrification. The results over 120 d （60 d for phase I and 60 d for phase II） were as follows： when the total nitrogen （TN） concentration of influent leachate was about 2500 mg/L and the ammonia nitrogen concentration was about 2000 mg/L, the shortcut nitrification with 85%-90% nitrite accumulation was achieved stably in the A/O reactor. The TN and ammonia nitrogen removal efficiencies of the system were 98% and 97%, respectively. The residual ammonia, nitrite and nitrate produced during nitrification in the A/O reactor could be washed out almost completely in SBR. The TN and ammonia nitrogen concentrations of final effluent were about 39 mg/L and 12 mg/L, respectively.

Control factors of partial nitritation for landfill leachate treatment

Anaerobic ammonium oxidation （ANAMMOX） technology has potential technical superiority and economical efficiency for the nitrogen removal from landfill leachate, which contains high-strength ammonium nitrogen （NH4^＋-N） and refractory organics. To complete the ANAMMOX process, a preceding partial nitritation step to produce the appropriate ratio of nitrite/ammonium is a key stage. The objective of this study was to determine the optimal conditions to acquire constant partial nitritation for landfill leachate treatment, and a bench scale fixed bed bio-film reactor was used in this study to investigate the effects of the running factors on the partial nitritation. The results showed that both the dissolved oxygen （DO） concentration and the ammonium volumetric loading rate （Nv） had effects on the partial nitritation. In the controlling conditions with a temperature of 30±1℃, Nv of 0.2-1.0 kg NH4＋-N/（m^3·d）, and DO concentration of 0.8-2.3 mg/L, the steady partial nitritation was achieved as follows： more than 94% partial nitritation efficiency （nitrite as the main product）, 60%-74% NH4^＋-N removal efficiency, and NO2^--N/NH4^＋-N ratio （concentration ratio） of 1.0-1.4 in the effluent.The impact of temperature was related to Nv at certain DO concentration, and the temperature range of 25-30℃ was suitable for treating high strength ammonium leachate. Ammonium-oxidizing bacteria （AOB） could be acclimated to higher FA （free ammonium） in the range of 122-224 mg/L. According to the denaturing gradient gel electrophoresis analysis result of the bio-film in the reactor, there were 25 kinds of 16S rRNA gene fragments, which indicated that abundant microbial communities existed in the bio-film, although high concentrations of ammonium and FA may inhibit the growth of the nitrite-oxidizing bacteria （NOB） and other microorganisms in the reactor.

Organic matter and concentrated nitrogen removal by shortcut nitrification and denitrification from mature municipal landfill leachate

An UASB＋Anoxic/Oxic （A/O） system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and high ammonia concentration. To make the best use of the biodegradable COD in the leaehate, the denitrifieation of NOx^--N in the reeireulation effluent from the elarifier was carried out in the UASB. The results showed that most biodegradable organic matters were removed by the denitrifieation in the UASB. The NH4^＋-N loading rate （ALR） of A/O reactor and operational temperature was 0.28- 0.60 kg NH4^＋-N/（m^3-d） and 17-29℃ during experimental period, respectively. The short-cut nitrification with nitrite accumulation efficiency of 90%-99% was stabilized during the whole experiment. The NH4^＋-N removal efficiency varied between 90% and 100%. When ALR was less than 0.45 kg NH4^＋-N/（m^3.d）, the NH4^＋-N removal efficiency was more than 98%. With the influent NH4^＋-N of 1200-1800 mg/L, the effluent NH4^＋-N was less than 15 mg/L. The shortcut nitrification and denitrifieation can save 40% carbon source, with a highly efficient denitrifieation taking place in the UASB. When the ratio of the feed COD to feed NH4^＋-N was only 2-3, the total inorganic nitrogen （TIN） removal efficiency attained 67%-80%. Besides, the sludge samples from A/O reactor were analyzed using FISH. The FISH analysis revealed that ammonia oxidation bacteria （AOB） accounted for 4% of the total eubaeterial population, whereas nitrite oxidation bacteria （NOB） accounted only for 0.2% of the total eubaeterial population.

Three-stage aged refuse biofilter for the treatment of landfill leachate

A field-scale aged refuse （AR） biofilter constructed in Shanghai Refuse Landfill, containing about 7000 m^3 aged refuse inside, was evaluated for its performance in the treatment of landfill leachate. This AR biofilter can be divided into three stages and can manage 50 m^3 landfill leachate per day. The physical, chemical, and biological characteristics of AR were analyzed for evaluating the AR biofilter as leachate treatment host. The results revealed that over 87.8%-96.2% of COD and 96.9%-99.4% of ammonia nitrogen were removed by the three-stage AR biofilter when the infiuent leachate COD and ammonia nitrogen concentration were in the range 5478-10842 mg/L and 811-1582 mg/L, respectively. The final effluent was inodorous and pale yellow with COD and ammonia nitrogen below 267-1020 mg/L and 6-45 mg/L, respectively. The three-stage AR biofilter had efficient nitrification but relative poor denitrification capacity with a total nitrogen （TN） removal of 58%-73%. The external temperature of AR biofilter did not influence the total ammonia nitrogen removal significantly. It was concluded that the scale-up AR biofilter can work very well and can be a promising technology for the treatment of landfill leachate.

Characterization of refuse landfill leachates of three different stages in landfill stabilization process

Landfill leachates with different ages （mature leachate, 11 years; semi-mature leachate, 5 years; fresh leachate, under operation） were collected from Laogang Refuse Landfill, Shanghai to characterize the colloid size distribution and variations of leachate. These leachates were separated using micro-filtration and ultra-filtration into specific size fractions, i.e., suspended particles （SP） （〉 1.2 μm）, coarse colloids （CC） （1.2-0.45 μm）, fine colloids （FC） （0.45 m, 5 kDa/1 kDa molecular weight （MW））, and dissolved organic matters （DM, 〈 5 kDa/1 kDa MW）. The specific colloids in each size fraction were quantified and characterized through chemical oxygen demands （COD）, total solid （TS）, pH, NH4^＋-N, total organic carbon （TOC） and fixed solid （FS）. It was found that COD, NH^4＋-N and TS in leachate decreased significantly over ages, while pH increased. The dissolved fractions （〈 5 kDa/1 kDa） dominated （over 50%） in three leachates in terms of COD, and the organic matter content in dissolved fraction of leachates decreased and the inorganic matter increased as the disposal time extended, with the TOC/COD ratio 30%-7%. Dissolved fractions decreased from 82% to 40% in terms of TOC as the disposal time extended, suggested that the organic matter remained in leachate would form into middle molecular weight substances during the degradation process.

Occurrence and removal of organic micropollutants in the treatment of landfill leachate by combined anaerobic-membrane bioreactor technology

Organic micropollutants,with high toxicity and environmental concern,are present in the landfill leachate at much lower levels than total organic constituents (chemical oxygen demand (COD),biochemical oxygen demand (BOD),or total organic carbon (TOC)),and few has been known for their behaviors in different treatment processes.In this study,occurrence and removal of 17 organochlorine pesticides (OCPs),16 polycyclic aromatic hydrocarbons (PAHs),and technical 4-nonylphenol (4-NP) in landfill leachate in a comb...

Application of Catalytic Wet Air Oxidation to Treatment of Landfill Leachate on Co/Bi Catalyst

Catalytic wet air oxidation(CWAO) was employed to reduce the organic compounds in landfill leachate and the effects of temperature, oxygen pressure, catalyst dosage, and concentration of the organic compounds on the TOC and COD Cr removal rates were studied. The degradation kinetics of landfill leachate was also investigated and an exponential experiential model consisting of four influential factors was established to describe the reduction of the organic compounds in the landfill leachate. Meanwhile, the GC-MS technique was used to detect the components of the organic intermediates for the inference of the decomposition mechanisms of the organic compounds in landfill leachate. The results reveal that the reaction temperature and the catalyst dosage are the most important factors affecting the degradation reaction of the organic compounds and that the principal intermediates confirmed by GC-MS are organic acids at a percentage of more than 88% with no aldehydes or alcohols detected. The decomposition mechanisms of the organic compounds in landfill leachate were inferred based on the GC-MS information as follows: the activated gas phase O 2 captured the hydrogen of the organic pollutants to produce free radicals, which then initiated the catalytic reaction. So most of the organic compounds were oxidized into CO 2 and H 2O ultimately. In general, catalytic wet air oxidation over catalyst Co 3O 4/Bi 2O 3 was a very promising technique for the treatment of landfill leachate.

Removal of high concentrated ammonia nitrogen from landfill leachate by landfilled waste layer

The landfill of municipal solid waste(MSW) could be regarded as denitrification reactor and involved in ammonia nitrogen biological removal process. In this research, the process was applied to municipal solid waste collected in Shanghai, China, which was characterized by high food waste content. The NH + 4 removal efficiency in the system of SBR nitrifying reactor followed by fresh and matured landfilled waste layer in series was studied. In the nitrifying reactor, above 90% of NH + 4 in leachate was oxidized to NO - 2 and NO - 3. Then high concentrated NO - 2 and NO - 3 were removed in the way of denitrification process in fresh landfilled waste layer. At the same time, degradation of fresh landfilled waste was accelerated. Up to the day 120, 136.5 gC/(kg dry waste) and 17.9 gN/(kg dry waste) were converted from waste layer. It accounted for 50.15% and 86.89% of the total carbon and nitrogen content of preliminary fresh waste, which was 4.42 times and 5.17 times higher than that of reference column respectively. After filtering through matured landfilled waste, BOD 5 concentration in leachate dropped to below 100 mg/L, which would not affect following nitrification adversely. Because the matured landfilled waste acted as a well methanogenic reactor, 23% of carbon produced accumulatively from fresh landfilled waste degradation was converted into CH 4.

Biodegradability enhancement of municipal landfill leachate

The method of enhancing the biodegradability of landfill leachate via air stripping followed by coagulation/ultrafiltration （UF） processes is introduced. In this study, the air stripping process obtained a removal efficiency of 88.6% for ammonia nitrogen （NH3-N）, at an air-to-liquid ratio （A/L） of 3 300 （pH = 11） and after 18 h of stripping. The single coagulation process increased the BOD （biological oxygen demand）/COD （chemical oxygen demand） ratio by 0.089 with a FeCl3 dosage of 570 mg/L, at pH 7.0, and the single UF process increased the BOD/COD ratio from 0.049 to 0.311. However, the combination of coagulation and UF increased the BOD/COD ratio from 0.049 to 0.423, and the final BOD, COD, NH3-N, and colour of the leachate were 1 023 mg/L, 2 845 mg/L, 145 mg/L, and 2 056, respectively, when a 3 kDa molecular weight cut-off （MWCO） membrane was used at an operating pressure of 0.7 MPa. In the ultrafiltration process, the average solution flux （Jv）, concentration multiple （Mc）, and retention rate （R） for the COD were 107.3 L/（m^2·h）, 6.3, and 84.2%, respectively.

Plasma Treatment of Industrial Landfill Leachate by Atmospheric Pressure Dielectric Barrier Discharges

An dielectric barrier discharge （DBD） system in atmospheric pressure utilized for the treatment of industrial landfill leachate is reported. The discharge parameters, such as the operating frequency, gas flow rate, and treating duration, were found to affect significantly the removal of ammonia nitrogen （AN） in industrial landfill leachate. An increase in treating duration leads to an obvious increase in the removal efficiency of AN （up to 83%） and the leachate color changed from deep grey-black to transparent. Thus the dielectric barrier discharges in atmospheric pressure could degrade the landfill leachate effectively. Typical waveforms of both applied voltage and discharge current were also presented for analyzing the discharge processes under different discharge parameters. Optical emission spectra measurements indicate that oxidation species generated in oxygen DBD plasma play a crucial role in removing AN, oxidizing organic and inorganic substances and decolorizing the landfill leachate.

Application Progress of Nanofiltration Combination Technology in the Treatment of Landfill Leachate

Under the impetus of environmental protection policies,the discharge requirements for leachate are becoming more and more stringent.Therefore,the treatment technology of landfill leachate has become a hot research topic at present.In this paper,the chemical composition and water quality characteristics of landfill leachate were briefly introduced,and the characteristics and performance of nanofiltration technology were summarized at first.Afterwards,the recent advances in the application of nanofiltration combination technology in the treatment of landfill leachate at home and abroad were summarized,and the research and application of the combination of membrane separation,chemical coagulation,chemical oxidation and adsorption methods with nanofiltration membrane in the treatment of landfill leachate were mainly introduced.Finally,it is proposed that the combination of nanofiltration technology is feasible and economical,and its reasonable selection and optimization are the directions of future research and have good application prospects.

Research on Treatment of Landfill Leachate Polluting Groundwater by Orthogonal Test

Through PRB simulated device and orthogonal test,we discussed the treatment effect of groundwater polluted by landfill leachate with three reaction mediums of zero-valent iron powder,activated carbon and zeolite. We considered four factors of iron powder mass,activated carbon mass,particle size of iron powder and zeolite mass,and designed a two-level orthogonal test. It concluded that effluent pH appeared to fall or rise as the reaction proceeded,which changed during 7- 8. The removal rates of CODCrin eight reactors were during 60. 7%- 78. 3%,and the removal rates of NH3-N were during 34. 0%- 58. 8%. Activated carbon mass and the interaction of iron powder mass and activated carbon mass had significant influences on the removal of CODCr,while iron powder mass,particle size of iron powder and zeolite mass had insignificant influences on the removal of CODCr. Zeolite mass and activated carbon mass had significant influences on the removal of NH3,while iron powder mass,particle size of iron powder and the interaction with activated carbon mass had insignificant influences on the removal of NH3-N.

Physiochemical and biological characteristics of fouling on landfill leachate treatment systems surface

Fouling of landfill leachate,a biofilm formation process on the surface of the collection system,migration pipeline and treatment system causes low efficiency of leachate transportation and treatment and increases cost for maintenance of those facilities.In addition,landfill leachate fouling might accumulate pathogens and antibiotic resistance genes(ARGs),posing threats to the environment.Characterization of the landfill leachate fouling and its associated environmental behavior is essential for the management of fouling.In this study,physicochemical and biological properties of landfill leachate fouling and the possible accumulation capacity of pathogens and ARGs were investigated in nitrification(aerobic condition)and denitrification(anaerobic condition)process during landfill leachate biological treatment,respectively.Results show that microbial(bacterial,archaeal,eukaryotic,and viral)community structure and function(carbon fixation,methanogenesis,nitrification and denitrification)differed in fouling under aerobic and anaerobic conditions,driven by the supplemental leachate water quality.Aerobic fouling had a higher abundance of nitrification and denitrification functional genes,while anaerobic fouling harbored a higher abundance of carbon fixation and methanogenesis genes.Both forms of leachate fouling had a higher abundance of pathogens and ARGs than the associated leachate,suggesting the accumulation capacity of fouling on biotic pollutants.Specifically,aerobic fouling harbored three orders of magnitude higher multidrug resistance genes mex D than its associated leachate.This finding provides fundamental knowledge on the biological properties of leachate fouling and suggests that leachate fouling might harbor significant pathogens and ARGs.

Bioremediation strategies of palm oil mill effluent and landfill leachate using microalgae cultivation:An approach contributing towards environmental sustainability

Palm oil mill effluent(POME)is defined as the wastewater that contains high concentrations of organics,nutrients and oil and grease generated from the production process of palm oil.Therefore,proper discharge and management of POME is important to avoid deleterious impact on the environment.In fact,solid waste generation is a precursor for its disposal issues as most of the solid waste generated in developing nations is dumped into landfills.This has led to the threat posed by the generation of landfill leachate(LL).LL is a complex dark coloured liquid consisting of organic matter,inorganic substances,trace elements and xenobiotics.Hence,it is essential to effectively treat the landfill leachate before discharging it to avoid contamination of soil,surface&groundwater bodies.Conventional treatment methods comprises of physical,biological and chemical treatment,however,microalgal-based treatment could also be incorporated.Furthermore,with the benefits offered by microalgae in valorisation,the application of microalgae in POME and leachate treatment as well as biofuel production,is considerably viable.This paper provides an acumen of the microalgae-based treatment of POME and LL,integrated with biofuel production in a systematic and critical manner.The pollutants assimilation from wastewater and CO_(2)biosequestration are discussed for environmental protection.Cultivation systems for wastewater treatment with simultaneous biomass production and its valorisation,are summarised.The study aims to provide insight to industrial stakeholders on economically viable and environmentally sustainable treatment of wastewaters using microalgae,and eventually contributing to the circular bioeconomy and environmental sustainability.

Screening of indicator pharmaceuticals and personal care products in landfill leachates: a case study in Shanghai, China

Identifying potential sources of pharmaceuticals and personal care products(PPCPs)in the environment is critical for the effective control of PPCP contamination.Landfill leachate is an important source of PPCPs in water;however,it has barely been involved in source apportionment due to the lack of indicator-PPCPs(i-PPCPs)in landfill leachates.This study provides the first systematic framework for identifying i-PPCPs for landfill leachates based on the wide-scope target monitoring of PPCPs.The number of target PPCPs increased from<20 in previous studies to 68 in the present study.Fifty-nine PPCPs were detected,with median concentrations in leachate samples ranging from below the method quantification limit(MQL)to 41μg/L,and 19 of them were rarely reported previously.A total of 29 target compounds were determined to be PPCPs of high concern by principal component analysis according to multiple criteria,including occurrence,exposure potential,and ecological effect.Coupled with source-specificity and representativeness analysis,erythromycin,gemfibrozil,and albendazole showed a significant difference in their occurrence in leachate compared to other potential sources(untreated and treated municipal wastewater and livestock wastewater)and correlated with total PPCP concentrations;these were recommended as i-PPCPs for leachates.Indicator screening procedure can be used to develop a sophisticated source apportionment method to identify sources of PPCPs from adjacent landfills.

Stable partial nitritation of mature landfill leachate in a continuous flow bioreactor:Long-term performance,microbial community evolution,and mechanisms

A continuous flow bioreactor was operated for 300 days to investigate partial nitritation(PN)of mature landfill leachate,establishing the long-term performance of the system in terms of the microbial community composition,evolution,and interactions.The stable operation phase(31-300 d)began after a 30 days of start-up period,reaching an average nitrite accumulation ratio(NAR)of 94.43%and a ratio of nitrite nitrogen to ammonia nitrogen(NO_(2)^(−)-N/NH_(4)^(+)-N)of 1.16.Some fulvic-like and humic-like compounds and proteins were effectively degraded in anaerobic and anoxic tanks,which was consistent with the corresponding abundance of methanogens and syntrophic bacteria in the anaerobic tank,and organic matter degrading bacteria in the anoxic tank.The ammonia-oxidizing bacteria(AOB)Nitrosomonas was found to be the key functional bacteria,exhibiting an increase in abundance from 0.27%to 6.38%,due to its collaborative interactions with organic matter degrading bacteria.In-situ inhibition of nitrite-oxidizing bacteria(NOB)was achieved using a combination of free ammonia(FA)and free nitrous acid(FNA),low dissolved oxygen(DO)with fewer bioavailable organics conditions were employed to maintain stable PN and a specific ratio of NO_(2)^(−)-N/NH_(4)^(+)-N,without an adverse impact on AOB.The synergistic relationships between AOB and both denitrifying bacteria and organic matter degrading bacteria,were found to contribute to the enhanced PN performance and microbial community structure stability.These findings provide a theoretical guidance for the effective application of PN-Anammox for mature landfill leachate treatment.

Microplastics in landfill leachate:Sources,detection,occurrence,and removal

Due to the accumulation of an enormous amount of plastic waste from municipal and industrial sources in landfills,landfill leachate is becoming a significant reservoir of microplastics.The release of microplastics from landfill leachate into the environment can have undesirable effects on humans and biota.This study provides the state of the science regarding the source,detection,occurrence,and remediation of microplastics in landfill leachate based on a comprehensive review of the scientific literature,mostly in the recent decade.Solid waste and wastewater treatment residue are the primary sources of microplastics in landfill leachate.Microplastic concentration in raw and treated landfill leachate varied between 0-382 and 0-2.7 items L^(−1).Microplastics in raw landfill leachate are largely attributable to local plastic waste production and solid waste management practices.Polyethylene,polystyrene,and polypropylene are the most prevalent microplastic polymers in landfill leachate.Even though the colors of microplastics are primarily determined by their parent plastic waste,the predominance of light-colored microplastics in landfill leachate indicates long-term degradation.The identified morphologies of microplastics in leachate from all published sources contain fiber and fragments the most.Depending on the treatment method,leachate treatment processes can achieve microplastic removal rates between 3%and 100%.The review also provides unique perspectives on microplastics in landfill leachate in terms of remediation,final disposal,fate and transport among engineering systems,and source reduction,etc.The landfill-wastewater treatment plant loop and bioreactor landfills present unique difficulties and opportunities for managing microplastics induced by landfill leachate.