Treatment Of Persistent Organic Pollutants Research Articles

Persistent organic pollutants: Impacts and control measures

Persistent organic pollutants (POPs) represent a significant environmental problem due to their toxicity, with a high capacity to persist in the environment, resistance to conventional degradation methods, the ability to accumulate in living organisms and their magnification in food chains or food. In this review article, the impacts on health and environmental components are examined. Strategies and measures for control, mitigation and/or minimization of POPs are also addressed. Agricultural and industrial activities, inadequate final disposal of solid waste and lack of wastewater treatment are identified as the main sources of POP emissions. In addition, innovative and promising technologies are analyzed, such as nanotechnology, bioremediation, rhizoremediation, biochar, chromatography techniques, ultrasound, among others, for the adequate treatment of POPs. The review highlights both the advantages and limitations of these technologies, pointing out areas that still require developments to achieve effective treatments. More economical and ecological alternatives are also mentioned to counteract the impacts of POPs.

A novel bifunctional particle electrode with abundant Fe/Fe3C and Fe-N-C sites to enhance the performance of electro- in degrading organic pollutant

Electro-Fenton (EF) technology emerges as a promising approach to address the treatment of persistent organic pollutants. Nevertheless, its practical implementation often comes with certain drawbacks, like the low H2O2 activation efficiency, poor pH adaptability, and difficult recycling of the catalysts. To this end, we introduced highly active Fe-N-C sites onto the surface of nitrogen-doped graphene, improved the chemical environment of its central Fe atoms with Fe/Fe3C nanoparticles, effectively regulated the multi-electron oxygen reduction process of the catalyst in the electrochemical reaction, and realized the efficient production and activation of H2O2 in the electro-Fenton process. The synthesized Fe/Fe3C@FeNG-1000 achieved efficient removal of refractory organic pollutants in neutral conditions. The rate constant of degradation for tetracycline hydrochloride (TC) in the electro-Fenton reaction system at pH 7 was recorded as 0.1011 min−1. Additionally, a removal rate of 67.4% for total organic carbon (TOC) was achieved in just 120 min. The treatment of actual wastewater also showed excellent performance, with an average specific energy consumption of 6.16 kWh kg−1 COD−1. Fe/Fe3C@FeNG-1000 can still achieve more than 90% degradation efficiency after 5 consecutive cycles of the experiment, showing excellent stability, and the catalyst can be conveniently retrieved via magnetic methods following the reaction. The results show that the Fe/Fe3C@FeNG-1000-EF system has a wide range of pH applicability, long-term stability and good recyclability, has a good application value in practical wastewater treatment.

Strategies for Organochlorine/Organobromine Removal from Aqueous Environment Using Nanotechnology: A Review

Organohalogens have been discovered since the 1930s and have been used for many applications ever since. The rapid development of industrial activities and reliance on organochlorine/organobromine compounds have further increased their production, ultimately leading to their leakage into our natural environment, where they circulate indefinitely. Exposure to these persistent organic pollutants (POPs) not only results in detrimental effects on human health, such as various cancers, nervous system damage, and liver damage, in addition to fetal and infant growth defects, but also affects fauna, such as bird populations, by depriving them of the ability to reproduce successfully, and farm livestock. The direct consumption of the latter or its derivatives will also lead to the bioaccumulation of POPs in the human body. The POP treatment methods discussed in this review include granular activated carbon (GAC) adsorption, magnetic nanospheres coated with polystyrene, hydrogen peroxide (H2O2), UV, as well as O3 ozonation. The mechanisms, along with the advantages and drawbacks of these methods, were thoroughly discussed. Finally, challenges faced in reducing organochlorine/organobromine pollution were discussed, such as the lack of updates on water quality standards and the list of dangerous pollutants, and the failure to control illegal disposal issues.

Temperature-responsive comprehensive two-dimensional liquid chromatography coupled to high resolution mass spectrometry for the elucidation of the oxidative degradation processes of chemicals of environmental concern

This study explores the possibilities offered by temperature-responsive liquid chromatography (TRLC) based comprehensive 2-dimensional liquid chromatography in combination with reversed-phase liquid chromatography (RPLC) for the analysis of degradation products formed upon oxidative treatment of persistent organic pollutants, in this case exemplified through carbamazepine (CBZ). The TRLC×RPLC combination offers the possibility to overcome peak overlap and incomplete separation encountered in 1D approaches, while the transfer of the purely aqueous mobile phase leads to refocusing of all analytes on the second dimension column. Consequently, this allows for about method-development free and hence, easier LC×LC. The study focuses on the oxidative degradation of CBZ, a compound of environmental concern due to its persistence in water bodies. The TRLC×RPLC combination effectively separates and identifies CBZ and its degradation products, while offering improved selectivity over the individual TRLC or RPLC separations. This allows gathering more understanding of the degradation cascade and allows real-time monitoring of the appearance and disappearance of various degradation products. The compatibility with high-resolution mass spectrometry is last shown, enabling identification of 21 CBZ-related products, nine of which were not previously reported in CBZ degradation studies. The approach's simplicity, optimization-free aspects, and ease of use make it a promising tool for the analysis of degradation pathways in environmental contaminants.

Novel Cerium (IV) Oxide -Ti3C2- titanium dioxide heterostructure photocatalyst for pharmaceutical pollutants removal: Photocatalyst characterization, process optimization and transformation pathways

Tetracycline (TC) is a widely applied antibiotic recognized for its potential negative consequences on human health and ecological balance. In this study, a novel photocatalyst, Cerium (IV) oxide -Ti3C2- titanium dioxide (CeMXT), was synthesized through sonochemical and impregnation techniques, subsequently subjected to comprehensive characterization employing diverse methods including XRD, SEM, TEM, HR-TEM, Raman, XPS, and BET. The optimization of TC degradation was pursued using the Response Surface Methodology (RSM), encompassing variables such as initial TC concentration, irradiation duration, photocatalyst dosage, and pH. The degradation efficacy was investigated through free radical trapping experiments, revealing the pivotal roles of OH and superoxide anion radicals. Remarkable degradation efficiency, reaching 94.70 %, was achieved under specific parameter conditions: 22.19 mg/L TC concentration, 104.13 min irradiation, 0.65 g/L photocatalyst dosage, and pH 4.72. This exceptional performance could be attributed to the elevated generation of oxidant species facilitated by the Z-scheme electron transfer heterojunction. Furthermore, LC-Mass analysis was employed to delineate the intermediates formed during TC photodegradation, culminating in proposing a conceivable degradation pathway. The impressive proficiency of the CeMXT photocatalyst underscores its potential application for effective large-scale treatment of persistent organic pollutants in wastewater treatment facilities. Additionally, comparative analysis with a recently developed photocatalyst highlights its promise as a viable alternative for the remediation of such contaminants in aquatic ecosystems.

Enhanced activation of PMS by a novel MnFe2O4@N-PC-GM composite for rapid 1-naphthol degradation: Formation and mechanism of singlet oxygen

A novel magnetic catalyst, MnFe2O4 functionalized N-doped porous carbon/geopolymer (MnFe2O4 @N-PC-GM) composite, was synthesized using pine cones and geopolymer as precursors for efficient and sustainable removal of 1-naphthol. Experimental results indicated that MnFe2O4 particles were distributed in in the structure of N-PC-GM carrier, greatly increasing the number of active sites. The removal ratio of 1-naphthol was up to 86.06% in MnFe2O4 @N-PC-GM/PMS system, and the degradation process followed pseudo-second-order kinetics (R2 = 0.996). Quenching experiments and EPR analysis validated that 1-naphthol was degraded in MnFe2O4 @N-PC-GM/PMS system mainly through a non-radical oxidation pathway dominated by 1O2. X-ray photoelectron spectroscopy (XPS) and degradation experiments in different gas atmosphere demonstrated that the sources of 1O2 were closely related to the existence of oxygen vacancies (OVs), the conversion of dissolved oxygen as well as the introduction of active sites (N, Mn and Fe). Furthermore, the good degradation rate of 1-naphthol in real water confirmed the feasibility of MnFe2O4 @N-PC-GM/PMS system in practical application. This work provided a new strategy for the treatment of persistent organic pollutants in water.

Application Potential of Layered Double Hydroxides for The Treatment of Persistent Organic Pollutants

Layered double hydroxides (LDHs) is a widely used emerging material. With its adjustable composition, other ions or materials can be incorporated on the surface or in the layer to synthesize modified materials with stronger ability to capture target pollutants. Persistent organic pollutants (POPs) exist in air, water and soil for a long time, which not only affect the ecosystem and ecological balance, but also endanger human health. Therefore, it is of great significance to study the application potential of LDHs in the treatment of POPs. The removal mechanism of persistent organic pollutants by LDHs includes adsorption and activated persulfate oxidation. The factors affecting the removal of POPs by LDHs include the characteristics of LDHs itself (including the inherent characteristics of composition, structure, morphology, etc.), coexisting substrates, temperature, etc.

Activation of chloride by oxygen vacancies-enriched TiO2 photoanode for efficient photoelectrochemical treatment of persistent organic pollutants and simultaneous H2 generation.

Photoelectrochemical (PEC) activation of chloride ions (Cl-) to degrade persistent organic pollutants (POPs) is a promising strategy for the treatment of industrial saline organic wastewater. However, the wide application of this technology is greatly restricted due to the general photoanode activation of Cl- with poor capability, the propensity to produce toxic by-products chlorates, and the narrow pH range. Herein, oxygen vacancies-enriched titanium dioxide (Ov-TiO2) photoanode is explored to strongly activate Cl- to drive the deep mineralization of POPs wastewater in a wide pH range (2-12) with simultaneous production of H2. More importantly, nearly no toxic by-product of chlorates was produced during such PEC-Cl system. The degradation efficiency of 4-CP and H2 generation rate by Ov-TiO2 were 99.9% within 60min and 198.2 μmol h-1 cm-2, respectively, which are far superior to that on the TiO2 (33.1% within 60min, 27.5 μmol h-1 cm-2) working electrode. DFT calculation and capture experiments revealed that Ov-TiO2 with abundant oxygen vacancies is conducive to the activation of Cl- to produce more reactive chlorine species, evidenced by its high production of free chlorine (48.7mgL-1 vs 7.5mgL-1 of TiO2). The as-designed PEC-Cl system in this work is expected to realize the purification of industrial saline organic wastewater coupling with green energy H2 evolution.

Photocatalytic Degradation of Alpha Cypermethrin Based on ZSM-5/TiO2 Hybrid Composites

Zeolite Socony Mobil-5 (ZSM-5) was successfully synthesized by a hydrothermal method from the silicon dioxide (SiO2) precursor prepared from rice husk ash. Titanium dioxide (TiO2) nanoparticles were decorated on ZSM-5 substrate by a sol-gel method. ZSM-5/TiO2 materials were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET) surface area analysis. ZSM-5 was successfully synthesized in crystal structure with an average crystallite size of 3-5 mm. TiO2 nanoparticles with the size of 3-5 nm were distributed on the surface of ZSM-5. ZSM-5/TiO2 materials were used as a photocatalyst to remove alpha – cypermethrin, a kind of the pesticide residues. The results showed that the removal efficiency was 90% with the initial concentration of alpha - cypermethrin of 160 mg L-1. ZSM-5/TiO2 would be a very potential material for using as a photocatalyst for the treatment of persistent organic pollutants.

Assessment of the treatment efficiency of some polycyclic aromatic hydrocarbon (PAHs) in the water by doped TiO2

Treatment of persistent organic pollutants by advanced oxidation processes is a trend nowadays because of its efficiency. Through studies, it has been found that enhanced oxidation processes can treat organic pollutants that are difficult to decompose due to OH radicals and can convert those substances into nontoxic substances which areH2O và CO2. TiO2is a strong oxidizing agent; especially with the addition of catalysts, it is highly likely to be able to to treat persistent pollutants. PAHs are a class of polycyclic aromatic hydrocarbons that are highly toxic and persistent in the environment. The treatment of PAHs with 1% Fe-doped TiO2 coated on silica gel combined with using a 365nm UV lamp model initially produced certain results. Treatment efficiency is up to over 90% after 48 hours. On that basis, the article proposes a feasible solution for the treatment of PAHs in particular and toxic organic substances in general.

Mechanochemical degradation treatment of TBBPA: A kinetic approach for predicting the degradation rate constant

Persistent organic pollutants (POPs) have been banned from production and use. The brominated flame retardant TBBPA is a type of POP and has been widely used in plastics to enhance their fire resistance. However, because the natural degradation of TBBPA is a difficult process, it is particularly important to propose an appropriate treatment method. Hence, the mechanochemical degradation of TBBPA is a feasible method because it does not require high temperature heating and does not produce secondary pollutants after the reaction is completed. In this study, we performed a series of TBBPA degradation experiments with a planetary ball mill and confirmed the degradation efficiency and the rate under various conditions. Then, we conducted a discrete element method (DEM) simulation to compute the collision energies in the ball mill. By comparing the degradation rate and collision energies, we revealed that the mechanochemical degradation rate of TBBPA can be predicted by a normal collision energy computed by DEM simulation. This kinetic approach enables us to predict the rate constant and consequently, the energy consumption for the mechanochemical treatment. The predictability of these parameters will encourage the further application of mechanochemical reaction in the field of POPs treatment.

Photocatalytic membranes: a new perspective for persistent organic pollutants removal.

The presence of conventional and emerging pollutants infiltrating into our water bodies is a course of concern as they have seriously threatened water security. Established techniques such as photocatalysis and membrane technology have proven to be promising in removing various persistent organic pollutants (POP) from wastewaters. The emergence of hybrid photocatalytic membrane which incorporates both photocatalysis and membrane technology has shown greater potential in treating POP laden wastewater based on their synergistic effects. This article provides an in-depth review on the roles of both photocatalysis and membrane technology in hybrid photocatalytic membranes for the treatment of POP containing wastewaters. A concise introduction on POP's in terms of examples, their origins and their effect on a multitude of organisms are critically reviewed. The fundamentals of photocatalytic mechanism, current directions in photocatalyst design and their employment to treat POP's are also discussed. Finally, the challenges and future direction in this field are presented.

Highly efficient metal-free electro-Fenton degradation of organic contaminants on a bifunctional catalyst

Heterogeneous electro-Fenton (e-Fenton) is a promising technology for the treatment of persistent organic pollutants, in which H2O2 is produced via 2e- oxygen reduction and is simultaneously activated into •OH by the iron-based catalyst. This system often suffers from the inevitable metal dissolution in the acidic or even neutral environment, leading to poor pH adaptation and low stability. In this work, we designed a metal-free e-Fenton system, using O-doped carbon nanotubes (OCNTs) as the bifunctional metal-free cathode for the degradation of organic pollutants. The system showed the excellent e-Fenton performance under neutral conditions with the phenol degradation kinetic constant of 0.071 min−1, and the corresponding TOC removal was 76.6% within 300 min. It also exhibited excellent performance for actual coking wastewater treatment with the specific energy consumption of 7.4 kW h kg−1 COD−1, which was lower than that reported heterogeneous electro-Fenton system (9.2–14.4 kW h kg−1 COD−1). The in-situ metal-free e-Fenton system could be regarded as a promising strategy for actual wastewater treatment.

Engineered nanoscale schwertmannites as Fenton–like catalysts for highly efficient degradation of nitrophenols

The Fenton process has been considered as one of the most promising advanced oxidation processes (AOPs) for the treatment of persistent organic pollutants (POPs). Herein, engineered nanoscale schwertmannite (nano–SCH) were fabricated from a PVP (polyvinylpyrrolidone) assisted room–temperature synthesis. The as–prepared well–dispersed nano–SCH materials were further studied as Fenton–like catalysts for 4–nitrophenol (4–NP) degradation in the presence of H2O2. Results showed that the optimized nano–SCH–0.125 was able to degrade 91.0% of 4–NP in 60 min at 298 K, thanks to the nanoscale and hierarchical surface structures that provided abundant reactive sites at solid/solution interfaces. Moreover, mechanism study indicated that •OH radicals were the main reactive species responsible for the excellent 4–NP degradation performances during the Fenton–like processes. This work thus provides a viable pathway to engineer nanoscale materials with enhanced catalytic properties in oxidative degradation of environmental pollutants.

Biosynthesis and characterization of lead selenide semiconductor nanoparticles (PbSe NPs) and its antioxidant and photocatalytic activity

The current study fabricated novel lead selenide nanoparticles (PbSe NPs) by a simple biological benign process with Trichoderma sp. WL-Go. Ultraviolet–visible spectroscopy (UV–vis), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transfer infra-red (FTIR) spectroscopic analysis, Raman spectroscopy and Photoluminescence (PL) were used to characterize the physicochemical properties of the fabricated NPs. Synthesis at pH 8 with 0.5 g biomass of strain WL-Go and (1:1) mM of SeO2: Pb(NO3)2 were the optimal synthesis conditions to achieving 10–30 nm cubic faced centered NPs. The PbSe NPs served as catalyst for investigating the antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and photodegradation ability of rhodamine B dye (10 mg/L). The results indicated that the NPs could eliminate up to 88.60% of free radicals after adding 600 g/mL NPs and could photodegrade 82% of rhodamine B in 30 min. Thus, this study provides new knowledge and strategies for the future use of an environmentally benign bio- catalytic PbSe NPs to efficiently eliminate free radicals and in treatment of persistent organic pollutants in wastewaters.

Degradation of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) by dielectric barrier discharge (DBD) non-thermal plasma: Degradation mechanism and toxicity evaluation

Polychlorinated biphenyls (PCBs) are a kind of persistent organic pollutants (POPs) with stable chemical properties which can be enriched in a biological body for a long time. They are often carelessly released into natural environment and thus constantly posing a potential threat to human health. However, because of lack of effective ways of degrading PCBs, researchers are still striving to explore new approaches to remove them from the environment. In this work, we employed atmospheric-pressure non-thermal dielectric barrier discharge (DBD) plasma to treat 3,3′,4,4′-tetrachlorobiphenyl (PCB77) in aqueous solution and investigated the removal efficiency under different DBD conditions using different discharging gases. As a result, we showed that He-DBD had the highest removal efficiency with hydroxyl radical playing the major role in the degradation, while O2-DBD also gave rise to relatively high efficiency with ozone making an important contribution. After 2 min of treatments by He-DBD and O2-DBD, over 75% of PCB77 was degraded with removal rate of 23.65 mg/L and 22.19 mg/L per minute, respectively. Besides, the toxicological evaluation for the DBD treatment was also provided, confirming that the PCB77 degradation products had negligible biotoxicity. This work therefore provides a new effective approach to treatment of persistent organic pollutants (POPs) in the environment.

Folic acid supplementation reduces multigenerational sperm miRNA perturbation induced by in utero environmental contaminant exposure.

Persistent organic pollutants (POPs) can induce epigenetic changes in the paternal germline. Here, we report that folic acid (FA) supplementation mitigates sperm miRNA profiles transgenerationally following in utero paternal exposure to POPs in a rat model. Pregnant founder dams were exposed to an environmentally relevant POPs mixture (or corn oil) ± FA supplementation and subsequent F1–F4 male descendants were not exposed to POPs and were fed the FA control diet. Sperm miRNA profiles of intergenerational (F1, F2) and transgenerational (F3, F4) lineages were investigated using miRNA deep sequencing. Across the F1–F4 generations, sperm miRNA profiles were less perturbed with POPs+FA compared to sperm from descendants of dams treated with POPs alone. POPs exposure consistently led to alteration of three sperm miRNAs across two generations, and similarly one sperm miRNA due to POPs+FA; which was in common with one POPs intergenerationally altered sperm miRNA. The sperm miRNAs that were affected by POPs alone are known to target genes involved in mammary gland and embryonic organ development in F1, sex differentiation and reproductive system development in F2 and cognition and brain development in F3. When the POPs treatment was combined with FA supplementation, however, these same miRNA-targeted gene pathways were perturbed to a lesser extend and only in F1 sperm. These findings suggest that FA partially mitigates the effect of POPs on paternally derived miRNA in a intergenerational manner.

Persistent organic pollutants (POPs) increase rage signaling to promote downstream cardiovascular remodeling.

Exposure to environmental contaminants and consumption of a high, saturated fatty diet has been demonstrated to promote precursors for metabolic syndrome (hyperglycemia, hyperinsulinemia, and hypertriglyceridemia). The purpose of this study was to determine if exposure to the most prevalent environmental persistent organic pollutants (POPs) would act as causative agents to promote metabolic syndrome independent of dietary intake. We hypothesized that POPs will activate the advanced glycated end‐product (AGE)‐and receptor for AGE (RAGE) signaling cascade to promote downstream signaling modulators of cardiovascular remodeling and oxidative stress in the heart. At 5‐weeks of age nondiabetic (WT) and diabetic (ob/ob) mice were exposed POPs mixtures by oral gavage twice a week for 6‐weeks. At the end of 6‐weeks, animals were sacrificed and the hearts were taken for biochemical analysis. Increased activation of the AGE‐RAGE signaling cascade via POPs exposure resulted in elevated levels of fibroblast differentiation (α‐smooth muscle actin) and RAGE expression indicated maladaptive cardiac remodeling. Conversely, the observed decreased superoxide dismutase‐1 and ‐2 (SOD‐1 and SOD‐2) expression may exacerbate the adverse changes occurring as a result of POPs treatment to reduce innate cardioprotective mechanisms. In comparison, ventricular collagen levels were decreased in mice exposed to POPs. In conclusion, exposure to organic environmental pollutants may intensify oxidative and inflammatory stressors to overwhelm protective mechanisms allowing for adverse cardiac remodeling.

Pilot‐Scale Electrochemical Treatment of a 1,4‐Dioxane Source Zone

AbstractElectrochemical treatment is a promising emerging technology in which direct current is applied to drive the degradation of aqueous contaminants. Several bench‐scale studies have demonstrated the capability of electrochemical oxidation to fully mineralize refractory organics such as pesticides and perfluorinated compounds. However, insights into large‐scale design and field performance are critically lacking. Here, we designed six pilot‐scale reactors and tested their performance and efficiency for the treatment of groundwater contaminated with 1,4‐dioxane (1,4‐DX) at concentrations exceeding 1000 mg/L. Anode surface area‐normalized degradation rates increased with increasing potential applied, while the process was more energy‐efficient per mass unit removed at low potentials. While not all 1,4‐DX was completely mineralized, the detected ring‐opening intermediates are known to be readily biodegradable. Analyses of potential by‐products from chloride oxidation revealed the generation of chloromethanes and perchlorate at low mg/L concentrations. Towards the end of the 8.5‐month pilot test, decreasing currents and degradation rates indicated progressing passivation of the electrodes, likely due to cathodic carbonate precipitation and/or poisoning by the uniquely high organic carbon load of this source zone groundwater. The findings of our study demonstrate that electrochemical groundwater remediation is a capable approach for the treatment of persistent organic pollutants. Our pilot‐scale test provides practitioners with a basis for evaluating its efficiency under site‐specific conditions and collecting critical performance metrics for technology scale‐up.

Effective removal of p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- from landfill leachate using locust bean gum.

The widespread distribution of persistent organic pollutants (POPs) in landfill leachate is problematic due to their acute toxicity, carcinogenicity and genotoxicity effects, which could be detrimental to public health and ecological systems. The objective of this study was to evaluate the effective removal of POPs - namely, p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- - from landfill leachate using locust bean gum (LBG), and in comparison with commonly used alum. The response surface methodology coupled with a Box-Behnken design was employed to optimize the operating factors for optimal POPs removal. A quadratic polynomial model was fitted into the data with the R2 values of 0.97 and 0.96 for the removal of p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl), (S)-, respectively. The physicochemical characteristics of the flocs produced by LBG and alum were evaluated with Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). The infrared spectra of LBG-treated floc were identical with LBG powder, but there was some variation in the peaks of the functional groups, signifying the chemical interactions between flocculants and pollutant particles resulting from POPs removal. The results showed that p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- obtained 96% and 100% removal using 500 mg/L of LBG at pH 4. pH have a significant effect on POPs removal in leachate. It is estimated that treating one million gallons of leachate using alum (at 1 g/L dosage) would cost US$39, and using LBG (at 500 mg/L dosage) would cost US$2. LBG is eco-friendly, biodegradable and non-toxic and, hence, strongly recommended as an alternative to inorganic coagulants for the treatment of POPs in landfill leachate.