Amount Of Sludge Research Articles

Comparative life cycle assessment of sequential chemical and electrochemical processes for the treatment of industrial textile wastewater

AbstractFenton-based processes, chemical and electrochemical, have attracted the interest of industrial and academic researchers for wastewater treatment. However, the deficiency of rigorous comparison between different methods, including assessment of their impact on the environment, has hindered their large-scale application. This study reports for the first time on the sustainability of raw textile wastewater treatment through two sequential processes, Coagulation-Flocculation-Fenton-Neutralization (CF-F-N) and Coagulation-Flocculation-Electro-Fenton-Neutralization (CF-EF-N), based on Life Cycle Assessment (LCA) approach. The CF-F-N and CF-EF-N were optimized at laboratory scale and compared through LCA, using the IPCC-2013 and ReCiPe-2016 midpoint and endpoint methods. The highest CO2 emissions relied on the wastewater primary treatment by CF. This due to the high amount of hazardous sludge generated and the technology necessary for its disposal (i.e., 16.89 kg CO2-Eq/FU for underground deposit in security cells or 47.52 kg CO2-Eq/FU for incineration) as well as the consumption of reagents required for the treatment (alum, 7.72 kg CO2-Eq/FU; and slaked lime, 5.56 kg CO2-Eq/FU). Regarding the sequential processes, the EF-N presented lower carbon footprint (CFP) than the F-N (14.74 kg CO2-Eq/FU vs. 20.74 kg CO2-Eq/FU). Electricity (87.02% of the total CFP) and reagents (88.63% of the total CFP) denoted the main environmental hotspot during the EF-N and F-N, respectively. The EF-N, compared to the F-N, had an inferior incidence in 14 of the 18 impact categories analyzed using the ReCiPe-2016 method at the midpoint level. This is the result of low consumption of reagents and auxiliary chemicals. The electricity was also found as main environmental hotspot of the EF-N. The ReCiPe-2016 method at the endpoint level showed that the EF-N resulted in lower environmental load in all impact categories. The economic performance (11.91 USD/m3 for CF-EF-N vs. 13.66 USD/m3 for CF-F-N) and LCA demonstrated the competitiveness of the electrochemical sequential process compared to the chemical one. The CF-EF-N can be considered more environmentally sustainable technology.

Alkali-activated geopolymers based on calcined phosphate sludges and metakaolin.

The extraction of phosphorite ore in Tunisia has resulted in the discharge of substantial amounts of phosphatic sludge into the region's water system. To mitigate this environmental issue and prevent heavy metal leaching, a geopolymerization process was employed using two types of Tunisian calcined phosphate sludges (Cal-PS1 and Cal-PS2) as substitutes for alkali-activated metakaolin. This study aimed to investigate and compare the physical and mechanical properties of the resulting geopolymers. The optimal substitution ratio of metakaolin with calcined phosphate sludge was determined to be 1.5, equivalent to 20 wt.% of calcined phosphate sludge. Compressive strength tests conducted after 28 days of curing revealed values of 37 MPa for Cal-PS1 specimens and 28 MPa for Cal-PS2 geopolymers while compressive strength of geopolymers soaked in water for 28 days showed a decrease with the addition of phosphate sludges. The specific surface areas of Cal-PS1 geopolymers ranged from 16.3 to 16.9 m2/g and from 17.62 to 18.73 m2/g for Cal-PS2 specimens exhibiting a mesoporous structure. The elasticity modulus of the geopolymers was found to increase with the increase of the apparent density of geopolymers and with the sludges content but it tended to be lower than the Portland cement elasticity modulus. Leaching test was conducted to evaluate the potential environmental applications of the geopolymers. This test demonstrated effective containment of heavy metals within the geopolymers' network, except for low levels of arsenic.

Effect of microwaves combined with peracetic acid to improve the dewatering performance of residual sludge.

The activated sludge process plays a crucial role in modern wastewater treatment plants. During the treatment of daily sewage, a large amount of residual sludge is generated, which, if improperly managed, can pose burdens on the environment and human health. Additionally, the highly hydrated colloidal structure of biopolymers limits the rate and degree of dewatering, making mechanical dewatering challenging. This study investigates the impact and mechanism of microwave irradiation (MW) in conjunction with peracetic acid (PAA) on the dewatering efficiency of sludge. Sludge dewatering effectiveness was assessed through capillary suction time (CST) and specific resistance to filtration (SRF). Examination of the impact of MW-PAA treatment on sludge dewatering performance involved assessing the levels of extracellular polymeric substances (EPS), employing three-dimensional excitation-emission matrix (3D-EEM), Fourier transform-infrared spectroscopy (FT-IR), and scanning electron microscopy. Findings reveal that optimal dewatering performance, with respective reductions of 91.22% for SRF and 84.22% for CST, was attained under the following conditions: microwave power of 600 W, reaction time of 120s, and PAA dosage of 0.25g/g MLSS. Additionally, alterations in both sludge EPS composition and floc morphology pre- and post-MW-PAA treatment underwent examination. The findings demonstrate that microwaves additionally boost the breakdown of PAA into •OH radicals, suggesting a synergistic effect upon combining MW-PAA treatment. These pertinent research findings offer insights into employing MW-PAA technology for residual sludge treatment.

Mechanical and Microstructural Analysis of Lightweight Subgrade Bricks Synthesized from Mixtures of Coal Fly Ash and Sewage Sludge

Abstract The massive discharge of coal fly ash and sewage sludge has placed great pressure on the environment and society. This study proposes a feasible method for producing lightweight subgrade bricks from coal fly ash and sewage sludge. The results show that the lightweight subgrade bricks mainly consist of mullite (3Al2O3·2SiO2), hematite (Fe2O3), sillimanite (Al2SiO5), aluminum phosphate (AlPO4), and a small amount of cristobalite (SiO2). The formation of AlPO4 improved the sintering and mechanical properties of the sintered samples. The formation of voids and cracks in the sintered samples was primarily attributable to the combustion and sintering shrinkage of the organic matter in the mixture. The maximum compressive and flexural strengths were observed when the sewage sludge content was 40 wt. %, and the corresponding compressive strength and flexural strength were 19.86 and 8.57 MPa, respectively. An appropriate amount of sewage sludge improves the connections between coal fly ash particles and promotes the densification of the lightweight subgrade bricks. These results provide a direction for the development of applications for coal fly ash and sewage sludge in the field of building materials.

A method for predicting tank bottom sludge formation during crude oil storage

The laboratory method for predicting the amount and composition of sludge accumulated during crude oil storage on the bottom of a high capacity storage tank has been developed and tested. The laboratory model of the storage tank on a scale of 1:20 was designed with the assumption of a 20-fold acceleration of the process of sedimentation of wax particles and, thus, the formation of a bottom sludge. The results of the model and industrial scale (in the high capacity tank) storage of a Russian export blend crude oil were compared and excellent agreement was found. The developed method was used to evaluate an Iran Light crude oil and a blend of crude oils, Azeri Light, and CPC. The diametrically different behaviour of the compared crude oils during their model storage was ascribed to the different paraffinic particles size distributions and rheologic properties. The correlation between the composition of the crude oil and its tendency to form a sludge at the bottom of the storage tank was not found.

Magneto-optical Properties of Iron-bulk Metallic Glasses Sustainably Produced from Iron-rich Sand Sludge

A large amount of sand sludge (SS) from rivers polluted with heavy metals is continuously dredged and often dumped into landfills, resulting in environmental pollution of soil and water. This work examines the feasibility of the utilization of iron-enriched SS from dredged polluted rivers to produce Fe-based bulk metallic glasses (Fe-BMG). Fe-BMG was prepared from SS by melt-quenching technique, and their magnetic and photochromic properties were studied. The chemical composition of the Fe-BMG was determined by X-ray fluorescence (XRF). The structural properties have been analyzed using the Raman spectroscopy (RS), vibrating sample magnetometer (VSM) and ultraviolet-visible (UV-VIS) spectroscopy. XRF results shows that Fe-BMG contains an iron proportion of 38.8% (wt.) as the hematite (\(\alpha\)-Fe2O3), and magnetite (Fe3O4) phases. The Raman “fingerprints” of \(\alpha\)-Fe2O3 and Fe3O4 were identified at 1330 cm−1, and 300-600 cm-1, respectively. The measured saturation magnetization of Fe-BMG samples is 3.0 emu/g at 60 kOe. A UV-VIS analysis of the Fe-BMG exposed to sunlight simulator reveals an enhanced transmission of light in the 400-700 cm-1 region. These findings confirmed the successful conversion of the hazardous SS into Fe-BMG with promising magneto-optical characteristics for a wide variety of technological applications.

Alternatywne podejście do usuwania/odzyskiwania wybranych metali z wody kopalnianej wypływającej z zalanej kopalni syderytu Nižná Slaná

The objective of this work was the application of innovative method for metals recovery from metalliferous mine water released from the flooded siderite ore deposit Nižná Slaná. Although the metals contained in mine drainage are considered environmental pollutants, they may also be recognised as valuable resources. Several techniques can be used to obtain them by precipitation. Conventional processes using alkaline reagents produce huge amounts of mixed sludge with appropriate storage and management requirement, void of possibility of individual metals subsequent processing. This study examined the feasibility of Fe and Mn selective retrieval from real mine water. After oxidation and partial precipitation of iron using hydrogen peroxide, precipitation by sodium hydroxide was applied to the residue iron removal from mine water. In the next step potassium permanganate was used to eliminate manganese by oxidative precipitation. ORP and pH values of processed mine water was recorded in the course of oxidation/precipitation processes. The morphology and elemental composition of obtained products were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The recovery efficiencies of Fe and Mn from mine water reached 99.87 % and 99.25%, respectively. Target metals were removed with high selectivity to levels that comply with environmental requirements.

Evaluation of the Heavy Metals Content in Sewage Sludge from Selected Rural and Urban Wastewater Treatment Plants in Poland in Terms of Its Suitability for Agricultural Use

The amount of sewage sludge produced in Poland is increasing every year. Once stabilised and hygienised, sewage sludge is a valuable product, rich in biogenic elements such as nitrogen and phosphorus, which are essential for plant growth. However, in addition to the compounds that are beneficial to the soil, this sludge can also contain harmful substances such as heavy metals. The aim of this assessment is to analyse the content of seven heavy metals in sewage sludge from urban and rural wastewater treatment plants (WWTPs) located in Poland. This analysis allows for the suitability of sludge from the studied wastewater treatment plants for natural management to be assessed. The concentration ranges of Cd, Cu, Ni, Pb, Zn, Cr, and Hg in sludge samples from rural wastewater treatment plants were 0.6–9.5, 9.3–524, 4.8–90.0, 8.8–275.2, 575–1732, 7.5–170.0, and 0–3.8 mg/kg dry matter, respectively. In sludge samples from urban wastewater treatment plants, the concentration ranges of Cd, Cu, Ni, Pb, Zn, Cr, and Hg were 1.07–16.7, 32–195, 1.3–128.9, 21.2–322.4, 20–5351.1, 12.7–2759.8, and 0.1–1.55 mg/kg dry matter, respectively. Only one of the analysed wastewater treatment plants (Skarżysko-Kamienna) exceeded the limit values.

Resource utilization of sewage sludge as a nitrogen self-doped carbon quantum dot for specific detection of Fe3+ and Hg2+

With the widespread application of sewage biological treatment technology, a large amount of sewage sludge is generated during the sewage treatment process, which not only poses a threat to the environment but also results in wastage of C and N resources. In this study, the nitrogen self-doped fluorescent carbon dots (N-CDs) with an average particle size of 3.43 nm were synthesized green through a two-stage hydrothermal method. It was found that N-CDs can detect Fe3+ through internal filtration effect (IFE), with a linear detection range of 0–250 μM and a detection limit of 2.207 μM. Furthermore, N-CDs can also serve as a “turn off–on” probe for monitoring Hg2+, with a linear detection range of 2–10 μM and a detection limit of 0.989 μM. Interestingly, oxygen-containing groups were shown to be sensitive to Hg2+, which has been demonstrated for the first time. Moreover, the practical application of N-CDs as a double ion sensor in the detection of Fe3+ and Hg2+ has achieved good results for real power plant wastewater.

THE IMPACT OF GLASS AND CONCRETE SLUDGE AMOUNTS ON THE PROPERTIES OF SUSTAINABLE CONCRETE WITH A CRYSTALLISING ADMIXTURE

THE IMPACT OF GLASS AND CONCRETE SLUDGE AMOUNTS ON THE PROPERTIES OF SUSTAINABLE CONCRETE WITH A CRYSTALLISING ADMIXTURE

Solventless recovery of lipids from urban sewage sludge: How to sustainably turn a waste into a valuable source of oleochemicals

For the first time, the recovery of lipids from urban sewage sludge was investigated through a solvent-free process based on elementary operations validated on a pilot scale (2 tons per hour). Sedimented sewage sludge was dewatered through centrifugation, acidified (and in the case treated with hydrogen peroxide), heated to 80 °C and centrifuged to obtain three different streams: i) raw grease, ii) exhausted aqueous phase, and iii) dewatered sludge.The recovery yield of grease from sludge could reach a very high value (70 wt%), depending essentially on the initial lipid content in sewage sludge, which was monitored and found to range between 1.1 and 6.6 wt% (13–25 wt% with respect to TS). The use of H2O2 played a crucial role in the recoverability of lipids and the relevant pureness in free fatty acids content (>89 wt%). In addition, the total solids content in the exhausted aqueous phase and the final residual sludge were sensibly affected by using H2O2. Final dewatered sludge had a very high content of solids (TS 31.0 ± 2.3 wt%) and resulted in 15 % less of the amount of sludge conventionally obtained from anaerobic digestion. According to these figures, for medium wastewater treatment plants, a selling price of 800–900 Euro per ton of grease would guarantee a return on investments within three years of operations. This simple procedure represents a quick and proficient way to treat sewage sludge, turning it into a valuable feedstock for fine chemicals, in agreement with Circular Bioeconomy principles.

Comparative life cycle assessment of landfill sludge treatment technologies in China.

Reasonable treatment of large amounts of sludge excavated from landfills has gained increasing attention due to the diminishing availability of landfill space in China. In this study, five landfill sludge (LS) treatment technologies using life cycle assessment (LCA) and life cycle cost (LCC) were investigated, i.e., co-incineration in coal-fired power plants (CFPP) and waste incineration power plant (WIPP), co-processing in cement kiln, bricks production, and sintering ceramsite. The LCA results demonstrate that sintering ceramsite outperforms other technologies and LCC results indicate sintering ceramsite also provides the highest economic benefit ($869.94). To further enhance environmental and economic performances of the LS treatment, the substitution of coal with natural gas and biomass can reduce Energy Conservation and Emission Reduction (ECER) index by 74% and 98%, respectively. This substitution can increase economic returns by 24% and 26%, respectively. Furthermore, national-level economic benefit and carbon emission reduction potential of different LS treatment technology alternative scenarios were assessed. Results display that a combination of 50% CFPP, 25% bricks, and 25% ceramsite (biomass) offers the highest economic gain, which is 3.02 times that of 50% CFPP and 50% cement (original case). Conversely, the replacement of 25% brick with 25% cement in the above combination result in the lowest carbon reduction, which is 9.35 times that of the original case.

Microstructure, durability and surface free energy of lightweight aggregate modification of sanitary ceramic wastes and sewage sludge

The research on the durability and physical properties of lightweight aggregate (LWA) with addition of sanitary ceramic wastes and sewage sludge was presented in the paper. The following characteristics of LWA were defined: contact angle (CA), absorptivity, roughness, surface free energy (SFE) before and after the UV radiation durability test, thermal conductivity coefficient λ, compressive strength, freezing-thawing, salt resistance and others. Open porosity was examined using computed tomography, it reached 20.987 % for the ceramic waste aggregate, and 7.023 % for the reference aggregate. The aggregate with the largest amount of ceramic waste (20 %) and sewage sludge (10 %) has the highest average roughness (Ra), which is 14 % higher than the Ra of the reference aggregate. The contact angle decreased by almost 4 times and samples had higher absorptivity (19.994 %) when 10 % sewage sludge and 20 % sanitary ceramic were added to the aggregate. The sanitary ceramic waste application may enhance the poor durability characteristics of lightweight aggregate with/without sewage sludge. Replacing natural loess with sanitary ceramic waste material brings benefits both in terms of respect for natural resources and also improves the properties of lightweight aggregates.

Behavior of PCDD/Fs and PCBs from Wastewater Treatment Plants during Sewage Sludge Composting: Study of Semi-Anaerobic Conditions and Different Stages of the Process

Composting is a common treatment for the high amounts of sewage sludge produced in wastewater treatment plants, and the product is used in agriculture. Composting reduces the levels of biodegradable organic pollutants, although other compounds present in wastewater and not eliminated previously by conventional physical–chemical and chemical treatments, such as polychorodibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs), have been found in the final compost at higher levels than those observed in the initial sludge. Their formation was studied during composting under unfavorable aeration conditions and paying attention to different stages of the process. Experiments were carried out in small vessels inside a controlled oven for three types of sewage sludge. Pentachlorophenol was previously added as a dioxin precursor. A clear formation of PCDD/Fs was found, especially during the maturation stage for two experiments. Mainly octachlorodibenzo-p-dioxin (OCDD) and 1234678-heptachlorodibenzo-p-dioxin (1234678-HpCDD) to a lesser extent were formed. OCDD levels in the final samples were around 10 times higher than those of the initial mixture after removing the concentration effect. No clear formation nor degradation of PCBs was observed. The toxicity values due to PCDD/Fs and PCBs found in the initial mixtures were 1.20–2.46 ng WHO-TEQ/kg, and those from the final samples were 2.30–7.86 ng WHO-TEQ/kg. Although the toxicity values are below the most restrictive limits found in Europe in this case, toxicity could increase considerably with the presence and concentration of other precursors. Compost from sewage sludge is an ecological product, but the operating conditions must be controlled to avoid PCDD/F formation and facilitate degradation of persistent organic pollutants.

Utilizing magnetic nanoparticles embedded into polyvinyl alcohol and sodium alginate for the absorption of arsenic

Arsenic is an extremely toxic metalloid. The majority of arsenic water pollution originates from industrial activities such as mining, smelting, and utilization of arsenic compounds in glass, pigment, semiconductor, and other industries. Arsenic-containing wastewater poses a threat to groundwater, freshwater, seawater, and soil. Bioaccumulation of arsenic as a result of accidental ingestion may have a harmful effect on the skin and cardiovascular, respiratory, and nervous systems, thereby posing a major health risk. Chemical coagulation, membrane filtration, and adsorption can be used to treat arsenic-containing wastewater. However, chemical coagulation produces a large amount of waste sludge, which is harmful and incurs high processing costs. Membrane filtration is difficult to adopt because of its high operation and maintenance costs. Adsorption is an inexpensive, easy-to-use, sludge-free water treatment method that enables adsorbent recycling. These characteristics make adsorption an economically feasible technique for water treatment. Magnetic nanoparticles (MNPs) are small particles with a high surface area to volume ratio. Their strong magnetic properties enable them to absorb specific water pollutants. MNPs are currently used as water treatment adsorbents. However, they have several drawbacks, including low acid and alkali buffer capacity and water oxidation. In this study, MNPs immobilized with polyvinyl alcohol (PVA) and sodium alginate (SA) were used to enhance the efficacy of wastewater treatment with magnetic materials. These modified MNPs exhibited magnetic characteristics and improved acid resistance. When 100 g/L PVA/SA-MNPs (pH 1–6) were stirred at 120 rpm for 30 min, the resulting iron concentration of the water was 16 mg/L. By contrast, the MNPs released iron in levels ranging from 18 to 4045 mg/L. The PVA/SA–MNPs efficiently adsorbed arsenic in the pH range 3–6, with a high removal efficiency of 76%–82%. At pH 5, the average adsorption capacity was 382 ± 27 μg/g. To recover the MNPs, they were rinsed with deionized water and immersed in acid three times, after which their adsorption capacity was 300 μg/g or higher. By contrast, the PVA/SA-MNPs could be recovered through spontaneous sedimentation, eliminating the need for a magnetic field and simplifying the collection process. In addition, iron dissolution in acidic solutions was minimized for the PVA/SA-MNPs, contributing to environmental protection.

Investigation on manhole sludge in Can Tho City

During the rainy season, Can Tho city frequently faces severe flooding on its streets. In this study, the investigation is carried out on 30 streets and 10 canals nearby the streets in the center of Can Tho city. The results indicate that the surveyed manholes contain a lot of sludge with an average volume percent of 39.29%. In the food service areas, the average volume percent of sludge in manholes is found more than 70%. In the concentrated residential areas, the amount of sludge is less, but still at a relatively high rate (over 50%). In addition, the results show that the studied canals in the inner city are polluted due to waste directly from the drainage system. These issues have an effect on the drainage capacity of the roads. Some discussion on sand also shows that the sand shortage has reached an alarming level, which is the main factor leading to slow progress of some road projects. The sand reserves in the Mekong Delta region decrease sharply and the scarcity of sand causes sand prices to skyrocket, which is a difficult problem for this area. The development of mobile sludge treatment technology to produce a replacement material suitable for levelling and fertilizer purposes can be a potential topic for future research.

Recovery of nutrients from fish sludge to enhance the growth of microalga Chlorella sorokiniana CMBB276

Intensive aquaculture production generates large amounts of sludge. This waste could be considered as a potential source of nutrients that can be recovered and utilized. Little attention has been paid to nutrient recovery from fish sludge. In this study, bioconversion of sludge was evaluated in lab scale under anaerobic (AN), facultative anaerobic (FA) and aerobic (AE) conditions. After 40 days of fermentation, AN recovered the highest values of dissolved total nitrogen (82.7 mg L−1), while AE showed the highest dissolved total phosphorus (11.8 mg L−1) and the highest reduction of total suspended solids (36.0 %). Microbial analysis showed that AN exhibited a distinct bacterial community than that of FA and AE. Furthermore, C. sorokiniana grown in AN effluents collected after 12 days of fermentation achieved the highest biomass production (1.96 g L−1). These results suggest that AN has the best potential to recover nutrients from sludge for production of C. sorokiniana.

Recovery of valuable metals from manganese purification sludge (SPS) containing Mn-Ni-Co sulfide and preparation of battery-grade Ni-Co-Mn sulfate solution

The manganese production industry produces a large amount of sulfide purification sludge (SPS) every year, representing a hazardous solid waste but also a valuable secondary resource for Ni, Co, and Mn. In this paper, the recovery of Ni, Co, and Mn from the SPS was achieved by (i) leaching with a solution of hydrogen peroxide, (ii) selectively extracting nickel, cobalt and manganese, (iii) solvent extraction for zinc removal, and finally obtained the battery-grade Ni-Co-Mn sulfate solution. During the hydrogen peroxide solution leaching stage, the leaching efficiency of Co, Mn, and Ni reached 98.5%, 98.6%, and 95.6%, respectively. A synergistic extraction system (SES) consisting of decyl 4-picolinate and dinonylnaphthalene sulfonic acid was used to selectively extract Ni, Co, and part of Mn, and the extraction of Ni and Co was >99.8% and 95.5%, respectively. The loaded organic was subjected to four-stage countercurrent scrubbing using a 5 g/L H2SO4 solution, resulting in nearly 100% removal of Ca and Mg. After that, 150 g/L H2SO4 was used to strip Ni, Co, and Mn from the loaded organic to obtain a crude Ni-Co-Mn sulfate solution. Finally, D2EHPA was utilized for the extraction of impurity Zn from the stripping solution to obtain a battery-grade Ni-Co-Mn sulfate solution with <5 × 10−4 g/L of Zn. Compared to traditional technology, the novel process not only enables the recovery of valuable Ni, Co, and Mn in SPS but also facilitates their direct preparation into battery-grade nickel‑cobalt‑manganese sulfate solution, which has the advantages of a short process and high added value.

Study on COD and color removal efficiency in textile dyeing wastewater by iron electro-coagulation technology combined with persulfate

Electrocoagulation (EC) is an attractive method for treating many types of wastewater due to its advantages. The purpose of this study is to investigate the effect of persulfate addition on the efficiency of textile wastewater treatment through the removal percentage of COD and color parameters. Persulfate is proven to significantly enhance the rate and efficiency of pollutant removal in textile wastewater. The removal percentage of COD could reach 91.33 ± 1.23% and 97.99% ± 0.52% was the highest removal percentage of the color parameter at the optimal reaction parameters. The effluent concentration meets the standards according to Vietnam national technical regulation on textile industry wastewater. By using persulfate, the COD and color removal efficiency increased by 17.53 ± 2.69% and 8.81 ± 0.91%, respectively, compared to the single electrocoagulation process. The amount of sludge generated in the system is 0.542 ± 0.0357 kg/m3, significantly reduced compared to the flocculation process of 0.875 ± 0.0295 kg/m3.

Sustainable approach of biological treatment of landfill leachate by Anaerobic Ammonium Oxidation: A review

An upsurge in living standards, rising industrialization and urbanization, the protection of water environment has become a priority. Anaerobic ammonium oxidation process has drawn a lot of attention since it demonstrated substantial advantages over conventional nitrogen removal techniques, including a 100% reduction in the amount of organic carbon required, a 60% reduction in the amount of aeration needed, and a 90% reduction in the amount of sludge produced. Effective treatment of landfill leachate is extremely important as leachate is a threat to the environment. Municipal waste management is still a challenging situation in developing countries. Uncontrolled waste disposal results in greenhouse gases emissions which worsens climate change as the leachate will pollute water bodies, soil and a significant air pollution which impacts on human health will be released. This paper reviewed several published research works in Scopus dealing with the leachate treatment by Anammox process combined with some other systems and highlighted some common challenges found with the application of this new technology. Treating landfill leachate resulted in an excellent ammonium NH4 +-N removal efficiency. However, it has been highlighted that most of the research reviewed reported some limitations of the technology on a small scale such as the low start-up time affecting the growth of bacteria in the reactors and the instability of the system when pH and temperature decrease. Biological treatment, Anammox method included, offers a cost-effective, eco-friendly, and an effective solution for nitrogen removal.