In this study, biochar derived from spent coffee grounds (SCGB) was used to adsorb norfloxacin (NOR) in water. The biochar properties were interpreted by analysis of the specific surface area, ...morphology, structure, thermal stability, and functional groups. The impacts of pH, NOR, and ion's present on SCGB performance were examined. The NOR adsorption mode of SCGB is best suited to the Langmuir model (R2 = 0.974) with maximum absorption capacity (69.8 mg g−1). By using a Response Surface Method (RSM), optimal adsorption was also found at pH of 6.26, NOR of 24.69 mg L−1, and SCGB of 1.32 g L−1. Compared with biochars derived from agriculture such as corn stalks, willow branches, potato stem, reed stalks, cauliflower roots, wheat straw, the NOR adsorption capacity of SCGB was 2–30 times higher, but less than 3–4 times for biochars made from Salix mongolica, luffa sponge and polydopamine microspheres. These findings reveal that spent coffee grounds biochar could effectively remove NOR from aqueous solutions. Approaching biochar derived from coffee grounds would be a promising eco-friendly solution because it utilizes solid waste, saves costs, and creates adsorbents to deal with emerging pollutants like antibiotics.
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•Norfloxacin was removed using biochar derived from spent coffee grounds (SCGB).•pH significantly influenced the Norfloxacin (NOR) adsorption of the SCGB.•Based on Langmuir model, the maximum absorption capacity was 69.8 mg g−1 at pH 6.•The adsorption process was optimized by using the response surface methodology.•Optimal adsorption conditions were achieved at pH of 6.26 and SCGB of 1.32 g L−1.
This article provides a comprehensive review on aerobic composting remediation of soil contaminated with total petroleum hydrocarbons (TPHs). The studies reviewed have demonstrated that composting ...technology can be applied to treat TPH contamination (as high as 380,000 mg kg−1) in clay, silt, and sandy soils successfully. Most of these studies reported more than 70% removal efficiency, with a maximum of 99%. During the composting process, the bacteria use TPHs as carbon and energy sources, whereas the fungi produce enzymes that can catalyze oxidation reactions of TPHs. The mutualistic and competitive interactions between the bacteria and fungi are believed to sustain a robust biodegradation system. The highest biodegradation rate is observed during the thermophilic phase. However, the presence of a diverse and dynamic microbial community ensures that TPH degradation occurs in the entire composting process. Initial concentration, soil type, soil/compost ratio, aeration rate, moisture content, C/N ratio, pH, and temperature affect the composting process and should be monitored and controlled to ensure successful degradation. Nevertheless, there is insufficient research on optimizing these operational parameters, especially for large-scale composting. Also, toxic and odorous gas emissions during degradation of TPHs, usually unaddressed, can be potential air pollution sources and need further insightful characterization and mitigation/control research.
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•Composting is technically robust and cost-effective for TPH degradation.•Microbial activity determines the success of composting.•Moisture content and aeration rate are decisive operational parameters.•Gas emissions from composting should be mitigated to avoid secondary pollution.
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•Phthalates have been globally detected in the environment matrices.•Phthalates can cause human health risks via exposure pathways.•Aerobic biodegradation of phthalates is higher ...efficiency than anaerobic.•Heterotrophic and ammonia-oxidizing bacteria plays a major role in biodegradation.•Membrane bioreactor is robust to remove phthalates with high efficiency.
Phthalates are well-known emerging contaminants that harm human health and the environment. Therefore, this review aims to discuss about the occurrence, fate, and phthalates concentration in the various environmental matrices (e.g., aquatic, sediment, soil, and sewage sludge). Hence, it is necessary to treat sources containing phthalates before discharging them to aqueous environment. Various advanced wastewater treatments including adsorption process (e.g., biochar, activated carbon), advanced oxidation processes (e.g., photo-fenton, ozonation, photocatalysis), and biological treatment (membrane bioreactor) have been successfully to address this issue with high removal efficiencies (70–95%). Also, the degradation mechanism was discussed to provide a comprehensive understanding of the phthalate removal for the reader. Additionally, key factors that influenced the phthalates removal efficiency of these technologies were identified and summarized with a view towards pilot-scale and industrial applications.
Acetaminophen (ACT) is commonly used as a counter painkiller and nowadays, it is increasingly present in the natural water environment. Although its concentrations are usually at the ppt to ppm ...levels, ACT can transform into various intermediates depending on the environmental conditions. Due to the complexity of the ACT degradation products and the intermediates, it poses a major challenge for monitoring, detection and to propose adequate treatment technologies. The main objectives of this review study were to assess (i) the occurrences and toxicities, (2) the removal technologies and (3) the transformation pathways and intermediates of ACT in four environmental compartments namely wastewater, surface water, ground water, and soil/sediments. Based on the review, it was observed that the ACT concentrations in wastewater can reach up to several hundreds of ppb. Amongst the different countries, China and the USA showed the highest ACT concentration in wastewater (≤300 μg/L), with a very high detection frequency (81–100%). Concerning surface water, the ACT concentrations were found to be at the ppt level. Some regions in France, Spain, Germany, Korea, USA, and UK comply with the recommended ACT concentration for drinking water (71 ng/L). Notably, ACT can transform and degrade into various metabolites such as aromatic derivatives or organic acids. Some of them (e.g., hydroquinone and benzoquinone) are toxic to human and other life forms. Thus, in water and wastewater treatment plants, tertiary treatment systems such as advanced oxidation, membrane separation, and hybrid processes should be used to remove the toxic metabolites of ACT.
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•China and the USA showed the highest acetaminophen (ACT) concentration.•Advanced oxidation processes (AOPs) removed ACT to the ppt level.•More than 20 by-products and intermediates of ACT were detected.•Treated wastewater was not totally free from the toxic effects due to ACT metabolites.
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•Microalgae:activated sludge ratio (3:1) was the optimum co-culture operation.•Microalgae played a vital role in biomass production and nutrient removal.•Under the optimum ratio, COD ...removal was obtained 98% in 4 days.•Biological assimilation majorly contributed to nutrient removal in the co-culture PBR.
In this study, mixed culture (microalgae:activated sludge) of a photobioreactor (PBR) were investigated at different inoculation ratios (1:0, 9:1, 3:1, 1:1, 0:1 wt/wt). This work was not only to determine the optimal ratio for pollutant remediation and biomass production but also to explore the role of microorganisms in the co-culture system. The results showed high total biomass concentrations were obtained from 1:0 and 3:1 ratio being values of 1.06, 1.12 g L-1, respectively. Microalgae played a dominant role in nitrogen removal via biological assimilation while activated sludge was responsible for improving COD removal. Compared with the single culture of microalgae, the symbiosis between microalgae and bacteria occurred at 3:1 and 1:1 ratio facilitated a higher COD removal by 37.5–45.7 %. In general, combined assessment based on treatment performance and biomass productivity facilitated to select an optimal ratio of 3:1 for the operation of the co-culture PBR.
Herein, a sponge membrane bioreactor (Sponge-MBR) combined with ozonation process was performed to remove the antibiotics which frequently existed in the hospital wastewater. Whilst seven antibiotics ...i.e., norfloxacin, ciprofloxacin, ofloxacin, sulfamethoxazole, erythromycin, tetracycline and trimethoprim were widely used in medications, this integration was applied for the evaluation of treatment performance under different fluxes. As the results, whilst the antibiotics were eliminated about 45–93%, the tetracycline was completely removed (100%) using Sponge-MBR operated at the flux of 10 LMH. For enhancement of antibiotics removal, the ozonation process was introduced to treat the membrane permeate. Overall efficiencies were 97 ± 2% (trimethoprim), 92 ± 4% (norfloxacin), 90 ± 1% (erythromycin), 88 ± 4% (ofloxacin), 83 ± 7 (ciprofloxacin) and 66 ± 1% (sulfamethoxazole). These results demonstrated Sponge-MBR coupled with ozonation could be a prospective technology for the hospital wastewater treatment.
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•Sponge membrane bioreactor-ozonation was introduced to antibiotics removal.•High removal efficiencies were achieved for antibiotics, except sulfamethoxazole.•Ozonation enhanced sulfamethoxazole removal efficiency up to 66%.•Organics and nitrogen were significantly eliminated by Sponge membrane bioreactor.
The quest for a chemical surfactant substitute has been fuelled by increased environmental awareness. The benefits that biosurfactants present like biodegradability, and biocompatibility over their ...chemical and synthetic counterparts has contributed immensely to their popularity and use in various industries such as petrochemicals, mining, metallurgy, agrochemicals, fertilizers, beverages, cosmetics, etc. With the growing demand for biosurfactants, researchers are looking for low-cost waste materials to use them as substrates, which will lower the manufacturing costs while providing waste management services as an add-on benefit. The use of low-cost substrates will significantly reduce the cost of producing biosurfactants. This paper discusses the use of various feedstocks in the production of biosurfactants, which not only reduces the cost of waste treatment but also provides an opportunity to profit from the sale of the biosurfactant. Furthermore, it includes state-of-the-art information about employing municipal solid waste as a sustainable feedstock for biosurfactant production, which has not been simultaneously covered in many published literatures on biosurfactant production from different feedstocks. It also addresses the myriad of other issues associated with the processing of biosurfactants, as well as the methods used to address these issues and perspectives, which will move society towards cleaner production.
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•Effects of artificial and natural lighting on photobioreactors were investigated.•COD removal of artificial lighting mode was 13.2% higher than that of natural one.•Nutrients removal ...between two lighting conditions were not significantly different.•Light intensity had strong positive correlation with biomass and DO concentration.•Natural lighting saved 57% energy consumption compared with artificial lighting.
Co-culture using microalgae-activated sludge in Sequencing Batch Photobioreactors (PBRs) was investigated for wastewater treatment performance. This study evaluated the effect of natural and artificial lighting conditons on treatment performance under consideration of energy consumption. The results found that the removal of nutrients and COD of natural lighting condition was only 10% and 13% lower than those of artificial lighting respectively. Generally, artificial lighting mode took an advantage in pollutants removal. However, standing at 0.294 kWh L-1, the total energy consumption of natural lighting was over two times less than that of artificial lighting. It reveals the natural lighting system played a dominant role for cutting energy costs significantly compared to artificial lighting one (∼57%). As a practical viewpoint on energy aspect and treatment performance, a natural lighting PBR system would be a sustainable option for microalgae-activated sludge co-culture system treating wastewater.
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•Simultaneous recovery of phosphorus and potassium from urine was achieved.•Recovery of P and K reached 98.4% and 70.5%, respectively at low Mg:K ratio of 1.25.•K-struvite pellets ...recovered have low water content and high purity (>95%).•The fluidized bed homogeneous crystallization (FBHC) was performed without seeds.•FBHC recovery can help yield a profit of $0.26/m3-urine.
Most of nutrients in municipal wastewater originate from human urine. In this study, a novel fluidized-bed homogeneous crystallization process was developed for the simultaneous recovery of phosphorus (P) and potassium (K) from synthetic human urine. The operational variables including pH, Mg:K ratios and up-flow velocity were tested in the laboratory. The total removal of P and K (TR%) reached 98.4% and 70.5%, respectively, and the crystallization ratios (CR%) were 86.5% and 62.3%, respectively, at conditions of pH 10 ± 0.2, molar ratio Mg:K = 1.25, initial concentrations 850 mg P/L and 1830 mg K/L. The SEM and XRD analyses showed that the fluidized bed homogeneous crystallization (FBHC) product was pure magnesium potassium phosphate (K-struvite) (average size = 0.85 mm; purity = 95 ± 3%). The modelling of minimum fluidization velocity (MFV) resulted in values of up-flow 1.5–2.0 times the MFV for the effective fluidization. The profit of the recovery of P and K from human urine via FBHC process could be $0.26/m3-urine.
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