Tertiary Treatment Research Articles

Toxicity of Silver Nanoparticles Synthesized from Opuntia ficus-indica on Danio rerio and Arabidopsis thaliana and Their Antimicrobial Activity

Silver nanoparticles (AgNPs) usefulness has been widely demonstrated in fields such as agriculture, medicine, food, and pharmaceutical industries, primarily for their antibacterial properties. AgNPs synthesized from biological extracts are as effective as those obtained by chemical methods, with the advantage that in the former fewer toxic compounds are generated for the environment. In a previous work, we synthesized AgNPs from the aqueous extract of Opuntia ficus-indica fruit peel (OfAgNPs) and tested their activity against microorganisms from a wastewater treatment plant. OfAgNPs were proposed for use as tertiary wastewater treatment; however, more needs to be known about their antimicrobial activity and toxicological potential. In the present study, the antimicrobial effect of OfAgNPs was demonstrated against reference bacterial strains of Escherichia coli (DH5α), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus (ATCC 29213), and against fungi isolated in the laboratory and identified as Aspergillus sp., Colletotrichum sp., and Cladosporium sp. In addition, in this work, we report the effects of OfAgNPs produced by exposure in two model organisms: a fish, Danio rerio, and a plant, Arabidopsis thaliana. OfAgNPs in A. thaliana caused negative effects on growth and photosynthetic pigment content only when the exposure was constant and greater than 6 mg/L. However, in D. rerio, impaired caudal fin development was observed at 0.15 mg/L from 24 hr of exposure. This is evidence of the toxicological potential of OfAgNPs, so their use should be carried out in a controlled manner.

How to choose the best tertiary treatment for pulp and paper wastewater? Life cycle assessment and economic analysis as guidance tools

Pulp and paper wastewater (P&P WW) often requires tertiary treatment to remove refractory compounds not eliminated by conventional biological treatment, ensuring compliance with high-quality effluent discharge or reuse standards. This study employs a life cycle assessment (LCA) methodology to compare alternative tertiary treatment technologies for P&P WW and rank them accordingly. The evaluated technologies in the scenarios include inorganic (S1) and organic (S2) coagulation-flocculation, ozonation (O3) (S3), O3+granular activated carbon (GAC) (S4), and ultrafiltration (UF)+reverse osmosis (RO) (S5). The analysis focuses on a P&P wastewater treatment plant (WWTP) in Northeastern Italy. The LCA is complemented by an economic analysis considering each technology's capital and operating costs, as well as potential revenues from internal effluent reuse. Results indicate that S4 (O3+GAC) outranks all the other scenarios in terms of both environmental performance and economic viability, primarily due to the advantages associated with effluent reuse. S5 (UF+RO), which also involves reuse, is limited by the high energy consumption of UF+RO, resulting in increased environmental impacts and costs. The physicochemical scenario S2 (Chem Or), currently utilized in the WWTP under study, remains the best-performing technology in the absence of effluent reuse. In contrast, S3 (O3 alone) exhibits the poorest environmental and economic outcomes due to substantial energy requirements for O3 generation and the inability to reuse the treated effluent directly. Lastly, a sensitivity analysis underscores the strong influence of chemical dosages in S1 and S2 on environmental and economic impacts, which is more significant than the impact of water reuse percentages in S4 and S5. The high electricity cost observed during 2022 negatively affects the energy-intensive scenarios (S3-S5), making coagulation-flocculation (S1-S2) even more convenient.

Electrooxidation using SnO2–RuO2–IrO2|Ti and IrO2–Ta2O5|Ti anodes as tertiary treatment of oil refinery effluent

AbstractIn the present work, treatability studies were carried out with oil refinery wastewater (effluent from the secondary treatment) using electrooxidation (EO) process employing two mixed oxide anodes: SnO2–RuO2–IrO2|Ti and IrO2–Ta2O5|Ti. Both electrodes' performance were compared by their capacity to generate active chlorine in a synthetic solution and organic matter mineralization of a sample with an average phenol (C6H6O) concentration of 100 mg L−1. Before degradation experiments, surface analysis, and linear sweep voltammetry tests were performed. SnO2–RuO2–IrO2|Ti anode yielded higher active chlorine, reaching an average concentration of 340 mg L−1 at 90 min of electrolysis and 25 mA cm−2. On the other hand, IrO2–Ta2O5|Ti anode only generated an average concentration of 200 mg L−1 at 90 min and 40 mA cm−2. Regarding the degradation experiments, SnO2–RuO2–IrO2|Ti anode showed the highest dissolved organic carbon removal, ranging from 26% to 40%. In addition, through a three‐dimensional excitation–emission matrix fluorescence analysis, it was possible to elucidate the degradation of C6H6O and some possible polycyclic aromatic hydrocarbons present in the effluent. The results suggested that 65%–90% of the hydrocarbons and C6H6O present in the effluent were degraded with the SnO2–RuO2–IrO2|Ti anode applying 25 mA cm−2 within the first 30 min of electrolysis, reaching almost 99% degradation at 90 min. The EO process using SnO2–RuO2–IrO2|Ti can be an alternative for tertiary treatment of oil refinery wastewater for degradation and mineralization of the remaining organic matter of secondary effluents (biological processes) via active chlorine species.

The Use of Fly Ash and Bottom Ash to Reduce COD, TSS, and Color in Textile Industry Wastewater Effluent

The textile industry wastewater effluent contains some levels of COD, TSS, and color, it must be reprocessed as a tertiary treatment using the filtration method. The goal of this research was to examine the ability of fly ash and bottom ash as filtration media to reduce the pollutant / organic load of COD, TSS, and color in textile industry wastewater effluent. The slow sand filter method was used in this study, and the filter media was derived from coal combustion waste. The variation used in this study is a variation of filter media (fly ash and bottom ash), with fly ash diameters of 0.11 and 0.35 mm, bottom ash diameters of 0.85 - 1.50 mm, and media thickness of 1.50 - 2.00 mm (10 cm and 20 cm). The study’s findings demonstrated that using bottom ash and fly ash media in the filtration process with a slow sand filter system could maximize the efficiency of reducing COD, TSS, and color levels in textile industry wastewater effluent. In fly ash media, it can reduce COD, TSS, and Color by 90.58%, 81.87%, and 100%. Meanwhile, Bottom Ash filter media has an average COD, TSS, and Color reduction of 87.80%, 81.87%, and of 100%.

30-and 90-day readmissions in lumbar spine surgery. Differences in prevalence and causes

BackgroundThe morbidity associated with surgical treatment of lumbar degenerative conditions has attracted increasing interest due to the economic impact on society, especially postoperative readmission. Limited studies have assessed this risk in a prospective, single-center consecutive fashion. ObjectiveTo assess the incidence and causes of 30- and 90-day unplanned readmission and revision surgery following surgical treatment for lumbar degenerative spine conditions at a tertiary treatment center. Study designProspective, single-center cohort study. MethodsAll patients undergoing degenerative lumbar spine surgery in a 1-year period from February 1st, 2016, were prospectively included. Patient characteristics, surgical information and information regarding postoperative complications, including readmission (30- and 90-days) and revision surgery were recorded. Readmissions were classified according to whether they were due to the surgical intervention specifically, or a medical complication. ResultsA total of 1399 patients underwent surgery for various lumbar degenerative pathologies in the study period and all were included. Of these, 9.4% (n = 132) were readmitted within 30 days of surgery and in some cases, multiple readmissions occurred (up to 3). The total 90-day readmission rate was 17.6%. Of these, 15% were related to the surgical procedure.The predominant medical related causes were systemic infection (30-day: 14.4%, 90-day: 10.7%), neurological symptoms (30-day: 6.3%, 90-day: 5.0%) and cardiovascular events (30-day: 8.1%, 90-day: 12.9%).The surgical related causes for readmission were pain (30-day: 13.1%, 90-day: 2.9%), wound complications (30-day: 11.3%, 90-day: 5.0% and re-herniation (30-day: 13.1%, 90-day: 2.9%).Age was the only factor with significant influence on readmission. ConclusionThe incidence of medical conditions causing unplanned 30-day readmissions following surgery for lumbar degenerative conditions, is significantly higher compared to readmissions related specifically to the surgical procedure. Examples of medical treatment included antibiotics, analgesics, laxatives, anticoagulants and beta blockers. The difference is even more pronounced for the 90-day readmissions. The predominant medical causes were systemic infections, neurological and cardiovascular events. Predominant causes related to the surgery were pain, wound complications and re-herniations. Readmissions may be reduced by optimizing the medical treatment and the pain management before discharge of the patient.

Harnessing water fleas for water reclamation: A nature-based tertiary wastewater treatment technology

Urbanisation, population growth, and climate change have put unprecedented pressure on water resources, leading to a global water crisis and the need for water reuse. However, water reuse is unsafe unless persistent chemical pollutants are removed from reclaimed water. State-of-the-art technologies for the reduction of persistent chemical pollutants in wastewater typically impose high operational and energy costs and potentially generate toxic by-products (e.g., bromate from ozonation). Nature-base solutions are preferred to these technologies for their lower environmental impact. However, so far, bio-based tertiary wastewater treatments have been inefficient for industrial-scale applications. Moreover, they often demand significant financial investment and large infrastructure, undermining sustainability objectives. Here, we present a scalable, low-cost, low-carbon, and retrofittable nature-inspired solution to remove persistent chemical pollutants (pharmaceutical, pesticides and industrial chemicals). We showed Daphnia's removal efficiency of individual chemicals and chemicals from wastewater at laboratory scale ranging between 50 % for PFOS and 90 % for diclofenac. We validated the removal efficiency of diclofenac at prototype scale, showing sustained performance over four weeks in outdoor seminatural conditions. A techno-commercial analysis on the Daphnia-based technology suggested several technical, commercial and sustainability advantages over established and emerging treatments at comparable removal efficiency, benchmarked on available data on individual chemicals. Further testing of the technology is underway in open flow environments holding real wastewater. The technology has the potential to improve the quality of wastewater effluent, meeting requirements to produce water appropriate for reuse in irrigation, industrial application, and household use. By preventing persistent chemicals from entering waterways, this technology has the potential to maximise the shift to clean growth, enabling water reuse, reducing resource depletion and preventing environmental pollution.

First study of the effect of wastewater treatment on microbial biodiversity at three wastewater treatment plants in Agadir, Morocco, using 16S rRNA sequencing

Wastewater treatment is a crucial step in preserving public health and the environment. The quality of treated wastewater depends on the efficiency of the treatment system, which necessitates the evaluation of effluent quality. This is the first study to evaluate the efficiency of three treatment processes used to treat wastewater in Agadir, Morocco. Microbial biodiversity was characterized at the inlet and outlet of three treatment plants based on sequencing of seven hypervariable regions of the 16 S rRNA gene. Based on the relative abundance of bacterial biodiversity between the inflow and effluent of AOURIR and ANZA WWTPs, activated sludge emerges as the more efficacious treatment in comparison to lamellar decantation. These two treatments reduced the relative abundances and even eliminated several bacteria, including pathogenic bacteria. However, the primary M’ZAR treatment increased bacterial biodiversity from the influent to the effluent, which requires secondary and tertiary treatments to eliminate pathogenic bacteria and prevent environmental pollution. This study demonstrates the importance of assessing effluent quality to protect public health and the health of systems that receive effluents.

Real-time integration of microalgae-based bioremediation in conventional wastewater treatment plants: Current status and prospects

With rising water scarcity leading to a risk of affecting 1.69 to 2.37 billion people in urban residents, the treatment and reuse of wastewater have been identified as one of the main avenues to preserve global water resources. Thus, wastewater treatment plants with capacities ranging from 8000 to 200,000 tons/day have been implemented to treat wastewater and discharge effluent with improved quality parameters. Nonetheless, the generation of 160,000–210,000 tons/year of sludge and the requirement for advanced treatment to achieve non-detectable residues are significant concerns for highly effective wastewater treatment. In this context, microalgae with the potential of effective nutrient removal from wastewater streams have been exploited in wastewater treatment at primary, secondary and tertiary treatment stages. Microalgae-based bioremediation generates valuable biomass with metabolites, namely lipids, proteins, and carbohydrates, which could be utilized in the value-added production of biofuels, biofertilizers, etc. Moreover, microalgae integrated wastewater treatment systems would substantially remove residual pollutants, nutrients, and pathogens with high removal efficiencies. Hence, the integration of microalgae into the conventional wastewater treatment process enhances the process sustainability while contributing to the concept of a circular bioeconomy. Nevertheless, limited studies are available on the potential of integrating microalgae in the conventional wastewater treatment plants for real-world applications, although several reviews are available in the literature focusing the microalgae-based wastewater treatment in a general context. Thus, the current review aims to address this gap in the literature by comprehensively assessing the prospects of integrating phycoremediation as the secondary and tertiary/advanced wastewater treatment processes, while discussing the challenges and future perspectives in the research domain.

Water and dialysis fluid purity for contemporary hemodialysis.

The purity of water and dialysis fluids is of utmost importance in ensuring the safe and effective administration of hemodialysis treatment to patients with chronic kidney disease. It is crucial to enforce compliance with international standards for dialysis water and fluids, as this is mandatory in reducing chemical hazards, mitigating the adverse effects of bioincompatibility resulting from contaminated water and ultimately enhancing long-term patient outcomes. Within this comprehensive review, we highlight the presence of water contaminants and thoroughly assess the existing international standards for dialysis water and fluids, spanning from pure to ultrapure. Additionally, we delve into the fundamental components of water purification and present a comprehensive range of water treatment options, encompassing pre-treatment, primary treatment (reverse osmosis), and tertiary water treatment. Furthermore, we outline recommended monitoring and maintenance procedures, ensuring the consistent delivery of high-quality water and dialysis fluids at the point of care. WATER PURIFICATION AND MONITORING SUSTAINABILITY AND FUTURE CHALLENGES: Importantly, we raise concerns regarding the sustainability and conservation of water resources in hemodialysis treatment. It is imperative that these concerns be addressed in the future to avert the potential shortage of this essential resource. In conclusion, the contemporary landscape of hemodialysis conditions has engendered an urgent necessity for advanced water treatment systems and optimized delivery of dialysis fluids. This review serves as a comprehensive update on the latest technological advancements aimed at meeting these critical demands. Dialysis water and fluids must adhere to increasingly stringent purity constraints, encompassing both biochemical and microbiological perspectives.

Influence of oxygen vacancies, surface composition, and crystallite size on the photoelectrochemical oxidation activity of C,N-codoped TiO2 for cefadroxil abatement along with O3

This study aims the development of photoelectrodes to be incorporated in a photoelectrocatalytic ozonation (PECO) process for tertiary treatment of urban wastewaters, targeting the removal of contaminants of emerging concern (CEC). PECO tests were performed using urban wastewater after secondary treatment fortified with Cefadroxil (CFX, C16H17N3O5S), as target model CEC. Three Nitrogen and Carbon doped TiO2 (CN–TiO2) electrodes were synthesized by anodizing at 50, 70, and 90 V, and calcined. These materials were characterized by X-Ray diffraction and Rietveld refinement, Scanning Electron Microscopy, Diffuse Reflectance Spectroscopy, X-ray photoelectron spectroscopy, chronoamperometry, and electrochemical impedance spectroscopy, to correlate defects with photoactivity. All photoanodes considerably reduced their main bandgaps by the incorporation of C and N species, to enable absorption capacities in the UV region using a Xe lamp. The lowest oxygen vacancy content and largest crystallite size were found for CN–TiO2-70, favoring the reduction of bulk defects that could act as recombination of charge carriers. Therefore, oxygen vacancies affect more the TiO2 photoactivity compared to the crystallite size or the light absorption capacity, confirming that a lower content of vacancies in the material bulk and surface doping significantly influence the activity as detected by Rietveld refinement, DRS, and XPS. The electrochemical techniques confirm that the highest photocurrent was obtained for CN–TiO2-70, whence this photoanode was chosen to carry out the CFX degradation. A point defect model simulating Nyquist plot reveals that the photoactivity depends on the speed to diffuse oxygen vacancies through the TiO2 coating. All abatement processes were followed by high-performance liquid chromatography, and Total Organic Carbon (TOC). At neutral and alkaline conditions, CFX is eliminated to levels below the analytical detection limit after 90 min of treatment (TOC removals of 87 and 91%, respectively), indicating that the coupling between the CN–TiO2-70 photocatalyst and ozone is effective in eliminating the contaminant due to parallel routes forming •OH species. Lower CFX degradation observed at acidic pH (TOC removal of 70%) is assigned to the difficulty of oxidizing protonated CFX species.

Assessing the Efficacy of A Mo2C/Peroxydisulfate System for Tertiary Wastewater Treatment: A Study of Losartan Degradation, E. coli Inactivation, and Synergistic Effects

This work examines the use of pristine Mo2C as an intriguing sodium persulfate (SPS) activator for the degradation of the drug losartan (LOS). Using 500 mg/L Mo2C and 250 mg/L SPS, 500 μg/L LOS was degraded in less than 45 min. LOS decomposition was enhanced in acidic pH, while the apparent kinetic constant decreased with higher LOS concentrations. According to experiments conducted in the presence of scavengers of reactive species, sulfate radicals, hydroxyl radicals, and singlet oxygen participated in LOS oxidation, with the latter being the predominant reactive species. The presence of competitors such as bicarbonate and organic matter reduced the observed efficiency in actual matrices, while, interestingly, the addition of chloride accelerated the degradation rate. The catalyst showed remarkable stability, with complete LOS removal being retained after five sequential experiments. The system was examined for simultaneous LOS decomposition and elimination of Escherichia coli. The presence of E. coli retarded LOS destruction, resulting in only 30% removal after 3 h, while the system was capable of reducing E. coli concentration by 1.23 log. However, in the presence of simulated solar irradiation, E. coli was reduced by almost 4 log and LOS was completely degraded in 45 min, revealing a significant synergistic effect of the solar/Mo2C/SPS system.

Assessment of Prickly Pear Fruit Peel Mucilage in Form of Gel as a Green Coagulant for the Tertiary Treatment of Domestic Wastewater.

The application of natural coagulants derived from food byproducts in domestic wastewater tertiary treatment, which contains a number of impurities as suspended colloidal particles, has a potential use as essential substitutes for traditional inorganic coagulants. These biomaterials are a sustainable and environmentally friendly alternative that can be used to improve water quality and human health. In this study, prickly pear (PP) fruit peel mucilage gel was evaluated as a novel coagulant for the tertiary stage of domestic wastewater treatment. Jar tests were performed on residual raw water at the inlet (influent) and outlet (effluent) of the tertiary wastewater treatment (constructed wetland) with a coagulant dose of 12 mg L-1 at a pH of 13. The efficiency of green (i.e., mucilage) and inorganic chemical (i.e., FeCl3) coagulants was compared on the basis of turbidity and color removal. The flocs produced by the coagulants were characterized structurally by FTIR spectroscopy and Zeta potential analysis and morphologically by scanning electron microscopy (SEM). The results showed that the turbidity and the color removal efficiency of the mucilage compared to the FeCl3 at the outlet of the treatment (effluent) were practically the same, reaching 94% turbidity and 85-87% color removal efficiency with both coagulants. The structure and morphology of the flocs generated by the coagulants showed a higher content of organic matter trapped in the flocs. The floc formation observed mechanisms were adsorption/bridging for mucilage and charge neutralization for FeCl3. The results of this study demonstrated that the PP mucilage green coagulant can be used to enhance the quality of treatment of domestic wastewater in an eco-friendly and biodegradable manner.

Performance of a pilot-scale BDD reactor by numerical analysis of reaction rate parameters and additional numbers for mass transfers

The performance of a pilot-scale boron-doped diamond (BDD) reactor through a numerical analysis of reaction rate parameters and enhanced mass transfer has been investigated. The main objective of this research is to evaluate the efficiency of the reactor in mineralizing and degrading caffeine as an emerging contaminant. Based on the kinetic mechanisms and mass transport correlations reported in the literature, two reaction rate kinetic models for caffeine degradation are proposed and analyzed. The models consider different electrolytes (NaCl and Na2SO4) and applied current densities. The kinetic fitting process utilizes the gradient-maximal electrochemical approach, together with orthogonal placement methods, fourth-order Runge-Kutta (RK4) methods, and Nelder & Mead methods for optimization of kinetic parameters and spatial discretization of the material balance. Experimental data obtained from a factorial design with four factors and two levels (24) validate the proposed kinetic models. Caffeine degradation is achieved with NaCl and Na2SO4 electrolytes at concentrations of 60 ppm and 100 ppm, respectively. The corresponding applied loads are 1.5 AhL−1 and 3 AhL−1. Na2SO4 exhibits superior performance with a total organic carbon (TOC) removal efficiency of 99.13%, while NaCl achieves 31.47% mineralization. The behavior of caffeine degradation under the operational and scale conditions demonstrates that NaCl, as a support electrolyte, enables controlled charge transfer (current density) during the degradation process. In contrast, Na2SO4 as a support electrolyte introduces a mixed control of charge and mass transfer. The pilot-scale kinetic parameters obtained in this study provide valuable insights into the support electrolyte dynamics and current density dynamics in BDD-based Electrooxidation (EO) systems, particularly in complex matrix applications. Furthermore, the observed electrical consumption supports the potential application of EO as a viable technology for industrial-scale tertiary wastewater treatment, specifically for caffeine removal.

Are algae a promising ecofriendly approach to micro/nanoplastic remediation?

How to reduce microplastic pollution in aquatic ecosystem has become the focus of the global attention. The re-removal of microplastics of wastewater treatment plant (WWTP) effluent is gradually being put on the agenda. Recently, algae have been used as an ecofriendly remediation strategy for microplastic removal. Microplastics in sewage can be removed by algae through interception, capture, and entanglement, and can also form heterogeneous aggregates with algae, thereby reducing their free suspensions. Algae can recover nitrogen and carbon from wastewater and can be made into biochar, biofertilizers, and biofuels. However, problematically, this technology has been in the laboratory research stage, and existing research results cannot provide effective basis for its application. Microplastic removal via algae is influenced by wastewater flow rate, microplastic types, and pollutants. Microplastics are only physically fixed by algae, and ensuring that microplastics do not re-enter the environment during resource and capacity recovery is also a key factor limiting the implementation of this technology. The topic of this paper is to discuss the performance of the current tertiary wastewater treatment process - algae process to remove microplastics. Algae can remove nitrogen and phosphorus pollutants in sewage and remove microplastics at the same time, which can realize energy recovery and reduce ecological risks of the effluent. Although algae combined tertiary sewage treatment is a green technology for microplastic removal, its application still needs to be explored. The key challenges that need to be addressed, from single laboratory conditions to complex conditions, from small-scale testing to large-scale simulations, lie ahead of the application of this friendly technology.

Assessing Artificial Recharge on Groundwater Quantity Using Wells Recharge

In arid and semi-arid countries like Iraq, which suffer from water scarcity due to the effects of climate change and decreased surface water flow, groundwater is considered a vital source of irrigation water. This study is concerned with the influence of artificial recharge on the rehabilitation of the unconfined aquifer called Al-Dibdibba, located between the cities of Najaf and Kerbala in central Iraq around 31°550′ N and 32°450′ N and 43°300′ E and 44°300′ E. Due to excessive groundwater pumping rates for irrigation, this aquifer has suffered from groundwater decline and increased salinization during the previous 20 years. By establishing a conceptual model in the groundwater modeling system software (GMS), a numerical model was made to simulate groundwater flow. Artificial recharge using recycled water (tertiary treatment) from Kerbala's primary WWTP was carried out using 25 injection wells. The model was calibrated against historical and observed water level data for periods from 2016 to 2017. Three scenarios to predict how the aquifer would act with artificial recharge of 5%, 8%, and 10% from the total daily outflow of the WWTP in Kerbala (100000 m3/day) were studied. The calibration model met the observed values of groundwater levels with R2 = 0.989 for steady-state simulations and R2 = 0.987 for transient simulations. In the final analysis of the simulation, the results show that the maximum predicted groundwater level was raised by the injection of treated water through 25 wells by 1.05 m for 5000 m3/day, 2 m for 8000 m3/day, and 3 m for 10,000 m3/day recharge pumping rates. In addition, if water were pumped into the aquifer, it might support the development of agricultural lands covering more than 93 km2. So, artificial recharge can be considered one of the important solutions to adaptation to the effects of climate change and desertification in Iraq. Doi: 10.28991/CEJ-2023-09-09-010 Full Text: PDF

Biochar integrated reactive filtration of wastewater for P removal and recovery, micropollutant catalytic oxidation, and negative CO2 e: Process operation and mechanism.

Biochar (BC) use in water treatment is a promising approach that can simultaneously help address societal needs of clean water, food security, and climate change mitigation. However, novel BC water treatment technology approaches require operational testing in field pilot-scale scenarios to advance their technology readiness assessment. Therefore, the objective of this study is to evaluate the system performance of BC integrated into hydrous ferric oxide reactive filtration (Fe-BC-RF) with and without catalytic ozonation (CatOx) process in laboratory and field pilot-scale scenarios. For this investigation, Fe-BC-RF and Fe-CatOx-BC-RF pilot-scale trials were conducted on synthetic lake water variants and at three municipal water resource recovery facilities (WRRFs) at process flows of 0.05 and 0.6L/s, respectively. Three native and two iron-modified BCs were used in these studies. The commercially available reactive filtration process (Fe-RF without BC) had 96%-98% total phosphorus (TP) removal from 0.075- and 0.22-mg/L TP, as orthophosphate process influent in these trials. With BC integration, phosphorus removal yielded 94%-98% with the same process-influent conditions. In WRRF field pilot-scale studies, the Fe-CatOx-BC-RF process removed 84%-99% of influent total phosphorus concentrations that varied from 0.12 to 8.1 mg/L. Nutrient analysis on BC showed that the recovered BC used in the pilot-scale studies had an increase in TP from its native concentration, with the Fe-amended BC showing better P recovery at 110% than its unmodified state, which was 16%. Lastly, the field WRRF Fe-CatOx-BC-RF process studies showed successful destructive removals at >90% for more than 20 detected micropollutants, thus addressing a critical human health and environmental water quality concern. The research demonstrated that integration of BC into Fe-CatOx-RF for micropollutant removal, disinfection, and nutrient recovery is an encouraging tertiary water treatment technology that can address sustainable phosphorus recycling needs and the potential for carbon-negative operation. PRACTITIONER POINTS: A pilot-scale hydrous ferric oxide reactive sand filtration process integrating biochar injection typically yields >90% total phosphorus removal to ultralow levels. Biochar, modified with iron, recovers phosphorus from wastewater, creating a P/N nutrient upcycled soil amendment. Addition of ozone to the process stream enables biochar-iron-ozone catalytic oxidation demonstrating typically excellent (>90%) micropollutant destructive removals for the compounds tested. A companion paper to this work explores life cycle assessment (LCA) and techno-economic analysis (TEA) to explore biochar water treatment integrated reactive filtration impacts, costs, and readiness. Biochar use can aid in long-term carbon sequestration by reducing the carbon footprint of advanced water treatment in a dose-dependent manner, including enabling an overall carbon-negative process.

A Retrospective Cohort Study to Assess the Long-term Retention and Outcome among Inpatients Admitted to a Tertiary Care Addiction Psychiatry Unit in India

Background and Aims: Understanding the long-term outcomes of patients with substance use disorders can help to understand their course and prognosis. We aimed to find out the 10-year retention of patients who underwent short-term inpatient treatment at a tertiary care addiction psychiatry treatment facility. Methodology: This retrospective cohort study evaluated the medical records of patients who underwent short-term inpatient treatment in the year 2009 in an addiction treatment facility. The last year retention in treatment was ascertained at 1, 2, 5, and 10 years using case records. Attempt was made to contact the patients to assess their current status using telephonic interview. Results: Of the 572 patients included in the study, 40.9%, 24.7%, 10.5%, and 5.1% of the initial sample were retained at 1, 2, 5, and 10 years, respectively. Only 3.0% of the sample were retained in treatment continuously without dropping out even once. Several factors such as having a comorbid medical disorder, previous inpatient setting treatment, or routine planned discharge were associated with better retention in treatment at some time points. Of the 58 patients who could be contacted telephonically to assess the 10-year outcomes, a significant proportion (41.4%) was abstinent from all substances except tobacco. Among these patients who could be followed up (about 10% of the initial sample), the most common reason of not being in treatment was that they were abstinent from substances. Conclusion: Gradual attrition from treatment occurs over long-term time course among patients admitted with substance use disorders, though many re-enter treatment process.

Nutrient uptake in tropical rivers receiving wastewater treatment plant discharge: High mass removal but low nutrient uptake efficiencies

Wastewater treatment plants (WWTPs) have eliminated many problems related to sewage inputs to aquatic systems. However, the treated effluents still affect river and stream ecosystems. Yet, very limited information is available about the fate of treated effluents in tropical receiving water bodies. Here, we examined the longitudinal changes in ammonium (NH4-N), nitrate (NO3-N), and soluble reactive phosphorus (SRP) concentrations in reaches downstream from chronic WWTP inputs in three receiving rivers in São Paulo state (Southeastern Brazil). The studied WWTPs were not designed or operated to have specific tertiary treatment for nutrient removal at the time of the study. We conducted a total of five sampling campaigns between 2019 and 2021. We applied the nutrient spiraling approach to these high-magnitude nutrient additions to examine net nutrient uptake. Changes in nutrient loads along the reaches were also examined. Overall, nutrient concentrations and loads were considerably increased by WWTP discharges. Net uptake lengths (SW-net) for NO3-N, NH4-N, and SRP ranged from 1.2 to 13.6, 1.5–infinity (uptake coefficient < 0), and 1.2–7.5 km, respectively. Net uptake velocities (Vf-net) varied between 0.7–2.5, −0.4 to 4.1, and 0.2–10.2 mm/min, respectively. Areal net uptake rates (Unet) ranged from 0.78 to 10.7, −20.08–45.8, and 0.18–4.4 g/m2/min for NO3-N, NH4-N, and SRP, respectively. High export (long SW-net) and limited net uptake along the reaches (low Vf-net) indicated that nutrients were transported downstream for long distances without efficient removal (nutrient availability higher than demand) despite the high mass removal (high Unet). These results suggest that the export of nutrients is substantial, potentially creating water quality impairments to downstream ecosystems. Our study highlighted that WWTPs with limited nutrient removal have considerable effects on water chemistry, nutrient cycling and loading in tropical receiving freshwaters.

A mathematical model for ammonium removal and recovery from real municipal wastewater using a natural zeolite

A study was carried out to remove/recover ammonium (NH4+) from residual effluents in tertiary treatment by sorption/desorption processes onto a natural clinoptilolite zeolite (NZ) in batch and fixed-bed column systems. Batch equilibrium and kinetic experiments were performed at different loading of NZ and contact time intervals, respectively. The results obtained in batch were fitted by the Freundlich and Langmuir isotherms and mass action law model. The Freundlich isotherm showed better agreement with experimental data than the Langmuir model. The isotherm studies revealed a type III with a maximum capacity of 2.8 ± 0.2 mg/g at 40 mgNH4+/L. Moreover, the data from the fixed-bed column studies was well fitted by a mass transfer model, considering the intraparticle diffusion resistance given by the linear driving force model (LDF). Finally, the capacity of NH4+ recovery of activated zeolite was measured experimentally and by a robust dynamic desorption model. The column desorption results demonstrated that higher recoveries (92–99.99%) were observed when increasing the flow rate to 0.12 mL/min. The uniqueness of this study is its capability to simulate both the sorption and desorption processes of the naturally derived sorbent for the effective removal and recovery of NH4+-N from real wastewater stream.

Comparison of antibiotic-resistant Escherichia coli and extra-intestinal pathogenic E. coli from main river basins under different levels of the sewer system development

Antimicrobial-resistant Escherichia coli in the aquatic environments is considered a strong indicator of sewage or animal waste contamination and antibiotic pollution. Sewer construction and wastewater treatment plant (WWTP) infrastructure may serve as concentrated point sources of contamination of antibiotic-resistant bacteria and antibiotic resistance genes. In this study, we focused on the distribution of antimicrobial-resistant E. coli in two rivers with large drainage areas and different urbanisation levels. E. coli from Kaoping River with drainage mainly from livestock farming had higher resistance to antibiotics (e.g. penicillins, tetracyclines, phenicols, aminoglycosides, and sulpha drugs) and presented more positive detection of antibiotic-resistance genes (e.g. ampC, blaTEM, tetA, and cmlA1) than that from Tamsui River. In Kaoping River with a lower percentage of sewer construction nearby (0–30%) in contrast to a higher percentage of sewer construction (55–92%) in Tamsui River, antimicrobial-resistant E. coli distribution was related to livestock farming waste. In Tamsui River, antimicrobial resistant E. coli isolates were found more frequently in the downstream drainage area of WWTPs with secondary water treatment than that of WWTPs with tertiary water treatment. The Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR showed that the fingerprinting group was significantly related to the sampling site (p < 0.01) and sampling date (p < 0.05). By utilising ERIC-PCR in conjunction with antibiotic susceptibility and antibiotic-resistance gene detection, the relationship among different strains of E. coli could be elucidated. Furthermore, we identified the presence of six extra-intestinal pathogenic E. coli isolates and antibiotic-resistant E. coli isolates near drinking water sources, posing a potential risk to public health through community transmission. In conclusion, this study identified environmental factors related to antibiotic-resistant bacteria and antibiotic-resistance gene contamination in rivers during urban development. The results facilitate the understanding of specific management of different waste streams across different urban areas. Periodic surveillance of the effects of WWTPs and livestock waste containing antibiotic-resistant bacteria and antibiotic-resistance genes on river contamination is necessary.