Effluent Concentrations Research Articles

Microbial nutrient recovery cell as an efficient and sustainable nutrient recovery option in sewage treatment

Globally, nutrient pollution is a serious and challenging concern. Wastewater treatment plants (WWTPs) are designed to prevent the discharge of contaminants resulting from anthropogenic sources to the receiving water bodies. In this study, seasonal nutrient pollution load, and biological nutrient removal efficiency of an anoxic aerobic unit based WWTP were investigated. Seasonal assessment revealed that the average total nitrogen removal efficiency and total phosphorus removal efficiency of the WWTP do not meet the discharge standard of 10 mg/L and 1 mg/L, respectively. Furthermore, the WWTP does not utilize the energy contained in the wastewater. In this regard, dual chamber MFC (D-MFC) has emerged as a promising solution that can not only treat wastewater but can also convert chemical energy present in the wastewater into electrical energy. However, higher N O3− (57 ± 4 mg/L) and P–P O43− (6 ± 0.52 mg/L) concentration in cathodic effluent is a major drawback in D-MFC. Therefore, to solve this issue, D-MFC was transformed into a microbial nutrient recovery cell (MNRC) which demonstrated a final N H4+-N and P–P O43− concentration of nearly 1 mg/L with N H4+-N and P–P O43− recovery up to 74 % and 69 %, respectively in the recovery chamber. Besides, MNRC attained a maximum power density of 307 mW/m3 and a current density of 1614 mA/m3, thus indicating MNRC is an eco-friendly, energy-neutral, and promising technology for electricity generation and recovering nutrients.

Impact of a WWTP effluent overland flow on the properties of a mediterranean riparian soil

In this work we aim to assess the impact of a WWTP effluent overland flow on properties and nutrient concentrations of a riparian soil, in order to explore the potential of this practice as a nature-based treatment. We set two study zones of 150 m2 on the field, one control and one that received the WWTP effluent on its surface for one month. Samples were taken before and after the effluent overland flow system, to test the impact of the effluent on soil properties through a BACI design, and after 17 months, to evaluate the recovery of the soil. Two depths were studied: 0–5 cm and 5–20 cm. The effluent overland flow triggered an increase in exchangeable sodium percentage and a decrease in nitrate concentration in both depths, and an increase in ammonium concentration in 0–5 cm depth. After 17 months, there were not found relevant differences among zones. In conclusion, this practice could be used in the purpose to reduce the nutrient concentrations of WWTP effluents. This practice could be relevant for regions where WWTP effluents are discharged in low-flow or intermittent streams, such as semi-arid regions or the Mediterranean region.

Optimization of ethylene thiourea, cyanide, and heavy metals removal and gas production enhancement in organosulfur pesticide wastewater using ferromagnetic biochar in anaerobic membrane bioreactor

Anaerobic membrane bioreactor (AnMBR) and biochar technologies have rarely been used in pesticide wastewater treatment, their performance and feasibility need further confirmation. This study compared a novel AnMBR (R2) with ferromagnetic biochar derived from traditional Chinese medicine residues to a conventional AnMBR (R1) without ferromagnetic biochar, focusing on degradation of organosulfur pesticide wastewater characterized by high toxicity and COD content and observing biogas production under various temperatures and hydraulic retention times (HRTs). The relationship between wastewater toxicity (COD, ethylene thiourea (ETU), cyanide, total manganese (TMn) and total zinc (TZn)) and biogas production was also explored. The optimal parameters were determined, with R1 and R2 having the same effect. Compared to R1, ETU removal in R2 increased from 40.7 % to 61.0 % (10 °C), from 64.6 % to 71.6 % (15 °C), from 76.9 % to 87.0 % (25 °C), and from 86.4 % to 92.4 % (35 °C). Similarly, the HRT was 48 h at 15 °C in R2 and at 25 °C in R1, both achieving a comparable COD removal of approximately 75.2 %. Cyanide removal in R2 was 2.4–9.6 % higher than in R1 across various temperatures. In addition, compared to R1, effluent concentrations of TMn in R2 were reduced by 378.8 ± 96.2 mg/L at 25 °C with the HRT of 18 h. The TZn average enhancements removal in R2 were higher than those in R1 by 6.6 % (10 °C), 10.0 % (15 °C), 3.8 % (25 °C), and 4.1 % (35 °C). Importantly, biogas production in R2 increased by 5.3–15.9 % at 25 °C. There was a significant negative correlation between biogas production and the concentrations of ETU and cyanide. This highlighted the dual benefit of R2 in enhancing pollutant degradation and biogas energy recovery, providing basic data for energy-efficient and low-carbon operations in pesticide wastewater treatment.

Potential effects of Cu2+ stress on nitrogen removal performance, microbial characteristics, and metabolism pathways of biofilm reactor

Sequencing batch biofilm reactors (SBBR) were utilized to investigate the impact of Cu2+ on nitrogen (N) removal and microbial characteristics. The result indicated that the low concentration of Cu2+ (0.5 mg L−1) facilitated the removal of ammonia nitrogen (NH4+-N), total nitrogen (TN), nitrate nitrogen (NO3−-N), and chemical oxygen demand (COD). In comparison to the average effluent concentration of the control group, the average effluent concentrations of NH4+-N, NO3−-N, COD, and TN were found to decrease by 40.53%, 17.02%, 10.73%, and 15.86%, respectively. Conversely, the high concentration of Cu2+ (5 mg L−1) resulted in an increase of 94.27%, 55.47%, 22.22%, and 14.23% in the aforementioned parameters, compared to the control group. Low concentrations of Cu2+ increased the abundance of nitrifying bacteria (Rhodanobacter, unclassified-o-Sacharimonadales), denitrifying bacteria (Thermomonas, Comamonas), denitrification-associated genes (hao, nosZ, norC, nffA, nirB, nick, and nifD), and heavy-metal-resistant genes related to Cu2+ (pcoB, cutM, cutC, pcoA, copZ) to promote nitrification and denitrification. Conversely, high concentration Cu2+ hindered the interspecies relationship among denitrifying bacteria genera, nitrifying bacteria genera, and other genera, reducing denitrification and nitrification efficiency. Cu2+ involved in the N and tricarboxylic acid (TCA) cycles, as evidenced by changes in the abundance of key enzymes, such as (EC:1.7.99.1), (EC:1.7.2.4), and (EC:1.1.1.42), which initially increased and then decreased with varying concentrations of Cu2+. Conversely, the abundance of EC1.7.2.1, associated with the accumulation of nitrite nitrogen (NO2−-N), gradually declined. These findings provided insights into the impact of Cu2+ on biological N removal.

Pilot-scale evaluation of cascade anaerobic digestion of mixed municipal wastewater treatment sludges.

This work assessed the performance of a pilot-scale cascade anaerobic digestion (AD) system when treating mixed municipal wastewater treatment sludges. The cascade system was compared with a conventional continuous stirred tank reactor (CSTR) digester (control) in terms of process performance, stability, and digestate quality. The results showed that the cascade system achieved higher volatile solids removal (VSR) efficiencies (28-48%) than that of the reference (25-41%) when operated at the same solids residence time (SRT) in the range of 11-15 days. When the SRT of the cascade system was reduced to 8days the VSR (32-36%) was only slightly less than that of the reference digester that was operated at a 15-day SRT (39-43%). Specific hydrolysis rates in the first stage of the cascade system were 66-152% higher than those of the reference. Additionally, the cascade system exhibited relatively stable effluent concentrations of volatile fatty acids (VFAs: 100-120 mg/l), while the corresponding concentrations in the control effluent demonstrated greater fluctuations (100-160 mg/l). The cascade system's effluent pH and VFA/alkalinity ratios were consistently maintained within the optimal range. During a dynamic test when the feed total solids concentration was doubled, total VFA concentrations (85-120 mg/l) in the cascade system were noticeably less than those (100-170 mg/l) of the control, while the pH and VFA/alkalinity levels remained in a stable range. The cascade system achieved higher total solids (TS) content in the dewatered digestate (19.4-26.8%) than the control (17.4-22.1%), and E. coli log reductions (2.0-4.1 log MPN/g TS) were considerably higher (p < 0.05) than those in the control (1.3-2.9 log MPN/g TS). Overall, operating multiple CSTRs in cascade mode at typical SRTs and mixed sludge ratios enhanced the performance, stability digesters, and digestate quality of AD. PRACTITIONER POINTS: Enhanced digestion of mixed sludge digestion with cascade system. Increased hydrolysis rates in the cascade system compared to a reference CSTR. More stable conditions for methanogen growth at both steady and dynamic states. Improved dewaterability and E. coli reduction of digestate from the cascade system.

Anomalies of solute transport in flow of shear-thinning fluids in heterogeneous porous media

Solute transport and mixing in heterogeneous porous media are important to many processes of practical applications. Most of the previous studies focused on solute transport in flow of Newtonian fluids, whereas there are many processes in which the phenomenon takes place in flow of a non-Newtonian fluid. In this paper, we develop a computational approach to evaluate and upscale dispersion of a solute in flow of a shear-thinning (ST) fluid in a heterogeneous porous medium. Our results indicate that the dispersivity is a non-monotonic function of the Péclet number and the shear rate, and this behavior is accentuated by the heterogeneity of the pore space and spatial correlations between the local permeabilities. As a result, solute transport in ST fluids deviates significantly from the same phenomenon in Newtonian fluids. Moreover, the shear-dependence of the dispersivity strongly influences the fate of solute transport in porous media at large length scales, including larger effluent concentration at the breakthrough point, which also occurs much faster than Newtonian fluids. To provide further evidence for the numerical findings, we compare dispersion in flow of a power-law fluid in a single tube with the same in a bundle of such tubes. Our results emphasize the shortcomings of the current theories of dispersion to account for the role of fluid rheology in solute mixing and spreading.

Fate of organic nitrogen in amino acids during alternating denitrification and nitrification

Nitrogen-containing organic compounds, such as amino acids in soybean-processing wastewater, can be used as electron donors to drive denitrification, but their biodegradation releases ammonium nitrogen that must be nitrified and denitrified to maintain total-nitrogen removal. We evaluated glutamate, isoleucine, and methionine as example amino acids to explore the fate of nitrogen when they are used as electron donor to drive denitrification during two stages of alternating denitrification and nitrification. The experimental results documented that each amino acid enabled complete removal of exogenous NO3− in the first stage of denitrification and complete NO3− removal in the second stage. After two alternations of denitrification and nitrification, the TN concentration in effluent was less than 5 mgN/L for all amino acids, and COD in the effluent was less than 25 mg/L. Based on stoichiometry and the ratio of chemical oxygen demand (COD) to organic N in each amino acid, 57%–66% of the COD from the amino acids had to be oxidized to reduce the endogenous NO3−–N in the first stage. N from the amino acids was nitrified and denitrified in the subsequent nitrification and denitrification stages, and the percentages of COD used for denitrification from both stages were 72%–85%. The residual NH4+-N concentrations were slightly higher with methionine, possibly due to inhibition from sulfide released from methionine.

Utilizing Microbial Fuel Cells For Simultaneous Treatment Of Solid Waste Water And Energy Generation

The proposed biocatalyst utilized in the microbial fuel cell (MFC) experiment demonstrated exo-electrogenic activity, with species such as Mycobacterium and Shewanella (Pseudomonas) sourced from sewer wastewater. Chemical parameters from the initial experimental trial did not comply with Environmental Protection Agency (EPA) limits. The total suspended solids (TSS) in the second MFC trial were the only parameter to meet the EPA threshold of 50 ppm, with influent and effluent concentrations of 96 ppm and 23.1 ppm, respectively. Consequently, supplementary treatment methods are required to achieve EPA discharge standards. The second trial indicated that the MFC setup effectively reduced metal concentrations, including Cr, Mn, Pb, and Zn, to levels that satisfy EPA surface water effluent discharge criteria. Keywords: microbial fuel cell, anode chamber, cathode chamber, wastewater, energy generation. Aims Research Journal Reference Format: Adeniyi O. A., Bakri A.J., Samuel O. Fadipe, Shakirat B. A., Adebayo O.C. &amp; Oyetunde R.A. (2024): Utilizing Microbial Fuel Cells For Simultaneous Treatment Of Solid Waste Water And Energy Generationelta. Advances in Multidisciplinary and Scientific Research Journal Vol. 10. No. 2. Pp 55-69. www.isteams.net/aimsjournal. dx.doi.org/10.22624/AIMS/V10N2P6

Continuous CO2 capture and reduction to CO by circulating transition-metal-free dual-function material in fluidized-bed reactors

To mitigate global warming and achieve a sustainable society, innovative technologies for efficient CO2 utilization are required. Integrated CO2 capture and reduction (CCR) using dual-function materials (DFMs) is favorable owing to its potentially low energy consumption, capital investment, and processing costs. Although numerous studies have focused on catalytic science, continuous and steady-state CCR operations have not been sufficiently addressed from an engineering perspective. In this study, a circulating fluidized bed (CFB) system is investigated for continuous CCR to syngas (CO + H2). In the CFB system, transition-metal-free DFM (Na/Al2O3) particles are circulated between two bubbling fluidized-bed reactors. The DFM captures CO2 in one reactor (CO2 capture reactor) and reduces the captured CO2 to CO by the reaction with H2 in the other reactor (H2 reactor). The effluent gas concentrations from both reactors reach steady state and are maintained for over 8 h. For the product gas from the H2 reactor, the CO2 conversion and CO selectivity exceed 80 % and 99 %, respectively. However, the H2 conversion is <20 %, indicating a potential challenge for the CFB system for integrated CCR. Furthermore, this study confirms that the H2/CO ratio for syngas can be controlled by adjusting the experimental conditions (particularly, the H2 flow rate). Consequently, the CFB system can be modified to facilitate the interaction between H2 gas and the DFM particles.

Does stricter sewage treatment targets policy exacerbate the contradiction between effluent water quality improvement and carbon emissions mitigation? An evidence from China

Rapid expansion and upgrading of wastewater treatment facilities globally, driven by stricter wastewater policies, significantly contribute to carbon emissions. China has contributed 30 % of carbon emissions in the world, 1 % of which comes from wastewater treatment, necessitating more understanding of the impact of policies, especially the stringent “10-Point Water Plan” policy. From a micro perspective, this study uses the difference-in-differences method to analyze the impact of wastewater treatment policies on water and carbon issues in China’s 2894 wastewater treatment plants (WWTPs), and delves into the heterogeneity, and mechanisms across various dimensions. The results show that stricter sewage treatment policy decrease effluent concentration of the chemical oxygen demand (COD) by 2.35 %, and also cause a 1.74 % rise in carbon emissions per 10,000 m3 of wastewater treated, intensifying the short-term contradiction, while the contradictions may fall in the long term. It is more significant in southern regions and the cities with lower environmental regulation intensity. Also, there are significant differences in different wastewater treatment technology and scale. Significant improvements in effluent water quality are observed in WWTPs with 100,000 to 200,000 m3/day capacity and those using biofilm treatment technology. Through mechanism analysis, reasonable expansion of urban pipelines and WWTPs, promotion of biofilm treatment technology, reduction of energy consumption, and improvement of pollutant reduction efficiency are feasible paths to improve water quality and reduce carbon emissions. This research provides a perspective on solving water-carbon contradictions in WWTPs, holding critical significance for urban wastewater treatment and carbon emission management.

Evaluation of the effluent concentrations of Karbala wastewater treatment plant using reliability analysis

Abstract The effective and consistent operation of wastewater treatment plant systems (WWTPs) is crucial for the sustainability of the environment and public health protection. The main objective of the present study is concentrated on assessing the reliability of the Karbala wastewater treatment plant’s (WWTP’s) performance. It investigates the plant’s efficiency through the weekly concentration values of three key water quality indicators, which are biochemical oxygen demand (BOD), total suspended solids (TSS), and chemical oxygen demand (COD) collected over 4 years of operation from 2020 to 2023. The methods employed were the coefficient of reliability (COR) method for plant performance in removing the effluent concentrations of 5-day biochemical oxygen demand, COD, and TSS. The analysis found that the COR values were generally close to 1 for all years, with the lowest value recorded at 0.71 in 2020, during the initial stabilization phase of the WWTP. The main finding was that the Karbala WWTP has been effective in pollutant removal. The present study is important because it supplies dependable data that wastewater treatment operators can use to assess their daily operations and gauge the success of biological treatment methods. It is worth noting that no study has been done on the reliability model for examining the quality of wastewater of the Karbala WWTP, and such a method of analysis is considered a new improvement for the evaluation of the plant to meet the Iraqi standards.

Occurrence of emerging contaminants in three river basins impacted by wastewater treatment plant effluents: Spatio-seasonal patterns and environmental risk assessment

The concern on the fate and distribution of contaminants of emerging concern (CECs) is a burning topic due to their widespread occurrence and potential harmful effects. Particularly, antibiotics have received great attention due to their implications in antimicrobial resistance occurrence. The impact of wastewater treatment plants (WWTP) is remarkable, being one of the main pathways for the introduction of CECs into aquatic systems. The combination of novel analytical methodologies and risk assessment strategies is a promising tool to find out environmentally relevant compounds posing major concerns in freshwater ecosystems impacted by those wastewater effluents. Within this context, a multi-target approach was applied in three Spanish river basins affected by different WWTP treated effluents for spatio-temporal monitoring of their chemical status. Solid phase extraction followed by ultra-high-performance liquid chromatography were used for the quantification of a large panel of compounds (n = 270), including pharmaceuticals and other consumer products, pesticides and industrial chemicals. To this end, water samples were collected in four sampling campaigns at three locations in each basin: (i) upstream from the WWTPs; (ii) WWTP effluent discharge points (effluent outfall); and (iii) downstream from the WWTPs (500 m downriver from the effluent outfall). Likewise, 24-h composite effluent samples from each of the WWTPs were provided in all sampling periods. First the occurrence and distribution of these compounds were assessed. Diverse seasonal trends were observed depending on the group of emerging compounds, though COVID-19 outbreak affected variations of certain pharmaceuticals. Detection frequencies and concentrations in effluents generally exceeded those in river samples and concentrations measured upstream WWTPs were generally low or non-quantifiable. Finally, risks associated with maximum contamination levels were evaluated using two different approaches to account for antibiotic resistance selection as well. From all studied compounds, 89 evidenced environmental risk on at least one occasion in this study.

Model-Based Analysis of Arsenic Retention by Stimulated Iron Mineral Transformation under Coastal Aquifer Conditions.

A multitude of geochemical processes control the aqueous concentration and transport properties of trace metal contaminants such as arsenic (As) in groundwater environments. Effective As remediation, especially under reducing conditions, has remained a significant challenge. Fe(II) nitrate treatments are a promising option for As immobilization but require optimization to be most effective. Here, we develop a process-based numerical modeling framework to provide an in-depth understanding of the geochemical mechanisms controlling the response of As-contaminated sediments to Fe(II) nitrate treatment. The analyzed data sets included time series from two batch experiments (control vs treatment) and effluent concentrations from a flow-through column experiment. The reaction network incorporates a mixture of homogeneous and heterogeneous reactions affecting Fe redox chemistry. Modeling revealed that the precipitation of the Fe treatment caused a rapid pH decline, which then triggered multiple heterogeneous buffering processes. The model quantifies key processes for effective remediation, including the transfer of aqueous As to adsorbed As and the transformation of Fe minerals, which act as sorption hosts, from amorphous to more stable phases. The developed model provides the basis for predictions of the remedial benefits of Fe(II) nitrate treatments under varying geochemical and hydrogeological conditions, particularly in high-As coastal environments.

The impact of printing industry effluent on the growth and antioxidant response of the freshwater green microalga Chlorella sorokiniana

Contamination of aquatic ecosystems with printing industry wastewater is a serious concern because of the toxicity associated with the effluent components and a tendency to create cascading ecological effects. The influence of printing-press effluent on the freshwater microalga Chlorella sorokiniana strain UTEX2714 was studied under controlled laboratory conditions. The microalga was subjected to various effluent concentrations prepared by diluting printing-press effluent with bold basal medium (BBM) in the following ratios (effluent:medium): 1:149, 1:119, 1:99, 5:95 and 10:90, reflecting greater concentrations of the effluent. The control BBM had no effluent added. Higher effluent concentrations had a negative impact on the cell density of C. sorokiniana; at low effluent concentrations the algae displayed a high growth rate and high chlorophyll a production (p < 0.05), although total chlorophyll content did not differ significantly among treatments (p ≥ 0.05). This study also discovered an increase in peroxidase activity in this microalga in response to higher concentrations of printing-press effluent, which indicated an increase in oxidative stress that prompted antioxidant defence mechanisms. We conclude that printing-press effluent adversely affects the physiology of C. sorokiniana, indicating the potential of printing wastewater to harm phytoplankton in freshwater environments.

Pharmaceutical emissions on the example of the Baltic Sea catchment: comparing measurements with multi-tier predictive models

Currently, there is uncertainty about emissions of pharmaceuticals into larger closed ecosystems that are at risk such as the Baltic Sea. There is an increasing need for selecting the right strategies on advanced wastewater treatment. This study analysed 35 pharmaceuticals and iodinated X-ray contrast media in effluents from 82 Wastewater Treatment Plants (WWTPs) across Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland and Sweden. Measured concentrations from Finland and Denmark were compared to predicted effluent concentrations using different levels of refinement. The concentrations predicted by the Total Residue Approach, as proposed by the European Medicines Agency, correlated with R2 of 0.18 and 0.031 to measured ones for Denmark and Finland, respectively and the predicted data were significantly higher than the measured ones. These correlations improved substantially to R2 of 0.72 and 0.74 after adjusting for estimated human excretion rates and further to R2 = 0.91 and 0.78 with the inclusion of removal rates in WWTPs. Temporal analysis of compound variations in a closely monitored WWTP showed minimal fluctuation over days and weeks for most compounds but revealed weekly shifts in iodinated X-ray contrast media due to emergency-only operations at X-ray clinics during weekends and an abrupt seasonal change for gabapentin. The findings underscore the limitations of current predictive models and findings (...) demonstrate how these methodologies can be refined by incorporating human pharmaceutical excretion/metabolization as well as removal in wastewater treatment plants to more accurately forecast pharmaceutical levels in aquatic environments.

IMPACT OF DIFFERENT ORGANIC AND INORGANIC AMENDMENTS ON GROWTH AND YIELD OF MUNG BEAN IRRIGATED WITH TEXTILE EFFLUENTS

Water is an important substance for all life on earth, and it is essential for human beings, financial improvement, and the existence of ecological units. The quality and quantity of the water supply is very important, especially during irrigation. Due to the extensive measurement of water and colour associated with the manufacturing process, textile printing, and dyeing production lines around the world pose a major environmental risk. Textile wastewater contains a lot of pollutants including pH, temperature, shade, COD, BOD, TSS, TDS, EC, and heavy metals. This textile runoff continues to irrigate agricultural land, causing contamination of soils and plant systems with heavy metals. Therefore, adding organic and inorganic modifiers to soil is an effective technique for fixing heavy metals. Irrigate pots with textile wastewater of selected concentrations (10%, 25%, 50%, and 100%) collected in specific industrial sectors. The parameters of vegetative growth are reduced by increasing the concentration of textile effluent. Note the substantial reduction in the growth of plants applying wastewater at 100% concentration. In the case of T5, a significant increase in growth parameters was observed, where only tap water was used to pressurize the sludge, while dilute wastewater also enhanced growth at concentrations of 10% and 25%. For the chlorophyll content of mung bean plants, when the wastewater concentration is 100%, the recorded decrease is greater, followed by 10% and 25% respectively. The presence of heavy metals in wastewater reduces plant growth. In the experiment, all four treatments contained organic amendments (pressed sludge, poultry manure, biogas slurry, and farmyard manure). The other four treatment methods are pressure treatment of textile wastewater and the amount of organic modifier is 2%. By adding a correcting agent, the utilization rate of Cr is reduced, as the correcting agent will increase the pH of the soil, thus reducing the solubility of the metal. In addition, Cr can form insoluble complexes with organic materials, thus reducing its solubility.

Green solutions for antibiotic pollution: Assessing the phytoremediation potential of aquatic macrophytes in wastewater treatment plants

We compared the ability of one emergent (Sagittaria montevidensis), two floating (Salvinia minima and Lemna gibba), and one heterophyllous species (Myriophyllum aquaticum) to simultaneously remove sulfamethoxazole, sulfadiazine, ciprofloxacin, enrofloxacin, norfloxacin, levofloxacin, oxytetracycline, tetracycline, doxycycline, azithromycin, amoxicillin, and meropenem from wastewater in a mesocosm-scale constructed wetland over 28 days. Antibiotic concentrations in plants and effluent were analyzed using an LC-MS/MS to assess the removal rates and phytoremediation capacities. M. aquaticum did not effectively mitigate contamination due to poor tolerance and survival in effluent conditions. S. minima and L. gibba demonstrated superior efficiency, reducing the antibiotic concentrations to undetectable levels within 14 days, while S. montevidensis achieved this result by day 28. Floating macrophytes emerge as the preferable choice for remediation of antibiotics compared to emergent and heterophyllous species. Antibiotics were detected in plant tissues at concentrations ranging from 0.32 to 29.32 ng g−1 fresh weight, highlighting macrophytes' ability to uptake and accumulate these contaminants. Conversely, non-planted systems exhibited a maximum removal rate of 65%, underscoring the persistence of these molecules in natural environments, even after the entire experimental period. Additionally, macrophytes improved effluent quality regardless of species by reducing total soluble solids and phosphate concentrations and mitigating ecotoxicological effects. This study underscores the potential of using macrophytes in wastewater treatment plants to enhance overall efficiency and prevent environmental contamination by antibiotics, thereby mitigating the harmful impact on biota and antibiotic resistance. Selecting appropriate plant species is crucial for successful phytoremediation in constructed wetlands, and actual implementation is essential to validate their effectiveness and practical applicability.

Model based control of dissolved oxygen in paper mill effluent using response surface methodology

In this work, for analysis, one and half liters of (effluent) waste water from paper mill industry was used in batch reactor, to study the variations in DO values under three operating conditions are speed, concentration of effluent in water and time with respect to step change in oxygen feed. The experiment was done 270 trails under specified operating conditions. Experimental data were collected, many trials were done using response surface method (RSM) and respective optimum values of three operating parameters were obtained for DO value ranging from 5 to 6 ppm. In trials, RSM predicted 82.732 % effluent to water concentration, stirrer speed at 150 rpm and at 0.091 min predicted DO is 5.7 ppm, from obtained experimental results shown in figure 3 for 80 % and 90 % concentration. RSM predicted optimal conditions are considered for experimental study and three control strategies such as particle swarm optimization (PSO) based PID control and state feedback controller with Integral action and state observer were used to achieve desired DO value. A comparative study was done among three controllers and it was concluded that state feedback controller with Integral action based control strategy yield better closed loop results in-terms of time-domain and stability analysis.

Environmental Impact of Petroleum Refinery Effluent on Groundwater Pollution: A Case Study of Maysan Refinery, Iraq

The study aimed to investigate the environmental impact of the refinery's wastewater on groundwater within the refinery and the surrounding area. Six different testing sites were chosen to measure the concentrations of groundwater pollutants according to their distance from the untreated oil effluent discharge lagoon. The study period lasted for six months, as the testing work began in April and ended in September 2023. The results showed a clear effect of untreated petroleum effluent on the properties of groundwater, as the concentrations of petroleum effluent (oil and grease, TOC, phenol) and heavy metals (Ni, Cd, Pb) exceeded the permissible limits, as well as related parameters (TDS, EC, Cl, SO4) according to WHO specifications. As for the concentrations of the parameters (BOD, COD), there was no clear effect of the effluent on them, and on the contrary, their values began to increase at the testing sites far from the refinery. The groundwater was greatly affected by a distance of 5 km from the effluent collection lagoon (testing sites:GW1, GW2, GW3, and GW4), and it was not suitable for human use until after it was treated. As for the remaining of the distance (testing sites:GW5, GW6) to the nearest residential area (from 5 km to 9 km), the groundwater was limited to use for irrigation according to WQI guidelines. The study recommends that, in order to reduce pollution of refinery effluent, the responsible administration should use regular wastewater networks, construct a treatment plant for this effluent, and discharge the treated effluent to the nearest water source

A static and dynamic analysis of nonionic-based binary surfactant systems for adsorption mitigation in a carbonate reservoir with high salinity

Surfactants are crucial in chemical enhanced oil recovery, but high adsorption onto rocks reduces their efficiency and economic viability. Sacrificial agents, such as alkalis, nanoparticles, and polymers have been investigated to mitigate this issue but they in turn present drawbacks such as poor oil interaction, compatibility issues, pore plugging, and increased costs. Binary surfactant systems, due to their favorable potential synergistic interactions, are proposed as solutions for reducing surfactant adsorption. Static adsorption experiments were conducted to assess the effect of the binary surfactants on adsorption efficiency, and the impact of salinity on the adsorption process equilibrium was also studied. Five core flooding experiments under reservoir temperature (41∘C), reservoir pressure (21 MPa), and high salinity (23.4 wt.%) were conducted to evaluate dynamic adsorption. The surfactant concentrations in supernatant and effluent, after the adsorption process were determined via interfacial tension tests using a spinning drop method. The results showed a significant reduction in surfactant adsorption on carbonate rocks, from 9.99 mg/g-rock to 0.68 mg/g-rock for anionic surfactants and from 5.38 mg/g-rock to 0.19 mg/g-rock for zwitterionic surfactants, with corresponding dynamic reductions of 61% and 89%. Our results were further evidenced by the little to no changes in the differential pH curves in the adsorption process of the binary surfactant systems. This study presents a cost-effective approach for significantly reducing surfactant adsorption on carbonate rocks and aids in designing surfactant formulations for adsorption reduction in high-temperature, high-salinity carbonate reservoirs.