Conventional Treatment Systems Research Articles

Photo-Fenton oxidation of Orange G azo dye: process optimization and mineralization mechanism

Textile effluents containing synthetic dyes are one of the most important sources of water pollution. Several dyes are toxic to the aquatic life and indirectly to humans, and therefore should be treated before rejection to natural water streams. As conventional wastewater treatment systems remain inefficient for treatment of these recalcitrant pollutants, the use of advanced oxidation processed is required. The degradation of the Orange G dye was studied using the photo-Fenton process. Results showed that the use of experimental kinetics rate constants to optimize the ratio R = [H2O2]/[Fe3+] constitutes a suitable way to minimize the occurrence of side reactions. An optimal molar ratio R of 13.8 was found allowing complete degradation of Orange G in 4 min and 93.41% total organic carbon (TOC) removal in 180 min. Based on detected intermediates and end-products, a plausible degradation mechanism of Orange G dye is proposed. Therefore, we demonstrated that the photo-Fenton process can be applied efficiently to the removal of toxic/persistent organic pollutants such as synthetic dyes from water.

STUDY OF FATE AND TRANSPORT OF EMERGENT CONTAMINANTS AT WASTE WATER TREATMENT PLANT

Contaminants of emerging concern such as pharmaceuticals, personal care products, bacteria, viruses, and pesticides are frequently found in waste water, groundwater, and surface waters. The search to find the sources of these compounds has routinely led to wastewater treatment plants (WWTPs) as an entry point of contaminants into the natural environment. The unknown effects of low concentrations of emerging contaminants in the aquatic ecosystem require scientists to study the occurrence, sources, fate, and transport of these compounds in wastewater treatment, to better understand and possibly identify mitigation opportunities. Reducing the contaminant levels in WWTP effluent helps minimize the contamination in lakes and rivers, which are both WWTP receiving waters as well as drinking water sources. Emerging contaminants end up in wastewater through several pathways including the disposal and use of consumer products, farm runoff, toxic spills, and excretion via the urine and feces of those consuming pharmaceuticals. The human body only metabolizes a percentage of each drug taken, expelling the rest into the municipal wastewater system. Another source is from consumer products such as soap, shampoo, disinfectant washes, and toothpaste which contain biologically active compounds that, when used, release these contaminants into the sewer system where they are then transported to a wastewater treatment plant (WWTP). Municipal wastewater treatment plants are not specifically designed to deal with the trace levels of emerging contaminates found in wastewater and many compounds pass through conventional treatment systems without removal. From the WWTP effluent, emerging contaminants are discharged into surface waters where they may have measurable effects on aquatic life at low concentrations. Once in surface waters, pharmaceuticals have been shown to interrupt the natural biochemistry of many aquatic organisms including fish and algae. Many of the problems associated with the removal of emerging contaminants from municipal wastewater stem from their low concentrations and chemical diversity, which make detection and analysis difficult. Low concentrations require extremely sensitive analytical equipment while the wide range of distinct chemical compounds necessitates techniques to identify many chemicals at once. Only recently have scientists become aware of the presence of some emerging contaminants in wastewater because analytical techniques able to detect them at the ng/l have only recently been developed. As laboratory procedures are developed and emerging contaminants can be accurately quantified, scientists are becoming increasingly able investigate the sources, removal pathways, and fate of pharmaceuticals in municipal wastewater. In addition to emerging contaminants, the potential entrance of prions into the wastewater system and their fate in wastewater treatment is an area of concern and a topic of interest in this study. A sampling program will implement to monitor the sources and fate of emerging contaminants in municipal wastewater treatment system. Laboratories will test for twelve different classes of emerging contaminants ranging from pharmaceuticals to flame-retardants. Hospitals, funeral homes, slaughterhouses and residential neighborhoods will monitor to determine possible point sources of contaminants into municipal sewer systems. Multiple locations within each wastewater treatment plant will monitor to trace the fate of each emerging contaminant class through the wastewater treatment process in an attempt to understand the fate removal pathways of each contaminant.

Photocatalytic oxidation of dairy effluent with UV lamp or UV light-emitting diode module and biological treatment processes

The objective of this study was to develop a novel and simple-operated treatment system for refining dairy farm effluent after conventional dairy wastewater treatment system. Experimental results showed that average removal efficiency of COD, BOD, and SS in the effluents of a dairy farm was 72, 98, and 79%, respectively, using a combined photocatalytic and biological reactors. Removal efficiency of calculated conductivity value seems to be closely related to the removal efficiency of NH4+, PO43−, and Mg2+ when using the photocatalytic UV lamp reactor only. However, average removal efficiency of COD, BOD, and SS in the dairy farm effluent was 53, 62, and 62%, respectively, with the photocatalytic UV LED reactor. In summary, removal efficiency of BOD, COD, SS, and EC in photocatalytically treated dairy farm effluent with UV lamp reactor was higher than that with photocatalytic UV LED reactor. In addition, removal efficiency of COD and BOD with a combined photocatalytic and biological treatment system was higher than that using a photocatalytic oxidation reactor only. Thus, the combined system can provide dairy cattle farmers to refine and recycle their effluents.

17α-Ethinylestradiol and 17β-estradiol removal from a secondary urban wastewater using an RBC treatment system.

The presence of micropollutants that include endocrine-disrupting compounds (EDC) in aquatic environments is currently one of the most relevant aspects of water quality due to their adverse effects on aquatic organisms and human health. From the several categories of EDC, 17β-estradiol (E2) is a natural hormone, which is prevalent in vertebrates, associated with the female reproductive system and maintenance of the sexual characters. 17α-Ethinylestradiol (EE2) is a synthetic hormone produced from the natural hormone E2 and is an essential component of oral contraceptives. These compounds are susceptible to bioconcentration and have high potential to bioaccumulation. Wastewater treatment plants are the main point source of E2 and EE2 into aquatic environments, but conventional wastewater treatment systems are not specifically designed for steroid removal. To overcome this problem, biological tertiary treatment may be a solution for the removal of emergent pollutants such as E2 and EE2. The main purpose of the present study is to provide a solution based on the optimization of a rotating biological contactor system to remove estrogens, specifically E2 and EE2, and to quantify their removal efficiency on different matrices, namely real wastewater and different synthetic wastewaters. All assays presented viable removal efficiencies for compound E2 with values always above 50%; real wastewater yielded the highest removal efficiencies. EE2 removal had better removal efficiencies with synthetic wastewater as feed solution, with removals above 15%, whereas the removal efficiency with real wastewater was inexistent.

Treatment and reuse of coalmine wastewater in Vietnam: application of microfiltration

Abstract Due to stringent local regulations and adverse environmental impacts, Vietnamese coal mining industries are under pressure to reuse the large volume of wastewater they produce. To this end, the aim of this study was to add microfiltration (MF) membranes after the conventional Vietnamese coalmine wastewater treatment systems (coagulation/sedimentation/filtration) to assess the feasibility of effluent reuse. The pilot-scale test was performed at a coalmine plant located in Quang Ninh province, Vietnam. Results indicate that precipitation with slaked lime (Ca(OH)2) and polyaluminum chloride (PACl) followed by sand filtration are important pre-treatment steps, prior to microfiltration. To achieve high Mn removals the sand in the filter had to be replaced by a KMnO4 coated sand. The MF membrane produced a stable and high quality effluent that meets the Vietnamese National Technical Regulations for Drinking Water quality (Fe < 0.5 mg/L, Mn < 0.3 mg/L, hardness <350 mg/L as CaCO3). Complete membrane recovery was achieved by sequential 24 h soakings in NaOCl, citric acid and a surfactant.

Removal of emerging contaminants using spent mushroom compost

Acetaminophen and sulfonamides are emerging contaminants. Conventional wastewater treatment systems fail to degrade these compounds properly. Mycoremediation, is a form of novel bioremediation that uses extracellular enzymes of white-rot fungi to degrade pollutants in the environment. In this study, spent mushroom compost (SMC), which contains fungal extracellular enzymes, was tested for acetaminophen and sulfonamides removal. Among the SMCs of nine mushrooms tested in batch experiments, the SMC of Pleurotus eryngii exhibited the highest removal rate for acetaminophen and sulfonamides. Several fungal extracellular enzymes that might be involved in removal of acetaminophen and sulfonamides were identified by metaproteomic analysis. The bacterial classes, Betaproteobacteria and Alphaproteobacteria, were revealed by metagenomic analysis and may be assisting with acetaminophen and sulfonamide removal, respectively, in the SMC of Pleurotus eryngii. Bioreactor experiments were used to simulate the capability of Pleurotus eryngii SMC for the removal of acetaminophen and sulfonamides from wastewater. The results of this study provide a feasible solution for acetaminophen and sulfonamide removal from wastewater using the SMC of Pleurotus eryngii.

Statistically-Based Comparison of the Removal Efficiencies and Resilience Capacities between Conventional and Natural Wastewater Treatment Systems: A Peak Load Scenario

Emerging global threats, such as climate change, urbanization and water depletion, are driving forces for finding a feasible substitute for low cost-effective conventional activated sludge (AS) technology. On the other hand, given their low cost and easy operation, nature-based systems such as constructed wetlands (CWs) and waste stabilization ponds (WSPs) appear to be viable options. To examine these systems, a 210-day experiment with 31 days of peak load scenario was performed. Particularly, we conducted a deliberate strategy of experimentation, which includes applying a preliminary study, preliminary models, hypothetical tests and power analysis to compare their removal efficiencies and resilience capacities. In contrast to comparable high removal efficiencies of organic matter—around 90%—both natural systems showed moderate nutrient removal efficiencies, which inferred the necessity for further treatment to ensure their compliance with environmental standards. During the peak period, the pond treatment systems appeared to be the most robust as they indicated a higher strength to withstanding the organic matter and nitrogen shock load and were able to recover within a short period. However, high demand of land—2.5 times larger than that of AS—is a major concern of the applicability of WSPs despite their lower operation and maintenance (O&M) costs. It is also worth noting that initial efforts on systematic experimentation appeared to have an essential impact on ensuring statistically and practically meaningful results in this comparison study.

Amoxicillin Removal from Aqueous Solutions Using US / H2O2 / NZVI process

Background and Aim: High concentrations of antibiotics are now detected in aquatic environments, reducing their quality. These compounds generally have a high toxicity and low biodegradability, and some are reported to have mutagenic and/or carcinogenic characteristics. Conventional treatment systems have proven inadequate to effectively remove this type of organic compound, largely due to its complex molecular structure. Therefore, it is necessary to remove an effective method for the removal of these compounds is suggested. The purpose of this study was to apply zero-valent iron nanoparticles in the presence of hydrogen peroxide and the process of sonolysis in the removal of antibiotic amoxicillin from aquatic environments. Materials and Methods: This research was carried out on a laboratory scale on a synthetic wastewater containing amoxicillin antibiotic that the effects of some parameters, such as ultrasound (35 and 130 kHz), contact time (30n150 min), concentration of hydrogen peroxide (0.5n3 ), concentrations of nZVI (0.06n0.2 g/L), pH (3n10), and concentration of AMX (45n100 mg/L) were investigated. Results: Optimum removal conditions were pH = 3, H2O2 concentration= 1, ultrasonic frequency= 130 kHz and nZVI concentration= 0.2 g/L. so that 97.3 of amoxicillin antibiotic after 150 min of reaction at pH=3, nZVI= 0.1 g/L, ultrasonic frequency= 130 kH, H2O2 =1 and 45 mg/L concentration of AMX was removed. Conclusion: The experiments showed the efficient removal of amoxicillin antibiotic in wastewater by Fentonrs oxidation process. The efficiency of this method can also be considered in eliminating other antibiotics resistant to biological treatment.

Use of the terrestrial weed Alternanthera ficoidea in treating greywater in soil-less SHEFROL® bioreactors.

The ornamental plant Alternanthera ficoidea (also named A. tenella), which is common and widespread throughout the tropics and is being increasingly regarded as an invasive, problematic weed, has been explored as a bioagent in greywater treatment. In the recently developed SHEFROL® bioreactor, it was seen to treat greywater of varying strengths (250-1,300 mg/L chemical oxygen demand, COD) quickly and substantially to the extent of 75-77%. Biological oxygen demand (BOD), nitrogen, phosphorus, suspended solids, and heavy metals copper, nickel, manganese, and zinc were also removed to the extents of 83.5, 94.9, 33.1, 27.0, 44.8, 27.5, 38.2, and 43.2%, respectively. As all this was achieved in a single pot, single step, and in a simple reactor operation, at hydraulic retention times of a mere 6 h, it shows the process to be several times more efficient as well as potentially less expensive than the conventional treatment systems which utilize macrophytes in tanks or constructed wetlands.

Full scale horizontal subsurface flow constructed wetlands to treat domestic wastewater by Juncus acutus and Cortaderia selloana

ABSTRACTIn the present study, a full scale horizontal subsurface flow constructed wetland was designed, constructed and operated to treat domestic wastewater of Kızılcaören village in Samsun city of Turkey. The total surface area of HSFCW was divided into equal parts. The effects of Juncus acutus L. and Cortaderia selloana (Schult.Schult.f.)Asch.&Graebn. on pollutants removal in HSFCWs were evaluated with the meteorological factors. The average removal efficiencies of J. acutus and C. selloana were determined as 60.3–57.7% for BOD; 24.2–38.9% for TN; 31.4–49.8% for OM; 35.4–43.3% for TP; 18.9–27.1% for orthophosphate; 24.4–28.7% for NH4-N; 29.5–37.2% for TSS; and 35.3–44.3% for TSM. Two-way ANOVA was applied to determine any difference for the removal of all parameters between the plant types and months on the mean values of contaminant removal. A correlation matrix of all parameters was determined. Subsurface flow constructed wetland was found quite efficient for the treatment of domestic wastewater in rural settlements. HSFCW is also more economical to install and maintain than a conventional wastewater treatment system while enhancing ecosystem services.

Study on Elemental Mercury Oxidation by Non-thermal Plasma with Calcium Chloride Enhancement

Converting of elemental mercury (Hg0) into oxidized mercury compounds is considered to be an effective method for prompting mercury removal of conventional flue gas treatment systems. The technology of non-thermal plasma (NTP) with CaCl2 treatment was utilized to oxidize Hg0 in this paper. The effects of input energy and different flue gas components like O2, NO and SO2 on Hg0 oxidation were investigated. The results showed that the Hg0 oxidation efficiency with CaCl2 treatment was increased obviously compare with single NTP treatment, and would be more than 90% when the input energy was 120 J/L. The O2 in simulated flue gas played an important role for mercury oxidation. The Hg0 oxidation efficiency and O3 outlet concentration were increased with the increase of O2 content. However, both NO and SO2 inhibited Hg0 oxidation due to their competitive consumption of O3 and O. Compare with single NTP technology, the effects of NO and SO2 on Hg0 oxidation under NTP with CaCl2 treatment were decreased obviously. The technology of Temperature-Programmed Decomposition and Desorption was utilized to analyze the mercury speciation adsorbed or deposited on AC and CaCl2 surface. The results concluded that the main Hg0 oxidation products by NTP with CaCl2 treatment were HgO, Hg2O and HgCl2, which indicated that the chlorine of CaCl2 surface was the main reason for enhancement of Hg0 oxidation.

Highly Biocompatible, Underwater Superhydrophilic and Multifunctional Biopolymer Membrane for Efficient Oil–Water Separation and Aqueous Pollutant Removal

Conventional wastewater treatment systems generally require multiple steps and complex procedures to remove aqueous pollutants and oil contaminants from polluted water. Herein, we fabricate an underwater superoleophobic membrane by cross-linking konjac glucomannan on pristine fabrics, demonstrating that the concept of oil–water separation and the principle of aqueous pollutant removal can be integrated. Such biopolymer-modified fabric not only separates oil–water mixtures with high efficiency (up to 99.9%), but also exhibits the intriguing characteristic of removing water-soluble pollutants (including polyaromatic dyes and heavy metal ions). As a proof of concept, the synthetic wastewater purified with biopolymer membranes was used to cultivate and irrigate pinto beans, causing no observable deleterious effect on seed germination and growth. These results further confirm the biocompatibility and effectiveness of biopolymer membranes, offering an encouraging solution to challenges including wastewater trea...

Removal of Organic Matter Using Phytoextraction Technique with the Heliconia psittacorum and Typha angustifolia Species in Swine Production Systems

Wastewater generated at the MVZ Academic Research Unit (NAIP), located at the University of La Paz in Barrancabermeja Santander. It was an environmental problem, due to the non-compliance with the values of the pollutant load. For the NAIP, wastewater treatment, there was a conventional system, which was a septic tank, the heat was not at its peak, the lack of maintenance was evident and so the poor state in which it was. Therefore, it is urgent and necessary to fix and complement the system. The methodology used in this project was based on the consultation of different sources of bibliographical information and field observation, in order to analyze everything related to the optimization process of the wastewater treatment system of the NAIP and generate positive solutions in Pro to minimize the environmental problem. This project contemplated as the first phase, the evaluation of the initial state of the system, where parameters were analyzed in laboratory in accordance with Resolution 631 of 2015; These results show that this system improves the increase of the percentage of removal required by the environmental regulations, so that the optimization alternatives were proposed and implemented in the different stages of this treatment system, which plants are found in this work of degree. After knowing the initial state of the treatment system, a pre-treatment was designed and implemented, which is a screening system, optimized and adapted to a septic tank to be used as a primary treatment, it now works as a sedimentation tank, And as a secondary treatment we proposed a biological alternative, which are two artificial subsurface flow wetlands in series with Heliconia psittacorum and Typha angustifolia, completing and complementing the conventional treatment system found. Once the system is finished, follow the following respectful for five months, recording the adaptation of the plants, checking the operation of the tank and performing the cleaning of the screening system. At the end of this adaptation period, the following evaluation of the efficiency of the system was carried out, checking its decontamination range, which was 96% to 99% for removal of BOD5, COD, SST, SSED and GA; Obtaining decreases of DB5 and COD from 6280 mg O2/L and 13007 mg O2/L up to 25 mg O2/L and 67 mg O2/L (respectively).

The use of activated carbon for the removal of pharmaceuticals from aqueous solutions: a review

The presence of pharmaceutically active compounds in surface and ground water is of concern due to the adverse effects they may have on human health, aquatic life, and the environment, emphasizing the importance of their removal from the water compartment. Activated carbon adsorption has proven to be effective for the removal of several types of inorganic and organic contaminants either as a stand-alone polishing step or in combination with other conventional and advanced water and wastewater treatment systems. This paper discusses the current status of the removal of pharmaceuticals from water using activated carbon derived from numerous precursors, providing an in-depth review of the multitude of factors (adsorbent properties, adsorbate properties, operating conditions) affecting the adsorption process, from the preparation of the activated carbon to its regeneration. A critical assessment of the existing literature is presented, highlighting research and development needs that may ultimately lead to a more comprehensive and sustainable use of activated carbon for the removal of pharmaceuticals from the water environment.

Lithography performance and environmental compatibility of PFOS-free photoacid generators

Photoacid generators (PAGs) with environmentally friendly cores and partially fluorinated sulfonate salts have been synthesized and studied. The cores were based on naturally occurring compounds such as cholesterol and glucose and were functionalized with a biodegradable octafluoro-3-oxapentanesulfonate. These PAGs were soluble in common spinning solvents and lithographically characterized with poly(styrene-co-4-hydroxy-styrene-co-tert-butylacetate) photoresist, and they showed higher resolution for photoresist applications than a perfluorooctane sulfonate (PFOS)-based triphenylsulfonium salt PAG, capable of patterning 50 nm dense lines. In addition, microbial bioassays confirmed that the newly developed PAG compounds can be broken down by microorganisms commonly found in conventional wastewater treatment systems. The biodegradation potential of the new PAGs presents a distinct advantage compared to that of PAG perfluorinated structures such as PFOS and perfluorobutane sulfonate, which are highly resistant to biodegradation and difficult to treat by conventional processes. The excellent performance and environmental compatibility of these PAGs make them promising candidates for use in high-resolution lithography systems.

Applicability of energy-positive net-zero water management in Alaska: technology status and case study.

Challenges of water and wastewater management in Alaska include the potential need for above-grade and freeze-protected piping, high unit energy costs and, in many rural areas, low population density and median annual income. However, recently developed net-zero water (NZW), i.e., nearly closed-loop, direct potable water reuse systems, can retain the thermal energy in municipal wastewater, producing warm treated potable water without the need for substantial water re-heating, heat pumping or transfer, or additional energy conversion. Consequently, these systems are projected to be capable of saving more energy than they use in water treatment and conveyance, in the temperate USA. In this paper, NZW technology is reviewed in terms of potential applicability in Alaska by performing a hypothetical case study for the city of Fairbanks, Alaska. Results of this paper study indicate that in municipalities of Alaska with local engineering and road access, the use of NZW systems may provide an energy-efficient water service option. In particular, case study modeling suggests hot water energy savings are equivalent to five times the energy used for treatment, much greater savings than in mid-latitudes, due largely to the substantially higher energy needed for heating water from a conventional treatment system and lack of need for freeze-protected piping. Further study of the applicability of NZW technology in cold regions, with expanded evaluation in terms of system-wide lifecycle cost, is recommended.

Combination of low-pressure UF membranes with conventional water treatment systems

The purpose of the study was to improve drinking water quality of conventional treatment processes by combining with UF-membrane systems. Performances of two membrane systems were evaluated in two different full-scale conventional water treatment plants in Istanbul. Low-pressure UF membranes were combined after settling and filtration units of Büyükçekmece and Emirli water treatment plants. Low-pressure UF systems were operated under vacuum and pressure conditions. The experimental results indicated that combining UF systems enhanced drinking water quality with respect to turbidity, TOC and UV254 removal. In all cases, vacuum-driven UF membranes provided higher treatment performance and low energy consumption comparing to pressure-driven system. Combination with UF membranes also reduced disinfection by-products.

Fecal contamination of soil and water in sub-Saharan Africa cities: The case of Addis Ababa, Ethiopia

Only a small proportion of Addis Ababa is served by conventional sewerage treatment systems. Most of the city relies upon on-site sanitation, while open defecation remains a common practice, especially in slum areas. This paper provides evidence of environmental pollution related to inadequate sanitation using a range of physicochemical and fecal contamination indicators and a mix of surveys of pit latrine contents, soils and water sources. Some water sources, including deep wells, show indications of fecal contamination, and soils are widely contaminated with the parasitic worm, Ascaris lumbricoides. Analysis of pit latrine contents shows a significant reduction in the number of A. lumbricoides ova with depth, but levels of ova at even the bottom of the pit suggest the need for proper sludge treatment. Wider awareness of environmental pollution gleaned from this research is intended to inform policy makers and their prioritization of actions to improve urban sanitation.

Spatiotemporal variability of drinking water quality and the associated health risks in southwestern towns of Ethiopia.

The failure to provide safe drinking water services to all people is the greatest development setback of the twenty-first century including Ethiopia. Potential pollutants from various sources are deteriorating drinking water quality in different seasons, and associated health risks were not clearly known. We determined seasonal and spatial variations of urban drinking water characteristics and associated health risks in Agaro, Jimma, and Metu towns, Southwest Ethiopia. Seventy-two samples were collected during dry and rainy seasons of 2014 and 2015. The majority (87.4%) of physicochemical parameters was found within the recommended limits. However, free residual chlorine in Jimma and Agaro town water sources was lower than the recommended limit and negatively correlated with total and fecal coliform counts (r=-0.585 and -0.638). Statistically significant differences were observed at pH, turbidity, and total coliform between dry and rainy seasons (p<0.05). A Kruskal-Wallis H test revealed a statistically significant difference in electrical conductivity, total hardness, fluoride, iron, and fecal coliform across the study towns (p<0.05). The Agaro town water source was the highest in fluoride concentration (3.15mg/l). The daily exposure level for high fluoride concentration in Agaro town was estimated between 0.19 and 0.41mg/kgday, and the average cumulative hazard index of fluoride was >3.13 for all age groups. Water quality variations were observed in all conventional water treatment systems in the rainy season, and further research should focus on its optimization to safeguard the public.

Psychoactive drugs: occurrence in aquatic environment, analytical methods, and ecotoxicity-a review.

This review focused on seven psychoactive drugs being six benzodiazepines (alprazolam, bromazepam, clonazepam, diazepam, lorazepam, and oxazepam) and one antidepressant (citalopram) widely consumed by modern society and detected in different aqueous matrices (drinking water, surface water, groundwater, seawater, estuary water, influent and effluent of wastewater treatment plants). The review included 219 selected scientific papers from which 1642 data/entries were obtained, each entry corresponding to one target compound in one aqueous matrix. Concentrations of all investigated drugs in all aqueous matrices varied from 0.14 to 840,000ngL-1. Citalopram presented the highest concentrations in the aqueous matrices. Based on the Wilcoxon-Mann-Whitney test, differences between wastewater influents and effluents were not significant for most wastewater categories, suggesting that conventional wastewater treatment systems as such do not remove or remove partially these compounds. High-income countries showed much lower concentrations in surface water than the group formed by upper-middle-, lower-middle-, and low-income countries. Regarding analytical methods, solid-phase extraction (SPE) was by far the most used extraction method (83%) and performance liquid chromatography (HPLC) (73%) coupled to mass spectrometry (99%) the most common analytical method. Changes in behavior and in survival rates were the most common effects reported on bioindicators (aquatic species) due to the presence of these drugs in water. Concentrations of psychoactive drugs found in surface waters were most of the time within the range that caused measurable toxic effects in ecotoxicity assays.