Safe Wastewater Research Articles

SDG 6 progress analyses in sub-Saharan Africa from 2015–2020: the need for urgent action

This study used data from various international databases to track the progress of SDG 6 target indicators in sub-Saharan Africa (SSA) region between 2015 and 2020. Findings showed that although minimal positive progress was realized in the evaluation period, more than half of SSA residents had no access to safe drinking water services, improved sanitation facilities, hygiene services and safe wastewater treatment. The computed SDG 6 profile index conformed with the trend of indicators as progress of the region to the goal’s realization was rated as medium–low. The trend was further compounded by limited data, preferential access to water and sanitation services to the urban rich and poor monitoring of progress. The analysis also noted that despite these challenges the region was putting concerted efforts to promote transboundary cooperation in water management and had 6% of water stressed resources. The study recommended on the need to revamp water data collection and monitoring efforts to enable decision-making and planning on management actions, use of technology to treat and reuse wastewater as well as device new sources of water, enhanced participation of communities in water projects and improved water use efficiency to steer progress towards SDG 6 realization in SSA region.

Toxicity removal from contaminated water by constructed wetlands assessed using multiple biomarkers in human stem cell assays

Constructed wetlands (CWs) have been developed rapidly as a sustainable water treatment technique. However, the capability of CWs for remediating the contaminated water based on toxicity assessment remains largely unknown. Four surface flow CWs and two integrated surface-subsurface flow CWs, from five cities in central and eastern region of China were evaluated, concerning the adverse effects of effluents and the toxicity reduction efficiency. Human bone marrow mesenchymal stem cells (hBMSCs) were employed as a human relevant in vitro model. The influent extractions caused cytotoxicity in a dose-dependent manner. The non-cytotoxic dilutions of the influents enhanced the genotoxicity marker γ-H2AX and reactive oxygen species levels. In addition, the influent repressed the osteogenic and neurogenic differentiation, and stimulated the adipogenic differentiation. Cytotoxicity of the contaminated water was reduced by 54 %–86 % after treatment with CWs. CWs were effective to remove part of the sub-lethal effects, with lower reduction than cytotoxicity. The integrated biomarker response (IBR) value of the effluents from the six CWs is lower than that of four secondary and one tertiary wastewater treatment plants. The IBR of the six CWs influents were in the range of 8.6–10.6, with a reduction of 15–50 % after the pollution restoration in CWs. The two integrated surface-subsurface flow CWs achieved higher IBR removal than the four surface flow CWs, possibly due to improved treatment effects by the combined systems. Cytotoxic and genotoxic effects of polar fractions in the CW effluents were stronger than the medium-polar and the non-polar fractions. Besides, PPARγ agonists present in the effluents played crucial roles and ERα agonists may make modest contributions. The present study enhances understanding of the role of CWs in achieving safe wastewater reclamation and provides evidence for further improving toxicity reduction in CWs performance.

Evaluation of virus removal in membrane bioreactor (MBR) and conventional activated sludge (CAS) processes based on long-term monitoring at two wastewater treatment plants

The membrane bioreactor (MBR) process always offers better wastewater treatment than conventional activated sludge (CAS) treatment. However, the difference in their efficacy of virus reduction remains unknown. To investigate this, we monitored virus concentrations before and after MBR and CAS processes over 2 years. Concentrations of norovirus genotypes I and II (NoV GI and GII), aichivirus (AiV), F-specific RNA phage genotypes I, II, and III (GI-, GII-, and GIII-FRNAPHs), and pepper mild mottle virus (PMMoV) were measured by a quantitative polymerase chain reaction (qPCR) method at two municipal wastewater treatment plants (WWTPs A and B) in Japan. Virus concentration datasets containing left-censored data were estimated by using both maximum likelihood estimation (MLE) and robust regression on order statistics (rROS) approaches. PMMoV was the most prevalent at both WWTPs, with median concentrations of 7.5 to 8.8 log10 copies/L before treatment. Log10 removal values (LRVs) of all viruses based on means and standard deviations of concentrations before and after treatment were consistently higher following MBR than following CAS. We used NoV GII as a model pathogen in a quantitative microbial risk assessment of the treated water, and we estimated the additional reductions required following MBR and CAS processes to meet the guideline of 10−6 DALYs pppy for safe wastewater reuse.

Assessment of wastewater impact on a natural reservoir in Kyrgyzstan

Introduction: Anthropogenic activities artificially increase the concentration of toxic substances in surface reservoirs by discharging polluted water back into the natural environment. Maximum risks for aquatic ecosystems are observed in regions with limited wastewater treatment, which includes Kyrgyzstan. The purpose of the work – research and analysis of factors of pollution of natural reservoirs of Kyrgyzstan by wastewater, consequences for regional aquatic ecosystems and public health, and search for optimal solutions to minimise destructive pollution. Material and Methods: The research was conducted using general scientific methods of cognition, in particular, system analysis, synthesis, generalisation, and concretisation. Results and Discussion: In the course of the research the ecological state of natural water resources of Kyrgyzstan, into which wastewater is discharged, the dynamics of pollution of the aquatic environment depending on various factors of influence is analysed, optimal and feasible to implement measures to reduce the adverse effects of wastewater on the state of natural reservoirs and public health, and improve the overall environmental situation in the region are developed. In addition, the possibilities of applying modern management and technological measures to minimise the content of pollutants in wastewater, based on the synergy of environmental safety and economic efficiency, with the introduction of modern innovative systems of control and monitoring of environmental pollution have been explored. Conclusion: It is established that there is no safe wastewater, therefore, optimisation of the water use and water treatment system in Kyrgyzstan involves the application of an ecosystem approach and the introduction of integrated water resources management.

Research on an eco-safe filtration plant for wastewater treatment made of natural raw materials

Purpose. To develop a new eco-safe filtration plant for wastewater treatment based on natural and secondary raw materials, which will allow rational use of natural resources with further mathematical modeling of hydrodynamics of mixing treated wastewater in bioponds to predict removal of residual concentrations from the filter. Methodology. A complex of modern methods of theoretical and experimental research was used to solve the tasks. Concentration of pollutants was determined using methods of atomic adsorption spectroscopy, titrimetry and gravimetric methods, as well as pyrometric analysis. A laboratory installation was created, which included a receiving tank, a filter column, and a tank for collecting purified wastewater. Prediction of distribution and mixing of treated effluent in bioponds was carried out using mathematical and computer software. Findings. An environmentally safe filtration plant (containing sand, fallen leaves of linden, poplar, and plastic residues separated by a polymer mesh) was created to purify wastewater from suspended substances and nitrates. Kinetics of changes in concentration of suspended solids and nitrates in urban wastewater were studied. When using the filtration plant, concentration of suspended solids decreased by 85–92 %. Concentration of nitrates in purified water processed with such a plant is reduced from 12 to 0.25–0.05 mg/dm3. A mathematical model concerning distribution of purified water in a biopond was obtained, which allows predicting possible migration distributions of residual concentrations in purified water during its natural movement downstream. Originality. For the first time, influence of the species origin of fallen leaves on the performance indicators of wastewater filtration plant of urban sewage treatment constructions was investigated, which made it possible to substantiate a new way of disposal of this type of waste. For the first time, it was established that wastewater treatment using an eco-safe filtration plant based on natural and secondary raw materials, containing layers of sand, fallen oak, linden, and poplar leaves, gives an opportunity to reduce contents of suspended solids in wastewater by 1.5 times of the maximum permissible concentration; and such treatment also reduces concentration of nitrates by 4 times from the initial level. Pollutants from wastewater are mechanically fixed in pockets (microcracks, cracks) of fallen leaves, formed during drying of leaves, which is explained by hardening of intercellular spaces with formation of a specific geometry of holes. For the first time, mathematical modeling of purified wastewater movement in a biological pond with a complex geometry was performed, which allows estimating the concentration of the pollutant at its outlet from the pond. Practical value. The created environmentally safe wastewater filtration plant gives an opportunity to perform not only filtering, but also an effective biological purification of wastewater from nitrates on the surface of layers of fallen leaves. The wide use of the proposed installation will allow attracting plastic of polyethylene bottles used in everyday life as a secondary raw material. Based on the proposed mathematical model of movement of purified liquid containing residual concentrations of pollutants, it is possible to carry out qualitative forecasting and optimization of the process of cascade wastewater treatment at industrial and economic enterprises.

Constructed Wetlands as Nature-Based Solutions for Wastewater Treatment in the Hospitality Industry: A Review

The hospitality industry is increasing its awareness of how the integration of nature-based solutions can decrease its environmental impact while maintaining or increasing the service level of the sector. Constructed wetlands (CWs) constitute a promising sustainable solution for proper in situ domestic wastewater treatment. This literature review elucidates the status of CWs implementation in the hospitality industry to help foster the exchange of experiences in the field and deliver examples of approaches in different contexts to support future applications of this technology. Most of the studies reported in the literature were conducted in Europe, but studies emanating from Asia and South America are also available. The design of CWs, the horizontal and vertical subsurface flow CWs (HSFCW, VSFCW), and hybrid systems have been reported. The average removal efficiencies of the systems ranged from 83 to 95% for biochemical oxygen demand, 74 to 94% for chemical oxygen demand, 78 to 96% for total suspended solids, 75 to 85% for ammonium, 44 to 85% for ammonia, 50 to 73% for nitrate, 57 to 88% for total Kjeldahl nitrogen, 51 to 58% total nitrogen, and 66 to 99% for total phosphorus. The majority of the systems were implemented as decentralized treatment solutions using HSFCWs, with the second most common design being the hybrid CW systems in order to reduce area requirements, increase treatment efficiency, and prevent clogging. Overall, CWs are a promising sustainable solution which may support access to adequate sanitation worldwide as well as safe wastewater recycling and reuse, leading to more sustainable tourist destinations.

Tofu by-product soy whey substitutes urea: Reduced ammonia volatilization, enhanced soil fertility and improved fruit quality in cherry tomato production

Soy whey is an abundant, nutrient-rich and safe wastewater produced in tofu processing, so it is necessary to valorize it instead of discarding it as sewage. Whether soy whey can be used as a fertilizer substitute for agricultural production is unclear. In this study, the effects of soy whey serving as a nitrogen source to substitute urea on soil NH3 volatilization, dissolved organic matter (DOM) components and cherry tomato qualities were investigated by soil column experiment. Results showed that the soil NH4+-N concentrations and pH values of the 50% soy whey fertilizer combined with 50% urea (50%-SW) and 100% soy whey fertilizer (100%-SW) treatments were lower than those of 100% urea treatment (CKU). Compared with CKU, 50%-SW and 100%-SW treatments increased the abundance of ammonia oxidizing bacteria (AOB) by 6.52–100.89%, protease activity by 66.22–83.78%, the contents of total organic carbon (TOC) by 16.97–35.64%, humification index (HIX) of soil DOM by 13.57–17.99%, and average weight per fruit of cherry tomato by 13.46–18.56%, respectively. Moreover, soy whey as liquid organic fertilizer reduced the soil NH3 volatilization by 18.65–25.27% and the fertilization cost by 25.94–51.87% compared with CKU. This study provides a promising option with economic and environmental benefits for soy whey utilization and cherry tomato production, which contributes to the win-win effectiveness of sustainable production for both the soy products industry and agriculture.

Removal of Steroid Estrogens and Total Nitrogen by Denitrification Biofilter with UV/Peracetic Acid Pretreatment: Performance, Microbial Characteristics, and Mechanism

Total nitrogen (TN) and steroid estrogens (SEs) in secondary effluent challenge widely used denitrification biofilter (DNBF) in achieving the regulated limit value in water reuse, as well as toxicity reduction. Herein, we first use UV/peracetic acid (PAA) as a pretreatment of DNBF for advanced wastewater treatment, followed by an evaluation of its effectiveness in removing TN and SEs from low C/N wastewater. The results showed that UV/PAA-biofilter significantly improved the removal of TN and SEs compared to conventional DNBF. Under the conditions of [PAA]0 = 15 mg/L, UV = 1250 μW/cm2, photoreaction time of 30 min, and biofilter hydraulic retention time (HRT) = 3 h, the SE removal rates could reach more than 95% and the effluent TN maintained less than 10 mg/L. Furthermore, UV/PAA-biofilter improved the reduction of estrogenic activity but not of acute toxicity. Increased extracellular polymeric substance (EPS) content and relative abundance of napA gene were observed in DNBF pretreated with UV/PAA, and Azospira was identified as the core microorganism for denitrogenation. Our investigations confirmed the feasibility of the UV/PAA-biofilter to remove SEs and TN simultaneously, highlighting the great potential of its application in the advanced purification of secondary effluent for safe wastewater reuse.

Modeling slow sand filtration for sustainable safe wastewater reuse in agriculture in Draa Sfar mine region (Marrakech, Morocco)

Modeling slow sand filtration for sustainable safe wastewater reuse in agriculture in Draa Sfar mine region (Marrakech, Morocco)

Next-generation Sequencing for Surveillance of Antimicrobial Resistance and Pathogenicity in Municipal Wastewater Treatment Plants.

The World Health Organization (WHO) ranks antimicrobial resistance (AMR) and various pathogens among the top 10 health threats. It is estimated that by 2050, the number of human deaths due to AMR will reach 10 million annually. On the other hand, several infectious outbreaks such as SARS, H1N1 influenza, Ebola, Zika fever, and COVID-19 have severely affected human populations worldwide in the last 20 years. These recent global diseases have generated the need to monitor outbreaks of pathogens and AMR to establish effective public health strategies. This review presents AMR and pathogenicity associated with wastewater treatment plants (WWTP), focusing on Next Generation Sequencing (NGS) monitoring as a complementary system to clinical surveillance. In this regard, WWTP may be monitored at three main points. First, at the inlet (raw wastewater or influent) to identify a broad spectrum of AMR and pathogens contained in the excretions of residents served by sewer networks, with a specific spatio-temporal location. Second, at the effluent, to ensure the elimination of AMR and pathogens in the treated water, considering the rising demand for safe wastewater reuse. Third, in sewage sludge or biosolids, their beneficial use or final disposal can represent a significant risk to public health. This review is divided into two sections to address the importance and implications of AMR and pathogen surveillance in wastewater and WWTP, based on NGS. The first section presents the fundamentals of surveillance techniques applied in WWTP (metataxonomics, metagenomics, functional metagenomics, metaviromics, and metatranscriptomics). Their scope and limitations are analyzed to show how microbiological and qPCR techniques complement NGS surveillance, overcoming its limitations. The second section discusses the contribution of 36 NGS research papers on WWTP surveillance, highlighting the current situation and perspectives. In both sections, research challenges and opportunities are presented.

A sustainable competitive supply chain network design for a green product under uncertainty: A case study of Iranian leather industry

The leather industry typically generates a large amount of wastewater. Leather production requires large quantities of freshwater and various chemicals are added to the water at every stage of production. The absence of proper regulatory bodies and specialized treatment plants to recycle the wastewater add to the environmental hazards caused by the industry. Due to the problems cited above and the significant cost of safe wastewater disposal, numerous manufacturers illegally discharge their chemically polluted wastewater, causing immeasurable damage to the environment and public health. Governments' failure to adopt suitable taxation and subsidy policies further aggravates the crisis and discourages manufacturers from transitioning toward sustainable production practices. As a result, the majority of manufacturers are on the brink of bankruptcy. In this study, we propose a model for a leather industry supply chain that incorporates the three pillars of sustainability which include economic viability, environmental protection, and social equity. The proposed model features flexible governmental policies and enacts a Stackelberg competition between the producers and retailers under both certain and uncertain conditions in the context of the Iranian leather industry to ensure maximum customer satisfaction. To verify the applicability of the model, it was applied to a real-world case study under uncertainty. In the end, the validity of the model was confirmed when the results were approved by a panel of industry experts.

Comparing effects of default nudges and informing on recycled water decisions.

Despite a serious need for sustainable alternative water supplies in many parts of the world, public opposition remains a barrier to implementing solutions such as safe wastewater recycling schemes. Here, we compared two strategies to increase acceptance of recycled water: default nudges and informing choices. Experiment 1 (N = 81) showed that defaults increased acceptance of recycled water. Experiment 2 (N = 142) replicated the effect but also indicated that weak educational interventions (simple infographics) interacted with confidence, such that those who switched from the default option had measurably higher confidence in their choice when given the infographic. Experiment 3 (N = 146) suggested that in a college undergraduate sample, strong educational interventions (educational videos) eliminated the effect of nudges on recycled water acceptance, increased acceptance, increased knowledge of recycled water, and also interacted with confidence in the same way observed in Experiment 2. Experiment 4 (N = 271) showed that strong educational interventions can also increase recycled water acceptance in an MTurk sample. Since both education and defaults may be effective, we suggest that future work would benefit from cost-benefit analyses between strategies. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Assessment of the stability and reliability of the water treatment plant in Nowy Sącz using control cards

The subject of the study was to evaluate the stability and reliability of the sewage treatment plant in Nowy Sącz. The scope of the analysed indicators included the main indicators of wastewater contamination: BOD5 (biochemical oxygen demand), CODCr (chemical oxygen demand), total suspended solids (TSS), total nitrogen (Ntot), and total phosphorus (Ptot). The operation stability of the sewage treatment plant in Nowy Sącz was determined on the basis of control cards x for 24 observations made in the period 2018–2019 (2 years). Moreover, the technological reliability of the tested sewage treatment plant (WN) was determined based on the values of the analysed pollution indicators in treated sewage and their permissible values. On the basis of the conducted analyses, full stability of the removal process of most of the analysed contaminants was found. In no case was there any crossing of the control lines, only a single grouping of samples above the help line in the case of total nitrogen, which could indicate a periodical disturbance in the stability of the removal process of this compound. On the basis of the obtained values of the reliability coefficient, which were below WN = 1.00, reliable operation of the analysed facility was found, with a high degree of reduction (ƞ) of the analysed pollutants. The method of determining the technological reliability and stability of the treatment plant with the use of control cards is an effective and easy tool for detecting any disturbances and instabilities in the processes taking place in the tested facility. It enables the operator to take quick action to remove them, thus ensuring a safe wastewater treatment process for the environment and human health.

The WHO Guidelines for Safe Wastewater Use in Agriculture: A Review of Implementation Challenges and Possible Solutions in the Global South

Globally, the use of untreated, often diluted, or partly treated wastewater in agriculture covers about 30 million ha, far exceeding the area under the planned use of well-treated (reclaimed) wastewater which has been estimated in this paper at around 1.0 million ha. This gap has likely increased over the last decade despite significant investments in treatment capacities, due to the even larger increases in population, water consumption, and wastewater generation. To minimize the human health risks from unsafe wastewater irrigation, the WHO’s related 2006 guidelines suggest a broader concept than the previous (1989) edition by emphasizing, especially for low-income countries, the importance of risk-reducing practices from ‘farm to fork’. This shift from relying on technical solutions to facilitating and monitoring human behaviour change is, however, challenging. Another challenge concerns local capacities for quantitative risk assessment and the determination of a risk reduction target. Being aware of these challenges, the WHO has invested in a sanitation safety planning manual which has helped to operationalize the rather academic 2006 guidelines, but without addressing key questions, e.g., on how to trigger, support, and sustain the expected behaviour change, as training alone is unlikely to increase the adoption of health-related practices. This review summarizes the perceived challenges and suggests several considerations for further editions or national adaptations of the WHO guidelines.

Activated Carbon and Coconut Coir with the Incorporation of ABR System as Greywater Filter: The Implications for Wastewater Treatment

Greywater refers to wastewater generated from domestic activities, which do not contain fecal contamination. Therefore, this study aims to treat greywater in Makassar city to speed up the water cycle and enable reuse, as an environmental conservation strategy. The water parameters measured were pH, Turbidity, Total Suspended Solid (TSS), Biological Oxygen Demand (BOD), and Chemical Oxygen Demand (COD). According to the results, the greywater’s BOD, COD, and TTS contents were 49.98 to 54.88 mg/L, 509 to 655 mg/L, and 404.40 to 464.65 mg/L, respectively, all of which exceed WHO wastewater quality standards. The use of a wastewater treatment installation comprising a combination of Activated Carbon (AC) and Coconut Coir (CC) with the incorporation of the Anaerobic Baffle Reactor (ABR) system as a greywater filter successfully reduced the city’s greywater pollution. In addition, the new BOD content fulfills the environmentally safe wastewater standards, while the new COD and TSS contents were 152 mg/L to 184 mg/L and 59.68 mg/L to 77.42 mg/L, respectively, which are close to the WHO domestic wastewater quality standards.

Izazovi u snabdevanju vodom, sanitaciji i higijeni u okviru agende održivog razvoja do 2030. u Republici Srbiji

The 2030 Agenda for Sustainable Development is a global strategic framework of seventeen goals to be achieved within a decade. The recent Progress Report shows that Serbia made steps toward reaching targets within the sustainable development goal (SDG) 6 related to the availability and sustainable management of water and sanitation for all. While 82% of the population in urban areas has access to safe drinking water, the country needs to regulate water supply systems and individual water sources in rural areas. Hygienically correct water is a prerequisite for preventing the transmission of fecal-oral diseases. The biggest challenge under the SDG 6 is safe sanitation management, available to 18% of the population. A national on-site study in Serbia identified issues with the containment, emptying, transport, and final disposal of excreta. The key actions must be connecting households to public sewers, regulating management of septic tanks, and investing in environmentally safe wastewater treatment plants. The Progress Report claims that 98% of the population has access to hand-washing facilities with soap and water within the household. This highlights the importance of providing hygienically correct water not only for drinking and sanitation, but for personal hygiene, hand washing, laundry, cleaning, and other household needs. Water, sanitation, and hygiene (WASH) are of prime importance in public institutions. Several studies in Serbia reported inadequate sanitary-hygienic conditions in schools and healthcare facilities in rural areas. WASH in schools and healthcare facilities not only contributes to reducing the spread of infectious diseases but also supports the healthy habits of pupils and patients and promotes the good health of the entire population. We propose the public health system ensure long-term supervision over water supply, sanitation services, and hygiene in households, schools, and healthcare facilities through continuous monitoring programs in line with the indicators and targets of the 2030 Agenda.

Influence of the Nb content and microstructure of sitinakite-type crystalline silicotitanates (CSTs) on their Sr2+ and Cs+ sorption properties

Radioactive wastewater contaminated with 137Cs and 90Sr are produced at different stages of the nuclear fuel cycle. Transferring these radionuclides to a stable solid matrix is crucial for safe wastewater management and long-term storage. Sitinakite Crystalline silicotitanates (CSTs) are among the most selective mineral ion exchangers for Cs and/or Sr depending on the pH of the medium and the CST chemical composition (Nb doping). To better understand how their microstructure affects their sorption properties, CSTs with different morphologies (consisting of submicronic to micronic particles) and Nb contents (from 0% to 25%) were synthesized and characterized in terms of their Sr2+ and Cs+ sorption properties at moderately basic pH. The Sr2+/Na+ and Cs+/Na+ equilibrium exchange diagrams obtained highlight the presence of two kind of sorption sites with different selectivities and sorption capacities. The first, kind of site, highly selective for Sr and less selective for Cs at moderately basic pH, was attributed to “tunnel” sites in the CST structure. The second one, less selective for Sr and Cs, seems to be a surface site. Although Nb doping was found to promote Cs sorption and hinder Sr sorption at moderately alkaline pH, the accessibility and selectivity of these two sites was found to depend more strongly on the microstructure of the CSTs. Results indicate that the more highly crystalline, micronic particles, with fewer structural defects, are more selective for Sr, but that the larger specific surface areas (greater number of surface sites) afforded by the submicronic particles are associated with larger sorption capacities.

Photocatalytic ZnO-Assisted Degradation of Spiramycin in Urban Wastewater: Degradation Kinetics and Toxicity

The removal of contaminants of emerging concern from urban wastewater treatment plants (WWTPs) remains a challenge to promote safe wastewater reuse practices. Macrolides are the most abundant antibiotics detected in untreated wastewater and their concentration in WWTPs effluents is only partially reduced by conventional treatments. Among several advanced oxidation processes (AOPs), photocatalysis has demonstrated the capability to effectively remove pharmaceuticals from different aqueous matrices. Recently, ZnO has emerged as an efficient, promising, and less expensive alternative to TiO2, due to its photocatalytic capability and attitude to exploit better the solar spectrum than TiO2. In this study, the behaviors of ZnO photocatalysis were evaluated using a representative macrolide antibiotic, spiramycin (SPY), in aqueous solutions and urban wastewater. After 80 min of photocatalysis, 95–99% removal of SPY was achieved at 1 g L−1 ZnO concentrations in aqueous solutions and wastewater, respectively. After treatment, the effluent toxicity, evaluated using the bacterium Aliivibrio fischeri, the green alga Raphidocelis subcapitata, and the crustacean Daphnia magna ranged between slight acute and high acute hazard. Filterable and ultrafilterable Zn concentrations were quantified in treated effluents and shown to be high enough to contribute to the observed toxicity.

Phycoremediation of municipal wastewater: Removal of nutrients and contaminants of emerging concern

High-rate algal ponds (HRAP) are an alternative to conventional wastewater treatment that could contribute to the circular economy by valorising reclaimed water and algal biomass. This short communication presents the removal of nutrients and contaminants of emerging concern (CEC) in a pilot-scale HRAP treating primary municipal wastewater. Average removal of total organic carbon, total nitrogen, NH4-N, total phosphorus and PO4-P, was 67%, 76%, 87%, 41% and 46%, respectively. In addition, 12 CECs were detected in the influent and five in the effluent. Removals were as follows: naproxen 60%, ibuprofen 51%, methylparaben 92%, 2,4-dihydroxybenzophenone 76% and oxybenzone 80%, and are comparable with literature data for conventional wastewater treatment and other HRAPs. In conclusion, studies of nature-based solutions such as HRAPs show encouraging results but need further research to understand the risks and requirements of safe wastewater and biomass reuse.

Table grapes irrigation with treated municipal wastewater in a Mediterranean environment

AbstractThis study investigated the effect of different water quality regimes [Freshwater (FW), treated wastewater (TW) and alternating FW and TW (FW‐TW)] on drip‐irrigated table grape yield, quality and microbial contamination. Water and soil samples were analysed. In addition, grape samples were harvested for quantitative and qualitative evaluation. The results showed that the plants irrigated with TW and those irrigated with alternating FW and TW gave 19.57 and 14.95% higher marketable yield, respectively, than plants irrigated with FW. Total soluble sugars, total titratable acidity and sweetness ranged, respectively, between 18.43–20.13, 0.69–0.81% and 21.52–29.19, and were within the desirable levels for table grape harvest. In addition, there was no significant difference in terms of total phenols and mineral composition of berries, leaves, peduncle and pedicels. Finally, table grapes did not present any bacterial contamination which confirm the importance of the adopted irrigation regime for a safe wastewater reuse in agriculture.