This research encompassed an 8-month investigation to evaluate the biological treatment of complex landfill leachates. The primary objectives were the removal of organic and nitrogen compounds, as well as the mitigation of H2S and VOC emissions. Biological treatment was conducted within a sequencing batch reactor (SBR), incorporating aerobic, anaerobic, and anoxic stages. The results indicate that biological treatment is indeed effective in eliminating biodegradable organic matter, with an average removal rate of 84.5% for BOD5, 42.7% for COD, and 40.9% for TOC. Nonetheless, it is imperative to integrate supplementary processes to enhance organic removal. It is worth noting that biological nitrification proved inadequate for sufficiently reducing elevated ammonia concentrations, achieving only a 23.2% reduction. In controlled laboratory conditions, the utilization of chemical precipitation, employing either MgO+H3PO4 or MgCl2.6 H2O+Na2HPO4.7 H2O in an equimolar ratio of Mg:NH4:PO4, exhibited substantial ammonia removal rates of 76.8 ± 6.4% and 80.7 ± 4.5%, respectively. Additionally, the incorporation of an anoxic stage in reactor operation demonstrated its effectiveness in achieving proficient denitrification, with an 80% removal rate for nitrates present in the raw leachates. These findings underscore the potential for optimizing the efficiency of biological leachate treatment processes through strategic modifications and the integration of additional treatment steps.

Ultrafiltration (UF) is increasingly used as pretreatment for reverse osmosis (RO) desalination, as an alternative to granular filtration. To ensure a sustainable and cost-effective operation of UF, key operational parameters must be optimized. In the present study we used a pilot UF system to optimize filtration flux, length of filtration cycle, coagulant dosing, and membrane cleaning procedure. Filtration flux of 82 LMH resulted in reversible fouling, which could be completely removed during chemically enhanced backwash, and did not affect filtration performance. Increasing the flux to 85 LMH on the other hand, resulted in the formation of irreversible fouling, which rapidly deteriorated UF operation. Filtration time of 35 min between backwashes did not affect filtration, whereas, at longer filtration time of 45 min, (hydraulically) irreversible fouling was formed. Addition of Ferric chloride coagulation prior to UF (up to 0.6 mg/L-Fe) improved the removal of reversible fouling during backwash (BW), through the formation of pinflocs. In parallel, high ferric chloride concentrations generated ferric based irreversible fouling, which could only be removed by chemical cleaning. Finally, the study proposes a unique analysis of the trans membrane pressure (TMP) curve shape, for the optimization of coagulation and hydraulic cleaning during UF.

The COVID-19 pandemic created a global crisis impacting not only healthcare systems, but also economics and society. Therefore, it is important to find novel methods for monitoring disease activity. Recent data have indicated that fecal shedding of SARS-CoV-2 is common, and that viral RNA can be detected in wastewater. This suggests that wastewater monitoring is a potentially efficient tool for both epidemiological surveillance, and early warning for SARS-CoV-2 circulation at the population level. In this study we sampled an urban wastewater infrastructure in the city of Ashkelon (̴ 150,000 population), Israel, during the end of the first COVID-19 wave in May 2020 when the number of infections seemed to be waning. We were able to show varying presence of SARS-CoV-2 RNA in wastewater from several locations in the city during two sampling periods, before the resurgence was clinically apparent. This was expressed with a new index, Normalized Viral Load (NVL) which can be used in different area scales to define levels of virus activity such as red (high) or green (no), and to follow morbidity in the population at the tested area. The rise in viral load between the two sampling periods (one week apart) indicated an increase in morbidity that was evident two weeks to a month later in the population. Thus, this methodology may provide an early indication for SARS-CoV-2 infection outbreak in a population before an outbreak is clinically apparent.

Colloidal particles removal from water is a challenge in surface water treatment. Previously, we suggested an original technique for colloidal particles separation from water based on physical flow manipulation by an oscillating device. Laboratory experiments and 2D numerical simulation indicated that this technology enhances colloidal particles grouping and enables their rapid, simultaneous aggregation and sedimentation. The 2D model used in that study was unable to fully elucidate the grouping mechanism, settling pattern, or particle trajectories. Here, we extended the numerical simulation from 2D to 3D and examined the system's distinctive flow field. The flow field was solved with computational fluid dynamics (CFD) simulations in the commercial ANSYS Fluent code and validated by dye injection experiments. The sedimentation patterns could nicely be explained by the computational results. This explanation was strengthened by two-dimensional population balance model simulations, which showed that particles aggregated in two zones trailing the paddle edges. Additionally, the results indicate significantly higher TKE values and faster upward vertical velocities at the higher oscillating frequency, which explains the different sedimentation patterns and removal efficiencies generated by the different oscillation frequencies. The use of 3D numerical simulations will help to better understand and further optimize this novel technology.

Water and soil contamination by industrial wastes is a global concern. Biological treatment of industrial wastewater using bioreactors allows the removal of organic matter and nutrients and enables either reuse or safe discharge. Wastewater bioremediation depends in part on the microbial communities present in the bioreactor. To ascertain which communities may play a role in the remediation process, the present study investigates the microbial community structure and diversity of microorganisms found in a full-scale membrane bioreactor (MBR) for industrial wastewater treatment. The study was carried out using high-throughput data observations following a failure (crash) of the MBR and during the extended recovery of the process. Results revealed a positive correlation between the MBR's ability to remove organic matter and its microbial community richness. The significant changes in relative microbial abundance between crash and recovery periods of the MBR revealed the important role of specific bacterial genera in wastewater treatment processes. A whole-genome metagenomics based comparison showed a clear difference in microbial makeup between two functional periods of MBR activity. The crash period was characterized by abundance in bacteria belonging to Achromobacter, Acinetobacter, Halomonas, Pseudomonas and an uncultured MBAE14. The recovery period on the other hand was characterized by Aquamicrobium and by Wenzhouxiangella marina. Our study also revealed some interesting functional pathways characterizing the microbial communities from the two periods of bioreactor function, such as Nitrate and Sulfate reduction pathways. These differences indicate the connection between the bacterial diversity of the MBR and its efficiency to remove TOC.

This paper presents a research study aimed at the development of a hybrid biofilter that can serve for two different applications. This is a unique approach due to the prolonged dry period in Israel covering 7-8 months of the year. The tactic suggested herein is to use the same system for stormwater harvesting/treatment during winter, and for bioremediation of nitrate-contaminated groundwater during summer. Crude cotton and Eucalyptus wood-chips served as alternative carbon sources for denitrification, and both proved to support efficient reduction of nitrate with minimal release of nitrite and organic matter. During the stage of stormwater treatment, two types of biofilter-columns (120 & 70 cm long) were tested, with a minimal saturation zone and no addition of organic carbon. Complete nitrification could be achieved, even under high instantaneous hydraulic loads for both column types. Vegetation on top of the biofilters contributed to improved removal of the nitrate formed, by plant assimilation.

Members and partners of the Sewage analyses CORe group Europe - (SCORE) measured five illicit drug residues in wastewater 2011-2017 (every year one week). The data set covers in total 143 wastewater treatment plants in 120 cities from 37 countries, which were monitored at least once.

AbstractBackground and aimsWastewater‐based epidemiology is an additional indicator of drug use that is gaining reliability to complement the current established panel of indicators. The aims of this study were to: (i) assess spatial and temporal trends of population‐normalized mass loads of benzoylecgonine, amphetamine, methamphetamine and 3,4‐methylenedioxymethamphetamine (MDMA) in raw wastewater over 7 years (2011–17); (ii) address overall drug use by estimating the average number of combined doses consumed per day in each city; and (iii) compare these with existing prevalence and seizure data.DesignAnalysis of daily raw wastewater composite samples collected over 1 week per year from 2011 to 2017.Setting and ParticipantsCatchment areas of 143 wastewater treatment plants in 120 cities in 37 countries.MeasurementsParent substances (amphetamine, methamphetamine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of Δ9‐tetrahydrocannabinol (11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol) were measured in wastewater using liquid chromatography–tandem mass spectrometry. Daily mass loads (mg/day) were normalized to catchment population (mg/1000 people/day) and converted to the number of combined doses consumed per day. Spatial differences were assessed world‐wide, and temporal trends were discerned at European level by comparing 2011–13 drug loads versus 2014–17 loads.FindingsBenzoylecgonine was the stimulant metabolite detected at higher loads in southern and western Europe, and amphetamine, MDMA and methamphetamine in East and North–Central Europe. In other continents, methamphetamine showed the highest levels in the United States and Australia and benzoylecgonine in South America. During the reporting period, benzoylecgonine loads increased in general across Europe, amphetamine and methamphetamine levels fluctuated and MDMA underwent an intermittent upsurge.ConclusionsThe analysis of wastewater to quantify drug loads provides near real‐time drug use estimates that globally correspond to prevalence and seizure data.

Hard water with salts of Ca and Mg may cause scaling, and is often softened. Water with toxic substances, e.g. heavy metals, is harmful, and is often treated with different filtering methods, nowadays often reverse osmosis (RO). There are more than 21,000 desalination plants around the world, providing more than 350 million people with drinking water, and there are more to come. RO-treated waters without pH-adjustment tend to be corrosive; causing elevated levels of metals released from especially pipes, e.g. Pb, Fe and Cu, but also lack minerals, causing decreased daily intake and loss of minerals from the body. Even pH-adjusted RO water has very low mineral content. Food boiled in such water also tends to lose minerals. There are indexes to be used as guides to choose a re-mineralization method after RO. However, methods used today don't take mineral levels in treated drinking water preferable for human consumption into account, as corrosion aspects are only considered. Treatment with dissolution of dolomitic-calcitic limestone (free from toxic elements) giving 30-80 mg/L Ca, 100-300 mg/L HCO3, 10-50 mg/L Mg and 25-100 mg/L SO4, with Ca/Mg 2-3:1 would be preferable for drinking water production.

One of the major challenge in water treatment is the removal of mineral colloids of sub-micron to micron size that, virtually unaffected by gravity, cannot be easily settled out of solution. To aid in the removal of these particles, the coagulation/flocculation process is typically used, which involves the addition of chemicals to neutralize the repulsive electrical forces of the colloids and then mixing to enhance particle aggregation and promote the formation of flocs. The current study proposes an innovative technique for colloid removal based on physical flow manipulation by an oscillating device whose action causes intermittent velocity gradients over time, space and direction. This unique manipulation causes the suspended particles to aggregate and rearrange in separate groups that are amenable to sedimentation. The proposed technique was tested under various operational conditions, including oscillation frequencies, alum doses and with/without rapid mixing. In addition, it was compared to the traditional coagulation/flocculation process in the treatment of similar suspensions. The results indicate that gentle oscillation can promote simultaneous flocculation and sedimentation in the same reactor over short periods of time. This technique, whose implementation can result in reductions to reactor sizes and process times, has a strong potential to improve conventional processes.

Colloid removal in water treatment plants is commonly done by a sequence of processes that includes coagulation, flocculation, sedimentation, and filtration. The current study presents an innovative technique, termed grouping, for the removal of these suspended particles based on physical flow manipulation, which causes the particles to aggregate. Previous results showed that gentle oscillation in a cylindrical container facilitates simultaneous flocculation and sedimentation in the same reactor over shorter periods of time than are possible using the conventional treatment approach. This finding may confer marked improvements on the processes used today by enabling the use of both smaller reactors and less energy. Based on the findings with the cylindrical vessel, here the grouping technique is further examined in a rectangular container and over a range of different initial turbidities. The results indicate that the removal efficiency is higher in the rectangular container under the different initial turbidities tested. In addition, the removal efficiency was shown to remain robust with the decreases in initial turbidity and alum concentrations that occur during treatment. The positive results of our previous study taken together with this finding hint at the strong potential of the grouping technique to improve common flocculation processes.

This study assessed the use of an integrated biophysical process incorporating the addition of powdered activated carbon (PAC) to a dual-sludge biological process, in order to improve the removal of problematic contaminants from complex herbicides production wastewater. The main focus was on the removal of nitrogen compounds, total organic carbon (TOC), and halogenated organics (AOX). The dual-sludge pilot setup comprised a conventional activated sludge (CAS) system followed by a membrane bioreactor (MBR) system. The dilution ratio of raw wastewater was gradually decreased (with groundwater) from 0.8 to 0 (no dilution), and PAC was added in the last phase of the study to maintain an equilibrium concentration of 2000 mg/L. PAC addition stimulated a high and steady removal (98%) of the ammoniacal nitrogen, conforming to the sea discharge limit of 5 mg/L. However, the effluent concentrations of total nitrogen, TOC, and AOX were still above the stringent discharge limits of 20, 100 and 0.5 mg/L respectively. Furthermore, it was shown that synergistic effect of various toxic organic compounds, rather than mineral salinity, was the major cause for the acute inhibitions of nitrification and AOX removal. The study showed that the proposed process can function as an efficient treatment system for the complex wastewater typically produced in the herbicide industry, however, it is recommended that complementary physico-chemical treatment steps be added to the treatment process.

This study is part of a comprehensive research aimed at the development and application of the “Water Sensitive Cities” idea in Israel. This is a sustainable concept, incorporating among others the harvesting, treatment, and reuse of storm-water. The use of engineered biofiltration systems for the harvesting and treatment of storm-water in Israel is complicated due to the prolonged dry climate period, spanning 7–8 months of the year. Therefore, the tactic suggested is to use a hybrid biofiltration system for both storm-water harvesting/polishing during winter, and for remediation of nitrate-contaminated groundwater during summer. This paper focuses on the summer design (denitrification) configuration. In preliminary experiments, it was found that crude cotton could serve as an effective carbon source for denitrification. Further results are reported herein regarding the design and operation of biofilter columns applied for the treatment of synthetic mixtures simulating nitrate-contaminated groundwater. The columns were composed of crude cotton wool and polyethylene beads, which prevented the effect of cotton compression. This application was shown to enable controlled removal of nitrate to low levels, while emitting very low concentrations of total organic carbon (TOC) and nitrite. It was also concluded that a biofilter requires judicious design and operation, since complete removal of nitrogen oxides might lead to the formation of undesired compounds such as sulfides due to the development of anaerobic conditions.

Biological wastewater treatment relies on the ability of bacterial populations to breakdown organic materials and nutrients into end products, and toxic ingredients into harmless substances. In addition to bacteria, bacteriophages (viruses that infect bacteria) are ubiquitous in many ecological systems including bioreactors for wastewater treatment. This leads to predator–prey dynamics between these populations, which should be taken into consideration when modelling and applying biological treatment processes. In this study, the predator–prey relationship between bacteria and phages isolated from a wastewater treatment bioreactor was investigated. Using microtiter plates, which served as multiple micro scale eco‐systems, shifts in the bacterial population were monitored using a microplate reader. Based on this set of data, a mathematical model incorporating phage‐bacteria interactions was developed and calibrated using Matlab; the calibration process was analyzed. The microplate reader was shown to serve as a useful tool for parameter calibration and basic modelling of phage–bacteria behaviour in bioreactors.

The research compares four types of different designs of membrane bioreactors: (1) with 295-mm draft tube and without plastic carriers; (2) plastic carriers and 295-mm draft tube; (3) plastic carriers and 235-mm draft tube with two meshes around the bottom and top of a draft tube; and (4) plastic carriers without a draft tube. The feed for the reactors was artificial wastewater made from domestic wastewater and chicken manure, and membrane test data were based on a hollow fiber membrane module under ambient desert conditions. Process operation type D is the optimal choice. Mathematical analysis using total ranking methods, multi-indicator decision-making, and Hasse diagram support this choice. Concerning analysis by the different tools, inconsistencies between the rankings are noticed. Partial order ranking, as a method without any pre-assumptions concerning the possible relation between the single parameters, proves to be an elegant ranking method.

Bacteriophages are viruses that infect bacteria, and consequently they have a major impact on the development of a microbial population. In this study, the genome of a novel broad host range bacteriophage, Aquamicrobium phage P14, isolated from a wastewater treatment plant, was analyzed. The Aquamicrobium phage P14 was found to infect members of different Proteobacteria classes (Alphaproteobacteria and Betaproteobacteria). This phage contains a 40,551 bp long genome and 60% of its genes had blastx hits. Furthermore, the bacteriophage was found to share more than 50% of its genes with several podoviruses and has the same gene order as other polyvalent bacteriophages. The results obtained in this study led to the conclusion that indeed general features of the genome of the Aquamicrobium phage P14 are shared with other broad host range bacteriophages, however further analysis of the genome is needed in order to identify the specific mechanisms which enable the bacteriophage to infect both Alphaproteobacteria and Betaproteobacteria.

Inhibition of sulfide production by sulfate‐reducing bacteria can be achieved by the use of chemical agents such as nitrite, molybdate, or copper. Herein, we tested the effect of these biocides and their combinations on the growth and production of H2S by Desulfovibrio vulgaris subsp. vulgaris. At pH 6.6, lower concentrations of biocides were required to inhibit H2S production in comparison to pH 7.8, as a consequence of higher production rates of bactericidal nitrous acid, or lower formation rates of thiomolybdate. A combination of 0.1 mM MoO42− and 0.25 mM NO2− at pH 7.8 was found to be synergistic, leading to an inhibition rate of 56% in H2S production and of 85% in D. vulgaris growth.