mL Of Wastewater Research Articles

Definition of a concentration and RNA extraction protocol for optimal whole genome sequencing of SARS-CoV-2 in wastewater (ANRS0160)

Monitoring the presence of RNA from emerging pathogenic viruses, such as SARS-CoV-2, in wastewater (WW) samples requires suitable methods to ensure an effective response. Genome sequencing of WW is one of the crucial methods, but it requires high-quality RNA in sufficient quantities, especially for monitoring emerging variants. Consequently, methods for viral concentration and RNA extraction from WW samples have to be optimized before sequencing. The purpose of this study was to achieve high coverage (≥ 90 %) and sequencing depth (at least ≥200×) even for low initial RNA concentrations (< 105 genome copies (GC)/L) in WW. A further objective was to determine the range of SARS-CoV-2 RNA concentrations that allow high-quality sequencing, and the optimal sample volume for analysis. Ultrafiltration (UF) methods were used to concentrate viral particles from large influent samples (up to 500 mL). An RNA extraction protocol using silica beads, neutral phenol-chloroform treatment, and a PCR inhibitor removal kit was chosen for its effectiveness in extracting RNA and eliminating PCR inhibitors, as well as its adaptability for use with large influent samples. Recovery rates ranged from 24 % to 63 % (N = 17) for SARS-CoV-2 naturally present in WW samples. 200 mL WW samples can be enough for UF concentration, as they showed high quality sequencing analyses with between 5 × 104 GC/L and 6 × 103 GC/L. Below 6 × 103 GC/L, high-quality sequencing was also achieved for ∼40 % of the samples using 500 mL of WW. Sequencing analysis for variant detection was performed on 200 mL WW samples with coverage of >95 % and sequencing depth of >1000×. Analyses revealed the predominance of variant EG.5, known as Eris (66 %–100 %). The use of UF methods in combination with a suitable RNA extraction protocol appear promising for sequencing enveloped viruses in WW in a context of viral emergence.

Degradation of methyl orange dye using Fe3O4/GO photocatalyst with iron derived from coastal Glagah Kulon Progo ore

Water pollution by dyes is still a serious problem that needs to be solved. This study offers a solution to degrade methyl orange dye using a photocatalyst material, namely Fe3O4/GO nanocomposite. Magnetite (Fe3O4) was synthesized from iron sand from Glagah Kulon Progo beach, using the coprecipitation method. Graphene oxide (GO) was synthesized by Hummers’ method, while the manufacture of the Fe3O4/GO nanocomposite was done by sonication method. The resulting magnetite, graphene oxide and nanocomposite were then characterized by XRD, UV–Vis and SEM-EDX. The effect of nanocomposite mass variation and irradiation time on the percentage degradation of the synthetic dye methyl orange (MO) in wastewater was investigated. The results of UV-Vis’s characterization showed that the best results were obtained when MO dye was degraded using 0.175 g nanocomposite in 40 mL of wastewater containing 10 ppm MO. The degradation of MO dye reached 99.05% under UV light irradiation for 240 minutes. Then investigated reuse of the nanocomposite was evaluated for three cycles, with the results showing an average efficiency decrease of 5.30%. This research contributes to the development of sustainable and effective photocatalytic materials for the treatment of dye-polluted water, especially MO.

Micro-solid phase extraction of pharmaceuticals and illicit drugs from wastewaters using monolith-coated syringe filters

In this study, a porous monolith of poly(methacrylic acid-co-ethylene glycol dimethacrylate) has been prepared on the nylon membrane of a commercial syringe filters (13 mm, 0.22 µm) for the micro solid-phase extraction (µSPE) of pharmaceutical and illicit drugs from wastewater samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination. Polymer synthesis conditions were designed and adjusted to provide robust devices with reduced costs and ease of use. The performance of the developed devices was assessed by investigating the most appropriate µSPE conditions. The features of the proposed device allow for the extraction of sample volumes up to 25 mL of wastewater and the use of minimal amounts of organic solvents (200 µL of 0.1 % formic acid in methanol) in the desorption step, providing a 125 enrichment factor. Sample extracts were measured by LC-MS/MS, providing limits of detection from 2 to 22 ng/L, recoveries from 84 to 120 %, and relative standard deviations lower than 16 %. The proposed approach has demonstrated to be suitable for the easy and simple extraction of forty-two psychoactive substances from wastewater samples with a reduced solvent consumption, low cost, minimal environmental impact, and high enrichment capacity. The method greenness and practicality has been evaluated using AGREEprep, complexGAPI, and BAGI tools, demonstrating an adequate green character and practicality of the proposed methodology.

Biomass polyamine-functionalized nanocellulose-loaded covalent organic framework to construct composite aerogels for highly efficient removal of Cr (VI) and methyl orange

Heavy metal ions and organic dyes cause ecological pollution, which is a problem that needs to be solved urgently. In this study, a novel biomass polyamine-functionalized nanocellulose loaded-covalent organic framework (COF) successfully constructed a hybrid aerogel (TDB). Due to the synergistic effect of biomass polyamines and COF, a vast number of active sites are present on the surface of TDB aerogel. This made the TDB aerogel have the largest adsorption capacity (470.67 mg/g, 488.22 mg/g) and the highest removal efficiency (98.49 %, 99.51 %) for Cr (VI) or MO (methyl orange). In the binary pollutant system, TDB aerogel also showed excellent removal efficiency for Cr (VI) and MO (91.29 %, 82.84 %). The adsorption process and adsorption mechanism of TDB aerogel were analyzed by adsorption kinetics, adsorption isotherms, thermodynamics, FTIR, and XPS. Its crystalline structure also didn't change. Fixed-bed column adsorption experiments showed that TDB aerogel could effectively purify 4510 mL of wastewater that contained Cr (VI) or 4681 mL of wastewater that contained MO. Therefore, TDB aerogel can be considered a promising adsorbent for the treatment of heavy metal ions and organic dyes in wastewater.

Indication of Phages and Their Role in the Regulation of the Purification Process at the Govsany Aeration Station in Baku

Due to the epidemic situation and the emergence of enteroviral diseases, we set ourselves the task of conducting comprehensive virological and bacteriological studies of the wastewater, its sludge and contaminated soil from the Govsany aeration station. The fact of constant detection of enteroviruses in samples of wastewater and soil in combination with bacteriophages is considered by us as a possibility of detection of bacteriophages at WWTP sites. The 26 wastewater samples contain enteroviruses at various stages of treatment, 18 of which were characterised by high levels of faecal contamination (thermoletarian coliforms), C. perfringens and Enterococcus faecalis. In samples with high contamination (TCB up to 106 per 100 ml of wastewater), which are potentially dangerous in terms of the content of infectious disease pathogens, both bacterial and viral, the number of coliphages was below the norm. Consequently, coliphages cannot be used as a sanitary indicator of microorganisms of viral contamination. Intestinal phages are common where humans and animals live and therefore intestinal bacteria are present. Coliphages (bacteriophages) can be formed from lysogenic enterobacteria during the process of stepwise wastewater treatment at the Govsany WWTP.

Chromium adsorption capacity from tannery wastewater on thermally activated adsorbent derived from kitchen waste biomass

Environmental sustainability has gained greater acceptance as an approach to achieving the objective of a secure ecosystem with a reliable management system. The best strategy for maintaining a healthy ecosystem is waste management. In this present study, chromium (Cr) adsorption capacity from real tannery wastewater on thermally activated adsorbent, equipped from Cucurbita moschata (pumpkin) peel is described. The adsorbent features were investigated by implementing Fourier transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and pHpzc (point of zero charges) analysis. The Cr adsorption was identified by EDX analysis. SEM images were analyzed to record surface morphological modifications. The adsorbent has a pHpzc of 8.7. The thermally activated adsorbent is used to treat the wastewater, in a batch experiment with varying parameters including contact time, adsorbent dose, and pH. Under optimal circumstances, 50 mL of wastewater was mixed with 2.5 g of adsorbent, agitated for 10 min, allowed to settle, and then the Cr concentration was evaluated. The Cr level in untreated effluent and in filtrate was 3178.6 mg/L, and 12.1 mg/L, respectively. The capability of Cr adsorption and Cr removal efficiency was 3164.46 mg/g and 99.32%, correspondingly, at a pH of 7.2. The biochemical oxygen demand (BOD), chloride (Cl-), and chemical oxygen demand (COD) showed a decreasing percentage of 96.58%, 55.62%, and 95.01%. The Cr adsorption fitting for pumpkin peel adsorbent follows the Pseudo second-order (PSO) kinetic and Freundlich isotherm model. Thus, this investigation established the efficiency of using pumpkin peel as an adsorbent for Cr tanning effluent treatment.

Method for Extraction and Evaluation of Heliocarpus popayanensis and Triumfetta bogotensis as Natural Coagulants for the Treatment of Wastewater.

This research evaluates extracts from the bark of Heliocarpus popayanensis and Triumfetta bogotensis as coagulating agents for removing turbidity in domestic wastewater, considering the coagulant dosage and pH of the wastewater. ANOVA was conducted to assess differences between the coagulants, dosages, and pH, with three pH levels (5, 8, and 9) and six dosages (7, 9, 11, 13, 15, and 17 mL per 1000 mL of wastewater) at a significance level of α = 0.05, and both the p-value and effect size were evaluated. This study found that the mucilaginous compound from the bark of Triumfetta bogotensis performed better in reducing turbidity levels, with an average reduction of 30.2 NTU (Nephelometric Turbidity Unit) (CI [25.9 NTU; 34.5 NTU], α = 0.05) at a pH of 5, and an average initial NTU of 102.2. This represents an average reduction of 70.45%. The dosage factor did not show significant effects on turbidity reduction, which opens the possibility for further study to determine the optimal dosage of the best coagulant.

Comparison of concentration and extraction workflows for qPCR quantification of intI1 and vanA in untreated wastewater

Quantitative polymerase chain reaction (qPCR) measurement of antibiotic resistance genes (ARGs) in untreated municipal wastewater may prove useful in combating the antimicrobial resistance crisis. However, harmonizing and optimizing qPCR-based workflows is essential to facilitate comparisons across studies, and includes achieving highly-effective ARG capture through efficient concentration and extraction procedures. In the current study, combinations of sample volume, membrane types and DNA extraction kits within filtration and centrifugation-based workflows were used to quantify 16S ribosomal RNA (16S rRNA), class 1 integron-integrase gene (intI1) and an ARG encoding resistance to vancomycin (vanA) in untreated wastewater sampled from three wastewater treatment plants (WWTPs). Highly abundant 16S rRNA and intI1 were detected in 100 % of samples from all three WWTPs using both 2 and 20 mL sample volumes, while lower prevalence vanA was only detected when using the 20 mL volume. When filtering 2 mL of wastewater, workflows with 0.20-/0.40-μm polycarbonate (PC) membranes generally yielded greater concentrations of the three targets than workflows with 0.22-/0.45-μm mixed cellulose ester (MCE) membranes. The improved performance was diminished when the sample volume was increased to 20 mL. Consistently greater concentrations of 16S rRNA, intI1 and vanA were yielded by filtration-based workflows using PC membranes combined with a DNeasy PowerWater (DPW) Kit, regardless of the sample volume used, and centrifugation-based workflows with DNeasy Blood & Tissue Kit for 2-mL wastewater extractions. Within the filtration-based workflows, the DPW kit yielded more detection and quantifiable results for less abundant vanA than the DNeasy PowerSoil Pro Kit and FastDNA™ SPIN Kit for Soil. These findings indicate that the performance of qPCR-based workflows for surveillance of ARGs in wastewater varies across targets, sample volumes, concentration methods and extraction kits. Workflows must be carefully considered and validated considering the target ARGs to be monitored.

Quantification and Differentiation of SARS-CoV-2 Variants in Wastewater for Surveillance.

Wastewater surveillance plays an important role in the monitoring of infections of SARS-CoV-2 at the community level. We report here the determination of SARS-CoV-2 and differentiation of its variants of concern in 294 wastewater samples collected from two major Canadian cities from May 2021 to March 2023. The overall method of analysis involved extraction of the virus and viral components using electronegative membranes, in situ stabilization and concentration of the viral RNA onto magnetic beads, and direct analysis of the viral RNA on the magnetic beads. Multiplex reverse transcription quantitative polymerase chain reaction (RT-qPCR) assays, targeting specific and naturally selected mutations in SARS-CoV-2, enabled detection and differentiation of the Alpha, Beta, Gamma, Delta, and Omicron variants. An Omicron triplex RT-qPCR assay targeting three mutations, HV 69-70 deletion, K417N, and L452R, was able to detect and differentiate the Omicron BA.1/BA.3, BA.2/XBB, and BA.4/5. This assay had efficiencies of 90-104% for all three mutation targets and a limit of detection of 28 RNA copies per reaction. Analyses of 294 wastewater samples collected over a two-year span showed the concentrations and trends of Alpha, Beta, Gamma, Delta, and Omicron variants as they emerge in two major Canadian cities participating in the wastewater surveillance program. The trends of specific variants were consistent with clinical reports for the same period. At the beginning of each wave, the corresponding variants were detectable in wastewater. For example, RNA concentrations of the BA.2 variant were as high as 104 copies per 100 mL of wastewater collected in January 2022, when approximately only 50-60 clinical cases of BA.2 infection were reported in Canada. These results show that the strategy and highly sensitive assays for the variants of concern in wastewater are potentially useful for the detection of newly emerging SARS-CoV-2 variants and other viruses for future community biomonitoring.

Solar photocatalytic hydrogen production from pulp and paper wastewater

The solar photocatalytic degradation of pulp and paper mill wastewater has been reported by several scientists. However, this is the first time we are reporting for solar photocatalytic hydrogen production from pulp and paper mill wastewater and simultaneous degradation of pollutants. In this work, CuO based photocatalysts and novel square type photocatalytic reactor of 5 L capacity were used. The result shows that the prepared photocatalysts are solar active, efficient in hydrogen recovery and pollutant degradation from the pulp and paper wastewater. The effects of catalyst loading, sacrificial agent, pollutant removal efficiency and stability check were investigated. At 0.25 g/L of CuO/Fe2O3, 0.2 M of sacrificial agent (Na2SO32−) and hydrogen yield of 1000 mL from 1000 mL of wastewater was achieved. The removal efficiency of TSS, TDS, BOD, COD, turbidity and TOC are around 70, 50, 60, 65, 70 and 45% respectively. Reusability study revealed that CuO/Fe2O3 was chemically stable and could be reused successively (five cycles) without significant changes in its photoactivity and intrinsic properties.

Fluidized Immobilized Carbon Catalytic Oxidation Reactor for Treating Domestic Wastewater.

Treating wastewater and reusing it have become normal in the present era since the scarcity of fresh water prevails in many parts of the world. There are numerous techniques for treating domestic wastewater, and many have been explored to advance the ones already in use. This study is taken up to explore the new technology called fluidized immobilized carbon catalytic oxidation (FICCO). Usually, both organic and inorganic materials are present in residential wastewater. In this study, catalyst-activated carbon produced from rice husk is added to a FICCO reactor to test the effectiveness of decreasing organic contaminants in wastewater. Six FICCO models were fabricated in this research study, and tests were conducted. The effectiveness of COD and BOD removal was investigated using six FICCO models with activated carbon made from rice husk as a catalyst and presented in this paper. The FICCO reactor was also used to treat organic contaminants such as surfactants, starch, oil, and protein with rice husk as activated carbon as a catalyst. Organic pollutants used the FICCO reactor; COD removal varied from 75.6% to 92.4%, BOD removal ranged from 74.9% to 89.5% at the optimum contact time, and catalyst rice husk-activated carbon application. The optimum catalyst dosage was 12 g per 620 ml of wastewater, which is the capacity of each reactor and a substantial reduction in sludge.

Oxygen Vacancy-Mediated Activates Oxygen to Produce Reactive Oxygen Species (ROS) on Ce-Modified Activated Clay for Degradation of Organic Compounds without Hydrogen Peroxide in Strong Acid.

The treatment of acid wastewater to remove organic matter in acid wastewater and recycle valuable resources has great significance. However, the classical advanced oxidation process (AOPs), such as the Fenton reaction, encountered a bottleneck under the conditions of strong acid. Herein, making use of the oxidation properties of CeAY (CeO2@acid clay), we built an AOPs reaction system without H2O2 under a strong acid condition that can realize the transformation of organic matter in industrial wastewater. The X-ray photoelectron spectroscopy (XPS) proved that the CeAY based on Ce3+ as an active center has abundant oxygen vacancies, which can catalyze O2 to produce reactive oxygen species (ROS). Based on the electron spin-resonance spectroscopy spectrum and radical trapping experiments, the production of •O2- and •OH can be determined, which are the essential factors of the degradation of organic compounds. In the system of pH = 1.0, when 1 mg CeAY is added to 10 mL of wastewater, the degradation efficiency of an aniline solution with a 5 mg/L effluent concentration is 100%, and that of a benzoic acid solution with a 100 mg/L effluent concentration is 50% after 10 min of reaction. This work may provide novel insights into the removal of organic pollutants in a strong acid water matrix.

Synthesis, Characterization, and Dye Removal Applications of Graphene Oxide-Gold Nanocomposite

Here, we report the facile synthesis of graphene oxide/gold nanocomposite, and dye removal ability as an adsorbent was studied. Sodium citrate as a reducing agent was used to reduce Au (III) ions to the formation of gold nanoparticles on the surface of graphene oxide sheets that were prepared by Hummers’ method. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) was used to specify nanocomposite synthesis. Adsorption dosage and contact time were investigated and explained as influencing parameters in removing methylene blue and methyl orange. In optimum conditions, the amount of adsorbent 30 mg and contact time 15 min for methylene blue and the amount of adsorbent 30 mg and contact time 25 min for methyl orange were quantitatively removed from 10 mL of wastewater. The pseudo-second-order model explained the kinetic data. Since graphene oxide/gold nanocomposite could be reused reasonably and had adsorptive properties, it tends to be produced as a modest and elective adsorbent to treat wastewater.

An efficient method to enhance recovery and detection of SARS-CoV-2 RNA in wastewater

Wastewater surveillance (WS) of SARS-CoV-2 currently requires multiple steps and suffers low recoveries and poor sensitivity. Here, we report an improved analytical method with high sensitivity and recovery to quantify SARS-CoV-2 RNA in wastewater. To improve the recovery, we concentrated SARS-CoV-2 viral particles and RNA from both the solid and aqueous phases of wastewater using an electronegative membrane (EM). The captured viral particles and RNA on the EM were incubated in our newly developed viral inactivation and RNA preservation (VIP) buffer. Subsequently, the RNA was concentrated on magnetic beads and inhibitors removed by washing. Without eluting, the RNA on the magnetic beads was directly detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Analysis of SARS-CoV-2 pseudovirus (SARS-CoV-2 RNA in a noninfectious viral coat) spiked to wastewater samples showed an improved recovery of 80%. Analysis of 120 wastewater samples collected twice weekly between May 2021 and February 2022 from two wastewater treatment plants showed 100% positive detection, which agreed with the results independently obtained by a provincial public health laboratory. The concentrations of SARS-CoV-2 RNA in these wastewater samples ranged from 2.4×102 to 2.9×106 copies per 100 mL of wastewater. Our method's capability of detecting trace and diverse concentrations of SARS-CoV-2 in complex wastewater samples is attributed to the enhanced recovery of SARS-CoV-2 RNA and efficient removal of PCR inhibitors. The improved method for the recovery and detection of viral RNA in wastewater is important for wastewater surveillance, complementing clinical diagnostic tests for public health protection.

Evaluation of environmental microorganism’s anti-bioresistance from sewage collectors from Abobo to Vridi, in the District of Abidjan, Côte d’Ivoire

Objectives: The spread of bacterial resistance to antibiotics in the environment remains a major public health problem. Health centers, effluent treatment plants, livestock farms, households and collection centers are considered platforms for the transit and exchange of multi-resistant bacteria. Methods: This study was conducted to evaluate the level of antibiotic resistance of microorganisms in the environment. It consisted in collecting samples of wastewater from evacuation and sanitation channels in the city of Abidjan. A total of 99 samples of 2970 mL of wastewater were collected and standard microbiology methods were implemented. Results: At the end of the analysis, 215 coliforms of faecal or non-faecal, aquatic and telluric origin were identified. These microorganisms showed 55.81% resistance to β-lactams, mainly to amoxicillin, 7.67% to aminoglycosides, 6.05% to tetracycline and 3.49% to quinolones. Conclusion: Environmental bacterial strains are more and more resistant to the usual antibiotics.

Effectiveness of Sludge Microbial Consortia in the Bioremediation of Detergent-Containing Launderette Wastes

This project investigated the potential of microbial consortia obtained from several sources to reduce or eliminate detergent concentration in the wastes of launderette businesses found in the capital city of Bali. Before being used as active starters, the consortium of microbiota contained in the 3 waste sources was enriched in a medium containing (g/l); 1 glucose, 0.05 K2HPO4, 0.05 KH2PO4, 0.05 (NH4)2[Fe(SO4)2].6H2O, 0.01 MgSO4, 0.01 yeast extract, 1800 mL distilled water, and 200 mL of wastewater of launderette industries. An important parameter used to indicate microbial growth was the level of the volatile solid substrate (VSS) in the enrichment medium. The microbial culture that showed the highest VSS only was further investigated in the main experiments by observing its effectiveness in reducing detergent linear alkyl-benzenesulfonates (LAS) and the chemical oxygen demand (COD) of launderette wastes. In this project, microbial consortia developed from detergent-containing launderette wastes were the most active starter to decrease the COD and LAS detergent content following 7 days of exposure. This starter (microbial consortia developed from this launderette waste) showed the highest value of VSS when compared to those collected from other sources, and this was reached on day 4. In the main experiment, 85.5% and 91.9% reduction of LAS and the COD of the wastes, respectively, were observed following exposure of the launderette waste with this culture starter. This indicated that these microbial consortia have the possibility to be developed as a potential starter in larger scales of detergent bioremediation.

Effect of high-voltage spark discharges on reduction of the concentration of total bacterial count in wastewater

The limited supply of fresh water on the planet stimulates the reuse of wastewater in various areas. It is proposed to use disinfected wastewater for irrigation in agriculture. The possibility of reducing the total bacterial count in wastewater by high-voltage spark discharges using a developed experimental setup has been investigated. The total bacterial count was measured by the rapid method using a luminometric mini-laboratory EnSURE Touch and a standard method for counting bacteria, capable of forming colony-forming units on nutrient agar. Wastewater from the Zhulebinsky storm collector with an initial concentration of 1012 CFU ml−1 with a volume of 103 ml is disinfected up to the norm 6 log in 120 s with capacitance 0.1 μF and in 180 s with capacitance 0.05 μF. Wastewater from the Kuryanovsky storm channel with an initial concentration of 109 CFU ml−1 with a volume of 103 ml is disinfected up to the norm 6 log in 100 s with capacitance 0.1 μF and in 160 s with capacitance 0.05 μF. To reduce the concentration of total bacterial count by 1 log, the minimum duration of disinfection of 103 ml of wastewater it took about 30 s at a discharge energy of 5 J ml−1. The advantages of bacterial inactivation in wastewater by high-voltage spark discharges were revealed, such as low operating voltage of 10 kV, high energy efficiency of 600 J l−1 and capacity 30 l h−1, increased service life and operational reliability, portability and environmental friendliness.

Comparison of Detecting and Quantitating SARS-CoV-2 in Wastewater Using Moderate-Speed Centrifuged Solids versus an Ultrafiltration Method

Mounting evidence suggests that solids are a reliable matrix for SARS-CoV-2 detection in wastewater, yet studies comparing solids-based methods and common concentration methods using the liquid fraction remain limited. In this study, we developed and optimized a method for SARS-CoV-2 detection in wastewater using moderate-speed centrifuged solids and evaluated it against an ultrafiltration reference method. SARS-CoV-2 was quantified in samples from 12 wastewater treatment plants from Alberta, Canada, using RT-qPCR targeting the N2 and E genes. PCR inhibition was examined by spiking salmon DNA. The effects of using different amounts of solids, adjusting the sample pH to 9.6–10, and modifying the elution volume at the final step of RNA extraction were evaluated. SARS-CoV-2 detection rate in solids from 20 mL of wastewater showed no statistically significant difference compared to the ultrafiltration method (97/139 versus 90/139, p = 0.26, McNemar’s mid-p test). The optimized wastewater solids-based method had a significantly lower rate of samples with PCR inhibition versus ultrafiltration (3% versus 9.5%, p = 0.014, Chi-square test). Our optimized moderate-speed centrifuged solids-based method had similar sensitivity when compared to the ultrafiltration reference method but had the added advantages of lower costs, fewer processing steps, and a shorter turnaround time.

Cytotoxicity and Genotoxicity evaluation of municipal wastewater discharged into the head of Blue Nile River using the Allium Cepa test

Municipal wastewaters may contain a variety of genotoxic pollutants that are discharged into rivers and causing deterioration of the environment in downstream reaches. The present study evaluates the hazardous effects of untreated municipal wastewater discharge from the city of Bahir Dar to the head of the Blue Nile River. This was done by collecting wastewater samples from the upper, middle and lower sites of the stream and characterizing its physicochemical qualities. In all cases, tap water was taken as a control and the wastewater qualities were significantly varied among the studied sites. The highest values of EC, TDS, COD, etc. were found at the middle site. Further, the wastewater showed significant differences in terms of cytotoxicity (in root number, root length, mitotic index) and genotoxicity (chromosomal aberrations) in Allium cepa tests after three days of growth at (0, 25, 50, 75 and 100 ml) dilution values of wastewater. The cytotoxic effects of wastewater were significantly varied at different treatment values and collection sites of the stream. The mitotic index was reduced to 1.80 ± 0.03 from 12.59 ± 0.28, 1.26 ± 0.02 from 12.78 ± 0.38 and 2.05 ± 0.04 from 12.81 ± 0.19 at 100 ml of wastewater compared to the control at the upper, middle and lower sites respectively. The EC50 values for root growth inhibition followed the order middle < upper < lower, indicating greater toxicity of a middle site. Moreover, the wastewater incurred significantly more genotoxic effects on root tip cells in comparison to the control and also varied among sampling sites. Most recorded abnormalities were anaphase bridges, chromosome fragments, c-mitosis, binucleated and micronucleated cells. Thus untreated wastewater discharges have a potential threat to the water ecosystem and public health as the river is used for different purposes by downstream societies.

The effectivity of red algae as biosorben to reduce the effect of laboratory wastewater

The research on laboratory wastewater treatment using Eucheuma cottoni as biosorbent was carried out to find the right composition of wastewater and algae that is effective in reducing the pollutant contained in the laboratory wastewater. The dosages of biosorbent were varied with 100 gr, 200 gr, and 300 gr were added into 1000 ml of wastewater mixed with 1000 ml of sea water. Chemical parameters such as pH, COD and NH3 and physical parameters such as odor, color, turbidity were analyzed and in accordance with contact time parameters of H1 (1 hour), H2 (12 hours) and H3 (24 hours). The percentage of pollutant reduction in wastewater was calculated by comparing the value before treatment with the value after treatment to get the right composition of the biosorbent to get the highest reduction percentage. The percentage of pollution reduction in the value of each parameter, showed that the third treatment with 300 gr of biosorbent was the most effective condition in reducing the pollutant contained in laboratory wastewater with the final outcomes were pH 6.67 COD 74.67 mg / L, NH3 0.731 mg / L, scale 1 color 40 PtCo and turbidity 37.6 NTU. The results are in accordance with Wastewater Quality standards Permen LH No. 5 of 2014.