Electrocoagulation process to Chemical and Biological Oxygen Demand treatment from carwash grey water in Ahvaz megacity, Iran

Association of the efficiency of hemodialysis instruments in the removal of microbial and chemical pollutant

Dialysis water is vital because of various harmful contaminants for patients. The aim of this study was to assess the efficiency of hemodialysis instruments in the removal of microbial and chemical pollutant in educational hospitals affiliated to Ahvaz Jundishapur University of medical sciences, Iran during 2018-2019. This cross-sectional descriptive research studied the microbial and chemical water quality of hemodialysis instruments in Razi, Sina, and Golestan hospitals in Ahwaz, Iran. 72 samples of microbial parameters and 24 samples of chemical parameters were collected from water used in hemodialysis instruments, including microbial characteristics (the total coliform, fecal coliform and heterotrophic bacteria counts) and chemical characteristics (pH, turbidity, PO₄, Cl, Mg, So₄, Ca, NO₂, and EC) at Razi, Imam, and Golestan educational hospitals on all weekdays during 2018-2019. In this study, experiments were done according to the current standard methods, EPA from hemodialysis instruments. Finally, using SPSS18 software and descriptive statistics, the relationship between results at the removal of toxic, microbial, and chemical pollutants in different months and hospitals was investigated. this study showed that the average concentration of chemical characteristics during the warm season at Razi, Imam, and Golestan educational hospitals for pH, Turbidity, PO₄, Cl, Mg, So₄, Ca, NO₂, and EC were (6.867, 6.4475, 6.53); (2.985, 3.035, 1.226); (0.075, 0.245, 0.195); (38.5, 21.965, 144.87); (1.552, 1.657, 39.445); (8.6, 4.5, 21.5), (2.09, 3.187, 78.975); (0.0082, 0.038, 0.155), and (125.25, 70.35, 78.35), respectively during 2018. Also, during 2019, results showed that the average levels of amounts for pH, Turbidity, PO₄, Cl, Mg, So₄, Ca, NO₂, and EC in Razi, Imam, and Golestan educational hospitals were (7.077, 7.252, 6.435), (1.725, 0.595, 4.16), (0.0775, 0.0597, 0.0297), (52.33, 138.81, 20.92), (23.52, 18.227, 8.767), (35, 27.25, 4.05), (14.58, 28.152, 9.25), (0.0067, 0.0045, 0.0032), and (210.52, 121.62, 29.16), respectively. According to the results, hemodialysis instruments in Razi and Imam have a 90% efficiency in removing heterotrophic bacteria counts (HPC). Based on these findings, educational hospital hemodialysis equipment effluent in Ahvaz, Iran was mitted to Iran environmental standards for use in hemodialysis machines. The result showed that the removal percentage level of microbial and chemical pollutants by the hemodialysis process is comparatively suitable. It should be mentioned that in the proper operation and reconstruction, hemodialysis systems can have an increased rate of removal of microbial and chemical pollutants.

A Review of On-Site Carwash Wastewater Treatment

In recent years, people’s environmental awareness has increased. The high density of the urban population has caused a considerable increase in the demand for car washing services, which has created large quantities of car wash wastewater. The main pollutants in car wash wastewater are detergents, dirt, oil, and grease. Untreated wastewater released into rainwater sewer systems or other water bodies may pollute the water and generate excessive bubble foams, which negatively affects urban appearance. Car washes are divided into mechanical car washes and manual or self-service car washes. In general, car washes have a small operation and scale, occupy limited land, and cannot afford wastewater treatment costs. Therefore, most car washes are not equipped with wastewater treatment facilities. Consequently, the discharge of wastewater from car washes negatively affects the water quality in the surrounding environment and results in wasteful use of water resources. This study reviewed 68 research papers on the quality, treatment techniques, treatment costs, and treatment effectiveness of car wash wastewater to provide a reference for car wash operators to contribute to the preservation of water resources. We found that there is a higher chance of recycling car wash wastewater when combing two different techniques for car wash wastewater treatment.

Identification of micropollutants from graywater of different complexity and remediation using multilayered membranes

Graywater reuse is one of the important concepts in attaining water sustainability. A major challenge in this area is to realize various components present in graywater. The present study involves the identification of the chemical components of graywater collected from three different environments and to investigate the efficiency of removal of some of these chemical components using ultrafiltration membranes (polyelectrolyte multilayer (PEM) membranes). The chemical components were analyzed using liquid chromatography connected with quadrupole time-of-flight (UPLC-Q-ToF-MS). A number of micropollutants including surfactants and certain contaminants of emerging concern (CECs) were identified from these samples. Out of 16 compounds identified, 13 were surfactants and the remaining were caffeine, oxybenzone, and benzophenone. These surfactants are mostly the ingredients of various detergents. Low-pressure filtration studies of the collected samples were carried out utilizing chitosan/polyacrylic acid (CHI/PAA) multilayer membranes. A 5.5 bilayer membrane showed more than 95% rejection of the identified compounds in the selected samples and significant improvement in the water quality parameters. This demonstrates that the membrane used in this work is effective in the removal of various chemicals from graywater as well as enhancing the water quality.

Investigating the Effectiveness of Recycled Agricultural and Cement Manufacturing Waste Materials Used in Oil Sorption

This research investigates how sorbents made from recycled waste materials affect the properties of water used to remove residues flushed from oil tanks transported by rail. The mineral sorbent was added to water following the flushing process. Water temperatures were maintained at 21 °C and 70 °C for a contact period of 30 min. The experiments demonstrated that: when the sorbent is active, turbidity removal efficiency was about 64%; color removal efficiency of 56% was obtained; and total iron concentration removal was approximately 68%. The effect of the characteristics of the materials on the adsorption capacity was evaluated using the removed amount of oil per one gram of every sorbent. It was found that straw sorbent oil adsorption capacity was up to 33 mg/g, peat sorbent 37 mg/g, and mineral sorbent 1.83 mg/g. The following were also measured during the experiment: temperature, pH, chemical oxygen usage, total iron concentrations, suspended matter, and oil concentrations. The findings show that recycled sorbents obtained from waste materials are environmentally sustainable and can be reused to treat water that has been used to flush oil transported in rail tanks.

Environmental risks and toxicity of surfactants: overview of analysis, assessment, and remediation techniques

This work comprehensively reviewed the toxicity and risks of various surfactants and their degraded products in the environmental matrices, various analytical procedures, and remediation methods for these surfactants. The findings revealed that the elevated concentration of surfactants and their degraded products disrupt microbial dynamics and their important biogeochemical processes, hinder plant-surviving processes and their ecological niche, and retard the human organic and systemic functionalities. The enormous adverse effects of surfactants on health and the environment necessitate the need to develop, select, and advance the various analytical and assessment techniques to achieve effective identification and quantification of several surfactants in different environmental matrices. Considering the presence of surfactants in trace concentration and environmental matrices, excellent analysis can only be achieved with appropriate extraction, purification, and preconcentration. Despite these pre-treatment procedures, the chromatographic technique is the preferred analytical technique considering its advancement and shortcomings of other techniques. In the literature, the choice or selection of remediation techniques for surfactants depends largely on eco-friendliness, cost-implications, energy requirements, regeneration potential, and generated sludge composition and volume. Hence, the applications of foam fractionation, electrochemical advanced oxidation processes, thermophilic aerobic membranes reactors, and advanced adsorbents are impressive in the clean-up of the surfactants in the environment. This article presents a compendium of knowledge on environmental toxicity and risks, analytical techniques, and remediation methods of surfactants as a guide for policymakers and researchers.

A critical review of state-of-the-art electrocoagulation technique applied to COD-rich industrial wastewaters

Electrocoagulation (EC) is one of the emerging technologies in groundwater and wastewater treatment as it combines the benefits of coagulation, sedimentation, flotation, and electrochemical oxidation processes. Extensive research efforts implementing EC technology have been executed over the last decade to treat chemical oxygen demand (COD)-rich industrial wastewaters with the aim to protect freshwater streams (e.g., rivers, lakes) from pollution. A comprehensive review of the available recent literature utilizing EC to treat wastewater with high COD levels is presented. In addition, recommendations are provided for future studies to improve the EC technology and broaden its range of application. This review paper introduces some technologies which are often adopted for industrial wastewater treatment. Then, the EC process is compared with those techniques as a treatment for COD-rich wastewater. The EC process is considered as the most privileged technology by different research groups owing to its ability to deal with abundant volumes of wastewater. After, the application of EC as a single and combined treatment for COD-rich wastewaters is thoroughly reviewed. Finally, this review attempts to highlight the potentials and limitations of EC. Related to the EC process in batch operation mode, the best operational conditions are found at 10 V and 60 min of voltage and reaction time, respectively. These last values guarantee high COD removal efficiencies of > 90%. This review also concludes that considerably large operation costs of the EC process appears to be the serious drawback and renders it as an unfeasible approach for handling of COD rich wastewaters. In the end, this review has attempted to highlights the potential and limitation of EC and suggests that vast notably research in the field of continuous flow EC system is essential to introduce this technology as a convincing wastewater technology.

Greywater as a sustainable source for development of green roofs: Characteristics, treatment technologies, reuse, case studies and future developments

Municipal activities are one of the most important water users worldwide; thus, the treatment and reuse of greywater for non-potable purposes helps to reduce a remarkable amount of consumed water within urban communities. To achieve greywater reuse standards, and remove surfactants, micropollutants, organic matters, microorganisms and other pollutants various methods including physical, chemical and biological processes have been used. Treated greywater can be used on site for different purposes: carwash, toilet flushing, fire protection, green roofs, green walls, non-food irrigation etc. Among them, the use of greywater is very important in the expansion of the green roofs. Green roofs offer many benefits to urban areas such as decreasing air pollution, reducing building cooling needs, promoting mental health of habitants, noise reduction and aesthetics improvement. Therefore, this article provides an overview mainly from two aspects, the possibilities of greywater reuse by studying the characteristics and available options for greywater treatment and its benefits toward the developing green roofs.

Advanced Treatment of Real Grey Water by SBR Followed by Ultrafiltration—Performance and Fouling Behavior

Grey water has been identified as a potential source of water in a number of applications e.g., toilet flushing, laundering in first rinsing, floor cleaning, and irrigation. The major obstacle to the reuse of grey water relates to pathogens, nutrients, and organic matter found in grey water. Therefore, much effort has been put to treat grey water, in order to yield high-quality water deprived of bacteria and with an appropriate value in a wide range of quality parameters (Total Organic Carbon (TOC), nitrate, phosphate, ammonium, pH, and absorbance), similar to the values for tap water. The aim of this study was to treat the real grey water, and turn it into high-quality, safe water. For this purpose, the real grey water was treated by means of a sequential biological reactor (SBR) followed by ultrafiltration. Initially, grey water was treated in a laboratory SBR reactor with a capacity of 3 L, operated in a 24 h cycle. Then, SBR effluent was purified in a cross-flow ultrafiltration setup. Treatment efficiency in SBR and ultrafiltration was assessed using extended physicochemical and microbiological analyses (pH, conductivity, color, absorbance, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5), nitrate, phosphate, ammonium, total nitrogen, phenol index, nonionic and anionic surfactants, TOC, Escherichia coli, and enterococci). Additionally, ultrafiltration was evaluated in terms of fouling behavior for three polymer membranes with different MWCO (molecular weight cut-off). The values of quality parameters (pH, conductivity, COD, BOD5, TOC, N-NH4+, N-NO3−, Ntot, and P-PO43−) measured in SBR effluent did not exceed permissible values for wastewater discharged to soil and water. Ultrafiltration provided the high-quality water with very low values of COD (5.8–18.1 mg/L), TOC (0.47–2.19 mg/L), absorbanceUV254 (0.015–0.048 1/cm), color (10–29 mgPt/L) and concentration of nitrate (0.18–0.56 mg/L), phosphate (0.9–2.1 mg/L), ammonium (0.03–0.11 mg/L), and total nitrogen (3.3–4.7 mg/L) as well as lack of E. coli and enterococci. Membrane structural and surface properties did not affect the treatment efficiency, but did influence the fouling behavior.

Electrochemical advanced oxidation processes (EAOPs) as alternative treatment techniques for carwash wastewater reclamation

Electrochemical advanced oxidation processes such as electrooxidation (EO), electrooxidation with hydrogen peroxide generation (EO-H₂O₂) and electro-Fenton process (EF) have been investigated as alternative treatment techniques for complete removal of anionic surfactants and organic matters from real carwash wastewater. The electrochemical processes were performed with acidified real carwash wastewater using boron doped anode and carbon felt cathode. In all cases, the chemical oxygen demand (COD) removal efficiency was always increased with rise in applied current and complete organic matter decay was achieved at applied current of 500 mA or above after 6 h of electrolysis. Faster and higher COD decay was observed with EF compared to either EO or EO-H₂O₂ treatment, at all currents and electrolysis time. Besides, complete degradation of anionic surfactants - the major organic content of the wastewater could be achieved at all applied currents studied irrespective of the process used, indicating the efficacy of processes for total remediation of real carwash wastewater. The short-chain carboxylic acids formed as the final organic byproducts were identified and quantified by ion-exclusion chromatography. More so, lower energy consumption and higher current efficiency were achieved with EF compared to EO-H₂O₂. Electrochemical treatment was found to be a powerful technology for the complete abatement of organic matter in carwash wastewater for possible reuse.

Cationic Surfactant-modified Clay as an Adsorbent for the Removal of Synthetic Dyes from Aqueous Solutions

In this study, the potential of hexadecyl trimethyl ammonium bromide modified montmorillonite (HDTMA-Mt) to remove the synthetic dyes Alizarin Red S (ARS) and Bromocresol Green (BCG) from aqueous media was assessed. The effect of different factors including surfactant loading rate onto the clay, contact time, pH, adsorbent dosage and dye concentrations, on the removal of ARS and BCG in batch systems were investigated. The adsorbent was characterized by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD). The equilibrium time for ARS and BCG was reached at 40 and 20 min, respectively, under optimized conditions (i.e. pH = 3, adsorbent dosage=1 g/L, surfactant loading rate onto the clay 70% of the cation exchange capacity (CEC) for ARS and 120% of the CEC for BCG, ARS concentration 50 mg/L and BCG concentration 500 mg/L). The adsorption rate of both dyes fitted the pseudo-second-order kinetic model and the equilibrium data was described by the Freundlich isotherm equation. The maximum monolayer adsorption capacities were equal to 666.6 and 1250 mg/g for ARS and BCG, respectively. Therefore, the HDTMA-Mt can be considered as an effective adsorbent for the removal of ARS and BCG from aqueous solutions.

Geostatistical exploration of dataset assessing the heavy metal contamination in Ewekoro limestone, Southwestern Nigeria

The dataset for this article contains geostatistical analysis of heavy metals contamination from limestone samples collected from Ewekoro Formation in the eastern Dahomey basin, Ogun State Nigeria. The samples were manually collected and analysed using Microwave Plasma Atomic Absorption Spectrometer (MPAS). Analysis of the twenty different samples showed different levels of heavy metals concentration. The analysed nine elements are Arsenic, Mercury, Cadmium, Cobalt, Chromium, Nickel, Lead, Vanadium and Zinc. Descriptive statistics was used to explore the heavy metal concentrations individually. Pearson, Kendall tau and Spearman rho correlation coefficients was used to establish the relationships among the elements and the analysis of variance showed that there is a significant difference in the mean distribution of the heavy metals concentration within and between the groups of the 20 samples analysed. The dataset can provide insights into the health implications of the contaminants especially when the mean concentration levels of the heavy metals are compared with recommended regulatory limit concentration.

Exploration of solar radiation data from three geo-political zones in Nigeria

In this paper, readings of solar radiation received at three meteorological sites in Nigeria were analysed. Analysis of Variance (ANOVA) statistical test was carried out on the data set to observe the significant differences on radiations for each quarter of the specified years. The data were obtained in raw form from Nigerian Meteorological Agency (NIMET), Oshodi, Lagos. In order to get a clear description and visualization of the fluctuations of the radiation data, each year were considered independently, where it was discovered that for the 3rd quarter of each year, there is a great fall in the intensity of the solar radiation to as low as 73.27 (W/m²), 101.66 (W/m²), 158.51 (W/m²) for Ibadan, Port-Harcourt and Sokoto respectively. A detailed data description is available for the averages across months for each quarter. The data can provide insights on the health implications of exposure to solar radiation and the effect of solar radiation on climate change, food production, rainfall and flood patterns.

Adsorption of Congo Red Dye from Aqueous Solutions by Montmorillonite as a Low-cost Adsorbent

In this study, the sorption of Congo red (CR), as a toxic dye, from aqueous media was investigated using montmorillonite (MMT) as a low-cost adsorbent. The influence of several factors such as contact time, pH, adsorbent dosage, dye content, and ionic strength was investigated on the dye removal. MMT was characterized by Fourier transformed infrared (FTIR) spectroscopy and X-ray diffractometer (XRD). Different kinetic and isotherm models including pseudo-first and pseudo-second order kinetic and Langmuir and Freundlich were applied to analyze experimental data, respectively. The results showed that the data were well fitted by pseudo-second-order kinetic and Freundlich isotherm models. The optimum conditions for the sorption of CR were achieved over 40 min and at pH=2. According to the results of the present study, MMT can be used as a low-cost, eco-friendly and effective option for the adsorption of CR from aqueous solutions.