Search results for: wastewater treatment and desalination

Authors: Andrew Hargreaves, Peter Vale, Jonathan Whelan, Carlos Constantino, Gabriela Dotro, Pablo Campo

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As a consequence of their potential to cause harm, there are strong regulatory drivers that require metals to be removed as part of the wastewater treatment process. Bioavailability-based standards have recently been specified for copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) and are expected to reduce acceptable metal concentrations. In order to comply with these standards, wastewater treatment works may require new treatment types to enhance metal removal and it is, therefore, important to examine potential treatment options. A substantial proportion of Cu, Pb, Ni and Zn in effluent is adsorbed to and/or complexed with macromolecules (eg. proteins, polysaccharides, aminosugars etc.) that are present in the colloidal size fraction. Therefore, technologies such as coagulation-flocculation (CF) that are capable of removing colloidal particles have good potential to enhance metals removal from wastewater. The present study investigated the effectiveness of CF at removing trace metals from humus effluent using the following coagulants; ferric chloride (FeCl3), the synthetic polymer polyethyleneimine (PEI), and the biopolymers chitosan and Tanfloc. Effluent samples were collected from a trickling filter treatment works operating in the UK. Using jar tests, the influence of coagulant dosage and the velocity and time of the slow mixing stage were studied. Chitosan and PEI had a limited effect on the removal of trace metals (<35%). FeCl3 removed 48% Cu, 56% Pb and 41% Zn at the recommended dose of 0.10 mg/L. At the recommended dose of 0.25 mg/L Tanfloc removed 77% Cu, 68% Pb, 18% Ni and 42% Zn. The dominant mechanism for particle removal by FeCl3 was enmeshment in the precipitates (i.e. sweep flocculation) whereas, for Tanfloc, inter-particle bridging was the dominant removal mechanism. Overall, FeCl3 and Tanfloc were found to be most effective at removing trace metals from wastewater.

Keywords: coagulation-flocculation, jar test, trace metals, wastewater

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Authors: Sarra Kitanou

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Water recycling and reuse is an effective measure to solve the water stress problem. The sustainable use of water resource has become a national development strategy in Morocco. A key aspect of improving overall sustainability is the potential for direct wastewater effluent reuse. However, the hybrid technology membrane bioreactors (MBR) have been identified as an attractive option for producing high quality and nutrient-rich effluents for wastewater treatment. It is based on complex interactions between biological processes, filtration process and rheological properties of the liquid to be treated. Currently, with the evolution of wastewater treatment projects in Morocco, the MBR technology can be used as a technology treating different types of wastewaters and to produce effluent with suitable quality for reuse. However, the energetic consumption of this process is a great concern, which can limit the development and implementation of this technology. In this investigation, the electric energy consumption of an ultrafiltration membrane bioreactor process in domestic wastewater treatment is evaluated and compared to some MBR installations based on literature review. Energy requirements of the MBR are linked to operational parameters and reactor performance. The analysis of energy consumption shows that the biological aeration and membrane filtration are more energy consuming than the other components listed as feed and recirculation pumps. Biological aeration needs 53% of the overall energetic consumption and the specific energy consumption for membrane filtration is about 25%. However, aeration is a major energy consumer, often exceeding 50% share of total energy consumption. The optimal results obtained on the MBR process (pressure p = 1.15 bar), hydraulic retention time (15 h) showed removal efficiencies up to 90% in terms of organic compounds removal, 100% in terms of suspended solids presence and up to 80% reduction of total nitrogen and total phosphorus. The effluent from this MBR system could be considered as qualified for irrigation reuse, showing its potential application in the future.

Keywords: hybrid process, membrane bioreactor, wastewater treatment, reuse

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Authors: Suvidha Gupta, R. A. Pandey, Sanjay Pawar

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The effluents from various food processing industries are found with high BOD, COD, suspended solids, nitrate, and phosphate. Mixotrophic growth of microalgae using food processing industrial wastewater as an organic carbon source has emerged as more effective and energy intensive means for the nutrient removal and COD reduction. The present study details the treatment of non-sterilized unfiltered food processing industrial wastewater by microalgae for nutrient removal as well as to determine the tolerance to COD by taking different dilutions of wastewater. In addition, the effect of different inoculum percentages of microalgae on removal efficiency of the nutrients for given dilution has been studied. To see the effect of dilution and COD tolerance, the wastewater having initial COD 5000 mg/L (±5), nitrate 28 mg/L (±10), and phosphate 24 mg/L (±10) was diluted to get COD of 3000 mg/L and 1000 mg/L. The experiments were carried out in 1L conical flask by intermittent aeration with different inoculum percentage i.e. 10%, 20%, and 30% of Chlorella sp. isolated from nearby area of NEERI, Nagpur. The experiments were conducted for 6 days by providing 12:12 light- dark period and determined various parameters such as COD, TOC, NO3-- N, PO4-- P, and total solids on daily basis. Results revealed that, for 10% and 20% inoculum, over 90% COD and TOC reduction was obtained with wastewater containing COD of 3000 mg/L whereas over 80% COD and TOC reduction was obtained with wastewater containing COD of 1000 mg/L. Moreover, microalgae was found to tolerate wastewater containing COD 5000 mg/L and obtained over 60% and 80% reduction in COD and TOC respectively. The obtained results were found similar with 10% and 20% inoculum in all COD dilutions whereas for 30% inoculum over 60% COD and 70% TOC reduction was obtained. In case of nutrient removal, over 70% nitrate removal and 45% phosphate removal was obtained with 20% inoculum in all dilutions. The obtained results indicated that Microalgae assisted nutrient removal gives maximum COD and TOC reduction with 3000 mg/L COD and 20% inoculum. Hence, microalgae assisted wastewater treatment is not only effective for removal of nutrients but also can tolerate high COD up to 5000 mg/L and solid content.

Keywords: Chlorella sp., chemical oxygen demand, food processing industrial wastewater, mixotrophic growth

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Authors: Habtamu Abdisa

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In nature, water may not be free from contaminants due to its polar nature. But, more than this, the environmental water is highly polluted by manmade activities from industrial, agricultural, recreation, shipping, and domestic sites, thereby increasing the shortage of freshwater for designated purposes. Therefore, in the face of water scarcity, human beings are enforced to look at all the existing opportunities to get an adequate amount of freshwater resources. The most probable water resource is wastewater, from which the water can be recovered to serve designated purposes (for industrial, agricultural, drinking, and other domestic uses). Present-day, the most preferable method for recovering water from different wastewater streams for re-use is membrane technology. This paper looks at the progressive development of membrane technology in wastewater treatment. The applications of pressure-driven membrane separation technology (microfiltration, ultrafiltration, nano-filtration, reverse osmosis, and tissue purification) and no pressure membrane separation technology (semipermeable membrane, liquefiedfilm, and electro-dialysis) and also ion-exchange were reviewed. More than all, the technology for converting environmental water pollutants into energy is of considerable attention. Finally, recommendations for future research relating to the application of membrane technology in wastewater treatment were made. Also, further research recommendation about membrane fouling and cleaning was made.

Keywords: environmental pollution, membrane technology, water quality, wastewater

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Authors: Boudjema Nouara, Mameri Nabil

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Bacteria have played an important role in water contamination as a consequence of organic pollution. In this study, an electrocoagulation process was adopted to remove fecal contamination and pathogenic bacteria from waste water. The effect of anode/cathodes materials as well as operating conditions for bacteria removal from water, such as current intensity and initial pH and temperature. The results indicated that the complete removal was achevied when using aluminium anode as anode at current intensity of 3A, initial pH of 7-8 and electrolysis time of 30 minutes. This process showed a bactericidal effect of 95 to 99% for the total and fecal coliforms and 99% to 100% for Eschercichia coli and fecal Streptococci. A decrease of 72% was recorded for sulphite-reducing Clostridia. Thus, this process has the potential to be one the options for treatment where high amount of bacteria in wastewater river.

Keywords: bacteria, el Harrach river, electrocoagulation, wastewater, treatment

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Authors: Hanish Mohammed, C. H. Muthukumar Muthuchamy

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The advancement in the science and technology has made it possible to convert electrical energy into any desired form. It has given electrical energy a place of pride in the modern world. The survival of industrial undertakings and our social structure depends primarily upon low cost and uninterrupted supply of electrical energy. Microbial fuel cell (MFC) is a promising and emerging technique for sustainable bioelectricity generation and wastewater treatment. MFCs are devices which are capable of converting organic matter to electricity/hydrogen with help of microorganisms. Different kinds of wastewater could be used in this technique, distillery effluent is one of the most troublesome and complex and strong organic effluent with high chemical oxygen demand of 1,53,846 mg/L. A single cell MFC unit was designed and fabricated for the distillery effluent treatment and to generate electricity. Due to the high COD value of the distillery effluent helped in the production of energy for 74 days. The highest voltage got from the fuel cell is 206 mV on the 30th day. A maximum power density obtained from the MFC was 9.8 mW, treatment efficiency was evaluated in terms of COD removal and other parameters. COD removal efficiencies were around 68.5 % and other parameters such as Total Hardness (81.5%), turbidity (70 %), chloride (66%), phosphate (79.5%), Nitrate (77%) and sulphate (71%). MFC using distillery effluent is a promising new unexplored substrate for the power generation and sustainable treatment technique through harnessing of bioelectricity.

Keywords: microbial fuel cell (MFC), bioelectricity, distillery effluent, wastewater treatment

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Authors: Alemi Asefa Wordofa

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The textile industry is among the biggest industries in the world, producing a wide variety of products. Industry plays an important role in the world economy as well as in our daily lives. In Ethiopia, this has also been aided by the country’s impressive economic growth over the years. However, Textile industries consume large amounts of water and produce colored wastewater, which results in polluting the environment. In this study, the efficiency of the electrocoagulation treatment process using Iron electrodes to treat textile wastewater containing Reactive black everzol was studied. The effects of parameters such as voltage, time of reaction, and inter-electrode distance on Chemical oxygen demand (COD) and dye removal efficiency were investigated. In addition, electrical energy consumption at optimum conditions has been investigated. The results showed that COD and dye removals were 90.76% and 97.66%, respectively, at the optimum point of input voltage of 14v, inter-electrode distance of 7.24mm, and 47.86min electrolysis time. Energy consumption at the optimum point is also 2.9*10-3. It can be concluded that the electrocoagulation process by the iron electrode is a very efficient and clean process for COD and reactive black removal from wastewater.

Keywords: iron electrode, electrocoagulation, chemical oxygen demand, wastewater

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Authors: Seyed Mohsen Samaei, Shirley Gato-Trinidad

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A pre-treatment stage prior to reverse osmosis (RO) is very important to ensure the long-term performance of the RO membranes in any wastewater treatment using RO. This study aims to evaluate the application of the Actiflo^® clarifier as part of a pre-treatment unit in mining operations. It involves performing analytical testing on RO feed water before and after installation of Actiflo^® unit. Water samples prior to RO plant stage were obtained on different dates from Costerfield mining operations in Victoria, Australia. Tests were conducted in an independent laboratory to determine the concentration of various compounds in RO feed water before and after installation of Actiflo^® unit during the entire evaluated period from December 2015 to June 2018. Water quality analysis shows that the quality of RO feed water has remarkably improved since installation of Actiflo^® clarifier. Suspended solids (SS) and turbidity removal efficiencies has been improved by 91 and 85 percent respectively in pre-treatment system since the installation of Actiflo^®. The Actiflo^® clarifier proved to be a valuable part of pre-treatment system prior to RO. It has the potential to conveniently condition the mining wastewater prior to RO unit, and reduce the risk of RO physical failure and irreversible fouling. Consequently, reliable and durable operation of RO unit with minimum requirement for RO membrane replacement is expected with Actiflo^® in use.

Keywords: ACTIFLO ® clarifier, mining wastewater, reverse osmosis, water treatment

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Authors: Peter G. Youssef, Saad M. Mahmoud, Raya K. AL-Dadah

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Many water desalination technologies have been developed but in general they are energy intensive and have high cost and adverse environmental impact. Recently, adsorption technology for water desalination has been investigated showing the potential of using low temperature waste heat (50-85oC) thus reducing energy consumption and CO2 emissions. This work mathematically compares the performance of an adsorption cycle that produces two useful effects namely, fresh water and cooling using two different adsorbents, silica-gel and an advanced zeolite material AQSOA-ZO2, produced by Mitsubishi plastics. It was found that at low chilled water temperatures, typically below 20oC, the AQSOA-Z02 is more efficient than silica-gel as the cycle can produce 5.8 m3 of fresh water per day and 50.1 Rton of cooling per tonne of AQSOA-ZO2. Above 20oC silica-gel is still better as the cycle production reaches 8.4 m3 per day and 62.4 Rton per tonne of silica-gel. These results show the potential of using the AQSOA-Z02 at low chilled water temperature for water desalination and cooling applications.

Keywords: adsorption, desalination, refrigeration, seawater

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Authors: Aderonke A. Okoya, Oluwaseun A. Somoye, Omotayo S. Amuda, Ifeanyi E. Ofoezie

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This study assessed the efficiency of Hydroxyapatite Powder (HAP) in the removal of dyes in wastewater in comparison with Commercial Activated Carbon (CAC). This was with a view to developing cost effective method that could be more environment friendly. The HAP and CAC were used as adsorbent while Indigo dye was used as the adsorbate. The batch adsorption experiment was carried out by varying initial concentrations of the indigo dye, contact time and adsorbent dosage. Adsorption efficiency was classified by adsorption Isotherms using Langmuir, Freundlich and D-R isotherm models. Physicochemical parameters of a textile industry wastewater were determined before and after treatment with the adsorbents. The results from the batch experiments showed that at initial concentration of 125 mg/L of adsorbate in simulated wastewater, 0.9276 ± 0.004618 mg/g and 3.121 ± 0.006928 mg/g of indigo adsorbed per unit time (qt) of HAP and CAC respectively. The ratio of HAP to CAC required for the removal of indigo dye in simulated wastewater was 2:1. The isotherm model of the simulated wastewater fitted well to Freundlich model, the adsorption intensity (1/n) presented 1.399 and 0.564 for HAP and CAC, respectively. This revealed that the HAP had weaker bond than the electrostatic interactions which were present in CAC. The values of some physicochemical parameters (acidity, COD, Cr, Cd) of textile wastewater when treated with HAP decreased. The study concluded that HAP, an environment-friendly adsorbent, could be effectively used to remove dye from textile industrial wastewater with added advantage of being regenerated.

Keywords: adsorption isotherm, commercial activated carbon, hydroxyapatite powder, indigo dye, textile wastewater

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Authors: Nihad Chakri, Btissam El Amrani, Faouzi Berrada, Fouad Amraoui

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In Morocco, water scarcity requires the exploitation of non-conventional resources. Rural areas are under-equipped with sanitation infrastructure, unlike urban areas. Decentralized and low-cost solutions could improve the quality of life of the population and the environment. In this context, the Faculty of Sciences Ain Chock "FSAC" has undertaken an integrated project to treat part of its wastewater using a decentralized compact system. The project will propose alternative solutions that are inexpensive and adapted to the context of peri-urban and rural areas in order to treat the wastewater generated and use it for irrigation, watering, and cleaning. For this purpose, several tests were carried out in the laboratory in order to develop a liquid waste treatment system optimized for local conditions. Based on the results obtained at the laboratory scale of the different proposed scenarios, we designed and implemented a prototype of a mini wastewater treatment plant for the Faculty. In this article, we will outline the steps of dimensioning, construction, and monitoring of the mini-station in our Faculty.

Keywords: wastewater, purification, optimization, vertical filter, MBBR process, sizing, decentralized pilot, reuse, irrigation, sustainable development

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Authors: Iga Maliga

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As developing country, Indonesia, retreatment for greywater is an important factor that guaranteeing water sustainability? But, its still not familiar in Indonesian society. Because they still use their old habit for wasting the water without retreatment. Differently, with industry wastewater, effect of domestic wastewater is not directly looked with naked eyes. Domestic wastewater that not gets treatment directly can affect pollution in water body or river. Its affected by accumulation many pollutants that include on water. This paper is trying to analyze the challenges and advantages on greywater treatment system based on Constructed Wetlands (CWs) system in Bandung, one of the biggest cities in Indonesia. Aside that, this paper also is trying to analyze sustainability aspects. There is economic, social and of course environment with two methods. The first, study literature is used to see the advantages and challenges that faced by Indonesia when CWs are applied. Secondly, quantitative method is used to get the society perception about retreatment of greywater. Then, it will get a conclusion that this technique not only good in theoretically but also practically.

Keywords: greywater, constructed wetlands, advantages, challenges, Bandung, sustainability analysis

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Authors: Lingfeng Wang, Zhipeng Chen, Shuang Qiu, Shijian Ge

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The effects of wastewater, with four different nutrient loadings, from synthetic centrate on biomass production of Chlorella vulgaris, nutrient removal, microalgal settling, and lipid production were investigated in photobioreactors under both batches and, subsequently, semi-continuous operations. At higher centrate concentration factors (17.2% and 36.2%), hydraulic retention time and pH adjustments could be employed to sustain acceptable microalgal growth rates and wastewater treatment. Similar nutrient removals efficiencies (>95%) and biomass production (0.42-0.51 g/L) were observed for the four centrate concentrations. Both the lipid productivity and lipid content decreased with increasing nutrient loading in the wastewater. The results also demonstrated that the mass ratio of carbohydrate to protein could provide a good indication of microalgal settling performance, rather than sole component composition or total extracellular polymeric substances.

Keywords: lipid production, microalgae, nutrient removal, wastewater

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Authors: Pham-Thi Huong, Byeong-Kyu Lee, Chi-Hyeon Lee, JiTae Kim

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This study analyzed the removal of p-nitrophenol from wastewater using Fe-nano zeolite synthesized. The basic physical-chemical properties of Fe-nano zeolite was determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy. We focus on finding out the optimum conditions in adsorption and desorption processes for removal of p-nitrophenol by using Fe-nano zeolite in wastewater. The optimum pH for p-nitrophenol removal in wastewater was 5.0. Adsorption isotherms were better fitted with the Langmuir isotherm than with the Freundlich with 165.58 mg/g adsorption capacity of p-nitrophenol. These findings support potential of Fe-nano zeolite as an effective adsorbent for p-nitrophenol removal from wastewater.

Keywords: Fe-nano zeolite, adsorption, wastewater, regeneration

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Authors: Susmita Sharma, Pankaj Pathak

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Biosolids are by-products of municipal and industrial wastewater treatment process. The generation of the biosolids is increasing at an alarming rate due to the implementation of strict environmental legislation to improve the quality of discharges from wastewater treatment plant. As such, proper management and safe disposal of sewage sludge have become a worldwide topic of research. Biosolids, rich in organic matter and essential micro and macronutrients; can be used as a soil conditioner, to cut fertilizer costs and create favorable conditions for vegetation. However, it also contains pathogens and heavy metals which are undesirable as they are harmful to both humans and the environment. Therefore, for safe utilization of biosolids for land application purposes, categorization of the contaminant and pathogen is mandatory. In this context, biosolids collected from a wastewater treatment plant in Maharashtra are utilized to determine its physical, chemical and microbiological attributes. This study would ascertain, if the use of these materials from the specific site, are suitable for agriculture. Further, efforts have also been made to present the internationally acceptable legal standards and guidelines for biosolids management or application.

Keywords: biosolids, sewage, heavy metal, sustainable agriculture

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Authors: Khedidja Benouis

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Environmental issues in the food industry are related to the water because it consumes water and release large volumes of wastewater. The treatment of such discharges techniques can be adapted to different situations encountered. For dairy effluents, it is necessary and very effective to use a treatment that eliminates much of the pollutant load,thus, to drastically reduce the organic loading rate. This study aims to evaluate the Efficiency and limitations of physicochemical treatment by coagulation - flocculation of liquid effluent from this type of food industry in Algeria, to give an example of the type and the degree of pollution generated by this sector and in order to reduce pollution and minimize its environmental issues. Coagulation - flocculation-sedimentation was carried out using lime without addition of additive (flocculant), the processing efficiency is indicated by the concentration of pollutants in treated water. The results show that treatment is not sufficient to remove organic pollution, but it has significantly reduced the Total suspended solids (TSS), nitrate (NO3-N) and phosphate (PO4-P).

Keywords: Algeria, coagulation-flocculation, dairy effluent, treatment

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Authors: Hakim Aguedal, Abdelkader Iddou, Abdallah Aziz, Djillali Reda Merouani, Ferhat Bensaleh, Saleh Bensadek

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The textile industry produces high amount of colored effluent each year. The management or treatment of these discharges depends on the applied techniques. Adsorption is one of wastewater treatment techniques destined to treat this kind of pollution, and the performance and efficiency predominantly depend on the nature of the adsorbent used. Therefore, scientific research is directed towards the development of new materials using different physical and chemical treatments to improve their adsorption capacities. In the same perspective, we looked at the effect of the heat treatment on the effectiveness of diatomite, which is found in abundance in Algeria. The textile dye Orange Bezaktiv (SRL-150) which is used as organic pollutants in this study is provided by the textile company SOITEXHAM in Oran city (west Algeria). The effect of different physicochemical parameters on the adsorption of SRL-150 on natural and modified diatomite is studied, and the results of the kinetics and adsorption isotherms were modeled.

Keywords: wastewater treatment, diatomite, adsorption, dye pollution, kinetic, isotherm

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Authors: Arwa Abdelhay, Inshad Jum’h, Abeer Albsoul, Khalideh Alrawashdeh, Dina Al Tarazi

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Treated wastewater reuse has been considered recently as one of the successful management strategies to overcome water shortage in countries suffering from water scarcity. The non-readily biodegradable and recalcitrant pollutants in wastewater cannot be destructed by conventional treatment methods. This paper deals with the electrochemical treatment of dairy wastewater using a promising non-conventional Boron-Doped Diamond (BDD) anode. During the electrochemical process, different operating parameters were investigated, such as electrolysis time, current density, supporting electrolyte, chemical oxygen demand (COD), turbidity as well as absorbance/color. The experimental work revealed that electrochemical oxidation carried out with no added electrolyte has significantly reduced the COD, turbidity, and color (absorbance) by 72%, 76%, and 78% respectively. Results also showed that raising the current density from 5.1 mA/cm² to 7.7 mA/cm² has boosted COD, and color removal to 82.5%, and 83% respectively. However, the current density did not show any significant effect on the turbidity. Interestingly, it was observed that adding Na₂SO₄ and FeCl₃ as supporting electrolytes brought the COD removal to 91% and 97% respectively. Likewise, turbidity and color removal has been enhanced by the addition of the same supporting electrolytes.

Keywords: boron doped-diamond anode, dairy wastewater, electrochemical oxidation, supporting electrolytes

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Authors: Hsien T. Hsieh, Chao R. Chen, Li C. Chuang, Chin C. Shen

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Fenton oxidation technology is the general strategy for the treatment of organic compounds-contained wastewater. However, a considerable amount of ferric sludge was produced during the Fenton process as secondary wastes, which were needed to be further removed from the effluent and treated. In this study, heterogeneous catalysts based on ferrite oxide (Cu-Fe-Ce-O) were synthesized and characterized, and their application for Fenton-like oxidation of simulated and actual radioactive organic wastewater was investigated. The results of TOC decomposition efficiency around 54% ~ 99% were obtained when the catalyst loading, H₂O₂ loading, pH, temperature, and reaction time were controlled. In this case, no secondary wastes formed and the given catalysts were able to be separated by magnetic devices and reused again.

Keywords: fenton, oxidation, heterogeneous catalyst, wastewater

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Authors: Yasser El-Henawy, M. Abd El-Kader, Gamal H. Moustafa

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A theoretical study of a humidification dehumidification solar desalination unit has been carried out to increase understanding the effect of weather conditions on the unit productivity. A humidification-dehumidification (HD) solar desalination unit has been designed to provide fresh water for population in remote arid areas. It consists of solar water collector and air collector; to provide the hot water and air to the desalination chamber. The desalination chamber is divided into humidification and dehumidification towers. The circulation of air between the two towers is maintained by the forced convection. A mathematical model has been formulated, in which the thermodynamic relations were used to study the flow, heat and mass transfer inside the humidifier and dehumidifier. The present technique is performed in order to increase the unit performance. Heat and mass balance has been done and a set of governing equations has been solved using the finite difference technique. The unit productivity has been calculated along the working day during the summer and winter sessions and has compared with the available experimental results. The average accumulative productivity of the system in winter has been ranged between 2.5 to 4 kg/m2.day, while the average summer productivity has been found between 8 to 12 kg/m2 day.

Keywords: solar desalination, solar collector, humidification and dehumidification, simulation, finite difference, water productivity

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Authors: Luciana P. Mazur, Tatiana A. Pozdniakova, Rui A. R. Boaventura, Vitor J. P. Vilar

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The electroplating industry requires a lot of process water, which generates a large volume of wastewater loaded with heavy metals. Two different wastewaters were collected in a company’s wastewater treatment plant, one after the use of zinc in the metal plating process and the other after the use of chromium. The main characteristics of the Zn(II) and Cr(VI) wastewaters are: pH = 6.7/5.9; chemical oxygen demand = 55/<5 mg/L; sodium, potassium, magnesium and calcium ions concentrations of 326/28, 4/28, 11/7 and 46/37 mg/L, respectively; zinc(II) = 11 mg/L and Cr(VI) = 39 mg/L. Batch studies showed that L. hyperborea can be established as a natural cation exchanger for heavy metals uptake mainly due to the presence of negatively charged functional groups in the surface of the biomass. Beyond that, L. hyperborea can be used as a natural electron donor for hexavalent chromium reduction to trivalent chromium at acidic medium through the oxidation of the biomass, and Cr(III) can be further bound to the negatively charged functional groups. The uptake capacity of Cr(III) by the oxidized biomass after Cr(VI) reduction was higher than by the algae in its original form. This can be attributed to the oxidation of the biomass during Cr(VI) reduction, turning other active sites available for Cr(III) binding. The brown macroalgae Laminaria hyperborea was packed in a fixed-bed column in order to evaluate the feasibility of the system for the continuous treatment of the two galvanization wastewaters. The column, with an internal diameter of 4.8 cm, was packed with 59 g of algae up to a bed height of 27 cm. The operation strategy adopted for the treatment of the two wastewaters consisted in: i) treatment of the Zn(II) wastewater in the first sorption cycle; ii) desorption of pre-loaded Zn(II) using an 1.0 M HCl solution; iii) treatment of the Cr(VI) wastewater, taking advantage of the acidic conditions of the column after the desorption cycle, for the reduction of the Cr(VI) to Cr(III), in the presence of the electrons resulting from the biomass oxidation. This cycle ends when all the oxidizing groups are used.

Keywords: biosorption, brown marine macroalgae, zinc, chromium

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Authors: Monika Gałwa-Widera, Anna Kwarciak–Kozłowska, Lucyna Sławik-Dembiczak

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Issues relating to management of sewage sludge from small and medium-sized wastewater treatment plants is a vital issue, which deal with such scholars as well as those directly involved in the issue of wastewater treatment and management of sedimentary. According to the Law on Waste generating waste is responsible for such processing to the product obtained impacted on the environment minimally. In small and medium-sized wastewater treatment plants have to deal with the technology of sludge management technology is far from drying and incineration of sewage sludge. So here you can use other technologies. One of them is the composting of sewage sludge. It is a process of processing and disposal of sewage sludge that effectively their disposal. By composting, we can obtain a product that contains significant amounts of organic matter to assess the fertilizing qualities. Modifications to the ongoing process in biological reactors allow for more rapid receipt of a wholesome product. The research presented and discussed in this publication relate to assist the composting process of sewage sludge and biomass structural material in the shares of rates: 35% biomass, 55% sludge, 10% structural material using a method which involves the re-spawning batch composting physical methods leachate from the composting process.

Keywords: biomass, composting, industry, sewage sludge

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Authors: Zied Guidara, Alexander Morgenstern, Aref Younes Maalej

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In this paper, a desiccant solar unit for air conditioning and desalination is presented first. Secondly, a dynamic modelling study of the desiccant wheel is developed. After that, a simulation study and an experimental investigation of the behaviour of desiccant wheel are developed. The experimental investigation is done in the chamber of commerce in Freiburg-Germany. Indeed, the variations of calculated and measured temperatures and specific humidity of dehumidified and rejected air are presented where a good agreement is found when comparing the model predictions with experimental data under the considered range of operating conditions. Finally, the study of the compartments of desalination and water condensation shows that the unit can produce an acceptable quantity of water at the same time of the air conditioning operation.

Keywords: air conditioning, desalination, condensation, design, desiccant wheel

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Authors: Vitool Suksankavanich

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This preliminary research aimed to explore the development of wastewater management of Bang Pu Sub- District Municipality, Samutprakan Province, in order to establish appropriate model for effective wastewater management that fit to the context of the area. The research posed three questions: [i] to what extent the promotion of social responsibility awareness built among the local community resulted in effectiveness of the local wastewater management; [ii] did the waste disposal management of Bang Pu Industrial Estate contribute to the overall environmental quality of Bang Pu Sub- District Municipality; and [iii] did the relationship between the community and the industrial factories have any effect on the wastewater management. The in- depth interview revealed main obstacles occurred in the process of wastewater management in the area. The fieldwork also contributed to a product of an appropriate model of effective wastewater management.

Keywords: legitimacy theory, stakeholder theory, social responsibility, wastewater management

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Authors: Hady Hamidyan

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As the global population continues to grow, the demand for clean water and effective wastewater treatment becomes increasingly critical. By 2030, global water demand is projected to exceed supply by 40%, driven by population growth, increased water usage, and climate change. Currently, about 4.2 billion people lack access to safely managed sanitation services. The wastewater treatment sector faces numerous challenges, including the need for energy-efficient solutions, cost-effectiveness, ease of use, and low maintenance requirements. This abstract presents a groundbreaking wastewater treatment technology that addresses these challenges by offering an energy-saving approach, wastewater recovery capabilities, and a ready-made, affordable, and user-friendly package with minimal maintenance costs. The unique design of this ready-made package made it possible to eliminate the need for pumps, filters, airlift, and other common equipment. Consequently, it enables sustainable wastewater treatment management with exceptionally low energy and cost requirements, minimizing investment and maintenance expenses. The operation of these packages is based on continuous aeration, which involves injecting oxygen gas or air into the aeration chamber through a tubular diffuser with very small openings. This process supplies the necessary oxygen for aerobic bacteria. The recovered water, which amounts to almost 95% of the input, can be treated to meet specific quality standards, allowing safe reuse for irrigation, industrial processes, or even potable purposes. This not only reduces the strain on freshwater resources but also provides economic benefits by offsetting the costs associated with freshwater acquisition and wastewater discharge. The ready-made, affordable, and user-friendly nature of this technology makes it accessible to a wide range of users, including small communities, industries, and decentralized wastewater treatment systems. The system incorporates user-friendly interfaces, simplified operational procedures, and integrated automation, facilitating easy implementation and operation. Additionally, the use of durable materials, efficient equipment, and advanced monitoring systems significantly reduces maintenance requirements, resulting in low overall life-cycle costs and alleviating the burden on operators and maintenance personnel. In conclusion, the presented wastewater treatment technology offers a comprehensive solution to the challenges faced by the industry. Its energy-saving approach, combined with wastewater recovery capabilities, ensures sustainable resource management and enhances environmental stewardship. This affordable, ready-made, and low-maintenance package promotes broad adoption across various sectors and communities, contributing to a more sustainable future for water and wastewater management.

Keywords: wastewater treatment, energy saving, wastewater recovery, affordable package, low maintenance costs, sustainable resource management, environmental stewardship

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Authors: C. A Osunla, A. I. Okoh

Abstract:

Treated wastewater effluent has been found to encompass high levels of pollutants, including disease-causing bacteria such as Vibrio pathogens. The current study was designed to evaluate the physicochemical qualities and prevalence of Vibrio pathogens in treated effluents of two wastewater treatment plants (WWTP) in Eastern Cape Province, South Africa over the period of six months. Parameters measured include pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solid (TDS), dissolved oxygen (DO), and free chlorine; and these parameters were simultaneously monitored in the treated final effluents of the two wastewater treatment plants using standard methods. The ranges of values for the physicochemical are: pH (7.0–8.6), total dissolved solids (286.3–916.5 mg/L), electrical conductivity (572.57–1704.5 mS/m), temperature (10.3–28.6 °C), turbidity (4.02–43.20 NTU), free chlorine (0.00–0.19 mg/L), dissolve oxygen (2.06–6.32 mg/L) and biochemical oxygen demand (0.1–9.0 mg/L). The microbiological assessment for both WWTPs revealed the presence of Vibrio counts ranging between 0 and 8.76×104 CFU/100 mL. The obtained values of the measured parameters and Vibrio loads of the treated wastewater effluents were found outside the compliance levels of the South African guidelines and World Health Organization tolerance limits for effluents intended to be discharged into receiving waterbodies. Hence, we conclude that these WWTPs are important point sources of pollution in surface water with potential public health and ecological risks.

Keywords: effluents, public health, South Africa, Vibrio, wastewater

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Authors: Sabri Mrayed, David Maccioni, Greg Leslie

Abstract:

Seawater desalination has been accepted as one of the most effective solutions to the growing problem of a diminishing clean drinking water supply. Currently, two desalination technologies dominate the market – the thermally driven multi-stage flash distillation (MSF) and the membrane based reverse osmosis (RO). However, in recent years membrane distillation (MD) has emerged as a potential alternative to the established means of desalination. This research project intended to determine the viability of MD as an alternative process to MSF and RO for seawater desalination. Specifically the project involves conducting a thermodynamic analysis of the process based on the second law of thermodynamics to determine the efficiency of the MD. Data was obtained from experiments carried out on a laboratory rig. In order to determine exergy values required for the exergy analysis, two separate models were built in Engineering Equation Solver – the ’Minimum Separation Work Model’ and the ‘Stream Exergy Model’. The efficiency of MD process was found to be 17.3 %, and the energy consumption was determined to be 4.5 kWh to produce one cubic meter of fresh water. The results indicate MD has potential as a technique for seawater desalination compared to RO and MSF. However, it was shown that this was only the case if an alternate energy source such as green or waste energy was available to provide the thermal energy input to the process. If the process was required to power itself, it was shown to be highly inefficient and in no way thermodynamically viable as a commercial desalination process.

Keywords: desalination, exergy, membrane distillation, second law efficiency

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Authors: Christine A. Odinga, G. Sanjay, M. Mathew, S. Gupta, F. M. Swalaha, F. A. O. Otieno, F. Bux

Abstract:

Wastewater discharged from municipal treatment plants contain an amalgamation of trace metals. The presence of metal pollutants in wastewater poses a huge challenge to the choice and applications of the preferred treatment method. Conventional treatment methods are inefficient in the removal of trace metals due to their design approach. This study evaluated the treatment performance of a constructed rhizofiltration system in the removal of heavy metals from municipal wastewater. The study was conducted at an eThekwni municipal wastewater treatment plant in Kingsburgh - Durban in the province of KwaZulu-Natal. The construction details of the pilot-scale rhizofiltration unit included three different layers of substrate consisting of medium stones, coarse gravel and fine sand. The system had one section planted with Phragmites australis L. and Kyllinga nemoralis L. while the other section was unplanted and acted as the control. Influent, effluent and sediment from the system were sampled and assessed for the presence of and removal of selected trace heavy metals using standard methods. Efficiency of metals removal was established by gauging the transfer of metals into leaves, roots and stem of the plants by calculations based on standard statistical packages. The Langmuir model was used to assess the heavy metal adsorption mechanisms of the plants. Heavy metals were accumulated in the entire rhizofiltration system at varying percentages of 96.69% on planted and 48.98% on control side for cadmium. Chromium was 81% and 24%, Copper was 23.4% and 1.1%, Nickel was 72% and 46.5, Lead was 63% and 31%, while Zinc was 76% and 84% on the on the water and sediment of the planted and control sides of the rhizofilter respectively. The decrease in metal adsorption efficiencies on the planted side followed the pattern of Cd>Cr>Zn>Ni>Pb>Cu and Ni>Cd>Pb>Cr>Cu>Zn on the control side. Confirmatory analysis using Electron Scanning Microscopy revealed that higher amounts of metals was deposited in the root system with values ranging from 0.015mg/kg (Cr), 0.250 (Cu), 0.030 (Pb) for P. australis, and 0.055mg/kg (Cr), 0.470mg/kg (Cu) and 0.210mg/kg,(Pb) for K. nemoralis respectively. The system was found to be efficient in removing and reducing metals from wastewater and further research is necessary to establish the immediate mechanisms that the plants display in order to achieve these reductions.

Keywords: wastewater treatment, Phragmites australis L., Kyllinga nemoralis L., heavy metals, pathogens, rhizofiltration

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Authors: Abdou Khafor Ndiaye

Abstract:

The article examines clean water and sanitation in Saint-Louis region schools. It finds that 59% have clean water, with disparities between departments, urban/rural areas, and school types. Podor and Dagana lack water due to distance and costs. 70% have sanitation, but rural schools lack it due to low investment. Podor and Dagana suffer the most. Many sanitation facilities need renovation. Wastewater treatment is effective, reducing pollutants and nitrogen, but adjustments are needed for nitrates. Treated water meets Senegalese standards and can be used for irrigation but needs monitoring for strict standards. In conclusion, the wastewater system is good for regions with limited water. Meeting stricter European standards and monitoring for health and environmental standards are needed.

Keywords: water, constructed wetland, sanitation, hygiene

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Authors: Pradipta Risang Ratna Sambawa, Driya Herseta, Mahendra Fajri Nugraha

Abstract:

In 2020, PT Petrokimia Gresik implemented a program to increase the ROP (Run Of Pile) production rate at the Phosphate Fertilizer 1 plant, causing an increase in scrubbing water consumption in the 100/200 area unit. This increase in water consumption causes a higher discharge of wastewater, which can further cause local flooding, especially during the rainy season. The 100/200 area of the Phosphate Fertilizer 1 plant is close to the warehouse and is often a passing area for trucks transporting raw materials. This causes the pH in the wastewater to become acidic (the worst point is up to pH 1). The problem of flooding and exposure to acidic wastewater in the 100/200 area of Phosphate Fertilizer Plant 1 was then resolved by PT Petrokimia Gresik through wastewater optimization steps called the 3R program (Reduce, Reuse, and Recycle). The 3R (Reduce, reuse, and recycle) program consists of an air consumption reduction program by considering the liquid/gas ratio in scrubbing unit of 100/200 Phosphate Fertilizer 1 plant, creating a wastewater interconnection line so that wastewater from unit 100/200 can be used as scrubbing water in the Phonska 1, Phonska 2, Phonska 3 and unit 300 Phosphate Fertilizer 1 plant and increasing scrubbing effectiveness through scrubbing effectiveness simulations. Through a series of wastewater optimization programs, PT Petrokimia Gresik has succeeded in reducing NaOH consumption for neutralization up to 2,880 kg/day or equivalent in saving up to 314,359.76 dollars/year and reducing process water consumption up to 600 m3/day or equivalent in saving up to 63,739.62 dollars/year.

Keywords: fertilizer, phosphate fertilizer, wastewater, wastewater treatment, water management

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