Wastewater treatment using a natural coagulant (Moringa oleifera seeds): optimization through response surface methodology

Recent progress and perspectives of typical renewable bio-based flocculants: characteristics and application in wastewater treatment

The research on bio-based flocculants for waste resource utilization and environmental protection has garnered significant attention. Bio-based flocculants encompass plant-based, animal-based, and microbial variants that are prepared and modified through biological, chemical, and physical methods. These flocculants possess abundant functional groups, unique structures, and distinctive characteristics. This review comprehensively discussed the removal rates of conventional pollutants and emerging pollutants by bio-based flocculants, the interaction between these flocculants and pollutants, their impact on flocculation performance in wastewater treatment, as well as their application cost. Furthermore, it described the common challenges faced by bio-based flocculants in practical applications along with various improvement strategies to address them. With their safety profile, environmental friendliness, efficiency, renewability, and wide availability from diverse sources, bio-based flocculants hold great potential for widespread use in wastewater treatment.

Optimization use of watermelon rind in the coagulation-flocculation process by Box Behnken design for copper, zinc, and turbidity removal

Watermelon rinds were investigated as a bio-coagulant for treating water contaminated by metals and turbidity, owing to their biodegradability and greater environmental friendliness compared to chemical coagulants. Fourier transform infrared spectroscopy, scanning electron microscopy paired with energy dispersive X-ray analysis and X-ray diffraction characterized the watermelon rinds before and after use. A Box-Behnken experimental design optimized the most influential parameters of initial pH, coagulant dose, and particle size based on response surface methodology. This analysis revealed the experimental data fit quadratic polynomial models, achieving maximum removal efficiencies of 97.51 % for zinc, 99.88 % for copper, and 99.21 % for turbidity under optimal conditions. Statistical analysis confirmed the models effectively captured the experimental data. Analysis of variance denoted the high significance of the quadratic effects of dose and pH. Removal of metal ions Zn2+ and Cu2+ was significantly impacted by these factors. The watermelon rind powder retained its coagulation efficiency after five cycles of reuse, with removal rates of 80.04 % for Zn, 88.33 % for Cu and 86.24 % for turbidity. These results demonstrate the potential of watermelon rind as an alternative coagulant for wastewater treatment. Further testing on real industrial effluents at larger scales would help assess their feasibility for real-world applications.

Coagulation process for the removal of color and turbidity from wet coffee processing industry wastewater using bio-coagulant: Optimization through central composite design

The growing problem of industrial pollution in developing countries, especially Ethiopia, has sparked serious issues about the quality of the water, particularly when it comes to the effluent from wet coffee processing industries. In response, this study investigates the potential of utilizing natural coagulants, Acanthus sennii C., Moringa stenopetala B., and Aloe vera L., either individually or in combination, for the treatment of coffee effluent. Methodologically, the study systematically varies operational parameters, including coagulant dose, pH levels, stirring speed, and stirring time, to evaluate their impact on coagulation efficiency. Experimental data undergo statistical analysis, employing ANOVA, while computational optimization techniques are employed using Design Expert software to determine optimal conditions. Notably, the blended form of the three coagulants emerges as particularly promising, yielding optimal conditions of 0.750 g/L coagulant dosage, pH 8.76, agitation speed of 80.73 rpm, and agitation time of 19.23 min. Under these optimized conditions, the blended coagulant achieves remarkable removal efficiencies, approximately 99.99% for color and 98.7% for turbidity. These findings underscore the efficiency of natural coagulants, particularly in blended form, for sustainable wastewater treatment in wet coffee processing.

Review on Moringa oleifera, a green adsorbent for contaminants removal: characterization, prediction, modelling and optimization using Response Surface Methodology (RSM) and Artificial Neural Network (ANN)

Moringa oleifera utilization in water treatment to eliminate emerging pollutants such as heavy metal ions, pesticides, pharmaceuticals, and pigments has been extensively evaluated. The efficacy of Moringa oleifera biosorbent has been investigated in diverse research work using various techniques, including its adsorption capacity kinetic, thermodynamic evaluation, adsorbent modifications, and mechanism behind the adsorption process. The Langmuir isotherm provided the most remarkable experimental data fit for batch adsorption investigations, whereas the best fit was obtained with the pseudo-second order kinetic model. Furthermore, only a few papers that combined batch adsorption with fixed-bed column investigations were examined. In the latter articles, the scientists modified the adsorbent to increase the material's adsorption capacity as determined by analytical methods, including IR spectroscopy, scanning electronic microscope (SEM), and X-ray diffraction (XRD). However, the raw material can show appreciable adsorption capacity values, proving moringa's potency as a biosorbent. Hydrogen bonds, electrostatic interaction, and van der Waals forces were the main processes in the found and reported adsorbent-adsorbate interactions. These mechanisms could change depending on the physiochemical nature of adsorption. Although frequently employed for heavy metal ions and dye adsorption, Moringa oleifera can still be explored in pesticide and medication adsorption investigations due to the few publications in this comprehensive review. This study, therefore, examined different Adsorbents from the Moringa oleifera plant, as well as parameters and models for enhancing the adsorption process.

Removal of manganese from wastewater using Moringa stenopetala plant parts as an adsorbent material

Removal of heavy metal ions from industrial effluents using environmental friendly bioadsorbents is currently promising approach. However, removal of manganese metal ion via Moringa stenopetala (M.stenopetala) plant material is not studied yet. Thus, parts of the plant has been studied as bio adsorbents for removing toxic manganese ion from aqueous solutions in batch adsorption model. The maximum percent removal of manganese ion obtained from laboratory synthetic wastewater at equilibrium are 96.05 %, 98.90 % and 97.93 % by M. stenopetala plant leaf, bark and seed, respectively. However, the use of M. stenopetala plant leaf procedures an intensive color with unpleasant odor, which is inauspicious. Therefore, M. stenopental plant leaf was no longer examined for isotherm and kinetics studies. The fitness of adsorption data were confirmed based on the value of correlation coefficient (R2). Thus, adsorption by bark best fits of Temkin model with R2 value of 0.9707, while adsorption by seed follows the Langmuir model with R2 value of 0.9733. Adsorption kinetics result indicates that pseudo second-order model well fitted with R2 value of 0.9912 and 0.9947 for bark and seed adsorbents, respectively. Additionally, the applicability of laboratory-developed method was also evaluated on a multicomponent real sample taken from KK textile industry from Addis Abeba, Ethiopia. After characterization, the percentage removal of manganese ion were 79.53 % and 88.93 % for bark and seed, respectively. This achievement is promising and in a good agreement with the results of single component laboratory synthetic wastes.

Moringa oleifera: a valuable insight into recent advances in medicinal uses and pharmacological activities

Moringa oleifera is an important medicinal plant in several countries; for example, Nigeria, the USA, Turkey, Germany, Greece, and Ukraine. The abundant bioactive and nutritional properties of this plant make it useful in many and diverse areas of life, including the health, cosmetic, agricultural, and food industries to mention but a few. Research has found that the presence of proteins, carbohydrates, lipids, vitamins, minerals, flavonoids, phenols, alkaloids, fatty acids, saponins, essential oils, folate, aromatic hydrocarbons, sterols, glucosinolates, and glycosides, among others, characterize the moringa nutrient profile and, as a result, give rise to its remedial effects on ailments such as wounds, stomach and duodenal ulcers, allergies, obesity, diabetes, inflammation, asthma, and so on. It is the aim of this review to provide an insight into such medicinal and pharmacological remedies attributed to moringa, stating both the past and recent discoveries. This review article also takes a look into the botanical features, bioactive compounds, antinutrients, food applications, bacterial fermentation products, biosafety, industrial applications, and other uses of moringa. Finally, with the belief that knowledge is progressive, we acknowledge that there are things yet undiscovered about this wonder plant that will be of value both to medicine and general life; we therefore recommend that research work continues on the moringa plant. © 2023 Society of Chemical Industry.

Investigation on the removal of contaminants from washing machine discharge using Strychnos potatorum (clearing nut) - A potential purifying agent

The objective of the present study is to develop eco-friendly purifying agents from natural materials, Strychnos potatorum (SP) - a coagulant. The seeds of SP were used for wastewater treatment (washing machine effluent). Physico-chemical parameters like turbidity, total dissolved solids (TDS), electrical conductivity (EC), pH, calcium (Ca2+), magnesium (Mg2+) and phosphate (PO43-) were tested and the data obtained were compared with BIS standards. In the current work, physical and chemical parameters have been examined to determine the quality of water for washing machine discharge, before and after treatment (coagulation) using SP seeds. The testing procedure was carried out using a Jar test of coagulant mass 1000 mg/L with rapid mixing at 150 rpm for 5 min, slow mixing at 30 rpm for 25 min and a settling period of 1 h. Coagulation results were reported for the use of SP seeds, where the effectiveness of removing turbidity and PO43- was determined to be 81.54 and 41.45%. The presence of various functional groups in SP seed was assessed by fourier transform infrared (FT-IR) spectroscopy. Qualitative identification of phytochemical constituents of seed extract for this species was also carried out. The experimental findings strongly highlighted the ability of SP seeds to remove turbidity and PO43- from wastewater.

Assessment of Drinking Water Quality in Urban Water Supply Systems: The Case of Hawassa City, Ethiopia

In many developing countries, such as Ethiopia, water quality and the risk of water-related diseases are serious public health issues. The present study goal was to assess the drinking water quality from source to household tap water. To characterize and analyze drinking water quality parameters, 21 water samples were collected, of which 11 water samples were collected from sources (spring, borehole, and river), 4 from service reservoirs, and 6 from tap water. The mean values of the parameters were as follows: total dissolved solids (TDS) (142.79 mg/L), temperature (22.08°C), turbidity (9.49 NTU), electrical conductivity (EC) (250.14°μS/cm), pH (7.45 mg/L), fluoride (1.15 mg/L), nitrate (NO3-) (2.91 mg/L), total hardness (TH) (57.45 mg/L), calcium (41.7 6 mg/l), magnesium (10.74 mg/L), phosphate (0.44 mg/L), sulfate (3.99 mg/L), residual chlorine (1.53 mg/L), alkalinity (196.39 mg/L), and microbiological (total coliform and coliform/CFU) which were the main physiochemical parameters analyzed for the study. The findings revealed that the majority of the water quality parameters tested were within the WHO and National Drinking Water Quality Standards (NDWQS). However, some of the parameters such as temperature, turbidity, fluoride, and residual chlorine did not meet the standards. The mean temperatures at the source, reservoir, and tap water were 22.01°C 22.5°C,and 21.83°C, respectively. Turbidity levels in source samples ranged from 10 to 45 NTU, with a mean of 24.5 NTU, exceeding the WHO's recommendation of less than 5 NTU. The Boko Alamura well had a high fluoride content (3.9 mg/l), which was above the WHO and NDWQS permissible limits. There was no free residual chlorine in the tap water sample. The results show that the Hawassa drinking water supply did not contain total or fecal coliform in any of the samples tested. The overall WQI for the water source, reservoir, and tap water was also determined to be 89, 71, and 69.7 points, respectively. Therefore, based on the WQI result, Hawassa drinking water quality is good for the source, reservoir, and tap water.

A comparative study on polyaluminum chloride (PACl) and Moringa oleifera (MO) chemically enhanced primary treatment (CEPT) in enhanced biogas production: anaerobic digestion performance and the Gompertz model

A comparative study was performed to estimate biogas production from sludge produced by organic and inorganic chemically enhanced primary treatments (CEPTs). To this end, the effects of two coagulants, polyaluminum chloride (PACl) and Moringa oleifera (MO), on CEPT and biogas production in anaerobic digestion were surveyed within an incubation period of 24 days. The optimal dosage and pH of PACl and MO were optimized in terms of sCOD, TSS and VS parameters in the CEPT process. Next, the digestion performance of anaerobic digestion reactors fed with sludge obtained from PACl and MO coagulants at a batch mesophilic reactor (37 ± 1 °C) was surveyed from the biogas production, volatile solid reduction (VSR) and Gompertz model. At the optimal conditions (pH = 7 and dosage = 5 mg L^-1), the removal efficiency of COD, TSS and VS in CEPT assisted with PACL was 63, 81 and 56%, respectively. Moreover, CEPT assisted with MO led to the removal efficiency of COD, TSS and VS until 55, 68 and 25%, respectively. The highest methane yield (0.598 L g_{VS removed}^-1) was obtained in an anaerobic digestion reactor with sludge from the MO coagulant. The anaerobic digestion of CEPT sludge instead of primary sludge resulted in higher sCOD removal efficiency, and 43-50% of sCOD was observed compared with the removal of 32% for the primary sludge. Furthermore, the high coefficient of determination (R²) demonstrated the trustworthy predictive precision of the modified Gompertz model with actual data. The combination of CEPT and anaerobic digestion, especially using natural coagulants, provides a cost-effective and practical way to increase BMP from primary sludge.

Coagulation-flocculation treatment for batik effluent as a baseline study for the upcoming application of green coagulants/flocculants towards sustainable batik industry

The batik industry has been one of the main family businesses in most of the east-coast region of the Malaysian peninsula for many years. However, appropriate water treatment is still a major challenge for this industry. Stringent laws introduced by the Malaysian authorities and the intention to protect the environment are factors that drive researchers to search for suitable, appropriate, affordable and efficient treatment of batik wastewater. Treatment research on batik wastewater is still lacking and coagulation-flocculation treatment using alum was introduced and chosen as a stepping stone toward the selection of green coagulants. This study aimed to determine the best conditions for alum flocculation-coagulation using a standard jar test method. Four main factors were investigated: alum dosage (0.1-3.5 g/L), pH (4-11), settling time (0.5-24 h) and rapid mixing rate (100-300 rpm). Results obtained were further analysed statistically using SPSS software prior to determining the significant effect of variable changes. From this study, the best conditions for batik wastewater treatment using the flocculation-coagulation process were found to be at alum dosage of 1.5 g/L, pH 8, 4 h settling time and a rapid mixing rate of 100 rpm. Chemical oxygen demand (COD), turbidity, colour and total suspended solids (TSS) were removed by 70.7, 92.2, 88.4 and 100%, respectively, under these conditions. This study showed that batik wastewater can be treated by the coagulation-flocculation process using chemical means of alum. This indicates the need for forthcoming developments in natural-based-coagulant-flocculants toward the sustainability of the batik industry.

Water Treatment Using Natural Coagulant and Electrocoagulation Process: A Comparison Study

Water treatment is the primary consideration before utilizing water for different purposes. Surface water is highly vulnerable to pollution, either due to natural or anthropogenic processes. The main targets of this study were to investigate surface water treatment using Moringa Oleifera (MO), the electrocoagulation process (EC), and the Moringa Oleifera assisted electrocoagulation process (MOAEC). The Moringa Oleifera, EC process, and Moringa Oleifera-assisted EC process are effective mechanisms for the removal of COD (Chemical Oxygen Demand), BOD (Biological Oxygen Demand), TDS (Total Dissolved Solids), phosphate, TSS (Total Suspended Solids), and color from surface water. Different operating parameters such as pH (5–11), the dosage of coagulant (0.2–0.5 g), contact time or reaction time (20–50 minutes), current (0.2–0.5 A), and settling time (5–20 minutes) were considered. The maximum removal efficiency using Moringa Oleifera and the EC process was COD (85.48%), BOD (78.50%), TDS (84.5%), phosphate (95.70%), TSS (93.90%), color (94.50%), and COD (90.50%), BOD (87%), TDS (97.50%), phosphate (89.10%), TSS (95.80%), and color (96.15%), respectively. Similarly, with the application of MOAEC, 91.47%, 89.35%, 97.0%, 90.20%, 9.10%, and 95.70% of COD, BOD, TDS, phosphate, TSS, and color were removed, respectively. The EC process and MOAEC were more effective in the removal of COD, BOD, TDS, TSS, and color than using MO. More phosphate was removed using MO than the EC process and MOAEC. Additionally, the effects of different operating parameters were studied on the removal efficiency.

Fate of antibiotic resistant genes in wastewater environments and treatment strategies - A review

Antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) have emerged in aquatic environments through the discharge of large amounts of antibiotics into wastewater. Well-designed wastewater treatment plants (WWTPs) with effective treatment processes are essential to prevent the release of ARGs directly into the environment. Although some systematic sequential treatment methods are used to remove ARGs, considerable gaps in removal mechanisms will be discussed. Therefore, deep analysis and discussion of various treatment methods are required to understand the ARGs removal mechanisms. In this manuscript, the role of antibiotics and the resistance mechanism of ARB are discussed in depth. In addition, the fate of ARGs in an aquatic environment and detection methods are compared comprehensively and discussed. In particular, the advantages and disadvantages of various methods are summarized and reviewed critically. Finally, combined technologies, such as advanced oxidation process (AOP) with biochemical systems, membrane separation with electrochemical AOP, ultrafiltration (UF) membrane coupled with photocatalytic treatment, and UF membrane separation coupled with sonication, are introduced. Overall, low-energy anaerobic treatment reactors with any of the above combined treatments might reduce the discharge of large quantities of ARGs into the environment. Finally, this review provides valuable insights for better ARG removal technologies by introducing combined effective treatment strategies used in real WWTPs.