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The performance of extracted coagulant from the sugarcane bagasse was tested using synthetic wastewater for turbidity removal. Sugarcane bagasse was selected because it is available in abundance as a waste. This study was carried out to analyze the effect of the extraction process in optimizing the active coagulant agent of bagasse as a natural coagulant for optimum turbidity removal. Bagasse was characterized in terms of physical, chemical and morphological properties. The results showed bagasse has very high polysaccharide content which can act as an active coagulant agent together with hemicellulose and lignin. The extraction process for degradation of lignin and hemicellulose was run based on two different solvents (NaOH and H2SO4) with varying concentrations from 2% to 10% at different extraction temperatures varied from 60 °C to 180 °C for various extraction times (0.5 h to 3 h). The optimum polysaccharide content extracted from bagasse was 697.5 mg/mL by using 2% NaOH at 120 °C for 2 h extraction. The coagulation process using extracted bagasse showed the removal of suspended solids up to 95.9% under optimum conditions. The concentration of polysaccharides as the active coagulant agent plays a vital role where high polysaccharides content removes most turbidity at a lower dosage. Bagasse has the potential to be an alternative coagulating agent due to its efficiency, and eco-friendly properties for the treatment of wastewater. [ABSTRACT FROM AUTHOR]

Wastewater recycling plays an important role in minimizing water loss. The recycled wastewater can be utilized for many purposes from irrigation to portable water supply. Numbers of wastewater treatment system have been applied in Malaysia to achieve quality in meeting the intended purpose of wastewater recycling. Although there are many studies reported on the efficiency of the treatment technologies, comparative assessments including the significant purpose until the estimation of operational expenditure for each of the treatment technologies are lacking. Therefore, this brief review aims to critically discuss each of the treatment technologies from the secondary treatments, tertiary treatments, to the advanced treatments. Based on our review, the conventional activated sludge system has high potential for wastewater recycling due to lower cost in terms of population equivalent and shows great removal efficiency among secondary treatment while sand filtration and activated carbon is the better options for tertiary and advanced treatment. Therefore, it can be concluded that conventional activated sludge system, sand filtrations and activated carbon process is the most feasible in terms of removal performance and cost effectiveness for secondary, tertiary and advanced treatments. [ABSTRACT FROM AUTHOR]

The release of silver nanoparticles (AgNPs) from consumer products into an environment has become a central issue for many countries. Despite that the fate and behaviors of AgNPs incorporated into a wastewater have been investigated by building a model of wastewater treatment process, the transport and retention behaviors of AgNPs influenced by the water flow in a river must be understood. The physical model of simulated river to mimic a natural flow of river was proposed to investigate the behaviors of AgNP transport in the river. The results showed that the large amount of AgNPs deposited on the riverbed as Ag sediment with only 1.26% of AgNPs remained in the water flow. The elemental content of Ag freely dispersed across the riverbed increases from the upstream to downstream area of the simulated river. Verification of the spatial distribution of Ag dispersed along the water flow may contribute to a better understanding of the fate and transport of AgNPs in the aquatic environment. [ABSTRACT FROM AUTHOR]

Biofiltration is a promising wastewater treatment green technology employed to remove various types of pollutants. The efficiency of biofiltration relies on biofilm, and its performance is significantly influenced by various factors such as dissolved oxygen concentration, organic loading rate, hydraulic retention time, temperature, and filter media selection. The existing biofilters utilize conventional media such as gravel, sand, anthracite, and many other composite materials. The material cost of these conventional filter materials is usually higher compared to using organic waste materials as the filter media. However, the utilization of organic materials as biofilter media has not been fully explored and their potential in terms of physicochemical properties to promote biofilm growth is lacking in the literature. Therefore, this review critically discusses the potential of shifting conventional filter media to that of organic in biofiltration wastewater treatment, focusing on filtration efficiency-influenced factors, their comparative filtration performance, advantages, and disadvantages, as well as challenges and prospective areas of organic biofilter development. [ABSTRACT FROM AUTHOR]

The degradation of organic dyes in the presence of modified TiO2 is still under intensive investigation. We report here an evaluation of the photocatalytic activity of nitrogen- (N-) and sulfur- (S-) doped TiO2 for the degradation of phenol and methylene blue (MB). N-doped TiO2 (N-TiO2), S-doped TiO2 (S-TiO2), and N-S-doped TiO2 (N-S-TiO2) were prepared using the sol-gel method. The photocatalytic activity was evaluated in a batch reactor using phenol and MB as models of pollutants. In addition, this investigation was performed using a household lamp as the visible light source. Properties of the synthesized materials in terms of Brunauer-Emmett-Teller (BET) surface analysis, field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and photocatalytic ability were examined. Our study shows that N-S-TiO2 exhibits better photocatalytic degradation ability for all the considered dyes compared to the other doped TiO2 materials. In conclusion, we have successfully prepared and evaluated the photocatalytic activity of N- and S-doped TiO2 for the degradation of phenol and MB using an ordinary household lamp. [ABSTRACT FROM AUTHOR]

Alkaliphilic cyanobacteria are suitable candidates to study the effect of alkaline wastewater cultivation on molecular metabolic responses. In the present study, the impact of wastewater, alkalinity, and alkaline wastewater cultivation was studied on the biomass production, biochemical composition, and the alkalinity responsive molecular mechanism through metabolomics. The results suggested a 1.29 to 1.44-fold higher biomass production along with improved lipid, carbohydrate, and pigment production under alkaline wastewater cultivation. The metabolomics analysis showed 1.2-fold and 5.54-fold increase in the indole-acetic acid and phytoene biosynthesis which contributed to overall enhanced cell differentiation and photo-protectiveness. Furthermore, lower levels of Ribulose-1,5-bisphosphate (RuBP), and higher levels of 2-phosphoglycerate and 3-phosphoglycerate suggested the efficient fixation of CO 2 into biomass, and storage compounds including polysaccharides, lipids, and sterols. Interestingly, except L -histidine and L -phenylalanine, all the metabolites related to protein biosynthesis were downregulated in response to wastewater and alkaline wastewater cultivation. The cells protected themselves from alkalinity and nutrient stress by improving the biosynthesis of sterols, non-toxic antioxidants, and osmo-protectants. Alkaline wastewater cultivation regulated the activation of carbon concentration mechanism (CCM), glycolysis, fatty-acid biosynthesis, and shikimate pathway. The data revealed the importance of alkaline wastewater cultivation for improved CO 2 fixation, wastewater treatment, and producing valuable bioproducts including phytoene, Lyso PC 18:0, and sterols. These metabolic pathways could be future targets of metabolic engineering for improving biomass and metabolite production. Alkalinity is an imperative factor, responsible for the contamination control and biochemical regulation in cyanobactera, especially during the wastewater cultivation. Currently, understanding of alkaline wastewater responsive molecular mechanism is lacking and most of the studies are focused on transcriptomics of model organisms for this purpose. In this study, untargeted metabolomics was employed to analyze the impact of wastewater and alkaline wastewater on the growth, CO 2 assimilation, nutrient uptake, and associated metabolic modulations of the alkaliphilic cyanobacterium Plectonema terebrans BERC10. Results unveiled that alkaline wastewater cultivation regulated the activation of carbon concentration mechanism (CCM), glycolysis, fatty-acid biosynthesis, and shikimate pathway. It indicated the feasibility of alkaline wastewater as promising low-cost media for cyanobacterium cultivation. The identified stress-responsive pathways could be future genetic targets for strain improvement. [Display omitted] • Alkalinity-responsive mechanism of Plectonema terebrans was elucidated through metabolomics • Sterol biosynthesis, carbon-nitrogen uptake, and protective mechanisms conferred stress-tolerance • Alkalinity especially favored the CO 2 sequestration, and protein biosynthesis • Synthesis of important metabolites may be enhanced by alkaline wastewater cultivation [ABSTRACT FROM AUTHOR]