The increasing demand for sustainable wastewater treatment has driven interest in nature-based technologies that combine biological and ecological processes. Among emerging alternatives, the hybrid phyto-biofilm reactor (HPBR) offers a promising approach for polishing domestic wastewater, particularly in removing residual ammonia and organic pollutants. In this study, a hybrid phyto-biofilm bioreactor was evaluated under varying ammonia loadings, aeration rates, and hydraulic retention times (HRTs). The system achieved 94-99 % ammonia removal and 95-99 % chemical oxygen demand (COD) removal within 24 h, demonstrating stable performance across both low and high influent concentrations. Reduced aeration prolonged the HRT required for effective ammonia removal, while COD removal remained unaffected. Kinetic modelling identified the Grau second-order model as the best fit, providing mechanistic insight into pollutant degradation. Microbial community analysis showed that dominant taxa, Aeromonas and Pseudomonas associated with simultaneous carbon utilisation and nitrogen transformation. Ammonium was oxidized to nitrate under high dissolved oxygen (DO), while lower aeration led to decreases in both ammonium and nitrate. This indicates nitrate removal under oxygen-limited conditions. The results highlight the potential of integrating phyto-biofilms as a configuration compatible with low-energy decentralised residential wastewater, promoting environmentally friendly management practices.

Petroleum is an important raw element utilised in a variety of sectors, including transportation, dyeing, cleaning, and polymers. However, its extraction, refining, and storage generate leftovers that harm the environment and present enormous waste management difficulties to the oil industry. Therefore, in order to obtain residues of crude oil in reservoirs, biological methods through microbial enhanced oil recovery (MEOR) using bacteria are essential. Biosurfactants made from ecologically benign microorganisms are employed as agents in MEOR because of their hydrophobic and hydrophilic characteristics, which make them appropriate for surfaces in a variety of situations, including water and oil. Thus, this study was carried out to cultivate and determine the morphology of Bacillus sp. and evaluate the effectiveness of the bacteria in the recovery of crude oil. Bacillus sp. bacteria are cultivated in nutrient broth for one day at 30 degrees C and subsequently using scanning electron microscope (SEM) analysis for morphological characteristics purposes. The GC-FID chromatographic analysis is used to verify the number of hydrocarbons recovered from petroleum sludge. Through SEM analysis, Bacillus sp. exposed to petroleum had a shrinkage in the cell shape. The results of GC-FID analysis revealed a potential of 91.85% long-chain hydrocarbon acquisition after the 10 days of treatment. After the 10-days, analytical data revealed that the short chain of hydrocarbons had increased in comparison to before the treatment. Overall, this work demonstrates that Bacillus sp. has the ability to extract crude oil from petroleum waste, which may subsequently be used in MEOR technology on a wider scale.

To address the inability of conventional microalgal-bacterial granular sludge (MBGS) systems to efficiently treat high-concentration chloramphenicol (CAP) wastewater, a limitation arising from the lack of specialist degrading microorganisms, this study employed bioaugmentation with Hydrogenophaga sp. This bioaugmentation strategy significantly improved system performance, elevating the average CAP removal efficiency during the light cycle to 61.3 %. The removal efficiencies of conventional pollutants (COD, NH4+-N, PO43--P) were also significantly enhanced (p < 0.01). Bioaugmentation induced substantial community restructuring, marked by increased abundances of key genera such as Rubrivivax, Sphingopyxis, and Hydrogenophaga, and strengthened metabolic synergy, confirming system adaptation to antibiotic stress via specific community succession. These microbial changes drove favorable shifts in the abundances of CAP resistance and degradation genes, thereby elevating the levels of key CAP-degrading enzymes and culminating in enhanced overall MBGS performance. This study establishes a bioaugmentation-based technical pathway for the efficient treatment of wastewater containing refractory antibiotics.

Aquaculture wastewater contains high and variable suspended solids that require rapid and efficient clarification to protect receiving waters and cultured organisms. Coagulation–flocculation using plant-based coagulants offers a sustainable alternative to metal salts; however, existing studies are largely limited to seed-derived or non–freeze-dried materials and rarely address dosage efficiency or scalability. This study evaluates freeze-dried Moringa oleifera leaf extract as a low-dosage natural biocoagulant for aquaculture wastewater treatment. Protein–polysaccharide content and functional groups were characterized to assess preservation of coagulation-active constituents following freeze-drying. Coagulation performance was evaluated using jar tests in synthetic kaolin suspension and real aquaculture wastewater, followed by statistical optimization using response surface methodology (RSM). Optimal conditions achieved 71.0

The effluent from fish farm is not toxic and can be recovered for watering plants, and nutrients recovered from sludge can be used as fertiliser. In this study, two kinds of natural coagulants (palm pith and watermelon rinds), which are alternatives to chemical coagulation, were used as eco-friendly, low-cost coagulants. Two parameters, namely, coagulant concentration and water pH, were optimised using response surface methodology (RSM) to determine the responses in terms of turbidity, total suspended solid and total dissolved solids. The optimum conditions by the central composite design (CCD) model for the maximum removal efficiency of turbidity, total suspended solids (TSS) and total dissolved solids (TDS) were obtained at the coagulant concentration of 100 mg/L and pH of 6.7 for palm pith and pH of 7.9 for watermelon rinds. The results from the RSM showed maximum removal efficiencies for turbidity, TSS and TDS were 98.8

Nutrient recovery from wastewater through biomineralisation is an alternative technology for producing struvite, a mineral containing phosphorus, nitrogen, and magnesium, which is known as a slow-release fertiliser. This approach has gained extensive attention in recent decades due to its efficiency, sustainability, and environmental friendliness compared with chemical precipitation. However, biomineralisation is a complex process involving the metabolic and enzymatic activity of microorganisms, including bacteria, fungi, and microalgae. This review describes the sources of nutrient-rich wastewater, including agriculture, food processing, and aquaculture, and discusses the mechanisms by which microorganisms such as bacteria, fungi, and microalgae facilitate nutrient recovery. The key factors influencing biomineralisation and the performance of various microorganisms under optimal conditions are analysed. This review also highlights challenges and considerations in struvite recovery, emphasising the need for continued research to enhance understanding and application. This work underscores the critical role of microorganism-mediated nutrient recovery technologies in promoting sustainable agricultural practices and mitigating environmental pollution.

Lutein is a xanthophyll carotenoid widely recognized for its roles in eye health, antioxidant and neuroprotective effects, and the prevention of oxidative stress-related disorders. The growing demand for functional foods and nutraceuticals has heightened industry interest in sustainable lutein production. However, conventional sources such as green vegetables and marigold flowers face several limitations, including low bioavailability, seasonal variability, land-intensive cultivation, and sustainability concerns. Therefore, this review provides an updated, comprehensive, and integrated overview of sustainable lutein production, extraction technologies, and functional applications. This review discusses conventional dietary sources alongside emerging alternative platforms, including microalgae, agro-industrial byproducts, and bioengineered fermentation systems. Recent advances in green extraction technologies, particularly supercritical CO2, ultrasound-assisted, and enzyme-assisted extraction, are also critically evaluated due to their potential to improve extraction efficiency while reducing environmental impact. In addition, the applications of lutein in functional foods, nutraceuticals, and pharmaceutical products are also highlighted. This review further examines key technical challenges, including low bioavailability, high production and downstream processing costs, compound instability, extraction inefficiencies, lack of standardization, and scalability limitations. Future progress will depend on integrating circular bioeconomy strategies, artificial intelligence (AI)-assisted process optimization, sustainable biorefinery concepts, and advanced stabilization technologies to support economically viable and environmentally sustainable lutein production systems.

Cultivation of microalgae in a raceway pond for anaerobic palm oil mill effluent (AnPOME) exposes the microalgae to sunlight and a larger surface area compared to a conventional ponding system. This study explored the effects of several operational factors (inoculum size, AnPOME dilution, and retention time) on AnPOME treatment using a native Scenedesmus sp. UKM9 in a raceway pond. Optimisation of these factors was also conducted to achieve the maximum removal of COD, NH4+ and PO43-. The results demonstrated that the optimal performance was achieved at an inoculum size of 10% (v/v), an AnPOME concentration of 94%, and a retention time of 18 days, with removal efficiencies of 56.8% for COD, 99.8% for NH4+, and 69.0% for PO43 -. A validation run proved the reliability of these optimal conditions, with an error of less than 10%. The findings suggested that the use of a raceway pond for AnPOME treatment using Scenedesmus sp. UKM9 offers great potential, meaning that this method might be a suitable approach for more effective and sustainable treatment of AnPOME.

Polyethylene (PE) microplastic (MPs) pollution is a growing environmental concern due to its persistence and resistance to degradation, especially in complex matrices such as landfill leachate. Conventional treatments are insufficient for complete removal, highlighting the need for sustainable alternatives. Bioaugmented phytoremediation, combining plants with functional rhizobacteria, presents a promising eco-friendly solution. This study investigates the efficiency and mechanisms of PE (MPs) remediation in leachate using Ludwigia octovalvis and its associated rhizobacteria. It focuses on modeling nutrient removal kinetics, assessing structural changes of MPs through physicochemical and spectroscopic analyses, and clarifying the synergistic role of rhizobacteria in enhancing plant performance and MPs removal. A 12-week phytoremediation experiment was performed using L. octovalvis grown in PE-contaminated leachate with and without rhizobacterial augmentation. MPs transformation was evaluated using Raman spectroscopy, field emission scanning electron microscopy with energy dispersive x-ray spectroscopy (FESEM-EDX), and high-performance liquid chromatography (HPLC), while adsorption kinetics were applied to model nutrient removal. Raman analysis indicated oxidative depolymerization of PE through C–C and C–H bond cleavage and the formation of carbonyl and hydroxyl groups. FESEM revealed significant particle fragmentation, with size reduction from 42.4–48 µm to 4.4 µm (plant only) and 2.1 µm (with rhizobacteria), indicating surface erosion. Adsorption behavior of ammonia, nitrate, and phosphate followed Elovich and intraparticle diffusion models (R 2 >0.9). HPLC showed MPs removal efficiencies of 65.7% and 73.5% for plant-only and plant–rhizobacteria systems, respectively, demonstrating enhanced transformation through synergistic plant–microbe interactions. These findings support bioaugmented phytoremediation as a promising sustainable strategy for PE remediation in leachate.

The phytoremediation technique has become a promising technology for treating various types of pollutants using plants. In this phytotoxicity study, Phragmites karka (Retz.) Trin. ex Steud., a perennial plant belonging to the family Poaceae was selected to degrade total petroleum hydrocarbons (TPH) in real petroleum sludge. Three different plant densities (five plants (P5), seven plants (P7), and nine plants (P9)) were constructed for the treatment using fifteen plastic crates, each were loaded with thirty kilograms of petroleum sludge. Each treatment was carried out in triplicate. Three crates served as plant controls (PC), while another three crate were employed as contaminant controls (CC) without a plant. Following a 28-day phytotoxicity study with a plant observation at seven-day intervals, TPH removal of 25.6%, 73.6% and 92.7% was calculated for P5, P7 and P9 crates, respectively. These removal efficiencies corresponded to plant-to-TPH mass ratios of 62.7, 87.8, and 112.9 mg g-1, demonstrating a positive relationship between plant density and TPH removal performance. Among the tested plant densities, the P9 treatment exhibited the highest TPH removal efficiency, suggesting that nine plants represent the optimal planting density for phytoremediation within the scope of this study.

The emergence of industrial activities has led to the generation of metal-containing wastewater. Untreated common metals such as iron (Fe) and aluminum (Al) may pollute the environment and harm human health. Microbial metal bioremediation seems to be a reliable and promising green technology for Fe and Al removal. Three rhizobacteria (Bacillus cereus isolate NII, Bacillus pumilus isolate NII, and Brevibacterium sp. isolate NII), isolated from a native phytoremediator of synthetic mining wastewater, have shown a great capability to remove Fe and Al. In this biosorption study, the kinetics of Fe and Al biosorption in wastewater containing different Fe-Al concentrations (10 mg Fe L-1 + 3.33 mg Al L-1, 40 mg Fe L-1 + 13.33 mg Al L-1, and 90 mg Fe L-1 + 30 mg Al L-1) were determined. The biosorption of Fe and Al by these three rhizobacteria at all concentrations was mainly dominated by the pseudo-second order model, except for Brevibacterium sp. isolate NII at 90 mg Fe L-1 + 30 mg Al L-1. These findings showed that the biosorption of Fe and Al by B. cereus isolate NII and B. pumilus isolate NII are influenced by a chemical interaction between the Fe-Al content and active sites on the cell surface of rhizobacteria. For Brevibacterium sp. isolate NII at 90 Fe mg L-1 + 30 mg Al L-1, the intraparticle diffusion kinetic model best fits the biosorption of Fe and Al; this model assumes that the biosorption can be affected by the boundary layer effect.

The rapid development of the residential and industrial sectors produces a huge amount of treated domestic wastewater. The treated wastewater is discharged and could affect the environment in the long term. Improving the quality of treated domestic wastewater for water reclamation would benefit both sectors. This study aims to determine the efficiency of the biofilm-phytoremediation integration process in reclaiming domestic wastewater. A cuboid-shaped reactor was filled with 15 L of domestic wastewater, utilizing water hyacinth and a polyethylene carrier as supporting media for the process. The integrated reactor is tested in two phases: the initial adaptation of bacteria with domestic and synthetic wastewater (Phase I) and the integration process of biofilm-phytoremediation, based on the factors of NH3-N concentration and hydraulic retention time (HRT), for 24 to 48 h (Phase II). In Phase II, pollutant removal was observed at varying NH3-N concentrations: C1 (11–13 mg/L), C2 (9–11 mg/L), and C3 (3–5 mg/L). The study’s findings indicate a consistent performance in the first phase, with removal rates for COD and NH3-N ranging between 86.7–100.0% and 79.0–99.6%, respectively. The reactor effectively removed pollutants at varying concentrations of NH3-N, with average removal up to 100% (COD), 99% (NH3-N), and 80% (PO43−). This integrated reactor shows the finest treated water quality outcomes for non-potable water recovery, as well as offers an alternative to resolve water scarcity for use in various sectors.

The increasing demand for ingredients like soybeans and corn for chicken feed can lead to higher global prices. Malaysia possesses abundance of agricultural biomass waste namely peanut shells, palm kernel cake, banana peels, and coconut husks, which remains largely untapped. This study aims to produce chicken feed from four types of biomass waste: coconut husks, soybean waste, banana peels, and palm kernel expeller, using four different waste ratios. Nutrient analysis were conducted on the produced chicken feed to determine protein, fiber, ash, moisture, fat, carbohydrate, and energy content. Subsequently, the four mixtures was compared to determine the optimal composition. Analysis shows notable differences from theoretical values; mixture A had the lowest ash (4.5g), D had the highest ash and moisture (5.4g and 9.3g), B had the lowest protein (12.5g), C had the highest protein (17.4g), thus the most balanced option for chicken feed from biomass wastes. FTIR analysis was performed to identify and characterize unknown substances in the produced chicken feed. The production of chicken feed on an industrial scale (production rate of 70 tons per day), was also studied. Economic analysis in this study shows, the estimated price for produced chicken feed was RM 435 per ton, with an IRR percentage of 28.26%, and a payback period for the factory of 3.97 years. The determined price of chicken feed was lower compared to the market price (RM 2100 to RM 4000 per ton). Therefore, biomass waste could be utilized as an alternative ingredient in chicken feed production.

The hybridizing water hyacinth (WH) with a moving bed biofilm reactor (MBBR) offers a nature-based polishing strategy, in which aeration plays a key role in determining oxygen availability, biofilm stability, and pollutants removal performance. Aeration is critical part to MBBR performance, however operational guidelines for plant-biofilm hybrids remain insufficiently underdeveloped. This study investigates the effects of aeration on NH3-N and COD removal performance that sustains the integration of macrophytes and biofilms. A two-phase laboratory scale study was conducted using WH-MBBR hybrid system to treat domestic wastewater. Phase I was operated without aeration, while Phase II was operated with continuous aeration at 2.5 L min-1 with 72 h performance monitoring. The results showed that NH3-N removal achieved 88 % at 72 h without aeration, whereas with aeration it reached 95-99 %. In addition, COD was completely removed within 28 h under aerated conditions, indicating accelerated reaction rates and improved effluent quality. Aeration is the primary factor influencing WH-MBBR polishing. Continuous low-intensity aeration enables near-complete nitrogen and organic pollutant removal. These findings provide a comparative assessment that demonstrates the role of aeration in macrophyte-MBBR performance, supporting design standards and the selection of appropriate DO range for polishing.

The characteristics and yield of biosurfactants vary significantly depending on the microbial strain and its origin. Therefore, exploring diverse microbial sources is essential to identify strains with high biosurfactant-producing potential. This study aims to optimize the mixed-culture conditions for biosurfactant production by Bacillus sp. SB1, Bacillus sp. SB3, and Lysinibacillus sp. SB6, three newly isolated strains from the roots of Scirpus grossus growing in crude oil-contaminated soil. Growth parameters were initially assessed and then optimized to enhance biosurfactant yield. Results showed that ammonium sulfate and peptone were the most effective nitrogen source combination for promoting biosurfactant production and reducing surface tension. The optimized culture medium comprising 7.6 % lubricant oil (x1), 7 g/L ammonium sulfate (x2), and 2 g/L peptone (x3) achieved a high desirability of 0.975, yielding 2.23 g/L biosurfactant and reducing surface tension to 35.52 mN/ m. Evaluation of the effect of salinity revealed that 7 g/L NaCl concentration resulted in the highest biosurfactant yield of 1.3 g/L and the minimum surface tension of 31.97 mN/m. The extracted biosurfactants were partially purified and chemically characterized. Fourier transform infrared spectroscopy and liquid chromatography-mass spectrometry confirmed the presence of lipopeptide compounds. This study highlights the potential of mixed rhizobacterial strains from oil-contaminated plant roots as a valuable source for efficient biosurfactant production.

Abundant agricultural waste can be used as poultry feed livestock because it contains a variety of macronutrients, micronutrients, vitamins, and minerals. This review paper aims to study the potential of agricultural waste for poultry feedstuffs. This review was constructed to analyze findings from previous research by collecting data from SCOPUS database. Agricultural waste contains different protein compositions in the range of 7–30

Microplastics (MP) have emerged as persistent pollutants in aquatic environments, often coexisting with other contaminants in domestic wastewater. Conventional coagulants such as alum are effective but present environmental drawbacks, including harmful sludge generation. This study investigates soybean pulp extract (SPE), a plant-based and protein-rich byproduct of soymilk production, as a natural coagulant for MP removal from municipal wastewater. SPE was prepared using ethanol extraction with and without sodium chloride (NaCl) supplementation, and its protein content, zeta potential, and coagulation performance were evaluated. Jar tests were conducted with varying SPE and alum dosages (10–50 mg/L) in wastewater spiked with 500 mg/L polyethylene (PE) microplastics. The concentration of microplastics used was higher than that normally found in domestic wastewater, and exposure to this concentration was lethal to microorganisms. Results showed that ethanol extraction alone was sufficient for protein recovery, while NaCl addition offered no significant advantage and introduced further negative charge to the extract. The optimum SPE dosage was identified at 30 mg/L, achieving 557.67± 50 mg/L of floc sediments, comparable to alum at the same dosage. FTIR confirmed the removal of PE microplastics, with peaks observed at 2915–2917 cm–¹. SPE achieved up to 96.22% turbidity removal and 59.58% total suspended solids (TSS) removal, which is nearly comparable to alum, although alum was more effective at lower dosages. These findings demonstrate the potential of SPE as an eco-friendly alternative coagulant, capable of microplastic and pollutant removal under real wastewater conditions.

Addressing the impacts of diverse carbon sources on microalgal-bacterial granular sludge (MBGS) systems is crucial for advancing this promising carbon-neutral wastewater treatment technology. This study investigates the effects of methanol, glycerol, acetate, and glucose as carbon sources on the removal efficiencies of chemical oxygen demand (COD), NH4+ -N, and PO4 3--P in MBGS systems. The findings demonstrate that carbon source type significantly influences microbial community structure and metabolic function. Acetate achieved maximum removal efficiencies of 88.5 % for COD and 75.5 % for NH4+-N by fostering an alkaline environment and promoting elevated dissolved oxygen levels, thereby enhancing key microbial processes. Glycerol enabled 94.8 % PO43--P removal by enriching Actinobacteria, which drove propionate production to support phosphorusaccumulating organisms via critical enzymes such as glycerol dehydrogenase. In contrast, methanol led to chlorophyll degradation, dominated by methylotrophic bacteria and the accumulation of acidic byproducts, which limited its treatment efficiency. This study provides critical mechanistic insights for optimizing carbon source selection to enhance pollutant removal in MBGS applications.

Biocarriers, pivotal in fostering microbial attachment during wastewater treatment, are a subject of increasing interest. This review investigates the efficacy of polyvinyl alcohol (PVA) as a biocarrier in wastewater treatment, with a particular focus on biofilm-based reactors. By consolidating existing literature, the review aims to elucidate the current stage of knowledge regarding the potential of PVA as biocarriers in biofilm-based reactors for wastewater treatment. This is achieved through a comprehensive search using multiple keywords, including “biocarrier polyvinyl alcohol gel”, “effectiveness of PVA biocarrier”, “biofilm-based reactor”, “microalgal biofilms”, “attached growth biofilm system”, “immobilisation of bacteria”, and “wastewater treatment” across various academic database. Furthermore, by scrutinising the impact of operating parameters on biofilm reactors utilizing PVA biocarriers and analysing the microbial communities thriving on PVA biocarriers through a critical review, this study uncovers novel insights and perspectives. Additionally, the review discusses various types of biofilm reactors currently in use to contextualise the findings. Throughout the review, pivotal factors such as removal efficiency, organic loading rate (OLR), and hydraulic retention time (HRT) are meticulously monitored over time to fulfil the objectives. Moreover, the review identifies and discusses the species comprising the microbial communities inhabiting PVA biocarriers. The insights garnered from this comprehensive review not only serve as a foundational basis for further exploration into the utilisation of PVA in biofilm-based reactor for wastewater treatment but also contribute substantially to the advancement of knowledge in wastewater treatment approaches.

Recovery of nitrogen from domestic wastewater through struvite precipitation enables the circular economy with revenue generation to treatment plants. Struvite formation factors (pH, magnesium mass, and reagent type) were investigated in the present study. Struvite is formed via a reaction involving NH4+-N, Mg, and P. Magnesium sources (MgCl2, MgSO4, MgO), pH (5-11), and magnesium mass (0.5-1.25 g) were identified using response surface methodology (RSM). The optimal condition was pH 8.53 with 1.13 g MgO, resulting in 97.0 % NH3-N removal and 2.66 g struvite production. The quality of struvite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), indicating an irregular rod-shaped morphology, 12.2 nm crystalline size, and 98.9 % crystallinity. The findings highlight the necessity to enhance nitrogen recovery efficiency for large-scale wastewater treatment considering the future potential of struvite.