Integrating phytoremediation and mycoremediation with biosurfactant-producing fungi for hydrocarbon removal and the potential production of secondary resources.

Treatment of petroleum-contaminated soil to a less toxic medium via physical and chemical treatment is too costly and requires posttreatment. This review focuses on the employment of phytoremediation and mycoremediation technologies in cleaning hydrocarbon-contaminated soil which is currently rare. It is considered environmentally beneficial and possibly cost-effective as it implements the synergistic interaction between plants and biosurfactant producing mycorrhiza to degrade hydrocarbon contaminants. This review also covers possible sources of hydrocarbon pollution in water and soil, toxicity effects, and current technologies for hydrocarbon removal and degradation. In addition to these problems, this review also discusses the challenges and opportunities of transforming the resultant treated sludge and treating plants into potential by-products for a higher quality of life for future generations.

Plant-based coagulants/flocculants: characteristics, mechanisms, and possible utilization in treating aquaculture effluent and benefiting from the recovered nutrients.

The increasing intensification of the aquaculture industry requires the development of new strategies to reduce the negative impacts of wastewater on the environment. Plant-based coagulants/flocculants, regarded as one of the environmentally friendly technologies for wastewater treatment, show good performance in the removal of suspended solids from wastewater. The aforementioned technology involves the utilization of plants as coagulants/flocculants in the treatment process and produces nontoxic sludge as treatment by-products. The produced sludge could be converted into valuable compounds used in agriculture. This review summarizes coagulation-flocculation by using plant-based coagulants/flocculants, its mechanisms, operational factors that control the treatment process, and its application in the treatment of wastewater, especially aquaculture effluent. Moreover, this work discusses the potential utilization of aquaculture sludge as a valuable compound used in agriculture. The presented review aims to emphasize the potential of using plant-based coagulants/flocculants in the treatment of aquaculture effluent and explore the potential of using the produced sludge as fertilizer for plants to solve problems related to sludge handling and the toxicity of inorganic coagulants in a recirculating aquaculture system. This paper concluded that utilization of recovered nutrients in the form of solids is feasible for agricultural purposes, while a hydroponic system can be used to reclaim the nutrients in the form of solution.

Competence of Lepironia articulata in eradicating chemical oxygen demand and ammoniacal nitrogen in coffee processing mill effluent and its potential as green straw.

Phytoremediation is an environmentally friendly technique in wastewater treatment because of its sustainability, cost-effectiveness, and simplicity. This study was conducted to examine the feasibility of use of Lepironia articulata, a potential phytoremediation plant that is native to Malaysia, in remediating coffee processing mill effluent (CPME). The aim was to determine effluent concentration or contaminant load that the plant can resist, while simultaneously results in the good removal of pollutants during phytoremediation. Four brushes of L. articulata were planted individually in a pail/reactor (mentioned as reactor afterward) containing 3 kg of sand and exposed to five different concentrations of CPME (0%, 30%, 50%, 75%, and 100%). The initial chemical oxygen demand (COD) values were 510, 3100, 4200, 7290, and 8470 mg/L, respectively, and ammoniacal nitrogen (AN) concentrations were 26, 128, 225, 376, and 509 mg/L, respectively. The height, appearance, and efficiency in removing COD and AN of each plant was observed throughout the 35-day exposure period. Results showed that plants exposed to 75% CPME demonstrated better growth than those exposed to other concentrations and exhibited the highest COD and AN removal rates (85.0% and 84.0%, respectively), providing evidence that L. articulata can be used as a phytoremediation agent of CPME with an initial COD concentration of 7290 mg/L and AN concentration of 376 mg/L. This study highlights its support to the Sustainable Development Goals adopted by the United Nations, particularly the reclamation of plant biomass used as a treatment agent and conversion into biodegradable straws. Moreover, this study adds an attractive additional point of transforming waste into resource with the proposed wastewater treatment technology.

Macrophytes as wastewater treatment agents: Nutrient uptake and potential of produced biomass utilization toward circular economy initiatives.

Macrophytes have been widely used as agents in wastewater treatment. The involvement of plants in wastewater treatment cannot be separated from wetland utilization. As one of the green technologies in wastewater treatment plants, wetland exhibits a great performance, especially in removing nutrients from wastewater before the final discharge. It involves the use of plants and consequently produces plant biomasses as treatment byproducts. The produced plant biomasses can be utilized or converted into several valuable compounds, but related information is still limited and scattered. This review summarizes wastewater's nutrient content (macro and micronutrient) that can support plant growth and the performance of constructed wetland (CW) in performing nutrient uptake by using macrophytes as treatment agents. This paper further discusses the potential of the utilization of the produced plant biomasses as bioenergy production materials, including bioethanol, biohydrogen, biogas, and biodiesel. This paper also highlights the conversion of plant biomasses into animal feed, biochar, adsorbent, and fertilizer, which may support clean production and circular economy efforts. The presented review aims to emphasize and explore the utilization of plant biomasses and their conversion into valuable products, which may solve problems related to plant biomass handling during the adoption of CW in wastewater treatment plants.

Dual function of Lemna minor and Azolla pinnata as phytoremediator for Palm Oil Mill Effluent and as feedstock.

In this study, two native duckweeds (Lemna minor and Azolla pinnata) were cultivated in Palm Oil Mill Effluent (POME) to extract nutrients from the effluent. Five grams of A. pinnata and 2 g of L. minor were transferred to 2 L POME (Initial concentrations: 198 mg/L COD, 4.3 mg/L nitrates, pH 9.53, 4 mg/L phosphate, 2.98 mg/L ammonia) with four different dilutions (2.5%, 5%, 10%, 15%) under greenhouse conditions. Samples of POME were taken every two days up to 10 days. Growth parameter, phosphate, ammonia, nitrates, pH, and COD were monitored within 10 days to select the most suitable growth medium for both plants. Results showed that 2.5% POME dilution had positive effect on L. minor growth and A. pinnata (wet weight increased by 8.7 g and 9.8 g, respectively), with all plants able to survive until the final day of exposure. The highest removal of ammonia was accomplished in 5% POME dilution by A. pinnata (98%) and L. minor (95.5%). The maximum phosphate removal was obtained in 10% POME dilution with 93.3% removal by A. pinnata and 86.7% by L. minor. Significant COD removal in 15% POME was obtained by L. minor (78%) and A. pinnata (66%). Both plants responded positively to the phytoremediation process, especially for A. pinnata which showed significant decreases in all parameters. The nutrient extraction by both plants from POME showed a positive effect on growth parameter, which has further promising potential to be used as animal feedstock.