Tropical Aquatic and Soil Pollution

Synergistic Effect of Banana Corm-Based Microbial Organic Liquid and Cyperus papyrus on Lead Removal in a Subsurface Flow Constructed Wetland System

2026-05-02T02:32:54+00:00

Laboratory wastewater often contains hazardous heavy metals such as lead (Pb). A previous study found that laboratory wastewater contained Pb at a concentration of 3.52 mg/l, exceeding the Indonesian quality standard (1 mg/l; Minister of Environment Regulation No. 5/2014). In that study, laboratory wastewater was treated using a subsurface flow constructed wetland (SSF-CW) with Cyperus papyrus, which successfully reduced Pb concentration from 3.52 mg/l to 0.75 mg/l within 9 days. While effective, this setup required a long retention time and large space. To improve treatment efficiency, this study combined Cyperus papyrus with banana corm-based microbial organic liquid (MOL) containing indigenous microorganisms. A batch SSF-CW reactor (soil and gravel media) treated 1.2 l of artificial wastewater (initial Pb concentration: 3.33 mg/l) using 10% (v/v) banana corm MOL and four Cyperus papyrus plants. Pb concentration, pH, and plant morphology were monitored for nine days. The results showed that Pb concentration met the quality standard by day 2 (0.283 mg/l; 91.50% removal) and reached maximum removal on day 4, with Pb concentration < 0.0002 mg/l and 99.99% removal efficiency. Thus, combining Cyperus papyrus with banana corm MOL proved more effective in reducing Pb concentration than using Cyperus papyrus alone, achieving comparable results in only two days instead of nine.

Optimisation of Photocatalytic Degradation for Enhancing Bathroom Greywater Quality Using 2,4,6-Trinitrotoluene/Zeolite Photocatalyst

2026-03-14T05:22:56+00:00

This experimental study investigated the solar photocatalytic degradation process for improving bathroom greywater quality using titanium dioxide nanotubes modified 2,4,6-trinitrotoluene with zeolite (TNTs/zeolite) and sought to optimize it. Organic pollutants, suspended solids, and personal care products remained in total household greywater at a proportion of 43–70% from bathroom sources. The optimization method applied was Central Composite Design (CCD) under Response Surface Methodology (RSM), in which three independent variables were considered: pH within a range of 3–10; catalyst loading expressed as the exposed surface area of 1 or 2 cm²; and irradiation time between thirty and one hundred eighty minutes under natural sunlight conditions with average irradiance values between six hundred twenty and seven hundred eighty watts per square meter. Twenty runs were carried out in triplicate. The responses tested were Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), turbidity, pH, and Dissolved Oxygen (DO). The optimum condition predicted by RSM had a pH of 6.25, an irradiation time of 180 minutes, and a catalyst loading of 1 × 1 cm². Experimental validation at this optimum condition confirmed the adequacy of the model, with removals greater than 50% for COD, BOD, TSS, and turbidity. ANOVA showed that the models were statistically significant (p < 0.0001) and highly predictively reliable (R² > 0.90 for most responses). The study demonstrated that TNTs/zeolite under natural sunlight represented a potential low-energy alternative for bathroom greywater treatment with practical possibilities for decentralized reuse applications.

Eco-Friendly Wood Preservation Using Nano Urea to Prevent Fungal Degradation and Improve Material Durability

2026-05-10T01:57:24+00:00

Wood is widely used in construction due to its renewability and favorable mechanical properties; however, it is highly susceptible to fungal degradation, which reduces durability and structural performance. Conventional wood preservatives are effective but often raise environmental and health concerns because of their toxic chemical content. This study investigates the use of nano-urea as an eco-friendly wood preservative for sengon wood (Falcataria moluccana), representing one of the first studies exploring nano-urea specifically for antifungal wood protection and durability enhancement. Sengon wood samples were treated with nano-urea at concentrations of 2%, 3%, and 5%, alongside untreated control samples. Antifungal performance was evaluated through weight loss measurements, fungal growth observations, and assessment of the infected area after 12 weeks of exposure, while mechanical performance was assessed using tensile strength testing and microstructural analysis. The results demonstrated that increasing nano-urea concentration significantly reduced fungal degradation, with the 5% treatment completely inhibiting visible fungal growth. In addition, nano-urea treatment slightly improved tensile performance and produced a denser wood microstructure with reduced pore size, indicating enhanced structural compactness. These findings confirm that nano-urea is a promising sustainable alternative to conventional preservatives, offering effective biological protection while maintaining mechanical integrity. The proposed treatment also shows strong potential for scalable and environmentally responsible applications in sustainable construction and wood-based material industries.