Studi Pengaruh Kerapatan Tanaman Kayu Apu (Pistia Stratiotes) dalam Penurunan Konsentrasi Fosfat pada Limbah Cair Laundry

Abstract

Laundry wastewater contains phosphate derived from detergent components, particularly sodium tripolyphosphate (STPP), which may contribute to eutrophication when discharged into aquatic environments without proper treatment. Phytoremediation using Pistia stratiotes is considered an environmentally friendly and cost-effective alternative for reducing phosphate concentration in wastewater. This study aimed to analyze the effect of Pistia stratiotes plant density and laundry wastewater concentration on phosphate removal efficiency. The experiment was conducted using a batch phytoremediation system with three plant density treatments, namely a control (without plants), 15 g/L, and 30 g/L, at laundry wastewater concentrations of 20% and 40%. Observations were performed on days 0, 3, 6, 9, and 12 by measuring phosphate concentration, pH, and temperature. Phosphate concentration was analyzed using the ascorbic acid spectrophotometric method based on SNI 06-6989.31-2005. Since the data did not meet the homogeneity assumption, statistical analysis was performed using the Aligned Rank Transform Analysis of Variance (ART ANOVA). The results demonstrated that phosphate removal efficiency increased from day 3 to day 9 and declined on day 12. The highest removal efficiency of 69.27% was achieved at a plant density of 30 g/L with 20% laundry wastewater concentration, producing the lowest phosphate concentration of 0.76 mg/L. ART ANOVA indicated that plant density significantly affected phosphate removal efficiency (F = 33.040; p = 2.9892 × 10⁻¹⁰), while laundry wastewater concentration also had a significant effect (F = 15.024; p = 0.00068732). However, the interaction between plant density and wastewater concentration was not significant (F = 3.874; p = 0.06206760). Throughout the phytoremediation process, pH remained within the range of 6.79–8.62 and temperature ranged from 25.7–29.4°C, indicating environmental conditions that supported the growth of Pistia stratiotes. Overall, a plant density of 30 g/L demonstrated the highest effectiveness in reducing phosphate concentration, indicating that Pistia stratiotes has considerable potential as a simple, environmentally friendly, and low-cost phytoremediation technology for treating laundry wastewater.