Laundry Wastewater Treatment by Phytoremediation Utilized Polyculture System of Water Lettuce (<i>Pistia stratiotes</i> L.) and Giant Salvinia (<i>Salvinia molesta</i>)

The wastewater from laundry contains detergents with various types of substances including surfactants, builders, bleaching agents, and other additives. Phytoremediation using the water lettuce plant (Pistia stratiotes) and giant salvinia (Salvinia molesta) is an effort to mitigate pollution caused by laundry wastewater. The preliminary test involves wastewater concentrations of 0, 15, 30, 45, and 60% with 150 g of water lettuce and giant salvinia observed over a period of 4 d. Phytoremediation testing involved wastewater concentration of 15% with water lettuce and giant salvinia ratios of 100:0; 75:25; 50:50; 25:75; and 0:100 observed over a period of 15 d. The analyses are conducted by volumetric, gravimetric, and spectrophotometric methods. The optimal contact time for reducing pollutant levels is 15 d within the polyculture system consisting of 50 g of water lettuce and 100 g of giant salvinia. First-order kinetics provide suitable results in reducing COD, phosphate, and TSS in both monoculture and polyculture systems with R2 > 0.80, and rate constants k > 0.0284 ((mg/L) d). In conclusion, the polyculture system demonstrated better reduction effectiveness than the monoculture system, although the performance difference is insignificant. These results implied for better option in managing wastewater laundry activities.