Utilization of Coffee Grounds and Fly Ash as Adsorbents to Reduce Phosphate Content in Laundry Wastewater

Industrial laundry wastewater contains 70-80% phosphate which can cause environmental pollution and trigger the growth of algae blooms or eutrophication if it is discharged into the environment. The adsorption method was chosen to reduce the phosphate content in laundry waste because it is relatively simple and low cost. The adsorbent used can use coffee grounds and fly ash, where coffee grounds have 47.8-58.9%. The composition used for the adsorption process is a ratio of coffee grounds: fly ash (w/w) of 1:0 and 1:1. Contact time in the adsorption process varies between 30 minutes, 60 minutes, 90 minutes, 120 minutes, 150 minutes. Based on research results, the best reduction in phosphate levels from laundry waste was 45.88%, where the initial phosphate level in the waste was 10.2 mg/L. Apart from that, the efficiency of reducing COD levels with the best removal efficiency was 80.39% with the initial COD content in the waste being 4080 mg/L. The best composition for testing laundry waste is 1:1 coffee grounds and fly ash (w/w) and the best contact time for testing laundry waste is 150 minutes.