PERFORMANCE OF BUBBLE COLUMN BIOREACTOR TO PRODUCE LIQUID ORGANIC FERTILIZER (LOF) FROM COW URINE AND SLURRY ORGANIC WASTE

This research aimed to evaluate the effectiveness of various diffusers in a bioreactor for producing liquid organic fertilizer (LOF) using cow urine and slurry organic waste as materials. LOF was produced by treating the organic waste with Urine-Single Orifice Diffuser (USOD), Urine-Coarse Bubble Diffuser (UCBD), Urine-Fine Bubble Diffuser (UFBD), Slurry-Single Orifice Diffuser (SSOD), Slurry-Coarse Bubble Diffuser (SCBD), and Slurry-Fine Bubble Diffuser (SFBD) in a bioreactor equipped with a water pump and an external aerator unit. The pump circulated and agitated the biomass at a discharge of 10 L/min. Meanwhile, the external aerator unit pumped air into the bioreactor, which the biomass absorbed at a discharge of 45 L/min. The discharge of biomass and water also caused agitation of the fermented biomass. Several variables were observed during the fermentation process, including temperature, acidity (pH), total dissolved solids (TDS), C/N ratio, electrical conductivity (EC), biological oxygen demand (BOD), microbial population, cation exchange capacity (CEC), and other chemical properties. LOF produced had a pH, temperature, total organic matter content, EC, TDS, BOD, microbial population, and CEC values of 6.3–6.8, 28.0–37.0°C, 20.77–22.46%, 54630–62369.24 µmS, 7543–11700 ppm, 1.2–2.6 mg/L, 3.2–7.5 log CFU, 12.3–14.1, and 29.98 me/100 g, respectively. The macro and micro nutrient contents of bio-urine were 12.72–12.96%, and 3.09–3.25%. Meanwhile, those of the bio-slurry were 12.35–12.99% and 2.39–2.72%. These characteristics of LOF were in accordance with the Indonesian National Standard (SNI).