When discharged into the environment, organic matter in wastewater will decompose, depleting the oxygen source in the water, affecting aquatic life, affecting the landscape, causing ecological imbalance. Therefore, applying appropriate technology to treat organic-rich wastewater is a very important and urgent issue. One of the biological treatment technologies that has been and is being applied is the moving bed biofilm reactorsystem (MBBR) with a moving carrying material with a adhered microorganisms to the surface (biofilm) to create favorable conditions for anaerobic microorganisms to grow and decompose organic matter in wastewater. This study evaluated the effectiveness of decomposing organic matter of actual piggerywastewater based on total COD and dissolved COD of a laboratory-scale anaerobic MBBR system with 3 input loading rates: 2.0
4.0 and 6.0 gCOD/L.day. The results showed that the decomposition efficiency of organic matter reached the highest of about 80 and 60% for CODt and CODht, respectively. The removal efficiency of TSS was quite high, reaching 84-90%. However, there was no clear correlation between organic matter decomposition efficiency and TSS type especially at high loading rates. The density of microorganisms in the reaction system increased significantly with high density and mainly (90-92.5%) were adhered microorganisms in biofilm.