Microorganisms of livestock wastewater were microscopically examined to identify bacillus types with optimal absorbance at 630 nm. Growth cuties of microorganisms at various levels of livestock wastewater (5, 10, 20, 30, 40, 50%) and different temperatures (20$^{C}$ , 37$^{C}$) were prepared to determine dilution at which microorganisms did not grow within 1 hour of inoculation, regardless of levels and temperatures. Heat treatment of livestock wastewater at 10 0$^{C}$ for 2 minutes was good enough to inhibit the growth of microorganisms at 20$^{C}$ and 37$^{C}$. A good linear relationship was obtained between levels of livestock wastewater and absorbance at 630 nm (R=98.88%) and dry cell weight (98.98%). The dry cell weight of microorganisms in livestock wastewater was 0.375 g/L.