A simple and inexpensive way to check the health of the microorganisms in biological wastewater treatment plants and compost facilities. Based on the same principles as the fully automatic Arthur Respirometer, this Simplified Respirometer can perform the same respirometric tests for toxicity, treatability, nitrification/denitrification and organic load measurement. The readout is now manual, not electronic, and temperature control has been eliminated, resulting in an affordable but equally effective instrument. When 2 liters of biological culture (activated sludge or compost) are placed in the sample chamber, the respirometer immediately begins to measure the respiration rate, producing various shapes of respiration rate curves which indicate the health of the culture. Results are usually obtained in less than 20 minutes. Company provides a booklet of typical graphs, and personnel are available to assist in graphical interpretation.