Wastewater treatment is a process used to convert wastewater into an effluent (outflowing of water to a receiving body of water) that can be returned to the water cycle with minimal impact on the environment or directly reused. The treatment process takes place in a wastewater treatment plant (WWTP), often referred to as a Water Resource Recovery Facility (WRRF) or a sewage treatment plant.
It is very important to keep biology of facility in good condition and respirometry is one of the main methods to determine the status and efficiency of cleaning.
Comparing the value of the specific respiration rate of the sample with the reference values (table), we can see whether the biological process is overloaded (there is too much substrate for so little biomass), operating with a good yield or, contrarily, there is evidence of toxicity symptoms. For the same wastewater, a gradual increase in the specific respiration rate is indicative of an increase in the biological activity, and vice versa.
Apart from being able to find out the health and current capacity of the activated sludge process and the toxic nature of the waste water for microorganisms through respirometry, this technique also enables us to:
- Optimize the aeration and thus encourage energy savings at the plant. By means of respirometry the real oxygen needs can be accurately determined for a waste water and with a certain biomass.
- Characterize the water to be treated according to its biodegradability due to the activated sludge. We can find out the COD fractioning of the water to be treated according to whether it is quickly biodegradable, gradually biodegradable or not biodegradable. This characterization is very useful for evaluating and adjusting the process.
- Detect industrial effluents with inhibitory or toxic effects on the biomass. Respirometry enables us to detect the harmful effects of the waste water on the microorganisms just when it is starting to affect them, enabling us to take measures to alleviate the effects caused.
- Optimize the process of nitrification/denitrification. It enables us to determine the real nitrification rate and the real denitrification rate of our process. Based on these values we can readjust the age of the sludge.
- Analyse the ratio of nutrients (C:N:P) in the waste water. The fact that the essential nutrients are not in the waste water in the proportion that the microorganisms need them causes many negative effects on the stability of the activated sludge process. Using respirometry we can detect whether the nutrient ratio in the water is reducing the biological activity and causing problems.
- Determine kinetic parameters, necessary for modelling the process. By means of respirometry we can determine parameters such as the heterotrophic biomass yield coefficient, the rate of use of the COD, the rate of nitrification, etc.
Thus, respirometry is a simple and practical technique that provides direct information on the biomass. It enables us to anticipate most of problems that can affect the process, guaranteeing that right from the start the correct measures are taken to alleviate the problem. Similarly, also it is an indispensable instrument for optimizing the process and determining essential parameters for its modelling.
Optimizing the industrial wastewater treatment plants. With the ECHO Instruments anaerobic respirometer, the paper mill can make a very fast analysis of the status and determine the efficiency of cleaning. The goal is to optimize the addition of chemicals, like flocculates or other chemicals. By controling the wastewater cleaning bioprocess using a respirometer, the companies can run the wastewater cleaning more efficiently. Respirometric measurement control enables to reduce energy, consumption of chemicals, unpleasant smell, and to produce more biogas. The advantage and benefit of an optimized wastewater cleaning process is reflected in a less burdened environment and thus in a healthier living surrounding. This also lowers the cost for the maintenance of the wastewater cleaning plant. The system can also be used in other industry fields, especially in industries, where lots of chemicals or other additives are being used in the processes.