Wastewater treatment plants are used all over the world to treat the vast amounts of wastewater produced each day. The major goal is to protect the general public from the health risks associated with untreated wastewater. Furthermore, wastewater treatment is required to avoid pollution of the environment. The most significant procedure at every treatment plant is biological wastewater treatment, in which living microorganisms play an important role in the decomposition of organic waste.
MLSS is an operational control parameter that must be tuned for the optimum treatment results among the system's numerous components.
What is MLSS in wastewater treatment?
The overall concentration of solids in an aeration tank is measured by Mixed Liquor Suspended Solids (MLSS) in wastewater treatment. Non-biodegradable suspended particles, organic materials, and microbes are all included. MLSS is also a combination of suspended particles and influent wastewater that serves as an indicator of the system's biomass or biology.
Techniques for MLSS Evaluation in Wastewater Treatment
In the late 1800s, a systematic approach for evaluating MLSS in wastewater treatment was developed, and it is still used today.
• The first step entails taking an MLSS grab sample and running it through the filter.
• Second, the filter should be ignited for around 15-20 minutes in a muffle furnace (550 degrees). It's done to get rid of the leftovers.
• Once the filter has cooled, the residue should be transferred to a desiccator for chilling purposes.
• Finally, weigh the residue that has accumulated on the filter.
Using MLSS to Improve Wastewater Treatment
MLSS concentrations in classic activated sludge wastewater treatment plants typically range from 1500 mg/l to 5000 mg/l. According to research, MLSS concentrations in Membrane Bioreactors (MBRs) ranging from 10,000 to 12,000 mg/l are significantly higher. However, it has been discovered that having a larger concentration of MLSS has both benefits and drawbacks. It is useful in smaller aeration tanks where the treatment level remains constant. However, as the concentration of MLSS rises, aeration efficiency may drop.
Increased MLSS also indicates nutritional shortage in the biomass, thickening sludge, and an increase in BOD loading, all of which lead to excessive solid production, high flow rates, and insufficient settling periods. Low MLSS indicates that DO concentrations are not maintained, that fewer organisms survive, that flow rate is reduced due to a reduction in microorganisms, and that stalked and free-swimming ciliates are declining.
As a result, maintaining an adequate MLSS concentration is critical for wastewater treatment plant operation. It is possible to achieve this by gaining a better understanding of the bacterial activity in the system. Different approaches can be used to test and evaluate MLSS in the wastewater treatment process. During peak flow, a daily inspection is preferable in large plants.
Counting plates and analysing ATP
Plate Counts tests are carried out in labs to examine tiny amounts of MLSS using plate count medium. It aids in the identification of microbial populations in wastewater. A luminometer that creates light during ATP reactions is used in ATP analysis to examine ATP, which is a kind of stored energy in bacteria.
It enables for the measurement of DNA from MLSS bacteria as well as specific bacteria with higher life forms such as nitrifiers and nocardia. This type of testing has the advantage of being extremely precise and quick.
Netsol Water Technologies is a major provider of sophisticated wastewater treatment solutions. Through its biological solutions, it also aids in the optimization of MLSS in wastewater treatment and increases the efficiency of the biological treatment process in wastewater treatment plants.