The next generation nutrient analysers helping optimise wastewater treatment
Modern monitoring tools are helping wastewater treatment plant operators save money and ensure environmental discharge limits are met.
Historically, water authorities would only know what was being discharged into the environment after the fact, through on-site or lab testing. But Endress+Hauser Victorian State Manager Steve Street said today’s technology makes the monitoring process more reliable, accurate and timely.
“With the previous generation of technology, you would only know retrospectively what was being released, by measuring a collection of samples taken throughout a whole day or week,” Street said.
“There was no opportunity to control what was being discharged; the results from the testing would come in too late to change the process.
“With the latest technology you are now getting data in real time, which means you can stop the plant from discharging if you’re in breach.”
Along with ensuring the discharge is within the correct limits, tools like Endress+Hauser’s ammonium analyser can also help optimise operations and save energy.
The accuracy of the analyser – it can measure ammonium levels with 0.1mg/l accuracy – means operators can control the amount of dissolved oxygen needed in an aeration tank based on the ammonium load.
“Before, a treatment plant might only monitor dissolved oxygen and run their blowers independently of ammonium levels,” Street said.
“But when you accurately know the ammonium level you can control the process such that it is marginally below your Environment Protection Authority limit.
"For example, if the plant has a discharge limit of 1mg/l, and you’re discharging at 0.2mg/l, you’re wasting energy in aeration.”
Street said the latest generation of analysers are designed to be low maintenance, which makes them ideal for regional and remote locations.
This includes an inbuilt cooling module that keeps temperatures down even in hot locations and increases the lifetime of the reagents within them.
“Usually with reagent based analysers you would have to change the reagents every three to four weeks,” Street said.
“The maintenance on the latest analysers can be pushed out to every three months … This means you can run advanced nutrient analysis even on a regional or unmanned site.”
The technology is also getting smarter all the time with the industrial internet of things (IIoT), Street said.
This means an analyser in a remote location can send an alert for high/low measurement levels or if it is down or due for maintenance.
“As the tools get more accurate and less maintenance intensive, it’s becoming more feasible to put more analysers on outlets and discharge points,” Street said.
“At one of the treatment plants we’re working with, the end goal is for the plant to be unmanned.
“Upgrading to the latest generation of nutrient analysers provides a wide range of benefits, ranging from being able to control your process to avoid incidents to reducing both electricity and maintenance costs. These new analysers can be integrated into an IIoT solution providing further benefits.”