Analytic instrumentation can be used to significantly reduce energy consumption on sewage treatment plants, thereby also achieving cost savings. In all sewage treatment facilities, there are many dissolved oxygen measuring points. These points are mainly concentrated around the aeration ponds. Their function is to ensure that the dissolved oxygen level is kept constant in the aeration ponds to facilitate the complete breakdown of ammonia (NH4) to nitrate (NO3).
To achieve a correct dissolved oxygen (DO) concentration, air blowers or agitators are used. Air bubbled through the basin with the help of blowers, dissolves oxygen into the water. Agitators on the other hand, agitate the water at high speed, thus forcing oxygen to dissolve into the water. Both these methods require high-energy input, as the motors driving blowers and agitators require vast amounts of electricity. If it were possible to be able to turn these motors off for some time, immediate cost savings would be achieved.
Similarly, if it was possible to measure ammonia content in aeration basins online and have a short measuring time, it would be possible to determine when all the ammonia has been broken down, following which the aeration rate can be reduced or even stopped completely until the ammonia level rises again to a sufficient level.
The same argument is applicable to the nitrate reduction and phosphate reduction section. Instead of dosing a constant amount of coagulant and flocculant to precipitate the phosphate components, measure the phosphate content and dose accordingly. Measuring the parameter that is needed to be eliminated permits the production of higher quality effluent. Endress+Hauser's range of analysers make this functionality available.
With an E+H Stamolys analyser (Figure 1), measuring time is reduced to as little as 4 minutes. That is more than sufficient to detect and react upon any increases or decreases in the measured species. The self-cleaning, self-calibrating analyser is freely configurable and could have up to 2-hour measuring intervals. Its measuring principle is compliant to both ISO standards and EN specifications. The Stamolys works on photometry principles and uses colour specific wavelength detectors. Turbidity and sample inherent colour is actively compensated for by the unique measuring method. Calibration and cleaning intervals are freely programmable up to 72 hours.
As an alternative measuring technology, Endress+Hauser also offers nitrate measurement with ultraviolet light absorption (Figure 2). The unit does not require reagents and is comparable with laboratory procedures. The unit can be mounted directly into a high solids concentration medium without any sample preparation methods and can be cleaned with a simple spray cleaning system (that will keep the lenses clean). Active compensation for inherent colour and turbidity is a built-in function.
Endress+Hauser's analyser range also monitors iron (Fe), manganese (Mn), nitrite (NO2), aluminium (Al) and COD measurement, as well as special technical products for copper (Cu), fluoride (F-), water hardness (as CaCO3), BOD and TOC. Sample preparation systems are also available.
For more information contact Grant Joyce, Endress+Hauser, 011 262 8000, www.za.endress.com
| Tel: | +27 11 262 8000 |
| Email: | [email protected] |
| www: | www.endress.com |
| Articles: | More information and articles about Endress+Hauser South Africa |
© Technews Publishing (Pty) Ltd | All Rights Reserved
printer friendly version