The costs for automated sludge preparation, wet removal or sludge incineration are mostly influenced by the effectiveness of the sludge thickening process.
Sewage sludge is inevitable within the scope of every waste water purification process, the disposal and recycling of which is one of the tasks of the plant operator. Due to strict terms and regulations, costs for preparation and disposal are considerable. In order to meet these requirements, the sludge treatment is now as importance as the actual sewage treatment.
When treating the sludge, different treatment methods are used to adapt the sludge in such a way that it has the desired structure and the required properties for processing or disposal.
After several days of thickening in the sludge tank, there are usually additional processes applied to further reduce the volume of the remaining liquid sludge so that for example a pourable consistency is reached. Usually, this part of the process is carried out using energy-intensive processes such as presses or centrifuges. In order to achieve high levels of dry matter, additional flocculants are used which influence the density and strength of the sludge, thus ensuring good dewatering.
An automatic sludge water discharge system enables effective pre-thickening already in the thickener tank. The advantages are:
Reduces the running time of presses or centrifuges
Reduces sludge transport volume and therefore its costs
In many countries new legislation is increasingly reducing the possibilities to dispose of sludge in the agricultural sector. The degree of contamination for soil-related sludge disposal is further reduced by stricter fertiliser regulations. As a consequence sludge incineration will be examined more closely.
By using the optimised pre-thickening process with the automatic sludge water discharge system
the volume of sludge that needs to be disposed is reduced
reduces the transportation volume
Efficiency in practice
In the following wastewater treatment plant in Germany, the efficiency of our automatic sludge water disposal was demonstrated in practice:
- sewage treatment plant designed to serve 34,000 people
- 900 m³ post-thickener tank fed with sludge
- TAS automatic sludge water discharge system operating with two pre-programmed starts per day
After one year the plant manager evaluated the operation of the Automatic Sludge Water Discharge System:
- the sludge thickness was increased from 2.4 % to 3.5 %
- the overall amount of sludge was reduced by 30 %
- less press procedures via a screw press were necessary
- the operating costs for the further sludge processing steps were on averadge reduced by 1,400 Euro per month