Industry | Practical example | Piping
Stationary comprex® cleaning of a large sewage treatment plant
Cleaning of sludge pipes of the large sewage treatment plant of a European capital city
Deposit formation in a large-scale wastewater treatment plant often resulted in difficulties in plant operation. However, the cleaning process, which had previously been carried out manually, required a great deal of personnel and time. After several weeks of successful test cleaning with COMPREX®, the operator decided to install a fixed COMPREX® module.
The customer order
Problem
Sludge lines overgrown with debris
Deposit formation in wastewater treatment plants often leads to increased operating expenses. This is also the case with our customer. Within three months, the floating sludge lines leading from the primary clarifiers became so overgrown with greasy deposits that intensive cleaning was necessary.
However, this cleaning, which had previously been carried out manually, meant a high level of personnel and time expenditure on a quarterly basis. With several people, the lines had to be opened and cleaned over 4 days under difficult working conditions in order to restore the hydraulic capacity.
The innovative approach of those responsible: supplement the previous procedures with cleaning with COMPREX®.
- Floating sludge lines
- Deposit formation
- Increased effort in operating the lines
- Manual cleaning with high personnel and time requirements
First test cleaning
After an initial meeting in early 2019, it was decided to conduct a first test week with COMPREX®, supported by the use of rock salt as a solid. One month after manual cleaning, on-site test cleanings already showed high effectiveness. The deposits of one month could be largely removed.
The next batch of test cleaning – this time without rock salt addition – after two months of deposit formation was of limited effectiveness.
After the pipes had clogged up to the maximum over a period of four months, the attempt to clean them manually using COMPREX® in combination with the use of rock salt also failed to produce satisfactory results.
The interim conclusion: COMPREX® promises success with correspondingly short cleaning cycles. Already here it became apparent that cleaning would be required at least once a month, but that the costs in the form of cleaning as a service for the provision of manual cleaning would not be sustainable.
The challenge
The challenge, however, was to permanently slow down or even prevent deposit formation. This gave rise to the idea of permanently integrating a COMPREX® unit into the existing cleaning system on site. To enable shorter cleaning cycles, the operator was provided with the prototype of a stationary COMPREX® module (SCM). Different cleaning programs should be tested on different pipelines over several months and compared with each other.
- Regular cleaning should prevent or at least slow down deposit formation
- First test cleanings promising, but cleaning interval still too long
- Idea: Integrate stationary COMPREX® technology
- Provision prototype SCM for several months
Cleaning with the comprex® process
Implementation
Integration of the stationary COMPREX® module for pilot operation
Together with those responsible, it was worked out in advance at which points in the pipe network the stationary COMPREX® module could be used and firmly integrated into the cleaning sequence.
Result of comprex® cleaning
First successes after 5 weeks of pilot operation
Visible success after 5-week test operation
Effectiveness proven on the pipe cross-section
Testing of different cleaning intervals
The following figures show examples of the various line sections after 5 weeks of test operation. Various cleaning programs are stored in the COMPREX® unit, which are used for the respective assigned pipe section.
The pipelines of two other primary sedimentation tanks (East 1+2) as well as the pipeline into the discharge basin of the primary sedimentation tank East 2 were flushed weekly. For comparison, that pipe was flushed into the discharge basin of the East 1 primary clarifier every 14 days. A primary settling tank (west) was used as a reference, which was not cleaned at all during this time.
Interim results
- Cleaning interval: 7 days
- Cleaning interval: 14 days
- Without cleaning
Based on these results, it was decided to clean the lines on a weekly basis in the future. The cleaning programs set for the individual sections were checked and adapted by a HAMMANN project engineer.
Result of comprex® cleaning
Interim conclusion and recommendations
Further reduce cleaning intervals
ideally regular short cleaning
Optimization of the piping system
In the period between October and the end of December 2020, weekly preventive COMPREX® cleanings of the entire scum system of the East primary sedimentation were carried out, while West continued to run as a reference in normal operation (without interim cleaning).
Cleaning with the comprex® process
Further test cleaning with the Stationary COMPREX® Module
Floating sludge line primary clarifier east
Floating sludge line primary clarifier west
The weekly cleanings in the floating sludge pipes of the primary settling tanks east were able to sustainably reduce the grease deposits there by the end of December, while thick grease deposits now adhere in the reference pipes of the primary settling tanks west.
It was shown that with a weekly cleaning rhythm, no new layers of deposits could build up. The East lines could be kept clear for over 13 weeks. As a result, weekly cleanings with COMPREX® are sufficient to replace the feat of manual cleaning at high personnel and time cost.
Outlook for the further procedure
On the part of the customer the following boundary conditions apply:
- only one basin can be cleaned at a time in order to guarantee the full plant capacity
- the water level of the pool to be cleaned must be lowered accordingly
For this reason, the integration of a single COMPREX® unit is sufficient for cleaning the four primary settling tanks. Although the COMPREX® pulses are to be fed directly into the pipeline to be cleaned, the connection points of the floating sludge lines West and East are only 5 m apart, so that only short connecting lines have to be installed for VKB-West.
Result of comprex® cleaning
The next steps
Reconstruction of the plant (outlets, electronic control valves)
Integration of a stationary COMPREX® module into the wastewater treatment plant
Regular COMPREX® cleaning
Novel stationary Comprex® modules
The SCM series
Our novel stationary COMPREX® modules are suitable for regular cleaning of, for example, product lines, pig lines and other pipelines in your production. Regular cleaning reliably removes residues from the pipelines before deposits can form.
For more information, please refer to this product sheet:
The SCM series
The advantages of SCM at a glance
SYSTEM-INTEGRATED
WATER-SAVING
SIMPLE OPERATION
CHEMICAL-FREE
POWERFUL
Tailored
Why should you choose us?
With our comprex® process, we offer an effective, sustainable and resource-saving cleaning alternative.
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