AGXX® - the new bioactive contact catalyst
for decontamination of aqueous systems

Practice Results - AGXX® in the disinfection
of cooling lubricants (KSS)

AGXX® networks with 200 microns and 50 microns mesh are now in use in machinery and equipment with 200 liters to 120.000 liters of KSS .The nets are used in reactors, cartridges, modules and filter boxes at strategic positions so that the highest possible contact is achieved for KSS. The first conclusions from more than 12 months of practical testing are:

  • Long-term, continuous reduction of germination rates
  • Mycelium-forming fungi are destroyed faster than bacteria
  • Efficient antimicrobial action of AGXX® against all multi-resistant germs
  • AGXX® filters effectively dead biomass and micro particles from the KSS
  • no adverse influence on the KSS could be observed
  • no reduction of antimicrobial activity after 12 months of continuous use

Procedure of disinfection of KSS by AGXX®

Determining at regular intervals the CFU values for the KSS after installation of AGXX® we notice that AGXX® unlike biocides lowers the germination rates slowly but steadily. The two graphs shown in Figure A and B show two typical patterns of embryonic development through 10 weeks of practice.

Typical time evolution of the total number of colony-visual units [CFU total] after installation of AGXX® into a highly contaminated microbial KSS (A) and in a KSS for system after cleaning and replacement of contaminated emulsion (B).

The first case (Fig. A) shows the use of AGXX® in already highly microbial preloaded KSS. In such cases, when AGXX® is installed there should be a maximum germination rate of 106 CFU / ml. Higher germination rates usually lead to severe damage to the KSS or even to the disintegration of the emulsifier.

It turns out that after the installation of AGXX® the germination rate decreases slowly and continuously. Certain variations in the germination rates may occur occasionally.

Such fluctuations can often be directly correlated with peculiarities in the operation, such as failure of pumps, halt of production machines, additional external contamination and other similar transactions. Since AGXX® acts mainly as a contact catalyst a close continuous contact with the KSS is necessary for effective action.

The second case (Fig. B) shows the use of AGXX® after system cleaning and replacement of the emulsion. These usually are the better conditions for sustainable conservation of the KSS and maintaining the longest possible service life.

In addition to the lowering of germination rate we also observe significant shifts in the bacterial spectrum since there are germs that are killed by AGXX® in a particularly effective way. These are mainly mycel-forming fungi and rapidly dividing bacteria. Therefore we can assess rapid destruction of such specific germs right after the installation of AGXX®.

Installation of AGXX® modules and AGXX® floating frames within the KSS tank.

A = floating frame = (200 microns network)
B = filter module (50 and 200 microns network)
C = floating frame (50 microns network)

In this context it is important to realize that the total germination rate is only a very narrow criterion for the contamination of the KSS. First there is no method and no media up to now to identify all bacteria present in KSS. Secondly, different germs have very different effects on the quality of KSS. Roughly one can divide the effect of different bacteria on the KSS in three classes: negative-neutral-positive.

These findings illustrate that the real measured germination rates may be only one of many criterions for the current quality of a KSS. Therefore a thorough and systematic analysis of the overall situation is important. By such analysis we have won by now extensive new knowledge on additional criteria as well as other positive effects of AGXX® on the CL.

Critical points for contamination and multiplication of germs

Our use of AGXX® is always accompanied by a thorough system analysis. The systematic evaluation of the germination situation in all areas of different KSS plants identified four particularly critical points for contamination and multiplication of germs:

  • Filtering baskets with metal debris and biomass
  • Dead zones with deposits
  • Fleece of the band filter
  • Filter mats for the separation of oil residues

Mixtures of metal debris and dead biomass are ideal conditions for rapid multiplication of germs and contamination. An efficient removal of such charges from the system is therefore an important prerequisite for a substantial reduction of the germination rate.

Surprisingly high microbial loads were found on filter paper and filter mats. According to our analysis, even the new fabric on the rolls of the band filtering plants mostly is already significantly contaminated. A new fleece roll remains up to 12 months on the plant and constantly accumulates new germs by fluid splashes or other contact from the work environment. The germs then multiply and during the filtering process flow back into the KSS because of the contaminated fleece.

Filtering baskets, dead space, fleece and filter mats can be effectively protected through the use of AGXX ® networks. Thus, following our experience, the main causes of additional high microbial contamination of the KSS are identified and eliminated.

Efficient filtering effect of AGXX® networks

The control of AGXX® networks in the KSS showed depending on preloading, age of equipment, maintenance conditions, etc. substantial deposits of biomass, production residues and other micro particles within 1 to 6 months. The microscopic analysis of AGXX® network mesh shows a fast absorption of micro-organisms and micro-particles in aqueous solution.

The efficient filtering effect of the networks leads to a continuous reduction of deposits on metal surfaces, in tanks and pipelines if the network surfaces are regularly cleaned with a special cleaning solution.

This additional positive effect can be optimized by further constructive adjustments in the form, positioning and transfer of AGXX® networks. With proper selection and application of matchingAGXX® modules a sustainable and long-term system cleaning and microbial decontamination will be achieved.

Resistance of AGXX® compared to active sulfur compounds and complexing agents

Further analysis of the network surfaces after 12 months of continuous use in KSS tank plants showed a high resistance to any chemical or physical contamination. Experiments for the preservation of KSS with products of the classic silver technology very quickly showed that ingredients of the KSS like active sulfur compounds, organic molecules or contamination from biomass greatly reduced the antimicrobial activity of silver up to rapid complete inactivation.

Testing the influence of active sulfur compounds on the antimicrobial efficiency of Ag and AGXX®.

The various samples were incubated for different lengths of time in 1% m / m K2S solution. Then the antimicrobial potential on nutrient agar with E. coli bacteria was tested.

K: untreated AGXX® control,
Ag: min silver sample for 5th in K2S,
P1: AGXX® for 5th in K2S,
P2: AGXX® for 10th in K2S,
P3: AGXX® for 30th in K2S,
P4: AGXX® for 1 h in K2S,
P5: AGXX® for 2 h K2S

Retesting of AGXX® after long-term applications in KSS tank farms proved, however, that AGXX® retains its full antimicrobial activity over long periods of time.

To systematically review the long-term stability of AGXX® to such contaminations, a quality test with potassium sulfide solution was established. It showed that even after long incubation in 1% K2 S-solutions the antimicrobial activity of AGXX® had not been reduced.

By contrast, all known classic silver products, novel silver surfaces, nano-silver or silver textiles show a complete loss of their antimicrobial activity after only short-term contamination with active sulfur compounds.

In the practical use of KSS there are various contaminations by active sulfur compounds and organic molecules, as well as biomass and metal abrasion. Also many micro-organisms produce active sulfur compounds such as hydrogen sulfide which are all very reactive towards free silver surfaces.

In cell walls and membranes of microorganisms there are also proteins and lipid molecules with reactive sulfur groups that additionally bind (link) silver ions, form complexes and inactivate them. Therefore, the consistency of silver-based disinfection systems against such contaminations is one of the most important basic requirements for practical use.

According to our tests only AGXX® has a sufficient resistance against these contaminations.

Change in strategy for antimicrobial preservation by AGXX®

The experience from the current practice applications demonstrate that AGXX® offers a new system solution for the sustainable conservation of KSS. Our system analyses in various plants have by now identified the most critical points for contamination and multiplication of germs.

The new strategy consists of placing AGXX®-protection systems at particularly critical points in the plant. Various industrial standard forms of AGXX® as modules, cartridges, filter boxes or network frames permit flexible and individualized problem solving on-site.

So long-term efficient filtering and microbial reduction can be achieved. It turns out that the removal of biomass, attrition and other residues from the entire system directly correlates with a long-term micribial preservation of KSS. With appropriate correct and consistent application of AGXX® a continuous cleaning of the entire system of biomass, turbidity and micro-particles is achieved.

Basing on the experiences of our practice tests, each user has his own criteria for the performance evaluation of the effectiveness of AGXX®. But the main criteria for the sustainable action of AGXX® always pop up again and are:

  • Reduction of biomass and turbidity in the system
  • Maintaining the production quality in metalworking
  • Extending the service life of the KSS
  • Reducing the number of bacteria and bacterial flora
  • Reduction / removal of biocides
  • Prevention / reduction of problematic waste and their disposal.
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