Einfluß der Zusammensetzung nichtionischer Tenside auf den HLB-Wert für optimale Emulsionsstabiliät

Vorgestellt auf DECHEMA/GVC-Jahrestagungen 2004 - Karlsruhe 12. - 14. Oktober

siehe auch

Stability analyser Lumifuge 116 for rapid evaluation of emulsion stability and demulsifier selection

D. Lerche, T. Sobisch, S. Küchler, 2002

Rapid emulsifier selection and evaluation of emulsion stability by analytical centrifugation

T. Sobisch, D. Lerche, 2004

Chemistry Preprint Archive, Volume 2002, Issue 6, June 2002, Pages 195-201
Chemistry Preprint Archive, Volume 2004, Issue 5, May 2004, Pages 7-18

Motivation

Der HLB-Wert repräsentiert die Gesamtpolarität des Emulgators, unabhängig von der Zusammensetzung - egal ob Einzeltensid, Mischung zweier Tenside oder Gemisch mit breiter Verteilung. Andererseits ist bekannt, daß die Geometrie der Tensidmoleküle und ihre Packungsdichte in den Adsorptionsschichten einen deutlichen Einfluß auf Typ und Stabilität der Emulsion hat.

Neben dem summarischen HLB-Wert sollte die Tensidzusammensetzung einen wesentlichen Einfluß ausüben.

Für das Emulgatorsystem iso-Tridekanol/ethoxylierte iso-Tridekanole wurden entsprechende Untersuchungen mittels analytischer 'Multiproben' Zentrifugation untersucht.

Experimentelles

Die Messungen wurden mit dem Stabilitätsanalysator LUMiFuge 116 durchgeführt.

Diese analytische Zentrifuge mißt lokale und zeitliche Änderungen der Transmission bei 880 nm zeitgleich während der Zentrifugation.

8 verschiedene Proben können gleichzeitig bei Temperaturen bis zu 60 °C vermessen werden.

Der Entmischungsprozeß kann als zeitliche Änderung der Transmission oder der Position der Phasengrenze dargestellt werden, wobei sich letztere mit hoher Genauigkeit bestimmen läßt.

Welche Informationen liefert die Analytische Zentrifugation


Unterscheidung o/w oder w/o Emulsion, die Abscheidung der kontinuierlichen Phase ist der primäre Entmischungsprozeß



Abhängigkeit der Entmischungsgeschwindigkeit von der Zentrifugalbeschleunigung


Untersuchung der Kinetik der Entmischungsprozesse

Einfluß von Mischdauer, Emulgatorzusammensetzung, Temperatur
Paraffinöl-Wasseremulsionen (1/1 v/v), Emulgator 5%, Dissolver 5000 rpm


Abhängigkeit der Emulsionsstabilität von der Mischdauer,
vom HLB-Wert ethoxylierter iso Tridekanole und von Mischungen mit iso Tridekanol.


# klare Synergieeffekte iso-C13-OH/EO12
# Kinetik und Stabilität unabhängig HLB 4 - 10 (analog C13OH + 5 EO, siehe oben)



Abhängigkeit des HLB Optimums von der Zusammensetzung der Tensidmischung und der Temperatur

# ab EO7 ist die Emulsionsstabilität unabhängig vom HLB-Wert # Mischung C13OH/EO3 ermöglicht erhöhte Stabilität # Temperaturerhöhung über 45 °C verschiebt HLB Optimum # Mischungen mit höher ethoxylierten Tensiden sind weniger temperatursensitiv

CARBOWET® DC01 SURFACTANT PROVIDES PAINT AND COATINGS INDUSTRY WITH AN APE-FREE ALTERNATIVE AND IMPROVED PERFORMANCE

October 28, 2004

Extracted from Press Release - Airproducts

.........Carbowet DC01 surfactant is a synergistic blend of nonionic surfactants and can be characterized as a multi-functional, low-foaming, solvent-free and APE (alkyl phenol ethoxylate) free additive for pigment and substrate wetting. "We developed and benchmarked the product against standard and modified APEs, and this new product showed numerous potential benefits for water-based architectural and industrial coatings," Shah said.

This unique, proprietary product was designed to provide rapid substrate and pigment wetting, as well as better compatibility with associative thickeners and wide compounding latitude. Customers may be able to realize a potential cost savings due to reduced levels of associated thickener. Benchmarking tests also showed increased scrub resistance. The product exhibits enhanced surface tension reduction for improved wetting on pigments and poorly prepared or chalky surfaces. Carbowet DC01 surfactant is a clear, low odor, low viscosity liquid. The product has a lower pour point than typical commercial surfactants used in architectural paints, allowing for better handling in cool temperatures.

Poor European Test Standards Understate Air Pollution From Cars

Pollution Online News for pollution control professionals

News from Pollution Online
10/26/2004

Inadequate test standards are underestimating emissions of harmful air pollutants from new cars and evidence indicates that many diesel car owners are making things worse by modifying their engines to increase power, the European Environment Agency recently warned.

These factors may be among the reasons why air pollution in Europe's cities is not falling faster, the Agency says in a new report, Ten key transport and environment issues for policy-makers.

In addition, because the test cycle for new vehicles does not cover air conditioning and some other types of energy-consuming equipment, Europe's progress towards cutting new cars' emissions of the greenhouse gas carbon dioxide (CO2) appears greater than it really is.

"Ensuring that vehicles actually meet the emission standards in the real world should be a priority," Prof. Jacqueline McGlade, EEA Executive Director, said in a speech to a high-level Dutch government conference on sustainable mobility held in Amsterdam today. The two-day conference will make recommendations to the new European Commission taking office next month.

The EEA report and an accompanying briefing paper, launched at the conference, show that transport volumes are growing at roughly the same rate as the economy – despite the European Union's goal of weakening this link - and continuing to intensify pressures on the environment.

These pressures include rising emissions of climate-changing greenhouse gases as the market shares of road and air transport continue to grow at the expense of less energy-intensive modes, as well as threats to biological diversity from the fragmentation or disturbance of wildlife habitats by roads, railways and airports.

Efforts to counter these trends are at best only slowing the rate of increase.

Improvements in vehicle technology are succeeding in reducing air pollution from road transport despite the growth in traffic volumes. Emissions of regulated pollutants (excluding those from aviation and marine shipping) fell by 24-35% between 1990 and 2001 in the 31 EEA member countries.

But transport-related air pollution in urban areas still contributes to tens of thousands of premature deaths each year across Europe.

Current test cycles for new vehicles do not reflect how cars are used under real driving conditions and so underestimate their actual emissions. This may help to explain why urban air quality is not improving as fast as vehicle data suggest it should, the report says.

The shortcomings of the test standards also mean that, while Europe's motor industry is on track to meet a commitment to reduce CO2 emissions from new cars by one quarter between 1995 and 2008, greenhouse gas emissions from air conditioning and other in-car equipment not covered could in reality cancel out around half of the improvement.

Even with the car industry's commitment, overall CO2 emissions from transport are projected to increase by 25% between 1990 and 2010, but without it the rise would be 35%.

Some 15% of the CO2 improvement achieved so far has been due to the increasing market share of diesel cars, which are more fuel-efficient than petrol vehicles.

But the practice of 'chip-tuning' diesel engines for greater power is a cause for concern because it increases fuel consumption and pollutant emissions. A recent report estimates that as many as half of new diesel cars may have been modified and that such changes can multiply their emissions, especially those of harmful particles, by up to three times.

On a brighter note, strong growth under way in the use of biofuels – transport fuels made from crops and other organic material – should help the transport sector to limit increases in its CO2 emissions. However, it is important that the biofuels are produced in ways that minimise other potentially negative impacts on the environment.

Further key messages from the report include the following:

Aviation is the fastest-growing transport mode and its impacts on the climate, from emissions of CO2 and other greenhouse gases, will soon exceed those of passenger vehicles.
Rail and bus fares are rising faster than the cost of private car use, giving cars an advantage over public transport. Progress is slow in restructuring transport charges to reflect different modes' costs in terms of damage to infrastructure and the environment.
Transport infrastructure, especially road and high-speed rail networks, is continuing to expand and thus further fragmenting the landscape. Optimising the use of existing infrastructure through road pricing or congestion charging would allow this growth to be limited.
The report is available at http://reports.eea.eu.int/TERM2004 and the briefing paper at http://reports.eea.eu.int/briefing_2004_3/en

About the EEA
The European Environment Agency is the leading public body in Europe dedicated to providing sound, independent information on the environment to policy-makers and the public. Operational in Copenhagen since 1994, the EEA is the hub of the European environment information and observation network (Eionet), a network of around 300 bodies across Europe through which it collects and disseminates environment-related data and information. An EU body, the Agency is open to all nations that share its objectives. It currently has 31 member countries: the 25 EU Member States, three EU candidate countries – Bulgaria, Romania and Turkey - and Iceland, Liechtenstein and Norway. A membership agreement has been initialled with Switzerland. The West Balkan states – Albania, Bosnia and Herzegovina, Croatia, the former Yugoslav Republic of Macedonia, and Serbia and Montenegro - have applied for membership of the Agency.

Source: The European Environment Agency (EEA

Europaweiter Aktionstag gegen EU-Militarisierung- voting against the draft of the european constitution

Schritte zur Abr?stung

Am kommenden Freitag, 29. Oktober, soll der EU-Verfassungsentwurf durch die Staats- und Regierungschefs der Mitgliedstaaten der EU unterzeichnet werden. Danach wird in den einzelnen Staaten der Ratifikationsprozess beginnen.

Die Deutsche Friedensgesellschaft - Vereinigte KriegsdienstgegnerInnen (DFG-VK) ruft in Abstimmung mit weiteren Organisationen aus dem In- und Ausland für den selben Tag zu einem europaweiten Aktionstag (www.dfg-vk.de/eu2910) unter dem Motto "Europa in schlechter Verfassung" auf, da mit diesem Verfassungsvertrag unter anderem die Militarisierung der Europäischen Union bis hin zur globalen Kriegsführungsfähigkeit vorangetrieben wird (www.dfg-vk.de/eu2910/#begruendung)
Um den Protest gegen die Unterzeichnung dieser EU-Verfassung auszudrücken, hat die DFG-VK zusätzlich zu den sonstigen Aktionen (www.dfg-vk.de/eu2910/aktionen.html) eine E-Mail-Aktion ins Leben gerufen, mit der alle Staats- und Regierungschefs bis kommenden Freitag über deren Ständigen Vertretungen in Brüssel angeschrieben werden sollen.

Damit soll die Diskussion für einen neuen Verfassungsentwurf weitergeführt werden, der u.a. die Verweigerung des Krieges vorsieht.

Am 29. Oktober 2004 soll der EU-Verfassungsentwurf durch die Staats - und Regierungschefs der Mitgliedstaaten der EU unterzeichnet werden. Danach wird in den einzelnen Staaten der Ratifikationsprozess beginnen.

Ich möchte Ihnen mitteilen, dass ich diesen EU-Verfassungsvertrag ablehne, weil mit ihm meiner Meinung nach

- die Militarisierung der Europäischen Union, bis hin zur globalen Kriegsführungsfähigkeit vorangetrieben wird;
Die Finanzmittel für die Um- und Aufrüstung der EU-Armeen sowie für neue Kriege werden auch durch den Abbau von Sozialsystemen in den EU-Mitgliedstaaten erkauft.

Das größte Manko des Verfassungsentwurfs ist die fehlende öffentliche Information und Diskussion der Inhalte.

Um zu verhindern, dass dieser Vertrag in Kraft tritt, unterstützen wir eine große öffentliche Kampagne, die die Bevölkerung über die Inhalte dieses Vertrages aufklärt.

Setzen Sie sich mit mir für einen neuen EU-Verfassungsentwurf ein, der auf breiter gesellschaftlicher Basis unter Einschluss sozialer und emanzipatorischer Bewegungen entsteht, der eine Europäische Union schafft, die sich dem Krieg verweigert und der die Vision einer demokratischen, sozialen und zivilen Europäischen Union erfüllt.

Mit freundlichen Grüßen
T. Sobisch

On October 29th 2004 the draft for the EU constitution is intended for
signing by the heads of state of the EU member states. After that the ratification process is supposed to start in all 25 EU countries.

I want to inform you about my opposition to the ratification of this constitution treaty. Because I believe it enforces the militarization of the EU for both political and economical reasons, with the prospect of a capability to wage war worldwide.
The budget for armament and restructuring of the EU forces as well as the financing of "New Wars" will be paid for by cuts in social systems.

The obvious drawback of this constitution treaty is the lack of public information and discussion of the content of the draft.

I want to let you know that in order to prevent this constitution treaty from being passed, I support a Big Public Campaign that aims at informing and warning the public about the contents of this draft constitution.

Let me just say: Please take part in campaigning a new EU constitution with all social movements in the EU to make sure that it will be broadly based.
We need a EU which refuses war and which includes a vision of a democratic, social and civil society.

Yours sincerely

T. Sobisch

One more reason to replace chlorination in wastewater treatment - ein weiteres Argument gegen die Chlorierung bei der Abwasserbehandlung

NIST Tech Beat -September 28, 2004

News from the NIST-website

What happens to painkillers, antibiotics and other medicines after their work is done, and they end up in the wastewater stream? The National Institute of Standards and Technology (NIST) is using laboratory experiments to help answer this question by studying what happens to pharmaceuticals when they react with chlorine—a disinfectant commonly used in wastewater treatment.

Scientists around the world often find drugs in water samples taken from streams and other waterways, but little is known about byproducts of those drugs created during chlorine treatment or time spent in the environment. The topic drew a large audience at the American Chemical Society annual meeting last month, where NIST chemist Mary Bedner was one of several presenters. Among the concerns is possible damage to the environment, animals or people from bioactive compounds.

NIST chemists selected four pharmaceuticals sometimes found in the environment, studied their reactions with chlorine over an hour (a timescale during which significant wastewater treatment occurs) and identified the resulting products using multiple techniques. Scientists found that the reactions are complicated and often produce several products, some unexpected. For instance, acetaminophen forms multiple products, two of which are highly toxic. All the drugs were transformed significantly, and their products were generally more "hydrophobic" than the parent pharmaceuticals. Hydrophobic compounds are more likely to build up in the body. It is not known whether these reaction products pose any health or environmental hazards.

"We have unique measurement capabilities here at NIST, which help to confirm the presence of products that are difficult to identify," says chemist William MacCrehan. Measurement techniques and data collected throughout the project should help other laboratories further investigate possible health or environmental effects.

Ozonation leads to a reduction of toxicity

Discussion on combined sewer overflow, chlorination, hexavalent chrom

Charles Budinger wrote:

I have been reading some of your responses to the removal of hexavalent
chrome on the Water and Wastewater.com Help Forum website. I seems the
processes that you describe are for "uniform" waste streams, that is for
waste streams that come from a single facility. Would the process of
chromium removal be the same (and the results be the same) if applied to a
Combined Sewer Overflow facility that is treated by only filtering out the
floatables and then "shocking" the overflow with chlorine?

Presumably there is a high phosphate content and the pH is variable.
Obviously it would be high after the chlorine infusion.

I would suspect that the wastewater overflow is too turbid to treat for
hex-chrome removal.

Do you have any thoughts or ideas on this?

reply

Dear Charles Budinger,

unfortunately, I am not an expert on bichromate removal.
Why not asking Mr. Harrigan if he could imaging his principle working under these conditions.

Nevertheless, here some considerations

# high phosphate levels should assist threevalent chrome precipitation. Chromium phosphate is insoluble.
# high turbidity should not be an obstacle for precipitation or flotation. Instead it will provide surface for sorption and should therefore assist removal.
# I cannot see how chlorination should assist hexavalent chrome removal.


Charles Budinger

I guess my concern is not the precipitation of Chrome with the use of chlorine, but the production of hexavalent chrome from that process.

The turbidity seems to be the problem in that there are too many particles and other ions that interact with chlorine that seems to change the chemistry of the waste stream. That is, in the presence of an abundance of absorptive particles (extremely high turbidity and suspended solids), would chlorine have a preference towards any individual chemical compound and how would that affect chromium, specifically hexavalent chrome, production.

I was under the assumption, mostly from my background in mineralogy, that hexavalent chrome is found as a substitution mineral in sulfide.

But I think I am trying to explain this from the final state, rather than beginning at the origin of the problem.


reply
why the chlorination?


Charles Budinger

Yes, that is the point of misunderstanding. The chlorine is used as a disinfectant for a Combined Sewer Overflow System. If you are unfamiliar with that system, it is a municipal sewer system where the sanitary and stormwater is combined in the same sewer system. When rain events generate runoff that exceed the capacity of the pipes to transport it to the waste treatment plant, it goes to an "Overflow" facility, where it is filtered of all the floatables (using gigantic wheeled screens that look like big hamster wheels you would see in a hamster cage). After the debris is collected, the combined sewage and stormwater is "shocked" with chlorine in the form of sodium hypochlorite. This is very caustic and changes the pH.

It is my assumption that this process could produce hexavalent chrome, based on articles I had read about wastewater and stormwater discharged to the ocean can cause tri-chrome to convert to hex-chrome. So, I began to wonder of the effect of chlorine on chrome and the chemistry of the two in this kind of environment. There seems to be some sort of connection between chlorine use and the generation of PCBs as well.

Incidentally, at the overflow facility, all the "treated" effluent is then discharged into the rivers. But the City of Atlanta has now developed a program that will connect all the overflow facilities to a deep rock tunnel system that will convey this wastewater to the treatment facility. The tunnels, to the best of my knowledge, will be mostly unlined. Therefore, all the wastewater will be directly exposed to the groundwater under the Atlanta area. So, this concoction of sewage stew will have the ability to seep into the aquifers underlying the Atlanta area. This introduces another level of concern for compounds such as chrome and PCBs.


reply

Dear Charles Budinger,

thank you for your kind introduction into the backgrounds.
I would suggest that under alkaline conditions nearly all of chromium (III) is precipitated as hydroxide or phosphate, with no or only minor oxidation (surface reaction on the precipitate).

Nevertheless, moderate alkaline addition (lime to bind chromium and to kill the bacteria) , eventually followed by addition of H2O2 or ozonation should have less negative effects on ground water than Na hypochlorite.

Charles Budinger
Or better yet, fully separate all the stormwater pipes and sanitary sewer pipes and no treatment is necessary, and no discharges to the streams or groundwater are made...almost ever.

It just seems that with the system that is being proposed in Atlanta is cumbersome and relies too much on the injection of chemicals into the system. It seems as though now they are proposing to chlorinate upstream of the overflow facility and then de-chlorinate downstream, or at the facility. That adds a bi-sulfide or some other such sulfuric compound which may actually interfere with that process that you proposed.

All in all, there is to much reliance on the injection of chemical compounds into the system that eventually overflows into a creek or into massive tunnels below the ground.

Thanks for your input. Although this does not resolve anything, your insights have been very helpful. It indicates that the best means to protect the public health is with complete sewer separation and not the reliance on the plethora of chemicals necessary to maintain a combined sewer system.

Rüstungshaushalt senken: Protestpostkartenaktion und Aktionstage in Berlin

Newsletter: Schritte zur Abrüstung

Im Rahmen der Kampagne "Schritte zur Abrüstung" (www.schritte-zur-abruestung.de) hat die Deutsche Friedensgesellschaft - Vereinigte KriegsdienstgegnerInnen (DFG-VK) am 31. August offiziell die Aktion "Rüstungshaushalt senken" gestartet.
Zeitgleich wurde sie allen Fraktionsvorsitzenden des Bundestages sowie einigen Ausschussvorsitzenden angekündigt, mit der Bitte um einen Gesprächstermin.

Mit der Aktion, die seitdem großen Zulauf insbesondere aus dem Osten hat, ruft die DFG-VK dazu auf, einige Zehntausend Protestpostkarten an Bundeskanzler Schröder zu schicken und so der Forderung einer Senkung des Rüstungshaushaltes Nachdruck zu verleihen. Damit greift die älteste deutsche Friedensorganisation aktiv in den "heißen Herbst" ein.
Mit der Zweitauflage erreichen wir jetzt eine Auflagenhöhe von 170.000 Postkarten.

Am 18. Oktober fahren wir nach Berlin!

Wir bereiten derzeit vor, in der Sitzungswoche ab 18. Oktober am Bundestag in Berlin präsent zu sein, um in der Zeit bis 20. Oktober mit Straßenaktionen und Gesprächen mit Abgeordneten unsere Haltung nach jährlicher 5%-iger Senkung des Rüstungshaushaltes zu untermauern.

Auftakt und Schwerpunkt zugleich wird eine öffentliche Aktion am 18.10. ab 10 Uhr vor dem Reichstag sein.

Geplant sind u.a.
Ø Großtransparente
Ø das Steigenlassen von 99 Luftballons
Ø große Luftballons mit 5 %-Symbol
Ø weitere 5 % Symbole (z.B. Styroporkonstruktion), Gebäck an Abgeordnete
Ø prominente Unterstützer (GEW, Attac, ver.di Jugend u.a.) mit kurzen Statements
Ø Handout mit DFG-VK Argumenten an Abgeordnete und Reichstagbesucher

Wir brauchen noch dringend Menschen, die uns dabei unterstützen, sich dafür ein oder zwei Tage frei nehmen können, um mit uns den Bundestagsabgeordneten zu zeigen, was wir von der Verschwendung der Rüstungsmilliarden halten.
Meldet Euch schnell bei:

Mitfahrgelegenheiten und Ansprechpartner:
Mit dem VW-Bus und den Großtransparenten am Sonntag, 17.10. ab München. Kontakt: DFG-VK München, Tommy Rödl, kampagne@dfg-vk.de, 089-89623446

Aus dem Ruhrgebiet. Kontakt: DFG-VK Bundesgeschäftsführer Joachim Thommes, thommes@dfg-vk.de, 0201-2696901

Diese Aktionstage kosten 1500 Euro, davon knapp 1000 allein für die unterschiedlichen Materialien (Transparente & Ballons).
Dafür benötigen wir auch Eure und Ihre finanzielle Unterstützung:
Bertha von Suttner-Stiftung der DFG-VK
Konto 8174607
Bank für Sozialwirtschaft Köln
BLZ 37020500
Stichwort: Schritte zur Abrüstung
Spenden sind steuerlich absetzbar

Removing spent surfactants used for cleaning of aluminium from wastewater - Water and Wastewater.com Help Forum

Water and Wastewater.com Help Forum - Removing surfactants from wastewater


Question by yingiv

I am interested in finding a treatment plan for concentrated Diversey Duroclean 909, an industrial surfactant used to clean aluminum parts. The cleaning solution is currently housed in a large tank (approx 200m^3), and it occasionally gets dumped, but obviously needs to be treated before disposed. Any suggestions would be most welcome!

--
Ivan


Answer

Dear Ivan,

the only information I found about the cleaner is that it is an alkaline cleaner, which is due to be checked for alkalinity during application by titration with hydrochloric acid and should be replaced when the required level of alkalinity is lost or at least after 30 days of use.
From this it is evident that it should be treated to remove alkalinity and aluminium and that it will be difficult to recycle.
Eventually by cautious neutralization aluminium might be precipitated. You might do some test in the lab. For the treatment I would suggest addition of carbon dioxide.
Further information about the cleaner composition will be necessary for additional recommendations. I hope surfactants are readily degradable as well as no recalcitrant chelatants are used. Otherwise, the cleaner should be replaced by another alternative.


Reply by yingiv

Thanks for the help everyone!

The contents of this alkaline cleaner is a variety of inorganics and organics: monosodium phosphate, sodium metasilicate, sodium tripolyphosphate, nonylphenol polyethylene glycol ether, sodium sulphate, sodium alkylaryl sulfonate, ethylene oxide

the cleaning process is essentially a dipping process. the aluminum parts are dipped into a large tank of this cleaner. currently the cleaner is being dumped into the sewage approximately once every 40 days. (as you predicted).

we are looking towards reducing the waste so that it can be reused for rinse water (in another part of the plant), but i suspect this may not economically feasible. if not, treating it to be sent to waste disposal is still an option. will an adsorber like activated carbon be realistic?


Answer

Dear Ivan,

Given the cleaner composition, I would strongly suggest to look for an alternative cleaner not containing alkylphenol polyethylene glycol ether. The problems relating to this type of nonionic surfactant were already discussed at this forum some times, mostly related to foaming (Tertiary-treatment-surfactant-foam) .
The other components do not posses dangerous properties.
(I have to correct you, the cleaner does not contain ethylene oxide - a cancer causing chemical, very reactive, forming polyethylene glycols on contact with water. Probably you mean ethylene oxide derivatives - which is a whole class of water soluble oligo- or polymers or related surfactants).
Shifting the pH to neutral, aluminumphosphates, silica gels will precipitate and oil and grease may bind to the newly generated surface or at least will be destabilized. This way using a separator you should be able to get rid of most of these contaminants.


Reply by grrun

I suspect that the pH of the cleaning solution may be high enough to act as a mild etchant to the aluminum parts and the surfactants help remove any oils that may be present on the surface of the parts. I agree with Sobisch that "cautious neutralization" would provide a good pretreatment for this type of solution. I would also suggest considering dissolved air flotation as a positive means of removing the precipitated solids and oils as well as a small portion of the surfactants.

The remaining, dissolved surfactants may be tolerated in a municipal treatment system, but you may still want to look for a cleaner with an alternate surfactant.

I also believe that any treatment of the water short of reverse osmosis would not provide a satisfactory rinse water because of the residual dissolved substances in the water which would pose problems in subsequent processing such as plating or painting.


Reply by cgillen

Dear Ivan,
It seems to me that this material would be ideal for biological pretreatment before disposal. Of course the pH would need to adjusted to near neutral and it would need to be aerated. From a quick look at the composition I suspect there will be sufficient phosphorous but a lack of nitrogen. This would need to be added - probably in the form of urea. Of course the addition of specialised microbes capable of degradation of surfactants and hydrocarbons would be required.
It should be possible to achieve a COD reduction of 60 - 70% at least and thus reduce inhibition on the sewage treatment plant.
If this is of interest please contact me directly.

Best regards,
Ciaran Gillen
cgillen@biofuture.ie