Southern Metal Finishing

Re: New technology for purifying contaminated Aqueous Solutions PART 1

[color="Navy"] This article was published in the June 06 issue of Southern Metal Finishing. If you would like register to receive our free newsletter and review our online archives please visit

A newly developed, patent pending process involves a novel and ideal method of purifying contaminated aqueous solutions without using any chemical agents has recently been announced to the metal finishing industry.

This process does not use any chemical agents or biologically active organisms.  It does not create malodorous effects, and does not produce (or with significantly reducing) any form of sludge as a by-product of treatment. As used herein, the term “contaminated aqueous solutions” refers to bulk aqueous solutions containing concentrations of colloidal particles, heavy metals, phosphate-containing species, micro-organisms, nitrogenous species, soluble organic matter, dissolved solids such as inorganic mineral salts, or any combination thereof.

This new technology separates contaminated aqueous solutions into (a) a liquid component comprising an effluent free of micro-organisms and heavy metals and having low concentrations of organic carbon, nitrogen, phosphorous and TSS and (b) a concentrated solids component comprising a reusable, dry solids residue containing heavy metals, alkaline earth phosphates and agglomerated colloids. Examples of contaminated aqueous solutions effectively treated by the present invention include sanitary wastewater, drinking water, groundwater, industrial process water and wastewater, landfill leachate, and diffusate or leachate extracted from soil.
Present state-of-the-art techniques for treating and purifying contaminated aqueous solutions primarily involve bio-oxidative techniques. Application of these bio-oxidative techniques is limited by serious problems. For example, transient conditions generate a chemical imbalance which does not allow for adequate phosphate removal and various factors complicate anaerobic digestion.

The problems and complications associated with conventional wastewater treatment systems  involve biological digestion of wastewater in the liquid phase, are well documented. The digestion process is susceptible to disturbances to flow, nutrient loadings, temperature, chemical content, accumulated sludge levels and other influences. Digestion requires long retention times in large tanks. Close supervision of the process by skilled operators is often required for acceptable performance, although such supervision is no guarantee of a good outcome. In secondary treatment, organic nitrogenous wastes are not entirely removed by the processes, but rather, are converted into soluble nitrate compounds that could potentially pollute surface and ground waters.

The proper disposal of sludge has become a major problem by virtue of its ability to collect and retain heavy metals and toxic chemicals present in a waste stream, as well as its daunting physical properties and large water content. Incineration, land filling, and ocean dumping all have major flaws and are strictly regulated. Due to the presence of bacteria in sludge, the impact of the disposal of sludge by land application is the likely invasion of the soil by heavy metals, toxic chemicals and pathogenic agents, in which case groundwater can be contaminated and can spread disease causing bacteria.
The problems and complications associated with conventional wastewater treatment systems are also encountered in the treatment and purification of other contaminated aqueous solutions, such as drinking water, groundwater and industrial process water and wastewater.

Use of Chemical Additives Various methods have traditionally been used for removing contaminants from aqueous solutions. At best all such methods remove only selected nutrient-containing solids and none can achieve ammonia oxidation. Most, if not all, involve the addition of large concentrations of outside chemical agents which, at least in part, ultimately end up in the effluent (treated system).  The addition of flocculating agents is frequently encountered in many existing treatment methods. Regrettably, in promoting both oxidation and flocculation simultaneously, the effectiveness of the processes is substantially diminished.

Other methods require the addition of large concentrations of sodium chloride to the feed. The addition of sodium chloride to the feed to be treated ensures the production of an effluent containing levels of chlorine-containing organic residues, chloride ions and halomethanes, which clearly does not meet current EPA standards for secondary treatment. Moreover, such chemical addition also produces a solids residue which necessarily contains chlorides and chlorinated organic species, both prohibitive contaminants by present day standards.  Yet another method involves raising the pH of the stream with lime to coagulate the dissolved and suspended solids, followed by separation of the solids, and finally by the addition of chlorinating agents to disinfect the partially treated stream.

Membrane Filtration Methods for treating sanitary wastewater utilizing a membrane filtration system which separates wastewater into liquid and concentrated solids components by means of membrane filtration have also been proposed. In one such method, vibratory shear methods are employed to minimize fouling or blinding of the filtration medium. The resulting solids component is thereafter dried, disinfected and deodorized by a variety of methods to facilitate storage and/or disposal.  The permeate produced by such methods contain both micro-organism and heavy metals, requiring elaborate, environmentally-sensitive and costly additive measures for purposes of disinfecting and deodorizing the permeate and chemically oxidizing putrescible compounds contained therein. The precipitate produced by such methods requires elaborate and costly post-filtration treatment methods such as composting with wood processing and cement production wastes and the end result is still sludge.

The ideal technique for treating and purifying contaminated aqueous solutions would be an economical, non-biological process in which all the contaminants of greatest environmental concern are either removed entirely or reduced to environmentally acceptable limits without the use of chemical additives or biologically active materials and without producing sludge as a byproduct of treatment. Despite the major environmental and economic concerns associated with the handling and disposal of sludge, to date, no method of treating such contaminated aqueous solutions has been developed, this new patent pending process finally provides the industry with such a method.

This newly developed process rests in part upon the discovery that the surface layer of colloidal particles, whether hydrophobic, hydrophilic, or a combination of both, can be permanently altered in such a way as to cause total and irreversible colloidal destabilization (agglomeration) of all the colloidal material present in an aqueous solution without the use of chemical additives. This novel phenomenon is apparently accomplished as a result of some, if not all, of the chemical and physico-chemical reactions that occur within the treatment system of the process.

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Re: New technology for purifying contaminated Aqueous Solutions PART 1

What is the best way to filter out waste water in a closed loop system.  I want to be able to reuse my rinse water over and over if possible.  I would be thankful for any help possible.



Re: New technology for purifying contaminated Aqueous Solutions PART 1

Has there been any progress with this method?  Has the patent been granted yet?


Re: New technology for purifying contaminated Aqueous Solutions PART 1

I think this is good because it is something eco-friendly. Just hoping this patent will be granted so that it can be use by the public. I am planning to use it on my wastewater system design because I find some cleaners to be much expensive for its purpose.