WATER

Water is considered the universal solvent and has been the fundamental component of industrial and petrochemical development. Within the last century, the realization of a finite water supply has evolved. From shocking images of burning rivers and dead lakes to insidious birth defects, the impact of contaminated water has been broadcast worldwide. Society’s response has been the requirement for increasingly stringent treatment of water before use or release. The properties that make water a fundamental and important part of life also make it a difficult medium to purify. Contaminants can be dissolved, colloids, suspended, emulsified or any combination.

Water forms strong inter-molecular bonds due to the polarity of the molecules. These bonds hold contaminants in the solution matrix or water in the contaminant matrix. Energy must be added to destabilize this system and free the water. As a polarized solvent, the charged water particles cause ions to dissociate and become part of the solution.

Attractive forces that hold materials in the water and cause water molecules to align based on charge proximity also affect the physical properties of water. Water can absorb and hold significant amounts of energy with few changes in physical properties.

This brief description of the unique properties of water will help explain the effectiveness of the Joule technology.

TREATMENT COMPARISONS

Water treatment has changed little over the last centuries. In general the technologies have been based on chemical additions to create insoluble products from contaminants and filtration to capture contaminants. Where organic components are present, biological, absorption or vapor extraction mechanisms have been added to the treatment process as appropriate. No new or dramatic approach has been brought to the industry for forty years or more since the advent of Reverse Osmosis which employs high pressure filtration and ion exchange resins. Improvements in chemicals and genetically engineered or specifically cultured degradation organisms are the normal changes in process.

The Joule EP5™ offers an alternative to traditional water treatment. The Joule EP5™ must be differentiated from typical electrocoagulation and electroflocculation treatments. To address this issue, it is critical to understand the nature of water treatment, the levels of ‘clean” and the application of the Joule EP5™ technology.

Unwanted chemicals in wastewater may be categorized into numerous systems or formats. For simplicity, the categories discussed herein are:

Organic (fats, oils, grease, hydrocarbons, solvents, petrochemicals, food products),
Total Suspended Solids (non-dissolved inorganic materials in colloidal suspension or dispersion) also known as TSS, and
Total Dissolved Solids (chemicals intimately involved on a molecular or atomic level with water molecules) also known as TDS.

Organic materials are most commonly treated through biological degradation followed by settling and/or filtration. Air (oxygen) may be provided to enhance and sustain the biological activity. Nutrients may be added to optimize the metabolism and hence the decomposition of the contaminants. Ideally, the contaminants are converted to biomass, CO2 and water. The biomass is removed in the filtration step with incorporated contaminants. Organics that are not a food source to the organisms are removed from the water by mechanical means or through concentration on media that is further processed or stripping and concentration as vapor. Low concentrations of organic solvents may be removed by using UV light and/or ozonation.

All processes identified require sizable structures to accommodate flow or residency times. Current facilities represent significant capital expenditures and often do not meet current water quality standards. Facilities are forced to pay fines and fees (surcharges) to discharge over the legal limit.

Total Suspended Solids (TSS) are materials that can often be filtered from the wastewater. Filtration of large quantities of water is capital intensive and time consuming. More efficient separation can be achieved by altering the separation forces through centrifugation. The artificial gravity causes solids to migrate from the water to the equipment surfaces. These systems are either complex or expensive. Modern high-speed centrifuges can cost over $200,000.00 for 25 GPM capacity. Chemicals are readily available that react with the suspended solids and/or the water to enhance the separation and removal. Chemical treatment is the hallmark of the industry and the basis of all regulation. Additives function first to combine with the suspended solids and create larger particles that are easier to separate. Chemicals also are added to reduce the surface tension or polar attractiveness of the water allowing particles to move with less resistance.

Chemical treatment has advanced through the creation of new products that react more effectively with suspended solids. Some chemical treatments leave residual materials in the water. Overdosing is often practiced to accommodate variations in the wastewater. Residual treatment chemicals may cause the effluent stream to fail today’s stringent quality criteria.

Total Dissolved Solids (TDS) may be treated with chemical addition but most often more sophisticated methods are employed after the suspended solids are removed. Clarified wastewater can be treated with ion exchange resins, mixed resin beds, ultrafiltration or reverse osmosis. Resins are chemicals that attract and capture certain ions or molecules. Each resin is ion specific so a mixture of resins are needed to absorb the variety of ions found in wastewater. Resins can be washed to remove the captured ions. The resin wash is a concentrated waste to be treated.

Ultrafiltration and Reverse Osmosis(RO) are mechanical separations conducted under high pressure. Both utilize specially formulated membranes that allow smaller water molecules to pass through while capturing the larger contaminant molecules. Both processes then produce a concentrate stream that must be managed.

The resins and membranes will produce the highest purity water. Industrial and bottled water needs are met by some combination of these techniques. De-mineralized and ultrapure water used for boiler feed, pharmaceutical production, and in chemical reactions, are created by these techniques.

The Joule EP5™ fits between chemical/biological and De-mineralized/RO treatment. The technology is extremely efficient (>95% removal) on suspended solids and some dispersed oils and grease as well as inorganic dissolved solids. Joule EP5™ treatment is less efficient (>85% removal) on dissolved organics (COD, BOD, TOC) and some dissolved inorganic materials. The technology is inappropriate for “stand-alone” treatment of alcohols, sugars, amines, amides, pesticides, herbicides, chlorinated hydrocarbon solvents and complex surfactant/emulsifier solutions.

Joule EP5™ technology will enhance most treatment systems in use and can be a powerful tool in treatment systems under design. The versatility and consistent response of electropurification allows for a wide range of applications and less concern for wastewater consistency. Water treatment free from dosage and flow limitations or monitoring allows more flexibility of design and reduced costs of attention, maintenance, supplies, reagents, and down-time. High purity systems benefit from pretreatment by electropurification. Efficient removal of most contaminants serves to extend resin or membrane life and increase capacity of systems. Per unit costs are reduced in these applications.

Replacing chemical application with electrical energy reduces the volume of residuals. Chemicals added become part of the solids or sludge for disposal. Residual contamination blended with treatment chemicals loses recycling value. Contaminants precipitated through electropurification are concentrated and available for recycle or reuse. Chemical and biological water treatment processes generally produce a sludge with a high moisture content due to water bound in the purification medium. The Joule EP5™ technology releases the water from the contaminants generating a more stable and less bulky solid byproduct.

For an extensive discussion of the traditional water treatment technologies please see the publication by Metcalf and Eddy, Wastewater Engineering Treatment Disposal Reuse, Third Edition. This college text and reference will provide detailed descriptions of the technologies currently employed for traditional water treatment. Further information and details regarding the 1980’s electrocoagulation can be obtained from the Western Research Institute’s evaluation of Ligget EC technology (Ligget 1981 patent). Ligget is believed to have resurrected the concept of electrical treatment of water and spawned a number of new developments.