Produced Water Treatment - Future Technology.
Polymer modified bentonite or organoclay, ET Ventures - ET #1, made by binding amine polymer with bentonite clay, this converts the clay to an oil-wet, hydrocarbon adsorbent material. Able to adsorb 88% of its own weight in hydrocarbons and 100% by volume. Combined with granular activated carbon treatment gives non-detectable levels of pet. hc's ,oil and grease, and soluble hydrocarbons (EPA methods 418.1 ,413.2 & 8020 respectivley). Units are nearly maintenance free. Spent ET #1 has shown to adsorb volatile hydrocarbons tighly enough to pass the EPA's TCLP test. This allows the product to be disposed of as non-hazardous waste. However until more experience is gained with the use of ET #1, operators should conduct their own TCLP test prior to disposal. The TCLP test, or the Toxicity Characteristic Leachate Procedure, is used to identify toxic chemicals capable of leaching into groundwater. The spent product can be returned to manufacturer for cost of freight. Alternatively, some manufacturers add activated carbon to the organoclay allowing the spent product to be burned as fuel in boilers. Research is still needed to prove this treatment method, for example, it is not know weather the product will concentrate heavy metals or weather the metals will be bound tight enough to pass the TCLP test. .
Because of the large volume of produced water, the cost of its management has a strong potential impact on the profitability of the domestic natural gas industry, and in some cases, the regulation of produced water disposal can shutdown production operations. Currently, about 60% of the produced water is disposed of through deep well injection at a cost of $0.50 to $1.75/bbl in wells that cost $400,000 to $3,000,000 to install. Furthermore, this option is coming under increasing regulatory scrutiny and is likely to be even more expensive in the future.Researchers at ANL have been using a new membrane technology called electrodialysis (ED), which is an electric-field driven process that uses ion-exchange membranes for salt removal or concentration.