Onsite Energy Efficient Waste Water Recycling by Distillation

Abstract. The cost effective recovery and reuse of wastewater generated on site by industrial, commercial, farm, and residential water users and polluters can significantly reduce reliance on scarce or expensive municipal water supplies and importantly prevent or mitigate wastewater pollution of the environment.

The requirements of centralized and decentralized wastewater treatment have become more demanding and complicated often requiring advanced treatment. In addition to eliminating pathogens, common sense objectives now include an ability to recycle phosphorous to soil, separate heavy metals, prevent nitrogen from depleting oxygen in coastal waters and remove or destroy potentially harmful chemicals and pharmaceuticals. Most centralized and all virtually all installed decentralized treatment systems are insufficient to completely protect water consumers and the environment. Advanced treatment in a few municipal centralized installations and a larger number of industrial applications involve combinations in series of micro/nano filtration, chemical additions and controlled pH, reverse osmosis, UV, ozone treatment, and carbon adsorption are slowly being employed for advanced treatment, but these integrated systems often require coordinated steps in series, chemical disposable of additives, routine disposal of filters in landfills, trained operator oversite, and high maintenance with the result that they are not well suited solutions for small and medium sized installations needed for most onsite applications. Onsite treatment employing energy efficient distillation can meet or exceed the water quality performance of advanced treatment centralized and industrial systems at significantly lower total cost per gallon of water treated and delivered to consumers because transportation costs are largely eliminated. High priority decentralized applications include livestock, poultry, fish farming, grey and black water from commercial buildings and hotels, industrial processes and single family septic systems.

Distillation of wastewater produces the gold standard of purity and reliability to produce recycled water cleaner than rain. The distillation process is safe, reliable and largely agnostic to the presence of known and unknown harmful contaminants. This paper presents the capabilities of a small scale energy efficient distiller that captures and reuses 99.3% of the heat of vaporization, requires inconsequential disposables other than electricity, is self-cleaning to prevent build-up of calcium carbonate which quickly degrades the efficiency of other distillers, and requires little oversite and maintenance. Total energy use is 20 Watt-hours/gallon of distillate produced which equates to a fifth of a cent per gallon at ten cents per kWhr. Amortized equipment capital cost is about the same as operating cost. Processing sewage,ZLD or MLD is achievable at approximately 40 W*hr/g

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