Recipient Organization
AIL RESEARCH, INC
57 HAMILTON AVE STE 205
HOPEWELL,NJ 08525
Performing Department
(N/A)
Non Technical Summary
The project will expand agricultural water resources by proving the efficacy with which a novel, thermal distillation process separates waste brine into pure water and solid mineralsthat can be landfilled or sold to a secondary processor for mineral recovery. In the preferred implementation, solar collectors supply the thermal energy needed to drive the process, thereby meeting USDA's program priority to expand the use of alternative and renewable energy. Although the projects seeks toexpandwater resources for agricultural, the technology to be proven will also address a second USDA program priority: aid agriculturally-related manufacturing by providing the country's food processing plants an environmentally acceptable, economical means of treating wastewater.
Animal Health Component
35%
Research Effort Categories
Basic
(N/A)
Applied
35%
Developmental
65%
Goals / Objectives
A large majority of the world's freshwater usage goes to agriculture - estimates put agricultural needs worldwide at around 70% of all human use. Furthermore agriculture's use of water is still increasing globally due not only to population growth, but also due to higher plant transpiration rates driven by increasing ambient temperatures. In many parts of the world this has led to significant drops in groundwater levels as it is pumped out faster than it can recharge.In California, where more than 60% of the U.S. fruits and vegetables are grown, agriculture accounts for approximately 80% of water use. The state estimates that groundwater is being over-pumped by at least 2.5 million acre-feet per year leading to twenty-one of the state's groundwater basins being identified as critically over-drafted. Under California's new Sustainable Groundwater Management Act, over 1 million irrigated acres in California, 10% of the state's total, are at risk being forced to be fallowed unless new water supplies are found.However, in California and elsewhere while freshwater reserves in the ground are shrinking brackish groundwater reserves are growing. This growth in brackish groundwater is mainly due to salts brought in with irrigation water, seawater intrusion in coastal zones or agricultural runoff. For example it is estimated that in California's Central Valley salts are building up at a rate of 700 million tons per year due to both the importation of irrigation water from the mountains and agricultural runoff high in nitrates.Brackish groundwater is mostly unusable for agriculture. As groundwater salts increase over 500TDS, plants grow more slowly, yield less, require more water, and suffer greater mortality. Salt buildup in agricultural basins is increasingly viewed as a long-term threat comparable to water shortage.Recent surveys have identified tens of billions of acre-feet of brackish groundwater underlying significant portions of the U.S. California alone has hundreds of millions of acre-feet of brackish groundwater--over one-fourth of all the water in the state. The use of these brackish groundwater reserves for agriculture could significantly ease over pumping of neighboring fresh groundwater reserves, allowing them to recharge.So why aren't we desalinating brackish groundwater for agriculture? The simple answer is that costs are much too high. Even for high value crops farmers can only afford to pay around $0.60 per cubic meter for water--a price that is about one-third that for potable water produced by the Carlsbad and Santa Barbara reverse-osmosis seawater desalination plants.With as little as 1/30th the salt concentration of seawater, brackish water should be less expensive to desalinate. However, a breakdown of the costs to desalinate brackish water shows that the process is heavily penalized by the cost of waste brine disposal. If disposal costs are ignored, a reverse osmosis facility could convert as much as 90% of brackish water to freshwater at a cost of $0.40 per cubic meter. However the 10% stream of waste brine with high salt concentrations presents an almost impossible disposal challenge, costing from $6 to $24 per cubic meter. Brine disposal increases the blended price for water provided by inland RO to between $0.95 to $2.75 per cubic meter--a price well beyond the $0.60 per cubic meter that growers of even high value crops (e.g., vineyards, tree nuts, tomatoes, berries) can afford.Why is brine disposal so expensive? Weight of the brine is the key issue. An RO facility treating 100 acre-feet of brackish water at 90% recovery will leave 10 acre-feet, 13,600 tons of brine to be disposed. The four environmentally approved disposal means now available - (1) transportation to an ocean disposal point, (2) injection into a deep well, (3) evaporation in a surface pond, and (4) evaporation in a dedicated thermal Zero Liquid Discharge (ZLD) facility--are all far too expensive.Of the four disposal methods now available, the one for which technology advances could dramatically lower disposal cost is the dedicated ZLD facility. Our primary objective is to bring to the market a ZLD process that immediately lowers disposal costs to less than $3.50 per cubic meter and, when mature, to less than $2.00. Once these objectives are met, the our ZLDtechnology will open the country's vast inland brackish groundwater reserves to agriculture. Furthermore by taking salt out of the agricultural water ecosystem the technology we develop will begin to reverse salt buildup in many of the nation's key agricultural water basins.
Project Methods
The development of the brine concentrator will proceed through multiple phases of laboratory testing in which small scale models are first operated with representative brine for increasing long durations leading to the operation of full-scale modules under conditions that simulate field operation. The experience from laboratory operation will feed into a design study, including engineering drawings of a 5-gpm deployable system that extracts at least 90% of the water from the waste brine discharged from a reverse-osmosis plant that processes brackish water. Computer modeling of the 5-gpm plant will determine its energy use and operating costs (dollars per cubic meter of product). An engineering analysis of the cost to manufacture the 5-gpm system will be used to estimate its final selling price to the end-user and the capital component of the cost to process brine (again, dollars per cubic meter of product).Laboratory tests of alternative configurations and materials for a brine crystallizer will be conducted. Detailed, post-test examinations, including SEM imaging, will determine which materials can meet the long term performance requirements of a brine crystallizer. Engineering drawings will be prepared of possible brine crystallizer.