AquaReclaim

comprehensive, scalable, and flexible treatment process
for Recycling Agricultural Drainage Water

Overview

Drainage water leaving our agricultural growing areas has been untreated for decades. Over time, the impurities in the drainage water such as sulfate, chloride, nitrate, and pesticides have flowed into our streams and groundwater causing widespread environmental damage. Farmers have struggled to find a comprehensive way to treat the water so it can be reused. But treating Ag drainage using only existing processes without innovation has not worked for anyone – growers, government regulators, or the general public. 

Introducing AquaReclaim – Innovation Driven Water Treatment Process

AquaReclaim is a comprehensive, scalable, and flexible treatment process for agricultural drainage that:

  • Recovers 70-80% of incoming drainage water
  • Removes and destroys pesticides
  • Lowers Ec dramatically, often below 1 mS/cm
  • Removes regulated contaminants like nitrate and chloride
  • No toxic or hazardous chemicals used

The process utilizes two Tailwater innovations:

Our PhytoVap hydroponic water treatment system and YieldMax, our anion removal system that also removes chloride. By selectively removing calcium and sulfate at the beginning of the process,  the remaining anions such as chloride, nitrate, phosphate are easily removed via ion exchange.

The treated water can now be safely land applied,  reused in the irrigation process, or sent as makeup water for other water intensive processes that might be used.

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Artishokes Filed
TWS Staff Members Installing Pumps
Water Sampling
Halophyte Plant in Bucket
PhytoVap Process
Water Chloride Removal Solution
Chloride Removal

How it works

1. Iron and Manganese Removal

Incoming drainage water is first filtered to remove suspended solids and then treated with a catalyst to remove high levels of Fe and Mn. The process results in approximately 99% recovery.  The concentration of these two metals must be lowered significantly to avoid downstream equipment damage. If you water does not contain these metals,  this step can be eliminated.

2. Sulfate and Calcium Separation

The filtered water is then sent through a nano-filtration system designed specifically for the removal of 90% or more of  sulfate, often the anion with the highest concentration. The system also separates most of the calcium and magnesium, and organics like pesticides. The treated water continues on to our anion removal system. The reject water or concentrate, about 20-30% of the total flow is sent to the concentrate processor for the removal of supersaturated sulfate and calcium via crystallization. This process dramatically lowers the Ec of the concentrate stream and reduces the possibility of scale formation. The desulfurized water is then sent to our patent pending PhytoVap system for evaporation. A key note:  PhytoVap is a closed loop above ground evaporator using only plants

3. Chloride and Nitrate Removal

Treated water from our nano-filtration system is sent to our YieldMax system for removal of all anions, including chloride and nitrate. The brine, about 2-4% of the flow, from this process is treated to recover the most valuable ions for reuse.  This is a very low power process and has a very small footprint.

4. Final Step – Decarbonation

Treated water from the anion removal step contains only a single anion: bicarbonate, usually at a concentration of 700 to 1000 mg/L or higher. Bicarbonate is easily removed as CO2 from the water via air stripping.

Your Ag Drainage: Before and After AquaReclaim

Regulated IonDischarge LimitBeforeAfter
Chloride150 mg/L> 100< 20
Nitrate10 mg/L100< 5
Sulfate250 mg/L> 750< 50
TDS600 mg/L> 3000450-550

Frequently Asked Questions

Both of these metals are best removed at the end of the process when the pH is near neutral and nearly all competing cations and anions have been removed. But some may be separated by the nanofiltration step. Of these, unhealthy arsenic levels at the end of our process should be treated with dedicated arsenic adsorbents.

The basic process targets chloride and not sodium. However the NF step will remove about 20% of each, maybe more, often lowering these contaminants to below the regulatory concentration threshold.

Pesticide molecules are quite large and separated by the NF system into the concentrate. The concentrate is treated with an inline advanced oxidation (AOP) step prior to calcium sulfate precipitation/crystallization.

Yes, if they are not deactivated. Another function of the AOP process is to deactivate these organic molecules so the calcium sulfate will quickly settle as a solid.

Generally speaking, the answer is yes. But this depends on level of sulfate we need to remove. At 1000 mg/L of sulfate in your drainage water, 70% is reasonable target according to the NF membrane manufacturers.

In most cases you’ll a concrete pad with a rain cover to house the system.

Of course. But you may need to provide some additional infrastructure that process needs such as compressed CO2.

The biggest energy user in the system is the nanofiltration system. All the remaining components generally require only a single phase 120V power.

Yes. The sulfate removal step produces calcium sulfate (gypsum) sludge. This material is not hazardous and can be dried outdoors then land filled. The PhytoVap system is normally designed to remove 90% of the incoming water within 1 day. Best practice would be drain the storage tank every two weeks or so and add this water to anion removal step for residual removal.

Yes! The RO could be sent to the anion removal step to remove any (-) ions especially chloride.

In general, we say no. But, minor adjustments can pay long term dividends as they can reduce the use of chemicals in the process and help prolong the life of the NF membrane elements. This is often the most effective way to reduce your long term treatment costs.

We use several chemicals in the process, but carefully curated to avoid creation of additional waste streams and avoid or minimize risk to employees.

  • Gypsum – we make a slurry of gypsum and use this to crystallize the dissolved calcium sulfate
  • Hydrogen Peroxide – small amounts of H202 are injected into the NF concentrate to breakdown antiscalants and destroy pesticides and other organic fragments.
  • 10% Ammonium Bicarbonate – we use this to regenerate our anion removal resin. We can process the brine to recover the ammonia and add it back into the regenerate solution.
  • CO2 – we used compressed CO2 to acidify the water just before the decarbonation step.
  • Air – we use compressed air to decarbonate the water at the end of the process

Pretty close but not 100%. All of the sulfate in your drainage water leaves the process as a solid. The ion exchange brine is treated to recover the ammonia. The residual brine is then decarbonated leaving a solution of water, nitrate, phosphate, and chloride. This mixture can be fed directly into the PhytoVap as our plants uptake all of these ions.

Your responsibilities are in two areas: preventive maintenance and managing the daily sludge production and chemical resupply. We will give you a checklist of what to check and when and what to do when one of our process indicators suggest a problem- e.g. reduced flow from the NF system. We strongly encourage you to engage with a local and state certified water treatment firm to maintain your system long term.

No, you can use your own but there are only a few NF membranes that are suitable for this process and we do control the specific type of resin used in the ion exchange process.

For moderate flow (15-75 GPM), it is usually less expensive to provide storage in plastic water tanks. For much larger systems, above ground reservoirs may be a better option.

Getting Started with AquaRefine

Step 1 – Contact

The first thing to do is contact us at 831-296-0535. Tell us about the drainage flow and provide any data you might have on daily and seasonal variations. 

Step 2 – Detailed Water Analysis

If you can, please provide us a recent detailed water analysis from your local lab. If you are unable to do this,  send us several 1 liter bottles of your drainage water and will insure it gets to our lab.

Step 3 – Preliminary Configuration and Cost Estimate

Based on the analysis of the water we’ll provide an initial estimate for the system. It is essential that we work closely so that the system is designed to meet your needs. We’ll need to carefully weigh the benefits of investing in recycling your water versus the total cost of ownership for the system.

Step 4 – Budgeting

This will be a capital expense for your company so senior management involvement and support at the beginning of the process is essential.

Step 5 – Construction

Construction of the system is mostly assembly and interconnection. Your existing electricians and plumbers can handle any tasks with bring the system on-line.  Tailwater will be there throughout the process to startup.