Patented Biological Treatment System For Nitrate Removal


BioTreat is a turnkey system that removes nitrate from any water source. The system employs a consortia of nitrate-reducing bacteria that converts nitrate (NO3) into harmless nitrogen gas (N2). The produced gas escapes naturally from the top of the system. The unit produces no brine or other waste. It is capable of reducing almost any concentration of nitrate in water to below 10mg/L – the national standard in the United States.

Innovative Solutions for Irrigation & Drainage Water in Agrluculture

We design, build, and operate systems for wastewater and well-water treatment and reuse. Our patented nitrate removal system is the best in class solution. Our brine reduction system is the lowest cost and most effective method. Our new salt removal system can remove 95% of the chloride.

Artishokes Filed
Wastewater Facility
Water Sampling
Strawberry Field

How Our System Helps You

BioTreat Systems offer a wide range of benefits.

  • Adaptable. The system design can treat almost any source nitrate contaminated water. Including brackish (salty).
  • High Performance. Our biological system can reduce nitrate to N2 in only a few hours of residence time.
  • Low Maintenance. Once the system is operational, customers only need to keep the system supplied with an external carbon source and prevent debris from entering into the system.
  • Small Footprint. The very high nitrate removal capability insures that the systems are compact and take up very little space on your farm or ranch.
  • Nitrate Credits. In California, our customers can claim nitrate removal credits (Rtreat) for any nitrate removed by our system. This has substantial agronomic benefits.
  • Affordable. The system has the lowest capital cost and operating expenses of any nitrate removal system commercially available.

System Specifications

Flow Rate2-500GMP
Nitrate Reduction
InputNo Maximummg/L
Reductionup to 100%
pH of Drainage Water6.8 to 7.5pH units
Carbon-Nitrogen Ratio6:1Lbs of carbon per lb
of nitrate removed
Oxygen Reduction Potential (ORP)-50 to 50mV (see note)1
Phosphorus Required20:1Nitrate:phosphorus

Note: Most drainage water contains more than enough phosphorus for denitrification to proceed. It is standard practice to add a small amount of phosphorus to insure we meet the nitrate:phosphorus ratio requirements.

How it Works

Biofilm Carriers

Our system is based on an established aerobic treatment system called the moving bed biofilm reactor or (MBBR) invented in the 1990s. Our implementation of this well-established technology uses a set of water tanks, usually plastic, filled with small plastic parts called biofilm carriers. The bacteria we use attaches and grows on these carriers. Because of the very large surface area of the biofilm carriers, we can pack a prodigious amount of bacteria into a single tank.

Anaerobic Environment

Inside the bioreactor tanks, we take active and passive measures to reduce the amount of oxygen in the water. During operation, the dissolved oxygen levels are very low – near 1 or 2 mg/L. This insures that the bacteria consume the nitrate molecules preferentially and not the oxygen.

Vertical Design

Drainage or tailwater enters the reactor tanks in the bottom, and moves upward through the tank. As the water moves upward, the water mixes with the biofilm carriers where the nitrate molecules come in contact with the biofilm/bacteria. The treated water then exits via gravity flow from the top of the tank. This upward flow ensures uniform (called “plug flow”) flow and results in excellent mixing of the water and the biofilm carriers. This vertical design also helps to reduce the physical footprint of the system.Inside the bioreactor tanks, we take active and passive measures to reduce the amount of oxygen in the water. During operation, the dissolved oxygen levels are very low – near 1 or 2 mg/L. This insures that the bacteria consume the nitrate molecules preferentially and not the oxygen.

No Special Hardware Required

We avoid any custom or “high tech” components in our designs. All of the components we use are often found in standard irrigation systems. We use centrifugal pumps to move the water through our system. Fittings are Schedule 40 and 80 PVC with heavy use of cam-lever (camlock) connectors. This simplifies connections and maintenance. Industry standard variable frequency drives (VFD) are used to control the pumps. The VFDs are enabled and disabled by float switches or sensors. We employ a variety of manual and electronic flow meters to monitor the water and carbon flow.

External Carbon Sources2

Biological denitrification requires a proper ratio of carbon-nitrate-phosphorus (C:N:P) to operate successfully. Most drainage water contains some dissolved carbon and more than enough phosphorus. The supplemental carbon can be supplied by a range of different sources:

  • Methanol
  • 50% Ethanol
  • Glycerin
  • 50% Acetic Acid
  • Sodium Acetate

Of these, we favor the use of ethanol and glycerin. Glycerin is a common by-product of biodiesel refining. Typically, this is the lowest cost source of external carbon. Ethanol can be easily produced by fermenting common sources of sugar (e.g. molasses), then concentrated to the appropriate strength (about 50%).

Biofilm Carriers
Figure 1. Biofilm Carriers
Glycerin Tote Placement
Figure 2. Glycerin Tote Placement

1 ORP may vary inside the bioreactor tanks. Since this is a “redox” reaction, ORP’s primary use is to monitor the C:N ratio. Changes in ORP over time can indicate that incoming nitrate concentrations are changing.

2 See this USEPA Link for a good discussion of external carbon sources for denitrification

TWS Staff Members Installing Pumps

System Components

The system has four major components:

  • Pretreatment System
  • Pumping & Control System
  • A Set of Bioreactor Tanks Filled with Biofilm Carriers
  • Power & Communications

The pre-treatment system normally consists of a supply tank to collect drainage from your irrigation sets. This tank provides constant head pressure for our main centrifugal pump. Filters, strainers, and particulate separators are used to keep suspended solids from entering the bioreactor tanks. Alternatively, a reservoir may be used as your pre-treatment or “holding” tank- with some careful consideration.

The pumping and control system utilizes programmable controllers, VFD’s for pump control, and industry standard protocols for controlling our pumps and acquiring data from any sensors or flow meters installed. To keep things simple, we normally design the system to operate from a single external switch. To do routine maintenance or perform other work on the system, technicians simply flip this switch to temporarily disable the system.

Bioreactor tanks are unpressurized, vertical above-ground tanks. Our design calculator tells us how big these tanks need to be and also calculates the amount of nitrate that will be reduced (to a gas). The only inputs we need from you to size the system are the flow rate, the incoming nitrate level, and how much nitrate you want to remove.

Power and communications can vary widely. For some users, the only control system elements are a VFD. For users that need to quantify their nitrate removal to obtain the so-called Rtreat data (California customers), a programmable action controller is used to collect flow rate data from the system automatically and log this data. Additional capabilities include remote operation- the ability to log into the system’s controller from your office and monitor system operation and vary the water flow rate or the amount of external carbon being used.

System Design & Configuration


The design process starts with your proposed location for the treatment system and a recent water quality test of the water that should be treated. Please use an “irrigation suitability analysis” for your test.

Key inputs we need for our design calculator are:

  • Flow Rate (see notes below)
  • Incoming Nitrate concentration
  • Desired Amount of Nitrate Removal, or, Target Nitrate in the Output (e.g. < 5mg/L NO3-N)

The calculator will then calculate the amount of biofilm carriers required, the size and number of bioreactor tanks, the residence time (how long it takes the water to transit our system), and the amount of carbon required daily.

Other Factors to Consider

Several other factors unique to your site can impact the layout and operation of the bioreactor. These include:

  • Source of water to be treated. We prefer to have your premise equipment keep our bioreactor tanks full.
  • Using a man-made reservoir/pond to collect drainage from your daily irrigation sets
  • Amount of suspended solids (dirt, clay, algae, other organic matter) in the water
  • Location of gravity discharge
  • pH of the incoming water
  • Nitrate removal monitoring

Nitrate Monitoring

Mostly likely, your team and the local regulatory authorities will want to know how much nitrate is coming into our system and how much is leaving. In general, nitrate monitoring is best done using test strips and/or an ion selective electrode with a handheld meter. There are continuous nitrate monitoring instruments that use specialized optics. But they are prone to interference from any number of ions dissolved in your drainage water. As of 2022, they are also extremely expensive and really don’t provide that much value.

Use a pond or reservoir for higher asset utilization.

When possible, we strongly encourage customers to use a small pond, reservoir or natural impoundment to collect your irrigation drainage. This allows our system to run for long periods of 20-22 hours per day at much lower flow rate. This enables a smaller and less costly system.

Optimizing the System Design

We can help you optimize the system design and operational costs for the most cost-effective
solution. The most important factors for optimization are:

  • System flow rate. Using a pond to collect drainage enables us to treat all the water from your daily irrigation sets more at a lower flow rate over 20-24 hours.
  • Amount of nitrate to remove. Many customers may be able to add a tertiary treatment to finish removing the criteria pollutants (usually nitrate). Examples are grass buffer strips. This reduces the amount of daily carbon required. Talk to your regulators and ag consultants- there may be other passive measures that you can take.
  • Reduce carbon application as input nitrogen falls. Most crops require heavy nitrogen application during their growth phase. As the plants need less nitrate, continue to lower your carbon application so that you maintain your target nitrate concentration in the effluent.

Acquiring Our System

There are three methods for acquiring our systems. These are:

  • Subscription
  • Purchase
  • License

The subscription method has the lowest up front cost to you but requires a monthly payment. It is similar to a lease but a big difference is that we do all maintenance and repairs.

Purchasing a system eliminates the monthly subscription payment but you must choose how you will maintain your system. We can do some of this for you with an extended maintenance contract.

For customers that need to install multiple systems, we can develop a licensing agreement that gives you the right to assemble, build, and operate our Biotreat systems. This is the overall lowest cost of acquisition (CAPEX) and operating costs (OPEX).

Not sure how to start?

We recommend that you begin with a subscription agreement on your first system. This gives you time to learn the ins and outs of Biotreat. At some point you may want to fully acquire the system after 24 months of operation.

System Pricing

A 50 gallon per minute should cost between $40,000 to $50,000 to install. This price can vary however, depending on options and other site-specific challenges. Monthly subscriptions can run from $2000 to $3000 per month.

Contact us to get a quote for your specific site requirements.

Installation & Setup

Once we’ve configured your system, we will have the large or bulky items shipped directly to your location. Our team will come to the site and setup the system for you. We will prepare the inoculum (bacteria culture that will grow in your tanks) and start the process of growing the nitrate reducing bacteria. Smaller systems (< 25 GPM) will be ready to use in about 1 week. Larger systems may take 10-14 days to fully inoculate.

Once the bacteria has had time to fully populate our tanks, we will start the system operating at a reduced flow. As the nitrate concentration in the outlet of the system drops to satisfactory levels, the system is considered fully installed and operational.

Natural Pond
Biofilm Carriers Being Loaded from bulk bag
Figure 3. Biofilm Carriers Being Loaded from bulk bag
Site Clearing with Tractor
Electrical Work

Your Responsibilities

We have a few requirements that customers must meet before installation can begin.

  • Site must be level with a several inches of crusher dust applied (very fine aggregate)
  • Provide electric power to the site
  • Provide a source of pressurized water to the system
  • Pre-treat your water, as necessary, to insure the incoming pH is between 6.8 and 7.5.