Color Removal with Membranes

Color Removal with Membranes

Membranes selectively remove dissolved species from a variety of sources including:

  • Surface water
  • Rinse water from fabric dyeing
  • Industrial wastewater
  • Color removal with membranesLandfill leachate

Demands for development of membranes with specific performance continue to increase as water quality requirements tighten and water treatment system designs become more complex. Such demands lead to development of new reverse osmosis (RO) and nanofiltration (NF) membranes with higher rejection characteristics for better dissolved salts and boron removal.

New applications have developed which require selective removal of certain dissolved species such as:

  • hardness
  • natural organic matter (NOM)
  • pesticides
  • Organic material which causes color

Engineers desire high removal of specific contaminants in these applications, but at the same time want to maintain some level of salts in the water so it does not become aggressive, which can cause corrosion problems with piping in the distribution network.

Nanofiltration (NF) membranes have good selectivity for removal of naturally occurring organic compounds as well as iron. Organic material can be found in groundwater sources which have surface water intrusion, or groundwater sources which are influenced by decomposing vegetative materials. The contamination of these waters is measured in terms of color units.

Treated water from landfill leachate is another source of color in wastewater. When this wastewater is discharged to a municipal treatment plant (POTW), color and the presence of certain organic acids affect the performance of the final ultraviolet treatment step, causing the receiving facility to require that these components be reduced or eliminated.

Dynatec has developed a number of options for color removal with membranes and organic acid removal. Since each project requires different levels of removal and has different treatment requirements, treatability work is typically carried out to establish the required treatment process steps. Typically, treatment requirements not only include color removal, but may also require the removal of COD, BOD, oil and grease, metals, etc. The treatment steps may include:

  • metals and/or free-floating oil
  • settleable materials removal
  • ultrafiltration for removal of suspended colloidal materials
  • nanofiltration using several options that are available, depending on the requirements of the particular application
  • reverse osmosis for the removal of color, dissolved solids and organics

Finally, some color removal can be accomplished with ion exchange resins specially developed for color removal.

Dynatec will carry out treatability work at their treatment lab or will provide small-scale pilot equipment that is shipped to the project site where longer term studies can be carried out.

Contact us today to discuss your wastewater treatment needs.…reatment-systems/

Containerized Membrane Bioreactor Systems

Dynatec provides completely packaged membrane bioreactor (MBR) systems installed in a shipping container:

  • Easy low-cost installation
  • No building required
  • Easily moved to other locationsContainerized Membrane Bioreactor Systems
  • Quick and easy mobilization

Dynatec has extensive experience in the supply of MBR systems, for sanitary and industrial applications.

Treatment of up to 35,000 gpd of sanitary waste in one container:

 Needs minimal operator attention

  • Uses long‐lasting out‐of‐basin tubular membrane
  • Produces high quality purified water

Dynatec’s containerized MBR system uses  tubular out-of-basin membranes. This concept provides many advantages:

  • The system has the ability to operate at much higher levels of mixed liquor suspended solids (MLSS) than conventional systems and immersed MBRs.
  • High levels of MLSS allow for higher levels of treatment, improved discharge quality, lower Waste Activated Sludge (WAS) volumes as well as increased flows from the same size reactor vessels.containerized membrane bioreactor systems
  • The concept is simple, requiring minimal operator attention.
  • An available option allows for remote monitoring and/or control for even less operator attention.
  • The system can be provided with aerobic digestion alone, or with nitrification/denitrification for total nitrogen removal.
  • The system is provided complete with system feed pumps and screening installed.
  • The membranes used provide up to 5-log levels of bacteria removal, reducing fecal discharge to non-detect levels.
  • The effluent from the system is suitable for many non-potable uses, including irrigation and toilet flushing. The effluent is suitable for further treatment, such as reverse osmosis without the requirement of any pretreatment, since no suspended solids are present, and residual organics are present only at low concentrations.

The MBR has proven to be optimal for treatment of many industrial wastewaters because it is less susceptible to upsets. The MBR’s performance is not affected by changes in sludge settleability like the conventional systems, making MBR a wise choice for industrial systems that have more difficult to treat waste streams. Dynatec has over 44 years experience in dealing with difficult to treat industrial wastewaters using membrane filtration.

Contact Dynatec Systems today to discuss your wastewater needs.

Wastewater reuse

Wastewater reuse is achieved at an automotive plant. Wastewater equipment to treat both sanitary and productionUltrafilter wastewater that included oily waste was designed and installed in a new transmission manufacturing facility.  The goal was to treat and purify water for reuse.

Dynatec met these demands by providing a membrane bioreactor (MBR) followed by a reverse osmosis (RO) system.  The MBR reduced BOD, TSS, and oil and grease to non-detect levels.  The RO is used to polish the MBR effluent so that it is suitable for reuse. It is reused in cleaning operations, cooling tower, and all production applications.

80%-90% of the wastewater is purified for reuse.  Additional industrial park wastewater (after primary clarification at the industrial park) is introduced to the system for treatment and purification.  The system is designed to receive 300,000gpd and purify 250,000gpd for reuse.

This novel approach greatly reduced the total amount of wastewater discharged by this plant.  It provided the water needed for production using a comprehensive system that Dynatec designed, supplied and installed.

Ultrafiltration (UF), Membrane Bioreactor (MBR), Nanofiltration (NF) and Reverse Osmosis (RO) are employed by Dynatec for these wastewater projects. Wastewater recovery and reuse has been successfully implemented with industrial and sanitary wastewater streams for:Reverse Osmosis

  • Cooling tower make up
  • Boiler feed
  • Irrigation
  • Toilet flushingWastewater reuse
  • Direct potable reuse
  • Cleaning/wash applications
  • Rinse processes
  • Painting processes
  • Other plant processes

For more information on wastewater reuse, please contact us today.

Silver Recovery at Microcircuit Plant

The Problem

A microcircuit materials production facility produces high purity silver in their process. The process produces a wastewater stream containing valuable dissolved silver compounds. The plant had an existing membrane treatment system to recover the silver from the wastewater, but the system had performance problems, required excessive maintenance and chemical cleaning costs were high.

The Solution

When the plant expanded its operations, they performed an evaluation. The choice was between expanding the existing membrane system or installing a Dynatec membrane system designed for simple automatic operation with low operating costs. Dynatec was ultimately selected to provide a complete system because the Dynatec design offered a more reliable, easier to operate process. The installation includes transfer pumps, two reaction tanks, three ultrafiltration skids designed for 25 gpm each with room for expansion, a sludge conditioning system, and a filter press.Silver recovery at microcircuit plant

The Process

Wastewater from the process is stored in an equalization tank. Transfer pumps deliver the equalized wastewater to the first reaction tank where DTC (dithiocarbamate) is added to react with the aqueous silver compounds to form insoluble metal salts. The water then enters another reaction tank where the pH is adjusted to optimize precipitation of the silver compounds.

The precipitated silver compounds are then filtered in one of the three ultrafiltration skids. The ultrafiltration system, using tubular PVDF membranes are designed for automatic operation. When the membranes become fouled, the operator initiates an automatic cleaning, and the system performs a chemical membrane cleaning and the ultrafiltration skid is brought back into service.

The permeate from the ultrafilter is discharged and the concentrated silver is sent to a sludge conditioning tank where a high molecular weight cationic polymer is added to aid in filterability of the sludge. The sludge is then sent to a filter press and the cake is sent to a silver reclamation facility.


The installation of the new system was successful. The system has been operating for several years. Current operation at the plant consists of operating two filtration skids at a time with one as a standby. The system is designed to add capacity by simply adding membranes to the existing UF skids. Operators are happy with the system’s operation and the lower amount of maintenance and chemicals required.

Contact Dynatec to discuss your wastewater application.


High Quality Discharge MBR

Dynatec provides High Quality Discharge MBR system for Retirement Home

The retirement community consists of independent living homes and apartment homes in rural Maryland. The facility is in horse country, in a valley among rolling hills, and shares the area with high-end homes.

Previously, the facility had two septic tanks, and a recirculated sand bed filtration system. This created odors and caused mosquito infestations in summer. The facility chronically missed discharge limits, and thus was paying frequent fines. The sand bed filtration system was high maintenance, constantly flooding and requiring maintenance.

Replacement Criteria

In deciding on a replacement system, several criteria were important to the facility and to State regulators. The plant must be aesthetically pleasing. Odors must be minimized and if possible, eliminated. The plant had to achieve high levels of treatment to meet present and future discharge requirements. Future use of the treated water for irrigation is planned. The plant had to be operator friendly, and be capable of being monitored remotely, since full-time staff would not be available. The plant must be cost effective, from both capital and operating standpoints. Finally, the plant must be modular, in that future expansion of the facility must be accommodated in the design.

The initial plant sizing was nominally for 50,000 gallons per day of treatment capacity and has been expanded to 100,000 gallons per day.Membrane BioReactor for Sanitary Wastewater

System Design

After a review of the available treatment options, the owners of the facility decided on the (MBR) Membrane Bioreactor option. Due to the modular design of the system, they also chose the out-of-basin membrane module concept provided by the Dynatec MBR system. This process combines ease of use with all the requirements of both the owners and the regulators.

Odor control is achieved by using closed tanks vented to atmosphere. Air from the screening room is used to provide aeration to the reactors and the membranes, using the biomass as a biofilter. The negative pressure in the screen room ensures that there are no fugitive odors from the area. Mixing and aeration of the EQ tanks (the existing septic tanks) ensures no odors from that area.

Design Compatibility with the area: due to the nature of the area, the plant was designed to be installed in a “horse barn”, or at least a building that looks like a horse barn, but in fact, contains both the treatment plant and space for landscaping and other equipment.

High Levels of Treatment have been achieved since the plant’s inception in early 2007. Performance has been maintained since that time. Future plans include treatment for Total-N and Total-P to comply with Maryland’s “flush tax” requirements.

Cost Effective Installation was achieved using standard above-ground HDPE tanks, rather than the more common concrete tanks

Plant Expandability was achieved by the installation of one half of the plant, and the addition of a second membrane rack. No modifications to tanks or other work were required in 2009.


Since completion and startup in early 2007, the plant has reliably performed, always producing high-quality water.

The Dynatec MBR concept provides economic advantages due to the modular design and the use of standard tanks. The cost of operation is modest when compared to alternatives.

Contact Dynatec Systems today to discuss your sanitary wastewater solution.


Decentralized Wastewater Treatment Facility

Dynatec provided the membrane system for a demonstration plant situated directly adjacent to the Anaheim, CA City Hall.  The system is designed to pump wastewater from a local sewer line, treat the wastewater for reuse, and return the waste activated sludge and screenings to the sewer line.Anaheim Case Study Photo 1

The DynaLift™ out-of-basin membrane system was selected because:

  • The high flux rates achieved by the DynaLift™ system allowed for a small footprint
  • High MLSS concentrations allows for smaller reactor tanks
  • The positive filtration achieved with MBR provides consistent high-quality dischargeSanitary Wastewater
  • The out-of-basin design allows for better demonstration of the technology
  • The membrane construction allows for high removal of bacteria and virus – demonstrated 5-log removal of bacteria and 4-log removal of virus.

The plant design is for two trains with the first train presently installed. The design flow of this plant is 75,000 gallons per day, and due to internal water uses, such as screen flushing, the net output of the final plant when fully installed will be 104,350 gallons per day. The recycled water is used for irrigation and toilet flushing within the requirements of California’s Title 22 Regulations.

Plant automation design allows for periodic operator attention only when equipment maintenance or chemical refilling is required.

Following treatment in the MBR, the effluent is further treated using ozone followed by UV for ozone destruction and chlorine addition at 1 mg/L to ensure no re-growth in the final effluent.

Due to the proximity of City Hall and the fact that the plant is in a highly populated area, a state-of-the-art odor control system was installed. With the standard Dynatec design odor control is not typically required.Decentralized Wastewater Treatment Facility

This is the first facility in California to use external MBR membranes, ozone and chlorination for water recycling. The use of decentralized wastewater treatment facilities is increasing and the City of Anaheim is in the forefront of this.


Contact Dynatec Systems today to discuss your wastewater reuse project.


MBR Leachate Treatment System

Prior to employing the Dynatec MBR leachate treatment system, the landfill was hauling all of their leachate. In 2010, the facility spent over $4,500,000 hauling 10,350 truckloads of raw leachate.

The landfill leachate was pumped from four different pump stations each with a different landfill contributory area. Analysis of the historical data showed the size of the contributory area and age of the landfill area played significant roles in flow and leachate quality. A few historical trends were identified and used to predict flows in a future landfill development scenario.MBR Leachate Treatment System

The MBR leachate treatment system was designed for the peak nitrification requirements of the influent. A large SRT (solids retention time) was selected to target the slowly biodegradable COD found in leachate due to long chain organic molecules that are more difficult to remove.

The system was designed with flexibility in mind. The MLSS can be increased to 20,000 mg/L in the system without affecting the oxygen transfer efficiency thanks to the jet aeration system selected, which enables the long SRT.

Dynatec’s industrial MBR is the ideal bioreactor configuration for treatment of organic or inorganic contaminants present in industrial wastewaters. MBR’s operate at a higher efficiency while achieving consistent design performance objectives. This makes MBR a more cost effective method of industrial wastewater treatment when performance and tank requirements are considered.

Industrial Membrane Bioreactors Benefits:

  • Higher flux
  • Lower costs
  • Better membranes
  • Improved permeate quality
  • Less operator attention and maintenance

Contact Dynatec Systems today to discuss your landfill leachate treatment system.

MBR for Cereal Manufacturer

MBR for Major Cereal Manufacturer

Dynatec provides a turnkey wastewater solution for a food manufacturing wastewater process.

The problem
A major cereal manufacturing plant needed to upgrade their treatment process. MBR was selected, and the company was about one month away from entering into a contract with a major MBR supplier of submerged hollow fiber membrane bioreactors. The cereal manufacturer has had chronic problems in procuring wastewater treatment systems that were able to meet required treatment levels.Industrial Membrane Bioreactors

Dynatec was invited to offer a proposal based upon our previous experience and successful implementation of membrane bioreactor systems in the food industry. Specifically, Dynatec had previously installed a  MBR system at another cereal manufacturing plant, which was operating without problems.

The Solution
When the two MBR systems were evaluated, Dynatec was selected. Reasons for selection were Dynatec’s experience with industrial wastewater, Dynatec’s record of success with other industrial MBR projects in the industry, lower cost and simpler operation.

The system had one major requirement. It had to provide reliable operation without a long process of evaluating problems and making changes to the system. For this reason, the  MBR process was used for its very reliable simple operation. A DAF was also provided by Dynatec ahead of the MBR system to remove solids and some BOD.
DAF effluent enters the MBR system for biological treatment and removal of solids. Some of the MBR effluent is reused on site for irrigation and other non-process uses. The other portion of MBR effluent is sent to a reverse osmosis system also provided by Dynatec. The RO effluent is used for cooling towers and other non-food reuse applications within the plant.
Dynatec was also engaged to install the system at the customer’s facility.

Contact Dynatec Systems today to discuss your wastewater application.

Flexographic Ink Wastewater Treatment


A corrugated box manufacturer utilized conventional batch physical/chemical treatment for processing wastewater generated from the clean-up of flexographic ink wastewater. The system consisted of chemical coagulation followed by conventional flocculation. A deep bed filter was used to clarify and dewater the waste. The system was operator intensive and generated lots of sludge for disposal.

Egg processing

A tubular non-clog membrane filtration system was installed to process the waste stream. The waste was pH adjusted to optimize the removal of copper and zinc. The waste was circulated through the filter for discharge and the contaminants were concentrated. The
concentrate of contaminants was reduced to 2% of the original volume. The system reliably produces high quality water with very little operator involvement.

Simple Mechanical Process:
The membrane filter is a mechanical system that allows clean water to pass through the filter while contaminants are rejected and returned to the waste holding tank. There are no chemicals required other than that which may be necessary for pH adjustment. Also, there is no sludge generated by the process. The system simply separates the contaminants from the water, whereas a chemical treatment system generates copious amounts of sludge that must be dewatered and disposed.

Unattended Operation:
Since this process is completely mechanical and not dependent upon chemical feed and the coagulation and flocculation process, the only operational requirement is to clean the membrane filters periodically. This is a simple process that involves less than one half hour of an operator’s time. A chemical treatment system requires ongoing adjustments of the chemical feed pumps, make-up of the chemical feeds, operation of the dewatering system and control calibration and adjustment. The chemical system tasks require continual attention on a daily basis, whereas the membrane filtration system requires attention only for cleaning.

Consistently High Quality Water:
The membrane filter forms a positive barrier to the flow of contaminants, producing continuous high-quality water without operator attention. The membrane system is not affected by variability of the waste stream. The purified water is suitable for reuse or sewer discharge.

Low Disposal Cost:
The mechanical separation produced by the membrane filter does not generate sludge. It simply separates the contaminants from the water and leaves those contaminants in a liquid phase. The amount of liquid concentrate is normally very small and it is, therefore, cost-effective to dispose of that concentrate as a liquid waste and thereby preclude the need to run and operate a solidification and de-watering operation.

Low Operating Cost:
The membrane filtration system will be the least expensive treatment system to operate. The cost of operation of a membrane filtration system is much less than a chemical treatment system.

Contact Dynatec Systems today to discuss your wastewater solution today.


Wastewater Reuse for Phosphate Mine

Mining operations can produce a large amount of wastewater in the form spent liquor that requires treatment.  The wastewater stream has a high concentration of contaminants that need to be separated from the water before it can be discharged or reused.  

Dynatec provided a wastewater reuse system for a phosphate mining operation that treats 5 million gallons of wastewater per day. The customer was motivated to put a treatment/reuse system in an effort to separate a portion of the compounds in the wastewater for reuse. Also, the desired water quality for discharge met requirements for reuse of several water users in the plant.

Wastewater Reuse for Phosphate Mine

 Dynatec was asked to conduct a pilot to study the feasibility of using membrane technology to purify the wastewater so that it could be reused in mining operations at the site. After several months of piloting, Dynatec was commissioned to supply five ultrafiltration skids, each capable of producing one million gallons per day of permeate. The ultrafilters were a part of the reuse system that also includes, nanofiltration and reverse osmosis to produce water and product for reuse.

Due to the highly saturated wastewater stream, the pH of the wastewater was maintained at 1.8 s.u. to keep specific contaminants from precipitating in the membrane systems. The ultrafilters have successfully operated at this pH for over 10 years and their life span has not been negatively impacted by the nature of the wastewater.

The high strength spent liquor is processed through a series of membranes from UF to NF to RO. The customer has found reuse applications for the reject and permeate from the membrane systems. The final system has alleviated concerns of future environmental infractions and has saved the customer money.

Contact us today to discuss your wastewater application.

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