Iron, Manganese, Sulfur-The Troublesome Trio

Commonly referred to as the Troublesome Trio, Iron, Manganese and Sulfur, although not a real health concern, these dastardly elements will reap havoc on a plumbing system.  As little as 0.05ppm of Manganese will cause staining of plumbing fixtures.  Only 0.5 ppm of iron will cause staining.  And Sulfur?  P.U.!  Need I say more?

To battle the Trio, professionals have traditionally used Ion Exchange water softeners and Oxidation/Reduction media.  Ion Exchange only works on dissolved iron and manganese and is prone to fouling and won't treat sulfur.  So my experience is to apply oxidation media that has been treated with a coating of Manganese Dioxide.  These media are popular in the industry and are sold under the trade names of Birm, MTM,  Pyrolox, Filox, and Greensand Plus.  All these media have different percentages of manganese dioxide coatings.  The amount of coating determines their capacity.  The key to success lies with this capacity.

Manganese Dioxide acts as a catalyst that utilize oxidizers fed into the water stream ahead of the media bed to perpetuate the oxidation and reduction process.  Pre-feeding oxidizers is commonly called "regeneration". Please note, in all my years of experience, your success with these media depends heavily on choosing the correct oxidizer.  It is a VERY rare application where you don't need to pre-feed an oxidizer.   The most popular oxidizers are potassium permanganate (very messy because it stains everything purple) , Sodium hypochlorite (bleach), Air, or 7% Hydrogen Peroxide.  The most popular is bleach.  Be careful to follow the manufacturers guidelines for feeding oxidants.  To much will strip off the manganese dioxide coating.

Now The Exciting News:
Prince Minerals has developed a new Media called Pyrolox Advantage (PA).  PA is manufactured with a proprietary process that gives it a high capacity, yet maintains a lighter-than-most density so backwash rates are greatly reduced over traditional Manganese Dioxide products.  Thus the "Advantage" part.  Additionally, its lighter density will make it a direct replacement for another popular media called Greensand Plus.  An even bigger advantage, is that Pyrolox Advantage has nearly 3X the oxidation capacity.  Its increased capacity will lengthen run time between back washing saving significant amounts of water.  To conclude, if you are currently filtering with greensand plus or are battling any of the Troublesome Trio, please try Pyrolox Advantage.  It's priced right to win the fight!

1.4 MILES of Wire Saved Through Innovative PLC Architecture

,,,and over 800 electrical and 40 instrument air connections!

The field wiring for our customer became very complex because they wanted verification that each of the twenty actuated valves is in the correct position.  Also, the system is pre-programmed to allow up to four additional greensand filter units through a HMI touchscreen. If the control panel with the Allen Bradley PLC is only 10 feet from the first tank, fully outfitted, this control architecture would save over 2.8 MILES of wire, 1600 electrical terminations and 80 pneumatic connections and countless hours of wiring and troubleshooting!

Fieldbus Distributed I/O Module Blocks Installed n Each Greensand Filter Unit

One of the above fieldbus distributed I/O module blocks are installed on each of the four greensand filter systems for a local brewery.  This efficient architecture:

• Requires only two cables (Ethernet and low voltage Power) from each block to the main control panel eliminating point-to-point wiring from each system to main control panel
• Eliminates over 840 sources of potential errors by mechanical contractors during field installation (800 electrical terminations and 40 pneumatic connections)
• Eliminates enclosures with a total of over 40 penetrations
• Reduces the PLC inputs and outputs by 40, thereby reducing the size of the main panel
• Is rated IP67 (Dust tight and submersible to 1 meter)
• Operates at 24 VDC

The fieldbus system we employed is the PLC distributed I/O system (remote I/O modules) that is connected to the PLC using network called fieldbus. Typical fieldbus examples: Profibus, CAN, Modbus, ControlNet, DeviceNet, Ethernet I/P. At our customer, Res-Kem used  Ethernet I/P (I/P=Industrial Protocol) fieldbus. Each block must have communication adapter that is connected to the PLC network. At our customer, the Ethernet Adapter connected to the panel Ethernet switch. In addition to I/O blocks, the vendor Res-Kem uses, has solenoid blocks that are acting like digital outputs and are attached to the I/O system. Each block (fieldbus system) is powered from 24 VDC power supply providing power for backplane.

Greensand Filters During Factory Testing Showing Location of Each Fieldbus Block

Normal practice is to add an electrical enclosure which has solenoid valves to operate pneumatic actuators and electrical terminal blocks for the limit switches and solenoid valve.  At the customer's site, each electrical enclosure needs to have point-to-point wiring to the main panel with the PLC.

Typical Solenoid Panel WITHOUT Limit Switch Terminations

More About Fieldbus:
Fieldbus is an industrial network system for real-time distributed control. It is an efficient way to connect instruments in a manufacturing plant.

From Wikipedia, "A complex automated industrial system — such as manufacturing assembly line — usually needs a distributed control system—an organized hierarchy of controller systems—to function. In this hierarchy, there is usually a Human Machine Interface (HMI) at the top, where an operator can monitor or operate the system. This is typically linked to a middle layer of programmable logic controllers (PLC) via a non-time-critical communications system (e.g. Ethernet). At the bottom of the control chain is the fieldbus that links the PLCs to the components that actually do the work, such as sensors, actuators, electric motors, console lights, switches, valves and contactors."

For Additional Information:
For technical help

Greensand filter bulletin

Customized Greensand Filter for Brewery Prepared for Shipping

With factory testing completed, Res-Kem's greensand filter with several advanced features is ready for shipment to a local brewery.  Because the water is integral to production of their beer, this expanding brewery needed features which are not typical for a greensand filter:

• Allen Bradley CompactLogix PLC with Ethernet gateway to communicate with the central plant control system.
• Expandable, in the field, from four to eight parallel greensand filter units without requiring reprogramming of the PLC.
• Multiple, user definable,  regeneration initiation options including manually initiated, differential pressure and/or totalized flow.
• Valve position feedback to insure when a valve supposed to be open or closed, the valve is in the correct position.  If incorrect, an alarm will sound and be indicated on the Panelview 1000 HMI.

Quad 48"Diameter Greensand Filter During Factory Testing

General System Information:
Four tank, continuous regeneration non-skid mounted greensand system with manual, differential pressure and/or totalized flow initiated regeneration. The system is constructed of four, 48" diameter fiberglass, non-ASME code, rated at 100 psig working pressure tanks. The system is controlled using an Allen Bradley CompactLogix PLC with an Allen Bradley Panelview Plus 1000 touchscreen HMI.  The system has Georg Fischer pneumatically actuated air-to-spring ball valves with visual and electrical valve indication.  The face piping is Schedule 80 PVC pipe and fittings.  Each vessel contains 38 cubic feet of Greensand Plus for high iron removal.  To allow for iron removal, the incoming water will be treated continuously with a chlorine dioxide generator.

Touchscreen Panelview Plus 1000 HMI for Equipment Control

For Additional Information:

Greensand filter brochure

To determine if a greensand filter will work for your company, contact us.

Greensand Filters Shipped to Western PA Water Plant

A western Pennsylvania, small private water utility, recently received four greensand filters to replace the filters that were failing.  Unable to get the original manufacturer to provide new, duplicate units, our customer found our website. 



Four New Greensand Filters and Greensand Media Ready for Shipment to Water Utility



Because of State regulations, the systems and their operation needed to be as close to the original as possible, otherwise new permits would be required.  Since Greensand is in very, very short supply, the media was changed to Greensand Plus from the same manufacturer.  Sodium hypochlorite is used to continuously oxidize dissolved iron in the water coming into the filters.  Also, these filters are very unique because they are much shorter than we normally manufacture.  Our normal tank straightside is 60".  These tanks are 36" straightside.  

Three of Four Existing Manual Greensand Filters Showing Tank Corrosion

What does the company do? Public water

What is the Res-Kem water treatment application? Green sand filter to removed dissolved iron


What are the savings and/or ROI the customer wants to achieve? Not applicable.  The customer is replacing old existing system with identical system


What are the operating conditions, e.g. flow, temp, continuous, etc.? 60 gpm, Well Water Intermittent Flow

What is the system configuration, e.g. # of tanks, standby units, etc.? Four greensand filters in parallel operation


Materials of construction of tanks, piping, valves, frame, etc.? ASME Code Steel Tanks, 6’ Diameter X 36” Shell straight-side , PVC glued with manual ball valves


Type of valves and actuators? Manual ball valves


Control philosophy? Backwash as required based upon differential pressure

Special Features? Short fat tanks, required to fit tight area

For Additional Information:
Greensand Filter Technical Bulletin
Greensand Plus Technical Data
For help sizing a new filter
For help repairing or rebedding a Greensand Filter

Iron and Manganese Removal Filter Shipped to Westchester County HQ

Res-Kem recently shipped a 52 gpm dual tank greensand filter to a Westchester County New York corporate headquarters campus.  This filter uses greensand to remove dissolved and precipitated iron and manganese from the water coming from the local public water system.

Dual 36" Greensand Filters with
Bray 31 Valves and Bray Series 93 Pneumatic Actuators

Water Problem:

At a Westchester County corporate headquarters campus, about 4 to 5 times a year, our customer experiences water quality and quantity problems. The campus receives its water from a local public water supplier. High levels of iron and manganese are present within the public water distribution system, and peak flow events such as hydrant flushing or firefighting activities have caused brown water to be drawn into their water system. What exacerbates the problem is the campus is at the end of the water distribution system without looping.

Therefore, iron and manganese laden sediment accumulates the piping and is drawn into the campus drinking water system. Res-Kem designed and constructed a filtration system to remove iron and manganese from the drinking water, as well as a storage tank. The volume of the tank is 150,000 gallons which provides two days of storage in the event of a water emergency with the water supply.


System Solution:

Inlet Iron and Manganese:	Average Inlet Iron 0.22 mg/l Average Inlet Manganese 0.11 mg/ml
Flow Operating Conditions:	Typical: 52 gpm typical
System Configuration:	Dual Parallel 36" diameter ASME Code, carbon steel tanks Epoxy Lined, NSF 61 certified Schedule 80 PVC face piping Differential Pressure Switch initiated backwash Greensand Plus filtration media
Control Valves:	Bray Series 31 valves with Bray Series 93 actuators
System Operation:	Differential Pressure Switch initiates backwash cycle
Added Features:	Domestic water booster pumping system brings filtered water backwash to system Sodium Hypochlorite (NaOCL) serves as the chemical oxidant for the removal of iron and manganese in the filtration system. The NaOCL will be injected immediately upstream on the system influent piping header. Chemical dose will flow paced based from the signal from the filtration systems influent flow meter.

For Additional Information:
Technical bulletin on Res-Kem's Greensand/Greensand Plus filters
Online catalog for Greensand Filter Systems
Technical bulletin on Greensand Plus filtration media for iron and manganese removal

Triple Greensand Plus Filter for Iron and Manganese Removal

A triple Greensand Plus filter for iron and manganese removal was assembled and shipped today. This skid-mounted system will be installed to treat the water for a small community water system in the Poconos operated by a large private water utility company.


The system operates in a parallel arrangement with three skid mounted, Greensand Plus filters with optional interconnecting piping and isolation valves. As specified, Bray butterfly valves with electric actuators are used. To match standard practice at the utility, a Modicon Premium PLC with Wonderware Windows CE operator interface panel will be used. Each tank is epoxy lined carbon steel with an epoxy exterior, 150 psi ASME code. Face piping consists of Schedule 40 black pipe and fittings. Regeneration initiated by either high differential pressure or timeclock.


As stated in a previous post, Greensand Plus iron and manganese removal media from Inversand replaces the discontinued Greensand filter media.