Iron and Manganese Removal Filter

DMI-65 is a catalytic filter media boosting oxidation capacity of low cost oxidant such as NaOCl. It is necessary to inject chlorine before the filter to activate the filter.

The DMI-65 is one of the fewer catalytic water filtration media’s in the world developed to remove iron and manganese that is certified to NSF/ANSI 61 for drinking water applications.

Iron and Manganese
Iron can be removed by many different methods to achieve a certain level. These methods are regarded as old technology in world standard, expensive in chemical and labor costs, energy and ongoing costs and Maintenance costs.

Manganese however is much more difficult to remove and expensive using traditional methods.

The DMI-65 is the most sophisticated catalytic reaction media in the world and has a very high ability in removing iron and manganese. The DMI-65 will also remove arsenic from a water supply given the correct conditions.

The DMI-65 is the lowest cost method of removing Iron – Manganese from a water supply. All other processes are expensive to operate and difficult to maintain. The DMI-65 has a life span of at least 5 years before needing to be replaced if the plant is maintained correctly.

Catalytic Filter Media
Iron and manganese in solution are in the form of lower valence oxi-hydroxides (example, ferrous hydroxide). Higher valence oxi-hydroxides (ferric hydroxide, red color) are not soluble in water around neutral pH. When the water with iron and manganese in solution and oxidant reaches the filter bed, the low valence hydroxides oxidize to high valence; insoluble form and precipitated particles are retained in the filter bed. This process would take place normally in a matter of days to weeks. The catalytic media makes the reaction to take place in minutes accelerating the reaction a few hundred times.

The DMI-65 is a similar filtration media to other iron and manganese removal media, however the DMI-65 does not need to be regenerated.

Comparison of Different Disinfection Technologies

CHLORINATION

Advantages:

- Lower capital cost needed

- Residual persists in the water for an extended period of time. This feature allows the chlorine to travel through the water supply system.

- More suitable for system wherein residual disinfectant is needed.

- Good color removal

- Can also be used to oxidize iron bacteria in water, but with sufficient contact time.

Disadvantages:

- Reacts with naturally occurring organic compounds found in the water supply to produce dangerous compounds, known as disinfection byproducts (DBPs). The most common DBPs are trihalomethanes (THMs) and haloacetic acids.

- Hazardous upon contact

- May raise concern on odor and tastes.

- Can cuase corrosion on metal parts and equipment

OZONATION

Advantages:

- Effective in removing viruses and bacteria

- No harmful by-products are formed; unlikely to form carcinogens

- influences pH and temperature minimally on a broad spectrum.

- Higher oxidation potential than chlorine

- No remaining tastes or odors after treatment

Disadvantages:

- Ozone is less suitable for maintenance of a residual concentration (secondary disinfectant), causing it to decompose in water relatively quickly

- solubility decreases when temperatures rise

- High capital cost

- May result in corrosion of metal parts and equipment

UV DISINFECTION:

Advantages

- Effective in removing viruses and bacteria

- No harmful by-products are formed; unlikely to form carcinogens

- No remaining tastes or odors after treatment

- Does not corrode metal equipment

Disadvantages:

- Not suitable for maintenance of a residual concentration (secondary disinfectant)

- Good only for point-of-use applications

MEMBRANE BIOREACTOR: APPLICATION OF MEMBRANE TECHNOLOGY IN WASTEWATER TREATMENT

Why do industrial plants treat their waste water? There are few important reasons:

• Conservation of natural resources


• Compliance to environmental laws

• Financial benefits

Before we go the the main topic, let us first look at the stages of a conventional waste water treatment facility:

Preliminary Treatment

It may be a physical or mechanical process which aims to remove large or coarse particles

Examples: Screens; grit chambers


Primary Treatment

A physical or mechanical process which removes Settleable Solids, Oil and Grease and about 40% of TSS and BOD

Examples: Sedimentation (primary clarifier); oil/water separator; aeration


Secondary Treatment

Physical, Biological and/or Chemical process; process to convert Dissolved Solids and Suspended Solids into a form that can be removed by physical means; removes up to 85% of TSS and BOD and a small percentage of TDS.

Examples: Sequencing Batch Reactor; Activated Sludge; Rotating Biological Contactor; Trickling Filter; chemical precipitation; flocculation; coagulation


Tertiary/Advanced Treatment

Any level of treatment, may be physical or chemical, beyond the secondary treatment focusing on the removal of nutrients and disease-causing microorganisms

Examples: Filtration; Ammonia Stripping; pH adjustment; disinfection using chemical, UV light or ozone

To understand the revolutionary potential of Membrane Bioreactor (MBR) Technology it is helpful to first consider how a conventional wastewater treatment plant operates. Each conventional plant consists of three basic parts:

This treatment process is 85-95 percent effective in removing TSS, BOD and COD but is often ineffective in terms of removing microorganisms.

Typically the discharge from a conventional plant will contain 10,000 to 100,000 microbes per milliliter.

Membrane Bioreactors, simply called MBRs offer an optimum solution:

• Membrane modules are submerged in the activated sludge to combine the biological step and the solid-liquid separation step into a single process.

• Essentially, membrane bioreactors replace the solids separation function of secondary clarifiers and sand filters in a conventional activated sludge system


• Produces effluent with much better quality than that produced by a conventional plant

Since the membrane acts as a barrier to microorganisms, the effluent quality is much better than that produced by a conventional plant. Also, the membrane barrier eliminates the need for secondary clarifier and allows the activated sludge to be more highly concentrated. This reduces the capacity needed for biological tanks, saving space and money.

MBR Plant can be configured either as internal/submerged, or external/sidestream.

• Internal/Submerged is the type where the membranes are immersed in and integral to the biological reactor


• External/Sidestream is where membranes are a separate unit process requiring an intermediate pumping step

Advantages of MBR Technology versus conventional process:

• Improved Water Quality - it meets stringent effluent requirements and filters out nearly all solids


• Allows Wastewater Reuse - as part of a treatment scheme, provides water for potable reuse; reduces wastewater discharge fees; provides water for non-potable applications where fresh water is in short supply


• Lowers Capital Costs - that is, Clarifier is not needed and biological step can be scaled down since bacteria concentration is higher


• Reduces Plant Space Requirements - Footprint is up to 50% smaller than conventional plant. It allows for easy expansion in terms of capacity within existing buildings


• Fewer Operational Problems - Bulking and floating sludge problems are minimized


• Easily Retrofittable to Existing MBRs and conventional WWTF - the system has few module connections and there is little need to modify infrastructure
  
  

Membrane Technology: Emerging Technology in Water Purification

Membrane Technology a generic term for a number of different, very characteristic separation processes. These processes are of the same kind, because all of these use semi-permeable membrane. It works without addition of chemicals and with low energy use. Separation process based on the presence of a semi-permeable membrane.

Membrane acts as a very specific filter that will let water flow through, while it catches suspended solids and other substances.

Benefits of Membrane Technologies over Existing Water Purification Methods

• Process can take place while temperatures are low


• Uses smaller space requirements (footprint); membrane equipment requires 90 to 95% less space than conventional plants


• Most of the energy that is required is used to pump liquids through the membrane, therefore, there is lower energy costs


• The process can easily be upgraded or expanded

MEMBRANE TECHNOLOGIES

Reverse Osmosis

A high-pressure, cross flow process, which separates dissolved solids from water through the use of a semi-permeable membrane.

In Osmosis, water flows from a column with low dissolved solids content to a column with a high dissolved solids content to attain equilibrium. Osmotic pressure is the pressure that is used to stop the water from flowing through the membrane, in order to create balance. By pursuing pressure that exceeds the osmotic pressure, the water flow will be reversed; water flows from the column with a high dissolved solids content to the column with a low dissolved solids content; thus the term Reverse Osmosis.

Nanofiltration

Nanofiltration is a pressure-related process, however, feed pressure is generally lower compared to RO Systems.

Process is the same as reverse osmosis in terms of concept and operation. However, while Reverse Osmosis removes the monovalent ions at 98-99% level at 200 psi, Nanofiltration membranes’ removal of monovalent ions varies between 50% to 90% depending on the material and manufacture of the membrane.

Microfiltration

MICROFILTERS membranes with pore size ranging from 0.1 to 10 microns. Microfiltration is a low pressure (10-100 psig) process for separating larger size solutes from aqueous solutions by means of a semi-permeable membrane. It removes bacteria and partially filters out viruses.

Ultrafiltration

Utilize filter membranes with pore size ranging from 0.005 to 0.1 micron. It is a low pressure (5-150 psig) process for separating larger size solutes from aqueous solutions by means of a semi-permeable membrane. Removes suspended solids, colloidal particles, bacteria and viruses and retains oils, particulate matter, bacteria and suspended solids, macromolecules and proteins.