PRODUCTS: Ion exchanger system Reverse osmosis system Industrial selective exchanger

Ion exchanger system, demineralization system, demineralization cartridge, ion exchanger, reverse osmosis system, electrodeionization, chemical-physical waste water system, selective exchanger system from Decker for industry/commerce.

Ion exchanger system

An ion exchanger system or IAT system is used to recirculate industrially contaminated rinsing water in order to remove ionogenic
contaminants (e.g. heavy metals, alkaline earth metals) from this water and return the water to the water cycle. This reduces the production of avoidable wastewater, prevents the quality-impairing salination of the circulation water and complies with the regulatory requirements for the operation of the system.

A common application for an ion exchanger system is the circulation of rinsing water contaminated with heavy metals in aqueous processes such as electroplating or industrial parts washing machines (non-textile). In particular, carryover (concentrations < 10 mval/l) from upstream process steps are enriched in a bath with demineralized water, which is continuously cleaned by the ion exchanger system. Depending on the application, the circulation system consists of one or two lines, each with a strongly acidic cation exchanger, so-called SAC (sulphonic acid exchanger on styrene-divinylbenzene copolymer), a weakly basic exchanger, so-called WBA (tertiary amine exchanger on styrene-divinylbenzene copolymer) resp. also so-called “medium basic” exchanger, and possibly a strongly basic anion exchanger, so-called SBA (quaternary amine exchanger on styrene-divinylbenzene copolymer). In applications that require a low conductivity value, a mixture of a strongly acidic and a strongly alkaline exchanger is additionaly switched downstream for external ion exchanger regeneration so-called mixed bed resin or mixed bed exchanger, which can achieve a conductance value of less than 0.1 µS/cm up to the lowest technically achievable conductance value of 0.056 µS/cm or 18.2 MΩ-cm under optimum conditions.

Furthermore, depending on the application, physical pre-filtration of the ion exchanger system using a gravel filter or multi-layer filter, denaturation of any interfering biology using UV light and separate post-filtration and/or removal of apolar or non-ionic substances using activated carbon or a scavenger resin as an exchange unit is carried out.

Ion exchanger systems

Ion exchangers and filter media

Ion exchangersor ion exchange resins are spherical granules, similar in appearance to sand, which carry out an ion exchange process in an aqueous solution, i.e. they can remove ions and release the ions with which they were previously loaded, i.e. “conditioned”. Depending on the type of ion exchange resin, the effect is that the aqueous solution, e.g. city water, circulating water or waste water, is purified of the unwanted ions it previously contained.

The packaging units for ion exchanger resins are usually 25L bags, 1000L = 40 bags on pallets or 1000L big bags. Ion exchangers often exist in a gel form for simple applications such as city water desalination and in a macroporous, more reactive form for more complex applications.

Ion exchangers or ion exchanger resin are usually used in pressure housings with pre-filtration, e.g. a multi-layer filter, gravel or sand filter, cartridge or pleated filter. Depending on the contamination of the input water, further purification steps such as activated carbon, scavanger resins for surfactant removal or biological denaturation, e.g. by UV, may also be necessary, e.g. to reduce permanent inactivation of the resins by mineral oils or to prevent biological contamination. In selective exchangers, pH adjustment can help to maintain function and optimize capacity.

Depending on the application, ion exchanger resin can be used directly from the delivery container or requires separate activation. For this purpose, the resins are removed from the delivery container (25L PE bag or big bag), pre-cleaned if necessary and converted into the desired working form (e.g. Na form, Ca form, K form, NH4 form, Fe3+, Al3+ form or OH-, NH3-, or Cl-form). This process also removes production-related impurities that would otherwise be introduced into the process. Regeneration before use is therefore always recommended.

Ion exchanger resin SAC Lewatit SP112

Selective exchanger system, SAT system

A selective exchanger system or SAT system is used as a police filter in an industrial chemical-physical wastewater system (CP system) in the final filtration after precipitation/flocculation or, for example, in groundwater remediation in order to keep regulatory relevant residual heavy metal contents in the wastewater below the required monitoring value.

A typical application for a selective exchanger system is the so-called police filter after chemical-physical wastewater treatment in metalworking companies that discharge indirectly into a municipal wastewater treatment plant. According to Annex 40 of the Wastewater Ordinance, the parameters subject to monitoring for indirect discharge are generally 0.5 mg/L nickel and 0.5 mg/L copper, for example. As part of CP wastewater treatment, e.g. by means of hydroxide precipitation and flocculation via a polymer and/or a bentonite, the heavy metals are precipitated to a residual content of a few mg/L. In this area, it makes economic sense to use an IDE selective exchanger such as Purolite S930 Plus to achieve the legal limits by means of ion exchange against sodium, for example.

Another application is the targeted removal of foreign substances from process solutions, e.g. the removal of foreign metal ions (Cu, Ni, possibly Fe(III)) from a process solution for chromium deposition based on Cr(III) salts.

Furthermore, depending on the application of the selective exchanger system, a (physical) pre-filtration by means of a gravel filter or multi-layer filter and a pH adjustment in the inlet and outlet of the ion exchanger is carried out in order to optimize the feed parameters for the selective ion exchanger for heavy metal separation. In addition, any interfering biology can be denatured using UV light and separate post-filtration and/or apolar or non-ionic substances (in particular mineral oils) can be removed using activated carbon or a scavenger resin as an exchange unit. In rare cases, further filter stages with separate filter material may be required, e.g. a strongly basic anion exchanger to remove anionic complexes or anionic compounds (e.g. PFC) or a further ionogenic filter material.

Selective exchanger systems

Demineralization system, VE-system

A demineralization system or VE-system is used to produce so-called demineralized water (VE-water). In this process, all ionogenic substances (usually salts and dissolved gases such as carbon dioxide) are removed from the input water, often city water, and replaced with H2O. This produces highly pure demineralized water (also known as demineralized water, DM water or “forklift water” or “battery water”) for industrial purposes.

A common application for the demineralization system is the production of demineralized water with a demineralization system, e.g. in an electroplating plant with a conductivity of < 20 µS/cm salt load from city water. Depending on the requirements, the VE-system consists of one or two lines, each with a strongly acidic cation exchanger, so-called SAC (sulphonic acid exchanger on styrene-divinylbenzene copolymer) and a strongly basic anion exchanger, so-called SBA (quaternary amine exchanger on styrene-divinylbenzene copolymer). In applications that require an even lower conductance value, a mixture of a strongly acidic and a strongly basic exchanger is additionally connected downstream for external regeneration, so-called mixed bed resin or mixed bed exchanger, which can achieve a conductance value of less than 0.1 µS/cm up to the lowest technically achievable conductance value of 0.056 µS/cm or 18.2 MΩ-cm under optimum conditions.

The system can also be optimized for lower regeneration chemical consumption by adding further ion exchanger stages, e.g. weakly acidic cation exchangers and weakly basic anion exchangers.

Furthermore, depending on the application for a demineralization system or VE-system, physical pre-filtration is carried out using a gravel filter or multi-layer filter or filter cartridges, denaturation of any interfering biology using UV light and/or removal of apolar or non-ionic substances using activated carbon or a scavenger resin as an exchange unit.

Demineralization system

Demineralization cartridge, VE cartridge

A demineralization cartridge or VE-cartridge is used to produce demineralized water in small quantities of up to 4 m³/week. In this process, all ionogenic substances are removed from the input water, often city water, and replaced with H2O. This produces highly pure demineralized water (also known as DM water or “forklift water” or “battery water”) for industrial purposes with a conductivity of < 0.1 µS/cm.

A common application for a demineralization cartridge is the production of demineralized water, e.g. in an industrial or commercial plant for diluting concentrates, preparing chemical baths or rinsing sensitive parts with a conductance of < 30 µS/cm salt load from city water or the filling of forklift batteries (according to ZVEI (Association of the Electrical and Digital Industry) leaflet requirements for electrolyte and refill water for lead batteries). The VE cartridge consists of a mixed bed resin, e.g. Lewatit NM 60 or Purolite MB400, with a proportion each of strongly acidic cation exchanger, so-called SAC (sulphonic acid exchanger on styrene-divinylbenzene copolymer) and a strongly basic anion exchanger, so-called SBA (quaternary amine exchanger on styrene-divinylbenzene copolymer).
In order to prevent only weakly bound ions such as chlorides, hydrogen carbonate or silicates from breaking through in a demineralization cartridge, two demineralization cartridges are often connected in series. The first cartridge is equipped with a conductivity measurement in the outlet. As soon as the conductance rises, silicic acid and chlorides have already broken through, but these are not absorbed by the 2nd VE cartridge. A carousel exchange takes place in which the first cartridge is removed for regeneration and the second cartridge is placed in the leading position and an optional 3rd cartridge takes over the further post-cleaning.

In special applications, the mixed bed resin used can be replaced by a so-called UPW Ultra Pure Water resin, e.g. Amberjet UP6040 or Lewatit UP 1292 MD. This is characterized by higher networking and a higher capacity. Under optimum conditions, such a VE-cartridge can purify the water to the lowest technically achievable conductivity value of 0.056 µS/cm or 18.2 MΩ-cm. In the context of ion exchanger regeneration, however, it should be noted that this is not a pool regeneration, but a proprietary regeneration in order to avoid cross-contamination with other resins that may have poorer properties.

VE cartridges

Industrial reverse osmosis system, UO system

An industrial reverse osmosis system or UO system is used in the same way as a VE-system to produce demineralized water. The input water, often city water, is softened or hardness-stabilized and applied to a membrane under high pressure to produce a pure demineralized water for industrial purposes, known as permeate, and a saline wastewater, known as concentrate.

A common application for the industrial reverse osmosis system is the production of demineralized water in a surface treatment plant with a conductivity of < 20 µS/cm salt load. The UO system consists of a system separator, a 100 µm pre-filter, a duplex softening system with one strongly acidic cation exchanger in the Na form, so-called SAC (sulphonic acid exchanger on styrene-divinylbenzene copolymer) and NaCl regeneration. The high-pressure pump increases the pressure from at least 2 bar to 14 bar on the 120 µm thick polyethersulfone layer of the semi-permeable membrane and thus performs a temperature-dependent separation of the feed into permeate and concentrate. However, the resulting demineralized water differs from the demineralized water of an ion exchanger system in that the ion retention on the anion side depends on the respective ion: ammonium ~92%, nitrate ~85%, fluoride ~95%, silicate ~90%, sulphate ~97%.
An industrial reverse osmosis system can be expanded by additional filtration stages depending on requirements. Gases dissolved in the feed stream (CO2) may be converted into HCO3 in advance by pH adjustment and separated at the membrane or by means of downstream membrane degassing. A further reduction of the conductivity value down to the technically lowest achievable conductivity value of 0.056 µS/cm or 18.2 MΩ-cm can be achieved without a wastewater system, e.g. by a downstream demineralization cartridge, VE-cartridge, with mixed bed as exchange cartridges for external ion exchanger regeneration or EDI system(electrodeionization) for continuous purification. The membranes installed in the system can be chemically and thermally cleaned using an optional cleaning system (for larger systems). The RO system can also be designed as permeate-staged, i.e. two reverse osmosis membranes in series in the permeate for a special purification of the demineralized water up to 99.5% of the input water or concentrate-staged, i.e. two reverse osmosis membranes in series in the concentrate for a particularly low amount of wastewater. In the event of changing inlet pressure or fluctuating delivery quantities, storage tanks with pumping stations may be required.

An electrodeionization system can be installed downstream of a reverse osmosis system to produce ultrapure water.

Reverse osmosis system

Electrodeionization, EDI systems for ultrapure water production downstream of a reverse osmosis system

Electrodeionization (EDI systems) is usually connected downstream of a reverse osmosis system in order to produce from the deionized water produced there (so-called permeate) the even purer ultrapure water up to a conductivity of 0.056 µS/cm or 18.18 MΩ-cm (so-called diluate).

A typical application for electrodeionization is the production of ultrapure water for semiconductor production or hydrogen production.
Electrodeionization is not operational on its own, but always requires appropriate pretreatment via prefiltration, hardness removal or hardness stabilization and, if necessary, a single or double (permeate-staged) reverse osmosis system. In addition, dissolved gases must be removed and, due to the constant operating requirements of electrodeionization, a separately secured tank with an ultrapure water circuit is generally also required.
Reverse osmosis system

Chemical-physical wastewater treatment system, CP plants for industry

An industrial chemical-physical wastewater treatment system is used for the chemical-physical (CP) treatment of wastewater generated in an industrial plant in order to meet the regulatory requirements for the discharge of wastewater into a body of water or a municipal wastewater treatment plant.

Industrial plants are generally assigned to one of the industrial sectors listed in an annex of the Wastewater Ordinance (e.g. Annex 40 for metal processing companies) and, depending on the type of discharge, must treat the wastewater directly into a body of water or indirectly into the municipal wastewater treatment plant, usually by means of a chemical-physical wastewater treatment system . For direct dischargers, Part C of the respective Annex applies; for indirect dischargers, the statutes of the municipal wastewater treatment plant apply instead.
With regard to the approved parameters, the chemical-physical wastewater treatment plant is operated. For example, a chromium(VI) batch is detoxified separately by reducing the batch to chromium(III) at < pH 2.5 (temperature-compensated) using the reducing agent sodium bisulphite, whereby the pH value is stabilized. The chromium(III) is then transferred in a batch treatment, if necessary together with other partial streams containing metal salts, in a hydroxide precipitation with the addition of e.g. flocculation polymer and bentonites into a sedimentation-capable precipitation product and, if necessary, concentrated in a sludge thickener. The solid/liquid separation takes place in the batch via a chamber filter press or a belt filter after the clear water has been removed if necessary. The aqueous phase is pumped through a multi-layer filter to a selective exchanger with an IDE ion exchanger resin such as Lewatit TP 207 in order to comply with the discharge monitoring values of the regulatory requirements. Equipment for pH adjustment may be installed upstream and/or downstream of the selective exchanger.

The CP wastewater system can be modularly supplemented with further filter stages, such as activated carbon, an additional iron oxide/hydroxide filter stage or a further anionic selective exchanger to remove any organics, complexes or PFCs. The wastewater system can also be expanded to include disinfection steps, oxidation steps or rinsing steps. Depending on the size of the system, the selective exchangers are equipped with equipment for regeneration/conditioning on site or are regenerated in the central regeneration station in 92348 Berg. If there are non-treatable partial flows in wastewater systems, these can be selectively fed to an evaporation process.

The sensor design can be analog or digital, e.g. using Memosens sensors.

Industrial wastewater system