Stacked horizontal RO-type pressure vessels and headers, used as an industry or equipment reference. Process selection depends on water quality and project conditions.
Your process challenges
Chemistry matched to real operating conditions.
Protect the intended membrane process by separating pretreatment, scale inhibition, cleaning and maintenance requirements.
Treatment approach
RO Pretreatment & Dechlorination: understand the treatment stages first.
Evaluate upstream clarification / filtration, residual-chlorine control and membrane scale inhibition separately. Assess membrane-feed quality rather than assuming that pretreatment is complete from a photograph of an RO skid.
Check together during selection
Use the membrane model and manufacturer's procedures to distinguish pretreatment, online maintenance and offline cleaning, and assess residuals and compatibility.
Compare candidate products below by treatment objective. Evaluate different routes separately; the list does not imply simultaneous dosing.
RO Pretreatment & Dechlorination: match requirements to each treatment stage.
Compare treatment objectives, chemical functions and verification criteria stage by stage. Products in the table may be alternatives or serve different stages; they are not necessarily dosed together.
Define influent and objectives first
Share complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals. This helps address pretreatment, membrane protection and maintenance requirements and narrow the product and specification range.
Then confirm assessment limits
Use the membrane model and manufacturer procedure to distinguish pretreatment, online maintenance and offline cleaning, and assess residuals and compatibility.
Compare all treatment routesProduct roles, conditions and verification
RO Pretreatment & Dechlorination: treatment objectives and product routes
Coagulant suitability depends on pretreatment, downstream filtration and membrane-manufacturer requirements. Polymer carryover may foul or affect RO membranes.
View each product's function and conditions
Polyaluminium Chloride
Function:Inorganic salt coagulation creates separable particles and affects downstream sludge production and alkalinity demand. Conditions:Compare pH, alkalinity, effective metal content and representative coagulation trials. Ferrous salts also require defined oxidation and downstream separation conditions. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Ferric Chloride
Function:Inorganic salt coagulation creates separable particles and affects downstream sludge production and alkalinity demand. Conditions:Compare pH, alkalinity, effective metal content and representative coagulation trials. Ferrous salts also require defined oxidation and downstream separation conditions. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Poly(diallyldimethylammonium Chloride)
Function:An organic coagulant option that destabilizes colloids before further flocculation and solid–liquid separation. Conditions:Define the sample's charge demand, intended use and downstream process. A polymer name alone does not establish dosage or grade. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Polyamine Coagulant
Function:An organic coagulant option that destabilizes colloids before further flocculation and solid–liquid separation. Conditions:Define the sample's charge demand, intended use and downstream process. A polymer name alone does not establish dosage or grade. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Polyacrylamide
Function:Polymer bridging and charge effects help build separable flocs. Flocculation does not remove dissolved salts or all COD. Conditions:Define particle and sludge properties, and match preparation, shear and settling/flotation/dewatering trials to the selected grade. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Sand / Anthracite Filtration Media
Function:Provides particle filtration or adsorption as a separate barrier for membrane-feed protection. Conditions:Select against filter-bed structure, particle load, pressure differential and adsorption objectives. Media do not replace a coagulant or membrane antiscalant. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Granular Activated Carbon
Function:Provides particle filtration or adsorption as a separate barrier for membrane-feed protection. Conditions:Select against filter-bed structure, particle load, pressure differential and adsorption objectives. Media do not replace a coagulant or membrane antiscalant. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
View product-specific checks
Polyaluminium Chloride
RO Pretreatment & Dechlorination: Al₂O₃ content; Basicity; Insoluble matter; pH test conditions; Impurity limits for the intended use; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Ferric Chloride
RO Pretreatment & Dechlorination: Effective iron content; Free acid; Impurities; Form & trial results; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Poly(diallyldimethylammonium Chloride)
RO Pretreatment & Dechlorination: Nominal concentration & test basis; Viscosity & test conditions; Residual monomer; pH; End-use documents; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Polyamine Coagulant
RO Pretreatment & Dechlorination: Composition; Active content & method; Viscosity test conditions; pH; Application trials; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Polyacrylamide
RO Pretreatment & Dechlorination: Ionic type & charge characteristics; Viscosity and test concentration/temperature; Residual monomer & test report; Dissolution conditions; Trial evaluation criteria; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Sand / Anthracite Filtration Media
RO Pretreatment & Dechlorination: Media composition; Particle size & grading; Treatment objective; Capacity or performance test conditions; End-use documents; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Granular Activated Carbon
RO Pretreatment & Dechlorination: Media composition; Particle size & grading; Treatment objective; Capacity or performance test conditions; End-use documents; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Compare results using representative water samples or site data, retaining the test methods and operating conditions.
Specify how the oxidant is measured, the treatment location, monitoring method and downstream use. Reducing agents are not automatically interchangeable.
View each product's function and conditions
Sodium Metabisulfite
Function:The corresponding reducing component controls measured residual chlorine or another specified residual oxidant. Conditions:Define the oxidant species and measurement basis, process location, downstream membrane/biological use and residual monitoring.
Sodium Thiosulfate
Function:The corresponding reducing component controls measured residual chlorine or another specified residual oxidant. Conditions:Define the oxidant species and measurement basis, process location, downstream membrane/biological use and residual monitoring.
Sodium Bisulfite
Function:The corresponding reducing component controls measured residual chlorine or another specified residual oxidant. Conditions:Define the oxidant species and measurement basis, process location, downstream membrane/biological use and residual monitoring.
Sodium Sulfite
Function:The corresponding reducing component controls measured residual chlorine or another specified residual oxidant. Conditions:Define the oxidant species and measurement basis, process location, downstream membrane/biological use and residual monitoring.
RO Pretreatment & Dechlorination: Pentahydrate/anhydrous basis; Content; Insoluble matter; Impurities; Reaction & monitoring conditions; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Sodium Bisulfite
RO Pretreatment & Dechlorination: Active reducing component; Solution content basis; Impurities; Monitoring & process conditions; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Sodium Sulfite
RO Pretreatment & Dechlorination: Salt form; Active components; Catalyst system; System temperature & end use; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Compare results using representative water samples or site data, retaining the test methods and operating conditions.
Review complete ion analysis, membrane model, recovery rate and concentrate scaling risk. Raw materials do not automatically qualify as membrane treatment formulations.
View each product's function and conditions
RO/NF Antiscalant
Function:A formulated RO/NF antiscalant candidate assessed against the actual feedwater, concentrate and recovery rate. Conditions:HEDP or ATMP raw material names and general cooling-water parameters do not replace validation of a formulation's suitability for the membrane system.
View product-specific checks
RO/NF Antiscalant
RO Pretreatment & Dechlorination: Complete water analysis; Recovery rate; Main scale-forming ions; Membrane model; Formulation & compatibility data; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Compare results using representative water samples or site data, retaining the test methods and operating conditions.
Need to compare these routes under your operating conditions?Share influent quality, treatment objectives and the existing process to discuss which products and conditions should be validated first.
Process & product matching
Select a treatment objective to explore suitable products.
Different treatment routes may apply. Open the matching notes for each product to review its role, conditions and purchasing criteria.
Use the membrane model and manufacturer procedure to distinguish pretreatment, online maintenance and offline cleaning, and assess residuals and compatibility.
For raw water and wastewater coagulation, compare active components, basicity and water-sample trials against clarification and phosphorus-removal requirements.
Why this matchesConditional option
Role
Inorganic salt coagulation creates separable particles and affects downstream sludge production and alkalinity demand.
Conditions
Compare pH, alkalinity, effective metal content and representative coagulation trials. Ferrous salts also require defined oxidation and downstream separation conditions. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Al₂O₃ content; Basicity; Insoluble matter; pH test conditions; Impurity limits for the intended use; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
An iron salt raw material for coagulation and chemical phosphorus removal, supporting clarification and sludge–water separation.
Why this matchesConditional option
Role
Inorganic salt coagulation creates separable particles and affects downstream sludge production and alkalinity demand.
Conditions
Compare pH, alkalinity, effective metal content and representative coagulation trials. Ferrous salts also require defined oxidation and downstream separation conditions. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Effective iron content; Free acid; Impurities; Form & trial results; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
An organic coagulating polymer for raw water, industrial water and suitable solid–liquid separation procedures.
Why this matchesConditional option
Role
An organic coagulant option that destabilizes colloids before further flocculation and solid–liquid separation.
Conditions
Define the sample's charge demand, intended use and downstream process. A polymer name alone does not establish dosage or grade. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Nominal concentration & test basis; Viscosity & test conditions; Residual monomer; pH; End-use documents; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
An organic coagulant option for colloid destabilization, clarification and separation in certain oily water systems.
Why this matchesConditional option
Role
An organic coagulant option that destabilizes colloids before further flocculation and solid–liquid separation.
Conditions
Define the sample's charge demand, intended use and downstream process. A polymer name alone does not establish dosage or grade. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Composition; Active content & method; Viscosity test conditions; pH; Application trials; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Select a suitable PAM for clarification, settling, thickening and sludge dewatering, matching flocculation behavior to the water, particles and equipment.
Why this matchesConditional option
Role
Polymer bridging and charge effects help build separable flocs. Flocculation does not remove dissolved salts or all COD.
Conditions
Define particle and sludge properties, and match preparation, shear and settling/flotation/dewatering trials to the selected grade. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Ionic type & charge characteristics; Viscosity and test concentration/temperature; Residual monomer & test report; Dissolution conditions; Trial evaluation criteria; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Sand, anthracite and other filtration materials for particle separation in raw water and industrial water.
Why this matchesConditional option
Role
Provides particle filtration or adsorption as a separate barrier for membrane-feed protection.
Conditions
Select against filter-bed structure, particle load, pressure differential and adsorption objectives. Media do not replace a coagulant or membrane antiscalant. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Media composition; Particle size & grading; Treatment objective; Capacity or performance test conditions; End-use documents; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Granular adsorption media for certain organic compounds, color, odor, taste, residual chlorine and specified contaminants.
Why this matchesConditional option
Role
Provides particle filtration or adsorption as a separate barrier for membrane-feed protection.
Conditions
Select against filter-bed structure, particle load, pressure differential and adsorption objectives. Media do not replace a coagulant or membrane antiscalant. When cationic polymers or flocculants enter membrane pretreatment, control residuals and verify compatibility with the membrane antiscalant.
Before purchase
RO Pretreatment & Dechlorination: Media composition; Particle size & grading; Treatment objective; Capacity or performance test conditions; End-use documents; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
A sulfite raw material for suitable dechlorination and industrial oxygen-scavenging procedures.
Why this matchesConditional option
Role
The corresponding reducing component controls measured residual chlorine or another specified residual oxidant.
Conditions
Define the oxidant species and measurement basis, process location, downstream membrane/biological use and residual monitoring.
Before purchase
RO Pretreatment & Dechlorination: Salt form; Active components; Catalyst system; System temperature & end use; Consider complete water analysis, membrane model, pretreatment flow, oxidant measurement basis, recovery rate and current chemicals.
Industry references describe general uses. Product specifications, certifications and application results require the corresponding supplier documentation.
PURCHASING QUESTIONS
More questions, answered.
How should I select water-treatment products for RO Pretreatment & Dechlorination?
Treat membrane-feed particles, residual chlorine and scaling risk separately to distinguish purchasing requirements for coagulants, dechlorination chemicals and antiscalants.
What information helps select products for this application?
Complete feed analysis, membrane model, pretreatment, oxidant measurements, recovery and current chemicals.
How are the suitable product and grade confirmed?
Use the membrane model and manufacturer procedure to distinguish pretreatment, online maintenance and offline cleaning, and assess residuals and compatibility. No universal dose or treatment result is implied. Product options may serve primary, supporting, conditional or alternative roles.
ENVO CHEMICAL
Discuss your water treatment needs
Share your application, current product or purchasing requirements to discuss a suitable supply option.
Selection, purchasing & documentsShare what you know
Specialty formulations
