Microfiltration System Companies
MF providers covering particulate, pathogen, and pretreatment filtration for municipal and industrial flows.
40 specialist providers · 1 related · 12 countries
Qualified suppliers come to you.
Filter results
Country
Industry
Technology
Not sure where to start?
Showing 1-20 of 41
Specialists in microfiltration system
Providers whose services or self-declared specialties match this category.
Hikins (Jiangsu) Envirotech Co., Ltd.
China · 200+ employees
Hikins (Jiangsu) Envirotech Co., Ltd. is a leading manufacturer of water treatment components, specializing in advanced filtration and purification technologies. Serving the construction, manufacturing, and utilities sectors, Hikins provides innovative solutions for water treatment plants and systems across China and the Asia-Pacific region.
Buyer's guide
The buyer's guide to microfiltration system
Microfiltration System Design: Flux Rates, Integrity Testing, and Regulatory Compliance
Microfiltration (MF) systems for drinking water treatment use hollow fibre membranes (polyvinylidene fluoride PVDF, polyethersulphone PES, or polypropylene PP) with pore sizes of 0.1 to 0.4 microns. Hollow fibres operate in dead-end (outside-in or inside-out flow) or cross-flow mode. Flux rates for MF: 40 to 120 LMH instantaneous (net flux 30 to 80 LMH accounting for backwash downtime). Backwashing (reverse permeate flow, 1 to 3 bar, 30 to 90 seconds duration) restores flux every 15 to 60 minutes. Chemical enhanced backwash (CEB) using 50 to 200 mg per L sodium hypochlorite every 1 to 3 days removes persistent organic fouling that backwash alone cannot clear.
Integrity testing of MF/UF membranes is mandatory for systems receiving pathogen removal credit under US EPA LT2ESWTR. Pressure hold test (direct integrity test, DIT): pressurize membrane to 100 to 200 kPa air, hold for 5 minutes; pressure decay rate calculation (PDR) must not exceed 6.0 kPa per minute (US EPA Membrane Filtration Guidance Manual limit).
Each fibre defect above pore size allows detectable pressure decay. Turbidity monitoring (indirect integrity test): continuous turbidity of filtered water above 0.15 NTU triggers direct integrity test. Regulations require DIT at minimum daily for systems serving above 10,000 people; failing fibres are identified by sonic testing or visual inspection and pinned/plugged, module removed when too many fibres failed.
MF plant design for a 10 MLD drinking water plant: approximately 15 to 25 membrane modules (0.5 to 0.8 m diameter by 1.5 to 2.0 m long) containing 3,000 to 8,000 fibres per module, depending on membrane brand and fibre density. Installed membrane area: 3,000 to 5,000 m2. Skid arrangement in duty/standby pairs enables continuous production during backwash cycles and integrity testing.
Air scouring during backwash (0.3 to 0.6 Nm3 per m2 per hour) reduces fouling at fibre exterior. Capital cost for 10 MLD MF plant: $800,000 to $2,500,000. Chemical use: sodium hypochlorite for CEB and CIP, sodium hydroxide and citric acid or oxalic acid for periodic recovery CIP every 3 to 6 months. Membrane module replacement at 7 to 15 years.
Frequently asked questions
Does microfiltration remove viruses?
Microfiltration with pore sizes of 0.1 to 1.0 microns does not reliably remove viruses (0.02 to 0.3 microns nominal size), which are smaller than MF pore sizes. US EPA LT2ESWTR gives MF systems credit for 4-log Cryptosporidium removal and 3-log Giardia removal but zero log virus reduction credit unless supplemented with disinfection. To achieve 4-log virus reduction required for surface water systems, chlorination (Ct above 6 mg-min per L for 2-log, above 12 mg-min per L for 3-log Giardia/virus), UV (40 mJ per cm2 for 4-log virus), or ozonation is applied downstream of the MF. Ultrafiltration membranes with pore sizes below 0.02 microns are classified as having virus removal capability (2 to 4 log credit under LT2) and are preferred where a single-barrier membrane system is desired.
What is the lifespan of a microfiltration membrane?
MF hollow fibre membranes last 7 to 15 years under good operating conditions with proper chemical cleaning protocols. Key factors determining service life: chlorine exposure (PVDF membranes tolerate up to 500,000 mg per L-hr cumulative chlorine; exceeding this causes fibre embrittlement and increased breakage rate); oxidant exposure during CEB and CIP (balance between fouling removal effectiveness and cumulative oxidant damage); physical integrity (fibre breakage from excessive backwash pressure - never exceed manufacturer's maximum TMP specification of typically 1.5 to 2.5 bar); and temperature cycling (freeze-thaw cycles crack fibres if water freezes in the module - drain and protect in cold climates). End of life indicators: increasing CIP frequency to restore flux, broken fibre rate above 5 percent of total fibres per module, or pressure hold test failing even after physical inspection and fibre pinning.
What feedwater quality is needed for microfiltration?
MF membranes are relatively tolerant of feedwater turbidity (can handle 50 to 200 NTU with appropriate pretreatment or coagulation), but performance degrades with high biological activity (algae blooms), fine clay particles (colloidal silica, clays below 0.1 micron which pass through MF and cause downstream fouling), and high natural organic matter (NOM > 10 mg per L TOC causing irreversible fouling). Coagulation pretreatment (alum or ferric at 5 to 20 mg per L, rapid mix but without sedimentation - 'inline coagulation') ahead of MF improves NOM removal from 20 to 40 percent (MF alone) to 60 to 80 percent, reduces fouling rate, and improves colour removal. pH control to 6.5 to 7.5 optimises coagulation. Maximum inlet pressure: 2 to 5 bar depending on module design; system must include pressure relief to prevent membrane rupture from pump transients.
How are microfiltration systems disinfected and cleaned?
MF systems use three cleaning protocols: (1) Physical backwash - reverse permeate flow at 1.5 to 3 bar, 60 to 90 s, every 15 to 60 minutes (routine, no chemicals); (2) Chemical enhanced backwash (CEB) - backwash with 50 to 200 mg per L NaOCl solution, soak 5 to 15 minutes, then forward flush; for inorganic fouling (iron, manganese): 500 to 1,000 mg per L citric acid CEB; frequency: daily to weekly; (3) Clean-in-place (CIP) - alkaline stage (0.1 to 0.5 percent NaOH plus 200 to 1,000 mg per L NaOCl, circulate at 30 to 40 degrees C for 1 to 2 hours) followed by acid stage (0.2 percent citric acid or 0.1 percent oxalic acid, 30 to 40 degrees C, 1 hour) for inorganic scale. CIP frequency: every 3 to 6 months or when normalised flux falls below 80 percent of clean flux despite CEB. All chemical cleaning chemicals must be WRAS or NSF 60-approved for potable water contact.
Illustrative scenario · Municipal drinking water
A composite drawn from typical projects in this category, not a single client engagement. Figures are indicative.
- Challenge
- A UK water company operating a 20 MLD surface water treatment plant in the South West of England faced DWI requirements to install a physical Cryptosporidium barrier following a positive oocyst detection in treated water. The existing slow sand filter plus rapid gravity filter arrangement could not reliably achieve 4-log Cryptosporidium reduction at the post-spring-runoff peak turbidity events (up to 30 NTU raw water).
- Approach
- Installed a 20 MLD PVDF hollow fibre microfiltration plant (pore size 0.1 microns) in a retrofitted rapid gravity filter hall. Inline coagulation (alum 8 mg per L with polymer 0.2 mg per L) improved NOM and colour removal from 20 to 55 percent. Daily pressure hold direct integrity testing was implemented with automatic off-line response for failed modules. Integrity breaches above 0.025 bar per minute automatically triggered module isolation and DWI notification protocol.
- Outcome
- MF plant achieved 4-log Cryptosporidium removal credit confirmed by DWI following site verification. Filtered water turbidity below 0.08 NTU consistently through two spring runoff seasons. Zero positive Cryptosporidium samples in treated water over 30 months. DWI closed the regulatory correspondence and the plant was removed from the DWI Action Programme. Normalised flux decline rate averaged 1.2 percent per month over the first 18 months, consistent with the design expectation.
Questions to ask shortlisted providers
5
- 01
What PVDF fibre configuration do you propose (inside-out or outside-in flow), and what are the relative fouling resistance, fibre breakage resistance, and air scouring effectiveness trade-offs for our specific feed water?
Inside-out flow MF (feed inside the hollow fibre, permeate exits through the wall) provides better hydraulic control but is more susceptible to blockage by fibrous material. Outside-in flow (feed outside the fibre, permeate inside) tolerates higher TSS but requires effective air scouring to prevent cake accumulation on the fibre exterior. For high-turbidity surface water with seasonal algae, the outside-in configuration with effective coarse-bubble air scouring is generally preferred. Confirm the fibre configuration against your specific source water characteristics.
- 02
What is the design air scour volume (Nm3 per m2 per hour) and what evidence do you have that this is sufficient for your proposed flux to prevent irreversible cake formation?
Insufficient air scouring is the most common cause of premature MF membrane fouling. The air scour volume must be matched to the flux, MLSS (if post-biological treatment), and feed water fouling tendency. An air scour rate adequate for low-turbidity groundwater may be inadequate for high-TSS surface water. Ask for the air scour design basis (minimum air velocity in the riser duct, calculated for your specific fibre length and diameter) and evidence of performance at this air rate from reference installations.
- 03
What is the integrity of the proposed module-to-manifold connections, and how are integrity breaches at individual module or skid level isolated and reported?
In a large MF plant with multiple modules per skid and multiple skids, a single broken fibre or failed manifold seal can provide a direct bypass path around the membrane barrier. The control system must be capable of isolating individual module integrity failures automatically (based on DIT results) and alerting operators without requiring plant shutdown. Ask for the minimum detectable integrity defect size (in terms of number of fibres broken) for the proposed DIT configuration.
- 04
What is the chemical cleaning protocol and annual chemical consumption estimate, and are all cleaning chemicals DWI-approved for use in drinking water treatment?
Chemicals used in MF cleaning for drinking water production (sodium hypochlorite, citric acid, sodium hydroxide) must be DWI-approved (Regulation 31 list) or WRAS-approved. Some cleaning formulations use proprietary chemical blends with non-DWI-approved components. Ask for the DWI approval reference for each cleaning chemical and confirm that the dosing concentrations are within the approved range.
- 05
What is the backwash water volume and quality, and have you confirmed that the backwash return to head of works will not compromise the treatment train during high-turbidity events?
MF backwash water contains concentrated suspended solids (5 to 20 times the feed TSS), NOM, and coagulant floc. During high-raw-water-turbidity events, returning backwash water to the head of the works at full rate can overload the coagulation and clarification stages. Backwash surge management (storage tank, controlled return rate) is required for plants treating high-turbidity surface water. Confirm the backwash return protocol and its impact on hydraulic and treatment capacity.
What drives cost in this category
4
- Plant capacity and membrane area required
- A 5 MLD MF drinking water plant (PVDF hollow fibre, 60 LMH net flux) requires approximately 3,500 m2 of membrane area, at 12 to 18 GBP per m2 = 42,000 to 63,000 GBP in membranes. Total plant capital (including civil works in a new building, blowers, backwash pumps, CEB system, instrumentation, and commissioning): 1.5 to 4 million GBP. A 20 MLD plant scales to 5 to 14 million GBP total capital.
- Coagulation pretreatment requirement
- Inline coagulation before MF (no sedimentation) costs 30,000 to 80,000 GBP in capital (dosing pumps, chemical storage, rapid mixing) plus 0.05 to 0.20 GBP per m3 in chemical cost. Coagulation improves NOM removal from 15 to 25 percent (MF alone) to 55 to 75 percent, significantly improving water quality and reducing downstream chlorination DBP formation. Coagulation also reduces membrane fouling rate by 30 to 50 percent, extending membrane service life and reducing CEB chemical consumption.
- CEB and CIP chemical cost
- A 20 MLD MF plant using daily NaOCl CEB (100 mg per L, 3 minutes, 3 percent of feed volume) consumes approximately 600 kg of NaOCl (12 percent) per day = 220 tonnes per year at 150 GBP per tonne = 33,000 GBP per year. Quarterly acid CEB (citric acid) adds 5,000 to 15,000 GBP per year. Annual CIP (NaOH plus NaOCl alkaline stage, citric acid acid stage): 8,000 to 25,000 GBP per event. Total annual cleaning chemical cost for 20 MLD plant: 50,000 to 90,000 GBP.
- Regulatory DIT and monitoring cost
- Daily direct integrity testing (automated pressure hold) adds minimal operating cost (compressed air, automated valve actuation). However, failure of DIT triggers DWI notification, investigation, and potentially isolation of the non-compliant membrane vessel and production capacity reduction. For a plant sized to meet peak supply demand, loss of one skid (10 to 15 percent of total capacity) during DIT investigation may require emergency supply restrictions or tankered supply, costing 5,000 to 50,000 GBP per event depending on duration and supply zone size.
Key regulations and standards
4
- UK Cryptosporidium Regulations 1999 and DWI Technical Guidance
- The Water Supply (Water Quality) (Amendment) Regulations 1999 require water companies in England and Wales to monitor all large surface water treatment works for Cryptosporidium in source and treated water. Where source water Cryptosporidium concentrations or risk assessment indicates significant risk, DWI requires installation of a treatment process capable of achieving 4-log Cryptosporidium removal. MF and UF membrane systems meeting DWI integrity testing requirements are the accepted technology standard for achieving this barrier.
- DWI List of Approved Products: MF Membranes and Cleaning Chemicals
- Microfiltration membranes and all cleaning chemicals used in drinking water treatment must be listed on the DWI Regulation 31 List of Approved Products or hold WRAS approval. DWI evaluates membrane products for extractable contaminants, biocidal properties, and conformance with BS EN 14652. Cleaning chemicals (hypochlorite, citric acid, NaOH) must be food-grade or DWI-approved for drinking water contact at the concentrations used. Proposals using non-approved products require pre-clearance with DWI before installation.
- WRAS: Backwash Water Return to Supply System
- MF backwash water returned to the head of the treatment works or to a recovery lagoon must not compromise the potable water supply quality. WRAS regulations prohibit cross-connections between non-potable (backwash return) and potable water circuits without appropriate backflow prevention (Type CA or AA air gap per BS EN 1717). Backwash water quality monitoring (Cryptosporidium, turbidity) is required if the backwash return arrangement creates any potential for contamination of the main supply.
- Environmental Permitting Regulations 2016: MF Waste Sludge Disposal
- MF filter solids (backwash sludge from drinking water treatment) are classified as waste under EPR 2016 if removed from the works for disposal. Where coagulants (aluminium sulphate, ferric sulphate) are used, the sludge is an aluminium or iron hydroxide sludge; this is non-hazardous but must be managed under a waste exemption or permit. Disposal to municipal sewer requires trade effluent consent if solids concentration is above consent limits. Land application of dewatered aluminium sludge is permitted under relevant EA exemptions where quantities are below threshold.
From the Insider