UF/RO Fouling Bottlenecks and the Selective-Treatment Idea
Per the source: growing freshwater pressure in the Netherlands pushes the water-intensive pulp and paper sector toward reuse, but conventional end-of-pipe UF+RO trains, while reliable, remain sensitive to fouling, scaling and variable intake quality. The alternative tested: a more selective, flexible train of hollow-fibre nanofiltration (HFNF), granular activated carbon (GAC) polishing and electrodialysis reversal (EDR), run for 180 days on full-scale wastewater at the Industriewater Eerbeek IWE WWTP.
Engineering implication (analysis): NF handles organics and divalent salts while EDR owns desalination - decoupling organics removal from salt removal is precisely what avoids the compounding of scaling and organic fouling that kills RO trains.
180-Day Pilot Data: Colour/COD/Sulphate and 99th-Percentile Compliance
Per the source: HFNF achieved high removal of colour, COD and sulphate; EDR showed great flexibility in desalination; and reuse water met all paper-mill specifications at the 99th percentile - all parameters, 99% of the time.
Publication (per the source): Water Science and Technology 94(2026)3, pp. 319-337, DOI 10.2166/wst.2026.275, Schrijer et al., open access.
Engineering implication (analysis): for industrial reuse, 99th-percentile full-spec compliance is far stricter than an average - it holds the mill's process floor even under raw-water swings combined with membrane ageing. Chinese park-water supply agreements should adopt this compliance percentile directly in place of common monthly-average targets.
Brine Segregation: HFNF Concentrate Recycle, EDR Brine Re-Concentration
Per the source: selective treatment splits the concentrate into two chemically different streams - organic-rich HFNF concentrate and salt-rich EDR brine. The HFNF concentrate is treated by coagulation/flocculation and recirculated over the WWTP; the EDR brine is further concentrated for dedicated brine-management research.
Engineering implication (analysis): segregation lets each stream go where it can be treated - organics to the bioreactor, salts to crystallization/disposal - avoiding the classic ZLD failure mode of mixed brine that is simultaneously too salty for biology and too dirty for crystallizers.
TOTEX Audit: 1.85 vs 2.14 EUR/m3
Per the source: the techno-economic comparison lands at 1.85 EUR/m3 total expenditure for the innovative train versus 2.14 EUR/m3 for the conventional system - roughly 13.6% lower.
Engineering implication (analysis): the gap comes from on-demand desalination (EDR power scales near-linearly with salt load while RO must run full pressure) and HFNF's lower operating pressure versus RO. Note the European energy, labour and construction cost basis (paper's own scope) - domestic projects must be re-costed locally; but the qualitative conclusions - NF+EDR rides intake swings better and brine segregation works - are price-independent.
Mapping to Chinese Standards and Adoption Advice
China mapping (analysis): paper mills are prime users of industrial reclaimed water under GB/T 19923, with system boundaries per GB 50335-2016. Mills' sensitive parameters are hardness, suspended solids/colour and microbiological slimes - exactly the colour/COD/sulphate removals demonstrated here for recycled-fibre mills.
Adoption advice (analysis): write the 99th-percentile clause into park water-supply contracts; for EDR in hard, sulphate-rich regions (typical of North China parks), electrode scaling and electrodialysate maintenance dominate OPEX - pilot through both winter and summer intake temperatures before pricing. Cap the HFNF-concentrate recirculation ratio against the WWTP's actual biological load headroom so recirculated organics do not accumulate in a loop.