SJRA launches $1.3m membrane replacement and capacity programme
San Jacinto River Authority, Texas · Meeting date: October 22, 2026 · Published: October 23, 2026
San Jacinto River Authority has commissioned Plummer Associates to stress-test treatment processes at its 30mgd GRP Surface Water Treatment Plant as its 2015-vintage microfiltration membranes near the end of their useful life. The work is intended to establish a replacement strategy while testing for capacity gains across pretreatment, membranes and granular activated carbon.
Key points
- The board approved a professional services agreement with Plummer Associates worth up to $1.304 million, comprising $966,000 lump-sum work and $338,000 for cost-plus tasks.
- Phase 1 concluded that the plant's existing microfiltration membranes have an estimated three to five years of useful life remaining under current operating conditions.
- Phase 2 will test individual treatment units and integrated plant operation, assess membrane replacement alternatives, develop re-rating options and coordinate with the Texas Commission on Environmental Quality.
- Testing protocols are due by May 29, 2027, followed by a draft technical memorandum in November 2027 and a final memorandum in January 2028.
- SJRA expects Phase 2 to begin in November 2026 and run for about 18 months; a subsequent phase is intended to design and implement the selected improvements and replace the membranes.
Full report
San Jacinto River Authority’s board has authorised a $1.304 million engineering and testing programme to establish how its 30mgd GRP Surface Water Treatment Plant can replace ageing microfiltration membranes while potentially increasing use of existing treatment capacity.
The board approved the professional services agreement with Plummer Associates for Phase 2 of the GRP Membrane Replacement and Optimization project. The agreement comprises $966,000 in lump-sum services and up to $338,000 in cost-plus work, funded from repair and replacement funds.
The plant’s microfiltration membranes were installed in 2015. Phase 1 of the programme, completed in September, found that the membranes have an estimated three to five years of useful life remaining under current operating conditions. It also produced a stress-testing protocol for the next phase.
Staff said the programme will move through treatment processes individually to identify hydraulic constraints and determine how much water can be pushed through the existing plant. The work will cover pretreatment, membrane filtration and granular activated carbon (GAC), followed by limited integrated testing of the full surface water treatment plant.
The scope includes bench-scale jar testing to optimise coagulant type and dose, coagulation pH and potential polymer use. It will then move to full-scale pretreatment testing, including assessment of treatment performance, inclined plate-settler loading, chemical dose, pH, alkalinity and corrosivity indicators.
Membrane work will include short-duration testing at design-capacity, N+2 and N+1 flux conditions, followed by long-duration testing of two representative racks at selected elevated fluxes. The long-duration exercise is intended to assess sustainable flux, fouling rate, transmembrane-pressure development, recovery and cleaning frequency. SJRA will separately contract AriaFiltra for programming changes required to support N+1 testing.
The GAC programme will examine individual contactor performance, carbon age and replacement history, total organic carbon removal, backwash performance, pumping capacity and options for higher-rate operation. Consultants will also develop a performance model to evaluate carbon utilisation and predict performance under higher flows, N+1 operation and reduced organic loading.
After unit-process testing, the team will conduct integrated plant testing under higher-production conditions selected from the earlier work. This is intended to demonstrate concurrent pretreatment, microfiltration and GAC operation and assess effects on pumping, backwash, recycle, residuals handling, chemical systems, storage, instrumentation and controls.
Plummer will then develop feasible re-rating alternatives, phased capacity options and Class 4 opinions of probable construction cost. The work will identify required changes to ancillary systems, including pumping, backwash and recycle, residuals handling, chemical feed, storage, electrical service and SCADA controls.
Regulatory coordination with the Texas Commission on Environmental Quality is built into the programme. The consultant will evaluate disinfection contact-time alternatives, as the existing study supports 30mgd at a minimum ground-storage-tank volume of 15%; higher production would require an updated demonstration of four-log virus inactivation.
Testing protocols are due by May 29, 2027. A draft technical memorandum is scheduled for November 15, 2027, with a final memorandum due January 3, 2028. Staff expect Phase 2 to begin in November and last approximately 18 months. Phase 3 is intended to design and implement selected improvements and undertake membrane replacement.
This summary was generated by AI based on the source document and may contain errors.
Source: Board of Directors, San Jacinto River Authority