Periwinkle Residences Limited
Estate water demand and treatment design
A coastal estate gets drinking water it can trust from a single borehole because the treatment design assumes the worst water the site can produce, not the best.
Situation
Periwinkle Residences is a five-block coastal estate of roughly 100 flats in Lagos, supplied by one borehole and no municipal connection.
Complication
Coastal boreholes shift between fresh and brackish water. A single-path treatment plant is correct on some days and wrong on others, and wrong is not acceptable for drinking water.
Resolution
ASE modelled the demand and engineered a dual-path treatment design on BWT hardware: media filtration and UV for the non-brackish case, reverse osmosis for the brackish case, with disinfection, monitoring and alarms aligned to WHO and NIS standards.
Demand model
Per-flat consumption, peak factors and storage sizing for the full five-block estate. Lagos estates live with morning and evening draw peaks, generator-dependent pumping windows and the occasional tanker top-up when a source falls short, so the model sizes plant and storage for how the estate actually draws water across a real day, not for a nameplate average. Storage buffers were dimensioned so treatment interruptions do not become supply interruptions.
Dual-path treatment engineering
Two engineered treatment paths on BWT hardware covering both source-water cases: media filtration and UV disinfection when the borehole runs fresh, reverse osmosis when salinity rises. On the Lagos coast, saline intrusion moves with season and abstraction, so the design monitors source quality and switches paths rather than hoping the water stays friendly. Disinfection, water-quality monitoring and alarm architecture are designed to WHO guidance and the NIS 554 limits, and alarms are wired so a failure announces itself instead of waiting to be discovered.
Delivery planning
Turnkey budgets and a commissioning roadmap, worked through in site meetings in Lagos with the estate’s own delivery realities on the table: import lead times for treatment hardware, port clearance, local contractor scope and the sequence in which blocks come onto the treated supply. The roadmap orders the work so the estate is never without water while the plant goes in.
- Around 90 percent of the Lagos population relies on wells, boreholes or water vendors rather than municipal supply. Internet Geography
- NIS 554:2015, the Nigerian drinking-water standard, sets maximum allowable limits that borehole water in parts of coastal Lagos has been recorded exceeding. NIS 554:2015
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A senior reviewer will confirm fit before any proposed next step, and share references where the engagement allows it.