Longking supplies Ozone Generators System for Santillana Drinking Water Plant in Spain
Santillana Drinking Water Plant (Madrid, Spain): 90 kg/h Centralized Ozonation Upgrade with NLO Ozone Generator Systems, CFD-Optimized Contactors and Full SCADA Integration
Longking EnTech Europe (formerly Newland EnTech Europe) was awarded in 2021 the supply, installation and commissioning of a major upgrade of the ozonation system at the Santillana Drinking Water Plant, owned and operated by Canal de Isabel II.
Santillana is one of Spain’s flagship drinking water ozonation references, with decades of operational history. The 2021 upgrade was designed to modernize performance and implement a centralized ozone generator system capable of feeding both pre-ozonation and intermediate ozonation, while also considering future increases in plant flow rates.
At a glance
Owner / Operator: Canal de Isabel II
Location: Manzanares El Real (Madrid), near the Santillana reservoir
Upgrade objective: centralized generation supplying pre-ozonation + intermediate ozonation
Ozone generation capacity: 3 × 30 kg/h (total 90 kg/h)
Generator platform: NLO Series (utility-grade ozone generator systems)
Engineering highlight: CFD study and retrofit of contact chambers to improve transfer + effective retention time
Safety: high-capacity ozone destructors + relief valves + demisters + winter heating elements
Cooling: SRIC-type closed-circuit architecture (dual-loop concept)
Controls: automatic dosing, local HMI + PLC, full SCADA integration, remote monitoring (“SENTINEL”)
Why this upgrade matters
Santillana DWTP has continuously evolved since the reservoir and plant infrastructure were developed, adapting its treatment line to raw water changes and regulatory requirements. The plant has long been associated with ozone, and modern treatment upgrades also highlight polishing stages such as activated carbon and advanced treatment concepts.
The 2021 project objective was to replace legacy concepts and consolidate ozonation into a centralized, efficient and controllable system that can reliably serve multiple ozone injection points and future capacity expansion.
Centralized ozone generator system - 3 × 30 kg/h (NLO Series)
The new ozone generation plant was implemented using three NLO Series generation units, each capable of producing 30 kg/h at 10% ozone concentration.
The design focus was not only dosing capacity, but also operability and lifecycle performance. The generators incorporate modern frequency converter technology (IGBT-based), supporting stable operation and strong electrical efficiency. and a specific energy consumption below 7.5 kW per kg of ozone.
CFD-driven contactor optimization (where real performance is won)
A key differentiator of this reference is the engineering work on the contact chambers. The scope included adaptation to the existing site and a detailed CFD study of the contactors.
The CFD analysis indicated that parts of the existing pre-ozonation chambers did not provide sufficient transfer guarantees. Retrofit modifications were therefore implemented to:
optimize ozone transfer to water, and
improve effective retention time by increasing the baffle effect and reducing short-circuiting.
This is the type of work that separates “installed capacity” from “delivered performance”.
Off-gas management and safety — high-capacity ozone destruction
The final design incorporated additional ozone safety features such as:
high-capacity ozone destructors, and
relief valves at the contact chambers.
The destructors are equipped with PLC control and a touchscreen interface for close monitoring. The destruction installation is complemented with:
liquid collection tanks, and
demisters to prevent water droplets/condensate from entering the destruction system.
Because winter temperatures at the plant can be low, the ozone destruction systems include heating elements to reach operating temperature rapidly.
Thermal management — SRIC-type closed-circuit cooling architecture
Cooling of the ozone generation equipment was designed using SRIC-type closed systems with two circuits:
Closed generator loop
demineralized water + additives
dual recirculation pumps (duty/standby)
continuous monitoring of flow, pressure and temperature
data acquisition and control through the ozone PLC
Primary/open loop (heat rejection)
fed with filtered plant water
cools the closed loop through heat exchangers
water is returned to the process after heat exchange
This design supports durability and stable operation under continuous duty.
Automatic dosing, PLC/HMI, SCADA integration and remote monitoring (SENTINEL)
Ozone dosing is performed automatically through a system of valves and flow controls, enabling stable injection of the required ozone dose.
All key performance values are collected in the ozone control PLC and integrated into the Santillana DWTP main SCADA. The management software was developed specifically for this facility, aligned with the operator’s requirements. The plant control incorporates the SENTINEL remote access system, enabling remote monitoring of installation status (subject to the facility’s cybersecurity policies).
From flagship reference to product platform — NLO ozone generator systems
Projects like Santillana demonstrate that real ozonation performance depends on the complete ozone generator system, not only on installed capacity. Longking EnTech Europe’s NLO ozone generator range is designed for municipal and industrial applications where utilities require stable output, safe integration and automation-ready operation.
A utility-grade ozone generator system typically includes:
oxygen supply concept (LOX / PSA, project-dependent) and gas quality management,
generator(s) + power supply with stable turndown control,
thermal management (closed-circuit cooling architecture),
injection/contacting equipment matched to each process point (pre-ozonation / intermediate ozonation),
off-gas ozone destruction and demisting to protect equipment,
PLC/HMI and SCADA integration with alarms, trending and optional remote access.
If you are evaluating an ozonation upgrade for drinking water (or a combined ozone/UV/AOP approach), our team can support feasibility, integration, commissioning and lifecycle planning.
For more information about this reference project or NLO ozone generator systems for drinking water treatment, contact our team: