Reverse Osmosis (RO) is one of the most important ways of purifying water and making it safe for drinking. This purification method has been practiced for many years now. Initially it was intended for industrial purpose, but after seeing the effectiveness of the system in purifying water, it was then adopted for commercial and residential use. RO system have wide application from clean drinking water to dialysis healthcare applications. RO is a membrane-based demineralization technique used to separate dissolved solids from solution. It is the process by which an applied pressure, greater than osmotic pressure, is exerted on compartment that once contained high-concentration solution. This pressure forces water to pass through the membrane in the direction reverse to that of osmosis which help for the water purification.
Typical components of RO System:
- Raw Water Pump : To generate the pressure for down the line system
- Multi Grade Pressure Sand Media Filter: The water is first filtered by pressure sand filter unit for removal of suspended matters and turbidity.
- Activated Carbon Media Filter: To remove colour, odour, chlorine, oil & grease from the raw water.
- Micron Cartridge Filter (MCF): These are pressure vessels fitted internally with spun or pleated cartridge element, which removes micron sized particles.
- Antiscalant Design System: To prevent membrane from scaling (hardness).
- High Pressure Pump: A high-pressure pump is provided for supplying the feed water to RO System at high pressure.
- RO Membrane: Semipermeable membrane to remove ions, molecules, and larger particles from drinking water. It consist of polyester base, polysulphone layer and Polyamide layer and all these layers are rolled together in the form of a tube.
Classification of RO System:
Small capacity – Generally having a capacity of less than 100 liters per hour (LPH) and compact, used in household purposes.
Medium capacity – Generally having a capacity range of 500 – 1000 LPH, used in household, apartments, offices, small factories, etc.
Large Capacity / Industrial RO Plants – Capacity having more than 1000 LPH. Applicable for bottling plants and water treatment for chemical industries.
Common Failures in RO System
In order to reduce the failures of RO plant, remote monitoring & predictive maintenance system shall be implemented using NEERO – An Internet of Water System which applies Internet of Things technology. NEERO enable real time remote monitoring and analytics by obtaining RO system data from various sensors and transducers for measuring TDS, pressure drop, temperatures, flow of water, water level, pH value etc. and connected with an IoT gateway. The data collected is communicated through GSM to cloud web/mobile application where the data are interpreted by using NEERO algorithms for the maintenance manager or RO system service team diagnosis to enable preventive and predictive maintenance of the RO system. NEERO can be directly installed with RO system through retrofitting or interfacing with the control panel of the RO system to retrieve data and further analytical insights and actions.EXPLORE NEERO
Benefits and Outcome Values of NEEROFor RO System User
- Enable predictive instead of scheduled maintenance
- Enable uninterrupted supply and ensure availability
- Automated RO system initiated service/maintenance request
- Smart & connected diagnostics on failure exception conditions
- Fewer emergency repairs visits
For RO System Manufacturer / Dealer / System Integrator / Service Provider
- Efficient field service management
- Enable predictive service management
- Proactive service man power allocation for upcoming services
- Proactive spare parts / consumables arrangement for upcoming services
- Enable optimum spare parts / consumables inventory management
- Enable predictive instead of scheduled services
- Ability to identify RO system design and installation process issues
- Superior product design based on improved understanding of usage behavior
- Enable new revenue streams like water as a service
| Failure | Effect |
| Antiscalant | Scale formation on membranes, usually in the back-end stages – high salt passage, Pressure difference in final stage. |
| Ineffective sanitization procedures | Bio-fouled pipe-work, cartridge filters and membranes – high Pressure difference. |
| High iron content | Iron loading on cartridge filters. Iron fouling of membranes – high Pressure difference, low permeate flow. |
| High organic content | Humic substances and organic fouling on membrane – low permeate flow, high feed Pressure |
| Colloidal breakthrough | Colloidal particles foul micron filters and membranes – high Pressure difference, low permeate flow. |
| Granular activated carbon filters | Carbon fines foul micro filters and membranes. |
| Overdosing of coagulant | Cationic coagulant fouls membrane – low permeate flow, high feed Pressure. |
| Overdosing of chlorine | Membrane damage – high salt passage and increased flux. |
| Permeate tube “O” ring failure | High salt passage. |
| Ineffective biocide | High bacterial / fungal counts in water samples. Biofouling of membranes – high Pressure difference. |
| Sand / Multi-media filter breakthrough | Colloidal and bacterial fouling of micron filters and membranes. |
| Acid dosing | Scale formation – CaCO3 only. |
| Poor performance on start up after shutdown | Fouling / scaling of membranes. |
