Why Does The Wastewater Flow Increase in Water Purifiers?

In the precisely operated world of reverse osmosis systems, every drop of water tells a story. When the wastewater flow suddenly increases, it may signal hidden issues in the system. As a professional brand deeply engaged in the water purification industry, UMEK has already uncovered the reasons behind this phenomenon.

When wastewater flow increases, it directly reflects a higher wastewater ratio in the RO system. The wastewater ratio is a core parameter set to balance production efficiency and membrane lifespan. It ensures that the salt and contaminant concentrations in the concentrate remain within a reasonable range. Defined as the ratio of wastewater flow to pure water flow, a higher wastewater ratio means greater wastewater discharge. 

Figure 1: Internal Water Flow Path of the Purifier

So, why does the wastewater ratio increase? Let’s break it down step by step.

1. Insufficient feed water pressure.
The main causes of insufficient feed water pressure are clogged filters or a fouled RO membrane. When filters clog, the resistance to water flow increases. With the feed water supply pressure relatively stable, the actual pressure in the system drops after overcoming this resistance, resulting in insufficient feed water pressure. If the RO membrane is clogged, higher pressure is required to push water through it. Since the booster pump provides constant pressure, it may not be enough to force all water molecules through the membrane. This reduces pure water output, increases wastewater flow, and raises the wastewater ratio. In this case, you can use the automatic flushing function to clean the filters or RO membrane. If the effect is minimal, timely replacement is recommended.

2. Malfunctioning wastewater solenoid valve or inlet solenoid valve.
The wastewater solenoid valve is usually installed at the wastewater outlet. After water passes through the RO membrane, the concentrate is discharged through this valve. If the valve fails to close or does not seal properly, wastewater discharge will increase. If the inlet solenoid valve fails, the system may continue discharging wastewater even when not producing water. In this situation, the pure water output drops to zero and the wastewater ratio approaches infinity. Timely repair or replacement of the faulty valve is necessary.

3. Low ambient temperature.
The optimal operating temperature for RO membranes is 5℃–25℃. At low temperatures, the membrane pores contract due to thermal contraction, reducing the volume of water passing through and increasing wastewater flow. This is not a cause for concern—once the temperature rises, the purifier will return to normal purification efficiency.

Additionally, for water purifiers equipped with a pressure tank, if the check valve ages or fails, water stored in the pressure tank may flow back into the wastewater line. This also causes pressure loss in the high-pressure pipeline and frequent restarts of the pump. In this case, stop using the purifier and replace the check valve promptly.

In conclusion, when wastewater flow suddenly increases, there’s no need to panic. UMEK not only provides you with high-quality water purification equipment but also offers a comprehensive supply chain system and fast-response after-sales support. This ensures that you always enjoy healthy, safe, and pure drinking water, while easily handling any small issues during use.

Contact Information:
Tel: +86 19331305749
Email: sales@cnumek.com / sales@amandawatertech.com
Website: www.amandawatertech.com / www.cnumek.com