Common challenges in desalination plant maintenance and practical solutions

Introduction to Desalination Plant Maintenance Challenges

Is your plant’s desalination plant experiencing frequent shutdowns, reduced efficiency, or increased maintenance costs? These problems are often rooted in challenges specific to the plant environment — not just water quality.

In power plants, desalination plants operate under high operating pressures, fluctuating production loads, and unique safety constraints. This article examines six key challenges and practical solutions for effective desalination plant maintenance in these sensitive environments.

Why is desalination plant maintenance different in power plants?

In thermal power plants (gas, steam or combined), desalination plants are not a stand-alone unit, but a vital part of the water and steam cycle. Any disruption in them directly affects power generation.

Three unique characteristics of power plants that complicate desalination plant maintenance:

1. Strong dependence on the stability of the supply of clean water to the boiler

2. Strict time constraints on maintenance shutdowns

3. Harsh environmental conditions: high temperatures, vibrations, and air pollution from combustion processes

Therefore, maintenance solutions must be not only technical, but also in line with power generation schedules.

Challenge 1: Poor feedwater quality due to variable source

In many coastal power plants, seawater is used as the feedwater for desalination plants. But:

• Seawater quality varies with the season (e.g., turbidity during rainfall or fine dust)
• Maritime activities (dredging, shipping) can increase the concentration of suspended solids
• Old pretreatment systems may not cope with these fluctuations

Consequences:

• Fouling of membranes in RO systems
• Formation of complex deposits (a combination of carbonate, sulfate, and silica) in thermal systems

Practical solutions:

• Continuous monitoring of TSS and SDI (suspended solids index and fouling index)
• Use of customized flocculants adapted to seasonal conditions
• Installation of multi-stage pretreatment filters with automatic replacement

Challenge 2: Time constraints on maintenance outages

In a power plant, every hour of downtime = lost revenue. Therefore:

• Long-term downtime (e.g. 10 days for a complete washout) is not possible
• Maintenance teams must operate in short windows (24–72 hours)

Consequences:

• Incomplete cleaning
• Residual deposits that quickly regrow
• Hastily made and sometimes wrong decisions

Practical solutions:

• Perform advanced chemical washes with tight schedules (2–4 days)
• Use fast-acting formulations with efficient corrosion inhibitors
• Coordinate with power generation schedules to plan short outages

Note: Smart chemical washes can be completed in 72 hours — if planned and simulated in advance.

Challenge 3: Formation of resistant scale in thermal systems (MED/MSF)

In large power plants, thermal desalinizers (MED or MSF) are more common. But:

• High temperatures (up to 120°C in MSF) → Formation of hard, insoluble calcium sulfate layers
• Presence of silica in the feed water → Formation of glassy deposits that are not easily washed

Consequences:

• Severe reduction in heat transfer
• Increase in pressure in the effects
• Risk of subsoil corrosion in titanium or stainless steel pipes

Practical solutions:

• Regular sediment analysis with XRD and XRF for precise composition identification
• Use of combined acidic detergents (combination of organic acids and chelating agents)
• Careful control of pH and temperature during washing to prevent damage to metals

Heat transfer pipes of the third refinery desalination plant before chemical washing

Heat transfer pipes of the third refinery desalination plant after chemical washing

Challenge 4: Biofilm and Microbiological Growth in RO Systems

In power plants using RO, the ambient heat and high humidity create an ideal environment for bacterial growth.

Consequences:

• Membrane fouling with biofilm
• Reduced water permeability
• Increased injection pressure
• Membrane degradation due to microbial metabolic acids

Practical solutions:

• Combined use of oxidizing (e.g. chlorine) and non-oxidizing biocides
• Perform membrane washing with biofilm-specific detergents
• Monitoring ATP (microbial cellular energy) to assess microbial activity in real time

Three warning indicators of biofouling:

1. Increase in differential pressure ΔP of more than 15%

2. Decrease in pure water flow

3. Decrease in system recovery (Recovery Ratio)

Challenge 5: Coordination between different units of the power plant

The desalination plant is affected by other units:

• If the cooling tower corrodes, iron will leach into the feedwater
• If the boiler leaks, boiler chemicals (e.g. hydrazine) may return to the desalination circuit

Solutions Practical:

• Establish an integrated monitoring system for water quality at all points
• Collaboration between operational teams (water, steam, treatment)
• Periodic inspection of potential leakage points between separate circuits

Challenge 6: Lack of technical expertise in local teams

Many power plants are located in remote areas and access to water chemistry experts is limited. This leads to:

• Use of traditional and suboptimal methods
• Reliance on general contractors without desalination expertise
• Decision-making based on guesswork

Practical solutions:

• Use of online or remote support services
• Train local teams on standard protocols
• Use of rapid analysis kits on site for immediate decision-making

❓❓❓ FAQ ❓❓❓

❓ Can the same maintenance program be used for all power plants?

No. Each power plant requires a customized program based on its geographical location, type of generation (gas/steam), and water source.

❓ Can anti-scalers replace periodic flushing?

No — they only slow down the rate of scale formation. Periodic flushing is still essential.

❓ Why is chemical flushing more critical in power plants than in other industries?

Because a mistake can lead to a national shutdown of power generation. Therefore, each formulation must be rigorously tested for safety and compatibility.

❓ Can RO and MED desalination plants be maintained simultaneously?

Yes — and it is recommended. Since they often use the same feed water source, coordinated maintenance is best.

✍️ Conclusion: Desalination plant maintenance is a systems strategy

Successful desalination plant maintenance does not depend on just “occasional flushing.” Rather, it requires:

• A deep understanding of its interaction with other plant units
• Data-driven monitoring, not guesswork
• Preventive planning aligned with the power generation cycle
• Decision-making based on scientific analysis, not general guidelines

The first step to improvement: Collect the last 6 months of operational data and compare it to baseline conditions. The second step: Collect a sediment or biofilm sample and analyze it in the laboratory. These two small tasks can save years of equipment life.

If you need expert advice to identify the type of sediment or the optimal selection of chemicals, Abrizan Company’s specialists, with more than 20 years of experience in advanced laboratories, are ready to provide customized solutions to various industries.

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