Ceramic Tanks

Ceramic tanks serve as highly corrosion-resistant vessels for storing and processing aggressive chemicals in municipal water and wastewater treatment plants, particularly for chlorine dioxide generation, sodium hypochlorite storage, and acidic chemical handling. These tanks utilize dense ceramic linings or solid ceramic construction to withstand pH levels as low as 0.5 and chlorine concentrations exceeding 15% by weight, conditions that rapidly degrade steel, fiberglass, and even high-grade plastics. Typical installations range from 500 to 15,000 gallons for chemical storage applications. The primary limitation is significantly higher capital cost compared to conventional materials, often 3-5 times more expensive than equivalent HDPE or fiberglass tanks.

• Chemical Storage for Sodium Hypochlorite: Ceramic-lined steel tanks store 12.5% sodium hypochlorite solution in 5,000-15,000 gallon capacities
• Ferric Chloride Storage: Used in 3,000-8,000 gallon sizes for coagulant storage in plants treating 2-25 MGD
• Caustic Soda (50% NaOH) Storage: Applied in pH adjustment systems for 5-50 MGD plants using 8,000-12,000 gallon tanks
• Polymer Storage: Houses diluted polymer solutions (0.1-0.5%) in 1,000-3,000 gallon day tanks

Daily Operations: Operators monitor chemical levels via ultrasonic or guided wave radar systems, checking for consistent feed rates and proper mixing circulation. Visual inspection through sight glasses reveals any ceramic degradation or chemical precipitation. Tank heating systems require temperature monitoring to prevent thermal shock to ceramic lining.

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Maintenance: Annual internal inspections require confined space entry with full respiratory protection due to chemical vapors. Ceramic repairs need specialized contractors with high-temperature curing capabilities. Preventive maintenance focuses on expansion joint integrity and heating coil function. Typical service intervals: quarterly external inspection, annual internal assessment, 15-20 year lining replacement.

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Troubleshooting: Ceramic spalling appears as white powder in tank bottom, indicating lining failure from thermal cycling or chemical attack. Unusual chemical consumption rates suggest internal precipitation from compromised lining. Warning signs include discolored sight glass areas and metallic taste in stored chemicals. Properly maintained ceramic tanks achieve 20-25 year service life versus 8-12 years for unlined steel.

• Ceramic Lining System: 3-5mm thick acid-resistant ceramic tiles bonded to steel substrate using specialized adhesives
• Steel Shell Structure: Carbon steel construction typically 3/16" to 1/4" wall thickness for municipal sizes
• Inspection Ports and Manholes: 24-36" diameter access points with ceramic-lined flanges
• Venting and Overflow Systems: Ceramic-lined vent connections and overflow piping prevent corrosion at vapor contact points
• Foundation and Anchor Systems: Concrete ring foundations designed for ceramic tank thermal expansion characteristics, typically 6-8" wider than steel-only tanks

• Hydraulic Loading: 0.5-2.0 gpm/ft² surface area for clarification applications; 2-5 gpm/ft² for contact/mixing basins
• Detention Time: 2-6 hours for sedimentation basins; 15-45 minutes for flash mix chambers; 20-30 minutes for flocculation basins
• Operating Pressure: Atmospheric to 15 psig for most municipal applications. Pressure vessels rated to 150 psig for specialized applications
• Temperature Range: -20°F to 180°F operational range. Thermal shock resistance critical for applications with temperature cycling
• Chemical Resistance: pH range 1-14 with specific resistance to chlorine (up to 10 mg/L continuous), sulfuric acid, and caustic solutions
• Structural Loading: Dead load plus 125% live load capacity. Wind loading per ASCE 7. Seismic design per local codes
• Tank Geometry: Length-to-width ratios of 3:1 to 5:1 for rectangular clarifiers. Depth typically 8-16 feet

• What process loading rate can the ceramic tank handle? Municipal clarifiers require 0.8-1.5 gpm/ft² for reliable performance. Exceeding 2.0 gpm/ft² causes carryover and poor effluent quality
• Can the ceramic material withstand site-specific chemical conditions? Standard alumina ceramics handle pH 3-11 and chlorine up to 5 mg/L. Specialized formulations needed for extreme conditions
• What structural design loads apply? Seismic zones 3-4 require special anchoring and flexible connections. Standard designs assume Zone 1-2 conditions
• How will thermal cycling affect tank integrity? Daily temperature swings >40°F or process temperature variations >60°F require thermal expansion joints and specialized ceramic formulations

• Division 40 - Process Integration
• Section 40 05 00 - Common Work Results for Process Integration
• Primary specification location for ceramic process tanks in municipal treatment facilities
• Secondary references in Division 46 (Water and Wastewater Equipment) for specific process applications

• Material/Equipment Verification: Verify ceramic membrane pore size specifications (typically 0.1-0.4 microns), confirm chemical compatibility with plant cleaning protocols, review flux rate guarantees and fouling resistance data
• Installation Requirements: Require specialized lifting equipment for heavy ceramic modules, plan for precise tank level control systems, coordinate electrical requirements for backwash systems
• Field Challenges: 12-16 week lead times typical, fragile handling during installation, limited field repair options
• Coordination Issues: Early coordination with controls contractor for automated cleaning cycles

• Evoqua Water Technologies - MEMCOR ceramic membrane bioreactors for 0.1-50 MGD applications
• SUEZ Water Technologies - ZeeWeed ceramic MBR systems, proven in municipal installations
• Metawater - flat-sheet ceramic membrane systems for smaller municipal plants
• Kubota Membrane - submerged ceramic membrane units for 0.5-10 MGD facilities with strong North American municipal references

• Polymeric MBR systems - Lower capital cost, easier maintenance, preferred for <5 MGD plants
• Conventional activated sludge with tertiary filtration - 30-40% lower capital cost, simpler operations
• Moving bed biofilm reactors (MBBR) - More robust for variable loading, easier troubleshooting

Work closely with manufacturer field service during startup - ceramic systems require precise optimization of cleaning cycles and flux rates. Many plants achieve 20-30% energy savings by optimizing permeate flow patterns. Negotiate comprehensive spare parts packages upfront, as ceramic elements have limited repair options. Consider pilot testing for challenging influent conditions before full-scale commitment.