Water Services National Training Group

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Water Services National Training Group

• 11th Annual Conference
• 6th September 2007

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Septic Tank Effluent Drainage
System STEDS Matt Shortt Director of
Services North Tipperary County Council
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• Background
• Project description
• Current status
• Preliminary results

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Alternative wastewater treatment systems for
small rural communities

• Requirements
• Sustainability
• Maintenance
• Risk of failure
• Process performance
• Low energy costs
• Low operating costs
• Renewable energy options

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Approach

• Literature search
• Short list of options
• Real life applications
• Evaluate whole life costs

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• Alternative collection systems
• Alternative treatment systems

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STEDS vs Gravity Sewer
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Septic Tank Effluent Drainage System (STEDS)

• Septic Tank Effluent Pumping
• Septic Tank Effluent Gravity

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STEDS Components

• Fibreglass Reinforced Tank
• Primary treatment in interceptor tanks
• 1000- or 1500-gallon tank per residence
• 70 removal of fats, oils, and greases
• 24-hour emergency storage
• 12-year pumpout with 95 confidence
• Abuses stay in interceptor tank
• Chemical sources easier to identify

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Components, cont.

• Pump vault
• High-head effluent pump
• Filter cartridge
• Float assembly
• Discharge assembly

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Collection System

• Shallow burial depth
• Laid to contour of land
• No minimum velocities
• No oversized designs
• Low operation and maintenance costs

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Secondary Treatment

• Packed bed filter
• Engineered textile material
• Appropriate tankage and timed dosing
• Complete, premanufactured package
• Highly stable, reliable
• Operates in an unsaturated condition (not
  submerged)
• Employs intermittent dosing
• Uses filtration and biological/chemical reduction

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Advantages

• Flexible in design
• Adaptable to varying site conditions
• Allows for phased development, modular
• Can be integrated into existing sewer
  infrastructure
• Can be integrated into existing treatment system
• Design includes storage/reserve in the event of
  power outages or need to repair mainline break
• Low-impact construction
• Minimal disruption to community

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Advantages

• Cost-effectiveness
• Low initial costs
• No manholes
• No pumping stations
• Low operating costs
• Low maintenance costs
• Low and gradual repair/replacement costs

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Benefits

• Allows the construction of houses in areas where
  standard sewers or septic systems cannot be used
• Has affordable installation costs and low
  maintenance costs
• Has little visual impact

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Householders Play an Important Role
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• Current Status
• Performance
• Costs

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60mm Ø main
43mm Ø service
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Advantex Unit
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Non typical costs

• Shipping
• Retrofit project
• Reconfiguration of existing connections
• Ground conditions
• Telemetry/data capture
• Sampling/monitoring
• Additional connections
• Additional single unit treatment system

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• End

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