Water Services National Training Group and National Federation of Group Water Schemes

1
Water Services National Training Group and
National Federation of Group Water Schemes

• 7th Annual Rural Water Services Conference
• 18th September 2008

2
Septic Tank Effluent Drainage System STEDS
(Update) Jim McGuire Senior Engineer North
Tipperary County Council
3

• Background
• Project description
• Current status
• Experience /Identified Issues

4
Alternative wastewater treatment systems for
small rural communities

• The Challenge
• Sustainability
• Ease of Maintenance
• Robust performance
• Process performance
• Low energy costs
• Low operating costs

5
Approach

• Literature search
• Short list of options
• Real life applications
• Pilot Project

6
PROJECT TEAM

• Treatment System Orenco, USA
• Consulting Engineers Nicholas ODwyer Partners
• Contractor EPS, Mallow, Co. Cork
• Client North Tiperary County Council
• Water Services National Training Group
• Funding providing by Department of Environment
  ,
• Heritage and Local Government

7
STEDS Components

• Fibreglass Tank in each Garden
• 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

8
(No Transcript)
9
Components, cont.

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

10
60mm Ø main
43mm Ø service
11
(No Transcript)
12
Collection System

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

13
Secondary Treatment

• Packed bed filter
• Engineered textile material
• Complete, premanufactured package
• Operates in an unsaturated condition (not
  submerged)
• Uses filtration and biological/chemical reduction

14
Advantex Unit
15
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

16
Advantages

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

17
Benefits

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

18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Experience

• 1. Retrofit Challenge
• No rain water can enter system
• No ground water can enter system

22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
Experience

• 2. Sampling Challenge
• Low flows pose particular challenges
• Various arrangements tried

26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
Householders Play an Important Role
31
Experience

• 3. Householders Role
• No bleaches
• No discharges from water softeners
• No under sink macerators
• Minimise phosphates in detergents

32
COSTS

• 29 Houses served
• Cost outturn not finalised (850,000 excl. VAT)
• Includes range of non typical items

33
Non typical costs

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

34
Alternative wastewater treatment systems for
small rural communities

• The Challenge
• Sustainability
• Ease of Maintenance
• Robust performance
• Process performance
• Low energy costs
• Low operating costs

35
Conclusions

• Retrofit/rainwater challenges overcome
• Sampling challenges resolved
• Operating procedures improved
• Final judgement awaited
• Further Close monitoring
• Performance is positive
• Phosphates

36

• End

37
Water Services National Training Group and
National Federation of Group Water Schemes

• 7th Annual Rural Water Services Conference
• 18th September 2008