The document compares the operation and maintenance of vacuum sewer systems to gravity sewer systems. While there is a myth that gravity systems require no maintenance, the truth is that an entire industry exists to clean and repair gravity systems. Vacuum systems require regular checks of collection chambers and vacuum stations, as well as annual service and controller replacements every 10 years. Gravity systems require cleaning accumulated waste, rehabilitation, and pumping station maintenance. Vacuum systems have less operational risk and no confined space entry hazards. Overall, the document argues that while all sewer systems require maintenance, vacuum systems likely have lower maintenance costs than gravity systems.

1. Operation and maintenance
Vacuum vs. gravity
BG, Sofia Nov 2016

2. Vacuum sewer systems
Operation and maintenance
Operation and maintenance | 11/22/2016 Page 2
The myth: no maintenance in gravity systems
The truth: a whole industry is built on cleaning and repairing gravity systems

3. Vacuum sewer systems
Operation and maintenance
The truth:
Operation and maintenance | 11/22/2016 Page 3

4. Vacuum sewer systems
Operation and maintenance
The myth: no maintenance
in gravity systems
So, let us speak about it!
Operation and maintenance | 11/22/2016 Page 4
The truth:

5. Vacuum sewer systems
Operation and maintenance
Roediger® vacuum systems
Labour
▪ Regular check of collection chambers
▪ Regular check of vacuum station
Replacement/repair
▪ Annual service of the vacuum station
▪ Controllers (app. every 10 years) replacement
▪ Valve membrane (app. every 5 years) replacement
Gravity systems
Labour
▪ Regular check of manholes
▪ Pipeline inspection, CCTV inspections
▪ Cleaning accumulated sludge, slime and debris
(jetting with high-pressure)
▪ Flushing
Replacement/repair
▪ Service of all discharging pumps from pump- and
lifting stations
▪ Rehabilitation of gravity sewers
▪ Rehabilitation of manholes
Operation and maintenance | 11/22/2016 Page 5

6. Vacuum sewer systems
Operation and maintenance
Roediger® vacuum systems
Electricity consumption
▪ Vacuum pumps (approx.15-25 kWh/PE/year)
▪ Discharging pumps (2 pieces)
Network maintenance:
▪ No maintenance, vacuum network is self-cleansing
Sewage treatment:
▪ Handle only wastewater
▪ Handle aerated waste water
▪ Closed system - handle only communal wastewater
Gravity systems
Electricity consumption
▪ Discharging pumps of all lift- and pump stations
Cleaning the system:
▪ H2S deodorization
▪ Cleaning of sedimentation
▪ Flushing, spooling the system
Water treatment:
▪ Handle big amount of infiltrated ground water
▪ Handle aged and possibly septic wastewater
▪ Handle wastewater from unsure source
Operation and maintenance | 11/22/2016 Page 6

7. Vacuum sewer systems
Operation safety
Roediger® vacuum systems
Safety operation!
Gravity systems
Operation and maintenance | 11/22/2016 Page 7

8. Vacuum sewer systems
Operation safety
Roediger® vacuum systems
Operation safety
▪ No operational risks to operators
▪ All equipment can be accessed from the ground
level
▪ No direct contact with wastewater
▪ No climbing into manholes or confined spaces
required
Gravity systems
Atmospheric hazards in confined spaces:
▪ Low oxygen (two men required)
▪ Hydrogen sulphide (corrosion)
▪ Explosive concentrations of methane
Physical hazards with confined space entry
▪ Objects falling onto operators
Biological hazards:
▪ Germs and diseases
▪ Viruses
▪ Pathogenic organisms
Insects, animals
Bad smell
Operation and maintenance | 11/22/2016 Page 8

9. Vacuum sewer systems
Operation costs
Operation and maintenance | 11/22/2016 Page 9

10. Vacuum sewer systems
Maintenance costs
Operation and maintenance | 11/22/2016 Page 10

11. Vacuum sewer systems
Operation costs
Operation and maintenance | 11/22/2016 Page 11

12. Vacuum sewer systems
Maintenance costs
Operation and maintenance | 11/22/2016 Page 12

13. Vacuum sewer systems
Operation and maintenance
Wishful thinking: System with no maintenance
Reality: Every system needs maintenance
Operation and maintenance | 11/22/2016 Page 13

14. Aqseptence Group GmbH
Vacuum Sewerage & Recovery Systems
Kinzigheimer Weg 104-106
63450 Hanau / Germany
Telephone +49 (6181) 309-0
roediger.water@aqseptence.com
www.aqseptence.com