Licensing to high-performance companies outside of Germany welcome.
The Schluff System features its own sewage program. This enables domestic connections and pumpstations to be controlled and operated via Internet. Thus optimal operation reliability is guaranteed and costs for maintenance are minimized.
The collecting of sewage by vacuuming was done in 1873 for the first time in Amsterdam but it was limited to the suction of sewage from deeper located places.
1959 Swedish Joel Liljendahl re-developed the vacuum sewerage. His aim was to save water for the toilet flushing and at the same time canalize weekend areas with low effort (narrow trenches). The trials seemed to be successful. The concern Electrolux developed a special membrane valve for suctioning water of the domestic connections. In Britain the piston angled valve was developed by Cowell and in the Netherlands the inner tube valve by E-VAC.
In the beginning of the Seventies the company Electrolux built the first vacuum plant in Germany, in Donaumoos in Bavaria. But soon after putting into operation the system proved to be very susceptible to faults and became discredited by several breakdowns. Insufficient knowledge in Physics leads to faults in the construction of the valves, the domestic shafts and the pump stations. The vacuum plants were partly shut down and replaced by conventional systems. The need of sewerage systems for the exploration of the rural area was priority and the problem had not been solved until then.
Due to the experience in the sewage economy the Federal Minister for Research and Technology ordered the development of a sewerage system at Engineering Office Schluff which was supposed to save costs in the rural area. The requirements were very stringent. In 6 years of research work and evaluation from the operation of 14 vacuum sewerage plants the new vacuum sewerage plant developed, which has been considerably improved in all parts compared to the recent type and was thus made operationally safe.
Main items were as follows :
The new valve was tested in function and wear and tear with 400,000 switching procedures. After that it showed signs of abrasion of sand but it was still vacuum proof. What does that mean? The sewage transport for a single family home with 4 persons needs 10 openings per day, corresponding to 3,000 per year and approx. 300,000 opening procedures in 100 years. These assumptions were proven from the operation experience. Not one single valve was destroyed or replaced in approx. 25 years.
The suction of the valves was also considerably improved. The former pneumatically controlled valves only amounted to 5.8 kg due to the constricted passage. For the new developed valves the suction could be improved to approx. 20 kg due to the free passage. The conveying capacity of the pneumatically controlled valves amounts at 0.6 bar negative pressure approx. 2.5 to 3 l/sec. The new developed valve reaches a conveyance capacity of 8 to 8.5 l/sec.
The reconstruction of the valve leads to no more blockages. The life duration was practically proven by a valve, which has been in the position to convey sewage of 5000 daily visitors and 3 taverns without any problems for 23 years.
Another important meaning also had the increasing of the valve‘s closing force. This amounts to 260 kg for the new developed valves. The former pneumatically controlled valves amounted to only 3 and 5 kg according to negative pressure.
The installation method of the pipe network as well as the involvement of outgoing domestic connections and pipes were improved and proven by research.
The pump stations of different types available on the market are working more or less properly. For short distances (5-6 km) feed pumps have proven to be successful in the pressure tanks in wet well installation because they can discharge sediments and thus hardly lead to blockages at the same time.
For larger distances (20 km without intermediate pump works) the development of vacuum pneumatic pump stations was of considerable meaning, as the sewage was collected in vacuum tanks and after that further delivered by pressure air.
Every community disposes of
For a safe and economic operation these differences have to be even. This is ideally done in the newly invented vacuum sewerage by computer control. At the same time the plant is surveyed via Internet. Thus costs for staff are saved and provides safety for the operator.
© 2000-2016 Dr.-Ing. Reinhold Schluff