TROUBLED WATER
A CLEAR SOLUTION
TREATMENT TECHNOLOGY EXPLAINED
TROUBLED WATER; A WORLDWIDE PROBLEM
More than half of the world’s population lives within a 100 km or 60 miles distance from the coast. This is more than 2.7 billion people. Rapid urbanization will lead to more coastal megacities containing 10 million or more people. By the end of the millennium 13 out of 15 of the world’s
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largest cities will be located on or near the coast. Growing population in coastal areas leads to more marine pollution and distribution of coastal habitats. Some 6,5 million tons (6,500,000,000 kilo) of litter finds its way into the sea each year. The Baja California in Mexico is polluted, so is the Gulf of Izmir in Turkey. On the paradise island of Raratonga of the Cook Islands, untreated waste water is dumped into the laguna. Even the sewage of Brussels, the capitol city of the European Union flows unsufficiently treated into the Schelde river on its way to the Northsea. In the UK, daily approximately 290 million gallons of raw or inadequately treated sewage is pumped into the sea (Hines, 1997)
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Sewage represents a severe threat to the marine environment and to human health; it can make beaches potentially hazardous to all forms of life. It often contains harmful chemicals, contiminants, disease-causing bacteria and viruses, and dissolved material and solid matter.
In most coastal areas, there are cities and towns where every available square meter of land area is used.
Often they started out as settlement many years ago when there was sufficient surrounding land and an understanding of environmental concerns did not exist. The first sewer systems in such settlements were built at the turn of this century and in most cases emptied directly into an adjacent bay. Even now, often the untreated fluids and solids flow into the coastal waters. Over the years, all the available land has been taken for housing, commercial purposes, or infrastructure. Environmental concerns do exist now. Coastal populations continue to grow. So do sanitary concerns. The question is not what to do with the wastewater. The answer is clear: treatment. The question has become where and how?
| Most of the built-up areas surrounding the Mediterranean Sea are situated in very specific conditions where the coastal patterns and historical urbanization limit the available space for land based sewage treating facilities. If a city council decides to take proper care of the sewage by building a waste water treatment plant, it must take in consideration the current state of its existing sewage system.
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Such systems are usually based on normal gravity float and the sewage discharges directly into the adjacent bay.
Since it is unlikely to find adequate building sites on the tourist promenade, costly diversions of sewerage systems are essential to bring the waste where it belongs, out of the site, back up the hill or where ever the possibility to construct a sewage treatment plant would be. Such diversions could in complicated historical estate complex cost more then sewage treatment plant itself. That brings us to another problem: costs. It is not a typical problem tourist or archeological locations. Money, or lack thereof, is a fundamental problem with treating sewage. In introducing new and more effective methods sewage treatment companies are finding funding for land-based treatment facilities not sufficient to cover expenses.
Honiara, the capitol city of the Solomon Islands
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This message was posted on the ..xx.. forum on April 16, 1999 at 02:46:46:
The disposal of sewage to ocean by both the ..xx.. and the Solomon Islands' .. xx.. is a major
concern. Untreated sewer continues to be disposed off the coast of Honiara endangering marine life.
There is no strategic plan for a sewerage system for Honiara and ..xx.. continues to allow newly
residential buildings for the use of septic tanks.
For years to come this is going to be a major concern to our environment and underground water
resources. I believe that ..xx.. in association with revelant authorities, people should put their head together in
considering building either mechanical waste water treatment plant for Honiara township or consider a
pondage type treatment to treat both biosolids and neutralising phosphate and nitrate concentration that
is currently disposed into the ocean.
A concerned citizen
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There is a system that solves a problem of coastal wastewater pollution. It can process municipal sewage from medium to large cities situated in coastal areas where local topography often limits the available sites for land based treatment facilities. In the Czech Republic a floating waste water treatment plant was developed as a cost effective solution for processing municipal sewage from medium to large cities situated in coastal areas where local topography often limits the available sites for land based treatment facilities. It can be hooked to any existing canal system in a matter of days and starting to treat the sewage that otherwise is dumped in the costal waters. It offers the possibility to recycle up to 88% of the treated wastewater and return it to use in the community. In communities facing water shortages, this capability may be a key factor in decision making process.
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The new patented idea was born in the Czech Republic. It places the Waste Water Treatment Plant on a floating platform which may be anchored in a suitable distance from the city or village it serves. An underwater pipeline provides the connection between existing sewerage system and the floating plant.
click picture for an enlargement
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AN ENVIRONMENTAL IMPROVEMENT ONE CANNOT REFUSE.
Everyone is looking for an offer one cannot refuse. Environmental decisions are often dragged because of the additional cost they imply. The floating waste treatment plant promises to bring benefits all the way. For one, it is a very cost-effective solution. Appropriation of land for the waste treatment plant is unnecessary, freeing valuable space for other development. No expensive earth moving or reclamation is required. The disruption and delays of land-based construction projects are all but eliminated by the prefabrication of individual plant components assembled and shipped over water from the nearest shipyard. Duration of construction within the municipal area is minimized since the most complex elements of the plant are pre-fabricated at an industrial facility. The floating treatment plant eliminates much of the land based construction costs and is thus more economical. The only on-shore structure required is a simple pump house to move wastewater through the pipeline to the offshore platform.
The modular design of the floating plant also means that communities small and large can add the appropriate number of units for their size and even increase capacity as their population and tourism grows. The modules may be combined into complete systems comprising two to four units as needed to treat the required volume of waste.
AN EYESORE TURNED INTO A RECREATION FACILITY
Most wastewater treatment facilities would be an eyesore on otherwise beautiful coastline. One would assume that this eyesore is now being moved from the land to the see and the beautiful view of the sun set over the water is spoiled. The view may not be quite the same anymore, but it will not be spoiled. The visible section of the treatment plant can be disguised by a variety of purpose-built configurations. The technological components of the waste treatment process are hidden and sealed within the submerged section of the hull. One of the most attractive applications might be a yacht club facility providing recreational dock space or a harbor restaurant. The superstructure may include showers and bathrooms, storages, workshops for servicing, club-rooms and restaurants. A well-thought design concept can enhance the aesthetic attractiveness of the community it serves for both residents and tourists. If the floating plant was used for the relief in a industrial commercial area it could facilitate a heliport, a harbormaster's platform, or service area for shipping or fisheries.
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Seen from the shore, the floating waste water treatment plant doesn't have to be an eyesore. The superstructure can be designed in multi-purpose variation. The superstructure over the operating hall roof may be constructed as a lighttower or beacon. It could also be a coast card or harbor police station. This rendering suggests a marina (including a clubhouse or restaurant), with floating moles to moore yachts.
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The multipurpose configurations offer the opportunity to create a partially or fully self-financing model, since the concession granted to operate on-board the floating plant can be required to pay a rent that partially or completely offsets the acquisition cost. Thus the facility can also be self-financing.
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Small coastal communities have an inherent limitation of available land space. If they intend to provide such basic municipal services such as fresh water and a clean environment, until now they had no choice but to construct a land based treatment plant. To develop a suitable site in constrained and often geophysically challenging terrain entailed considerable expense that in some cases was totally uneconomical. Fortunately, these municipalities now have a viable alternative by making use of the vast unused surface area offered by the sea.
click picture for an enlargement
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The Floating Waste Water Treatment Plant would be anchored a suitable distance from the city or village it serveswithin a protected bay, or behind and existing or specially constructed breakwater. In a normal configuration, waste water effluent from the urban area is transported via a single or double pipeline to an underground storage system located adjacent to the on-shore pumping station. Connection between existing sewerage system and the platform is provided by an underwater pipeline. The transport pipeline can itself be installed as an underwater or floating system. Minimum water depth for the platform installation is 5 meters with local wave heights not exceeding 1 meter.
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FLOATING vs. LAND-BASED; SIGNIFICANT ADVANTAGES
Compared to the construction of a land-based treatment plant, a floating wastewater treatment plant eliminates many time and procedural problems, and offers significant advantages:
- Appropriation of land for the waste treatment plant is unnecessary, freeing valuable space for other development.
- Duration of construction within the municipal area is minimized since the most complex elements of the plant are pre-fabricated at an industrial facility.
- The floating treatment plant eliminates much of the land based construction costs and is thus more economical.
- Most wastewater treatment facilities would be an eyesore on otherwise beautiful coastline. The floating facility reduces the impact of providing a necessary municipal service and enhances the aesthetic attractiveness of the city it serves for both residents and tourists. In fact, the driving force in creating the floating wastewater treatment plant is to dramatically improve the environment of the community it serves. The technological components of the waste treatment process are hidden and sealed within the submerged section of the hull. The visible section of the treatment plant can be disguised by a variety of purpose-built configurations including a harbor restaurant, a heliport, a harbormaster's platform and many others. One of the most attractive applications might be to provide additional recreational dock space and services.
- The multipurpose configurations offer the opportunity to create a partially or fully self-financing model, since the concession granted to operate on-board the floating plant can be required to pay a rent that partially or completely offsets the acquisition cost.
- The Floating Treatment Plant is equipped with an ionizing element for the final stage of waste treatment. This additional capability offers the possibility to recycle up to 88% of the treated wastewater and return it to use in the community.
LEGEND OF THE FLOATING TREATMENT PLANT
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click the picture for an enlargement
PRINCIPAL DIMENSIONS
Length: L = 30.9 meters
Width: B = 30.9 meters
Displacement: D = 2260 metric tons
Draught: T = 2.75 meters
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01. Mechanical rough separation
02. Contactor tank
03. Denitrification tank
04. Nitrification tank
05. Settling-up tank
06. Sludge storage tank
07. Homogenisation tank
08. Mechanical sludge pressing
09. Blower room
10. Overflow well
11. Drum filter
12. Containers
13. Lifting equipment for mixers
14. Crane, 3.2 metric tons
15. Crane, 1.0 metric ton
16. Gensets
17. Main switchboard
18. Storage batteries
19. Workshop
20. Operator's cabin
21. Lower deck entrance
22. Drinking water reservoir
23. Diesel oil storage tank
24. Lubrication oil storage tank
25. Diesel oil operation tank
26. Lubrication oil operation tank
27. Expansion cooling tank
28. Drainage water and machine sludge tank
29. Waste oil storage tank
30. Diesel oil purification
31. Fecal sump
32. Chemical treatment
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1. Mechanical Stage
The first step applied in the process is the automated separation and removal of macroscopic suspended matter, including sand and grease. The equipment for this stage may be located on the open deck, or in an enclosed ventilated structure. In environments where extremely high levels of contamination are common, an optional auto-cleaning rotating hydrosilo with press can be included.
2. Biological Stage
In this stage biological processes are employed in the removal of organic matter, nitrogen and phosphorus. C-D-N (or R-C-D-N in extreme cases) type activation with pneumatic aeration is typically utilized. Aeration is accomplished using an automated blower system which monitors the current dissolved oxygen concentration and mechanically mixes „C" and „D" zones. The system also includes monitoring of redox potential and internal recirculation pumps.
3. Tertiary Stage
This stage performs automated drum filtration to produce high quality treated water.
4. Sludge Management
The sub-systems for sludge management provide complete treatment of the waste material including chemical processing and mechanical dewatering (located in a special ventilated operation room).
The treated waste water is used in the treatment process itself, with the remaining water discharged into the surrounding environment. Treated water quality achieves the highest standards.
Captured and separated residual waste product is deposited into transport containers. These waste products can be used in agricultural fertilizers or transported to dump sites for reclamation. Rakings are automatically packed into plastic foil for land fill storage, or, alternatively, can be incinerated. Removal of rakings and sludge from the the floting treatment plant is provided by a service vessel which could operate among several sites in a given region.
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These pipes should not be seen any more, any where.
Pollution from discharging raw sewage in oceans, seas, coastal waters, lagunas or rivers must be stopped. There were always landbased treatment solutions. In addition, there is now a floating solution for cases were landbased treatment was difficult or impossible.
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For information on the
Floating Treatment Plant, you may contact:
Ivan Vesely
Tel: +420 731 537 088
E-mail:
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