An Offshore proposal for Sewage Treatment in Victoria

Main considerations:

“ If nothing has been done so far, anything we do to improve will be better than this now” .

• The presented purpose is an technique alternative to prevent the disorder from the

installation of a sewage treatment plant related with the construction services and environmental impact in the onshore nearby .

• This proposal despite bold look and to be a paradigm change for sewage treatment environment , presents no technological challenge as it is based on classic sewage treatment processes converted in submarine environment whose technology for construction and subsea installation is now fully dominated by Petroleum offshore industry.

• The presentation describes the basic concepts to be applied to the development of the project, to be developed on the basis of information not provided yet.

• The results to be obtained for the specifications of the effluents to be discharged into the ocean, can follow a schedule of progress according to the project evolution curve.

• We consider in order, the following factors are most striking in the deployment cost of this offshore project when compared to onshore:

1- Depth determined for the subsea facilities. 2 - Meteorological window for service at sea.

Sewage flowrate: Figures obtained from the CRD indicate 66,000 cubic meters or 66 Mega Liters from Mac Caulay and 40,000 cubic meters or 40 Mega Liters from the Clover point are discharged through the deep sea outfalls daily. This totals 106 Million liters/ day or 4416m³/hr .

Contaminants ( From newspaper) : Between tests in 2010 and 2013, the average fecal coliform count in Victoria's wastewater pipes went from 5.3 and 5.7 million bacteria per 100 millilitres of water up to 7.2 and 9.3 million bacteria per 100 millilitres of water. For reference: B.C. guidelines peg safe levels at 200 fecal coliforms per 100 millilitres for recreational beaches, and 14 fecal coliforms per 100 millilitres for shellfish harvesting.

From the report of “ Responsible Sewage Treatment Victoria” RSTV.

Preliminary Data:

Classic Sewage Treatment Process

The new proposal for the sewage outfalls is to simply adapt the subsea offshore technology currently in use in the offshore oil industry.

The New Concept

Environmental safety is crucial for the offshore oil industry and necessarily to be certified by current international regulations. Assurance of high quality standards is achieved by having the entire project, construction and installation by a third party certification body. All subsea operation can be monitored from onshore. The cost for the installation, operation and maintenance in shallow offshore waters is not very high, relative to the cost of a new onshore sewage treatment station, underground pipe installation and mainly when we also take environment impact in consideration, like in Victoria.

All the construction and subsea installation technology are fully developed and all ready in application in many offshore facilities.

Exemple of offshore system in operation from others.

STATOIL

Sewage treatment stage to be done underwater

Submarine manifold system for aeration

Pumping Room

Submarine Manifolds for air injetction using high technologic ventury can be installed in specific quantities all long the offshore discharge system.

Air inlet

Air in let Buoy system

Sea level

1MW Ozone Generator.

sewage water

To the open sea

Treated water

Sewage Water

Esquimalt and Clover Point Areas

Ozone injection

The schematic System for the Outfalls Upgrade

Additional Secondary Treatment System

After appropriate studies are completed and appropriate level of contaminants removal is established, if necessary, complementary barges can be sunk into the sea to work in the sewage treatment tanks. These barges/tanks will work with a ballast system to rise and sink in accordance with the needs for maintenance and system operation. Specific pipeline can send the treated “solids” and/ “ mud” to be treated on shore

Exemple of the submarine sewage station in operation. Accordingly with the project, only one tower will be visable at the sea level .

CRD

Possible cicles to improve aeration and/or Secondary Treatment

Cicle 1 (Manifold system)

Cicle 2 (Sunk barge tanks)

Main flow of the sewage outfall

Desinfectant gases or Chemicals Injection

Phase of Seawage Treatment where the Sunk barges may be Applied.

Submerged Barge with tanks for Denitrification and Nitrification treatment to be installed in specific quantities all long the offshore discharge system.

Air inlet

Air in let Buoy system

Sea level

Submerged barges Tanks To the Secondary Treatment improvement.

To open sea

Treated water

Sewage Water

Sea botton

Tank Barge for aeration

From stage 1

Pumping Room UV Room

Alternative 2

Venturi system Main Water Flow by pump

Secondary Flow

Surface Air injection with Venturi System

Underwater manifold

Alternative engineering studies to drill the outfalls pipeline Special gasket and reinforciment device for hot tape of existing outfalls pipeline

To be developed accordingly to the actual outfalls pipeline piping structure

For the flow rate of 4400m³/hr we consider 6 pumps as described bellow.

Barge Main Deck with Submarine manifold module

BSWMS ( Ballast and Sewage Water Management System) Similar process is applied to the modern Ballast system.

Suspension and solid clean up process

Hi SEA technology

Similar visual aspects for the UV room. Los Angeles Utraviolet disifection Facility

Complementary disinfection alternatives

UV treatment unit

New Tecnology for Ozone Aplication

Submarine Sewage Master Basic Plan Months

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Ativities Sea bed topograph and research

FEED development

Documentation for BID

Licenses

BID and contract signature

Barge procurement

EPC for Barge

EPC for Modules

Main deck Integration

Barge transport for location and installation

New outfalls EPC

Submarine barge and pipeline integration services

Comissioning and pre-operation

END