Assessment of Inactivation of IHNV in Fish Processing Wastewater with Dissolved Air Floatation and Ultraviolet Light Disinfection

Final Report

Marine Harvest Ltd.
AIMAP-2010-P09

Table of contents

1. Executive Summary
2. Project Description
Introduction
3. Methods and Deliverables
4. Status of Project and Future Activities
5. Conclusion

1. Executive Summary

The purpose of this project was to determine the effectiveness of infectious hematopoietic necross virus (IHNV) inactivation in fish processing wastewater through use of dissolved air floatation (DAF) and ultraviolet (UV) light disinfection treatment system as an alternative to chlorine disinfection.  The full scale system is installed at Marine Harvest Canada’s (MHC) Atlantic salmon processing plant in Port Hardy, BC. 

As a physical disinfectant, UV is less sensitive to variations in water quality than chlorine, does not produce harmful by products, is safer to operate, and has been adopted in numerous industries.   Despite its advantages, the fish processing industry has been reluctant to accept the UV technology without a full scale reference installation.   The project objectives are to provide the reference installation, determine the dosage rate required to achieve a four log-removal of the virus, and establish relationships between removal effectiveness and parameters in fish processing wastewater which affect UV’s performance. 

The design, construction and commissioning of the treatment system was completed October 2011.  Several challenges arose that have been addressed by the project team and the current expected completion date is May 2012. 

• The original design was double the expected cost resulting in design modifications and a 2nd tendering process. MHC also undertook the management of construction and commissioning as well as the procurement process in-house.  These were very positive steps for the project but caused an eight month delay in the commissioning of the treatment system and the start of testing. 
• The pre-treatment process has not reduced the total suspended solids (TSS), biochimical oxygen demand (BOD) and carbonaceous oxygen demand (COD) to levels required for effective UV sterilization of viruses and bacteria and as a consequence the testing for viral removal has not commenced.  MHC is currently working with the project participants (Worley Parsons and TrojanUV) and a wastewater specialist to determine how to best address this challenge. 

The results of this project have provided many benefits that support the sustainability of the BC aquaculture industry and the seafood industry worldwide.  An immediate and direct result is the improvement in the quality of the processing plant effluent discharged to Hardy Bay.  Other positive results are the proving of the less costly and “green technology” for effluent treatment, as well as, providing an alternative for reduced biosecurity risk from viral disease transmission. The project also has provided the opportunity for testing an established technology in a novel aquaculture setting enabling a Canadian company to access this new market.   

2. Project Description

Introduction

IHNV is a disease that impacts both wild and farmed salmon and non-salmonid wild fish.  In British Columbia, there have been major outbreaks of the virus in 1992-1997 and 2001-2003.  The second outbreak affected 36 farms in the span of 660 days and the economic implications have been significant for the industry as a whole.  For instance, IHNV claimed 70% of Pan Fish farmed salmon in 2002, leading the company to state that the virus is “a major biological risk for the salmon farming industry in BC.” 

As fish from an infected farm can still be processed, release of bloodwater and process wastewater from the plant potentially carrying the virus can accelerate waterborne transmission of the disease both upstream and downstream of the plant.  Containing all bloodwater and processing wastewater for disinfection is a primary means of preventing transmission of IHNV at processing plants.  The recommended procedures state that UV, ozone, and chlorination/dechlorination are considered suitable methods of disinfection.  To date however, the industry has generally favoured chlorination/dechlorination. 

Concerns with respect to chlorine disinfection have arisen and before the free chlorine residual required for disinfection is attained, all organic matter and ammonia (both of which are high in fish processing wastewater) must be oxidized.  Also in seawater, chlorine is 40 to 80 times less effective.  Many plants and farms have found it difficult to achieve and maintain the recommended free chlorine residual levels, possibly for these reasons.  Therefore, the effectiveness of chlorination, and thus the biosecurity of fish farms and processing plants, may be questionable.

The objective of this project was to demonstrate, on a full scale basis, the effectiveness of UV technology for disinfecting fish processing plant wastewater as an alternative/improvement to chlorine disinfection.  For UV disinfection to be effective in wastewater, pre-treatment is required.  Thus, this project indirectly also demonstrates the effectiveness of the pre-treatment system – screening, dissolved air floatation, and filtration.  The findings of this study will be of interest to plants which have pre-treatment and disinfection requirements (as determined by an Environmental Impact Study), such as those discharging into poorly flushed embayed waters.

Within BC, IHNV is considered a serious threat to the provincial aquaculture industry as a whole.  An outbreak of the virus generally transcends corporate property boundaries.  Therefore improved IHNV control in one producer may help prevent the spread of the virus to farms and plants within an entire geographical area.  Through participation in the BC Salmon Farmers Association, knowledge gained from this testing will be readily shared within the BC Aquaculture Industry.

On a national scale, IHNV control may be of less relevance on the east coast, however similar challenges have been experienced there with infectious salmon anemia (ISA).   While the required UV dosages to inactivate different viruses will vary to some degree, the use of pre-treatment and UV disinfection technology for ISA is otherwise identical.  Therefore, improvement of fish processing plant wastewater treatment and UV disinfection technology raises the standard for seafood processing across Canada.
 
Apart from the seafood producers and processors, this project is of interest and potential benefit to commercial suppliers to the aquaculture industry.  TrojanUV, based out of London, Ontario, is an international leader in UV technology.  There is global interest in using UV to inactivate processing plant fish pathogens, however virtually no plants are willing to pioneer the technology.  This project will provide Trojan with a reference installation, which, if successful, will likely see widespread expansion of this technology into the industry as has been experience in other industries.

The most commonly cited misconception within the industry is that UV disinfection does not work for fish processing wastewater.  Concerns raised regarding the technology include poor inactivation rates, difficulty in operation, the need for pre-treatment, and that the technology was tested in the past and did not work.  For UV to be effective, total suspended solids must be low since particles can shield microorganisms from the UV radiation.  Without pre-treatment for solids removal, poor inactivation rates are expected.  High concentrations of iron and manganese can also impact UV performance by absorbing UV light, shielding microorganisms, and fouling bulbs.   For treating primarily bloodwater with high levels of iron, fouling will lead to poor inactivation rates and require manual cleaning.  For facilities requiring pre-treatment with a minor proportion of bloodwater, a UV system with automated cleaning can be expected to perform well.

3. Methods and Deliverables

Phase 1: Design Treatment System - suitable for construction that will treat fish processing wastewater down to required effluent levels as determined by the Environmental Impact Study. 

The following are system requirements for mechanical and chemical removal of BOD and TSS and UV disinfection:

• Removal of large particles through 100 microns screens;
• Removal of suspended solids through dissolved air floatation and chemical coagulant and polymers;
• Polishing of clarified wastewater with 30 micron drum filter prior to UV disinfection; and
• UV disinfection with three Trojan UV units in series each delivering a dosage of 30 mJ/cm2 for a combined dosage of 90 mJ/cm2

Deliverable: Detailed Design Report, construction drawings, and the prepared tender document.
 
Phase 2: Treatment Plant Tendering, Construction, and Commissioning

Deliverable: Building constructed and system installed with drum filter, DAF and UV disinfection.  Building and treatment system was commissioned and functionality confirmed.

Phase 3: Testing

Objectives:

• Effluent parameter for BOD, TSS, and 4-log reduction of viruses;
• Determine relationship between virus log-removal and UV dosage rates to arrive at an optimal UV dose; and
• Determine factors affecting UV effectiveness - transmissivity, TSS and dissolved iron to improve the understanding of UV disinfection performance with fish processing wastewater

Experimental Procedure:

• BOD and TSS evaluations weekly for a period of 8 weeks;
• Bacterial and viral evaluations for 1 week; and
• Analysis of results

Bacterial Evaluation - for each test, a strain of the indicator virus (bacteriophage or equivalent) will be injected upstream of the UV system.  A tracer dye will be injected with the virus to ensure adequate mixing and that virus injected water is collected downstream of the UV system.    Samples will be collected upstream of the UV system and downstream of each of the three UV units.  Triplicate sampling will be conducted for each of the downstream sample locations to minimize variability.  The upstream sample will be sent for analysis of indicator virus MPN, TSS, dissolved iron, and transmissivity.  Downstream samples will be assessed only for indicator virus MPN.
 
Viral Evaluation - The final testing protocol is to verify the UV disinfection technology for fish viruses with similar properties to IHNV.  Similar to the second test protocol, a strain of the fish virus will be injected upstream of the UV system followed by collection of downstream samples. Deliverable: Testing of the treatment system initially indicated high BOD and TSS which affects UV sterilization.  These results led to modification of treatment system design and further testing. 

Phase 4: Communication - transfer of project information to Marine Harvest’s international operations and the BC, national and international aquaculture industry. 

Methods:

• Articles will be written and submitted to Northern Aquaculture, Professional Aquaculture Management, and Norsk Fiske Oppdrett (Norwegian Aquaculture magazine);
• Peer reviewed Journal of Aquaculture Engineering;
• Cooperation with the UV supplier’s efforts to prepare sales documentation or a case study report on the project, if requested;
• Presentation to Marine Harvest Canada and members of the Salmon Farmers Association and New Brunswick Salmon Growers Association prior to a tour of the facility; and
• Summary fact sheet prepared and posted on the Marine Harvest’s website.

4. Status of Project and Future Activities

This project has had challenges which are to be expected when complex, innovative equipment and processes are applied to an existing production system.  These challenges have caused project delays, however the information gained from this additional work will be invaluable when the wastewater treatment system is applied to other situations in the aquaculture industry.

Phase 1: Design Treatment System
All activities for this Phase were successfully completed and the treatment system design was developed and used as a base document for the tendering and construction of the system.  Modifications to the design were included when the cost of the system was deemed prohibitive.

Phase 2: Treatment Plant Tendering, Construction, and Commissioning
The construction and commissioning of the treatment plant was completed by August 2011 and had the following challenges and results:

Challenge 1- Cost of the Treatment System
Once the design was completed, Class A estimates (quotes) were obtained and from these quotes it was ascertained that the treatment system cost was double the original estimates of approximately $2M.

Activities Undertaken to Address Challenge 1

• The treatment system was redesigned and re-tendered.
• MHC undertook the management of procurement and construction in house.  This allowed savings on the management costs and provided MHC with control over the cost of equipment and other system requirements. 

Challenge 2 - Delay of Construction of Treatment System
Due to the challenge described above and the subsequent need to re-design and re-tender, the construction and commissioning of the treatment plant was not completed until August 2011.  The original plan was complete by October 2010 allowing the testing to run October 2010-January 2011. 

Activities Undertaken to Address Challenge 2

• When it was determined that the cost of the treatment system had doubled, MHC decided to move forward as the project general contractor managing the tender process, procurement and construction and commissioning to reduce costs while ensuring the project objectives were met.  While this created an initial delay in the tendering process it has also enabled greater efficiency in subsequent activities.

Result: A detailed design appropriate for wastewater pre-treatment and UV disinfection for aquaculture processing plant applications was completed.

Phase 3: Testing
The testing of the water treatment system was delayed for the reasons stated above and was initiated in October 2011.  As per the project plan, the TSS, BOD and COD testing commenced first with the following challenges. 

Challenge 3 - TSS, BOD and COD Removal
The pre-treatment DAF system was not removing TSS and as a consequence the BOD and COD levels were too high to effectively destroy bacteria and viruses by UV.  The source of the problem was identified as a combination of 1) inadequate mixing of DAF chemicals designed to ensure the particles are suspended; 2) the chemical mixture not appropriate for the effluent characteristics; and 3) the inability to calibrate the DAF to the effluent requirements.  

Current and Future Activities to Address Challenge 3

• MHC has been and continues to work with the chemical supplier, the DAF manufacturer, the firm that designed the treatment system to develop system modifications, to optimize chemical mixtures and to devise procedures that will improve the DAF performance.
• A wastewater treatment specialist with international experience, EPCOR, has been contracted to determine how to best address this issue and a report is expected mid January.  At that point, MHC will implement the required modifications or additions to the treatment system.

Challenge 4 - Virus Removal Testing
The major challenge in confirming the treatment plant effectiveness is determining the IHN virus removal efficiency of the system when the virus is likely not present in the wastewater.  Injection of IHNV strains upstream of the UV system is considered too risky given the potential economic and environmental implications of a release of IHNV into the marine environment.  A non-revertible fish virus with similar properties to IHNV is proprietary. This project initially included viral testing by Microtek and a non-pathogenic virus was to be supplied by this company. At this time another lab is being sourced to complete the testing.

Because the effluent treated by the DAF contains levels of BOD and COD that will reduce the efficacy of the UV system, the tests to ascertain removal of IHNV have been postponed until an effective method of BOD and COD reduction has been installed. 

Current and Future Activities to Address Challenge 4

• Tests to evaluate the efficacy of removal of IHNV are scheduled for March 2012.
• Another source of non-pathogenic virus to be used as a surrogate for IHNV in the testing is currently being sourced.
• A company interested in participating in the project in lieu of Microtek/Pfizer is currently being sought.

A wastewater specialist has been contracted by Marine Harvest Canada to determine what is required to ensure the pre-treatment produces effluent that can be effectively treated by UV.  A report from the wastewater expert is expected mid January 2012 that will define necessary modifications to the system, chemicals and/or procedures.  These modifications are scheduled to be implemented by early February with the testing of the system completed in April 2012.

Result: Standard operating procedures and methods have been developed for both the pre-treatment and DAF technologies that will enhance UV sterilization.  These procedures are specifically for aquaculture processing plant applications.   

5. Conclusion

This project has provided many benefits that support the sustainability of the BC industry and the seafood industry worldwide as well as providing key testing of Canadian technology for a new market. The information collected by this project encourages improved social, environment, biosecurity and financial performance.

Improved Environmental Performance
As a direct result of this project, the impact of the Port Hardy Processing Plant on the surrounding marine waters has been significantly reduced.  The solid particles in the effluent have been removed and the BOD and TSS concentrations are considerably lower.  The plant effluent is now cleaner than the standards require.

This project positively affects the District of Port Hardy, Kwakiutl First Nation, Gwasala First Nation, and Quatsino First Nation. Improving the quality of discharges to Hardy Bay will ensure first Nation aquaculture industries, traditional land uses and recreational and tourism values are maintained.  Enhancing the sustainability of the aquaculture industry in the area also secures employment in this area where employment is largely resource based.

This project has enabled the adoption of a leading edge “green” technology that has positioned Marine Harvest as a corporate citizen concerned with the environment.  Given the negative publicity currently surrounding aquaculture, minimizing the environmental impacts of the industry is a positive step towards public acceptance. 

The knowledge gained from this innovative project will be shared with national and international aquaculture stakeholders, helping the industry to improve its environmental performance and biosecurity, become more sustainable, and ultimately, gain improved public acceptance.

Improved Industry Biosecurity and Reduced Risk from Disease
It is known that during an outbreak viruses can spread rapidly within a geographical area and that fish processing plants can assist in this dissemination.  This project has provided improved IHNV control which has the potential to prevent the spread of the virus to farms and plants within an entire geographical area. The project information will be provided to the BC Salmon Farmers Association for dissemination to other producers which has the potential to improve biosecurity throughout the industry.

This project has accumulated a database of information on the use of pre-treatment and UV disinfection technology for IHN and other viruses which will be provided to the BC Salmon Farmers Association for distribution to the BC industry and nationally.  Improving fish processing plant wastewater raises the standard for seafood processing across Canada.

Improved Industry Sustainability
Despite the demonstrated effectiveness of UV disinfection in numerous municipal and industrial applications, UV has not been adopted within the fish processing industry.  This project has provided the significant benefit in taking the lead in testing and determining processes for application to the BC aquaculture industry.

Commercialization of Canadian Technology and Entry to a New Market
TrojanUV, London, Ontario, is an international leader in UV technology.  This project pioneered the technology for the seafood industry and provided Trojan with a reference installation to support expansion into this new market.