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Success of HACCP in the drinking water industry: can it be adapted to reuse schemes?\n



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Success Of HACCP In The Drinking Water Industry - Can It Be Adapted To Reuse Schemes ? David Cunliffe, Principal Water Quality Adviser, Department of Human Services (SA)

David.Cunliffe@dhs.sa.gov.au Melita Stevens, Principal Scientist, Melbourne Water melita.stevens@melbournewater.com.au

EXECUTIVE SUMMARY

Preventive risk management systems are recognised as best practice for providing quality assurance across a broad range of industries. In recent years this approach has attracted interest in the water industry. Initially the interest was focussed on the production of safe drinking water. Guidance on development of risk management systems has been developed for inclusion in the Australian Drinking Water Guidelines in the form of the Framework for Drinking Water Quality Management (the Framework) and as Water Safety Plans (WSPs) for inclusion in the third edition of the WHO Guidelines for Drinking-water Quality.

Both the Framework and WSPs, while purpose-designed for management of drinking water supplies, are based on the Hazard Analysis and Critical Control Point (HACCP) system which was developed to ensure food safety and has been adopted internationally by Codex Alimentarius. In Australia drinking water is recognised as a food.

Each of the systems incorporate identification of significant hazards, assessment of the risks that the hazards pose to product safety, establishment of control measures to prevent or minimise the risks and a system of monitoring to ensure that the control measures are always effective. The systems are designed to ensure, wherever possible, if failures occur that they will be detected before supply to consumers.

The same principles used to supply safe drinking water can be applied to wastewater and water reuse. WHO has already signalled that a common approach to risk management should be adopted for water, wastewater and reuse and similar approach is proposed in Australia.

In well-operated systems, implementation of risk management plans such as the Framework and WSPs provides a structure for organisation of existing practices in a cohesive and systematic plan. The Virginia Pipeline Scheme in South Australia and the Eastern Treatment Plant in Melbourne are presented as examples of how design and management of an existing scheme can be described in terms of a HACCP-based plan.

HACCP-based systems are appropriate for wastewater and water reuse. In addition where water is reused for irrigation there could be commercial benefits/requirements in implementing HACCP based systems.

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INTRODUCTION

Implementation of a systematic risk management approach is recognized as an integral part of good practice across a broad range of activities and industries. The first example of this arose from the development of the Hazard Analysis and Critical Control Point (HACCP) system in the 1960s by NASA and the Pilsbury Company to minimise the risk of food-borne illness for astronauts (NASA 1991). The HACCP system was adopted internationally by Codex Alimentarius in 1993 as best practice for ensuring food safety.

A number of factors occurred in the late 1990s demonstrating that risk management systems were required in the water industry. There was growing concern in Australia about misuse of documents such as the Australian Drinking Water Guidelines and the WHO Guidelines for Drinking-water Quality. These guidelines contain a great deal of information on effective system operation and application of control measures in the form of the multibarrier approach. However, there was an increasing tendency to ignore this information and to rely on end-product compliance testing and adherence to guideline values as a basis for management and health decisions.

Management based on compliance testing is not an effective way of managing risk. Analysis of drinking water quality takes time and exceedance of guideline values is only detected after water has already been supplied to consumers. Only a very small proportion of water can be tested and there are a range of parameters for which there are no practical test procedures. The 1998 Sydney Water Incident provided a demonstration of these shortcomings (McClellan, 1998). Internationally other incidents had far more severe outcomes. In Walkerton, Canada in 2000, over 200 people became ill and 7 people died as a result of poor management (O’Connor, 2002a and 2002b).

An additional reason for adopting a risk management approach was provided by confirmation during development of uniform food legislation for Australia that drinking water is a food.

Between 1999 and 2002 a Framework for Drinking Water Quality Management (the Framework) was developed for inclusion in the Australian Drinking Water Guidelines. Development of the Framework was undertaken with widespread support from water and health agencies across Australia and included workshops, pilot trials and extensive agency and public consultation.

The World Health Organisation (WHO) has also developed risk management guidance in the form of Water Safety Plans (WSPs) for inclusion in the third edition of the WHO Guidelines for Drinking-water Quality, which is due for publication in 2003.

The Framework and WSPs have been purpose-designed to meet the particular requirements related to supply of drinking water. Both include the HACCP principles and are consistent with ISO 9001 and 14001.

Success of HACCP/Risk Management in Australia Widespread support for development of the Framework was due to recognition by water and health agencies that systematic risk management is essential for assurance of drinking water quality. HACCP and HACCP-based systems such as the Framework and WSPs provide a structure for developing risk management plans that can be applied to all water supplies irrespective of size. For larger supplies they formalise and organise existing procedures into a systematic and accessible package that can be easily communicated

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both internally and externally to other agencies, regulators and consumers. In some cases, application leads to identification of gaps and the need for improvement.

For smaller supplies that are often “overlooked”, application provides a basic assessment of needs and an organisational structure. Analysis of almost 2000 rural and remote supplies in Australia identified lack of management as a bigger threat to drinking water quality than inadequate monitoring, poor source water quality or poor treatment.

Risk management systems have either been established or are being developed for the Capital city water supplies. Some authorities are adopting the Framework as written while others have followed a classical HACCP approach with basically the same outcome. This is consistent with the flexible approach incorporated within the Framework.

Implementation has also commenced in a number of smaller urban centres and rural areas. In South Australia work has begun on applying the Framework to remote indigenous supplies (supplying as few as 50 people). The Framework approach has also been incorporated into guidance on management of domestic rainwater tanks.

What is HACCP? There are 12 steps in HACCP, including 5 preliminary steps and 7 principles as shown in Table 1.

Table 1 The twelve steps of HACCP

Step 1 Assemble HACCP Team The HACCP Team plan, develop, verify and implement the HACCP plan. Generally comprises multi-disciplinary people (maintenance, operations, sanitation, quality control, marketing, chemists, microbiologists etc.) knowledgeable of the process and product. Step 2 Describe Product

A full description of the product is documented. This description may include: water source; treatment processes; storage and distribution; and any special considerations to maintain product safety. Step 3 Identify Intended Use

The expected use of the product is documented including: how the product is to be used; consumer instructions for product use; and who the product is intended for. Step 4 Construct Flow Diagram Flow diagram must clearly indicate all process steps in the operation. The flow chart must state when the company’s responsibility starts (bulk treated water, raw source water) and ends (at the meter box, at consumer tap). Steps prior to and after the organisation’s direct responsibility should also be included. Step 5 Confirmation of Flow Diagram The HACCP team confirms that the flow diagram is both complete and accurate as it is used in the hazard analysis. The best validation is to walk through and verify the set up of the system and processes. If this is not possible, those with operational knowledge of the system can validate the flow diagram. Step 6 Conduct a Hazard Analysis Principle 1

A significant hazard is one that must be prevented, eliminated or reduced to an acceptable level to produce safe drinking water. Significant hazards; associated control measures; modifications to improve safety are identified as a basis for determining which control measures become critical control points. Step 7 Determine Critical Control Points (CCPs) Principle 2

A CCP is a point, step or procedure at which control can be applied and a hazard can be prevented, eliminated, or reduced to acceptable levels. The decision tree recommended by Codex may be used to determine if a process step is a CCP. Step 8 Establish Critical Limits Principle 3

Critical limits are assigned to each control measure at a CCP. A critical limit defines the cut off to ensure product safety. If a critical limit is not met then the hazard is not controlled and corrective action is taken. Step 9 Monitoring Principle 4

Monitoring is planned observations or measurements to provide a record. All critical limits have associated monitoring activity to ensure that the critical limit is met. If monitoring indicates that the critical limit has not been met, then corrective action must be taken.

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Step 10 Establish Corrective Actions Principle 5

Corrective actions ensure that the CCP is brought under control. Corrective actions can include: immediate action, responsibility for corrective action, disposition of product and the root cause of the problem. Step 11 Establish Verification Procedures Principle 6

Verification is the use of methods, procedures, or tests to determine if the HACCP system is in compliance and confirms that the system follows the HACCP plan and that identified hazards, CCPs and critical limits are appropriate. Step 12 Establish Documentation and Record Keeping Principle 7 Documentation is required as proof of compliance to the HACCP plan and provide a legal defence for due diligence. HACCP records should be dated and signed. Records should provide product traceability.

Application of HACCP to Reuse Many of the issues related to drinking water also apply to other types of water including, reclaimed water, rainwater, greywater, recreational water and stormwater. WHO has already signalled its intent to adopt a harmonised approach across a range of water uses (WHO, 2001).

The themes are consistent; all waters and wastewaters are threatened by a range of hazards that require identification, risk assessment, the application of control measures, monitoring and where necessary corrective action. In all cases a preventive risk management approach based on HACCP principles is preferable to basing management on end-point monitoring.

Compared to many drinking water supplies the source of reclaimed water (sewage) is relatively well defined as are the range of potential hazards. In addition existing reclaimed water guidelines include lists of potential control measures such as: • trade waste policies • primary, secondary and tertiary treatment • disinfection • on-site controls and • use restrictions.

Implementation of a HACCP-based approach simply provides a structure for organisation of existing practices into a cohesive and systematic plan. In addition, as for drinking water there is a link to food. Irrigation of food crops with reuse water is likely to lead to increased commercial pressures from purchasers for implementation of HACCP-based systems.

Virginia Pipeline Scheme (VPS) The original design and management system for the VPS was completed in 1998/99. Although a structured HACCP approach was not applied at the time the principles of preventive risk management were applied and in manner that fits easily with the elements of HACCP.

Health-based targets A first step in applying a HACCP-based approach is to define safety in terms of health-based targets. The VPS was designed to provide reclaimed water for unrestricted irrigation of food crops. Consumer exposure was determined to be a maximum of 10 mL based on measurements of volumes of reclaimed water that cling to lettuce leaves after irrigation (Shuval et al 1996).

Using risk assessment data from a number of sources (see Florida Dept of Environment Protection, 1998) it can be calculated that pathogen concentrations equating to a 1x10-4 risk of illness are as shown in Table 2.

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Table 2 Health-based targets (pathogen concentrations) for food crop irrigation

Organism Number per 50L for 1x10-4 risk

Rotavirus 0.8

Echovirus 250

Cryptosporidium 110

Giardia 25

Shuval et al (1996) using an assumption of a 3 log pathogen reduction between irrigation and consumption assessed the risk from eating salad vegetables irrigated with WHO Guideline compliant reclaimed water (< 1000 E.coli per 100 mL) to be less than 1x10-5 for enteric viruses.

Taking the more conservative measure approach shown in Table 2 health-based targets adopted for the VPS were that reclaimed water should contain less than 1 virus, Cryptosporidium oocyst or Giardia cyst per 50 Litres.

The VPS and HACCP The design and management plan for the VPS was developed using a preventive risk management approach. The slightly unconventional design of the plant (primary treatment, secondary treatment, lagoons, tertiary treatment and disinfection was assessed as providing greater assurance of quality than a conventional tertiary treatment plant. The lagoons were retained in the final design because of the likelihood of pathogen inactivation/removal and also because the lagoons provided a buffering capacity against any short term spikes of chemical or microbial contamination.

Table 3 demonstrates how the process of developing the management and design of the VPS fits easily under the 12 steps of HACCP. Table 3 shows that providing a preventive risk management approach is adopted in the design of water reuse schemes application of a HACCP-based system provides a structure for the process. Using an established system has advantages in communicating the outcomes to other agencies, growers, buyers and consumers.Using a “system” ensures that a consistent approach is adopted in the design and management of all schemes. It also ensures that the selection of control measures is commensurate with the level of risk. This has significant economic implications.

HACCP Accreditation of Wastewater Treatment Plants - Eastern Treatment Plant Melbourne The Eastern Treatment Plant produces 500 ML of secondary treated effluent daily that is primarily discharged to receiving marine waters. A small amount of effluent is reused for local agriculture and biosolids are stored on-site and reused mixed with soil.

The Eastern Treatment Plant is to be upgraded to tertiary treatment and as part of the EPA works approval, a risk management plan for the existing and future plant is to be developed. A HACCP plan, with a view to have the treatment plant independently certified has been produced. The effluent from the upgraded treatment plant will be Class A (unrestricted use) with end users identified as the marine receiving environment and users of the treated effluent. Table 4 provides a summary of the elements of HACCP identified in the development of a management plan.

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Table 3 Description of the VPS management plan in terms of the 12 HACCP steps

HACCP Step Activity

Assemble team • DHS Public Health Scientists • EPA • SA Water Engineers and Scientists • United Water (Operators of Plant) • Water Reticulation Systems (Virginia) -operators of distribution system.

Describe product • Metropolitan WWTP taking largely domestic waste with some commercial and light industrial waste. No pharmaceutical wastes. • Secondary treatment plant (with trickling filters) • Lagoon Storage (16 days minimum detention) • Dissolved Air Flotation and Filtration Plant • Chlorination and chlorine contact tank • Distribution system including open storage, pipeline and on-site storages • Spray irrigation

Identify intended use • Unrestricted irrigation of food crops including salad vegetables Construct flow diagram • Detailed plans of the treatment plant, the distribution system and the on-site

irrigation management plans provided by SA Water and WRS (V)

Confirm flow diagram • Field surveys undertaken by approving authorities Conduct a hazard analysis (and risk assessment) (Principle 1)

• Human wastewater contains high numbers of enteric bacteria, viruses and protozoa. High risk

• Inputs to plant examined for chemical inputs. Over 200 priority chemicals investigated for health and aesthetic impacts. Chemicals included potential endocrine disruptors, cyanobacterial toxins, chlorination byproducts Low-moderate risk. Highest risk from unlicensed/illegal discharges Determine critical control points (Principle 2)

• Trade waste program • Lagoon storage • DAFF treatment plant • Chlorination • On-site controls

Establish critical limits (Principle 3) • Lagoon storage - minimum storage 16 days • DAFF treatment plant - turbidity limits on individual filters and total effluent

• Chlorination - constant dosing, minimum residual, • Signage, colour coding of pipework, air gaps

Monitoring (Principle 4)

• Flow measurements (continuous) • Turbidity - continuous turbidity monitoring with 24hr alarm system • Chlorinator - continuous monitoring of operation and minimum residual monitoring with 24hr alarm system

• Regular inspections by WRS(V) and independent audit

Establish corrective actions (Principle 5)

• If failure of storage time occurs supply of reclaimed water stopped or treatment enhanced. If filtration or chlorination fails supply of reclaimed water stops automatically. Establish validation/verification procedures (Principle 6)

• Validation was undertaken during precommissioning and commissioning to demonstrate that the critical control points were effective in ensuring that health-based performance targets were met. In terms of microbiological quality this meant (<1 virus, Giardia, Cryptosporidium per 50 L and < 10 E.coli per 100 mL)

• Verification includes routine analysis for microbiological and chemical quality of reclaimed water. Regular review of records. Annual review/audit of all records

• Crop testing

Establish Documentation (Principle 7)

• Records of all monitoring must be retained and be available for inspection at any time. Results reported on a monthly/quarterly basis to DHS

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Table 4 Eastern Treatment Plant HACCP Summary

Assemble Team • Quality systems coordinator • Manager, Eastern Treatment Plant • Manager operations • Recycled water reuse officer • Environmental management systems coordinator • Marketing manager, Environmental Business Development • Liaison with recycled water customers, retail water companies and biosolids customers Describe the product • Raw sewage from eastern and south eastern suburbs. Sewage contains discharge from domestic premises and

trade waste for industry. Trade waste can be high in grease and metals. • Secondary treatment (screening, primary clarification, aerated biological treatment, secondary clarification, disinfection) • Effluent discharged to Bass Strait. • Additional inputs to outfall from local treatment plants • Effluent meets requirements in EPA licence Intended use • For discharge to marine environment, for reuse as Class C, for biosolid stockpiles as Grade C2 Construct flow diagram • Detailed plans of plant retained in HACCP plan Verify flow diagram • Plan verified by HACCP team at team workshop. Conduct hazard analysis (and risk assessment) (Principle 1) • High Risk includes: interface with retailers, effluent contains human pathogens or high levels of chemicals;

contaminants from sewage disabling normal biological processes at plat; major contaminant from illegal discharge; carryover of solids; sludge resuspension. Identify critical control points (Principle 2) • Interface with retailers, domestic sewage/trade waste • Aeration tanks • Secondary clarification tanks • Chlorine dosing • Biosolids sludge stockpile Define critical limits (Principle 3) • Interface with retailer - Critical limits ammonia <40mg/L, COD <960 mg/L • Aeration tanks, failure of blowers - DO <0.4 mg/L or >2.5 mg/L • Secondary clarification tanks, carryover of solids - Turbidity not greater than 25 NTU for 12 hours • Chlorine dosing, failure to dose - Chlorine residual between 0.1 - 0.9 mg/L • Biosolids sludge stockpile, failure to comply - 3 year age of sludge stockpile batch Monitoring (Principle 4) • Interface with retailer - Process monitoring with autosamplers, flow weight comparison, compliance monitoring by NATA certified laboratory • Aeration tanks - DO online monitoring, process monitoring with auto sampler - COD, SS, Ammonia • Secondary clarification tanks - online turbidity monitoring, visual inspection • Chlorine dosing - Online continuous flow and chlorine residual. Micro testing for licence requirement. • Biosolids sludge stockpile - Microbiological testing of stockpiles. Corrective Action (Principle 5) • Interface with retailer - Toxic dump to sewer contingency plan, retail water company notification. • Aeration tanks - Loss of secondary system contingency plan, duty operator conducts on-screen investigation • Secondary clarification tanks - Notification of process manager, review of upstream controls, stops pumps • Chlorine dosing - Manual dosing of chlorine, loss of supply of commodities contingency plan, emergency maintenance • Biosolids stockpile - Product recall Establish validation/verification procedures (Principle 6) • Interface with retailer - Annual plant capacity statement. • Aeration tanks - Historical process monitoring of BOD • Secondary clarification tanks - Historical process monitoring of SS reduction in Secondary system. Plant design parameters. • Chlorine dosing - Microorganisms in outfall meets EPA requirements, historical data. • Biosolids stockpile - Recording sludge and stockpile batch location, audit of customer contract. Documentation • Interface with retailers - Laboratory results, trade waste management meetings. Plant capability statement report. • Aeration tanks - SCADA log books, operator handover, weekly process control meeting, HANSEN database (same for secondary clarification tanks) • Chlorine dosing - SCADA log books, operator reports, NATA reports, HANSEN database, Annual monitoring report. • Biosolids stockpile - Audit reports, laboratory records

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CONCLUSION

The Australian Framework, WHO Water Safety Plans and HACCP are all variations on the same theme of preventive risk management. The common aim is to implement appropriate control to provide continuous quality assurance. HACCP has already been adopted as a standard requirement in the food industry and the Framework and WSPs are carrying the concept of risk management systems into the drinking water industry. WHO and peak Australian health and water agencies are proposing that a similar approach should be applied to other waters, wastewaters and reuse.

Support for the use of risk management plans for drinking water supplies has been widespread with water and health agencies both recognising the benefits. Implementation has commenced.

HACCP-based systems are equally applicable to wastewaters and reuse. Implementation will provide an organised and logical structure for quality assurance. In the case of existing developments such as the VPS, HACCP-based management plans formalise and organise existing procedures into a systematic and accessible package that can be easily communicated both internally and externally to other agencies and the public. For future developments the application of risk management systems will ensure that a consistent approach is applied and that the selection of treatment processes and other control measures will be commensurate with risk. The most important benefit is an increased confidence in quality assurance.

In future there may be commercial pressures to apply HACCP-based systems to water reused for irrigation. Operators of wastewater treatment plants are also examining the advantages of applying HACCP-based systems both in terms of providing an improved management structure as well as gaining accreditation.

REFERENCES

Florida Department of Environmental Protection (1998). Risk Impact Statement. Phase II Revisions to Chapter 62-610, F.A.C. Docket No.95-08R.

McClellan, P. (1998). Sydney Water Inquiry. NSW Premier’ Department.

NASA (1991). A Dividend in Food Safety. Spinoff 1991. NASA Technical Report ID 20020086314.

NHMRC/NRMMC (2002). Draft Australian Drinking Water Guidelines. NHMRC, Canberra.

O’Connor, D.R. (2002a). Report of the Walkteron Inquiry, Part 1. The events of May 2000 and related issues. The Attorney General of Ontario, Toronto, The Walkerton Inquiry.

O’Connor, D.R. (2002b). Report of the Walkerton Inquiry, Part 2. A strategy for safe drinking water. The Attorney General of Ontario, Toronto, The Walkerton Inquiry.

Shuval, H., Lampert, Y. and Fattal, B. (1997). Development of a risk assessment approach for evaluating wastewater reuse standards for agriculture. Water Science and Technology 35 (11-12) 15-20.

WHO (2001). Water Quality: Guidelines Standards and Health. IWA Publishing, London.

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WHO (2003). Draft Guidelines for Drinking-water Quality. Third edition. WHO, Geneva.