Industry best practice manual for water quality management and sterilisation on-farm

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Microbial treatment

Performance goal: Water treatment avoids or minimises microbial impacts from the water on meat chicken farms.
Description: Microbial contamination is associated with inadequate treatment of water supplies and unsatisfactory management of drinking water distribution in meat chicken farms.

There are many infectious diseases caused by pathogenic bacteria, viruses, protozoa and helminths that can are spread to chickens via water, including: Chronic respiratory disease (CRD), Colibacillosis, Avian cholera, Fowl typhoid, Newcastle disease, Infectious bronchitis, Marek’s disease, Avian encephalomyelitis, Gumboro disease, Histomoniasis and Coccidiosis.

Microbial contamination can be introduced from the source of water or elsewhere in the water distribution system and is often caused by faecal contamination related to birds, humans (water sewage treatment plants, sewage overflow, etc.), domesticated animals (manure spreading, pit stock overflow), or wildlife.

This disinfection performance criterion is ideally measured after all pre-treatment performance criteria have been met and water has been disinfected.
Performance criteria: Microbial impacts are controlled.

Best practice level: 0CFU E. coli/ml based on laboratory or on-farm testing.

Maximum acceptable level: 0CFU E. coli/ml based on laboratory or on-farm testing.
Minimum requirements
Water is disinfected daily. See Tables 19 and 20 (below) for a comparison of the effectiveness of treatments against microbial agents.

Water disinfection with one of the following oxidants: chlorine, chloramine, chlorine dioxide, bromine, iodine, ozone, hydrogen peroxide, etc.

If ultraviolet light disinfection is being used, an oxidant disinfectant is used as a secondary disinfectant after UV treatment to provide a residual.

ORP disinfection of 650mV is measured at the far end of the water line (i.e. the last drinker).

A disinfectant residual of 1–2ppm is achieved at the far end of the water line (i.e. the last drinker).
Best practice options
All water is filtered before disinfection down to a 10 micron equivalent pore size.
Water with high concentration levels of iron and manganese is filtered after disinfection.

To oxidize iron requires above pH 7 and a minimum of 20 minutes reaction time. Manganese needs a pH of above 8 and a much longer reaction time.
Sufficient Ct to inactive pathogens of concern.
Automated disinfection dosing system.
Online disinfection residual monitoring system.
Replacement disinfectant and associated chemicals and consumable parts on standby.
Backup power and duplicate facilities treat water.

Table 19. Effectiveness of disinfection treatments against bacteria, viruses and protozoa

Effectiveness againstBactericidalViricidalProtozocidal
Disinfection treatment
Chlorine dioxideGoodGoodModerate
Chlorobromination and brominationGoodPoorPoor
Peracetic acidGoodGoodModerate
Hydrogen peroxideGoodGoodModerate
Potassium permanganateGoodGoodPoor

Table 20. Indicative log removals of enteric pathogens and indicator organisms (adapted from NRMMC et al., 2008)

TreatmentIndicative log reductions
Escherichia coliEnteric bacteria (e.g. Campylobacter)Enteric virusesPhageGiardiaCryptosporidiumClostridium perfringensHelminths
Dual media filtration0–1.00–1.00.5–3.01.0–4.01.0–3.01.5–2.50–1.02.0–3.0
Membrane filtration3.5–>6.03.5–>6.00.5–>6.03–>6.0>6.0>6.0>6.0>6.0
Ultrafiltration, nanofiltration, reverse osmosis>6.0>6.0>6.0>6.0>6.0>6.0>6.0>6.0
Reservoir storage1.0–5.01.0–5.01.0–4.01.0–4.03.0–4.01.0–3.5N/A1.5–>3.0
Ultraviolet light2.0–>4.02.0–>4.01.0–>3.03.0–6.0>3.0>3.0N/AN/A
High-level ultraviolet>6.0>6.0>6.0>6.0>6.0>6.0N/AN/A
Advanced oxidation>6.0>6.0>6.0>6.0>6.0>6.0N/AN/A
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