Making effluent systems safe
Dairy effluent systems can be hazardous if they are poorly designed or managed.
Farm safety and accident prevention should be the highest priority on the farm, ensuring the farm surrounds are as safe as possible for:
- children
- workers
- visitors
- contractors
- livestock
- pets.
The following information is provided for guidance. It is important that every farmer consults widely, critically assesses their own situation for risks and takes adequate measures to control any problems identified.
All employees, contractors and children should be made aware of the dangers different effluent system components may pose.
Safe use of all components of the effluent system should be included in induction activities.
Sumps and solids traps
These structures contain liquid and sludge. They are usually steep-sided, so they should either be covered with safety grating or be surrounded by a safety fence, including locking gate, to exclude children, pets and livestock. If young children live on the farm or visit, the construction of a fence and gate to swimming pool surrounds standards (Australian Standard 1926.1) may be warranted.
Sumps and pumps should be designed for ease of cleanout, with suitable machinery access available. Farm machinery operators removing sludge from these structures should be aware of children and other people in the vicinity.
Ponds
Every effort should be made to make ponds and their access points safe.
The water depth in ponds can range from 1 m to 6 m, which poses a drowning hazard.
Effluent ponds are usually constructed with internal batter slopes of 2:1 or 3:1 but can on occasion have steeper internal batters of 1:1, depending on where the pond has been sited. Steep batters increase the instability of the structure and can be extremely slippery.
These factors make it relatively easy to slip into a pond and extremely difficult to escape.
Ponds may form a crust of solid-looking material. This can occur if they are designed to do this or due to substandard management practices that don’t include a suitable and regular desludging program. This surface crust can often grow weeds, grasses and even small saplings in some cases, giving an illusion of a stable surface.
As most pond surrounds are not usually grazed, tall weeds tend to establish, hiding the presence of water and making it difficult to locate the edge of the pond. Indicators can be placed around the edge of the pond to show the pond edge.
Pond maintenance or desludging should be conducted with extreme caution, as unstable and narrow banks may collapse under the weight of machinery. Pond stirrers and power take-off driven pumps must also be guarded. It’s also advisable to chock the machinery’s wheels, as the constant vibration may cause it to move closer to the pond's edge.
Farm children, employees and contractors need to be made aware of the hazards of effluent ponds and particular attention needs to be paid to warning visiting children. Ponds should be fenced as soon as construction has been completed, to reduce the risk to young children and stock. Appropriate signs warning of deep water or showing relevant hazard symbols are also warranted. Signs are available from safety equipment suppliers.
Some common safety tips:
- Use goats or sheep to graze the pond surrounds, but not cattle or horses.
- Mowing and spraying herbicides will control excessive vegetation around ponds.
- Erect appropriate fencing around the pond.
- Locate and mark the pond edge before accessing by machinery.
- Encourage the establishment of grasses on external batters to help stabilise the banks. However, trees and shrubs should not be allowed to establish close to the pond, as tree roots can compromise the pond structure.
- Ensure any pontoons on the pond have adequate buoyancy and are securely fixed to banks. Consider if pontoons can be designed to be removed from the pond surface for safer maintenance.
- Use long extension poles to collect effluent samples for nutrient analysis.
- Maintain the pond bank by regularly monitoring and repairing cracks, erosion or damage caused by machinery or flooding events.
Yard wash systems
Generally, the dairy yard and other infrastructure outside the dairy shed are washed using hoses, hydrants or flood wash systems. All these systems have associated safety concerns and training should be provided for staff during induction on safe use of this equipment.
During use hoses can be hard to hold onto and can cause injury if they become loose. When not in use they should be stored away from high-traffic areas to avoid a trip hazard.
Flood wash tanks should be installed on solid and stable foundations due to their significant weight. They should also have appropriate guarding on outlets and rudders to prevent injury to dairy operators and stock.
Hydrant washing systems operate at high pressure, discharging large volumes of water. Nozzles and couplings have been known to fly around if not handled correctly. Safe operation of this equipment should be included in induction of new staff. Children or inexperienced operators should not operate these systems.
Recycling effluent water from a multiple-pond system back to wash the yard is a common way to reduce the daily freshwater requirement for the dairy and other infrastructure. This significantly reduces the storage pond volume required, as well as providing a reliable water source for this use.
Recycling effluent water from sumps, trafficable solid traps and even smaller single ponds is not encouraged. Recycled effluent from these sources is usually of a poorer quality, which tends to block pumps and pipes and be more odorous. As well as this, it can promote slime and algae deposits on yards, creating a slippery surface for stock and operators.
The risk to the operator from aerosols when using recycled effluent has not been studied. Therefore, the best option if using recycled effluent for yard wash is to use a system where the operator doesn’t have direct contact with the effluent, such as a flood wash system.
Pumps
The management of dairy effluent often requires some type of pump/s to move effluent around the system and to enable effluent and the nutrients it contains to be returned to pastures. The pump selected and where it is located will vary significantly, depending on the farm layout and how effluent is to be managed.
Some common safety tips:
- Use only a qualified electrician to install all electrical components.
- Install weatherproof and waterproof switches.
- Allow adequate spacing around the pump for maintenance.
- Guard all moving parts, such as shafts and impellers.
- Ensure all staff are provided guidance on how to use the different pumps during induction.
- Be conscious of manual handling issues when removing pumps or moving travelling irrigators.
- Ensure all electrical wiring is protected and far enough away from any water sources.
Human health
Dairy effluent should not be a threat to human health, provided appropriate hygienic practices are followed. These include:
- not smoking, eating or drinking while in the dairy shed or around other infrastructure
- washing hands and clothing after completion of a task involving contact with effluent and manure.
As aerosols can be generated by hydrants and manure sprinklers, it is wise to avoid areas where effluent can be inhaled or is likely to settle on the skin.
Where possible, avoid direct exposure to effluent. For example, if practical for yard washing use a flood wash system rather than handheld hoses with recycled effluent.
Dairy shed operators should wear appropriate personal protective clothing, such as aprons, gloves and footwear with good traction.
Confined spaces
Dairy operators should be aware of regulations associated with confined spaces, as the effluent system may have several. Examples are:
- storage tanks and other tank-like compartments
- pits
- silos
- pipes
- wells.
These structures may form part of an effluent system. However, where an alternative option is available, confined spaces should be excluded from effluent systems.
Manure and effluent machinery and equipment
The ongoing management of dairy effluent systems requires the use of various contractors and a range of machinery including excavators, bulldozers, slurry tankers, solid manure spreaders, bobcats, frontend loaders, pond agitators, umbilical distribution tractors and sprinklers. Farmers can minimise risks by:
- maintaining maintenance schedules
- providing farm induction to site visitors
- ensuring all laneways and access points safely accommodate machinery and equipment
- providing a farm biosecurity plan
- ensuring farm standard operating procedures are available and followed.
Effluent management plans
The development of an effluent management plan to assist with the operation, maintenance and management of the dairy effluent system is recommended. The plan provides specific technical, maintenance and management options relevant to the individual farm, ensuring productive and safe use of dairy effluent.
An Effluent system designer can help develop an effluent management plan.
More information
More information on safety covering broader dairy operations can be found in:
- Effluent and Manure Management Database for the Australian Dairy Industry, 2008, Dairy Australia:
- https://www.dairyaustralia.com.au/resource-repository/2020/07/09/effluent-and-manure-management-database-2008
- Dairy Safety: A Practical Guide 2017. WorkSafe Victoria: https://www.worksafe.vic.gov.au/resources/dairy-safety-practical-safety-guide Confined spaces: Safety basics. WorkSafe Victoria:
- https://www.worksafe.vic.gov.au/confined-spaces-safety-basics