Farmers and land managers have a duty to maintain the health of the environment for which they are responsible. This isn’t just about the fields, crops and grazing for livestock, it’s about making sure that onsite sewage and wastewater treatment facilities are non-polluting for waterways, wildlife and the countryside itself.
It’s not unusual for farms to be off the mains sewer system. By their very nature, farms are in remote locations, with lots of land. Without a mains sewer system, farmers need to make sure they are treating and disposing of their sewage in a way which is safe and legal. This could be through a mix of treating it themselves, possibly reusing it on the farm as fertiliser, and getting it disposed of by a licensed contractor.
If a home or business isn’t connected to the mains sewer, a farmer will have to use either a septic tank, small sewage treatment plant (sometimes called a package treatment plant) or cesspool to collect their sewage.
A septic tank is an underground tank where the solids sink to the bottom and liquid flows out into a drainage filed and allows the effluent to soak into the ground
A sewage treatment plant is a part-mechanical system that treats the liquid so it’s clean enough to go into a river or stream (as long as you have obtained any relevant permissions to discharge).
A cesspool (sometimes called a cesspit) is a sealed tank that collects sewage
These options would be used to deal with the domestic sewage from the farmhouse and any cottages on site. Depending on where cottages are located, a farm may need a sewage treatment plant or septic tank for each home on site, or it may be possible to have a single shared system.
Sewage treatment plants
Sewage treatment plants are the preferred option for most homes, farms and businesses. They work by creating an environment which encourages bacteria to grow and break down the sewage.
Sewage treatment plants are designed to deal with domestic water from your shower, sinks, bath, toilet, washing machine and dishwasher, plus the waste products you would expect to find from them!
Sewage treatment plants are definitely not designed to deal with any agricultural waste, including excess milk, herbicides, pesticides or sheep dip.
They are also not designed to deal with baby wipes or sanitary towels, or food washed down the sink, which is harder for the system to break down.
They are clean and eco-friendly and may be your only choice if you plan to discharge wastewater into a ditch or stream. As the waste leaves the final chamber of the sewage treatment plant to be discharged into the environment, it can be as much as 95% clean, posing no threat to the environment.
Sewage treatment plants generally require a power source, because the majority of them work by pumping in compressed air or by rotating discs.
Tanks for Everything stocks a range of sewage treatment plants in different sizes. Before you go ahead and order one, think about what size you will need. You need to consider the size of each property using the treatment plant and the number of people who will be staying there.
If the sewage treatment plant is going to serve a number of homes on site, it will need to be much bigger. Remember to not just consider the number of people currently living there, think also about the potential occupancy in the future eg a three bedroom house could be home to five people.
The General Binding Rules regulate small sewage discharges and apply to anyone who operates a septic tank or small sewage treatment plant in England. Anyone that operates or plans to install a septic tank or small sewage treatment plant must follow the rules as a minimum. Once you comply with the General Binding Rules, you do not require a permit.
Running a busy farm, it is unlikely you will give the same care and attention to your sewage treatment plant as you do to your livestock or farm machinery, but it is essential that you keep it well maintained and follow the General Binding Rules (see General binding rules: small sewage discharge to the ground - GOV.UK (www.gov.uk). If anything goes wrong with your sewage treatment plant, it could cause costly environmental damage, potentially affecting local wildlife and waterways, as well as your own land and crops.
Sewage sludge as fertiliser
It isn’t possible to empty your sewage treatment plant or septic tank yourself, this should be done by a licenced carrier. However, it is possible to spread treated waste (sewage sludge) on your land. This can be from your own sewage treatment plant or (more likely) imported from elsewhere.
Farmers actually have a vital role to play in recycling sewage sludge (solid matter that’s left behind after wastewater is treated), which is good for the environment and also helps keep their own costs down.
But there are a lot of rules to follow to ensure it is done safely – for your business and livestock, as well as the surrounding countryside, wildlife and waterways. While some contents of sewage sludge are good for soil and plants, others contain potentially toxic elements (PTE), which are only safe below certain levels.
Sewage sludge can supply a large part of the nitrogen or phosphorous that most crops need. It is also a good source of organic matter to improve soils. Liquid sludge releases ammonia nitrogen, which is easily taken up by plants and is good for grasslands.
Both untreated liquid sludge and dewatered treated sludge release nitrogen slowly and the benefits to crops are realised over a relatively long period.
If you produce and spread sludge, you must know the levels of PTE in both the sludge and the soil before spreading it on your land – or agreeing to a contractor spreading it on your land.
Any risks depend on:
- How the sludge has been treated
- Levels of PTE already in the soil
- How the sludge is applied to the soil – injected, spread or worked into it
- The type of crop and what it is used for – whether grazed or harvested
- The weather
- Existing micro-organisms in the soil
You must take particular care before using sludge if:
- You could pollute groundwater or surface water
- You could damage the soil structure by using the wrong spreading equipment
- There are unresolved animal health issues
- Tests have shown there’s a mineral imbalance in the soil, crops or livestock
- The soil type is unsuitable
- You could cause a nuisance from heavy traffic or odour to nearby homes, industry or other road users
- The weather and conditions are unsuitable, including frozen ground, waterlogged fields or an adverse weather forecast
You must not spread untreated sludge on land. You must inject or work it into the soil.
You should also plan carefully when and where to spread it. You mustn’t use treated or untreated sludge on growing fruit and vegetable crops or under permanent glasshouses or polytunnels. In addition, you mustn’t use untreated sludge in orchards.
You must make sure that there is no risk of livestock ingesting any sludge when it is spread.
Help from water companies
Water companies around the UK will supply treated sludge with the excess water removed (also known as biosolids cake or treated sludge cake) to farmers to use as fertiliser. Sludge cake can improve both the water-retaining capacity and structure of soil.
Severn Trent Water, for example, recycles nearly 600,000 tonnes of biosolids as a safe fertiliser. It produces enough fertiliser to cover around 30,000 hectares of land and completes over 3,000 soil samples to ensure the fertiliser is right for the land.
The company has a dedicated farm liaison officer, who will discuss business requirements and particular crops. It will even send out specialised spreading teams to ensure the fertiliser is spread safely.
If you would like to use sludge as a fertiliser, contact your local water company to see what options it offers.
Protecting the environment
While sludge is undoubtedly beneficial to farmers and also an environmentally sound way of disposing of a by-product of wastewater, there are potential environmental risks.
Before using sludge, it is essential to check the site to ensure it can’t run off onto adjacent land, roads or into rivers or waterways.
If it is raining enough to cause run-off, you must stop spreading.
To avoid run-off from sloping land, you must avoid spreading on ground which is frozen, waterlogged or very dry, as well as land which is near water supply sources.
Good farming practices will help reduce the risks of water pollution. For example, you can reduce the risk of nitrogen getting into water supplies by adjusting the timing and rates of application according to the demands of a particular crop.
When faced with the challenges of farming and running a business, as well as dealing with a whole range of agricultural waste, from pesticides to sheep dip and waste silage to unused animal medicines, it is easy to forget about the importance of carefully managing sewage on a farm. Tanks For Everything stocks a wide range of products for the safe storage of chemicals, waste oils and even silage tanks.
Unmanaged sewage has the potential to cause expensive environmental damage. But by using a sewage treatment plant for the farmhouse and carefully following the rules around spreading sludge, sewage can actually prove to be a valuable resource for a farm.