Can a farmer empty my septic tank?

The simple answer is NO, as it is highly unlikely that he complies with the regulations below:

The Farmer MUST be a Registered Waste Carrier.

Untreated sewage treatment plant or septic tank waste has been banned from beeing spread on all agricultural land since 2005. See:

http://www.adas.co.uk/LinkClick.aspx?fileticket=f_CX7x_v4nY%3D&tabid=211&mid=664

Farmers now only receive payments under the Common Agricultural Policy (CAP) if they achieve and maintain certain standards on:

These standards are known as 'cross compliance'.

If you supply or spread sludge to agricultural land, you must meet the requirements of the Sludge (Use in Agriculture) Regulations. You must comply with these regulations in order to meet the requirements of the cross compliance rules of the single farm payment scheme

You must only use sewage sludge that has been tested according to the Sludge Regulations. You must check that you do not exceed the limit on the average annual rate of addition of metals in the sludge.

You must not spread sewage sludge on a field unless you have tested the soil according to the Sludge Regulations. This includes checking that the limit on the concentration of metals in the soil will not be exceeded by spreading the sludge.

You must not spread sludge on land that has a soil pH of less than five.

You must not use sewage sludge or septic tank sludge:

• when fruit, other than fruit trees, or vegetables are growing or are to be harvested in the soil
• without taking the nutrient needs of the plants into account
• if it will damage the quality of the soil, surface water or groundwater.

The farmer must provide the septic tank owner with information of any past sludge use from a different source. This should include details of where, when and how much sewage sludge was used and who supplied it. 

After sewage sludge or septic tank sludge has been applied, you must not:

• graze animals or harvest forage crops for at least three weeks
• harvest fruit and vegetable crops that are grown in direct contact with the soil and that are normally eaten raw for at least 10 months.

After sewage sludge or septic tank sludge has been applied, you must:

• Work untreated sludge into the soil as soon as possible. Untreated sludge is sludge or septic tank sludge that has not undergone biological, chemical or heat treatment, long-term storage or a process to reduce its fermentability and health hazards.
• Inform your environmental regulator immediately if sewage sludge enters a watercourse.

Any contravention of any of the above regulations breaks the rules of cross compliance and risks the Single Farm Payment. Also see the Government website:

http://www.netregs.gov.uk/netregs/businesses/agriculture/61893.aspx