Yes. There are two aspects to consider, one is complying with building regulations which deal with the day to day use of the toilet within the fabric of the building and the other is the Environment Agency, which is concerned with the manner, method and safety of how the outputs are dealt with.
Current building regulations (as at 2019) permit compost toilets provided that there is a way to empty them without having to carry the compost material through a living area (including a kitchen). Further information on the relevant building regulations is on our website [link].
The Environment Agency in England and Wales (the SEA in Scotland) permit the discharge of urine to the ground (through a leaching bed / soak-away pit) provided you are at least 10 metres away from a water course. Solids can be composted onsite provided that the resulting compost is not used for commercial growing. Further information on composting/dealing with solids and liquids are on our website [link].
Please note that this is our interpretation of the current regulations and is given in good faith but does not represent legal advice. You should always consult the relevant official bodies to ensure you comply with all relevant regulations.
Do you have any further questions? Please get in contact and we’d be happy to answer them for you!