I understand these ...

I understand these definition in a larger sense:

Sanitation means the, let's say, "controlled", i.e. safe, disposal of solid and liquid waste, e.g. black and grey water from the household, but from commercial or industrial sources as well. This includes needed infrastructure and management systems from household to communal to national level.

Hygiene means in the first line personal hygiene, i.e. washing, brushing teeth, safe storage of food items and drinking water. In a larger sense this includes household facilities enabling a good hygiene practice, e.g. toilets, latrines, washing places, safe storage containers etc.

In a still larger sense, environmental hygiene is used to describe infrastructure and management systems dealing with all kinds of waste in settlement areas and the safe disposal of such waste. This reflects on personal behaviour (littering, clean households and concessions), on small-scale public behaviour (clean streets and public places through controlled disposal of liquid and solid waste) to a -generally- communal role in the collection and disposal of waste. It includes needed infrastructure and waste collection and disposal devices.