Water – endless recycling
Water is an essential and valuable resource. It makes good business sense to manage it like other resources, and to minimise waste. Consider its variety of uses:
- Personal or ‘domestic’ uses:
- drinking;
- food preparation;
- personal hygiene; and
- toilet flushing.
- Process uses:
- washing and rinsing;
- as a solvent;
- chemical processing;
- transport system for waste (to sewer or surface water);
- heat circulation medium (e.g. in radiators); and
- heat dissipation medium (e.g. in cooling towers).
Separation of drainage systems
If the site your company occupies is a particularly old building (built before around 1936), you will find that all the water leaving your site (including rainwater from roofs and yards, waste from toilets, kitchens and mess rooms, and process water) will exit via one set of pipes. These will connect to the sewerage system.
Newer buildings are served by two separate sets of waste water pipework. The ‘foul’ water from toilets, sinks and most kinds of industrial process goes out to the sewerage system.
The lightly contaminated rainwater from roofs and yards (surface water) will travel through ‘storm water’ drains laid a little below ground level, which connect to a nearby stream or river. In some circumstances, storm water enters a ‘soakaway’ – an underground chamber with a porous structure which allows water to seep slowly away into the ground. The ‘receiving waters’ – streams, rivers, groundwater, etc. are all legally classed as ‘controlled waters’ and regulated by the Environment Agency.
The various pathways water can take when flowing through an industrial site can be summarised in the following diagram:
Routes for water discharge from a site
Sewerage system
The term sewerage system covers the entire infrastructure used to collect and process foul water before returning it to the natural water cycle. This includes foul water sewers, associated valves, pumps, screens, tanks and the sewage treatment works themselves.
The sewerage systems throughout England and Wales are run by commercial companies operating as ‘sewerage undertakers’ (see WIA Part IV on page 20 of EEF Register of Environmental Legislation).
Water in the natural environment
Whatever happens to water whilst it is under control on a site, it will eventually return to the ‘natural’ part of the water cycle. When it does so it will carry with it any pollutants which have either been deliberately introduced or not removed.
Most of the water in the natural environment in England and Wales is legally under the control of the Environment Agency. The exceptions are small and insignificant bodies of water which do not connect to the wider environment, e.g. isolated ditches, garden ponds (see Nuisance below).
The main categories of controlled waters are:
- rivers and streams;
- canals;
- relevant lakes and ponds, and certain reservoirs;
- estuaries and coastal waters; and
- ground waters.
Note that ‘groundwater’ (i.e. any bodies of water underground, which would include water-saturated clays and rock strata) is included in the category of controlled water (see Water Resources Act 1991 Part III on page 19 of EEF Register of Environmental Legislation).