The water cycle
Water moves in a cycle from the atmosphere, where it condenses as a vapour, via precipitation to the earth. As it runs downhill in streams and rivers out to sea, it is also evaporating, releasing water vapour back into the atmosphere. Considered as a whole, the world is not running out of water, but in many areas there is either too much or too little water. Also, in many parts of the world, human beings do not have ready access to clean, disease free water for their daily needs.
Using water
All businesses use water, even if it is only for drinking water, mess facilities or toilets. Many businesses also need to use water as part of their processes, whether as part of a product, as a solvent or cleaning agent. Most will use water to clean the premises from time to time, and many may undertake activities such as the cleaning of vehicles in their yard or car park.
All these activities involve the consumption of clean water and the disposal to the environment of contaminated water.
Abstraction of water
Many businesses take water directly from the environment. Some companies rely on their own boreholes from which they abstract water from aquifers (accessible bodies of underground water). Others remove water from rivers for use either as process cooling water for machinery or sometimes it is held in ponds or ‘impoundments’ to be used in sprinkler systems in the event of a fire.
All of these abstractions can only be made legitimately with the correct consent from the Environment Agency. River water and groundwater are classed as ‘controlled water’ under the Water Resources Act 1991 (see emissions to water).
Discharges from sites
Companies occupying premises built after approximately 1936 will probably have two separate sets of pipes taking water from their site:
Surface water
Rainwater running off the roofs and yard areas will flow through pipes just below ground level which connect either to a nearby body of water such as a stream, river or canal, or to a ‘soakaway’, i.e. a porous hole in the ground which allows the accumulated rainwater to drain slowly away and merge with the groundwater.
For many companies, this water flows through their premises and enters the environment with only the slightest chance of contamination. However, many businesses (for example, companies which allow vehicles to be washed in the office car park) may be allowing heavily contaminated rainwater to enter local watercourses through the surface water drainage system.
Companies where this kind of risk is possible will need a ‘consent’ (the legal term for the relevant written permission) from the Environment Agency to discharge to the surface water drains. The company pays for its consent. The payment covers the costs of the agency, which will inspect the company’s outfall and take samples to ensure compliance.
Foul water
The other main connection will be to the sewerage system. Water which is used to flush away waste materials from toilets, kitchens, sinks, and in many cases, process equipment, laboratories, etc. goes into the sewerage system where it is purified before eventual discharge to the environment.
Legally this waste stream is covered by the Water Industry Act 1991 (see emissions to water). The discharge is regulated as a commercial transaction between the company and the ‘sewerage undertaker’ (usually the privatised water company covering the area).
All the water discharged via the sewerage system has to be paid for. The water from toilets, mess rooms, etc. is usually paid for on a per capita basis. Typically, the water company requires an annual statement from the customer giving details of the number of people on the site.
Waste water from industrial processes is often paid for using a formula based on the level of contamination and the cost of cleaning up the water to a standard acceptable for discharge to the environment (see Mogden formula below).
Mogden formula
The Mogden formula is a way of calculating the charges levied by sewerage undertakers for trade effluent. In effect, the price paid per unit volume is based on how polluted the water is and how much effort it takes to get it to the sewage works and clean it up so it can be returned to the environment. The sewerage undertakers generally take samples from their customers’ outfalls on a regular basis and base their Mogden calculations on the contents of the samples.
Details of the formula as applied by the sewerage undertakers can be found on the website of the water regulator, OFWAT.
The sewerage provider will place conditions on the quality of water its customer is allowed to discharge. The sewerage provider will typically carry out regular tests at the discharge point to ensure conformity. If the water is too heavily contaminated or if it contains materials which are not allowed for in its consent, then the sewerage provider can reject the water.
Saving water
Water as a resource is in one sense renewable since it can be replaced. The problem is that businesses use up supplies of clean water and produce quantities of contaminated water. The business pays twice for most of the water it uses: for the water which is piped in and used, and then the waste water which is piped out. Saving water wherever possible is, therefore, a matter of good economic sense as well as good environmental practice.