​A1.1 Discharges to Air

Generally speaking any significant intentional discharges to air of a hazardous substance in amounts of a tonne or more in any one year may require authorisation and SHE Group should be consulted prior to starting any such discharge.

Discharges from fume cupboards within STFC are unlikely to require authorisation but nuisance from odors or smoke should be considered.

However certain substances are covered by specific regulations:

Solvent Emissions Directive/Regulations

The purpose of the Solvent Emissions directive is to control emissions of volatile organic chemicals (VOCs) to the environment. It does not cover trivial emissions from, for instance, cleaning surfaces by wiping with a solvent soaked cloth, but may cover a large degreasing plant using tri-chloroethylene where the total emissions from the plant could be greater than 1 tonne per year.

Where VOC usage on any particular installation is of the order ‘tonnes per year’ then the SHE Group should be consulted to ensure that the installation complies with the Directive and that any authorisation and/or solvent management plan is in place and, as appropriate, the local authority informed.
Note that the Control of Substances Hazardous to Health Regulations may also apply (see STFC SHE Code No 37)

F-Gas & Ozone Depleting Substances​

A number of fluorinated solvents (chlorofluorocarbons – CFCs; hydrofluorocarbons – HFCs) and gases (especially SF6) are carefully controlled due to their effect on the ozone layer. The use of such chemicals for cleaning is banned and their use in self-contained systems, such as refrigerant plant, is strictly controlled.

Installations which use SF6, such as high voltage switchgear, and certain refrigerant gases (e.g. R22), are subject to strict maintenance requirements and can only be maintained by qualified engineers. Such systems should be labelled and a log kept of all maintenance activities (see Appendix 4).

It should also be noted that air-conditioning systems which have a total cooling capacity of greater than 12kWhr are required to comply with the Energy Performance of Buildings (Certificates and Inspections) Regulations.

A1.2 Discharges to Controlled Waters

Any intentional discharge, other than uncontaminated surface water, to a controlled water (for example a river or canal) will require an authorisation.

Abstraction of significant quantities of water from a controlled water course (and subsequent return), for example for cooling purposes, may also require authorisation.

SHE Group should be consulted prior to any such proposed discharge or abstraction.

A1.3 Discharges to foul (trade effluent)

Discharge of waste water/liquid other than domestic sewage and uncontaminated rainwater will require authorisation.

A1.4 Liquid Discharges from Laboratories

It is permitted to dispose of certain chemicals which are not classified as ‘Hazardous Waste’ via a sink connected to a foul drain when washed down with excess water. These chemicals include:

• Mineral acids and alkalis which have been diluted to ensure the pH is between 6 and 10.
• Harmless soluble inorganic salts (including all drying agents such as CaCl2, MgSO4, Na2SO4, P2O5)
• Alcohols containing salts (e.g. from destroying sodium)
• Hypochlorite solutions from destroying cyanids, phosphines, etc.

It is NOT permitted to dispose of chemicals on the UK ‘Red List (PDF - 5kB - link opens in a new window)’ via the drain; they are hazardous waste and should be disposed of appropriately (See STFC SHE Code 31 for disposal procedure).

If the above procedures cannot be guaranteed, then discharges from the laboratory should be to an effluent pit which can be tested for contamination before being batch pumped to foul or emptied as Hazardous​ Waste, if contaminated.

A1.5 Limits on Discharges of liquids

Any authorisation to discharge liquids to either a controlled watercourse or to public sewer will specify limits on certain physical and chemical properties of the discharged liquid:

• pH;
• temperature;
• chemical oxygen demand;
• biological oxygen demand;
• suspended solids;
• heavy metal content;
• nitrate and sulphate content; and
• volume.

A procedure must be put in place to ensure that any discharges are within the limits specified in the authorisation.

Currently STFC sites hold the following authorisations:

• DL – Trade
• RAL – Trade
• ROE – Trade

A1.6 Discharges to Land

The only discharges allowed to land within STFC are those of surface water. No other discharges to land are permitted. It is possible that historical spills to land have occurred and this should be considered when carrying out Environmental Impact Assessments (see Appendix 3), especially where there is an identifiable pathway to an environmentally sensitive receptor (such as a canal or underground aquifer).​