Division 1.4 Water consumption and waste water discharge
United Kingdom
BAT 7. In order to reduce water consumption and the volume of waste water discharged, BAT is to use BAT 7a and one or a combination of the techniques b to k given below.
| Technique | Description | Applicability | |
|---|---|---|---|
| Common techniques | |||
| (a) | Water recycling and/or reuse | Recycling and/or reuse of water streams (preceded or not by water treatment), e.g. for cleaning, washing, cooling or for the process itself. | May not be applicable due to hygiene and food safety requirements. |
| (b) | Optimisation of water flow | Use of control devices, e.g. photocells, flow valves, thermostatic valves, to automatically adjust the water flow. | |
| (c) | Optimisation of water nozzles and hoses | Use of correct number and position of nozzles; adjustment of water pressure. | |
| (d) | Segregation of water streams | Water streams that do not need treatment (e.g. uncontaminated cooling water or uncontaminated run-off water) are segregated from waste water that has to undergo treatment, thus enabling uncontaminated water recycling. | The segregation of uncontaminated rainwater may not be applicable in the case of existing waste water collection systems. |
| Techniques related to cleaning operations | |||
| (e) | Dry cleaning | Removal of as much residual material as possible from raw materials and equipment before they are cleaned with liquids, e.g. by using compressed air, vacuum systems or catchpots with a mesh cover. | Generally applicable. |
| (f) | Pigging system for pipes | Use of a system made of launchers, catchers, compressed air equipment, and a projectile (also referred to as a ‘pig’, e.g. made of plastic or ice slurry) to clean out pipes. In-line valves are in place to allow the pig to pass through the pipeline system and to separate the product and the rinsing water. | |
| (g) | High-pressure cleaning | Spraying of water onto the surface to be cleaned at pressures ranging from 15 bar to 150 bar. | May not be applicable due to health and safety requirements. |
| (h) | Optimisation of chemical dosing and water use in cleaning-in-place (CIP) | Optimising the design of CIP and measuring turbidity, conductivity, temperature and/or pH to dose hot water and chemicals in optimised quantities. | Generally applicable. |
| (i) | Low-pressure foam and/or gel cleaning | Use of low-pressure foam and/or gel to clean walls, floors and/or equipment surfaces. | |
| (j) | Optimised design and construction of equipment and process areas | The equipment and process areas are designed and constructed in a way that facilitates cleaning. When optimising the design and construction, hygiene requirements are taken into account. | |
| (k) | Cleaning of equipment as soon as possible | Cleaning is applied as soon as possible after use of equipment to prevent wastes hardening. | |
Further sector-specific techniques to reduce water consumption are given in Section 6.1 of these BAT conclusions.