Análisis sobre las curvas Granulométricas

Principles The options for waste recovery and recycling are covered in Section 2.6 on page 83. Waste

avoidance/minimisation, and the use of clean technologies, is a theme which runs throughout Section 2.1 on page 17 and Section 2.2 on page 41. This section deals with the systematic approach to look for other opportunities.

Waste minimisation can be defined simply as: “a systematic approach to the reduction of waste at source, by understanding and changing processes and activities to prevent and reduce waste”.

A variety of techniques can be classified under the term waste minimisation, from basic housekeeping through statistical measurement, to application of clean technologies.

In the context of waste minimisation and this Guidance, waste relates to the inefficient use of raw materials and other substances at an installation. A consequence of waste minimisation will be the reduction of gaseous, liquid and solid emissions.

Key operational features of waste minimisation will be:

• the ongoing identification and implementation of waste prevention opportunities

• the active participation and commitment of staff at all levels including, for example staff suggestion schemes

• monitoring of materials’ usage and reporting against key performance measures

For the primary inputs to activities which are themselves waste activities, eg. incineration, the

requirements of this section may have been met “upstream” of the installation. However, there may still be arisings that are relevant.

See the Waste minimisation support references for detailed information, guides and case studies on waste minimisation techniques.

Table 2.7: Raw material substitutions

Raw material Selection techniques

Organic solvents Supercritical Fluids: The use of supercritical carbon dioxide, for example, in the caffeine extraction process has eliminated the use of the more conventional hexane solvent

Cleaning and sanitisation mate- rials

(see Section 2.1.16 on page 36)

Chemical agents with rapid degradation and known degradation products should be used.

Assess the types and ranges of cleaning agents; for example, are acid washes required?

Caustic for fruit and vegetable peeling (see Section 2.1.3 on page 21 and Section 2.2.2.1 on page 46)

Only “low-mercury” NaOH should be used.

2.4.2.1 Recycling of auxiliary chemicals

It was stated in Section 2.4.1 on page 72 that a proportion of the chemicals used for cleaning purposes will end up in the final effluent, even if much reduced by treatment. This is not only a loss of a raw material, but means that more effort will be required to treat the effluent.

In addition to measures to ensure the optimal application of cleaning chemicals, techniques are becoming available to recover chemicals from, for example, cleaning-in-place (CIP) systems. Nanofiltration can be used to recover 90% of caustic or acid from spent process solutions (Ref. 5), although not all effluent types are compatible with nanofiltration techniques. This may be suitable for large-scale cleaning processes, for example:

• cleaning of evaporators in the dairy sector • bottle washing in breweries

• general CIP applications

Indicative BAT requirements for waste minimisation audits

Identify the raw and auxiliary materials, other substances and water that they propose to use.

1 The Operator should carry out a waste minimisation audit at least every 4 years. If an audit has not been carried out in the 2 years prior to submission of the application and the details made known at the time of the application, then the first audit shall take place within 2 years of the issue of the Permit. The methodology used and an action plan for reducing the use of raw materials should be submitted to the Regulator within 2 months of completion of the audit. The audit should be carried out as follows:

2 The Operator should analyse the use of raw materials, assess the opportunities for reductions and provide an action plan for improvements using the following three essential steps

• process mapping • materials mass balance • action plan

3 The use and fate of raw materials and other materials, including by-products, solvents and other support materials, such as fuels, catalysts and abatement agents, should be mapped onto a process flow diagram (see the Waste minimisation support references). This should be achieved by using data from the raw materials inventory and other company data as appro- priate. Data should be incorporated for each principal stage of the operation in order to construct a mass balance for the installation.

4 Using this information, opportunities for improved efficiency, changes in process and waste reduction should be generated and assessed. An action plan should then be prepared for implementing improvements to a timescale approved by the Regulator.

Figure 2.1: Cleaning-in-place chemical recovery membrane system

2.4.2.2 Packaging

Packaging includes a number of raw materials, such as corrugated cartons, plastic bags, shrink-wrap, stretch-wrap, layer pads, pallets and slip sheets, drums and other containers and filler materials (polystyrene, foam, paper), etc. IPPC addresses packaging waste associated with the production process. (The requirement to minimise the impact of packaging and packaging waste on the

environment in general is regulated under the Producer Responsibility Obligations (Packaging Waste) Regulations 1997 (as amended) and the Packaging Essential Requirements Regulations 1998 (regulated by local authority Trading Standards Officers).)

Pollution prevention with respect to waste packaging should be addressed using the waste minimisation hierarchy, hence:

• avoiding packaging • reducing packaging • re-using packaging • recycling packaging

The optimum packaging size should be used, which takes account of product size, shape, weight, distribution requirements and packaging material selected (without compromising product protection, preservation and containment). The packaging must achieve fitness of purpose, minimise the amount of packaging material used, maximise the amount of product per pallet and optimise warehouse storage. Often by designing the packaging effectively, waste can be avoided or at least reduced.

Concentrated waste to disposal Forward Feed Pump Return pump Neat Caustic make up Membrane system To drain Caustic Storage Tank Cleaned caustic Process tank for cleaning

A large variety of packaging materials exist within the Food and Drink sector. Packaging materials should be selected that cause the least environmental impact. To keep waste to a minimum, the weight and volume of each material, together with its recycled content, should be considered, as should the potential for re-use, recycling and disposal of the packaging. Often one material can replace the need for another; for example, recyclable shrink-wrap could replace the need for cardboard trays and shrink- wrap.