Operational management tools .1 Overview

While the inventory management tools (see Section 3.1.5.2) provide all the necessary information without which no decisions about effective waste prevention, minimisation and/or treatment are imaginable, the operational management tools provide the basis to put these

3.1.5.3.2 Management of changes involving process and/or plant modifications Description

Changes involving process and/or plant modifications are relatively frequent in the chemical industry sector, e.g. to improve the performance/efficiency of production, to enhance safety or security, to enable the manufacture of new or modified products, to reduce maintenance or operating costs, and to enhance environmental protection. In addition, changes are carried out in order to satisfy market strategies that may involve changes of product grade and/or the reallocation of production and consequently the transfer of processes to other installations/plants. Changes are also conducted in the framework of decommissioning the plant.

Modifications can be classified as minor or major, or as substantial or not, generally based on the following criteria:

 the foreseen impact of the changes on the safety of the installation including both processes and workplace safety issues;

 the likely impact of the changes on the environment (air, water, waste, energy and raw material consumption);

 the extent and complexity of the changes.

According to the IED (2010/75/EU), substantial changes within an IED plant or installation are subject to the granting of prior authorisation by the competent authority [ 5, Directive 2010/75/EU 2010 ].

Plant modifications are designed and implemented with the objective of maintaining the installations in compliance with laws, regulations and standards (both internal and industry standards), to protect the environment and to ensure an appropriate level of reliability and safety of the operation of the plant.

Whole effluent assessment (WEA, see Section 3.2.2.3) is an instrument that is used in some Member States (e.g. Sweden) in the permitting procedure for checking that the implementation of process changes does not harm the environment.

Management procedures concerning plant modifications are in place as part of the EMS to manage plant modifications (see Section 3.1.2, point 'c'). An effective management of changes is generally achieved by the implementation and follow-up of appropriate procedures to verify and control the projected modifications from the very early phase of the investment planning.

Changes involving process and/or plant modifications take into account organisational aspects as well as human factor aspects, especially when the changes are considered major based on the criteria mentioned above.

A sample workflow for the management of changes is given in Figure 3.2.

Additional

SAFETY/ENV. PROTECTION ANALYSIS & EVALUATION

MANAGEMENT OF CHANGES – SAMPLE WORKFLOW

PLANNED MODIFICATION(S), e.g.:

Figure 3.2: Sample workflow for the management of changes

Achieved environmental benefits

An adequate management of changes minimises the environmental impact of carrying out plant modifications.

Cross-media effects

No cross-media effects are believed to be likely.

Operational data

Examples of plant modifications or changes are provided in the following list (the list is not exhaustive):

 the installation/decommissioning of machinery/equipment (e.g. pump, heat exchanger, filter, valve, instrumentation, storage tank, vessel);

 the modification of connections between plants/processes/systems/components;

 the modification of set-up parameters of the process safety control equipment (e.g. set-up pressure of safety valves, rupture disks, pressure, temperature and level metering devices);

 the modification of logical loops (mode of intervention of instrumentation);

 the substitution of machinery/equipment for different alternatives;

 the repair of machinery/equipment whenever the intervention leads to relevant modifications of the characteristics and/or performances (e.g. repair of a stirrer with modification of typology, repair of a pump leading to significantly different performance characteristics).

Examples of changes which are not generally considered to be relevant modifications are listed below:

 the substitution of machinery/equipment for identical ones or those with the same characteristics;

 the repair of machinery/equipment keeping the same performance characteristics;

 the interventions of ordinary, extraordinary, programmed and preventive maintenance without modification of the original characteristics of the machinery/equipment being maintained.

Applicability

The management of changes is applicable at all installations. The extent to which management procedures to deal with plant modifications are developed depend for the most part on the size and nature of the operation (i.e. procedures in place at large Seveso plants are expected to be more developed than those in place at small non-Seveso installations).

Economics

No relevant extra costs are expected. Costs savings are expected.

Driving force for implementation

The drivers for implementation include minimising the environmental impact and complying with legislation.

Example plants

Several IED installations, in particular Seveso plants.

Reference literature

[ 5, Directive 2010/75/EU 2010 ] [ 156, Grandi 2008 ]

3.1.5.3.3 Setting and regular review of internal targets or programmes Description

An EMS (see Section 3.1.2) needs to establish an environmental programme where global, long-term and internal, site-specific targets are set. The global and long-long-term targets are part of company policy and thus not included in this BREF, but it is stated that such a policy is a necessary item.

The parameters for which internal targets are set should be selected according to their relevance.

In order to limit the number of these parameters, the purpose of the target setting should be kept in mind, i.e. the optimum running of production and abatement operations should be ensured, thereby minimising the impact on the environment as a whole. It is usually not necessary to set target levels for each and every parameter involved, but to use surrogate parameters to describe the emissions. The measurable target levels need to be set in such a way that the permit level of the final outfall as well as the specific local conditions can be readily met.

The dynamic process of target setting, given that the chemical industry and the conditions in which it operates are subject to continuous development and constant change, implies a regular review, regardless of whether new legal requirements have been introduced. Thus, a programme to meet these changes needs to be set up. The goal of this regular review is the continuous improvement of the environmental performance of a chemical industry site as a whole. To achieve this permanent goal, a reduction programme should be established that contains the following elements:

 a periodic evaluation of environmental management practices associated with operations and equipment, taking into account:

◦ environmental impacts,

◦ changing legislation,

◦ public concerns,

◦ implementation of ongoing improvements;

 incentives for the implementation of cost-effective actions and recognition for significant contributions to emission reduction targets, such as:

◦ cost allocation of waste water and waste gas treatment by introducing a pricing system, e.g. the introduction of an internal 'polluter pays principle (PPP)', for discharge from the individual production units, which are charged internally with the costs of the treatment facilities according to their share of pollutant input; this is a good incentive to minimise emissions and thereby reduce the shared treatment costs of the production unit;

◦ internal awards (bonus payment) for operational improvement proposals by staff;

◦ internal competition for reducing process disturbances and accidents;

 inclusion of objectives for release prevention in the design of new or modified facilities and processes, such as:

◦ introduction of recycling of starting compounds or products, when modifications of the installation are planned;

◦ introduction of water conservation measures, under the same conditions as above;

 preventive maintenance and appropriate control technology to minimise emissions and losses;

 implementation of engineering and operating controls and procedures, with operating criteria, to improve prevention, early detection and containment of spills/releases either by:

◦ monitoring surveillance, or

◦ organisational measures, using personnel power, such as regular control rounds, or installing containment systems with sufficient collecting volume;

 investigation and evaluation of spills/releases that have occurred, to identify corrective actions to prevent a recurrence;

 communication with employees and members of the public regarding information on emissions, the progress in achieving reductions and future plans, which should include a structured dialogue on the concerns and ideas of both employees and members of the public.

This review may lead to decisions to modify or even adapt the environmental objectives, programme or policy.

Achieved environmental benefits

The technique is expected to help plant management react more effectively and more quickly to environmental challenges and therefore to minimise the impact of the functioning of the installation on the environment as a whole.

Operational data

There are several classes of targets, one class given as general standards, another as site-specific standards. Examples of general standards are:

 the requirements of environmental quality objectives or environmental quality standards as well as technology standards and 'good manufacturing practice';

 the general requirements for river basin quality (Water Framework Directive [ 28, Directive 2000/60/EC 2000 ] or national regulations on water quality);

 the general requirements for emissions to air, international or national programmes;

 requirements of internal company standards issued for all sites, independent of local permit demands.

Examples of site-specific standards are:

 requirements of permit conditions (e.g. ensuring continuous compliance with emission limit values);

 specific limitations on the ecotoxic content of any final outfall in accordance with the limits set for the receiving medium (surface water, air), e.g. in Germany, the achievable values for final discharge into a water body are:

◦ fish test: LID = 2;

◦ daphnia test: LID = 4;

◦ algae test LID = 8;

◦ luminescent bacteria test: LID = 16;

◦ mutagenicity: LID = 1.5.

The toxicity is expressed as 'dilution factors'. LID= 2 means that the waste water stream has to be diluted to half of its original concentration so that no toxic effects can be observed. See also Section 3.2.2.2.

As a long-term target for the future, the German chemical industry (according to the VCI declaration of May 2000 [ 93, VCI 2000 ]) aims to further reduce the toxic impact of its waste water discharge, taking into consideration:

 acute toxicity to fish, daphnia and bacteria;

 chronic toxicity to algae;

 mutagenicity.

They finally seek to ensure that their effluents into receiving water bodies do not exceed dilution factors of LID = 2 (for mutagenicity: LID = 1.5); toxicities caused by salt concentrations are not included.

When targets are being set, a plan should also be drawn up for actions to be taken when a target level of one or more tributary streams, or of the final outfall, is exceeded for a certain amount of time. These actions have to be clearly defined and the responsibilities and competence for these actions have to be assigned.

Examples of internal targets are:

 continuous reduction of pollution loads;

 compliance with permit requirements;

 reduction of ecotoxic effects (see Section 3.2.2.2).

Applicability

The technique is generally applicable to new and existing installations.

Economics

No information provided.

Driving force for implementation

Improving the environmental management system is the main driving force for the implementation of the technique.

Example plants

No information provided.

Reference literature

[ 28, Directive 2000/60/EC 2000 ] [ 93, VCI 2000 ]

3.1.5.3.4 Selection of treatment options

3.1.5.3.4.1 Overview

With the necessary information concerning emissions arising on a chemical site and the environmental targets and demands defined, the next step is the selection of appropriate treatment options. Usually the goal is to find a cost-effective treatment method offering an optimum environmental performance. An appropriate choice normally requires treatability and/or pilot studies.

Available control options are generally evaluated and selected according to:

 the characteristics of the emitted stream, e.g.:

◦ flow rate,

◦ concentration and properties of contaminants,

◦ presence of impurities (e.g. vapour, oil),

◦ temperature,

◦ pressure;

 the load of the streams that need treatment;

 the targets to be achieved, pollutant recovery being the first choice;

 legal requirements;

 the control options that exist for a given case.

This evaluation and selection process – the necessary data obtained by stream inventory/register (see Section 3.1.5.2.3) – always results in the need for additional site-specific conclusions to be taken into account, the key factors varying from site to site, by e.g.:

 plant location;

 size and layout of the site;

 current environmental and economic performance of the installations in question, their age, design and anticipated lifetime;

 potential and degree of process integration within an installation and between installations;

 type and quality of the receiving medium;

 impact on the environment as a result of an actual or foreseen emission;

 remaining lifetime and performance of existing pollution abatement equipment;

 availability of resources;

 safety;

 limitations and constraints on an installation imposed by other legislation;

 results of cross-media analyses (water consumption, waste generation, energy

When central treatment facilities are involved, source reduction options should be considered.

As a result of the considerations mentioned above, the appropriate treatment system will be selected by considering the options for:

 source reduction;

 collection (drainage) system;

 treatment methods.

Special issues for waste water and waste gas are dealt with in Sections 3.1.5.3.4.2 and 3.1.5.3.4.3 respectively.

3.1.5.3.4.2 Selection of waste water control system

Figure 3.3 illustrates a decision path for finding the appropriate waste water treatment system for the individual waste water streams.

The following questions, which contain the main objectives of the IED (2010/75/EU) – prevention, minimisation and control of pollution – should be addressed for each type of waste water:

 Can the amount and contamination level be reduced or eliminated by process-integrated or other means?

 Does the waste water stream as a whole require treatment, or would a segregation system be useful?

 Is the waste water stream suitable for biological treatment, or should it be subjected to decentralised pretreatment?

Production process

Waste water?

Minimisa-tion or avoidance?

Biologically non-degradable?

Containing POPs?

Organic contami-nants?

Conta-minated?

Specific treatment

Pretreatment

Central or municipal WWTP

YES

YES YES NO YES

NO NO

NO

YES

NO

RECIPIENT WATER

NB: Dotted lines symbolise alternative options.

Source: [ 251, Ullmann's 2000 ]

Figure 3.3: Decision diagram for selecting an appropriate waste water treatment system

As an example criterion for prioritising a more thorough examination of tributary waste water streams, the presence of a refractory TOC load in the order of 20–50 kg/d has been used in parts of Germany. Other relevant parameters in this context are heavy metals, halogenated organic compounds, priority substances and toxicity.

The selection procedure follows the steps mentioned in Section 3.1.5.3.4:

Source reduction

The options for waste water reduction at the source should be considered first. In many instances, these will result from process considerations described in the other chemical BREFs.

Suggestions for frequently occurring causes of contamination are described below, categorised into subheadings.

Process water usage depends on the manufacturing process. Its contaminant concentration depends mainly on the solubility of the process stream in water. The following measures should be taken into account:

 process water should be segregated from rainwater and other water effluent, to allow reuse or recycling, as well as to minimise the amount of waste water which requires treatment, the installation of a roof over certain process areas, loading and unloading bays, etc.;

 process water should be used in a recycle mode, whenever it is economically feasible, with a maximum number of recycles before discharge;

 direct contact cooling systems should be avoided whenever feasible;

 a critical review of the need for water scrubbing systems or, when they are used, an investigation into the potential for water regeneration and reuse (see Section 3.3.1) should be carried out;

 water flow for water flushing and sealing systems, which are frequently needed for safety reasons but should not be allowed to flow without control or restriction, should be minimised;

 free oil should be removed to a slop oil system before its discharge to the sewer;

 an effective water/hydrocarbon separation should be carried out as far as practicable in the process equipment before discharging the water to the sewer;

 if feasible, a process fluid should be used instead of steam in Venturi jet devices, or a liquid ring pump should be used, preferably using a process fluid as seal liquid (see Section 3.3.1.7), or a dry vacuum pump should be used, to minimise the contamination generated by vacuum devices;

 as far as possible, the discharge from safety valves, thermal relief valves, bleeds from double block isolation or twin seal valves should be captured, because it is not recommendable to discharge them to areas where clean rainwater is collected;

 laboratory effluent should be collected to a slop tank.

Unintended operational releases to the sewer can generally be avoided through enhanced operator attention. Additional instrumentation or slop collection will often be helpful to enable operators to perform their task efficiently. Also, slop collection facilities are recommended wherever hydrocarbon liquid releases frequently occur. To reduce unintended operational releases, the following measures should be taken into account:

 vents and drains should be plugged or capped whenever they are not in use;

 flush collection should be allowed in a slop system rather than sending it to the sewer, preferably using closed loop sample systems or sampling valves that require no flushing (e.g. ram-type sampling valves), the sample bottles sized in such a way that overfilling is avoided and the sampling frequency and sample kept to the minimum required;

 overfilling of vessels or tanks should be avoided by installation of an adequate level of instrumentation or adequate procedures;

 the use of hoses should be minimised;

 facilities to collect hose drips should be considered;

 roofs over loading racks should be considered;

 kerbs should be installed to ensure containment of spills;

 adequate instrumentation should be considered to protect against overfilling of road tankers;

 product loss should be avoided during water draw-off from tank bottoms;

 the installation of reliable interface detection instruments (i.e. to determine the position of a liquid/liquid or liquid/vapour interface in a remote inaccessible location) should be considered;

 the pigging of lines should be considered instead of flushing and draining, whenever applicable;

 spills should be vacuum cleaned whenever possible rather than hydrojetting or steaming

Conservation of water by process-integrated and other measures, however, leads to more highly concentrated water streams that might be profitably recycled or exploited for higher production yields or be treated with greater efficiency. So, any means to reduce water consumption might directly lead to a reduction in the quantity of contaminants evacuated through the sewer.

Turnaround and other maintenance activities often result in significant water contamination. To minimise this requires careful planning well in advance, and includes:

 defining a dedicated equipment cleaning site, equipped with adequate facilities to recover hydrocarbons and solid waste, making this the obligatory location for equipment cleaning as far as possible (e.g. exchanger bundle cleaning);

 carefully planning the draining of equipment to avoid undesirable releases to the sewer;

 carefully evaluating the equipment cleaning needs and methods;

 defining a disposal route for all cleaning effluent.

Releases resulting from equipment failure are, by nature, unpredictable. Preventive maintenance for equipment and implementation of a monitoring programme are ways to ensure that these are minimised, for example:

 avoiding as far as possible pump seal failure;

 considering the installation of seal-less pumps, vibration monitoring or leak alarms on seals;

 detecting leaks to cooling water resulting from exchanger failure by periodically checking the hydrocarbon content, pH and electrical conductivity of the cooling water return;

 repairing detected leaks as soon as possible;

 analysing frequently leaking systems to define the most suitable type of equipment, packing, gasket, etc.

Background contamination from foul sewer systems can be minimised by, for example:

 periodically checking sewer inspection chambers for the presence of free hydrocarbons, etc., and vacuum pumping them, if needed, to the slop;

 periodically checking sewer inspection chambers for the presence of free hydrocarbons, etc., and vacuum pumping them, if needed, to the slop;

In document Best Available Techniques (BAT) Reference Document for Common Waste Water and Waste Gas Treatment/Management Systems in the Chemical Sector. Industrial Emissions Directive 2010/75/EU (Integrated Pollution Prevention and Control) (Page 139-160)