Monitoring Environmental Performance
Sample Waste Audits
Waste minimisation is the process of systematically reducing waste production.
The process covers raw materials consumption, product loss, energy and water
consumption, packaging, effluent production, wasted effort, and all other solid,
liquid and gaseous wastes.
Companies that reduce the amount of waste produced not only reduce waste management
costs, but also save in raw materials costs through reduced resource wastage.
Minimising waste can also help reduce environmental liability and insurance costs,
and yield income from the sale of reusable waste.
A waste survey of B&C Coatings was undertaken on the 26th
October, 1999. The survey was carried out as an initial review using data
collected on site and involved:
- Identifying wastes. A site tour, detailed discussions with
Mr J King proprietor of B&C Coatings, and observations were used to
identify wastes generated by each process/area.
- Gathering basic quantity and cost data. Historical waste and
purchase record data was collated to determine raw materials consumption,
waste quantities and disposal costs. Although information gathered from
historical data did not cover all wastes (i.e. product loss, handling costs,
etc.), it was sufficient to identify opportunities for reducing waste. The
majority of waste routes need to be better defined.
- Identifying opportunities for reducing waste. Using the
available data and our experience of energy and waste management, areas of
the business where there are opportunities to reduce waste were identified.
- Identifying legal obligations. All companies have a duty of
care to ensure that wasted materials are managed correctly. An assessment
of compliance with relevant legislation was also made.
- Targets are needed for a reduction in paint and powder waste. Initially,
we suggest a figure of 2% reduction against a production baseline given in
terms of sales value or monthly turnover. We recognise that the blend of work
has changed significantly over recent months so that new targets need to be
"flexed" against sales value by work category.
- Improved technology is needed to speed up the coating/curing process and
to allow more flexibility in terms of components sizes in the various processes.
There is significant scope for reducing energy cost and improving throughput.
For example, we envisage that for certain finishes the throughput cycle could
be halved in time through adoption of improved handling and drying technology.
- Coating technologies have improved significantly over recent years. B&C
keep abreast of current technologies but are often restricted by customer
specification. A formal waste management, quality control and environmental
management system will assist in giving weight to any requests made by B&C
to use alternative coatings.
It must be noted that due to the jobbing nature of B&C, colour
changes in the process occur regularly (small component batches) so that no
attempt is made to recover powder. Powder coating is an effective but extremely
We have undertaken some crude calculation based on manufacturers figures,
B&C figures and assumed powder coat densities.
Manufacturers of powders typically state that for an 80 micron coat 1 kg
of powder will cover 10 sq. m. of component. This is optimistic since this
relates to the spraying of large flat objects rather than for example,
B&C estimate work based on a figure of 6 sq. m per kilo of sprayed
powder. The component coating has an average density of 0.5.
We estimate wastage as follows:
6 sq m of coat per kg at a thickness of say 80 microns
= 240g adheres to metal
= 760 g to waste
This means that out of the £21500 per annum spent by B&C on
powders, powder to the value of £16,340 is sent as waste. B&C
cost this waste into the work. However, this issue is worthy of further
- Increase the degree to which packaging is returned to the customer.
Disposal of waste packing can be expensive as well as having an adverse
effect on the appearance of the site. Storage of an excess of non-returnable
wooden packing also presents a fire risk close to the building.
- Store all waste records in a central file and ensure that all waste
transfer notes and consignment notes are retained. These should be indexed
and if possible entered into a spreadsheet by waste category.
- Consideration is needed with regards to the disposal of wipes and rags
used for cleaning of work. Organic solvents are used for cleaning since an
effective aqueous alternative has not been found. It was noted that some of
the solvent cleaners in use contain DCM (Dichloromethane) which is extremely
hazardous to personnel and to the environment.
- Disposal of liquid waste proves expensive since there is an unknown
mixture of inorganic pigments and chlorinated/non-chlorinated organic solvents.
Segregation into say three different containers may make waste disposal easier
and less costly. Indeed, paint residues from a single type or source of
product can be distilled for valuable solvent recovery rather than incinerated.
- A large amount of paint and solvent materials are delivered to site in
metal drums (i.e. 25 litres). These containers accumulate at the rear of the
factory in a steel cage. This cage fills until an operative can find time to
crush the drums with a fork lift truck and place them in the skip for disposal.
The company should seriously consider a small can crusher or compactor since
this would save personnel time, increase skip loadings, improve the appearance
of the site and reduce the risk of fire due to a large number of empty containers
being stacked at the rear of the factory.
- The waste routes on site are relatively complex. Powders are not recycled
due to the jobbing nature of the shop. A further investigation is need into
defining waste streams on site. The streams should be shown as flow charts or
on a suitably detailed site plan to allow improvements in routing, handling,
segregation and disposal to be strategically planned.
- In order to reduce wastage of energy for the drying curing processes it
will be necessary to redesign and to an extent replace the ovens used for dying.
- The company has carried out certain modifications to date to prevent the
egress of powder from the site.
- B&C needs to ensure that compressed air generated on site is utilised
effectively. At the present time the valve at the base of the in-line pre-filter
is left partially open to expel condensate form the air line. This is not
acceptable. Firstly, wasting air is expensive since it results in excessive
compressor run/load hours and unproductive electrical energy consumption.
Secondly the condensate contains mineral oil. This cannot be allow to enter
surface water drains and should not be piped onto the ground. This material
must be collected and disposed of in a suitable manner.
There are two main items in need of rectification. A timed solenoid type
condensate blow down valve should be fitted to the filters and other points of
blow-down in the system such as the receiver. This will allow say 10 seconds
of blow-down per hour and will reduce air wastage significantly.
The oil/water emulsion (condensate) must be collected
in a container and sent as special waste or an oil water separator should be
installed. This would allow the water to be piped to the foul drain, the oil
being collected in a suitable, labelled, closed 205 litre containers for
collection as special waste by an approved oil recycler once per annum (or less).
The less air that is wasted the less condensate is produced.
- It is important that liquid waste (solvents/oils/etc.) stored to the rear
of the premises are treated correctly. These liquids should be identified,
sampled and decanted into suitably labelled sealed steel drums. The waste
drums should be placed in a safe, dedicated, labelled, bunded area to the
rear of the site where they can await collection as special waste by an
- Skip usage is small. Three 6 yard lidded special waste skips are utilised
per annum at a cost of £600.00 total.
- The process of burning waste packing on site needs to be reviewed. This
is not generally acceptable. An alternative disposal method should be
- At the present time a large number of empty drums are left open (to minimise
explosion risk). These fill with rain water. This water is then poured onto the
ground or into a surface water drain prior to crushing the container. This
process is not acceptable and could result in severe penalties should a
watercourse become contaminated. Drums should ideally be stored under cover or
crushed straight away and placed in the skip.
- Waste produced by re-work can be reduced. At the present time inclusions
in the finish mean that around 5 to 10% of work requires re-work. This is
expensive and wasteful. Inclusions result form the poor fabric of the building
as well as particulates dislodged from the track due to vibration and operator
error. Other problems such as over-spray, drag etc result from operator error
in the wet finishing process. Issues such as using the wrong colour on a
component are few and far between. Rework could be reduced significantly by the
adoption of a formal work and order processing system employing job cards that
stay with the work through its progression around the site.
- Use of 2 packs is increasing on site. There will be an increase in waste
paint residue due to the process. Approximately 1 litre is required to prime
the paint gun line. A 2 pack is not re-usable since it will cure and cannot
be placed back in the tin, thinned and mixed like a traditional solvent based
1 part paint.
- A great deal of personnel training is required in order to reduce waste.
This ranges from basic awareness (e.g. when on site the hot water tap in the
toilet was left on) to methods of reducing managing and segregating waste.
2. BASIC COST DATA
The company's principal resources, waste outputs, quantities and cost (where available)
are listed below. This data was collated from historical purchase and waste records.
Although different units of measurement make it difficult to determine annual quantities,
the data is useful in highlighting high consumption and cost resources and wastes.
B&C utilise the following materials. A detailed analysis of the quantity of
each material i.e. the solvent content of paints and thinners, is very complex and is not
given. However the principle areas of waste can be associated with the materials utilised
in the processes.
- 2 pack wet products.
- Traditional wet paints/primers/etch primers.
- Thinners (e.g. cellulose) gun wash, degreasers, paint thinners etc.
- Polyester powders.
- Epoxy-polyester powders.
- Pre-treatments for galv components.
- Rags and tack-rags.
- Polymeric and bubble pack packaging and adhesive tapes (PVC).
- Paint strippers.
- White spirit.
Records show that B&C spend annually in the region
|Item ||£ |
|wet paints ||8600 |
|degreaseers ||8601 |
|6 yard skips ||600 |
3. COMPLIANCE WITH WASTE MANAGEMENT LEGISLATION
Part 2 of the Environmental Protection Act 1990 (EPA) defines any waste that comes
from industrial, commercial or domestic sources as being controlled waste. The EPA
established a duty of care on anyone (except householders) who has control of, or
responsibility for, controlled waste at any stage from its production to its disposal.
|Duty of Care requirements:
|Prevent any other person treating,
keeping or disposing of waste other than in accordance with waste management
licensing legislation or in a manner likely to cause pollution of the environment
or harm to human health.
||B&C are aware of waste control
and transfer requirements and use suitable contractors
|Prevent the escape of waste.
||A number of items of waste are not
controlled. Steel scrap, rubbish, waste cans and waste oils are examples.
|Ensure that waste is only
transferred to an authorised waste carrier.
||As far as we can determine the
correct types of contractors are used.
|Complete a transfer note which must
include a written description of the waste and details of where the waste is
transferred to, and be signed and kept by the parties involved for two years
||Some ambiguity surrounds the
'Tom White' skips. This is in need of investigation.
Certain controlled wastes are considered to be potentially hazardous and require
special handling and treatment. The handling of these wastes is controlled by the
Special Waste Regulations 1996 (SWR) as amended, which defines a more stringent system
|Special Waste Regulation
|Special wastes must be controlled
using a five part consignment note system
||Consignment notes are used.
|The removal of special waste must
be pre-notified to the EA at least 72 hours before the waste is going to be removed
||Written conformation is required by
Tom White Waste.
|Completed consignment notes must
be retained for three years.
||Consignment notes are retained on