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Guidelines on remediation of contaminated sites

8. Design

8.1 General conditions

This chapter deals with the situation where remedial measures are to be carried out. The Danish EPA has published a ‘Project Management Handbook for Soil and Groundwater Contamination’ (1995) /27/ (Projektstyringshåndbog for jord- og grundvandsforureninger), to which this chapter refers.

For decision-making, it is important that an organisation chart and clear divisions of responsibility are established prior to initiating a remediation project. Areas of responsibility and authority for specialist work, deadlines, and costs, should be made clear in the organisation of the project.

In addition to the Environmental Protection Act and the Act on Waste Deposits, a number of rules and guidelines will be used in remedial projects, for example sections from the Health and Safety at Work Act, building regulations, rules for plant and technical installations, instructions, etc. The most important rules appear in the ‘Project Management Handbook’ /27/.

Permits should be obtained from local authorities and counties. Amongst other things, permits are required from counties for:

	Discharge into the rainwater system and recipients
	Abstraction of groundwater (for pump-and-treat purposes)
	Establishing treatment plants
	Establishing landfills
	Constructing fences (non-urban zones)

Permits are required from local authorities for:

	Emissions into the air (Chapter 5 enterprises)
	Discharge to sewers
	Excavation work
	Demolition of buildings
	Disconnecting sewers
	Constructing fences (urban zones)

The local authority must also assign landfills / treatment facilities for waste and contaminated soil.

If a change in land use or a new construction is to take place on a contaminated site, there may be a benefit in combining the remedial project with the building project. In these cases, construction should be adapted to the contamination, so that it causes the least possible nuisance; for example for the new use (indoor air, outdoor area) and the work environment during construction work. Construction should be located such that it is possible to carry out remedial measures on any remaining contamination at a later date.

When risk analyses lead to implementation of remedial measures, the investigation phase should conclude with a ‘standardised’ project plan including preparation of an outline project, a detailed project, and subsequently, tender documents for the contractor. The relationship between sub elements in the various projects appears in Table 8.1.

Table 8.1
Relationship between outline project, detailed project, and tender documents for contractors.

*) In tender documents this is often referred to as ‘description of work’ or ‘special description of work’ (SAB) and ‘drawings’.
**) TAG is an abbreviation for tender and payment terms (tilbud og afregningsgrundlag).
***) TBL is an abbreviation for tender lists (tilbudsliste),
****) AB92 is an abbreviation of standard terms issued in 1992 (Almindelige betingelser udgivet i 1992)

In some cases it can be appropriate to conduct investigations and remedial measures using an approach based on normal building and construction projects /2/.

The EU has laid down rules for purchasing goods and services, and performance of construction work through EU tenders. The following threshold values apply in determining whether the product/service shall be put out to EU tender (in 1997 prices):

*) SDR : Special Drawing Rights
a) In addition to these values, certain exemptions and supplements apply /55/.

Furthermore, it is necessary to note that there are a number of time limits for EU tenders.

8.2 The Outline Project

The outline project comprises preparation of one or several alternative projects which fulfil the remediation requirements. The following contents may be used for preparing the outline project:

1. Introduction
2. Background for the remediation project
3. Objectives, including extent of contamination and risk
4. Remedial measures
5. Operation and evaluation phase
6. Timetable and costs
7. Recommendations

The introduction should contain the following information about the site:

	Address, parcel register number, and contaminated site number, if any (location of site should be shown on a map)
	Site owner
	References to relevant investigation reports
	Party who ordered the work (client)
	Consultant

The background for implementing the remedial measures should be described on the basis of an historical review of the site and any previous investigations. Information about land use, groundwater interests and/or objectives for recipient quality, extent of contamination, and risk assessments etc. are relevant here.

The objective of implementing remedial measures and the requirements to be fulfilled by the remedial measures should be described under the objectives section.

One or more proposals for remedial measures which fulfil the above requirements should be given. For each proposal, a brief description should be given of:

	Criteria for the choice of technique
	Project description
	Tests necessary for design of the project
	Overview of the necessary permits, approvals etc. from the authorities
	Assessment of the environmental impact of the proposed measures
	Working-environment assessments of the proposed measures, taking account of the type of contamination

When considering alternative proposals for remedial measures, the costs, quality (environmental effect), and environmental impact (green accounting) of the individual proposals will comprise sub-elements. Comparative financial effect calculations may be included with a view to ensuring the greatest possible environmental and health results from the funds invested. Assessment of alternative remedial measures may be based on construction costs, operating costs, speed and effect of remediation, as well as secondary, derived environmental effects. In this way the best results are achieved for the funds invested. This assumes that the proposed remedial measures all remove the risks demonstrated.

A brief description of the operation and evaluation phase should be given for each solution proposal, including descriptions of any monitoring programmes.

A timetable for remedial measures should be provided, as well as a timetable for a subsequent operation and evaluation phase.

A cost estimate of total expenditures for the remediation project should be prepared. The estimate should include construction expenses as well as operating and evaluation expenses. Furthermore, the cost of preparation of the detailed project, tender documents, supervision, and reporting management for the remedial measures should be estimated. A standard statement of the various items should be prepared in outline and in detail so that costs can more easily be followed throughout the course of the project.

On the basis of the alternative proposals, recommendations should be given for the most appropriate remedial measures at the site.

8.3 The detailed project

The objective of the detailed project is to prepare a detailed description of the execution of the remedial measures. The detailed project should include a detailed technical description, a detailed timetable, a detailed cost overview, and a description of the operation and evaluation phase. Parts of the tender documents which are used in the tendering phase will also be included in the detailed project.

After the remedial project is selected during the preparation of the outline project, it is sometimes necessary to carry out supplemental investigations during detailed planning. These investigations are carried out in order to optimise and design the remediation. Examples include investigations of foundation conditions and detailed mapping of contamination. If in-situ remediation has been chosen, it will usually be appropriate to conduct in-situ tests, e.g. pump tests.

The introduction of the detailed project often includes information about the organisation of the project, location, etc., which is also part of the ‘Special Terms’ in the tender documents (see Section 8.4.2, and Appendix 8.1).

The technical description comprises a detailed description of what is to be carried out. It is often beneficial to prepare this description as a ‘Description of Work’, which is included in the tender documents, prepared prior to carrying out the project (see Section 8.4.2, and Appendix 8.1).

A detailed timetable for carrying out the remedial project should be prepared, as well as a timetable for a possible subsequent operation and evaluation phase.

Costs associated with the project should be broken down into expenditure on consultants, contractors, soil treatment/disposal, water treatment, analyses for documentation, working-environment measures, insurance, unforeseen expenses, operation and evaluation phase expenditure, etc. Individual items should be comparable with items in the outline project.

8.4 Invitations to tender and tender documents

8.4.1 Tender and contracting

A maximum of two tenders should be obtained for closed tenders.

If more than one closed tender is received, the following rules apply:

	If the tender is cancelled, a period of three months after the cancellation must expire before invitations for closed tenders for the same work or order can be made. However, invitations for open tenders may be held immediately.
	If a closed tender is not cancelled, a period of six months from receipt of the most recent closed tender must expire before an invitation for closed tenders may be held for the same work or order, and a new invitation for open tenders may not be held.

For invitations for open tenders, tenders are normally obtained from at least three bidders. If offers are obtained, the following rules apply:

	If the tender is cancelled, a period of three months after the cancellation must expire before invitations for closed tenders for the same work or order can be made. However, invitations for open tenders may be held immediately.
	If the tender is not cancelled, a period of six months from receipt of the tender must expire before invitations for closed tender may be held for the same work or order, and a new invitation for open tenders may not be held.

Cancellation must be reported in writing to each tenderer. See also the Invitations to Tender Act /28/.

Consultants may be chosen as a result of open or closed tenders. In this case, standard contracts between the client and the consultant are prepared. An example of such a contract is included in the Project on Soil and Groundwater from the Danish EPA No. 5, 1995 /27/.

In principle, there are three types of contracts in building and construction projects:

	Specialist contracts
	Main contracts
	Turnkey contracts

Specialist contracts correspond to the client entering into contracts with different contractors according to the division of specialist tasks. Contracts are therefore entered into with specialist firms with differing expertise. Use of this kind of contract requires careful organisation and management from the client or the consultant, as the different parts must operate both individually and together.

In main contracts, the developer enters into a contract with one contractor. After this, the contractor manages the contract which often involves sub-contractors. The developer only has an agreement with the main contractor which is then responsible for services and deadlines.

Turnkey contracts apply when the main contractor is responsible for implementation as well as planning/design of the work. This type of contract is rarely used for remediation projects.

8.4.2 Tender documents

Tender documents should contain a detailed description of the remediation project. An outline for the tender documents is given below:

	Letter of tender
	Contractor summary
	Standard terms
	Special terms (SB)
	Description of work
	Special description of work
	Tender and payment terms (TAG)
	Tender lists (TBL)
	Drawings
	Appendices

The individual parts of the tender material are described in more detail in Appendix 8.1.

The tenders received should be assessed the technical solution and for costs. Sometimes, decisions are based on an evaluation model where both costs and the technical proposal are assigned a specific weight. For example, an equal weighting may be assigned between the proposal and the costs. After choosing the project, the contract with the contractor should be prepared. An example of a contract is included in the ‘Handbook for Project Management of Soil and Groundwater Contamination’ /27/.

If the tender is to include a project proposal, the letter of tender should state that the project proposal will be included in evaluation of the tender, and that the client retains the right to accept the best project proposal, irrespective of the price.

8.5 Supervision

All remedial measures for contaminated soil or groundwater should take place under environmental and specialist supervision. The objective of supervision is primarily to ensure that remedial measures are implemented as described in the detailed project, and that remedial solutions operate in the best possible manner. Therefore, environmental supervision should be conducted with regard to the environmental effect of the remedial measures, and specialist supervision should examine the services provided by the contractor. The following tasks are usually performed as part of supervision:

	Ensure compliance with quality criteria (e.g. in field measurements and analyses)
	Ensure compliance with procedures for the working environment (e.g. in working-environment measurements)
	Contact with the authorities
	Concluding documentation for work completed (reports to the authorities)

It can often be beneficial to describe environmental supervision tasks in an action plan. Experience shows, for example, that excavation projects sometimes reveal contaminated areas which were not identified in previous investigations. Environmental supervision must ensure that such situations are handled according to the specifications in the detailed project.

A supervision report should be prepared as part of the supervision which documents that the quality standards for the project have been complied with. The report should contain a description of the performance of the remedial project. For example, for soil excavation, the report may contain descriptions of where soil has been excavated, the amount of soil which has been excavated, and the fate of the excavated soil. The report should also contain a properly scaled plan with the location of the samples collected for documentation purposes, excavation contours and analysis results, as well as documentation of the location and concentration of possible residual contamination.

Deviations from the original project should also appear. A more detailed description of supervision tasks appears in the ‘Handbook for Project Management’ /27/.

8.6 The work environment and the external environment

8.6.1 The work environment

In construction work on remedial measures, both client and the contractor are liable under the Health and Safety at Work Act. The client should prepare the necessary requirements for the contractor based on the Health and Safety at Work Act and experience. The proposal should be discussed with the Working Environment Authority, so that any problems or uncertainties can be resolved before work commences. It should be noted that the Working Environment Authority does not issue formal approval of work environment measures. The client and the supervision carried out by the client are responsible for ensuring compliance with the Health and Safety at Work Act. Written instructions for the supervisors on work environment measures should be prepared.

The contractor should be informed of the type, concentration, and extent of the contamination, as determined by investigations already completed. The tender documents should therefore include summaries of the results of previous investigations. In addition, there should be information on the requirements for work environment measures, such as choice of appropriate respiratory and other protective devices, personal hygiene, temporary site buildings and facilities, special conditions regarding movement to and from the work site (wash places, sluice systems etc.), technical measures such as use of pressurised cabs on excavators, rules for handling, transport, and disposal of contaminated soil. The Occupational Health Service for construction workers (BST) can also provide advice to the contractor before measures are implemented.

Prior to commencement of work, a plan for health and safety at the construction site is prepared /29/. The plan should be regularly updated and it should be accessible to employees and employers at the workplace throughout the construction period. Usually, the contractor conducting the construction work at the site is responsible for preparation of the health and safety plan. If two or more employers employ more than 10 people at the site at the same time, client is responsible for preparing and updating the plan. The plan should be discussed at a start-up meeting between the supervisors, contractor, Working Environment Authority, and the client.

A notification of the construction site must be made to the Working Environment Authority if the duration of work is expected to exceed 30 working days, and at least 20 workers are employed at the same time, or if the total work is expected to exceed 500 man days. The notification site should be made by the client. It is recommended that the Working Environment Authority is always notified of work on contaminated soil.

References to the Health and Safety at Work Act, statutory orders, and guidelines are in /27/.

8.6.2 The external environment

Planning should also include rules concerning the environment outside of the site. The following problems may arise, with suggested mitigating measures:

	Dust problems from soil work (dust measurements and spraying with water).
	Noise problems (noise measurements and restrictions to specific times)
	Odour problems (odour assessments, and covers or ventilation using air treatment filters.

Close contact with landowners and any residents is crucial to ensuring that a project progresses smoothly. This contact may include delivering reports, holding meetings before the project is put out to tender (gives the possibility for changes), agreements concerning restoration, information to neighbours (possibly via residents meetings), possible meetings during the project (for larger projects), and joint reviews after restoration.

8.7 Project and quality control

In order to ensure optimal control of remedial projects with regard to quality, time, and costs, it is appropriate to include project management, quality assurance, and environmental management.

Aids to project management include descriptions of activities, divided into sub-activities, organisation charts with descriptions of qualifications and tasks, timetables, progress control, budgetary controls, and distribution of documents.

Quality assurance should be carried out and include planning of controls, the actual control, and documentation of controls. The scope of quality assurance depends on the size of the project, but a QA plan should be prepared which, as a minimum, contains the sub-activities which are to be controlled, and the persons who are to perform such controls (should not be the same persons who perform the activities).

Quality assurance will also usually include document management and control, and project scrutiny.

The environmental management system is a relatively new tool which has won recognition as a control tool in remedial projects to ensure environmentally-correct execution and minimal environmental impact. The control elements in environmental management include the project’s energy resources (consumption of energy, transport, and choice of machinery), consumption of water resources, lay out and operation of the building site, health effects for the manufacturers, users and neighbours, global, regional and local health effects, as well as technological-development considerations. The size of the project will influence the need for environmental management.

8.8 Completion of project

At the completion of work, handing over takes place according to AB92, paragraphs 28 and 29 /30/.

According to AB92, paragraph 37, the main contractor has a duty and right to assist in correcting outstandings which come to light after the hand over. /30/.

According to AB92, paragraph 37, the client must call a review of the work no later than one year after the hand over /30/.

According to AB92, paragraph 38, the client or main contractor may call for an inspection no later than 30 days before five years have expired after the hand over /30/.

When all criteria have been complied with, operations are concluded and a completion report is prepared.

A completion report should be prepared which documents compliance with the completion criteria. The report should primarily include observations made at the inspection.

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