OVERVIEW WASTE MANAGEMENT IN CONSTRUCTION INDUSTRY

Waste management varies from developed to developing countries. The main aim is to reduce the adverse effects of waste materials on human being and the environment. Waste management may be defined as dicipline associated with the control of generation, storage, collection, transfer and transport, processing, and disposal of the waste in a manner that in accord with the best principle of public healths, economics, engineering, conservatives, and other environmental considerations and that is also responsive to public attitudes. In its scope, waste management includes all administrative, financial, legal planing and engineering functions involved in solutions to all problems of waste.

Functional Elements of a Waste Management System

The problem associated with the management of waste in today’s society are complex because;

1. The quantity and diverse nature of the wastes
2. The development of sprawling urban areas
3. The funding limitations for public services in many large areas
4. The impacts of technology
5. The emerging limitation in both energy and raw materials

As a consequence, if waste management to be accomplished In an efficient and orderly manner, the fundamental aspects and relationships involved must be identified, adjusted for uniformity of data and understood clearly. The activities associated with the management of solid waste from the point of generation to final disposal have been grouped into six functional elements;

1. Waste generation
2. Waste handling and separation, storage, and processing at source
3. Collection
4. Separation and processing and transformation of waste
5. Transfer and transport
6. Disposal

The views of functional elements that constitute a waste management system: (a) Waste generation, (b) Waste handling and separation, storage, and processing at source, (c) Collection (d) Separation and processing and transformation of waste, (e) Transfer and transport, and (f) Disposal are as below:

(a)          (b)            (c)

(d)            (e)          (f)

The interelationship between the elements is identified as figure below.

Sustainable Waste Management

Sustainability of waste management is vital to providing an effective service that satisfies the needs of the stakeholder. Sustainable integrsted solid waste management can be defined as the selection and application of suitable techniques, technologies, and management programs to achieved specific waste management objectives and goals (Tchobanoglous, Theiseu & Vingil, 1993). A hierarchy of waste management activities adopted by the US Environmental Protection Agency (EPA) is composed of following elements; source reduction, recycling, waste transformation and landfilling (disposal) and illustrated as below:

The highest rank of sustainable integrated waste management, source reduction, involves reducing the amount of the waste that are now generated. Source reduction is first in the hierarchy because it is the most effective way to reduce the quantity of the waste, the cost associated to with its handling, and its environmental impacts. Waste reduction may occur through design, manufacture and pacaking of products with minimum toxic content, minimum value of material, or a longer useful life.

The second highest rank in the hierarchy is recycling. Recycling is an important factor in helping to reduce the demand on resources and the amount of waste requiring disposal by landilling. Recycling involves:

• Separation and collection of waste materials
• Preparation of these materials for reuse, reprocessing and remanufacture
• Reuse, reprocessing and remanufacture of these materials

The third rank in hierarchy, recovery, involves the physical, chemical or biological alteration of waste. The transformation of waste materials usuallyresult in the reduced use of landfill capacity. Typically, the physical. chemical or biological transformatios that can be applied to the sustainainable waste management are used;

1. To improve the efficiency of waste management operations and systems
2. To recover reusable and recycleable materials
3. To recover conversion products (e.g. compost) and energy in form of heat and combustable biogas

Ultimately, something must be done with;

1. Waste that cannot be recycled and are of no further use
2. The residual matter remaining after the waste have been separated at a recovery facility
3.  The residual matter remaining after the recovery of conversion products or energy

There are only two alternatives available for long-term handling of waste and residual matter; disposal on or in the earth mantle, and disposal at the bottom of the ocean. Landilling, the fourth rank in the hierarchy, involves the controlled disposal or waste on or in the earth's mantle, and it is by far the most common method of ultimate disposal of waste residuals. Landillifg is the lowest rank in the hierarchy because it represents the least desirable means of dealing with society's waste (Tchobanoglous, Theiseu & Vingil, 1993).

Sources and types of waste

It will be helpful to define the various types of solid wastes that are generated (see table below). It is important to be aware that the definition of waste terms and classifications vary greatly in the literature and in it the profession.

Source	Typical facilities, activities, or locations where wastes are generated	Types of solid waste
Residential	Single family and multifamily detached dwellings, low-, medium-, and high rise- apartments, etc	Food wastes, paper, cardboard, plastic, textiles, ashes, electronics, yard waste, batteries, oils, household hazardous wastes, etc
Commercial	Stores, restaurants, markets, offices building, hotels, motels, print shops, repair shops, service stations, etc	Paper, cardboard, plastics, wood, food waste, glass, metals, hazardous waste, etc
Institutional	School, hospitals, prisons, governmental centres, etc	As above in commercial
Construction and demolition	New construction sites, road repair/renovation sites, razing of buildings, broken pavement, etc	Wood, steel, concrete, dirt, etc
Municipal services (excluding treatment facilities)	Street cleaning, landscaping, catch basin cleaning, parks and beaches, other recreational areas, etc	Rubbish, street sweepings, landscapes, and tree trimmings, catch basin debris, general waste from park, beaches, and recreational areas, etc
Treatment plant sites, municipal incinerators	Water, wastewater, industrial treatment processes, etc	Treatment plant waste, principally composed of residual sludges
Municipal solid waste	All of the above	All of the above
Industrial	Construction, fabrication, light and heavy manufacturing, refineries, chemical plants, power plants, demolitions, etc	Industrial process water, scrap materials, etc Non-industrial waste such as food wastes, rubbish, ashes, demolition and construction wastes, special waste, hazardous waste, etc
Agricultural	Field and row crops, orchards, vineyards, diaries, feedlots, farms, etc	Spoiled food waste, agricultural waste, rubbish, hazardous waste, etc

Source: (Tchobanoglous, Theiseu & Vingil, 1993)

As have been mentioned in the table above, waste from constructions, remodelling, repairing of individual residences, commercial buildings, and other structures are classified as construction waste. The quantity produced are difficult to estimate. The composition is variable but may include dirt, stones, concrete, bricks, plaster, lumbers, shingles, plumbing, heating and electrical parts. Waste from waste buildings, broken-out streets, sidewalks, bridges, and other structures are classified as demolition waste. The composition of demolition waste is similar to construction wastes but may include broken glasses, plastics and reinforcing steel. 

There are a variety of different approaches to the evaluation of the main origins, sources and causes of construction waste. The number of construction waste generation sources can be broadly categorised into 11 clusters. Table below shows that construction waste is generated throughout the project frominception to completion and the preconstruction stage has its considerable share. M. Letcher and A. Vallero (2011) stated that research on construction procurement systems-related waste sources showed that these fall under four main themes: 

1. Uncoordinated early involvement of project stakeholders
2. Ineffective project communication and coordination
3. Unclear allocation of responsibilities 
4. Inconsistent procurement documentation
   

Origins of Waste	Causes of Waste
Contractual	• Waste client-driven/enforced. • Errors in contract documents. • Contract documents incomplete at commencement of construction.
Procurement	• Lack of early stakeholders’ involvement. • Poor communication and coordination among parties and trades. • Lack of allocated responsibility for decision making. • Incomplete or insufficient procurement documentation
Design	• Design changes. • Design and detailing complexity. • Design and construction detail errors. • Inadequate/incoherent/incorrect specification. • Poor coordination and communication (late information, last minute client requirements, slow drawing revision and distribution).
On-site Management and Planning	• Lack of on-site waste management plans. • Improper planning for required quantities. • Delays in passing information on types and sizes of materials and components to be used. • Lack of on-site material control. • Lack of supervision.
Site Operation	• Accidents due to negligence. • Unused materials and products. • Equipment malfunction. • Poor craftsmanship. • Use of wrong materials resulting in their disposal. • Time pressure. • Poor work ethics.
Transportation	• Damage during transportation. • Difficulties for delivery vehicles accessing construction sites. • Insufficient protection during unloading. • Methods of unloading.
Material ordering	• Ordering errors (i.e. ordering items not in compliance with specification). • Over allowances (i.e. difficulties to order small quantities). • Shipping and suppliers’ errors
Material Storage	• Inappropriate site storage space leading to damage or deterioration. • Improper storing methods. • Materials stored far away from point of application.
Material Handling	• Materials supplied in loose form. • On-site transportation methods from storage to the point of application. • Inadequate material handling.
Residual	• Waste from application processes (i.e. over-preparation of mortar). • Off-cuts from cutting materials to length. • Waste from cutting uneconomical shapes. • Packaging.
Other	• Weather. • Vandalism. • Theft.

Source: (Osmani, 2011)

Issues Related to the Construction Waste

Construction waste is a prominent issue globally and has adverse effect on overall performance of a project as well as the society and nature. Waste can be generated in various forms. As indicated in figure below, the waste occurs in the form of material, time and cost losses.

Source: (Nagapan, Abdul Rahman & Asmi, 2012)

A. Materials waste as a physical construction waste

The major physical waste generated from construction activity is identified in the form of material waste like concrete leftover, demolished debris, steel scrap and others (Nagapan, Sasitharan & Abdul Rahman, Ismail & Asmi, Ade.,2011). Figures below show the examples of physical waste. Studies show that material waste has significant impact to the cost of the project as well as an adverse impact on environment. One of the implications created from huge quantities of material waste is illegal dumping. Illegal dumping is the unlawful deposit activity of waste onto land. This unethical activity always causes problems to the public in general and to the environment in many places around the world. Wrongly disposal of physical wastes are increasing and this contributes to pollution globally (Poon, Yu, Wong & Cheung, 2004).

                                    

Cement waste                                                    Waste Component

                                    

Surplus of reinforcement bar component waste        Concrete construction waste

Source: (Nagapan, Abdul Rahman & Asmi, 2012)

B. Cost and time overrun as non physical waste

Construction industries are extremely concerned about time and costs of the project. Most of these projects are having dilemma in cost and time overrun globally. The non-physical waste normally occurs during the construction process. Figures below are the axample of non physical waste.In contrast to the material waste, non physical waste occurs when materials are not physically lost but money and time overrun (Nagapan, Sasitharan & Abdul Rahman, Ismail & Asmi, Ade.,2011) can lead to failure for the majority projects. These problems are caused by poor financial management by the developers, wrong construction specification, construction delays, lack of supervision and lack of enforcement on existing rules. In other words, non-physical waste has an impact on economic growth and social development of countries.

                    

Design error leads to rework               Equipment failure leads to stoppage

Source: (Nagapan, Abdul Rahman & Asmi, 2012)

Construction Waste Minimization Strategies

Waste minimization, prevention and management are sometimes used interchangeably. Jacobsen and Kristofferson (2002) in their report on waste minimization practices in Europe gave a clear distinction between the three concepts and defined waste minimization as a set of three options prioritized according to the waste hierarchy. The first priority is waste prevention, the second is waste reuse and the third priority is waste recycle. Reducing the waste generated at source is considered as the first option to be implemented for better protection of the environment, and for better economic savings. A review of the literature suggests the following measures as the main solutions for efficient prevention of material waste on construction sites:

1. LOGISTICS MANAGEMENT

It has been the subject of many reports published by the Waste and Resources Action Programme in the UK where they emphasize the importance of implementation of a sophisticated Material Logistics Plan on-site for better waste reduction. In fact, logistics management is proven to prevent double handling and ensure the adequate handling of equipment to minimize damage to materials on-site.

2. SUPPLY CHAIN MANAGEMENT

It is based on long-term commitment with suppliers and subcontractors and on the win2win arrangements (Ofori, 2000). A good supply chain management can help to achieve just-in-time delivery in order to avoid waste due to long storage or to ordering unneeded materials .

3. MODERN CONSTRUCTION METHODS

A study published by WRAP (Waste & Resources Action Programme) in January 2007 shows that ‘the substitution of some modern methods of construction for traditional building methods resulted in a net reduction in waste levels’. Dainty and Brooke (2004) have reported the same finding in their survey of waste minimization measures implemented in the UK; they stated that there is an increased use of off-site prefabrication to control waste and damage on-site.

4.TRAINING AND INCENTIVIZING

A number of studies and government guides insist on staff training as one of the first steps in dealing with construction waste. Increasing the awareness could be through using toolbox talks or waste posters about the benefits and rules of waste on-site . In addition, incentives for good performers can contribute to meet the waste targets (Lingard et al., 2001). Reuse and recycling are usually treated together in the literature. Both these practices require a separation of waste streams in order to be accomplished. In fact, the good practice of waste minimization involves segregation of key waste streams namely: timber, plasterboard, packaging, general waste, inert waste, metal and hazardous by using clearly labelled skips or bins. Once the waste material is segregated, the possibilities of reuse or recycling on site must be investigated before considering any off-site recovery or disposal.