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Wednesday, July 30, 2008

Categories of Recyclables

8.
Categories of Recyclables

1. Plastics
The vast difference in the types of plastic materials that can be recycled is the largest barrier to the recycler. While all plastic can in general be recycled, the degree of contamination and the receipt of mixed plastic types at the washing and processing plants is an important complicating factor. Plastic waste is normally recycled by melting it down and extruding it into strings that are eventually cut up in pellets that are bought and used (in combination with virgin plastic pellets) by the local plastic converter industry. In some cases, local plastic waste materials are also recycled (by injection moulding) into items such as plastic pegs and cloth hangers.

2. Paper
According to a recent study (done for the year 2002 by the Packaging Council of South Africa (PACSA) (ref 8-7)) 922 000 tons of paper are reprocessed each year, giving South Africa a 52% recovery rate. This compares favourably with a world average of 47%. In Germany, where there is recovery legislation, the rate is more than 70%. The rates in the UK and US are about 45%.

3. Glass
In the glass recycling industry the strategy to recover waste glass is focused primarily towards providing igloos and glass banks in specific areas such as in schools and in community or Council operated sorting stations and drop off sites.

The current production volume of the Consol Glass plant in Cape Town stands currently at about 1400 tons per month. As this is the only glass smelter situated in Cape Town and since the transport or shipping of glass to another smelter is not economically viable it can be safely assumed that all the glass recovered and collected in Cape Town is actually processed in that smelter (in fact 70% of all the glass waste in the Western Cape gets recycled at the Consol plant in Cape Town). About 40 % of the glass recycled comes straight from bottle filling companies such as Coca Cola, South African Breweries etc. with the remaining 60% coming from post-consumer sources. Consol is currently significantly expanding the recycling of glass bottles in Cape Town and according to Consol the glass recycling volumes in Cape Town increased by about 50% in the last 8 months.

4. Beverage Cans
Approximately 4 879 tons of beverage cans have been recycled in the Western Cape over a 12 month period. It was estimated that 10% (450 to 500 tons) of this figure was received from outside the City of Cape Town. The prices paid for the recycled beverage cans are largely dependent on whether or not the collector has the transport to drop off the cans at the depot.

5. Ferrous and Non ferrous metals
The selection of these materials for recycling is mostly based purely on visual identification and hand or bulk sorting.

6. Oil Recycling
There are two main collectors of spent oil in Cape Town: Oilkol and Fuel Firing Systems (FFS) Refiners. Oilkol collects used oil on behalf of the Rose Foundation. This Foundation was formed by 12 national members from the lubricating industry who, on a voluntary basis, donate 9c for each litre of oil sold in order to finance the work of the Oilkol. The Rose Foundation, Oilkol collects about six million litres of used motor oil in Cape Town alone. All oil is sold to FFS who reprocess this oil waste to industrial fuel oil that is utilized for example as an energy source for cement kilns. Currently the oil recycling business in Cape Town provides about 20-30 jobs.

7. Electronic Waste
Present electronic waste types and volumes disposed of in Cape Town are largely unknown as no quantitative or qualitative research studies have ever been done on that subject. In a recent local workshop that was run by the Swiss Government organisation EMPA a first attempt was made to get local stakeholders together in order to assess the possible magnitude of the local e-waste problem. Types of ewaste identified through representatives from industry, commerce, private waste companies and local e-waste recyclers included predominantly items such as obsolete, broken or redundant: computer and other IT equipment, consumer electronics (such as cell phones, TVs, video players, stereo hi-fi systems etc and white goods (e.g. kitchen appliances -stoves, microwaves etc). Sources of e-waste are coming either directly from industries (e.g. stock of outdated appliance designs) or to a smaller degree from the households. The full lifecycle of most e-waste items is unknown but it is estimated that the large majority of e-waste items ends up at general waste landfill sites and to some degree (mostly from large industrial waste sources) at Vissershok where they are co-disposed. The origin of most e-waste items comes from outside of South Africa as most electronic products are imported by South Africa.

The City of Cape Town has over the past two years been chipping all green waste and had the chipped material sold to private compost manufacturers, thereby saving landfill airspace. This resulted in a 25% diversion of green waste from landfill. Other initiatives also included pilot projects in crushing of builders’ rubble, which could be reused in the industry. Despite all of the above, there is still an increasing amount of waste landfilled.

POLLUTION NEWS
http://pollutionnews.blogspot.com/
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

Waste Minimization

7.
Waste Minimization


“Waste minimization comprises any activity to prevent or reduce the volume and/or environmental impact of waste that is generated, treated, stored or disposed of”.

Polokwane Declaration
The Polokwane Declaration, formulated in 2001 by members of Government (at National, Provincial and Local level), selected industrial representatives and civil society, states that there is a need for urgent action to reduce, reuse and recycle more waste. Furthermore the represented sectors recommitted themselves to the objectives of integrated pollution prevention and waste minimisation. The goals agreed on were a 50% reduction of waste generation and a 25% reduction in disposal by 2012 as well as the development of a plan for Zero Waste by 2022.

Source Reduction
The aim of source reduction is to promote sustainable development by PREVENTING the generation of wastes and the unnecessary and wasteful utilisation of resources such as water, energy and raw materials. The first and most important element of any waste management strategy is therefore waste prevention through source reduction.

Waste Reuse and Waste Exchange:
REUSE must not be confused with RECYCLING. Reuse of a product does not constitute a change in its physical or chemical properties. Reused waste materials (in
their original state) are often assigned a new purpose and “lease of life” e.g. by using an empty ice tub as a storage container or by increasing their values (e.g. through a restoration and/or repair).

An Integrated Waste Exchange (IWEX) website has been developed and launched by the City of Cape in May 2000 in a bid to reduce hazardous and general waste material going to landfill. The website service at
http://www.capetown.gov.za/IWEX, provides an "electronic market place" for unwanted and wanted waste resource materials. IWEX forms the information interface between companies and communities willing to trade waste according to the motto: ‘Your trash is your neighbour's treasure.’ The IWEX site lists all nationally available and requested waste materials where special emphasis is placed on reducing hazardous waste volumes and expanding traditional recycling markets in and around Cape Town.

Waste Recycling
Recycling entails the physical product manufacturing from waste materials which is only done by local businesses who are technically equipped to be able to change the properties of a former waste material into a new product (e.g. making plastic pellets out of plastic waste, melting waste glass for new bottles and melting beverage cans for new steel appliances.

There is a distinction between close loop and open loop recycling. Close loop recycling happens either within the same company where waste materials from one process is “internally recycled” for another process step or it is a situation where companies exchange each others waste materials for recycling without any other outside waste streams incorporated.

POLLUTION NEWS
http://pollutionnews.blogspot.com/
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa 2006
Available to Distance Learners on www.dlist-benguela.org

Leachate Management

6.
Leachate Management


Leachate is the liquid component which filters through a waste body, and is a mixture of rainwater which has seeped through the waste, water soluble chemicals, by-products of microbial action and liquid from the waste itself. Leachate is a highly contaminating effluent and modern sanitary landfills prevent leachate from seeping into the groundwater by means of liners and drainage systems which collect the leachate. Once leachate is collected it can either be treated on site or can be pumped or tankered off to a waste-water treatment plant. Should the landfill be situated close to a waste-water treatment plant, then the latter option would be favoured eg Bellville landfill and Coastal Park landfill. The Vissershok landfill is far from the nearest wastewater treatment works (Potsdam, Athlone and Raapenberg), and for this reason it was more economical to construct a leachate treatment plant at Vissershok. This will reduce the transport costs of tankering the leachate off-site. The other benefit of treating the leachate is the fact that the treated effluent could be used for dust suppressing on the on-site roads and the area close to the working face. This prevents the operator from using potable water in a water-scarce region.

It is important to run laboratory trials first before embarking on a full-scale leachate treatment plant to assess the leachate treatability. The destination of treated effluent needs to be determined prior to process design, so that appropriate treatment can be provided. There are many different leachate treatment plants that could be designed, and the Vissershok as well as the Mariannhill landfill sites makes use of a sequencing batch reactor (SBR) system. The SBR makes use of aerobic biological primary treatment processes, followed by a secondary polishing process via a reedbed.

The objective of the SBR is to reduce two pollutants viz, the chemical oxygen demand (COD) fraction, and the ammoniacal-N fraction. The ammonia is converted to nitrates and nitrites by means of the Nitrosomonas and the Nitrobacter bacteria. This is the nitrification stage of the process. During the denitrification stage, the nitrates and nitrites are converted into free nitrogen. At the Vissershok plant only the
nitrification stage of the process is utilised, to save costs and due to the treated effluent being used for dust suppressing and not discharge into a water body. From the SBR the leachate is passed through a reedbed for final polishing. During this process further residual biodegradable COD, BOD and solids are removed through physical filtering through the root zones.

SBRs have proven to be robust systems, and are applied in many countries all over the world in varying climates. It is a relatively low-cost, easy to operate system.

POLLUTION NEWS
http://pollutionnews.blogspot.com/

Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

Friday, July 25, 2008

The Disposal of Hazardous Waste

5.
The Disposal of Hazardous Waste


The options available for the disposal of hazardous waste are:

1. Landfill
Hazardous waste may only be disposed of at a landfill designed specifically for the disposal of hazardous waste and legally permitted by the Department, in terms of the Environment Conservation Act. Hazardous waste landfills are classified as either H:H, which can accept all hazardous waste that can be landfilled, or H:h which can only accept hazard rating 3 and 4 waste, and general waste. Hazard rating 1 and 2, which are highly toxic in nature, may only be disposed of in a permitted H:H site.

The total loads per hectare of disposal cannot be exceeded, irrespective of whether the site is designed as a H:H or H:h site. Co-disposal of general waste with hazardous waste at landfills are often carried out to absorb, dilute and neutralise any liquids and to provide a source of biodegradable materials in order to encourage microbial activity that will assist in the degradation of hazardous substances. The ratio of hazardous waste to general waste needs to be determined as per formulae in
the Minimum Requirements.

Landfill disposal restrictions include certain solvents (due to its effects on liners, etc), flammable waste, corrosive waste and reactive wastes. Explosive wastes, waste compressed gases and radioactive waste are prohibited for disposal by landfill.

2. Incineration
Incineration is the preferred means of disposal for most organic and selected inorganic hazardous wastes. This process involves the controlled combustion of waste materials to reduce these to a non-combustible residue or ash and exhaust gases, ie carbon dioxide and water. The need for considerable atmospheric pollution control equipment, the sophistication of the equipment required for the safe handling and analysis of highly toxic materials, and the need for highly trained staff all contribute to the high cost of incineration. Waste typically incinerated includes infectious waste and medical waste.

Other aspects included in this volume are waste handling, storage and transportation, hazardous waste classification tables, toxicity characteristic and acid rain leaching procedures, hazardous waste treatment technologies and determining the hazard rating.

Volume 3 of the series is entitled “ Minimum Requirements for Water Monitoring at Waste Management Facilities”. This volume deals with borehole types and data, casing, screens and filters, monitoring networks, water sampling, sampling frequency, analytical variables and reporting to the Department.

POLLUTION NEWS
http://pollutionnews.blogspot.com/
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

Minimum Requirements

4.
Minimum Requirements

Waste may only be disposed of on a landfill that has a permit from the Department of Water Affairs & Forestry (DWAF), in accordance with Section 20 (1) of the Environment Conservation Act, Act 73 of 1989.

To set standards and help with the issuing of permits, the Department has published a Waste Management Series, consisting of three documents which cover

(i) Minimum Requirements for the Handling, Classification and Disposal of Hazardous Waste

(ii) Minimum Requirements for Waste Disposal by Landfill

(iii) Minimum Requirements for Water Monitoring at Waste Management Facilities

The second edition was published in 1998 and a third edition is due shortly. These documents contain waste management guidelines and the minimum standards that must be met to protect the environment. The Department requires that anyone dealing with waste should at the very least meet these standards and guidelines – hence the term Minimum Requirements.

The Minimum Requirements are there to ensure that waste does not cause pollution, be it in waste collection, transport, treatment or disposal. If a landfill site cannot meet the requirements, it will not be given a permit to operate. Sites that are permitted must be externally audited at least annually in the case of general sites, and twice annually in the case of hazardous sites. These audits are generally compliance audits. In instances where existing landfills are unable to comply with the appropriate Minimum Requirements within an agreed period, they may have to be closed in accordance with the Minimum Requirements for closure.

Landfilling is environmentally acceptable if properly carried out, but should it not be
managed properly, has the potential to have adverse impacts on the environment.
These impacts may be divided into short terms impacts or long term impacts. The
former include problems such as noise, flies, odour, air pollution and aesthetics.

Short term impacts arise generally due to poor waste disposal operations. These impacts should cease with the closure of the landfill. Long term impacts include problems such as pollution of surface and ground water and landfill gas generation. These problems are generally associated with incorrect landfill site selection, design, preparation or operation and may persist long after the landfill site has been closed. The approach to the Minimum Requirements is based on the Integrated Environmental Management (IEM) approach. This promotes the proactive control of pollution, by integrating environmental aspects into the planning of developments.

The general characteristics of Minimum Requirements are as follows:

􀂃 The rule rather than the exception decides a Minimum Requirement

􀂃 Minimum Requirements tend to concentrate on objectives and principles, rather than on detail.

􀂃 Numerical requirements have been used with discretion

􀂃 The degree to which a Minimum Requirement is applicable is not specified

􀂃 Accepted principles are adopted

􀂃 Historically accepted practice is the basis for certain Minimum Requirements

􀂃 Practicality often dictates less than the ideal, so that Minimum Requirements will sometimes fall short of the ideal.

􀂃 The Minimum Requirements address basic administrative procedures.

Volume 2 of Minimum Requirements covers Waste Disposal by landfill.

The commissioning of a new landfill follows at the end of a lengthy process. This process includes long term planning and information gathering, as well as early consultation with interested and affected parties (I&APs), stakeholders and communities. The key areas of attention are site selection, landfill design, landfill operations, landfill closure and monitoring

Good landfill site selection provides for simple cost-effective design, which, provided the site preparation is correctly carried out, provides for good operation. The criteria which would influence landfill site selection will include economic considerations, environmental considerations and public acceptance considerations. The design of the landfill is based on the outcome of the site investigation and environmental impact assessment. The design must minimise the risk of water pollution by leachate and make provision for sufficient cover to isolate the waste body from the environment. Sufficient cover must be provided for both the landfill operation and final closure and end-use. It is a Minimum Requirement that landfills be operated in accordance with the following sanitary landfill principles:

􀂃 The compaction of waste
This reduces voids in the waste, thereby reduces the chances of channelling which promotes the rapid infiltration and migration of any leachate formed. It also reduces the risk of fires, discourages vermin, controls litter, reduces the amount of cover required and increases site life.

􀂃 The covering of waste on a daily basis
The main purpose is to eliminate odour. It also reduces scavenging and generally improves aesthetics.

Closure of a landfill will involve the application of final cover, topsoiling, vegetating, drainage maintenance, gas management and leachate management. Any remedial design and rehabilitation must be based on appropriate investigation. After closure, the landfill can then be utilised in terms of its designed end-use. All landfills except those closed prior to August 1990, must be permitted before they can be considered legally closed. Landfills closed prior to 1990 may need to be rehabilitated if considered necessary by the Department.

Monitoring is a control mechanism which is applied throughout the development of a landfill. During the site preparation and liner placement, operation, rehabilitation and post-closure the impact of the landfill on the environment is always considered. The monitoring includes gas monitoring and water quality monitoring. Post-closure monitoring may occur for up to 30 years or more after the closure of the site.

Volume 1 of Minimum Requirements covers issues pertaining to the handling, classification and disposal of hazardous waste. The objectives are as follows:

􀂃 Promote the avoidance, re-use, recycling and treatment of waste 􀂃 Develop a waste classification system whereby waste can be classified according to the risk it poses

􀂃 Provide controlling authorities, generators, transporters and managers of waste with guidelines so that hazardous waste can be effectively controlledfrom generation to safe disposal (cradle-to-grave)

􀂃 Prevent hazardous waste entering the environment illegally

􀂃 Effectively manage and administer the issuing of waste disposal site permits

The following principles considered internationally as being essential for the management of hazardous waste are also acknowledged in the Minimum Requirements. They are:

􀂃 Duty of care – the generator retains the ultimate responsibility for ensuring that the waste is handled, stored, transported and disposed of according to the legislation and in an environmentally sound and responsible manner.

􀂃 Polluter pays principle – the person or organisation causing pollution is liable for any costs involved in cleaning it up or rehabilitating its effects

􀂃 Precautionary principle – waste or an identified contaminant is highly hazardous or toxic unless otherwise proven.

POLLUTION NEWS
http://pollutionnews.blogspot.com/
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

Landfill Sites, Transfer Stations and Compost Plants

3.
Landfill Sites, Transfer Stations and Compost Plants


The CoCT operates four landfill sites (three general and one hazardous), two refuse transfer stations and two compost plants. Until 2004 six landfills were operational, but two had to close due to a fatal flaw on one of the facilities and the other due to lack of airspace. A fatal flaw is a risk posed by the landfill that no engineering can rectify or guarantee potential pollution to the surrounding environment. By 2013, a regional landfill site should be operational, as two further landfills would have closed by then.

Landfills as a disposal option of last resort has a place in any Integrated Waste Management strategy, but if not correctly operated, can be both environmentally destructive and economically wasteful. South Africa still disposes 90% of its waste in landfills. Despite increasing environmental legislation, waste disposal by landfill is still the cheapest form of disposal, but managing landfills properly can be both demanding and expensive. Two environmental concerns for landfill operators are leachate management and gas management, methane gas in particular. Although both have their negative effects, they could also prove to be beneficial if properly utilised. Leachate could be treated and used as a dust suppressant, whereas methane gas, although explosive, is a clean burning fuel source and could be harvested for energy or electricity.

Where landfills are located too far away for a collection vehicle to dispose of its waste, refuse transfer stations are established to reduce wear of the vehicle and it reduce travel distances. This will also enable the collection vehicles to complete its collection beat as well. The waste at the transfer stations are then fed onto a conveyor system, from where it goes into a hopper and then compacted into a closed container. These containers are then transported either via road network or rail infrastructure to the landfill. Where landfills are closer to the transfer station, road transport seems more economically viable, but when the landfill is a huge distance away, rail transport may be favourable. The break-even point between road vs rail is between 25-40km. Anything less than 25km implies road transport is better and anything over 40km implies rail to be favourable. It is useful to have both options available, in order for the transportation cost to be competitive. As landfill sites close, the need to construct a waste transfer station becomes greater. However, in line with the Polekwane Declaration and the National Waste Management Strategy (NWMS), waste needs to be minimised and all future transfer stations would need to have a waste minimisation component, be it a materials recovery facility (MRF), compost plant, rubble crushing operation, chipping of green waste, etc.

Composting can be defined as the biological decomposition of organic wastes under controlled aerobic conditions, and at elevated temperatures. Composting stabilizes degradable materials and reduces their volume, conserving landfill airspace and decreases the risk of pollution from landfill gas and leachate. By the end of the process, most of the original contents of the heap have been broken down and mixed together to produce a rich, healthy soil conditioner for the garden. There are many different options for composting. They include the use of windrows, forced aeration composting and mechanical composting systems. Trenching, worm composting and layering are more conventional home-composting methods. Ideal material to compost would be annual weeds, cut grass, leaves and soft prunings, most kitchen waste, newspapers, sawdust, horse and cow manure, rabbit droppings and seaweed. Avoid using tough perennial weeds, plants treated with weed-killer, prickly or hard prunings, cooked food, magazines and colour newsprint, dog and cat waste.

POLLUTION NEWS
http://pollutionnews.blogspot.com/
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

Thursday, July 24, 2008

The Operational Components of Waste Management

2.
The Operational Components of Waste Management


The waste management operations consist of waste collection, area cleaning and waste disposal. Waste collection and Area Cleaning constitute the core functions of waste management. Resources between the two operations are often shared or integrated. A Collection beat is defined as an activity that is covered by a specific collection vehicle per day. The CoCT is currently divided into 601 department refuse collection beats serving 473 400 erven and a population of approximately 2.5 million people. Approximately 560 000 tons are collected annually from 744 000 formal (81%) households and informal (19%) service points.

There are three levels of collection service, ie a containerised service (240l “wheelie” bins), plastic refuse bags (85l) and skips for rudimentary services. The CoCT contracts out the skip collection services and certain other collection services. The CoCT’s collection vehicles account for approximately 33% of the total waste disposed of to landfill.

Area Cleaning comprises street sweeping, litter picking, beach cleaning, clearing of illegal dumping, animal carcass collection, provision and servicing of litter bins, clearing hawker waste and provide water tanker services for control of wind-blown litter. The CoCT undertakes most of the area cleaning activities, although a number of other departments outside of Solid Waste also engage in area cleaning. More than 95% of the CoCT’s inhabitants receive an effective service in terms of waste collection and area cleaning.

Once waste has been collected or areas have been cleared it needs to be disposed of. Waste disposal entails the landfilling of waste, provides refuse transfer stations and drop-off facilities and compost waste at two facilities. Modern landfills aim to contain waste safely and hygienically in specially engineered cells in the ground. Legislation governing the siting, design, engineering and operation of sanitary landfills aim to combat potential environmental problems. A landfill should be a reasonable distance away from any human habitation, but close enough to where domestic waste is generated to limit transportation costs. The underlying soil structures, soil type and drainage patterns of a potential site must also be taken into account in order to minimise the impact of the landfill on the surrounding environment. The landfill is usually lined with clay or high density polyethylene (HDPE) to protect the underlying groundwater from leachate infiltration. Waste deposited in the lined cells are compacted and covered daily to prevent the waste from blowing around and discourage animals and vermin, reduce odours and saves landfill airspace. The decomposition of waste is by both aerobic and anaerobic bacteria and can continue for many years from date of deposition. Once a landfill is closed, it is rehabilitated, capped and may be used as public open space, sports fields or agriculture. Under no circumstances may it be used for housing, due to the risk posed by settlement of the waste and the generation of methane gas, which is explosive.

POLLUTION NEWS
http://pollutionnews.blogsopt.com
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

WASTE Management

Environmental Engineering
WASTE
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”

1.
WASTE Management


The field of waste management is often highly underestimated in its complexity, not only by the community, but by senior officials as well. It is mainly due to this fact that waste management issues are often an afterthought rather than a carefully planned, integrated component of development and services. It needs to fit in with the Constitutional rights of the citizens of the country, as well as the Integrated Development Plan (IDP) of the city. Waste management itself needs to have its own subset of an Integrated Waste Management Plan (IWMP), which will be compulsory on all major metropolitan cities in the near future. It is therefore very important that waste management activities be carefully planned, sometimes over long periods of time, before implementation can occur in order to ensure a successful outcome.

The field of waste management itself is multidisciplinary and encompasses management, financial, environmental, legal, engineering, chemical, biological, logistical, social and entrepreneurial issues.

Waste is defined as “an undesirable or superfluous by-product, emission, residue or remainder of any process or activity, any matter, gaseous, liquid or solid or any combination thereof,…” (Government Gazette, 24 August 1990). A more simplistic definition defines waste as “anything that we have used that is not being reused and has not been absorbed back into nature. It can be solid or liquid and we must find somewhere to put it, or some way to reuse or recycle it.” (Wise up on Waste, 5th Edition, FCA). Wastewater effluents are not defined as waste as they are regulated and controlled by the Water Act (1998). Similarly, radioactive waste is regulated and controlled by the Nuclear Energy Act (Act 92 of 1902) and the Hazardous Substances
Act (Act 15 of 1973). Sewage sludge from sewage works and building rubble contaminated by other waste or not used for fill would fall under the definition of waste.

Waste is divided into two classes in accordance with the risk it poses: General Waste and Hazardous Waste. General waste refers to any waste that does not fall within the definition of Hazardous Waste. This waste does not pose a significant threat to public health and the environment if properly managed. Examples would include domestic (although it may contain small quantities of hazardous substances), commercial, certain industrial wastes and builder’s rubble. General Waste may be disposed of on any landfill that is permitted in terms of the Environment Conservation Act. Hazardous Waste is waste that has the potential, even in low concentrations, to have a significant adverse effect on public health and the environment because of its inherent toxicological, chemical and physical characteristics. Hazardous Waste requires stringent control and management, to prevent harm or damage and hence liabilities. It may only be disposed of on a hazardous waste landfill. A further classification, termed the hazard rating, differentiates between hazardous waste that is fairly or moderately hazardous and one that is extremely hazardous. Hazard Rating 3 (moderate risk) and/or 4 (low risk)
waste and can be disposed of on a landfill site classified as H:h, whereas Hazard Rating 1 (extreme risk) and/or 2 (high risk) waste can only be disposed of on landfill
sites classified as H:H.

General waste landfills are classified in terms of their potential to generate leachate. This ensures that the risk of water pollution from leachate is identified at the earliest opportunity.

Any landfill has the capacity to generate sporadic leachate in excessively wet weather conditions. It is only necessary to install leachate management systems (liners, drains and removal systems) when leachate generation could impact adversely on the environment. Significant leachate generation requires to be managed by means of a proper leachate management system, whereas sporadic leachate, while requiring some management does not warrant a costly leachate management system.

The Climatic Water Balance (B) is defined by the difference between Rainfall in mm of water ( R ) and Evaporation from the soil surface (E). The value of B is calculated for the wet season of the wettest year on record, and then recalculated for drier years. If B is positive for less than one year in five for the years for which data is available, then there should be no leachate generation on account of the climate and
the site would be classified as B- . No leachate management system should thus be necessary. If B is positive for more than one year in five for the years for which data is available, there should be significant leachate generation and the site will be classified as B+. A leachate management system would now be required.

B = R – E
As a rough guide: If R > E, then B = B+ and if R < b =" B-."> 25 and <> 150 and <> 500

A site classified as GLB+ would therefore indicate that the site is a general landfill, receives over 500 tons of waste per day, and requires leachate management due to the climatic balance or moisture content of the waste.

POLLUTION NEWS
http://pollutionnews.blogspot.com
Sumber:
Core Notes for Module 6 (Elective) of the Course
“Environmental Engineering – Sustainable Development in Coastal Areas”
Cape Peninsula University of Technology (CPUT)
Cape Town, South Africa
2006
Available to Distance Learners on www.dlist-benguela.org

Saturday, July 19, 2008

Unhealthy statistics

Numbers can tell a story, and the numbers show that the quality of Indiana's air and water has been seriously compromised. [News Source]

ethanol from overseas

Not only have politicians been manipulating the cost of domestically produced ethanol, they've been guaranteeing that you can't buy cheaper ethanol from overseas. [News Source]

You can cut down air pollution risks.

Every month, it seems, there's a new study suggesting smog, dust or airborne chemicals can cause death and disease. [News Source]

Thursday, July 10, 2008

Pollution News

Article, Idea and Product of Pollution Environmental Health.