Waste management

Chemicals

The poor management of pesticide application leads to severe working environment problems. The regulation on pesticides is in general good, but suffers from an administrative division between several governing departments and legal acts. The enforcement is largely based on self-regulation: how many farmers comply with the requirements? Chemical spraying requires the chemicals to be loaded into the spraying machinery. Whether spraying by air or on land the loading of chemicals into the machinery can lead to chemical spills. These are typically not well controlled and the spills result in a build-up of toxic chemicals over time. Prevention is better than control, and as far as possible, spills should be prevented. However, if spills do occur these need to be well controlled. The collected spilled chemical could then still be used if kept uncontaminated in the contained area. Alternatively, the chemical can be properly treated and disposed.

Irrigation run-off can carry crop protection chemicals to surface/ground water, even if it takes many years for this to happen. In Denmark for example, fifty years after the use of pesticides began traces of them appeared in groundwater.

Other chemicals used on farms that have environmental effects include use of paints, turpentine, creosote, etc. which are often used in significant amounts for maintenance on farm property. The waste materials and containers are often not disposed in the correct manner leading to health and environmental effects of solvents, heavy metals and other problematic chemicals.

Container management

The management of waste chemical packaging is an important environmental, health and safety issue. Of particular concern are the containers from pesticide/herbicide chemicals. Once empty they need to be carefully managed. Prior to disposal, they must be thoroughly cleaned out. The rinsewater then requires treatment. Holes are then punched in the containers and they are flattened and disposed of. They are often not disposed of in correctly controlled waste sites. If not holed and flattened, the empty containers are in demand and may be stolen (e.g. for use as water containers in rural areas). There is a high probability of a health hazard for end users in this case.

Typically farmers are known to burn these empty plastic chemical containers as well as empty plastic fertiliser bags in open fire on farms. This low temperature burning results in emissions of dioxins which are hazardous to health and the environment. Air emissions (dioxins) from burning plastics (at temperatures <400°C) are carcinogenic and are therefore potentially harmful to those who inhale the fumes.

Vehicle use and maintenance

The maintenance of farm tractors and trucks for transport results in the generation of used oil and oil filters amongst other wastes. Thousands of litres of used oil and numerous oil filters could be generated on a farm each year. Typically these wastes are poorly managed as they are most often burnt on site, and the metal of the oil filters is buried. The carbon and emissions from burning dirty oil and heavy metal wastes from filters are of environmental concern.

If not burnt, waste oil is often used as wood treatment for fence posts on farms. Although this is common practice, according to hazardous waste management practices, it is discouraged and correct treatment and disposal of waste oil is recommended.

Soil management

Monoculture can affect the local ecosystem and it is therefore wise that the method of rotation crops is used. If the same crop is grown on a piece of land year after year after year, the disease organisms that attack that crop will build up in the area until they become uncontrollable. Nature abhors monoculture: inspection of natural plant and animal environments will reveal a great variety of species. If one species becomes too predominant, some event, pest or disease is likely to develop to strike it down. Man has managed to defy this law, to date, by the application of stronger and stronger chemical controls, but the pests (particularly the fast-evolving viruses) adapt very quickly to withstand each new chemical and to date the chemist has managed to keep only a short jump ahead of the disease.

The application of fertilisers requires good knowledge of soil, as adding too much can lead to destruction of the quality of the soil. Long-term use of fertilisers in one area also can have negative effects and it is important to use more natural methods of restoring soil quality.

Soil erosion is also an environmental effect associated with poor agricultural methods.

Dust

Some herbicides and pesticides remain in the upper soil layer and the dust generated during cultivation readily transports these to vulnerable and edible crops. Presence of dust on plants (near roads, etc.) encourages a build up of scale and red spider mites in cotton, citrus and other crops.

Solid waste generation

The wastes of concern that are generated on the farm are the hazardous wastes. These are not in very large quantities, but their effect on the environment demands improved management of these. Plastic and PVC wastes are not necessarily hazardous unless burnt at low temperature. Fluorescent lighting tubes contain mercury and are considered hazardous wastes. Used batteries are another typical solid hazardous waste generated on farms (particularly from workers houses) and may be in large quantities. All of these require careful environmental management.

General (low-/non-hazardous) solid waste generated by homestead as well as from workers’ housing and compounds, is also an important environmental management issue, mainly because of the volumes required for disposal. In many rural areas where farms are located, municipal dumps are located too far away for proper disposal of solid waste to be economically feasible. The burning of domestic waste and informal ‘landfilling’ (dumping) is very common. However, this has potential environmental problems that need to be addressed. Burning of plastics and polystyrene must be avoided, and location of sites where wastes are buried must be carefully chosen away from environmentally sensitive areas. Hazardous wastes should not be burnt or buried informally. A large portion of typical solid waste streams can be minimised through the use of reduction, reuse and recycling options.

Segregation of waste streams at source is essential to allow for improved waste management.

Source: Claire Janisch

Farmers can control and run their own mini-municipalities by separating plastic, paper, cans and glass, utilising a small mobile machine to bale refuse into manageable sizes. There are buyers for industrial refuse.