Sanlexicon: A - B

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Activated sludge

Production of an activated mass of micro-organisms capable of stabilizing waste aerobically.

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Aerated pond

A natural or artificial wastewater treatment pond in which mechanical or diffused air aeration is used to supplement the oxygen supply.

Aerobic

Condition characterized by the presence of free oxygen.

Anaerobic digestion

Involves the decomposition of organic and inorganic matter in the absence of molecular oxygen.

Arborloo

The simplest type of non-urine diverting eco-sanitation latrine and the one that involves the least amount of behaviour change from the conventional pit latrine. A shallow pit (0.75 m is recommended) is dug and a slab and an easily movable superstructure are placed on top. The family uses the latrine, adding a mixture of soil and ash after each use, until it is three quarters full (which usually takes between 4 and 9 months). After this the slab and the superstructure are moved to another pit. A layer of soil is added to the full pit and a sapling is planted in the soil. The tree grows and utilizes the compost to produce fruit. After a few years the result is an orchard producing fruit with a good economic value.

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Aqua-privy

A simple type of latrine on which the excreta falls directly through a submerged pipe into a watertight settling chamber below the floor and from which the effluent overflows to a soak-away drain.

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Awareness raising

Awareness of the relevant issues (i.e. hygiene promotion and hygienic use of water, cost and services etc.) is necessary for effective participation and community ownership of schemes, for developing support for service charges and systems of tariff collection, and for introducing mechanisms for environmental protection.

Biological oxygen demand

The mass of oxygen consumed by the organic matter during aerobic decomposition under standard conditions, usually measured in milligrams per litre during five days. Typically acceptable BOD’s for discharge into surface water are 20-100 mg/litre, but local regulations need to be used.

Bellagio statement

Current waste management policies and practices are abusive to human well-being, economically unaffordable and environmentally unsustainable”. It calls for a radical overhaul of conventional policies and practices world-wide, and of the assumptions of which they are based. It states that the principles that should be applied to all sanitation programs are:

Human dignity, quality of life and environmental security which should be responsive and accountable to needs and demands in local setting. Decision-making should involve participation of all stakeholders, especially the consumers and providers of services. Waste should be considered a resource and its management should be holistic and form part of integrated water resources, nutrient flows and waste management processes. The domain in which environmental sanitation problems are resolved should be kept to the minimum practicable size (household, community, town, district, catchment, city) and wastes diluted as little as possible.

Biodegradable

Substances that can undergo biological decomposition.

Biodegradation

Is the process by which organic substances are broken down by other living organisms.

Biological oxygen demand

The mass of oxygen consumed by the organic matter during aerobic decomposition under standard conditions, usually measured in milligrams per litre during five days. Typically acceptable BOD’s for discharge into surface water are 20-100 mg/litre, but local regulations need to be used.

Black water

Wastewater contaminated by human and/or animal excreta.

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Blair Latrine/Ventilated improved pit latrine

A pit (either lined or unlined depending on soil conditions) is dug to a depth of around 2.5 metres and covered concrete slab (flat or domed). The slab which has been finished to a smooth surface to allow easy cleaning has foot rests to prevent foot fouling, a hole to take a ventilation pipe, and a drop hole to allow faeces to enter the pit. The slab is positioned so as to cover the whole of the pit and removes the need for providing supporting beams. A ventilation pipe is positioned on the slab to take the foul smells away from the pit and to vent it to the external air above the superstructure roof line. A fly screen is added to the top of the ventilation pipe to prevent the access and egress of flies. Designers usually specify a block or brick superstructure, a good quality zinc or concrete roof, no windows and a tight fitting door in order to keep the inside of the superstructure dark. This is done in the belief that flies hatching in the pit will fly to the sunlight shining through the ventilation pipe and not fly through the drop hole into the dark superstructure.

The VIP latrine is also known as the Blair latrine.

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