Surface Disposal (Solids)

This technology is primarily used for treated sludge, although it is applicable for any type of dry, unusable material which is not harmful to the environment or human health when being exposude to air or humidity . One application of surface disposal is the disposal of dry cleansing materials, such as toilet paper, corn cobs, stones, newspaper and/or leaves. These materials cannot always be included along with other water-based products in some technologies and must be separated. A rubbish bin should be provided beside the user interface to collect the cleansing materials and menstrual hygiene materials. Dry materials can be burned (e.g., corn cobs) or disposed of along with the household waste. For simplicity, the remainder of this technology information sheet will be dedicated to sludge since standard solid waste practices are beyond the scope of the Compendium.

This technology should only be considered as an option when there is no local interest for reuse of waste material. When there is no demand for or acceptance of the beneficial use of sludge, it can be placed in monofills (sludge-only landfills) or heaped into permanent piles. Temporary storage contributes to further dehydration of the product and the die-off of pathogens before it is used.

Landfilling sludge along with municipal solid waste (MSW) is not advisable since it reduces the life of a landfill (due to rapid fill up) , which has been specifically designed for the containment of more noxious materials. As opposed to more centralized MSW landfills, surface disposal sites can be situated close to where the faecal sludge is treated, limiting the need for long transport distances.

The main difference between surface disposal and land application is the application rate. There is no limit to the quantity of sludge that can be applied to the surface since nutrient loads or agronomic rates are not a concern. Attention must be paid, however, to groundwater contamination and leaching (see also water pollution) . More advanced surface disposal systems may incorporate a liner and leachate collection system in order to prevent nutrients and contaminants from infiltrating the groundwater (see also waste stabilisation ponds, leach fields,[ 681-soak pits] or evaporation beds) .

Sites for the temporary storage of a product should be covered to avoid rewetting by rainwater and the generation of leachate. 

If a surface disposal and storage site is protected (e.g., by a fence) and located far from the public, there should be no risk of contact or nuisance. The contamination of groundwater resources by leachate should be prevented by adequate siting and design or/and the sites should be located far away from water sources and at a sufficient distance from the maximum groundwater level (see also water pollution and water source protection). Care should be taken to protect the disposal or storage site from vermin and pooling water, both of which could exacerbate smell and vector problems.

Staff should ensure that only appropriate materials are disposed of at the site and must maintain control over the traffic and hours of operation. Workers should wear appropriate protective clothing.