Decentralized wastewater system
[4] They collect wastewater in large and bulk pipeline networks, also referred as sewerage, which transport it at long distances to one or several treatment plants.
In such cases decentralized wastewater facilities are considered as a temporary solution, but they are mandatory, in order to prevent public health and ecological problems.
In this context, decentralized solutions are favorable in their ability to be locally applied as needed, while still carrying the potential to cover large areas at lower costs.
[7] In the specific case of developing countries, where localities with poor infrastructure are common, decentralized wastewater treatment has been promoted extensively because of the possibility to apply technologies with low operation and maintenance requirements.
[6] Based on the size of the served area, different scales of decentralization could be found:[citation needed] Usually they are applied at on-site level and are adequate because of the very low wastewater quantity generated.
However, the design and operation of small treatment plants, especially at neighbourhood or on-site level, present significant challenges to wastewater engineers, related to flow fluctuations, necessity of competent and specialized operation and maintenance, required to deal with a large number of small plants, and relatively high per capita cost.
[13] Water pollution regulations in the form of legislation documents, guidelines or ordinances prescribe the necessary level of treatment, so that the treated effluent meets the requirements for safe disposal or reuse.
[12][citation needed] In the case of decentralization at on-site level and clusters of buildings, the whole wastewater system is located within private premises.
From regulatory point of view, the control of the quality of treated effluent for reuse, discharge or disposal is entirely the responsibility of local or national government authorities.
[15] In the cases of new urban/rural developments, or the retrofitting of existing ones, it is advisable to consider different alternatives regarding the design of the wastewater system, including decentralized solutions.
[16] [17] From this perspective, centralized solutions might be more appropriate in many cases, depending on existing sizes of plots, topography, geology, groundwater tables and climatic conditions.
But when applied adequately, decentralized systems allow for the application of environmentally friendly solutions and reuse of the treated effluent, including resource recovery.
Public awareness, perceptions and support play an important part in the urban planning process for choosing adequate wastewater systems which fit the specific context.
The treated effluent is reused for irrigation of the surrounding green areas, but the study registered outflow from the wetland only during periods of heavy rains.
[23] EcoSwell establishes decentralized wastewater systems with the help of local residents and interns, including communal biodigesters, dry toilets, and greywater reuse projects.
