Sewage systems that are poorly maintained or virtually non-existent, untreated animal wastes, landfills that are poorly regulated and rising levels of industrial effluents are some of the reasons and issues behind contamination and wastewater generation. In fact, untreated sewage often tends to flow into the streets in rural areas (especially in developing countries) and can run into agricultural fields contaminating the clean water and food sources.
This paper will describe two distinct conceptual models for wastewater management and evaluate relevant issues such as water conservation, reuse and sustainability. Thereafter, the best model among the two shall be elaborated further and include a detailed description of the inherent wastewater management scheme. The paper also includes a detailed stakeholder analysis to ascertain the various issues affecting and influencing each stakeholder who is either involved or affected due to the prescribed wastewater management scheme.
The first model for wastewater management consists of a pilot plant system made up of an ASB (up-flow anaerobic sludge blanket), a CW (constructed wetland), SF (Intermittent sand filter) and AVB (Passively aerated vertical bed). This treatment model is highly flexible and can accommodate various wastewater treatment combinations. Each of these components is described below (Henze, 2005):
Anaerobic sludge blanket (ASB): the reactor segment of the plant is conical in shape and does not contain any gas separators for any initial treatment upon preliminary sedimentation. The average working volume of the reactor is 7.5 m3 and has a surface area of 8 m2. The ASB concept has been devised, developed and applied in many parts of the world, especially in the rural regions of developing nations such as China and Brazil (Rofe, 2004).
Aerated vertical bed (AVB): For the current consumption levels of 200 L/d per house, a passive aeration system consisting of four vertical beds can be