What happens with a plastic bottle when you throw it away? Well, it might end up in a landfill however it could also be collected often by the informal sector, transported to a processing site washed and shredded into small pieces. These pieces could then be used as a raw material in the production of fibers for clothes, carpets or new plastic bottles. This process is a form of resource recovery that is probably happening around you. In this module we will introduce you to similar forms of resource recovery for fecal sludge. Following this module, you will be able to list different treatment products identify ways in which they can be used and learn important characteristics of resource recovery products. For over 2000 years excreta and fecal sludge from animals and humans have been used in many parts of the world as soil conditioner in agriculture. The water, organic matter and nutrients in fecal sludge are beneficial for soil properties and plant growth. The organic matter is beneficial for water retention which can increase water holding capacity and reduce the effects of drought reduce erosion of soils and benefit the soil microbial community and the water and the nutrients such as nitrogen, phosphorous and potassium are essential for plant growth. However, there are also other possible uses and types of treatment products than just soil amendments. Products from other established treatment technologies include compost from co-composting of fecal sludge and organic solid waste plants, for example from planted drying beds and effluent, for example from waste stabilization ponds. In addition, treatment technologies exist that are innovative and in development. These products and treatment technologies include Bio-gas, Bio-diesel, and Syngas for example from anaerobic digestion of fecal sludge insect larvae from the treatment of fecal sludge with fly larvae and Char from carbonization of fecal sludge. These treatment products can all have different uses. We already mentioned the use of Dewatered or dried sludge as soil conditioner, ranging from deeper entrenchment or untreated fecal sludge as soil conditioner. In addition this treatment product can also be used as a component in building materials or for the production of solid fuels. Compost and fertilizer can be used as soil conditioner in agriculture horticulture or forestry plant as animal feed effluent for irrigation in agriculture or for parks or golf courses Bio-gas, Bio-diesel, and Syngas as liquid bio-fuel insect larvae as animal feed, such as chicken or fish Char as a component for Bio-fuel brickette production or as soil conditioner. The aforementioned treatment products can also be further processed to increase the market value. For example Char from the carbonization of fecal sludge may be used for a soil conditioner. Further processing of char into brickettes puts into a form that could make it suitable for recovery of it's energy in households or institutions. Other examples include the combustion of Bio-gas or Syngas to produce heat or electricity, or pelletizing of compost or dried sludge. Pellets are more homogeneous in size they have a higher density of nutrients or energy in comparison with the sludge or compost before pelletizing and then therefore be easier to transport and store. Characterization of treatment products is important to ensure that they meet market needs and protect public and environmental health. On the next slide we will summarize what parameters are relevant for the different treatment products. Nutrients such as Nitrogen, phosphorous and potassium are essential for plant growth and important for the use of effluent for irrigation and soil conditioner, compost or fertilizer. Heavy metal such as Lead and Cadmium and the salinity are important as they can be toxic to plants. Indicators of pathogens such as E coli for effluent and Helminths eggs for soil conditioner composts or fertilizer should be determined to ensure that resource recovery adequately protects public health. The calorific value, a measure of the energy content of the fuel is important for the characterization of treatment products as solid fuel. The ash in fuels is an important indicator for the amount of inorganics contained in fecal sludge. it is the proportion of the fuel that does not burn and therefore does not contribute to the calorific value. Helminths eggs as an indicator of human pathogens in sludge is also an important parameter for the use of fecal sludge as fuel. The Methane content and the Carbon Dioxide content and the calorific value are important parameters for Bio-gas a higher Methane and lower Carbon Dioxide content increases the calorific value. The Protein, Fat and the Mineral content are important for the use of insect larvae and plants as animal feed. These parameters can be used to compare the product characteristics to the nutritional requirements of animals. Indicators of human pathogens such as E coli and Helminths eggs should also be regularly monitored for animal feeds in order to ensure that pathogens are not transmitted to animals. In this module we have learned what some products from treatment are and how they can be used. This includes effluent for irrigation and sludge compost as the soil conditioner, solid and liquid Bio-fuels plants as animal feed and as a component in building materials. Characterization of treatment products for parameters such as the caloric value as a solid fuel and the ratio of nutrients as soil conditioner compost of fertilizer are important to meet market needs. Helminths eggs and E coli are important indicators to ensure the protection of public health.
