Figure 1: Schematic diagram of waste to energy technology
Environmental and energy concerns play an increasingly important part in the selection and design of the collection and treatment facilities of various wastes. Among the various options available for conversion of solid waste, biomethanation /anaerobic digestion appears to be the most desirable and viable for solid wastes with high organic and moisture content as it results in the production of biogas - a mixture of CH4 and CO2, a suitable replacement for various conventional fuels.
Brisanzia is involved in development of various technologies for solid and liquid waste treatment through anaerobic digestion and having technological tie ups with internationally reputed institution / organizations. Realizing the potential of domestic waste, fruit and vegetable market waste, semi-solid municipal waste and non-availability of any decentralized system for the treatment of these, efforts were directed to develop an appropriate technology for the digestion of organic solid wastes.
This resulted in the establishment of a process that has been patented, for treatment of organic solid wastes. The process has been designed to overcome the basic hurdles experienced in conventional anaerobic digesters such as scum formation, floating of waste, long retention time etc. Also, the separation of the acidification and the methanation phase can solve the problem of control of pH during the methanation phase of digestion.
The technology has been successfully tested in the field for different types of organic solid wastes for the generation of useful resources –biogas and manure. The promising results ensure the viability of the technology for wastes from varied sources. Due to its unique design and biphasic nature, the technology can treat any kind of organic waste within a short retention time of 7 days without use of mechanical mixing. Its uniqueness also lies in its following salient features.
Successfully tested for leafy waste, food waste, press mud, food-processing waste, tea waste, vegetable market waste, township waste etc. The technology can be designed in the modular form starting from 0.05 TPD to 10.0 TPD.
Technology Process Description
This process is a two stage process comprising of Acidification and Methanation. In the acidification phase, the organic content of the solid waste is leached out to make a high strength liquid by decomposition of the waste with intermittent sprinkling of water. In the methanation phase, this high strength leachate is treated in a high rate UASB (Up-flow Anaerobic Sludge Blanket) reactor to produce biogas.
There are six rectangular reactors (Acidification reactor) labelled as Acidification reactor (AR)-I to Acidification reactor-VI. The segregated waste collected from source will be shredded & charged in these six reactors into perforated bag placed in the reactors. AR-I will be charged on day 1 and AR-II on day 2 and so on till with AR-VI being fed on day 6. The waste will be charged into the reactors from the top of the acidification reactor. After charging the waste into acidification reactors, water will be poured in the reactor in the ratio of 1:2:: waste: water. Reactor will then be closed by putting lid on the top of the reactor. This is also necessary to maintain the anaerobic conditions inside the reactor. The water inside the reactor will be mixed intermittently with the help of a pump to maintain the homogeneous conditions inside the reactor. One pump will be used for two acidification reactors and hence there will be total three pumps for six acidification reactors.
On seventh day leachate from the acidification reactor will be collected in separate tank while residue will be removed with the help of motorized chain pulley supported on monorail with a lifting capacity of 2.0 tonne. The diagram 1 indicates the process as described so far. The volume of waste reduces to 40% after digestion and the digested sludge, after drying in the sun can be used as good quality manure.
Objective of the Project