ANNOUNCEMENTS
Over the past 2 years, the sludge recycling has come into urgent need in Nagpur due to the upcoming of STPs. The total quantity of sewage sludge produced annually is estimated to be 54 Tonnes per day increasingly in Nagpur in 2021. Currently, the sewage sludge management is a huge challenge in India. The sludge production is estimated to be 1200 Tonnes per day and potential of 4000 Tonnes per day. The nutrient potential of available sewage in India is more than 350,000 tonnes of Nitrogen, 150,000 of Phosphorus and 200,000 Tonnes of Potassium per year(Juwarkar et. al., 1991).
With the upcoming new technologies to treat the wastewater, the quality of final effluent has also increased but led to an increase in the quantity of produced sludge. The disposal of the sludge after the treatment of wastewater still does not have standard solutions. There is lack of literature review on extended aeration sludge and its appropriate disposal. To classify the secondary sludge according to USEPA, the assessment of effluent characteristics is also necessary. The USEPA has laid down the guidelines for classification of sludge (Class A or Class B) on the basis of the level of pathogens present in sludge. The alternatives to reduce the pathogen for better disposal is also mentioned in the USEPA manual. If pathogens (Salmonella sp. bacteria, enteric viruses, and viable helminth ova) are below detectable levels, the biosolids meet the Class A designation. Biosolids are classified as Class B if pathogens are detected but are reduced to levels below the threat to public health and the environment until actions are taken to prevent exposure to the biosolids after their use or disposal. (40 CFR Part 257 et al. 1993).
The solid by-products after treating the wastewater are termed as “Sludge” now as “Biosolids”. Biosolids consist of biological solids and their chemical and biological characteristics need to be emphasized in order to make them productive. In developing countries like India, the final disposal of Sludge is neglected or sludge management is not considered as it represents a very small fraction of treated water. The management is quite complex and requires a high amount of operating cost of STP. The classification of Sludge is given by USEPA on the basis of which the disposal or further treatment can be decided. The effluent and sludge output assessment is the primary aim of the study to make disposal and sludge management easy.
Keywords: Sewage Treated water reuse, Nagpur Municipal Corporation, Sewage treatment plant, Sludge, Process stability, Extended aeration SBR.
