Research Projects

With rapid industrialization and urbanization, 300 × 10³ m³ of wastewater is generated annually worldwide, which led to elevated nitrogen (N) levels in aquatic environments. In the Indian context, approximately 2.9 billion of wastewater is discharged daily in river Ganga with over 60% of the N content originating from industrial sources. Biological nitrogen removal (BNR) has emerged as an effective and sustainable solution to address this issue. In BNR, while the theoretical C/N required for denitrification is 2.86 g COD/g N, studies showed that a higher C/N ratio is typically needed for effective N removal process. In contrast, various industrial wastewater effluents, tailwater from sewage treatment plants etc generally has C/N ratio below 3. This imbalance leads to inefficient N removal and higher operational cost due to requirement of aeration and exogenous carbon source for microbial activities. Anammox (anaerobic ammonium oxidation) bacteria can convert ammonium nitrogen directly into nitrogen gas (N2) using nitrite as an electron acceptor. On the other hand, comammox (complete ammonium oxidation) is a newly identified process (first reported in 2015) in which complete oxidation of NH4+-N to nitrate is carried out within a single organism, thereby streamlining the conventional N cycle and by passing the need for separate microbial population required for partial nitrification. While anammox has been well studied and implemented in various industrial processes (except in India), the emerging comammox process has not received similar attention in enrichment studies. Despite the advantages of comammox, in Indian context there is a noticeable gap with no study focused on its enrichment. This limits the potential for utilizing comammox in Indian industries with low C/N ratio effluents and underscores the need for its co-enrichment with anammox for efficient N removal. Therefore, the proposed project focuses on the co-enrichment of comammox and anammox bacteria in a single reactor system wherein comammox facilitates complete nitrification and also provide essential NO2--N for anammox bacteria while anammox reduces this NO2--N to N2 gas in anaerobic conditions, completing the N removal process. This research seeks to fill the existing gap focusing on their application in low C/N ratio wastewater treatment and will address the existing limitations through innovative reactor design, modified sponge biocarriers and signalling molecules for enhanced co-enrichment of Anammox and Comammox bacteria. Its outcomes could catalyse the adoption of advanced microbial technologies in India and set benchmarks for sustainable and efficient wastewater management practices globally. Moreover, the outcomes will be beneficial for various national initiatives like NMCG, National River Conservation Plan, and global frameworks such as UN SDGs 2030 (SDG 6), G20 action plan, by promoting sustainable wastewater treatment solutions to reduce pollution load in Indian rivers.