Review Article Online Published: 09 Mar 2026
Arch Appl Sci. 2026; 1(1): 43-46 doi: 10.5455/AAS.20251229101149 Microbial Bioremediation Strategies for Restoration of Urban Lakes in India: A Review Vijayakumar V, Bhagavanth Reddy G, Dr. Madhusudan Reddy. Abstract Urban lakes are vital ecological assets that provide water storage, biodiversity support, microclimate regulation, and recreational value. However, rapid urbanization, untreated wastewater discharge, and anthropogenic pressures have severely degraded their water quality. Microbial communities, due to their diverse metabolic capabilities, play a pivotal role in pollutant degradation, nutrient cycling, and ecosystem restoration. This review synthesizes current knowledge on urban lake pollution sources, the ecological significance of microbial communities, and biotechnological approaches—particularly the use of constructed wetlands (CWs) and floating treatment wetlands (FTWs)—for urban lake remediation. Case studies and recent advances in microbial bioremediation are discussed, with emphasis on integrating nature-based solutions into urban water management policies in India. Key words: Urban lakes, microbial remediation, constructed wetlands, floating treatment wetlands, eutrophication, wastewater treatment, India, nature-based solutions   ARTICLE TOOLS Abstract PDF Fulltext How to cite this article Citation Tools Related Records   Articles by Vijayakumar V Articles by Bhagavanth Reddy G Articles by Dr. Madhusudan Reddy on Google on Google Scholar

Introduction

Urban lakes are integral components of city landscapes in India, providing essential ecosystem services such as water storage, biodiversity support, microclimate regulation, and cultural value. Rapid urbanization, unplanned landuse changes, and discharge of untreated domestic and industrial effluents have led to widespread degradation.Urban lakes such as Hussain Sagar (Hyderabad), Ulsoor Lake (Bengaluru), and Rabindra Sarobar (Kolkata) have experienced severe anthropogenic stress due to sewage inflows, industrial effluents, and solid waste dumping [1]. Domestic wastewater contributes nearly 80% of the nutrient load in Indian urban lakes, accelerating eutrophication and biodiversity loss [2].Conventional physicochemical remediation methods such as chemical precipitation, aeration, and dredging are often costly and unsustainable [3]. Microbialbased approaches offer ecofriendly and selfsustaining alternatives [4].Microbialbased restoration strategies directly advance SDG 6 (Clean Water and Sanitation) by improving urban surface water quality and enabling decentralized wastewater treatment.

Sources of pollution in Urban Lakes

Urban lakes are subjected to multiple pollution sources. Domestic sewage contributes high organic matter and nutrient loads, accelerating eutrophication [5] Table 1. Untreated industrial effluents introduce heavy metals and toxic compounds [6]. Urban runoff transports sediments, pesticides, and hydrocarbons into lakes [7]. Improper solid waste dumping leads to anaerobic conditions and methane release [8].

Role of microbial communities in Urban Lake ecosystems Microbes act as primary decomposers and biogeochemical regulators [9]. Heterotrophic bacteria degrade organic carbon, reducing biological oxygen demand (BOD) and chemical oxygen demand (COD) [10]. Nitrifying bacteria such as Nitrosomonas and Nitrobacter oxidize ammonia to nitrate [11]. Denitrifying bacteria, including Pseudomonas and Bacillus, remove nitrates via gaseous nitrogen release [12]. Phosphatesolubilizing bacteria mitigate phosphorus availability [13]. Hydrocarbonoclastic bacteria degrade oil pollutants [14]. Archaea contribute to nitrogen cycling and anaerobic sediment processes [15].

Microbial bioremediation strategies for Urban Lakes Constructed wetlands (CWs) Constructed wetlands are engineered systems mimicking natural wetlands to treat wastewater [16]. Microbial biofilms on plant roots degrade organic pollutants and transform nitrogen compounds through nitrification–denitrification [17,18] Figure 1. Surface flow and subsurface flow systems are commonly employed [19]. In Varthur Lake, Karnataka, CW implementation achieved 78% COD and 69% total nitrogen reduction within five months [20].

Floating treatment wetlands (FTWs) FTWs are buoyant systems planted with macrophytes whose roots support microbial colonization [22]. They enhance dissolved oxygen, reduce turbidity, and remove nutrients [23].

Bioaugmentation and biostimulation

Bioaugmentation involves introducing pollutantspecific microbes such as Pseudomonas putida for hydrocarbon degradation [24] Figure 2. Biostimulation enhances native microbial activity through nutrient amendments [25,26].

Results: case studies from India In Hussain Sagar Lake, installation of FTWs resulted in 40% reduction in total nitrogen and phosphorus within 6 months [27]. Ulsoor Lake restoration using CWs enriched with microbial consortia achieved 65% reduction in BOD [16]. Rabindra Sarobar restoration using CWs and aeration increased dissolved oxygen and reduced total nitrogen over 8 months.

Urban lake restoration faces challenges, including variable pollutant loads, seasonal microbial shifts, and space constraints. Integration of IoTbased monitoring, metagenomicsguided interventions, and smart city governance frameworks can enhance restoration efficiency [28] Table 2.

Knowledge gaps and research needs

Longterm microbial community dynamics remain underresearched. Limited data exist on microbial responses to emerging pollutants such as microplastics and pharmaceuticals. Integration of molecular tools with physicochemical monitoring is needed.

Microbialbased restoration strategies integrated with constructed wetlands and floating treatment wetlands represent scalable, costeffective naturebased solutions for rehabilitating urban lakes in India. Advances in microbial monitoring and governance integration are essential for sustainable urban water management.

References