Assessment and Management of Hebbal Lake, Bangalore: Water Quality, Pollution, and Restoration Strategies

Development of a technique for rapid field estimation of biochemical oxygen demand (BOD) is necessary for cost-effective monitoring and management of urban lakes. While several studies reported the usefulness of laboratory tryptophan-like fluorescence technique in predicting 5-day BOD (BOD₅) of wastewater and leachates, little is known about the predictability of field chlorophyll fluorescence measurements for BOD of urban lake waters that are constantly exposed to the mixture of chemical compounds. This study was conducted to develop a numeric relationship between chlorophyll a fluorescence and BOD for a eutrophic urban lake that is widely representative of lake water conditions in the subtropical southern USA. From October 2012 to September 2013, in situ measurements at the studied lake were made every 2 weeks on chlorophyll a fluorescence and other water quality parameters including water temperature, pH, dissolved oxygen, and specific conductivity. Water samples were taken for 5-day BOD and 10-day BOD (BOD₁₀) analysis with and without incubation. The results showed a clear seasonal trend of both BOD measurements being high during the summer and low during the winter. There was a linear, positive relationship between chlorophyll a fluorescence and BOD, and the relationship appeared to be stronger with the 10-day BOD (r(2) = 0.83) than with the 5-day BOD (r(2) = 0.76). BOD dropped each day with declining chlorophyll a fluorescence, suggesting that die-off of phytoplankton has been the main consumption of oxygen in the studied lake. Ambient conditions such as rainfall and water temperature may have partially affected BOD variation.

Domestic wastewater in the culinary area is waste water produced from several restaurants. The problem of liquid waste needs to get serious attention, because it has complex characteristics and the remaining results of these activities can cause the volume of wastewater with a high contaminant load that flows continuously over a long period of time. One way to manage the environment is through physical processing, namely by pre-treatment of sedimentation and biological treatment by biofilter anaerobic processes. Anaerobic biofilter is a biological treatment, which uses media as a place to grow and develop microorganisms, with no oxygen in the reactor. The parameters in liquid waste processing consist of three, namely physical parameters, chemical parameters and biological parameters. In the method of combating liquid waste here uses chemical parameters, namely BOD and TSS. Where BOD ( Biochemical Oxygen Demand ) is the number of milligrams of oxygen needed by aerobic microbes to decompose karon organic matter in 1 L of water for 5 days at a temperature of 20EsC ± 1EsC. Whereas for TSS ( Total Suspended Solid ) as the residue from total solids held by a filter with a particle size of maximum 2I¼m or greater than the size of colloidal particles, which include TSS are mud, clay, metal oxides, sulfides, algae, bacteria, and fungi . The aim of this research is that the liquid waste from the activity can be reused as clean water by anaerobic biofilter method using BOD and TSS parameters. The variables used are operational time. Reactor I and reactor II contain media arranged from the bottom up, namely rock fragments, gravel, shells and gauze. The operational time variations used are 0 hours as t0 or the first time the waste exits the reactor, and the time is 2 hours, 4 hours, 6 hours, and 8 hours is a periodic observation of operational time. The results showed that anaerobic biofilter has the ability to reduce the concentration of BOD ( Biological Oxygen Demand ) and TSS ( Total Suspended Solid ). Based on the Regulation of the Minister of Environment and Forestry of the Republic of Indonesia Number P.68 / Menlhk / Setjen / Kum.1 / 8/2016 concerning Domestic Waste Water Quality Standards, the characteristics of wastewater are obtained before treatment (pre treatment) which is 28- 31 ° C; pH 9,3-10; BOD 30 mg / L; and TSS 29 mg / L. Decreasing the initial state in reactor I for BOD is 25 mg / L. Whereas for the decrease in TSS is 16 mg / L. The results showed that anaerobic biofilter with pumice, gravel and clam shell media had the ability to reduce BOD and TSS concentrations significantly. The percentage decrease in concentration in reactor I was greater than that of reactor II, with an operational time of 6 hours for BOD allowance of 73,54%. While the operational time of 8 hours for TSS is 81,39%.

The decline in river air quality is characterized by a decline in air quality parameters, namely physical, chemical and microbiological parameters. Preliminary studies revealed that the physical and chemical parameters of TSS, BOD were respectively 52 mg/L, 57 mg/L, the test results were not in accordance with Government Regulation no. 22 of 2021 concerning Implementation of Environmental Protection and Management. The aim of this research is to determine the quality of river water based on physical and chemical parameters, namely Total Suspended Solid (TSS), Total Dissolved Solid (TDS), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Dissolved Oxygen (DO), water potential hydrogen (pH) in Karanganyar Regency. This research method is quantitative descriptive using laboratory tests, with samples from 6 rivers in each sub-watershed. The sampling technique uses Integrated Sampling by carrying out laboratory testing. Data analysis uses air quality measurements using the pollutant index method. The parameters tested are physical parameters, namely TSS, TDS and chemical parameters, namely COD, BOD, DO and pH. The research results show that the TSS parameters exceed the quality standards, TDS corresponds to the quality standards, COD exceeds the quality standards, BOD exceeds the quality standards, DO corresponds to the quality standards, pH does not comply with the quality standards. The conclusions in this research are that the Jlamprang River sub-watershed of Kudus is 1.99 (lightly polluted), the Bagor River is sub-watershed of Jlantah 2.31 (lightly polluted), the Gembong River is sub-watershed of Samin 6.94 (moderately polluted), the Kumpul River is sub-watershed of Mungkung 2 .74 (lightly polluted), Kendat River, Kenatan sub-watershed, 2.67 (lightly polluted), Pepe River, Pepe sub-watershed, 2.14 (lightly polluted). The suggestion for the Karanganyar District Government is to monitor river water quality regularly Keywords: Chemical Oxygen Demand, Biological Oxygen Demand, Dissolved Oxygen.

Sewage sludge is an important soil conditioner, and source of nutrients with a potential for use in agriculture. However, such benefit needs to be weighed against the risks due to the presence of heavy metals, and other substances that may endanger human health, plants, soil and the ecosystem. This research had the objective of evaluating the agricultural potential of sewage sludge together with the risks that may be present in use. Samples of sewage sludge from seven wastewater treatment plants in Eswatini were analyzed for selected physical and chemical parameters, and heavy metal concentrations using commonly established laboratory procedures. The analysis results indicated that, sludge samples exhibited high organic matter content, cation exchange capacity, macro nutrients such as nitrogen and phosphorus and micro nutrients (trace metal elements) needed for plant growth. Anaerobically digested sludge samples showed higher carbon to nitrogen ratio because of biomass loss in the form of methane and carbon dioxide. The heavy metal concentrations are all within safe limits except the sludge from Matsapha area that had levels of chromium, and nickel above regulatory limits. With respect to their heavy metal contents, most of the sludge samples would qualify as Class A sludge ready to be used as organic fertilizer for agriculture without regular monitoring of heavy metals in the soil to which they are applied. The study results indicated the importance of sewage sludge for their agricultural potential through supplementation of both micro and macro nutrients needed for plant growth, for improving the soil properties such as water holding capacity and permeability, through the increase of organic matter content, and retention of nutrients due to the high cation exchange capacity. All these benefits are realized with sewage sludge being a lower cost alternative to commercial fertilizers. Moreover, the low concentration of heavy metals present in the sludge presents lower risk that may arise in the course of utilizing the sludge as agricultural supplement. Key words: Agriculture, fertilizer, heavy metals, nutrient, sewage, sludge, nitrogen, phosphorous

The present study investigates groundwater quality in terms of heavy metals level and microbial contamination as well as the impact of bleaching powder on microbial load of groundwater samples in close proximity to a surface water body inside selected areas of Ibadan Nigeria. To do so, it collects nine water samples from three boreholes and six hand-dug wells from six locations, namely Eleyele, Wofun-Olodo, Oluyole Industrial Estate, Ogunpa, Olorunsogo, and Ojoo, keeping them in 750 mL plastic bottles. The samples are then divided by two, giving a total amount of 18 samples, with 3 and 6 duplicates apiece being treated with bleaching powder and the rest remaining untreated. Both sample sets have been analysed for water quality parameters such as pH, biochemical oxygen demand, and chemical oxygen demand, assessed using standard methods. The coliform count has been determined, using the pour plate method while heavy metal has been set by means of Atomic Absorption Spectrophotometer (AAS) after nitric acid digestion. Results show that the pH ranges within 6.0-6.5, BOD within 1.67-4.33mg of O2/L, and COD within 2.93-9.43, while heavy metal concentration is from 0.013 to 0.047 mg/L for lead, ND to 0.023 mg/L for chromium, and ND to 0.010 for cadmium. What is more, the coliform count in the samples is between 0.00 and 913.33 CFU/mL. Most of the samples exceed the WHO limits for heavy metals in drinking water, having significant levels of microbial contamination. Bleaching powder treatment alleviated the level of pollution to varying degrees; therefore, constant monitoring of groundwater source and treatment before drinking is of utmost importance.

Limnological analysis of an urban polluted lake in Bangalore city in India

Introduction: Increasing volume of medical wastewater presents a significant challenge for environmental management, particularly in healthcare facilities such as the Blood Donor Unit (UDD) of the Indonesian Red Cross (PMI). Inadequate wastewater treatment can lead to environmental pollution and pose serious public health risks. This study aimed to evaluate the performance of a Wastewater Treatment Plant (WWTP) at the UDD PMI in the Cilacap Regency by analyzing key physical, chemical, and biological parameters.Methods: This study employed a descriptive, quantitative approach. Wastewater samples were collected from the WWTP outlet using random sampling. The samples were placed in sterile bottles, stored at low temperatures, and analyzed at Cilacap Environmental Agency Laboratory using standardized methods for water and wastewater examination (APHA, 2017). The parameters tested included pH, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), oil and grease, ammonia, and total coliform.Results: The physical parameter (TSS: 18 mg/L) and chemical parameters (pH: 8.0; BOD: 7 mg/L; COD: 10 mg/L; oil and grease: 1.9 mg/L; ammonia: <0.01 mg/L) were all within acceptable regulatory limits. However, the biological parameter of total coliforms exceeded the permissible threshold (>24,000 MPN/100 mL), indicating possible fecal contamination. This result highlights a significant risk to both public health and the environment.Conclusion: Although WWTP are equipped with standard treatment units, their disinfection process is insufficient, posing the potential risk of waterborne disease transmission (e.g., cholera). Therefore, immediate improvements in disinfection systems are recommended.

Impact of sandy soil physico-chemical properties towards urban lakes eutrophication and inorganic pollutant status

Anthropogenic activities generate pollutants that are often discharged, untreated, into bodies of water. The drainage system, known as the Caleta in Ciudad del Carmen, Mexico, is surrounded by an urban area and receives immense amounts of industrial and sewage discharge. Physicochemical analyses were conducted for the water and sediment samples taken along this drainage system to understand its hydrological dynamic and pollutant load. The drainage channel communicates with Terminos Lagoon, a Natural Protected Area, and the Gulf of Mexico. Water and sediment samples were taken at fifteen stations along the drainage channel during the three local seasons: northwinds (January); dry (May); and rainy (October). Physicochemical parameters (pH, temperature, salinity, dissolved oxygen, and total dissolved solids), as well as biological oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS) were measured in the water samples. Heavy metals concentrations (Fe, Cr, Cu, Zn, Cd and Pb) were quantified in the sediment samples. No differences were observed in the physicochemical parameters between sample stations, although differences (P < 0.05) were observed between seasons. Dissolved oxygen levels at all stations and in all seasons were near or below hypoxia levels (< 2.0 mg/l). Biological oxygen demand and COD were highest during the rainy season, particularly near industrial effluent discharges. Heavy metals concentrations varied spatially, with higher levels nearest the drainage outlet and lower levels further inland. Lead and iron levels were extremely high, and all heavy metals concentrations far exceeded legal limits. The Caleta is clearly heavily impacted by discharge from the surrounding urban area containing pollutants generated by anthropogenic www.witpress.com, ISSN 1743-3541 (on-line) WIT Transactions on Ecology and The Environment, Vol 200, © 2015 WIT Press Water and Society III 295 doi:10.2495/WS150251 activities. Any possible recovery of this drainage ecosystem will be contingent on treating and controlling any discharges into it.

The Chaktai Channel is an important Channel connecting the Karnaphuli River, located in the Chattogram in the Chattogram City Corporation Area. Chaktai Channel is situated in a strategically significant sector of Chattogram City, close to numerous other enterprises. The Karnaphuli River receives the industrial wastewater dumped into it and flows down the channel. Samples were taken at several locations along the Chaktai Channel, which is connected to the river, to ascertain the quality of the water entering the Karnaphuli River. The samples were taken from the channel’s most contaminated section, which is home to several enterprises. The study was conducted between the area of Chaktai Bridge (Location 1), Ashraf Ali Road (Location 2), Fishery ghat area (Location 3), Chaktai Ghat (Location 4) and Asadganj (Location 5), where industries discharge their untreated toxic wastewater. It involved the determination of physical and chemical parameters of surface water at different points. Physical parameters are colour, odour, temperature, turbidity, pH, and Electrical Conductivity (EC), and chemical parameters are Total Solids (TS), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Dissolved Oxygen (DO), Total Alkalinity, Total hardness etc. The main objective of this study is to assess the water quality and parameters of Chaktai Channel in terms of the Water Quality Index (WQI) and the following order of water quality index (WQI) is Location 5 (Asadganj) > Location 1(Chaktai bridge) > Location 4(Chaktai ghat) > Location 2(Ashraf Ali Road) > Location 3(Fishery Ghat). The water quality index is higher at the channel’s north side or upper stream near the industrial area. During the study period, the temperature fluctuated from 26.0°C to 31.5°C, while the water temperature ranged from 5.5 to 8.0. From L1 to L5 (L4L5>L2>L1), as well as the overall hardness of the sample (L3>L2>L5>L4>L1). Samples 1 and 2’s COD, DO, and BOD are within the limit, whereas samples 3 through 5 are above the limit.

Urban and peri-urban lakes are increasingly threatened by water quality degradation due to rising anthropogenic pressures and environmental variability. This study proposes an integrated framework that combines multi-source data and machine learning to estimate and monitor three key water quality parameters: turbidity, total dissolved solids (TDS), and biological oxygen demand (BOD). Field measurements from three lakes in West Bengal, India, Rabindra Sarovar, Mirikh Lake, and Hanuman Ghat Lake, were combined with Landsat-8 satellite imagery, meteorological data, and land use information. Three modeling scenarios were developed: (i) using only remote sensing indices, (ii) combining remote sensing indices with meteorological variables, and (iii) integrating remote sensing indices, meteorological data, and land use features. Principal component analysis (PCA) was used to reduce dimensionality and redundancy. Machine learning models, namely, XGBoost, Decision Tree, and Ridge Regression, were trained and evaluated using R2 and RMSE (Root Mean Square Error) metrics. The third scenario outperformed the others, with Ridge Regression achieving the highest accuracy for BOD prediction (R2 = 0.99). Spatiotemporal patterns revealed persistently high BOD levels along urban lake fringes and post-monsoon spikes in turbidity and TDS, especially in agriculturally influenced zones. These patterns were closely linked to land use practices, rainfall-driven runoff, and point-source pollution. This study underscores the effectiveness of remote sensing and machine learning as scalable tools for real-time water quality monitoring, promoting sustainability through informed lake management strategies in India.

ABSTRACT: Fecal contamination and organic pollution of an agricultural drainage in northeast Indiana was high. Bacterial counts (total coliform, TC; fecal coliform, FC; and fecal streptococcus, FS) and biochemical oxygen demand (BOD) were used to assess waste concentrations. Coliform counts indicated that sections of the drainage receiving septic effluent had waste concentrations far in excess of public health standards (mean FC = 550,000/100 ml). Areas of drainage remote from septic tank pollution were found to occasionally meet federal public health standards for whole body contact recreation but generally these areas had twice the allowable limit of 200 FC/100 ml. Bacterial contamination was highest during runoff events when the median values for TC, FC, and FS were 5, 3, and 17 times greater, respectively, than the median values during low stream discharge. Surface flows carried contaminants from unconfined livestock operations and fecally contaminated sediment was transported by high waters. During one runoff event a BOD loading of 36.7 kg/km2 was recorded and the peak BOD concentration observed was 16 mg/l. A discharge of liquid manure from a confined livestock operation caused a major fish kill. Pollution from septic tanks and unconfined livestock is greatest at high stream discharge when dilution reduces the impact on aquatic life.

Groundwater contamination near automobile workshops is a growing environmental concern due to the leaching of heavy metals and other pollutants into the soil and water sources. This study aims to assess the physicochemical and heavy metal characteristics of groundwater in the Central Business District of Oxbow Lake, Swali, Bayelsa State, before and after treatment. Physicochemical parameters, including pH, total dissolved solids (TDS), electrical conductivity, temperature, chemical oxygen demand (COD), biological oxygen demand (BOD), and heavy metal concentrations (Fe, Cu, Pb, Ni, and Mn), were analyzed before and after treatment. The results show that pH increased from 6.80 ± 0.02 to 7.70 ± 0.02, remaining within the permissible limits of 6.5–8.5 (WHO) and 6.6–9.0 (NSDWQ). Total dissolved solids (TDS) ranged from 122 ± 1.5 to 141 ± 1.5 mg/L, and conductivity reduced from 238 ± 2.0 to 221 ± 2.0 µS/cm, both well below the regulatory limits. Temperature varied marginally from 27.4 ± 0.1°C to 27.8 ± 0.1°C. Chemical oxygen demand (COD) and biological oxygen demand (BOD) increased from 0.58 to 1.06 mg/L and 0.45 ± 0.01 to 0.71 ± 0.01 mg/L, respectively. Heavy metal analysis revealed that Iron concentrations were significantly reduced after treatment, from 0.36 ± 0.01 mg/L to below the detection limit (&lt;0.001 mg/L) slightly exceeded the WHO and NSDWQ limit of 0.3 mg/L, while manganese (0.14–0.42 mg/L) exceeding the WHO guideline. Copper concentrations dropped below the detection limit (&lt;0.001 mg/L) after treatment, from an initial 0.50 ± 0.01 mg/L. Both nickel and lead were below the detection limit (&lt;0.001 mg/L) before and after treatment, indicating zero contamination from these metals. Despite the low concentration observed for the various parameters, continuous monitoring and control measures is recommended.

This study evaluates the physicochemical characteristics of stormwater runoff from a cement manufacturing plant in Kogi State, Nigeria, during the rainy season (June to August 2024). The objective was to assess the environmental impact of cement production processes on stormwater quality. The parameters analyzed include pH, electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), chloride and sulphate ions, and heavy metal concentrations. Results revealed pH values ranging from 6.52 to 11.50, with alkaline runoff exceeding regulatory limits during peak production activities. The TSS levels (288 ± 2.65 to 420 ± 5.57 mg/L) and TDS concentrations (200 ± 2.74 to 312 ± 3.21 mg/L) were within the permissible limits of the National Environmental Standards and Regulations Enforcement Agency (NESREA) of Nigeria. The BOD and COD values occasionally exceeded thresholds, indicating organic pollution during certain conditions. Sulphate levels were significantly elevated (up to 540 mg/L), suggesting atmospheric deposition of industrial emissions. Heavy metal analysis revealed variable concentrations of Fe, Zn, Cu, Pb, and Mn ions, with some samples exceeding NESREA limits for Fe and Cu. The findings underscore the need for effective stormwater management strategies in cement plants to mitigate environmental impacts and ecological risks associated with industrial stormwater discharges in Nigeria, and to ensure compliance with regulatory standards.

Response of 12 urban lakes with different trophic states in Beijing to variations of meteorological factors was studied in this research. Monthly water quality parameters, including total nitrogen (TN), total phosphorus (TP), chlorophyll a, chemical oxygen demand (COD), biological oxygen demand (BOD), dissolved oxygen, and water temperature, were analyzed from 2009 to 2011. Results indicated that TN in the urban lakes did not exhibit significant response to meteorological variations owing to relatively lower TN concentration in the urban soil. For the highly eutrophic lakes, TP, chlorophyll a, COD, and BOD were positively correlated with precipitation, and negatively correlated with wind speed (p < 0.05). Chlorophyll a showed significant positive correlation with TP and temperature. Moreover, the abrupt increase of TP occurred in spring, which was associated with higher temperature induced internal phosphorus loading. On average, temperature/precipitation and wind speed/sunshine duration contributed to 10.7–43.8 and 8.3–19.2 % of the variations in water quality. In contrast, lakes with mesotrophication/light eutrophication did not show significant sensitivity to meteorological variations owing to their better buffer capacity and regulation effect of algae growth. Beijing is undergoing increased temperature and heavy rainfall frequency as well as decreased wind speed during the past five decades; the above results infer that water quality of most urban lakes of Beijing is becoming worse under this climate change trend. This study suggested that urban lakes with different trophic states will respond differently to global climate change, and highly eutrophic lakes might face big challenges of water quality deterioration and algae bloom.