Biochemical Oxygen Demand Reduction Research Articles

Interval Analysis of Volatile Solid (VS) and Biochemical Oxygen Demand (BOD) in Batch Anaerobic Fermentation of Selected Agrowaste

This study investigated the degradation of volatile solids (VS) and biochemical oxygen demand (BOD) during the anaerobic digestion of selected agro-waste, specifically cassava peels, maize husks, pig slurry, and the composite. The objective was to evaluate the biodegradability of these feedstocks, in line with their potential for biogas production. The Research was conducted at the National Centre for Energy Research and Development (NCERD) laboratory, University of Nigeria Nsukka (UNN). Batch reactors were used to conduct experiments over a period of 45 days. The digesters were operated under controlled conditions, and samples were analyzed at three (3) different points: 24 hours, peak of gas production (day 30), and at the end of the digestion (day 45). The results demonstrated that all the substrates exhibited a reduction in VS and BOD in the course of digestion. However, the most significant reduction in VS and BOD occurred around the peak of gas production. This entails that this period is critical for microbial activity and biogas yield. Corn husks had high initial VS and BOD values of 4.73±0.22 % and 92.80±3.26 mg/L respectively. However, that did not translate to higher biogas production compared with the composite that had initial values of 4.34±0.19 % and 88.00±5.50 mg/L respectively. By the end of the digestion, an average VS reduction of 65% and a BOD reduction of 70% were observed across all substrates, indicating a substantial degradation of organic material. Biogas production was better in the composite (72.580±4.53 %), an indication that higher VS and BOD do not automatically translate to higher gas yield. Thus, factors like multiple substrate interaction affect gas yield and process efficiency.

The Influence of Aloe Vera Biocoagulant and Mixing Time in Reducing Biological Oxygen Demand, Chemical Oxygen Demand and Total Suspended Solids Levels

Aloe vera is a plant with complex composition of carbohydrates, sugars, and mucilage, enabling it to bind particles in water and serve as a coagulant in the coagulation-flocculation process. This study aims to assess the impact of varying doses and rapid stirring times on the reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS) levels in liquid waste from pharmaceutical companies. The research involves two factors: (1) aloe vera concentration at three levels (20 mL/L, 40 mL/L, and 60 mL/L); (2) fast mixing time at three levels (20 minutes, 40 minutes, and 60 minutes), with each treatment repeated thrice. Levels of BOD, COD and TSS were measured post-treatment using a jar test tool. The results of the analysis showed that the optimal efficacy of the aloe vera coagulant occurred at a concentration of 40 mL/L for 40 minutes. At this optimal condition, the effectiveness of the aloe vera coagulant in reducing BOD, COD and TSS levels was 72.3%, 78.5%, and 65.3%, respectively. This indicates that the aloe vera coagulant can be effectively utilized in the treatment of pharmaceutical industrial wastewater to reduce BOD, COD and TSS levels

From Pollution to Preservation: Impacts of the Namami Gange Project on the Ganga River Ecosystem in the Varanasi Urban Area

The Namami Gange project was started by the Government of India, in 2014 as a mission to rejuvenate the Ganga River from acute pollution and environmental degradation, achingly throwing a plight on this holy waterway. This research paper explores the impact of the Namami Gange project on the holy river Ganga in Varanasi Urban Area, Uttar Pradesh. The study is based on a multi-disciplinary approach with the help of water quality monitoring, sources of pollution, and assessment of the measures followed under the Namami Gange Program. For monitoring the water quality, the parameters adopted in the present research are temperature, pH, conductivity, DO (dissolved oxygen), BOD (biochemical oxygen demand), FC (fecal coliform), and TC (total coliform), before and after the Namami Gange program implementation. Results show a visible improvement in water quality with major reductions in BOD and coliform levels, reflecting better oxygenation and reduced organic pollution. In this direction, the work pertaining to the establishment of STPs (Sewage Treatment Plants) and upgrading of existing infrastructure has been extremely crucial for mitigating the inflows of untreated sewage and industrial effluents into the river. The research also investigated the program's ecological effects on the restoration of aquatic habitats and biodiversity recolonization in a few river reaches. Public awareness campaigns and community participation programs were also completed with huge responses from the local population and pilgrims to enhance the sense of stewardship, which leads to greater sustainability and reduced pollution. The research, however, portrays that some of the lingering challenges pertain to continuous monitoring, STP maintenance, and non-point sources of pollution. More importantly, this would call for a holistic invasive management approach so that these positive outcomes as potentials of the Namami Gange program do not go astray. Overall, the paper provides valuable insights into the efficacy of large-scale environmental interventions and their potential to revive and preserve vital water resources like the Ganga River in Varanasi.

Industry restructuring and environmental performance – Decomposing the drivers of water pollution reduction in the Swedish pulp and paper industry, 1969-1989

This paper analyses the reduction of biochemical oxygen demand (BOD) emissions in the Swedish pulp and paper industry between 1969-1989. To that end, I have constructed pollution records for a large sample of Swedish chemical pulp producers and decomposed the observed changes in BOD emissions into (i) scale, (ii) technique, (iii) composition, and (iv) plant entry and (v) plant exit effects. In contrast to previous decomposition analyses of industrial pollution reduction, which have mainly emphasised the technique effect and/or compositional changes across surviving plants, this study finds that the majority of the pollution reduction was due to the exit of numerous (predominantly emission-intensive sulfite) plants, in combination with a continuous reallocation of production from such plants towards the surviving (predominantly sulfate) plants. The divergence in results can be attributed to the industry’s market structure, which is an important factor to consider when assessing the potential for successful pollution reduction.

Naturally derived organic biochar as an alternative to commercially activated carbon in the oxygen removal of seafood processing wastewater

AbstractBACKGROUNDThe seafood processing industries are tremendously increasing in numbers which eventually discharge a large quantity of wastewater with a high range of biochemical oxygen demand (BOD) and chemical oxygen demand (COD), directly into the aquatic environment. A high level of BOD and COD in wastewater pertains to a higher level of pollution which must be reduced to prevent hazardous impacts on ecosystems. The main objective of the research aimed to develop cost‐effective biochar and to remove BOD and COD from processing wastewater using two natural biomasses: water hyacinth and sugarcane bagasse.RESULTSNaOH‐treated and non‐treated biochar for both water hyacinth as well as sugarcane bagasse were prepared through the process of pyrolysis carried out at 600 °C with three different residence times of 30, 45 and 60 min. The wastewater was initially analyzed for BOD and COD levels. The results showed that among all the groups of biochars, the water hyacinth NaOH‐treated biochar pyrolyzed at 600 °C for 60 min exhibited significantly (P < 0.05) higher levels of reduction in BOD (86.6 ± 0.03%) and COD (94.3 ± 0.05%) at a residence time of 60 min in D2 (0.5 g (250 mL)−1). The maximum removal efficiency was observed for water hyacinth NaOH‐treated biochar pyrolyzed at 600 °C for 60 min.CONCLUSIONThe removal efficiencies of organic load revealed that the treated biochars exhibited a better reduction of nutrients. The biochar efficiencies when compared with those of activated carbon exhibited a higher removal level. The present research can be used to reduce BOD and COD levels in wastewater treatments. © 2024 Society of Chemical Industry (SCI).

Stormwater characterisation and modelling for Sungai Air Hitam in Selangor, Malaysia using model for urban stormwater improvement conceptualisation (music)

The aim of this study is to evaluate the current water quality status of one of the urban rivers in Malaysia, called Sungai Air Hitam. The river's water supply is not only unsuitable for the inhabitants but also hazardous to the aquatic species that depend on it. In order to simulate the water quality formulation of the river, the Model for Urban Stormwater Improvement Conceptualization (MUSIC) was used. The effects of various best management practices (BMPs) components have been examined to improve the river's water quality. This study also investigated different scenarios of the expected future changes in the land cover and the quality of the river. As the proportion of impervious surfaces increases, the urban hydrology cycle can be significantly altered, resulting in an increase in volumes and peak flows, and a decrease in storage, infiltration, and interception. The MUSIC results have shown significant reductions in biochemical oxygen demand (BOD), total suspended solids (TSS), total phosphorus (TP), and total nitrogen (TN) after introducing BMPs. It was also noticed that the prediction of pollutants falls within the acceptable range set by the Urban Stormwater Management Manual for Malaysia (MSMA) 2nd edition. For the land cover, it was found that the total reduction of BOD, TSS, TP, and TN for existing land use is 92.5 %, 94.5 %, 90.7 % and 91.9 %. Meanwhile, the total reduction in future land use is 81.6 % for BOD, 86.2 % for TSS, 80.9 % for TP and 80.8 % for TN. From the simulation results, it was observed that the application of BMPs has successfully reduced the observed mean BOD concentration from 92.38 mg/L (Class V) to 6.93 mg/L (Class IV) of the national water quality standards, NWQS, water quality index. As a result, the water quality index of the overall catchment has improved from Class IV to Class III (WQ1, WQ3, and WQ4) and from Class V to IV (WQ2) with the application of the BMPs. This assessment aims to raise awareness within the Sungai Air Hitam community regarding the importance of preserving river cleanliness and understanding the long-term environmental impact of water quality. These findings underscore the importance of an integrated system in managing urban water systems, which can offer valuable insight to the decision-makers.

Design and development of a pilot plant for the treatment of pharmaceutical wastewater containing molasses

Abstract The present work deals with the anaerobic treatment of molasses-bearing pharmaceutical wastewater using a specifically designed downflow anaerobic bioreactor (DFAB). The capacity of the designed DFAB was 1,000 L of adequate volume with necessary operational controls. Two types of anaerobic treatment, i.e. mesophilic and thermophilic treatments, were applied to the anaerobic biotransformation of wastewater under investigation. The efficiency of both treatments was compared in terms of reducing biochemical oxygen demand (BOD) and chemical oxygen demand (COD) load, as well as methane production. The anaerobic digestion process was carried out with the help of bacterial strains. The bacterial strains used in the mesophilic operation were acclimatised and utilised for the thermophilic treatment, which is a cost-effective and sustainable approach. A significant reduction in BOD and COD content of the wastewater was noticed after 10 days of retention time. Nearly 72–83% and 80–90% reduction in BOD values were recorded under mesophilic and thermophilic operations, respectively. Approximately 73–86% and 82–93% of COD content were reduced by mesophilic and thermophilic treatment, correspondingly. Methane production of 67 and 74% was achieved under mesophilic and thermophilic treatment, respectively. The designed DFAB showed remarkable treatment efficiency for wastewater and methane production.

Sustainable wastewater management in the brewing industry: Utilizing cellulose acetate membranes derived from brewers’ spent grain for enhanced treatment efficiency

Brewers’ spent grain (BSG), the primary by-product of the brewing industry, constitutes approximately 85.0% of the total by-products generated. BSG is known for its rich cellulose and non-cellulosic polysaccharide content, making it a valuable resource with significant potential for profitable recycling and reutilization. Given that the brewing sector is among the most substantial industrial consumers of water due to the water-intensive process of producing BSG, the effective management of wastewater in this industry is of paramount importance. This research focuses on investigating innovative wastewater management in the brewing sector. It employs the conversion of BSGs into a cellulose acetate membrane, thus enabling a physio-chemical treatment process utilizing the micro-filtration technique for wastewater treatment within the brewery industry. The results of this study demonstrate a substantial reduction in biochemical oxygen demand from the initial value of 16.65 mg/l (untreated) to 13.70 mg/l, 11.16 mg/l, 8.37 mg/l, 5.58 mg/l, and 3.14 mg/l after the first through fifth treatment cycles, respectively. Furthermore, the research indicates a high correlation with an R<sup>2 </sup>value of 0.999, affirming the viability and effectiveness of the treatment process. This is further substantiated by the results of chemical oxygen demand, total dissolved solids, total suspended solids, and hydrogen ion concentration analyses presented in this study. These findings not only validate the efficacy of utilizing BSG-derived cellulose acetate membranes but also emphasize the potential for revolutionizing wastewater treatment practices within the brewing industry. This research paves the way for sustainable, environmentally conscious strategies in industrial wastewater management, ensuring the optimal utilization of by-products while minimizing the environmental footprint of brewing operations.

EXPERIMENTAL INVESTIGATION AND ITS ANALYSIS IN TANNERY WASTEWATER USING MOVING BED BIOFILM REACTOR AND ACTIVATED SLUDGE PROCESS

The Tannery Industry produces a massive amount of toxic effluent which needs to be treated properly. It contains high organic matter, suspended solids, and chromium which in turn can cause environmental problems. This study provides valuable insights into the potential of Moving Bed Biofilm Reactor (MBBR) and Activated Sludge Process (ASP) for treating tannery wastewater. It also highlights the importance of proper wastewater treatment in the tannery industry to mitigate environmental impacts. The batch analysis was conducted to find out removal efficiencies for Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5), Sulphide (S2-), Ammonia (NH4), Nitrate (NO3). Kaldness K1 bio-media was used with a 50% filling ratio in the laboratory setup of the MBBR and aeration was provided to both setups. The results for the MBBR system showed chromium removal of 95.4% with the obtained reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), sulfide (S2-), and nitrate (NO3) 93.5%, 88.8%, 93.7%, and 97.09%, respectively. It indicates significant removal efficiencies for various pollutants in the tannery wastewater, suggesting the effectiveness of the MBBR system.

Biomass Fuel Production through Fermentation of Lysinibacillus sp. LC 556247 in Various Ratios of Palm Oil Mill Effluent and Empty Fruit Bunch

Biomass wastes originating from palm oil milling activities can be characterized by their high biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), and oil and grease content. The utilization of oil palm wastes such as palm oil mill effluent (POME) and empty fruit bunch (EFB) has great potential for a sustainable energy biomass pellet as it reduces the reliance on conventional materials for energy production. A mixture of POME and EFB in various ratios ranging between 7:3, 8:2, 9:1, and 10:0 was fermented in the presence of Lysinibacillus sp. LC 556247 for 120 h at 37 ± 2 °C and 180 rpm with the aim of elucidating the biodegradation of complex organic material in terms of BOD, COD, TSS, total organic carbon, inorganic carbon, and total carbon content. After fermentation, the mixtures were oven dried at 105 °C overnight and then subjected to calorific energy value (CEV) determination. The highest CEV of 20.26 MJ/kg was achieved for a ratio of 10:0 (slightly higher than the control experiment with the value of 18.67 MJ/kg), with maximum removal efficiencies of COD (12.19%), BOD (11.72%), TSS (93.94%), and oil reduction of 17.43%. The addition of EFB did not positively increase the CEV.

Towards Viable Eco-Friendly Local Treatment of Blackwater in Sparsely Populated Regions

The maintenance of people’s lifestyle against global climate change, exhaustion of groundwater, depletion of minerals, and water scarcity has instigated the recycling and reuse of water from unlikely sources. This situation has motivated researchers to develop effective technologies for treating wastewater, enabling its reuse. Water security has been ensured in myriad, highly populated regions through large-scale centralized treatment facilities. The development and implementation of small-scale, renewable-energy-based, decentralized, on-site treatment methodologies ensure water sustainability in rural areas, where centralized treatment facilities are impractical for application. This review article focuses on the recently reported low-cost purification techniques for recycling wastewater generated by single and community-based households in sparsely populated areas. Here we propose treatment technologies for efficient waste management that can be easily integrated in the upcoming years to the lavatories built under the Swachh Bharat Mission (SBM), a momentous cleanliness campaign that has been successfully implemented by the Government of India (GOI). Specifically, we suggest an electrochemical (EC) method to treat the supernatant of the Blackwater (BW) to produce purified non-potable water for reuse in diverse purposes. The EC technique does not require external chemicals for treatment and can be powered by sustainable technologies (like solar panels), thus reducing the treatment cost. Subsequently, vermicomposting, microwave, biogas, and phycoremediation methods are considered to treat the solid sludge to produce value-added products such as enriched organic fertilizer for agriculture and biofuel. The above methods also ensure the satisfactory reduction in Biochemical Oxygen Demand (BOD) (>85%) and Chemical Oxygen Demand (COD) (81–91%) and the complete removal of pathogens and other harmful pollutants. Finally, the novel treatment techniques discussed here are not only limited to rural areas of India but can be implemented in any rural area of the world.

Treatment of Sugarcane Vinasse Using Heterogeneous Photocatalysis with Zinc Oxide Nanoparticles

Vinasse is the main by-product of the ethanol industry; for each liter of ethanol, 13 to 18 L of vinasse is generated. Vinasse is composed of 93% water and 7% organic and inorganic solids and has an acidic pH and a high concentration of macro- and micronutrients used by plants, which is the reason for its widespread application in soil fertigation. However, over time, excessive direct discharge of vinasse into the soil causes damage, such as salinization and groundwater contamination. In this study, we used heterogeneous photocatalysis with zinc oxide nanoparticles (ZnO-NPs) to reduce chemical oxygen demand (COD) and biochemical oxygen demand (BOD) and as an antimicrobial treatment. ZnO-NPs were synthesized by the precipitation of zinc sulfate heptahydrate and sodium hydroxide, resulting in nanoparticles with a size of 21.6 ± 0.3 nm and an energy bandgap of 2.6 eV. Microscopic examinations revealed that Saccharomyces cerevisiae microorganisms are present in vinasse and that the minimum inhibitory concentration for the ZnO-NPs is 1.56 g/L. Photocatalysis with 40 mg/L of ZnO-NPs for 4 h of exposure to sunlight resulted in COD and BOD reduction efficacies of 17.1% and 71.7%, respectively. This study demonstrates the viability of using ZnO-NPs in vinasse treatment, contributing to sustainable applications and reducing the environmental impacts of fertigation.

Nanobubble ozonation for waterbody rejuvenation at different locations in India: A holistic and sustainable approach

In this study, four different sites of ponds at different time period were analysed to show to the effect of Nanobubble ozonation (NBO). NBO is one of novel technologies which is environmentally friendly only using air, ozone, and requiring virtually no chemicals. All the case studies have been performed in real time in different seasons and locations which gives the idea of importance of NBO for the treatment of water bodies with completely natural, environmentally sustainable, cost effective, and less time-consuming technology. Three case studies have been investigated in-situ (Site 1, 2, 4) and one ex-situ (site-3), which verify the efficacy of NBO in treating pond water. NBO treated water was determined to be in the standard limits, odour was eliminated, and water was cleaned enough to be consumed by the animals. The test results show that ozone nanobubble (NBO) in wastewater treatments achieved 85–99% reduction in total soluble solids (TSS), 80–90% reduction in biochemical oxygen demand (BOD), and 55% chemical oxygen demand (COD) reduction at site 3 and 82% COD reduction at site 4. Improved dissolved oxygen suitable for the living beings was achieved. Hence, this paper emphasizes the efficacy of NBO treatment to reclaim the water bodies and ecological restoration and to achieve the sustainable goals of clean water and environmental sustainability. DO level in all the ponds improved significantly after NBO treatment and showed the value of 14.5 mg/L when measured even after 50 h. Nanobubble gas dissolution system not only able to improve the dissolved oxygen up to supersaturation level but also able to retain it consistent more than 14–15 h. The vary reason for maintaining such consistency is the size of nanobubbles which is around <0.5 μm and NB doesn't follow the buoyancy, hence move in water in Brownian motion. NBG systems are future of our lakes and ponds rejuvenation and maintain the water quality.

Green walls as a novel wastewater treatment option for craft breweries

The fermentation industry has experienced significant growth as craft breweries and small wineries and cideries are enjoying increased popularity. These beverage manufacturers are also facing increased regulatory pressure to treat wastewater (WW) prior to discharge to the environment and municipal sewer systems. This research assesses the performance of a green wall system in treating brewery WW by measuring reductions in biochemical oxygen demand (BOD), turbidity, total solids and total nitrogen. The system includes a green wall column with a 35 L sump and a pump that continuously cycles wastewater at an average rate of 3 L/min through the green wall in a batch process. Experimental scenarios included a control with the pump cycling WW between the sump and an empty column and WW cycled through a media filled column, columns with media and biofilm, and the full system including media, plants and biofilm. After 24 h of treatment, the full system achieved 78%, 97% and 63% reductions of BOD, turbidity and total nitrogen, respectively. The net hydraulic residence time within the green wall column was 40 min over the 24 h treatment period. Although, the WW resided in the green wall columns for only 2.8% of the treatment period, the green wall accounted for 50%, 84%, and 94% of the reduction of BOD, turbidity, and total nitrogen. This green wall system has the potential to provide adequate treatment of brewery wastewater prior to discharge to a municipal sewer system or an onsite treatment system.

Wastewater effluents analysis from sustainable algae-based blue dyeing with phycocyanin

Sustainability in the textile industry is a challenge with an imminent need to be tackled. One approach can be focused on replacing fossil-based dyes with renewable and less polluting alternatives. In this sense, this study focuses on validating the suitability of an innovative natural-based blue dye, phycocyanin, sourced from Spirulina platensis microalgae. The laboratory-based experimental approach envisages the exhaustion dyeing of pre-mordanted cotton and bleached wool with phycocyanin-rich extract, representing the sustainable blue dye. The color characterization of naturally blue-dyed fabrics was performed via CIE Lab coordinates, depth of color by color stregth valures ( K/S), values of dye exhaustion, and colorfastness to laundering and light. The results indicate suitable dyeability with the natural blue dye, with process improvements a possibility. The main environmental character of this process was analyzed from the dyeing effluent characterization perspective. Measurements of chemical oxygen demand, biochemical oxygen demand, and metal content were performed on effluents resulting from dyeing processes with variable parameters, to analyze the influence of mordant use, process temperature, time, and pH. Findings indicate that the application of optimum dyeing process conditions results in the lowest oxygen demand values, suitable for further wastewater reuse, according to international industrial effluent limitations. The biological fungi wastewater treatment resulted in the reduction of biochemical oxygen demand and chemical oxygen demand values by around 80%, comparable with the industrial process, validating the sustainable character of using algae-based phycocyanin in the bath exhaustion dyeing process.

Isolation of a Marine Bacterium and Application of Its Bioflocculant in Wastewater Treatment

Bioflocculation has become the method of choice in wastewater treatment because of its effectiveness, environmental friendliness and innocuousness to humans. In this study, the bioflocculant-producing bacterium was isolated and its bioflocculant was used in wastewater treatment. The isolate was identified by 16S rRNA gene sequencing analysis. Its culture conditions (inoculum size, carbon and nitrogen sources, pH, temperature and time) were optimised using the one-factor-at-a-time assay. The cytotoxicity of the bioflocculant was assessed on human colorectal adenocarcinoma cells (Caco2) by tetrazolium-based colorimetric method. The ability of the bioflocculant to reduce biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in wastewater was evaluated using Jar test. The bacterium was identified as Bacillus subtilis CSM5 and the maximum flocculating activity of 92% was observed when fructose and urea were used as nutrients and the culture conditions were adjusted to 30 °C, pH 9, 160 rpm and 72 h of incubation. Caco2 exhibited 90% viability when the highest bioflocculant concentration of 200 µg/µL was used. The reduction of BOD and COD was achieved at 59 ± 3.1 and 75 ± 0.4%, respectively. In conclusion, B. subtilis CSM5 is a good candidate for bioflocculant production and its bioflocculant has good potential for use in wastewater treatment.

Real-time assessment of the Ganga river during pandemic COVID-19 and predictive data modeling by machine learning.

In this study, four water quality parameters were reviewed at 14 stations of river Ganga in pre-, during and post-lockdown and these parameters were modeled by using different machine learning algorithms. Various mathematical models were used for the computation of water quality parameters in pre-, during and post- lockdown period by using Central Pollution Control Board real-time data. Lockdown resulted in the reduction of Biochemical Oxygen Demand ranging from 55 to 92% with increased concentration of dissolved oxygen at few stations. pH was in range of 6.5–8.5 of during lockdown. Total coliform count declined during lockdown period at some stations. The modeling of oxygen saturation deficit showed supremacy of Thomas Mueller model (R2 = 0.75) during lockdown over Streeter Phelps (R2 = 0.57). Polynomial regression and Newton’s Divided Difference model predicted possible values of water quality parameters till 30th June, 2020 and 07th August, 2020, respectively. It was found that predicted and real values were close to each other. Genetic algorithm was used to optimize hyperparameters of algorithms like Support Vector Regression and Radical Basis Function Neural Network, which were then employed for prediction of all examined water quality metrics. Computed values from ANN model were found close to the experimental ones (R2 = 1). Support Vector Regression-Genetic Algorithm Hybrid proved to be very effective for accurate prediction of pH, Biochemical Oxygen Demand, Dissolved Oxygen and Total coliform count during lockdown.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13762-022-04423-1.

Experimental and optimization studies on phycoremediation of dairy wastewater and biomass production efficiency of Chlorella vulgaris isolated from Ganga River, Haridwar, India.

Dairy wastewaters (DWW) are rich in several pollutants, including high biochemical oxygen demand (BOD) and chemical oxygen demand (COD), and their unsafe disposal may cause damage to the environment. In this study, Chlorella vulgaris (identified as NIES:227 strain based on 28s rRNA sequencing) was isolated from the freshwater habitat of the Ganga River at Haridwar, India, and further tested for its efficacy in treating DWW. The phycoremediation experiments were conducted using three different DWW concentrations (0, 50, and 100%), operating temperatures (20, 25, and 30°C), and light intensities (2000, 3000, and 4000lx) using response surface methodology. Results showed that after 16days of experiments, a significant (P < 0.05) reduction in BOD (96.65%) and COD (87.50%) along with a maximum biomass production of 1.757g/L was achieved using 57.72% of dairy industry wastewater, 24.16°C of reactor temperature, and 3874.51lx of light intensity. The RSM models had coefficient of determination (R2) values above 0.9459 with a minimum difference between measured and predicted responses. Therefore, the findings of this study suggest that the isolated C. vulgaris can be effectively used to treat dairy wastewater along with significant production of algal biomass which can be further used for the generation of low-cost biofuel and other materials.

Floating Wetlands for Sustainable Drainage Wastewater Treatment

The preservation of water resources in modern urbanized society is a major concern. In this study, a floating constructed wetland (FWT) pilot plant was designed and constructed for the treatment of a polluted wastewater drain. A series of experiments were run continuously for a year in pilot-scale FWTs in a semi-arid area located in Egypt’s Delta. Four aquatic plant species (Eichhornia, Ceratophyllum, Pistia stratiotes, and Nymphaea lotus) were used to assess the performance of FWTs for pollutant removals, such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), electrical conductivity (EC), and total dissolved solids (TDS), from drainage wastewater to reuse the treated effluent in irrigation practices. The FWT systems were fed drainage tainted water on a weekly basis, and the concentrations and removal efficiency were assessed in the experiments. The average reduction in BOD, COD, TSS, TDS, TN, EC, and TP were 76–86%, 61–80%, 87–95%, 36.6–44.1%, 70–97%, 37–44%, and 83–96%, respectively. ANOVA with Post-HOC t-tests show that the Eichhornia, Pistia stratiotes, and Nymphaea lotus have the highest BOD and COD removal performance, whereas Pistia stratiotes and Nymphaea lotus have the highest TN and TP removal performance. In all cases, the Nymphaea lotus performed well in terms of pollutant removal. In addition, a design procedure for a FWT systems is presented. For wastewater treatment, FWT systems have proven to be a low-cost, long-term option.

Model Matematika Optimasi Multi-Objektif Penurunan Beban Limbah Biochemical Oxygen Demand pada Instalasi Pengolahan Air Limbah

The increase in community activities causes the amount of wastewater to increase. This wastewater comes from industrial production processes and from the community activities which are domestic wastewater. Domestic wastewater must be treated before being discharged to water sources because it contains pathogenic organisms. The place for treating domestic wastewater is Wastewater Treatment Plant (WWTP). The main purpose of WWTP is to degrade the Biochemical Oxygen Demand (BOD) and pathogenic organisms. This study develops a multi-objective optimization mathematical model for reducing the BOD load in the WWTP. This optimization model has three objective functions, namely maximizing the BOD load that is treated in the pond minimizing the difference between the BOD reduction efficiency value in the WWTP with the reference efficiency value and minimizing the power used by the aerator. The simulation results show that the maximum BOD load that can be treated in facultative ponds I and II is 1,589.688 Kg/day while for facultative ponds III and IV is 1,727.158 Kg/day. The efficiency value of reducing BOD load is influenced by the residence time variable, where the efficiency value of reducing the BOD load for facultative ponds I and II by 54% while for facultative ponds III and IV by 57%. The power used by the aerator is influenced by the treated BOD load variable, the aerator power in facultative ponds I and II is 49.67775 Kwh while in facultative ponds III and IV it is 53.97369 Kwh.