Biochemical Oxygen Demand Reduction Research Articles

Bioremediation potential of newly isolated Bacillus albus strain VKDS9 for decolourization and detoxification of biomethanated distillery effluent and its metabolites characterization for environmental sustainability

In India, the environment friendly and sustainable management of colored effluents emanating from alcohol-producing distilleries has become a serious environmental concern. The current study aimed to examine the efficiency of ligninolytic enzyme-producing bacterial strain isolated from ameliorated distillery sludge by enrichment method for its bioremediation and detoxification potential of biomethanated distillery effluent (BMDE). Out of nineteen bacterial isolates isolated from distillery sludge, one strain VKDS9, having higher ability towards the removal of effluent’s color, was identified as Bacillus albus by 16S rRNA analysis. The bacterium showed significant decolourization of effluent up to 83% with subsequent reduction of biochemical oxygen demand (3261 mg/L), chemical oxygen demand (7870.5 mg/L), and other physico-chemical parameters including metallic and non-metallic elements in the presence of glucose (1% w/v) and peptone (0.5% w/v) at optimal temperature 37 °C, pH 8.0, and 180 rpm within 144 h. Further, biodegradation of effluent was confirmed by high performance liquid chromatography analysis that showed appearance/disappearance and reduction of several peaks. Moreover, GC–MS​ analysis of bacterial treated effluent displayed the disappearance of several chemical contaminants and formation of new metabolites which were formed as end products of biodegraded effluent. Furthermore, phytotoxicity of treated and untreated BMDE was evaluated using Cicer arientinum L. seeds revealed the biodetoxification of BMDE after treatment by B. albus strain VKDS9. This study concluded that B. albus strain VKDS9 can be used as an efficient biotechnological tool for remediation of distillery effluent for its harmless dumping into the environment towards sustainable development. • Novel ligninolytic enzyme producing Bacillus albus strain VKDS9 was isolated. • Significant pollutant load along with color removal was achieved by strain VKDS9. • Phytotoxicity​ assessment showed toxicity reduction in treated distillery effluent. • Strain VKDS9 can be used as a promising tool for remediation of distillery effluent.

Sustainable cleaner production technologies and treatment of segregated effluent streams with recovery of quality salt, chromium & water

Conventional process and treatment system adopted by Indian and Global Tanneries consist of Segregation of Spent Chrome Stream and discharge of supernatant for combined treatment along with effluent from all sectional operations starting from soaking to finishing, Conventional physiochemical and biological treatment for reduction of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), etc., Ultra-filtration and Reverse Osmosis (RO) system for recovery of water and Multiple Effect Evaporator (MEE) for the evaporation of RO reject stream and generation of mixed salt in case of Zero Liquid Discharge (ZLD) system and Storage of mixed salt recovered from the MEE system for which no viable disposal system is found. Establishment of treatment system for the mixed stream results in poor performance of biological treatment units, increases the Operation & Maintenance (O&M) cost and accumulation of recovered mixed salt in case of ZLD system. It is estimated that, more than 8-10 tones of mixed salt is generated during the treatment of 1.0 MLD effluent under ZLD system. To address this serious environmental problem, an innovative approach of segregation of saline streams such as soak liquor and chrome liquor are planned to be collected separately with the feasibility of recovering reusable quality salt and chromium in the form cake for regeneration and use in the form of Basic Chromium Sulphate (BCS) by the tanneries. This innovative treatment concept has been developed and is being implemented in many Common Effluent Treatment Plants (CETPs) in India. This will become the first of its kind in Global Leather World. This developmental scheme is in accordance with the guidelines and recommendations of UNIDO in terms of sustainability of ZLD system for leather sector. The technological developments on cleaner productions, centralized chrome recovery reuse system, segregation of saline soak water for separate treatment with recovery of water and quality salt are dealt in this technical paper.

A Synergistic Effect of Moringa oleifera-Based Coagulant and Ultrafiltration for the Wastewater Treatment Collected from Final ETP

Provision of safe drinking water, devoid of aetiologies, is an all-time challenge due to the usage of unsafe chemicals in most of the water treatment processes. The main objective of the present paper is to evaluate the use of Moringa oleifera (MO) as a natural coagulant in coagulation/flocculation (C/F) followed by the ultrafiltration (UF) of Final Effluent Treatment Plant wastewater treatment which can also be employed as an alternative to the present conventional methods of treatment. Process efficiency was evaluated in terms of chemical oxygen demand (COD), biochemical oxygen demand (BOD), turbidity, total hardness, alkalinity, ammoniacal nitrogen, and zeta potential along with permeability and fouling behaviour of the membrane. A significant improvement in both the physical and chemical characteristics of the effluent quality is showing a clearer colour and a greater reduction in BOD (89.74%) and COD (63.80%) values, while pH was in the acceptable range for effluent disposal. The results indicate a lower membrane fouling rate (49%), an increase in permeate flow, and better quality of the permeate, proving that the C/F-UF treatment is an effective and efficient technique for wastewater treatment. Eventually, the treated wastewater obtained with this process generates better quality water and preserves the aquatic ecosystem.

Computational-Based Approaches for Predicting Biochemical Oxygen Demand (BOD) Removal in Adsorption Process

Predicting the adsorption performance to remove organic pollutants from wastewater is an essential environmental-related topic, requiring knowledge of various statistical tools and artificial intelligence techniques. Hence, this study is the first to develop a quadratic regression model and artificial neural network (ANN) for predicting biochemical oxygen demand (BOD) removal under different adsorption conditions. Nanozero-valent iron encapsulated into cellulose acetate (CA/nZVI) was synthesized, characterized by XRD, SEM, and EDS, and used as an efficient adsorbent for BOD reduction. Results indicated that the medium pH and adsorption time should be adjusted around 7 and 30 min, respectively, to maintain the highest BOD removal efficiency of 96.4% at initial BOD [Formula: see text] mg/L, mixing [Formula: see text] rpm, and adsorbent dosage of 3 g/L. An optimized ANN structure of 5–10–1, with the “ trainlm” back-propagation learning algorithm, achieved the highest predictive performance for BOD removal ([Formula: see text]: 0.972, Adj-[Formula: see text]: 0.971, RMSE: 1.449, and SSE: 56.680). Based on the ANN sensitivity analysis, the relative importance of the adsorption factors could be arranged as [Formula: see text]. A quadratic regression model was developed to visualize the impacts of adsorption factors on the BOD removal efficiency, optimizing pH at 7.3 and time at 46.2 min. The accuracy of the quadratic regression and ANN models in predicting BOD removal was approximately comparable. Hence, these computational-based methods could further maximize the performance of CA/nZVI material for removing BOD from wastewater under different adsorption conditions. The applicability of these modeling techniques would guide the stakeholders and industrial sector to overcome the nonlinearity and complexity issues related to the adsorption process.

Performance of Common Reed (Phragmites australis) in a Constructed Wetland for Greywater Treatment in Akure, Nigeria

Shortage of freshwater is becoming a growing problem in both dry and semi-dry regions of the world, hence the need to make use of other source of water for agricultural production. The study was conducted to examine the performance of common reed in a constructed wetland for greywater treatment in Akure, Nigeria. Raw greywater was collected from Jadesola Hostel, Federal University of Technology, Akure, and pretreated through a combination of gravel of diameters < 32 mm, 24 mm and 16 mm with fine sand of diameter 0.2 mm arranged accordingly. The filtered water was thereafter released to a plastic constructed wetland (CW) which also consisted of same combination of layers of gravel and sand with common reed planted on it for complete treatment. The raw and treated greywater were analyzed for Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Dissolved Solid (TDS), and heavy metals. It was discovered that CW planted with common reed was effective in the treatment of greywater with reduction in BOD by 91.4%, COD by 91.5% and TDS by 38.7%. CW had appreciable removal effect on heavy metals with reduction in: manganese (Mn) from 0.100 ppm to 0.012 ppm, iron (Fe) from 0.014 ppm to 0.002 ppm, lead (Pb) from 0.05 ppm to 0.001 ppm and zinc (Zn) from 0.154 ppm to 0.148 ppm. Therefore, the use of common reed in constructed wetland for greywater treatment is recommended for farmers involved in irrigation with greywater, especially during dry seasons, and most importantly under the rising global water scarcity due to climate change.

Batch Electrocoagulation Process for Removal of Chromium from Tannery Wastewater

This study was aimed to investigate the chromium removal from the tannery wastewater through electrocoagulation. The zinc and copper plates were used as electrodes for the electrocoagulation process. The effectiveness of the electrocoagulation for chromium removal efficiency was examined investigating various parameters: applied voltage, time, and current density. In batch experiment, 500 mL chromium-containing wastewater was used for electrocoagulation. Chromium content in the raw wastewater and after treatment at optimized conditions was 340.1 and 6.9 mg/L, respectively. The efficiency of chromium removal and reduction of biochemical oxygen demand (BOD) was at 98.0 and 64.6%, accordingly. Although total dissolved solids (TDS) was slightly increased. The increment of current density enhances forming zinc hydroxide which causes the damage of electrodes. Electrocoagulation is an effective technique to remove chromium from the wastewater especially from the tannery wastewater.
 Journal of Engineering Science 12(1), 2021, 29-34

Phycoremediation potential of Chlorella sp. on the polluted Thirumanimutharu river water

Rivers are the most significant natural resources that afford outstanding habitation and nourishment for numerous living organisms. Urbanization and industrialization pollute rivers rendering their water unhealthy for consumption. Hence, this work was designed to find a potential native pollutant removing algae from polluted water. The physicochemical properties of the tested river water such as Electric Conductivity (EC), turbidity, total hardness, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ca, SO2-, and NH3, NO3, NO2, PO4, Mg, F− and Cl− contents were not within the permissible limits. Lab-scale and field-based phycoremediation treatments with the indigenous native microalgal species, Chlorella sp. from the Thirumanimutharu river water sample were set up for 15 days with three different (Group I, II, and III) biomass densities (4 × 104, 8 × 104, and 12 × 104 cells mL−1). Group III of both the lab-scale and field based treatments showed the maximum reduction in the physicochemical parameters compared to the other groups. Further, the group III of the field based study showed an extensive reduction in BOD (34.51%), COD (32.53%), NO3, NO2, free NH3 (100%) and increased dissolved oxygen (DO) (88.47%) compared to the lab scale study. In addition, the trace elements were also reduced significantly. The pollutant absorbing active functional moieties (O–H, CO, and CN) found on Chlorella sp. had been confirmed by Fourier-Transform Infrared Spectroscopy (FTIR) analysis. In the Scanning Electron Microscope (SEM) study, significant morphological changes on the surface of the treated Chlorella sp. were noticed compared with the untreated Chlorella sp. biomass, which also confirmed the absorption of the pollutants during treatment.

Evaluation of the Bacillus cereus Strain 1-p Protease for the Unhairing of Goatskins during Leather Production

The unhairing stage of leather processing is associated with the production of significant amounts of solid and liquid wastes. The use of enzymes to replace the polluting sulphides currently used for unhairing is a viable alternative. Various proteases from different Bacillus cereus strains as well as many other bacterial strains have been used successfully for the unhairing of skins. However, no previous work has assessed the use of the crude alkaline protease extract from Bacillus cereus strain 1-p, a novel Bacillus cereus strain obtained from the shores of Lake Bogoria - a soda lake in Kenya – in the unhairing of goatskins. This study, therefore, evaluates the potential of the protease extract from the Bacillus cereus strain 1-p to unhair goatskins. Optimum variables for unhairing using the protease were investigated. Complete unhairing was achieved within 12 hours at 27°C and pH 12 using the crude enzyme. The period and temperature required for complete unhairing were significantly lower than that of other enzymatic unhairing techniques. Compared to the leather unhaired with sulphide, the leather unhaired with the enzyme did not only show superior organoleptic properties but also recorded comparable or superior physical properties, namely tensile strength (26.94 N/mm2), percentage elongation (76.29%), tear strength (43.59 N/mm), and distension at grain crack and burst (7.9 mm and 8.2 mm respectively). The wastewater from the enzymatic unhairing process recorded a significant reduction in biochemical oxygen demand (78%), chemical oxygen demand (83%), and the wastewater volume (50%) compared to the process that uses sulphide. It was concluded that the use of the crude protease extract from the Bacillus cereus strain 1-p in unhairing goatskins is feasible.

Efficiency of high rate treatment of low-strength municipality sewage by a pilot-scale combination system of a sedimentation tank and a down-flow hanging sponge reactor

ABSTRACT Down-flow hanging sponge (DHS) reactor that is sponge-based trickling filter was considered to be an alternative aerobic treatment system for low strength sewage treatment under tropical conditions. This study aims to determine the process performance of the DHS reactor combined with a pre-treatment sedimentation tank (SED) system installed at the municipality sewage treatment plant in Khon Kaen, Thailand over, 1,600 days. The DHS reactor was operated with three operational periods: low (0.2 kgBODm3 per day), high (0.5–1.3 kgBODm3 per day), and super rates (1.7–2.2. kgBODm3 per day). The results showed effective reductions in biochemical oxygen demand (BOD) and suspended solids by more than 74% and 78%, respectively, during the entire experimental period. Moreover, the final effluent met the Thailand discharge standard with an external short hydraulic retention time of 0.2 h. In addition, the combined system facilitates simultaneous nitrification and denitrification and effectively removed up to 43% of total nitrogen. The self-degradation of the organic compounds occurs owing to the retained sludge in the DHS reactor; this leads to undisputed clogging in sponge media. Therefore, the combined SED-DHS system could be an appropriate sewage treatment system for tropical conditions.

Investigating leachate decontamination and biomethane augmentation through Co-disposal of paper mill sludge with municipal solid waste in simulated anaerobic landfill bioreactors

The study aims to investigate the feasibility of anaerobic co-landfilling of effluent treatment plant sludge (ETPS) from paper mill and municipal solid waste (MSW) in prismoidal shaped simulated anaerobic landfill bioreactors. Both ETPS and MSW were co-disposed in 0:100 (R1), 25:75 (R2), 50:50 (R3) and 75:25 (R4) ratios. Periodic assessments of leachate characteristics and biomethane production were carried out for 300 days. ETPS co-disposal with MSW showed considerable reduction in biochemical oxygen demand of leachate (R2: 95.9%, R3: 97.5% and R4: 93.2%). Moreover, cumulative methane gas generations were 2.974, 6.085 and 4.653 times more in R2, R3 and R4 bioreactors as compared to R1. Gompertz growth model was found in well-fitting for methane generation with the observed data. Correlogram plotted among leachate parameters exhibited exclusive relationships and justified leachate trends. This simulation of co-landfilling could be baseline study for the implementation of technology at pilot scale.

Selection of Optimum Pollution Load Reduction and Water Quality Improvement Approaches Using Scenario Based Water Quality Modeling in Little Akaki River, Ethiopia

The collective impacts of rapid urbanization, poor pollution management practices and insufficient sanitation infrastructure have driven the water quality deterioration in Little Akaki River (LAR), Ethiopia. Water quality modeling using QUAL2Kw was conducted in the LAR aimed at selecting the optimal water quality improvement and pollution load reduction approaches based on the evaluation of five scenarios: modification of point sources (PS) load (S1), modification of nonpoint sources (NPS) load (S2), simultaneous modification of PS and NPS load (S3), application of local oxygenators and fish passages using cascaded rock ramps (S4), and an integrated scenario (S5). Despite the evaluation of S1 resulting in an average load reduction of Biochemical Oxygen Demand (BOD) (17.72%), PO4-P (37.47%), NO3-N (19.63%), the water quality objective (WQO) in LAR could not be attained. Similarly, though significant improvement of pollution load was found by S2 and S3 evaluation, it did not secure the permissible BOD and PO4-P pollution load in the LAR. Besides, as part of an instream measure, a scenario evaluated using the application of rock ramps (S4) resulted in significant reduction of BOD load. All the individual scenarios were not successful and hence an integration of scenarios (S5) was evaluated in LAR that gave a relatively higher pollutant load reduction rate and ultimately was found a better approach to improve pollution loads in the river. In conclusion, pollution load management and control strategy integrally incorporating the use of source-based wastewater treatment, control of diffuse pollution sources through the application of best management practices and the application of instream measures such as the use of cascaded rock ramps could be a feasible approach for better river water quality management, pollution reduction, aquatic life protection and secure sustainable development in the LAR catchment.

Evaluating the performance of horizontal sub-surface flow constructed wetlands: A case study from southern India

Constructed wetlands are a nature-based engineering solution enabling polishing of septic tank effluents at low-cost. However to date, the influence of planting on treatment efficiency remains little understood. Here we report a case study evaluating the performance of two near-identical Horizontal Sub-Surface Flow Constructed Wetlands (HSSF-CW) deployed at a school in southern India. The HSSF-CWs were of similar size and construction with the exception that one system was planted (Canna indica) whilst the other was operated without plants. Both systems were operated at similar hydraulic loading rate (HLR) and hydraulic retention time (HRT) of 84 mm day−1 and 3.7 days, respectively to treat the effluent from septic tanks. The systems were monitored fortnightly for one year and the performance kinetics, nutrient and organics removal efficiencies were evaluated. Significant reduction in biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) (p < 0.05) were observed in both systems with BOD5 removal efficiency of 67% and 61% in the planted and unplanted systems, respectively. Whilst the effluent from both systems met the environmental discharge standards set by Central Pollution Control Board (CPCB), India, the total phosphorus (TP) and total suspended solids (TSS) removal in the unplanted system were significantly greater than in the planted system. The first-order decay rate constants (K) obtained for TN (KTN) and BOD5 (KBOD5) in the planted system (0.16 day−1 and 0.30 day−1) were higher than in the unplanted system (0.09 day−1 and 0.27 day−1). Greater R2 values obtained for the planted system (~ 0.90) suggests applicability of a first-order decay model to assess contaminant degradation. Plants contributed to 7% (0.3 g/m2/day) BOD5, 18% (1.9 g/m2/day) COD and 5% (0.09 g/m2/day) TN load removal. Our data demonstrates that planting is effective in improving treatment efficiency in constructed wetlands, and whilst the improvement is marginal here, it is noted that a rust infection could have limited effectiveness of the plants in this case.

Optimisation of an original CO2-Enhanced natural treatment system for reclaiming and reusing anaerobically digested strong wastewater from animal breeding industry

Strong wastewater from the animal breeding industry threatens the environmental and human health, while the widely used anaerobic digestion treatment is insufficient. To achieve the reclamation and reuse of the effluent containing an excessively high amount of nutrients (N, P and K) and a certain extent of biochemical oxygen demand (BOD), an original CO 2 -enhanced natural treatment system was put forward, which was composed of trickling filter and soil-plant units installed inside an elaborate greenhouse with an elevated CO 2 concentration. On the basis of previous feasibility studies , an investigation on the system’s limitations and potential were carried out for further optimisation , in which red ball earth-Kentucky bluegrass column tests were conducted at the recommended CO 2 concentration of 1,400 ppm for two specific scenarios, i.e. high BOD concentration and increasing hydraulic and nutrient loading rates. N is the most critical factor determining the effect and efficiency of the system, and results confirmed that, to establish a satisfactory nitrification function in the soil for N removal, adequate BOD reduction prior to land application was indispensable. Optimal operational strategies and parameters, as well as design information for scale-up, are also discussed. By means of nutrient balance approximation, the system’s significant capabilities of removing and recovering waterborne nutrients are further presented, specifically complete removal of both N and P, and 8%, 18% and 18% recovery rates for N, P and K, respectively. Meanwhile, carbon balance analysis reveals its potential for substantially reducing greenhouse gas emission , as 9% of the input waterborne C is sequestrated for establishing plant biomass and maintaining greenhouse CO 2 concentration at the designated level. More importantly, the above are realised in a highly profitable manner, as the value of the high-quality turf product can be an order of magnitude higher than the cost for system operation and maintenance. This original system provides an innovative way for rural communities worldwide to achieve sustainable development via wastewater reclamation and reuse. • An innovative CO 2 -enhanced natural treatment system was proposed and developed. • Ensuring sound nitrification in the soil for N removal was the most critical issue. • Significant nutrient removal and recovery and CO 2 emission reduction were achieved. • Optimal operating conditions and design information for scale-up are discussed. • The profitable system is applicable to reclamation and reuse of strong wastewater.

Vertical phytoremediation of wastewater using Vetiveria zizanioides L.

In many areas, wastewater feeds water bodies, which leads to it being non-usable for agricultural and other uses. Phytoremediation is a scientific approach which cleans contaminated waters, demanding large areas for application. Vertical agriculture is a new method to compact plant cultures. This study investigates vertical wastewater phytoremediation (VWP). Twenty vetiver grasses were planted in a hydroponic vertical agriculture system. Wastewater flowed into the system in four different flow rates, 60, 80, 100, and 160 l day-1 and water purity was assessed in order to measure the remediation ability of the VWP. Results showed a reduction in biochemical oxygen demand (BOD5 and NO3- concentrations and an increase of electrical conductivity (EC) and dissolved oxygen (DO) in the outlet. Maximum and minimum (BOD5) reduction percentage (78.47% and 67.36%) and NO3- removal percentage (90.53% and 36.41%) occurred in flow rates 60 and 160 l day-1, respectively. With the increase of wastewater flow rate, phytoremediation performance decreased, but the performance of VWP with vetiver grass was efficient enough to enable wastewater remediation. Scaling up VWP with Vetiver and related competitive plant species holds promise for wastewater remediation for both human and ecosystem services.

Performance Efficiency of Common Reed, Sand and Gravel for Greywater Treatment in a Constructed Wetland in Akure, Nigeria

The release of greywater lacking any treatments into drainage channels, land surfaces and normal water bodies will lead to environmental deprivation and health risks. In this study, common reed combined with natural materials of sand and gravel was used in a system of constructed wetland for the treatment of greywater in Akure, Nigeria. Raw greywater (RGW) was collected from Jadesola Hostel, Federal University of Technology, Akure, and pretreated using a combination of gravel with fine sand, arranged accordingly. The filtered water was subsequently released to a plastic constructed wetland (CW) consisting of similar combination of layers of gravel and sand with common reed planted on it to achieve complete treatment. The RGW, filtered greywater (FGW) and treated greywater (TGW) were analyzed for biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), total nitrogen (TN) and fecal coliforms (FC). Results showed reductions in BOD, COD, TSS, TN and FC by 80.20%, 78.35%, 56.07%, 45.93% and 74.71%, respectively, for FGW and by 90.92%, 91.46%, 93.46%, 53.66% and 82.10%, respectively, for TGW. Therefore, it was concluded that the combination of common reed, sand and gravels in constructed wetland offers an effective means of accomplishing physical and biological treatment of greywater, especially for reuse in irrigation. Hence, it was recommended that acceptance of the combined system will help farmers in ensuring sufficient treatment of greywater and satisfies the standard requirements for wastewater reuse and application in both field crop irrigation and other outdoor needs.

Seasonal Variability and Wastewater Treatment Efficiency in Federal Capital Territory, Abuja

The study examined efficiency and seasonal variations in municipal wastewater treatment in Federal Capital Territory, Abuja. Wastewater treatment data from year 2015 to 2018 were analysed and compared with National Environmental Standard and Regulations Enforcement Agency permissible limit. The data were analysed to determine if seasonal variations exist in the performance of the wastewater treatment plant. The study was undertaken in the wastewater treatment plant located at Wupa, Abuja. The result obtained show that in 2015 a high reduction in biochemical oxygen demand (BOD) (84.6%) and chemical oxygen demand (COD) (85.4%) with excellent pH value (7.3pH, 90.8%) was achieved. In 2016, there was a significantly high level of treatment in Faecal Coliform (99.1%), BOD (93.4%), total suspended solids (TSS) (91.7%), COD (87.6%), and Ammonia (71.5%). In 2017, the level of treatment for BOD, COD and TSS were 97.2%, 95.7% and 95.4% respectively. While in 2018, removal efficiency of BOD was 95.2%, COD 91.6% and TSS 90.6%. The result also revealed that the observed values of the biochemical parameters are considerably lower when compared with the National Environmental Standards, Regulations and Enforcement Agency (NESREA) standards (i.e., p<0.05). The seasonal comparative result shows that the BOD total in dry season is significantly higher compared to the rainy season (t*=-3.553, p=0.001<0.05). The average COD in rainy season is slightly lower compared to that in dry season, and however, statistically insignificant (t*=-1.690, p=0.098). The TSS and pH values in rainy season are slightly and insignificantly lower compared with the values in the dry season. Continuous monitoring is recommended.

Reduction of organic and biological pollutants from affluents of the Ancón wastewater treatment plant using microanobubbles of air and graphene [Reducción de contaminantes orgánicos y biológicos de afluentes de la planta de tratamiento de aguas residuales de Ancón utilizando micronanoburbujas de aire y grafeno

The objective of this research was to reduce the organic and biological load of tributaries of the Ancón Wastewater Treatment Plant using microanobubbles of air and graphene. A preliminary sample of the affluent (3L) was taken, which had an initial concentration of Biochemical Oxygen Demand (BOD5) of 410 mg/L, Chemical Oxygen Demand (COD) of 483 mg/L, Thermotolerant Coliforms of 44,000 NMP/100mL and turbidity of 63.33 NTU. The experimental part was carried out with 03 samples of 20 liters with 03 repetitions with a treatment time of 20, 40 and 60 minutes applying air nanobubbles and 6, 12 and 18 grams of graphene respectively. The results of the treated samples were: 87 mg/L representing 78.8% reduction in Biochemical Oxygen Demand (BOD5), 114 mg/L representing 76.4% reduction in Chemical Oxygen Demand (COD), 2,900 NMP/100mL that represents 93.41% reduction of Thermotolerant Coliforms and 12.4 NTU that represents 80.11% reduction of turbidity.

A brief review on biochemical oxygen demand (BOD) treatment methods for palm oil mill effluents (POME)

Numerous issues pertaining to palm oil mill effluents (POME), such as the release of high level of biochemical oxygen demand (BOD) and other pollutants into the environment, have brought major public concern. Hence, Department of Environment (DOE) has implemented stricter laws on the final discharge of POME, whereby BOD must be less than 20 mg L −1 . Addressing that, the recent types of treatment methods to reduce BOD were briefly reviewed in this article. A lower value of BOD can be achieved by improving both biological and physiochemical treatment methods for POME. The palm oil industry has also recently combined the existing treatment and biogas capture technology to create an integrated system to reduce BOD effectively, and at the same time, make full use of the valuable by-products, such as methane gas, as part of the effort to realise the idea of zero discharge waste. In conclusion, based on the previous studies, of whether in small or large scale, it is recommended to include information of BOD reduction for future research guidelines, which can be used to address related palm oil waste discharge issues for better environmental quality. • Various BOD treatment methods for POME has been reviewed. • The research gap due to the new 20 mg/L BOD discharge limit is mentioned. • Sonochemical oxidation with activated carbon adsorbent removed 100% of BOD. • Integrated system technology is found to be the best solution for BOD treatment.

Chromium Adsorption on Banana Rachis Adsorbent from Tannery Wastewater

This study investigates the banana rachis adsorbent for adsorption characterization, removal, and recovery of the chromium ion from the chrome tanning wastewater. The batch analysis was conducted to find out an adsorbent dose, contact time, relative pH of the aqueous solution, and initial and final chromium value in the filtrate. The equipped adsorbent was studied by the Fourier transform infrared spectroscopy (FT-IR) analysis to reveal the associated functional groups during adsorption. Batch adsorption examination reveals the optimum conditions of 3 g adsorbent input for 75 mL wastewater at 15 min contact time. The adsorption mechanism showed chromium removal 99.64% with the obtained reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and chloride (Cl-) 96.65%, 93.18%, and 59.62%, respectively. The adopted method followed the pseudo-second-order kinetics and Freundlich isotherm for physical adsorption. Primary desorption studies exhibit a scope for the reuse of chromium from the adsorbed adsorbent. Moreover, in comparison with other studies, the study discloses that banana rachis might be utilized as a feasible adsorbent to be adopted in industrial wastewater treatment, especially chrome tanning wastewater in the tannery.

Aquatic plants as phytoremediator for common carp fish (Cyprinus carpio) culture

This research was conducted to optimize the performance of aquatic plants in maintaining water quality in common carp breeding. This study consisted of three treatments, namely: A. Lemna minor, B. Azolla pinnata, and C. Control (without plant) with three replications. The size of common carp juvenile used was ± 3 cm with a density of 150 individuals/m2. Feed was given ad satiation. The parameters observed were survival rate, weight, daily growth rate, water quality such as Biochemical Oxygen Demand (BOD), nitrogen and phosphate reduction. The research design used was Completely Randomized Design (CRD) with Analysis of Variance (ANOVA). Whereas the effectiveness of aquatic plants and water quality analyzed descriptively. The results showed that the highest survival rate and productivity of common carp breeding ponds were in treatment B, namely 86% and 463.80g. The growth rates between the three treatments were not significantly different (p> 0.05), each of which was 0.08; 0.08 and 0.09 g day−1. The BOD reduction results in treatments A, B, and C, respectively 54.65, 54.65 and 52.33%. Nitrogen reduction in each treatment was (A) 67.54%; (B) 87.37%: (C) 25.27%. Furthermore, treatment A and B did not differ in the reduction of elemental P, respectively 52.68 and 55.20%, but in C the reduction was still low at 36.75%. Optimum water quality for dissolved oxygen in treatment A, B, and C respectively 7.24; 7.57 and 3.14 mg L−1. The temperature range between treatments was 24.5 - 27.2 with a pH value of 6.00 - 6.87.