Biochemical Oxygen Demand Test Research Articles

One- and two-step synthesis of paramylon mixed ester derivatives and the substitution effect on mechanical properties and seawater biodegradability

Paramylon acetate hexanoate (PaAcHex) with total DS=1.7 was prepared by one- and two-step methods with acetylation and hexanoylation in different order (denoted as AcHex and HexAc) in homogeneous DMAc/LiCl. The distribution of substitution at various ring carbon atoms (C2, C4, and C6) of PaAcHex synthesized by different methods was determined by 1H NMR spectroscopic analysis. The AcHex mixed esters showed a higher DS of long-chain Hex on C2 and C4 than the other samples. All mixed esters were amorphous and their glass transition temperatures (Tg) were obtained from DMA measurements. PaAcHex with higher DS of hexanoate groups had lower Tg and their melt films showed higher flexibility at the same total DS for all three series of samples. PaAcHex films produced by the two-step (AcHex) method exhibited high toughness even with a low DS of hexanoate groups, whereas those synthesized by the one-step and two-step (HexAc) methods were weak and brittle. Biochemical oxygen demand tests indicated that the mixed esters prepared by the two-step (AcHex) method underwent a two-step degradation process, which may be related to the hexanoate groups on C2 and C4. Short–long chain acylation by the two-step (AcHex) method was found to be the optimal synthesis technique for polysaccharide esters that displayed favorable thermoplasticity and controllable seawater biodegradation behavior. These polysaccharide esters show promise as bioplastic materials.

Biodegradability of oxidized films of polyhydroxyalkanoate copolymers containing 2-hydroxy-4-methylthiobutyrate unit in seawater

Polyhydroxyalkanoate (PHA) copolymers consisting of 3-hydroxybutyrate, 2-hydroxy-4-methylthiobutyrate (2H4MTB), and 2-hydroxy-4-methylvalerate were biosynthesized by recombinant Escherichia coli using L-methionine as the 2H4MTB precursor. The 2H4MTB unit contains a sulfide group in its side chain that can be oxidized to sulfoxide and sulfone groups by oxidants, thereby increasing the hydrophilicity of the polymer. The PHAs were biosynthesized at 3.9, 9.2, and 13.9 mol% 2H4MTB, and their polymer films were oxidized with hydrogen peroxide. The surface of the oxidized film was characterized using Fourier-transform infrared spectroscopy, Raman spectroscopy, and contact angle analysis. The oxidized films with 13.9 mol% 2H4MTB showed a 30° lower water contact angle than the non-oxidized films. To assess their marine biodegradability, the PHA films were immersed for 114 days in seawater continuously pumped from two depths (24 and 397 m) in Suruga Bay, Shizuoka, Japan. The weight loss of the films immersed in deep seawater was higher than that of those immersed in surface seawater. Additionally, there was a tendency for higher degradation of the oxidized films than that of the non-oxidized films, which was also confirmed by the biochemical oxygen demand test. In the surface morphology analysis by scanning electron microscopy, irregularities were observed in the degraded films, but their morphologies differed between the oxidized and non-oxidized films. Based on these observations, the biodegradation of the PHA films in seawater is discussed.

Resilience of anodic biofilm in microbial fuel cell biosensor for BOD monitoring of urban wastewater

Efficient wastewater treatment monitoring is vital for addressing water scarcity. Microbial fuel cells (MFCs) have emerged as real-time biosensors for biochemical oxygen demand (BOD) in urban wastewater. Discrepancies in signal generation may arise due to changes in the composition and metabolism of mixed-culture electroactive biofilms stemming from different wastewater compositions. In this study, 3D-printed MFC-based biosensors were employed to assess the BOD of sterile complex artificial wastewater and untreated urban wastewater. Alterations in the microbial composition of the anode were evaluated using 16S rRNA sequencing and metagenomics analysis. Results show that MFC-based biosensors can be effectively recalibrated for diverse types of wastewater, maintaining consistent sensitivity (0.64 ± 0.10 mA L mg−1 m−2 with synthetic wastewater and 0.78 ± 0.13 mA L mg−1 m−2 with urban wastewater) and limit of detection (49 ± 8 mg L−1 for synthetic wastewater and 44 ± 7 mg L−1 for urban wastewater). Crucially, pre-sterilization, conductivity adjustments, and nitrogen purging of wastewater are not required before its introduction into the biosensor. However, the presence of native aerobic microorganisms in the wastewater might affect the current output. Metagenomics and taxonomic analyses revealed that the alterations in biofilm composition are predominantly in response to the varied chemical and microbiological compositions of different substrates. Despite variations in anodic biofilm composition, the MFC-based biosensor maintains a relative error comparable to the standard BOD test. This highlights the resilience and flexibility of the biosensor when directly used with a variety of wastewater types before full biofilm adjustment.

Enhanced Marine Biodegradation of Polycaprolactone through Incorporation of Mucus Bubble Powder from Violet Sea Snail as Protein Fillers.

Microplastics' spreading in the ocean is currently causing significant damage to organisms and ecosystems around the world. To address this oceanic issue, there is a current focus on marine degradable plastics. Polycaprolactone (PCL) is a marine degradable plastic that is attracting attention. To further improve the biodegradability of PCL, we selected a completely new protein that has not been used before as a functional filler to incorporate it into PCL, aiming to develop an environmentally friendly biocomposite material. This novel protein is derived from the mucus bubbles of the violet sea snail (VSS, Janthina globosa), which is a strong bio-derived material that is 100% degradable in the sea environment by microorganisms. Two types of PCL/bubble composites, PCL/b1 and PCL/b5, were prepared with mass ratios of PCL to bubble powder of 99:1 and 95:5, respectively. We investigated the thermal properties, mechanical properties, biodegradability, surface structure, and crystal structure of the developed PCL/bubble composites. The maximum biochemical oxygen demand (BOD) degradation for PCL/b5 reached 96%, 1.74 times that of pure PCL (≈55%), clearly indicating that the addition of protein fillers significantly enhanced the biodegradability of PCL. The surface morphology observation results through scanning electron microscopy (SEM) definitely confirmed the occurrence of degradation, and it was found that PCL/b5 underwent more significant degradation compared to pure PCL. The water contact angle measurement results exhibited that all sheets were hydrophobic (water contact angle > 90°) before the BOD test and showed the changes in surface structure after the BOD test due to the newly generated indentations on the surface, which led to an increase in surface toughness and, consequently, an increase in surface hydrophobility. A crystal structure analysis by wide-angle X-ray scattering (WAXS) discovered that the amorphous regions were decomposed first during the BOD test, and more amorphous regions were decomposed in PCL/b5 than in PCL, owing to the addition of the bubble protein fillers from the VSS. The differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA) results suggested that the addition of mucus bubble protein fillers had only a slight impact on the thermal properties of PCL. In terms of mechanical properties, compared to pure PCL, the mucus-bubble-filler-added composites PCL/b1 and PCL/b5 exhibited slightly decreased values. Although the biodegradability of PCL was significantly improved by adding the protein fillers from mucus bubbles of the VSS, enhancing the mechanical properties at the same time poses the next challenging issue.

Effects of Molecular Weight on the Marine Biodegradability of Poly(l-lactic acid).

Poly(l-lactic acid) (PLA) is a biodegradable bioplastic with limited marine degradation. This study examines the impact of molecular weight on PLA's marine biodegradability. We synthesized PLA with terminal hydroxyl groups (PLA-OH) with degrees of polymerization (DP) between 14 and 642 and conducted biochemical oxygen demand (BOD) tests. Samples with a DP of 422 or 642 did not degrade, like commercial PLA. However, PLA-OH with a DP below 314 showed biodegradability, with DP 14 exhibiting a higher degradability than cellulose. Size exclusion chromatography (SEC) confirmed a decrease in molecular weight for samples with DPs below 314, indicating extracellular microbial activity. These findings suggest that PLA-OH with a DP under 314 can be degraded in marine conditions, unlike high-molecular-weight PLA. If the DP of high-molecular-weight PLA can be reduced to 314 by some specific method, then it is expected that PLA can be used to create marine biodegradable materials.

Improving the marine biodegradability of poly(alkylene succinate)-based copolymers

AbstractWe report the syntheses of novel marine biodegradable poly(ethylene succinate) (PES)- and poly(butylene succinate) (PBS)-based copolymers containing different dicarboxylic acid (DCA) units with various carbon numbers and different feed ratios. Biochemical oxygen demand tests demonstrated that some of the obtained PES- and PBS-based copolymers were biodegradable in seawater. Specifically, polymers with longer-chain DCA units, even at low contents, exhibited marine biodegradability. The thermomechanical properties of the copolymers, such as their thermal stabilities, melting points, glass transition temperatures, tensile moduli, strains at break, and stresses at break, also varied with the DCA contents. These results indicated that the thermomechanical properties and the marine biodegradabilities of the PES- and PBS-based copolymers were regulated by controlling their structures and DCA contents. The polymers obtained in this study may replace general-purpose polymers. Our approach may also be applicable to other polymeric materials. Furthermore, our findings pave the way for the rational design and preparation of polymeric materials that are biodegradable in environments other than oceans and have good thermomechanical properties.

Marine biodegradation of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] elastic fibers in seawater: dependence of decomposition rate on highly ordered structure.

Here, we report the marine degradability of polymers with highly ordered structures in natural environmental water using microbial degradation and biochemical oxygen demand (BOD) tests. Three types of elastic fibers (non-porous as-spun, non-porous drawn, and porous drawn) with different highly ordered structures were prepared using poly[(R)-3-hydroxybutyrate-co-16mol%-4-hydroxybutyrate] [P(3HB-co-16mol%-4HB)], a well-known polyhydroxyalkanoate. Scanning electron microscopy (SEM) images indicated that microorganisms attached to the fiber surface within several days of testing and degraded the fiber without causing physical disintegration. The results of BOD tests revealed that more than 80% of P(3HB-co-16mol%-4HB) was degraded by microorganisms in the ocean. The plastisphere was composed of a wide variety of microorganisms, and the microorganisms accumulated on the fiber surfaces differed from those in the biofilms. The microbial degradation rate increased as the degree of molecular orientation and porosity of the fiber increased: as-spun fiber < non-porous drawn fiber < porous drawn fiber. The drawing process induced significant changes in the highly ordered structure of the fiber, such as molecular orientation and porosity, without affecting the crystallinity. The results of SEM observations and X-ray measurements indicated that drawing the fibers oriented the amorphous chains, which promoted enzymatic degradation by microorganisms.

Wastewater Treatment Using Fruit Peels and Rice Husks

Domestic and industrial activities produce wastewater that contain dangerous pollutants that might be harmful to society, public authorities and industry. As the world’s population grows and natural habitats deteriorate, securing clean water sources for everyone became more difficult. Remediation of wastewater using activated carbon from bio materials which is fruit peels and rice husks is gaining attention among research, as it reduces the cost of activated carbon production. Hence, activated carbon from rice husks and fruit peels were proposed to be used for wastewater treatment in this study. The activated carbon from fruit peels and rice husks are used to remediate wastewater using absorption method that are a low-cost and environmentally friendly alternative in treating wastewater. Carbonization process is the main approach to produce an activated charcoal, followed by chemical activation and adsorption process. The treated wastewater then undergoes several tests to evaluate the quality of wastewater after absorption treatment such as Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), pH test, colour test and heavy metal removal test. As a result, for COD test, the value of untreated and treated wastewater is 1.24 mg/L and 0.53 mg/L. For BOD test for treated and untreated wastewater is 4.98 mg/L and 3.90 mg/L. It also changed the pH value from 8.21 to 7.98 after the treatment process. For colour test, it also decreased for before and after treatment which is 91 %. For heavy metal removal, which is Zinc metal, the value also decreased from 0.0097 mg/L to 0.0052 mg/L. It is proven that fruit peels and rice husks to be effective to treat the textile wastewater while still being low cost-effective for its production.

Thermal Embedding of Humicola insolens Cutinase: A Strategy for Improving Polyester Biodegradation in Seawater.

By thermal embedding of the commercially available enzyme Humicola insolens cutinase (HiC), this study successfully enhanced the biodegradability of various polyesters (PBS, PBSA, PCL, PBAT) in seawater, which otherwise show limited environmental degradability. Melt extrusion above the melting temperature was used for embedding HiC in the polyesters. The overall physical properties of the HiC-embedded films remained almost unchanged compared to those of the neat films. In the buffer, embedding HiC allowed rapid polymer degradation into water-soluble hydrolysis products. Biochemical oxygen demand tests showed that the HiC-embedded polyester films exhibited similar or much higher biodegradability than the biodegradable cellulose standard in natural seawater. Thermal embedding of HiC aims to accelerate the biodegradation of plastics that are already biodegradable but have limited environmental biodegradability, potentially reducing their contribution to environmental problems such as marine microplastics.

Isolation and characterization of polyhydroxyalkanoate-degrading bacteria in seawater at two different depths from Suruga Bay.

Polyhydroxyalkanoate (PHA) is a highly biodegradable microbial polyester, even in marine environments. In this study, we incorporated an enrichment culture-like approach in the process of isolating marine PHA-degrading bacteria. The resulting 91 isolates were suggested to fall into five genera (Alloalcanivorax, Alteromonas, Arenicella, Microbacterium, and Pseudoalteromonas) based on 16S rRNA analysis, including two novel genera (Arenicella and Microbacterium) as marine PHA-degrading bacteria. Microbacterium schleiferi (DSM 20489) and Alteromonas macleodii (NBRC 102226), the type strains closest to the several isolates, have an extracellular poly(3-hydroxybutyrate) [P(3HB)] depolymerase homolog that does not fit a marine-type domain composition. However, A. macleodii exhibited no PHA degradation ability, unlike M. schleiferi. This result demonstrates that the isolated Alteromonas spp. are different species from A. macleodii. P(3HB) depolymerase homologs in the genus Alteromonas should be scrutinized in the future, particularly about which ones work as the depolymerase.

Hydrochemical Characteristics and Self-Purification Potential of Iyiechu Stream in Okigwe Area, Southeastern Nigeria

Iyiechu stream is a small tropical urban stream that receives both domestic and industrial wastes. The self-purification potential of the stream was determined by evaluating its deoxygenation and reaeration rate coefficients. The methods of study used include dissolved oxygen (DO) measurements, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) tests as well as measurements of hydrological parameters. Deoxygenation rate of 0.20 to 0.42/day were obtained indicating very swift depletion of oxygen in the stream probably as a result of domestic sewage input. The reaeration rate coefficients ranged from 0.01 to 0.84 day and these values suggest deep and slow moving streams. The measured DO values are quite low, indicating high deoxygenation reaction in the stream and minimal dissolved oxygen contribution from other sources such as algal photosynthesis. Spatially, about 66.66% of the stream is dominated by deoxygenation reaction. The chemical oxygen demand ranged from 20 to 40 mg/l. These values are relatively high and show that the process may be partly responsible for the low dissolved oxygen levels in the stream. However, the stream is capable of re-attaining its optimum dissolved oxygen level within a flow time of 0.84 day (20hrs 16minutes) in the rainy season. Thus, a flow time much greater than 0.84 day (20hrs 16minutes) would be required during the dry season. These flow times suggest that the stream has poor self-purification potential.

Impact of Artisanal Crude Oil Refining Effluents on Interstitial Water at a Mangrove Wetland, Asari-Toru Axis of Sombreiro River, Rivers State.

A comparative study on the water quality of the interstitial water of two creeks in Rivers State was conducted. Temperature, pH, Conductivity, Dissolved oxygen, biochemical oxygen demand, Salinity, and Total dissolved solid were checked with an in-situ hand-held multi-meter (The EZODO Multi-meter). Dissolved oxygen (DO) was measured with a Milwaukee Dissolved oxygen meter while Biochemical Oxygen Demand (BOD) was determined by the 5-day BOD test (APHA, 2005). The temperature ranged between 28.3 to 29.3℃ in the Opro-ama creek and 26.0 -26.8℃ in Buguma creek. The pH value ranged from 6.2 to 6.8 in Opro-ama creek while that of Sa-ama creek was between 6.8 and 6.99. Salinity ranges from 9.1 to 9.5 (ppt) in the Opro-ama creek while Sa-ama creek recorded a range between 11.2 to 12.0 (ppt). The dissolved oxygen was between 1.5 and 2.3 (µS/cm) in Okpoka creek meanwhile Sa-ama creek varied between 4.6 and 4.10 (µS/cm). The biochemical oxygen demand values were between 1.4 to 2.3 (µS/cm) in Opro-ama creek while that of Sa-ama was between 1.9 to 2.4 (µS/cm). The conductivity values for the Opro-ama creek were between 10.3 and 10.6 while Sa-ama creek recorded a value of 12.5 to12.6 (µS/cm). there were significant variations (P

Synthesis and Biodegradability of Tartaric Acid-Based Poly(ester-thioether)s via Thiol-Ene Click Polymerization.

Using scandium triflate [Sc(OTf)3] as a catalyst, chemoselective esterification of tartaric acids by 3-butene-1-ol was performed, and we produced three dialkene monomers: l-di(3-butenyl) tartrate (BTA), d-BTA, and meso-BTA. Thiol-ene polyaddition of these dialkenyl tartrates and dithiols including 1,2-ethanedithiol (ED), ethylene bis(thioglycolate) (EBTG), and d,l-dithiothreitol (DTT) proceeded in toluene at 70 °C under nitrogen to give tartrate-containing poly(ester-thioether)s (Mn, (4.2-9.0) × 103; molecular weight distribution (Mw/Mn), 1.6-2.5). In differential scanning calorimetry, the poly(ester-thioether)s showed single Tgs between -25 and -8 °C. In biochemical oxygen demand (BOD) tests using activated sludge, poly(l-BTA-alt-EBTG) and poly(l-BTA-alt-ED) showed 32 and 8% biodegradability, which is comparable to that of similar l-malate-containing poly(ester-thioether)s (23 and 13% biodegradation, respectively). Notably, we observed enantio and diastereo effects on biodegradation because poly(l-BTA-alt-EBTG), poly(d-BTA-alt-EBTG), and poly(meso-BTA-alt- EBTG) showed different degradation behaviors during the biodegradation test (BOD/theoretical oxygen demand (TOD) values after 28 days, 32, 70, and 43%, respectively). Our findings provide insights into the design of biomass-based biodegradable polymers containing chiral centers.

Quality Control Assessment in the River of Kajang, Selangor, Malaysia

This paper investigates the biochemical oxygen demand (BOD) and the pH level along Jelok River, Kajang, Selangor, Malaysia. The BOD and pH level are of major interest as microbial activity. Five water sampling locations along the river have been selected. To test the pH level of each water sample, a pH meter was used. To test the BOD of each water sample, the 5-days BOD test was conducted. Using the collected data, the Pearson’s correlation coefficient between the pH and BOD was calculated. The computed Pearson correlation coefficient is -0.67988, indicating that pH does affect BOD of the water, specifically for this river. In addition, it demonstrates that when pH value increases, BOD of the water will decrease. The results show that water pH was quite stable, range between 7.05 to 7.65, while BOD fluctuates wildly, range between 1.4 to 4.3 mg/L. According to the BOD value, the high BOD value was found along the bridge at Changkat Road with 4.3 mg/L, and the lowest was found to be the one at Shell Petrol Station along Semenyih Road with BOD value of 1.4 mg/L. From the findings, public and authority shall be alert of the water performance and actions are necessary to preserve the water quality along this river. In addition, it is recommended to compare the water quality parameters among few rivers in future studies.

Assessment of statistical methods for converting biochemical oxygen demand and carbonaceous biochemical oxygen demand to total organic carbon in wastewater

AbstractThe 5‐day biochemical oxygen demand (BOD5) and carbonaceous BOD5 (CBOD5) tests are widely used parameters for monitoring wastewater. Total organic carbon (TOC) has many advantages over these tests. Wastewater utilities have conducted studies to modify National Pollutant Discharge Elimination System (NPDES) permits to allow TOC analysis; however, statistical methods vary across studies. This study examined parametric and nonparametric correlation and parametric, nonparametric, and nonlinear regression methods for analysing BOD5, CBOD5, and TOC concentrations collected for 1 year from seven wastewater treatment plants from the Metropolitan Water Reclamation District of Greater Chicago. Spearman ρ correlation and Theil–Sen regression on log‐transformed concentrations were the most appropriate methods. Correlation coefficients were 0.83 or greater and regression residuals were as small as or smaller than the other two methods. This study demonstrated that nonparametric methods performed best for analysing non‐normal data in seeking to incorporate TOC analysis into NPDES reporting.

Predictive Sensor for Biological Oxygen Demand in water using Active Learning based Random Forest Algorithm

The environmental pollution caused by human beings, and industries is interfering with water sources thatbound the living zones in marine environments. Greywater reuse after treatment can be carried out for non-consumable water use and hence Biochemical oxygen demand (BOD) is a vital parameter in deciding the nature of waste water created. The measurement of BOD involves difficulties and performing the BOD test takes too long and the result does not remain relevant for the current wastewater. This work proposes an ensemble learning-based random forest model with active learning to iteratively select samples with large ambiguity for reducing errors in predicting BOD. The model uses minimal basic physical &amp; chemical parameters of water and hence does not require specialized ion-selective and costly sensors for measurement. Feature importance is exploited to enhance the efficiency of the machine learning model leading to a prediction accuracy of 81.21%. The developed model could be used as a predictive sensor at the edge of the water quality monitoring system

Synthesis and characterization of novel potentially biodegradable aromatic polyesters consisting of divanillic acids with free phenolic hydroxyl groups

Potentially biodegradable bio-based polyesters (P6DVAs) were synthesized from 1,6-hexanediol and divanillic acid (DVA) with free hydroxyl groups. Four DVA-based monomers with different silyl protecting groups were synthesized. Each silyl protected monomer was polymerized with 1,6-hexanediol by bulk transesterification using tetraisopropyl orthotitanate as a catalyst at 140–180 °C (first step), and 200–220 °C under vacuum (second step). Triisopropylsilyl (TIPS) -protected DVA polymerization proceeded without the elimination of TIPS groups, and a TIPS-protected DVA polyester was obtained. After deprotection of the TIPS groups, a P6DVA (weight-average molecular weight; Mw = 3.9 × 104, polydispersity; 1.4) was obtained. The P6DVA was an amorphous polymer with a glass transition point of 108 °C. Environmental degradability was assessed by a biochemical oxygen demand (BOD) test using a mixture of fresh water and soil collected from a pond. The BOD degradability of the P6DVA was 8% over 40 days, indicating its potential as a degradable polymer.

Didecyldimethylammonium Chloride- and Polyhexamethylene Guanidine-Resistant Bacteria Isolated from Fecal Sludge and Their Potential Use in Biological Products for the Detoxification of Biocide-Contaminated Wastewater Prior to Conventional Biological Treatment.

Simple SummaryEvery year, more than a million tons of fecal sludge (FS) containing biocides based on quaternary ammonium compounds and guanidine derivatives, which are widely used for FS deodorization and control of microbial activity, are generated in the environmentally safe toilet complexes of Russian Railways trains. Higher disposal costs for such biocide-contaminated FS due to activated sludge toxicity increases pressure on sanitary equipment servicing companies («Ecotol Service» LLC) to more efficiently discharge FS to wastewater treatment plants. In this work, we have developed a new environmentally friendly approach to reducing the toxicity of FS, based on the use of biological products from biocide-resistant bacterial strains isolated from FS. Our approach has proven to be effective in a series of FS biodegradation experiments, biological oxygen demand tests, and a newly developed disk-diffusion bioassay.Toxic shock caused by the discharge of biocide-contaminated fecal sludge (FS) from chemical toilets to conventional wastewater treatment plants (WWTP) can be a major problem in activated sludge operation. It is necessary to develop new environmental approaches to mitigate the toxicity of biocides in order to avoid degrading the performance of WWTP. “Latrina”, a chemical toilet additive containing didecyldimethylammonium chloride and polyhexamethylene guanidine, is widely used in environmentally safe toilet complexes (ESTC) on Russian railway trains to deodorize FS and control microbial activity. In this work, seven biocide-resistant bacterial strains were isolated and identified from the FS of ESTC. The values of the minimum inhibitory and bactericidal concentrations of biocides for the isolated strains were 4.5–10 times higher than for the collection microorganisms. The bacterium Alcaligenes faecalis DOS7 was found to be particularly resistant to “Latrina”, the minimum inhibitory concentration of which was almost 30 times higher than recommended for ESTC. Biological products based on isolated bacterial strains proved to be effective for FS biodegradation under both aerobic and anaerobic conditions. The results of the biochemical oxygen demand test and the newly developed disk-diffusion bioassay confirmed that isolated strains contribute to reducing toxicity of biocidal agents in FS. Hyper-resistance, non-pathogenicity, and potential plant growth-promoting ability make A. faecalis DOS7 promising for use in various biological products for wastewater treatment and bioremediation of soils contaminated with biocides, as well as in agriculture to increase plant productivity.

Assesment of Sawmill and other Associated Wastes on the Water Quality of Ilo-abuchi Creek, Rivers State, Niger Delta

A study was conducted on physicochemical parameters water from Ilo-abuchi, creek Niger Delta, Nigeria. The study aimed at evaluating the impact of sawmills and other associated wastes on water quality of the creek. The physicochemical parameters investigated were from February to July 2020 and the samples were analysed for pH, Temperature, Salinity, Conductivity, Total Suspended Solid (TSS), Total Dissolved Solids (TDS), and Total alkalinity using an in-situ Handheld Multimeter (Milwaukee Model pH600 and Laboratory Benchtop meter 860033-model. The Dissolved Oxygen (DO) was measured using Winkler’s method. Biochemical Oxygen Demand (BOD) was determined by the 5-day BOD test (APHA, 2005). Turbidity was measured using a 20cm diameter Secchi disc. Total alkalinity was determined by the American Society for Testing and Materials (ASTM D 1067B) Nitrate, Chloride, Phosphate, and Sulphate were determined using the method recommended by APHA 2340C (1995) standard. Water Temperature ranges between 27.7 -27.8 OC, pH 6.65 - 6.73, Conductivity 438.2 - 494.2 μS/cm, Salinity 2.8 -3.23ppt, TDS 77 – 87.27 mg/l, TSS 30.7 - 37.66 mg/l, DO 3.19 – 3.46 mg/l, BOD 2.05 - 3.38 mg/l, Turbidity 5.41- 5.98 NTU, Nitrate 8.78 - 10.02 mg/l, Hardness 31.77 - 33.98 mg/l, Chloride 23.03 -25.7 mg/l, Phosphorus 0.31 - 0.51 mg/l, Sulphate 13.27 - 16.60 mg/l. Alterations in water quality were more pronounced in the wet season (May, June, and July) compared to the dry season (February and March, and April). The nature of the effluents discharged into the creek were found to be essentially within the acceptable limits prescribed by law except for TSD and turbidity. These two parameters were slightly above the WHO standards. It is therefore recommended that environmental regulatory agencies such as NESREA and the Ministry of Environment should devise mechanisms to enforce existing environmental regulations concerning the discharge of effluents from different sources into the Ilo-abuchi Creek, which will aid in reducing the dumping of untreated wastes from the sawmills/other associated wastes and by extension conserve the aquatic life therein.

Biodegradable, Stretchable and Transparent Plastic Films from Modified Waterborne Polyurethane Dispersions.

Waterborne polyurethane dispersions can be designed to generate highly functional and environmentally friendly polymer systems. The use of water as the main dispersion medium is very advantageous for the environment and the introduction of linear and aliphatic polyols such as polyether and polyesters in the formulations can make them highly biocompatible and susceptible to biodegradation. In this study, we fabricated biodegradable, flexible and transparent plastic films by hybridizing a waterborne aliphatic polyester polyurethane (PU) suspension with polyvinylpyrrolidone (PVP) using mechanical homogenization in water. Films were cast containing different concentrations of PVP. The hybrids containing 50 wt.% PVP (PU/PVP_50/50) were hydrophobic, stretchable, highly transparent and ductile beyond 100% strain compared to highly brittle PVP. The mechanical properties of the PU/PVP_50/50 film remained stable after repeated immersion wet–dry cycles, each lasting 2 days, and the dried films recovered their mechanical properties after each cycle. Based on a 28-day biochemical oxygen demand (BOD) test, the hybrid PU/PVP_50/50 film underwent extensive biodegradation. This simple but effective process can be very suitable in producing biodegradable ductile films with very good transparency that can serve a number of applications such as agricultural mulches, food and pharmaceutical packaging and biomedical field.