Influence of Printing Technique and Printing Conditions on Prints Recycling Efficiency and Effluents Quality

The aim of this work was to determine the influence of the conventional offset printing technique and digital electrophotography printing with liquid toner (LEP) on some optical properties of recycled fibres. A series of LEP prints was made with the variation of the negative voltage of the developing drum (−200 V, −280 V, −350 V, and −430 V) after calibration of the machine and achieving standard densitometry values. Besides deinkability aspects, the quality of wastewater effluents after process of prints recycling was observed in order to make a conclusion regarding how different printing techniques, conditions in printing process, and different types of inks can affect the wastewater effluents. Results of image analysis showed that by increasing the negative voltage of developing drum in LEP printing technique, the formation of large ink particles on handsheet from recycled pulp increases. Depending on the size of the negative voltage of the developing drum, under the same experimental conditions, handsheets made from LEP recycled fibres have lower whiteness gain, brightness gain, and ΔERIC of handsheets compared to those made from the offset prints. In addition, a certain correlation was found between IEERIC (ink elimination), chemical oxygen demand (COD), and total organic carbon (TOC) of wastewater effluents after recycling of LEP prints and offset prints as well. Organic water pollution parameters (COD and TOC) showed higher values in wastewater after recycling of offset prints compared to recycling of LEP prints.

Phytoremediation of Physico-chemical Parameters in Wastewater Effluents from Car Wash Bays in Yenagoa Metropolis, Nigeria

Surface water pollution through the discharge of untreated wastewater is on the increase globally. Efforts made using conventional techniques had not yielded the needed results. This study was conducted to determine the effectiveness of some native aquatic plants for the removal of some physico–chemical parameters from car wash wastewater effluents in Yenagoa metropolis. The plants used for this study were lemna minor, nymphaea nouchalli, pistia-stratiotes, eichhornia crassipes and ceratophyllum demersum; while the physico-chemical parameters investigated in this study include pH, DO, COD, BOD5, NO3, PO4 and turbidity. The wastewater samples collected from car wash bays were analysed to determine the level of the physico-chemical parameters concentrations using standard methods. The experiment was conducted in a green house for 42 days retention period. The results indicated that the cultured plants reduced the physico-chemical parameters to a minimum level, except DO, which increased in concentration. Therefore, they are considered good bioremediators of the parameters under review and the bioremediation potentials of the plants are in the order of P. stratiotes > L. minor > E. crassipes > N. nouchalli> C. demersum. It is therefore recommended that these plants should be used to treat wastewater effluents based on the investigated physico-chemical parameters.

Synthetic Biology-Based Approaches for Microalgal Bio-Removal of Heavy Metals From Wastewater Effluents

Heavy metal polluted wastewater from industries is currently one of the major environmental concerns leading to insufficient supply of clean water. Several strategies have been implemented to overcome this challenge including the use of microalgae as heavy metal bio-removers. However, there are still limitations that prevent microalgae to function optimally. Synthetic biology is a new biological discipline developed to solve challenging problems via bioengineering approaches. To date, synthetic biology has no universally affirmed definitions; however, it is uncontroversial that synthetic biology utilizes a constructive library of genetic standardized parts to create new biological systems or to redesign existing ones with improved characteristics. In this mini-review, we present state-of-the-art synthetic biology-based approaches that can be used to enhance heavy metal bio-removal from wastewater effluents by microalgae with a narrative synthetic biology workflow (Design-Build-Test-Learn cycle) to guide future developments of more advanced systems. We also provide insights into potent genes and proteins responsible for the bio-removal processes for stepwise developments of more advanced systems. A total of 49 unique genes and proteins are listed based on their eight heavy metals (Mn, Fe, Cu, Zn, As, Cd, Hg, and Pb) bio-removal functions in transport system, cellular tolerance, synthesis of key players in heavy metal bio-removal, biotransformation of heavy metals, and gene expression regulation. Thus, with our library, genetic parts are ready to be recruited for any synthetic biology-based designs. Thereby, this mini-review identifies potential avenues of future research and maps opportunities to unleash more potential of microalgae as heavy metal bio-removers with synthetic biology.

Microbiological Assessment of Elechi Creek Receiving Wastewater Effluents from Industrial Operations in Port Harcourt City

Disposal of wastewater and other effluents into water bodies from activities around water bodies have for long been of major concern and challenge to the environment leading to several infectious diseases. The amount of industrial untreated solid wastes from companies, wastewater from car washing activities, open drainages and agricultural runoffs located close to Elechi creek constitutes the wastewater effluents received by the creek thus resulting in the imbalance of the ecosystem. The study was therefore aimed at determining the microbiology of water quality at different stations of the Elechi creek. Surface water, wastewater and sediment samples were collected during a seven month period and analysed using standard microbiological procedures. Results obtained revealed that the average microbial counts ranged as follows: Total Heterotrophic bacteria 1.12±0.13x108 to 1.28±0.09x108 cfu/ml, Total coliform count; 6.4±0.21 to 7.8±0.13 cfu/ml, Total Staphylococcus Count; 6.9±0.06 to 7.9±0.08 cfu/ml, Total Shigella count; 7.9±0.11 to 8.5±0.14 cfu/ml, Total Salmonella Count; 5.4±0.13 to 7.9±0.08 cfu/ml, Total Vibrio Count; 5.9±0.13 to 7.4±0.09 cfu/ml, and Total Pseudomonad Count; 2.5±0.08 to 4.8 ±0.10 cfu/ml, in surface water, Total Heterotrophic bacteria 1.02±0.08 x108 cfu/ml to 2.68±0.08 x108 cfu/ml, Total coliform count; 4.4±0.10a to 4.9±0.11a cfu/ml, Total Staphylococcus Count;4.7±0.10 to 5.9±0.12 cfu/ml, Total Shigella count; 4.0±0.08 to 4.8±0.11 cfu/ml, Total Salmonella Count; 3.2±0.16 to 4.6±0.08 cfu/ml, Total Vibrio Count; 2.0±0.15 to 4.8±0.11 cfu/ml, and Total Pseudomonad Count2.7±0.13 to 3.9±0.09cfu/ml, in wastewater and Total Heterotrophic bacteria 2.16±0.07 x109 cfu/g to 2.24±0.09 x109 cfu/g, Total coliform count; 1.01±0.13 to 1.36±0.06b cfu/g, Total Staphylococcus Count; 6.8±0.11 to 9.1±0.08 cfu/g, Total Shigella count; 4.0±0.09 to 6.5±0.06 cfu/ml, Total Salmonella Count; 4.1±0.11 to 9.7±0.12 cfu/g, Total Vibrio Count; 6.8±0.10 to 9.5±0.09 cfu/g, and Total Pseudomonad Count; 4.0±0.16 to 5.9±0.07 cfu/g, in sediment samples. Bacterial isolates belonging to the genera Bacillus, Staphylococcus, Enterococcus, Pseudomonas, Proteus, Klebsiella, Providencia, Escherichia coli, Salmonella, Shigella, Vibrio and Enterobacter were isolated and identified. The occurrences of these bacterial isolates as potential pathogens could cause poor water quality through fouling and render the water for various uses and may pose a public health threat to our water resources. Adherence to good hygienic practices and proper treatment of wastewater before discharge into the environment should be encouraged to minimize the spread of infectious diseases and fouling of water bodies. This may also affect the aquatic life in such ecosystems.

Trace Detection and Quantitation of Antibiotics in a South African Stream Receiving Wastewater Effluents and Municipal Dumpsite Leachates

One of the major concerns in the consumption of antibiotics is the discovery of antibacterial resistant genes due to prolonged exposure which makes their presence in environmental samples a priority. In this study, we screened 52 antibiotics along a South African stream polluted with wastewater effluents and municipal dumpsite leachates. Of these antibiotics, 15 were detected in the stream while 3 sulfonamides (sulfamethizole, sulfamethazine, sulfamethoxazole), a fluoroquinolone (flumequine) and a diaminopyrimidine (trimethoprim) were further quantified. The concentrations of sulfamethizole, sulfamethazine, sulfamethoxazole ranged from not detected to 0.133 µg L−1, flumequine ranged from 0.222 to 0.686 µg L−1, while trimethoprim was up to 0.0618 µg L−1. The highest concentrations were recorded at the point source discharge with most antibiotics not detected further downstream. The current study has further confirmed wastewater effluents and dumpsite leachates as pathways of antibiotics into the environment. Only the persistent unsanctioned antibiotic, flumequine had its risk quotient above 0.1 making it an antibiotic of environmental concern. Multiresidue studies are still limited in Africa and the current study offers a platform for a research paradigm shift with more studies expected to emerge providing an improved overview of the release of antibiotics and other pharmaceuticals into Africa’s vulnerable surface water systems.