Evaluation of initial pH and urea hydrogen peroxide (UHP) co-pretreatment on waste-activated sludge.

Wastewater treatment and conversion into renewable energy sources have been of great interest in recent times due to growing environmental pollution concerns and need for sustainable energy sources. Sewage sludge treatment can convert sludge into renewable energy. In this study, the impact of initial pH and urea hydrogen peroxide (UHP) co-pretreatment on sludge hydrolysis and anaerobic digestion was investigated. The pH of sludge was initially adjusted to 7, 9, and 11 before the addition of 8 mmol/g VS UHP. Under 24 h pretreatment, alkaline medium and UHP effectively enhanced sludge solubilization and hydrolysis. The combination of chemical, sonication, and centrifugation improved the extraction of extracellular polymerase substances released in soluble state. Secondly, anaerobic digestion was performed for 11 days to determine the influence of a lower mesophilic temperature (20 °C) and retention time on the pretreated sludge. The highest NH4+-N concentration of 5.32 g/L was recorded in pH 7+UHP. The most significant total VFA concentration of 13.1 g COD/L was observed in pH 7+UHP on day 9. Acetic acid, isovaleric acid and propionic acid accounted for 80%-83% of the total VFA composition in all pretreated reactors. Lower mesophilic temperature efficiently optimized UHP and VFA production in the pretreated reactors. Microbial metabolism was stabilized under a longer retention time. Alkaline pH and longer retention time elevated NH4+-N and VFA concentration. The results showed that initial pH and UHP co-pretreatment of waste activated sludge offer an alternative pathway for enhancing sludge hydrolysis and VFA production applicable in sludge treatment.

Physical activity interventions implemented for older people in sub-Saharan Africa: protocol for a scoping review.

INTRODUCTION: The global population of older people (OP) is on an upward trajectory, with predictions that the number of OP would surpass the population of younger people by 2050. In sub-Saharan Africa (SSA), death from infectious diseases in the younger population and lower fertility rates are influencing a double burden contributing to an exponential growth in the ageing population. Non-communicable diseases (NCDs) are the leading cause of mortality and disability in the population of OP in SSA. Physical activity (PA) has been proven to have positive benefits in reducing the prevalence of NCDs in OP. The objective of this scoping review is to summarise the evidence on the feasibility and effectiveness of PA interventions that have been implemented among OP to address PA levels, blood pressure, blood glucose levels, cognitive function, quality of life and body mass index in SSA. METHODS AND ANALYSIS: The Joanna Briggs Insitute (JBI) methodology will be followed for this scoping review. An electronic search of PubMed, EBSCOhost (Academic Search Premier AfricaWide Information, CINAHL, Health Sources Premier Academic/Nursing), Scopus and ProQuest (grey literature) will be done from 2010 onwards to identify reports of randomised controlled studies published in English using relevant keywords. 2010 was selected as the cut-off point for inclusion in order to focus only on relatively recent evidence, as it is more likely to remain relevant and applicable to present-day settings. The searches will be performed by the primary reviewer in conjunction with a senior librarian. Full independent review of the uploaded articles will be done by two reviewers, by title and abstract, and thereafter by full text, based on specified inclusion and exclusion criteria. The reference list of included articles will be scanned for additional relevant articles. Disagreements will be arbitrated by a third reviewer. Results will be presented in a descriptive form as well as in tabular, graphical and diagrammatic formats, following the Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews. ETHICS AND DISSEMINATION: The review will be extracting and reporting on data from published literature so there is no requirement for ethics approval. The findings of the review will be submitted for publication in a peer-reviewed journal.

Contamination status of arsenic in fish and shellfish from three river basins in Ghana.

Fish and shellfish are regularly consumed and sold in Ghana, yet studies on arsenic pollution in Ghana are limited largely to ground water. This study evaluated arsenic concentrations in seven species of shellfish and 10 species of fish inhabiting the mouth of Ankobra, Densu and Volta basins in Ghana and assessed the public health implications. Arsenic levels varied from 0.2 to 2.2 mg L-1 in the three rivers and were higher than WHO recommended values of 10 µg L-1 for drinking water. Except for Periophthalmus sp. and Tympanotonus fuscatus from the Ankobra in which arsenic was not detected, concentrations in the organisms ranged from 0.2 to 2.8 mg kg-1. The maximum quantities of the organisms considered safe for consumption ranged from 375 to 5250 g per week. Caution however needs to be exercised as PTWI for arsenic needs revision, and some heavy metals such as mercury are more toxic than arsenic.

High levels of mercury in wetland resources from three river basins in Ghana: a concern for public health.

Crustaceans, mollusks, and fish are wetland resources that constitute an important source of protein and foreign exchange for the Ghanaian population, and many species of these are sold in the open market and restaurants, yet studies on their heavy metal contents are generally scarce. This paper evaluates the levels of mercury in five species of crustaceans, two species of mollusks, and ten species of fish inhabiting three river basins with different catchment activities in Ghana. These include the Ankobra Basin, characterized with mining and agriculture, Densu Basin, associated with urban waste discharges and agriculture, and Lower Volta River Basin, associated with agricultural activities. Mercury concentration was highest in Ankobra (2.5 ± 2.59 µg g-1) followed by Densu (1.75 ± 1.35 µg g-1) and Volta (0.74 ± 1.46 µg g-1). The mercury load of the organisms range from <0.1 to 4 µg g-1 with the highest load in Cynoglossus senegalensis at Ankobra. Except for Panaeus notialis from Densu and Ankobra, and three other species from Ankobra (Tympanotonus fuscatus, Cardisoma armatum, Callinectes amnicola) in which mercury was not detected, mercury loads of all the organisms were above the permissible limit of 0.5 mg kg-1 established by Commission Regulation-EC (2006) for fishery products and muscle meat of fish. Weekly quantities of crustaceans and mollusks considered safe for consumption by adults ranged from 88 and 1000 g while that of the fishes were between 70 and 700 g (on a dry weight basis) depending on the species. It was clear that some caution needs to be exercised in the consumption of Ghana's fresh and brackish water fisheries.

The concentrations of five heavy metals in components of an economically important urban coastal wetland in Ghana: public health and phytoremediation implications.

Sakumo II is an urban wetland and a receptacle for domestic and industrial wastes from two cities in Ghana. It however supports viable populations of fish and crabs, is cultivated for food crops and grazed by farm animals. Components of the wetland can therefore accumulate pollutants, but the public health and phytoremediation implications of this are yet to be evaluated. We analysed Cd, As, Hg, Cu and Pb in the lagoon water, sediment, green algae, eight species of aquatic macrophytes, seven species of arthropods and one species of fish. The concentrations of Pb were generally below detection limit whilst Cu was detected only in the lagoon water and Pheropsophus vertialis. Cadmium ranged from 21 ± 4 ppb in algae to 69 ± 12 ppb in Typha domingensis and was generally higher than As and Hg. The highest concentration of As was 11.7 ± 2.1 ppb in Pistia stratiotes whilst Hg was highest in lagoon water (4 ± 2 ppb). The Cd concentrations generally, and Hg concentrations in macrophytes, were higher than US EPA guidelines indicating the wetland's resources were unsafe for regular consumption. Among the emergent aquatic macrophytes, T. domingensis, Ludwigia sp. and Paspalum vaginatum, respectively, had the highest accumulation capacity for Cd, As and Hg, but the floating aquatic plant P. stratiotes appeared to be a better accumulator of Cd and As.