Simple and Cost-Effective Biomonitoring Method for Assessing Pollution in Tropical African Rivers

Adoption rule whereby tropical African regions rely on non-tropical biomonitoring methods to assess water pollution in their rivers has been hindered by geographical incompatibility due to environmental variations between the regions that affect the capability and reliability of adopted method. Likewise, inclusion of all identified macroinvertebrate assemblages in developing the existing biomonitoring methods (i.e., South African Scoring System (SASS5) and Tanzania Riverine Scoring System (TARISS)) has made them complex taxonomically as their use requires users of greater expertise and much time during taxa identification. Such taxonomic complications and conflicting aspects regarding the adoption or modification of non-tropical biomonitoring methods in developing tropical biomonitoring methods have therefore necessitated the design of this study in order to develop simple and cost-effective tropical African biomonitoring methods, for initial application in Tanzanian rivers. Six pairwise screening criteria were employed to select orders with distinctive potential for inclusion in developing simple and cost-effective biomonitoring method. Only Ephemeroptera, Diptera, Odonata and Trichoptera (EDOT) orders met all six inclusion criteria after showing their ability to discern reference sites from monitoring sites and correlating strongly with environmental variables. Being developed using only four diverse orders with the wider range of occurrences and sensitivity to pollution, the EDOT method will minimize data variability, the need for greater expertise, cost, and time during taxa identification. The novelty of the present approach lies on the simplification of the taxonomic complication that is inherent in existing indices for four decades and modelling application to simulate sensitivity weightings for taxa with unknown sensitivity score ratings.

Effectiveness of Macroinvertebrate Species to Discern Pollution Levels in Aquatic Environment

The World is transforming more rapidly than ever before as a result of urbanization and industrialization. Such unrelenting destruction of nature has surpassed the capacity of mother Earth to support the aquatic ecosystem. Apart from freshwater macroinvertebrate species, there is no single measure of declining freshwater ecosystem that can capture either the short and long-term changes or the trend of overall freshwater ecosystem health. In that regard, the macroinvertebrates and physico-chemical variables were used as surrogates to determine levels of impairment within and between Pangani and Wami-Ruvu rivers’ basins in Tanzania. Spatial distribution of macroinvertebrate communities in the basins is significantly influenced by varying levels of environmental variables as a result of geomorphology and improper land uses. Principal Components Analysis (PCA) ordination showed two distinct patterns of biometrics that clearly discriminate reference sites from monitoring sites at each basin and consequently demonstrate the differences in water quality and physical habitat between the site categories. Similarly, distinctive macroinvertebrate species were observed and varied considerably among the site categories in the studied rivers as a function of tolerance levels. Impacted sites are characterized by either absence of any sensitive taxa or presence of few if any;greater dominance of only a few taxa that are tolerant to pollution. Therefore, the more diverse orders with a wider range of occurrences and tolerance to pollution (Ephemeroptera (E), Diptera (D), Odonata (O) and Trichoptera (T)) can be considered as potential bio-indicators in developing biomonitoring index for Tropical African Rivers as they showed a significant discriminating power that separated reference from monitoring sites.

Technical and technological constraints facing Tanzania leather value chain:a snapshot of intervention measures

The leather value chain starts with livestock, the key source of hides and skins, and the main raw materials for the industry. Despite having the second-largest livestock population in Africa, Tanzania is only the 11th largest exporter of leather on the continent, underlining the disproportionate contribution of the sector to the economy. This study presents the results of a recent assessment aimed at identifying performance bottlenecks in Tanzania’s leather sector. The assessment took place in October-December 2020 and involved 10 tanneries, 30 leather goods factories and 11 service providers/institutions. Findings reveal that 90% of tanneries are dissatisfied with the quality of hides and skins due to brand marks, flay cuts, skin diseases, and inadequate curing. These supply chain bottlenecks are further compounded by skill deficiencies among processors, poor waste management, and limited awareness about laws, policies and regulations governing trade in the sector. At the downstream end of the value chain, the trade in leather and related articles is facing competition from high importation of low-grade products like plastic shoes and second- hand products. This paper recommends that efforts to increase leather’s economic and trade value need to focus on upgrading Tanzania’s production, processing, branding and marketing capacities.

Study on Biomass Gasified Generator Using Rotary Engine

The purpose of this study is to investigate the biomass gasification system for power supply to introduce in rural communities of developing countries.The study was conducted using biomass gasification system(20 kW)which developed at Ashikaga University.In general,for small scale power supply system using biomass gasification,reciprocate type engine or modified diesel engine are attached for power generation.However,biomass gasifier produces tar and it causes problems on smooth movement of piston in the reciprocate engine.To avoid effect by tar,the system is comprised the rotary engine coupled to a generator since there is no piston inside the engine.As for gasification system,downdraft gasifier is designed and installed.In this study woody biomass was gasified.The gasifier performance was evaluated with respect to fuel consumption rate.The rotary engine-generator system was evaluated in terms of power generation efficiency.Result of this study shows that fuel consumption rate was about 30 kg/h,gasification efficiency was about 63.4%and efficiency of rotary engine system was about 9.4%.

Experimental study on modification of water-based filtercake to improve the bonding strength at the wellbore cement-formation interface

The objective of this experimental study is to improve the cementing bond quality of sandstone oil-gas well along the wellbore cement-formation interface(WCFI),so as to ensure long-term zonal isolation throughout the lifecycle of the well by using NsO solution as filtercake modifier which was developed in the laboratory.According to designed experimental method and API RP 10,the effectiveness of filtercake modifier(NSO)on the bonding strength at the WCFI was assessed by using designed simulated wellbore as sandstone formation.The experimental results indicated that the samples which were treated with NsO solution had higher bond strength over untreated samples.The strength generally increased with curing period as for treated samples,0.198,0.374,0.433 and 0.473 MPa for 3,7,15,and 30 days respectively while for the untreated samples the bond strength were 0.050,0.070,0.81 and 0.100 MPa for the same period.The water-based filtercake modification techniques had significantly enhanced the bonding strength of WCFI by increasing rates above 296%.Improvement of bond strength to the treated sample was due to filtercake modification as a result of formation of cementitious material as revealed in FTIR spectral such as Calcium-Silicate-Hydrate(C-S-H)and other geopolymers like Calcium-Aluminium-Silicate-Hydrate(C-A-S-H)and Sodium-Aluminium-Silicate-Hydrate(N-A-S-H)along the interface which filled the existed pores hence reducing porosity hence high strength of bond.The low transmittance value for the NsO treated samples revealed that there were more cementitious materials existing at the WCFI which led to improvement of bonding strength as compared to the untreated samples.The lower/poor bond strength for the untreated samples is due to existence of untreated,thick water-based filtercake films at WCFI,which prevented the complete hydration process between rock grains and cement slurry components to make chemical binder of cement slurry material and formation.2022 The Authors.Publishing services provided by Elsevier B.V.on behalf of KeAi Communication Co.Ltd.This is an open access article under the cc BY license(http://creativecommons.org/licenses/by/4.o/).

Tanning capacityof Tessmannia burttii extracts:thepotentialeco-friendlytanning agents fortheleatherindustry

In the present study,the tannins from stem and root barks of Tessmannia burttii Harms(Caesalpiniaceae),a plant species abundantly growing in Tanzania and other parts of Africa,were investigated for their suitability in hides tanning.Tannin powder was extracted at selected temperatures(30,50 and 80°C)and the influence of each temperature on the crosslinking capacity was evaluated.The interaction mechanism between hide powder collagen and the tannins was studied by Differential Scanning Calorimetry(DSC),trinitrobenzensulfonic(TNBS)acid assay and amino acid hydrolysis methods.Extraction temperatures showed low influence on crosslinking capacity of the tannins.However,extract obtained at 50°C exhibited best performance in terms of gap size between T onset and T peak.The stem bark extract yield was higher than that from the root bark,but both were within the recommended ranges.The tannin content(61%)of T.burttii stem bark extract was above recommended value(10%),whereas its total phenolic content and total flavonoic content were found to be above that of commercial Acacia mearnsii tannin.The study of cross-linking parameters as a function of pH showed cross-linking to occur via a covalent mechanism at the basic amino groups.However,the bonds were not resistant to acid hydrolysis.The observed interaction mechanism indicated that tannins from stem and root barks of T.burttii belong to the condensed tannin,similar to A.mearnsii(black wattle),a commercial tannin source that was used in this study as a reference.Findings from this study depict that T.burttii extracts are auspicious eco-friendly alternative source of vegetable tannins to overcome the use of chromium salts in the leather industry.