Browsing by Author "Bidu, Jerome"

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Current status of textile wastewater management practices and effluent characteristics in Tanzania
(IWA Publishing, 2021-04-05) Bidu, Jerome; Van der Bruggen, Bart; Rwiza, Mwemezi; Njau, Karoli
Textile wastewater from wet processing units is a major environmental problem. Most chemicals, including dyes, are only partly consumed, resulting in highly colored wastewater containing a variety of chemicals released into the environment. This paper gives information on the current management of textile wastewater in Tanzania. A semiquantitative analysis was done to identify the main types of chemicals used in wet processing units, wastewater characteristics and existing wastewater treatment methods in the textile industry. The performance evaluation of the existing wastewater treatment plants is also discussed. The advantages of integrating constructed wetlands with the existing treatment facilities for textile wastewater are explained. It has been observed that pretreatment and dying/printing of the fabrics are the main two processes that produce wastewater in many textile companies. Main pollutants are chemicals used from pretreatment and materials removed from de-sizing, bleaching and scouring processes. Dyes, printing pigments and dye auxiliaries are the main pollutants from the dyeing/printing process. Most of the textile companies in Tanzania are equipped with effluent treatment plants. Wastewater treatment plants have basically similar units, which are coagulation-flocculation, sedimentation through clarifiers and aerobic reactor. However, their effluents do not meet discharge limits stipulated by the Tanzania Bureau of Standards (TBS).
Dust exposure and its health implications to miners in Mererani artisanal and small-scale mining industry
(Taylor & Francis, 2025-01) Mumba, Edward; Selemani, Juma; Kasambala, Hildegard; Bidu, Jerome; Ripanda, Asha; Rwiza, Mwemezi
This study aimed to identify and quantify the total dust exposure to underground miners in Mererani, Tanzania, and its composition to generate evidence for informed decision- and policy-making. The Analytical Air Monitoring System (AMS) was used for dust collection, and analysis was conducted gravimetrically. The dust composition was analysed using Inductively Coupled Plasma Optical Emission Spectroscopy. The results showed significant variation in dust exposure levels across different mining zones, with miners inhaling up to 1859 mg of dust over an 8-hour period in drilling zones (DZ), 797 mg in loading zones (LZ), and 382 mg in resting zones (RZ). The mean value of dust exposure was significantly different, with a p-value of <0.05. Miners had higher levels of heavy metal and silica than those from unmined sites, with chromium being the most dominant element across all samples. Cumulative exposure to dust over time is linked to long-term respiratory impairment and serious health conditions such as lung cancer. These findings highlight the need for intervention, including education on dust hazards, provision of personal protective equipment (PPE), and enforcement of safety standards to safeguard miners’ health. Addressing these issues is critical to promoting policy reforms and sustainable mining practices in Mererani and similar communities.
Improving biological treatment of textile wastewater
(IWA Publishing, 2022-01-01) Laizer, Alpha; Bidu, Jerome; Selemani, Juma; Njau, Karoli
Textile industries are among the primary contributors of water pollution. Treatment of textile wastewater is very important before discharging it to the environment. In the present study, laboratory-scale anaerobic batch reactors were used for co-treatment of a mixture of textile and domestic wastewater at 37 °C. The objective of this work was to investigate optimum conditions for the anaerobic co-digestion of textile wastewater and domestic wastewater. Domestic wastewater as a carbon source to enhance treatment of textile wastewater in color and other pollutants removal was examined. Textile and domestic wastewater were mixed at different proportions to make a total volume of 500 mL. Proportions of domestic wastewater and retention time were two main factors studied in influencing pollutant removal efficiency. Optimum conditions for removal of pollutants were 18 days' residence time at 60 and 40% textile and domestic wastewater respectively. The removal efficiencies were 52.8, 58.3 and 51.6% for Color, BOD and COD, respectively. Phosphorus (PO43−), Ammonium (NH3-N) and Nitrate (NO3-) increased at 78.5, 49 and 87% respectively. However, the concentration levels were above Tanzania Bureau of Standards (TBS) discharge limits. Post treatment is suggested to achieve standard discharge limits.
Textile wastewater treatment in anaerobic reactor: Influence of domestic wastewater as co-substrate in color and COD removal
(Elsevier, 2022-10-28) Bidu, Jerome; Njau, Karoli; Rwiza, Mwemezi; Bruggen, Bart
Treatment of textile wastewater with domestic wastewater as co-substrate was investigated in this study. Combined textile and domestic wastewater at different mixing ratios (100:0, 80:20, 60:40) was treated under anaerobic reactor. The influence of residence time, textile wastewater fraction and initial pH were determined in view of COD and color removal. Response Surface methodology (RSM) with Box–Behnken design (BBD) was employed to determine conditions for higher simultaneous removal of COD and color. The highest simultaneous removal of COD and color were satisfied at initial pH of 8.6, residence time of 9 days while textile and domestic wastewater ratio was 77:23. The highest removal efficiencies realized were 70% and 72% for color and COD respectively. In general, longer residence time and higher initial pH favored higher simultaneous removal of COD and color. Furthermore, textile wastewater fraction in range of 0.65 – 0.8 favored simultaneously high COD and color removal. Therefore, co-digestion of textile and domestic wastewater at specific ratio is a novel finding that can be further developed for treating textile wastewaters. Moreover, this technology is a promising approach to enhance biological treatment of textile wastewater.