Assessment of dairy wastewater treatment and its potential for biogas production at Tanga fresh limited

The extent of pollution of dairy wastewater treated in a septic tank and its potential for biogas production was investigated. Performance of the existing treatment system was assessed through characterization of both raw and treated effluents. From the analysis parameters likeChemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Total Suspended Solids (TSS), alkalinity, turbidity, color and phosphorus disclosed inadequate system performance with treated effluent displaying higher values of organic matter than the allowed discharge limits according to the national standards. Optimal conditions for biogas production such as temperature, pH and type of inoculum were determined through batch experiments. The optimum conditions were 35 oC and pH 7.0 with cow dung as inoculum type, which resulted in production of 0.49 m3 of biogas per Kg COD of dairy wastewater. The reduction efficiencies of COD, TS and VS were 98%, 78% and 73%, respectively. Therefore, these conditions can be applied for treatment of wastewater at Tanga fresh limited (TFL) Plant, to ensuring adequate dairy wastewater treatment and recovery of biogas while preventing environmental pollution from the 100 m3 of dairy wastewater produced daily.Keywords: Biogas; dairy wastewater characterization; environmental pollution; treatment condition

Performance of water filters towards the removal of selected pollutants in Arusha, Tanzania.

This paper presents the findings of a study carried out to investigate the efficiency of selected common water filters in the removal of Escherichiacoli, organic matter and fluoride. Additionally, the Total Suspended Solids, Turbidity andcolour were also considered for assessing the performance of the filters in ensuring safe water provision. The results showedthat various filters performed differently at particular retention times. Removal of Escherichia coli, was found to be 100%, 75%, 96%, 96.5, 98.5%forbio-sand, slow sand, ceramic, bone char and membrane purifier respectively. Organic matter removal was found to be 47%, 43%, 53%, 43.4% for bio-sand, slow sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% for bone char filter. Furthermore, filters were also assessed in terms of media availability, buying costs, operation, benefits/ effectiveness towards major pollutants, and drawbacks. The study concluded that filters currently present in the market especially in Arusha are effective towards specific pollutants. To remove multiple pollutants, an integrated filter would be needed for optimized performance.Key words: water filters, water purification, E. coli, organic matter, fluorid

Eggshells – assisted hydrolysis of banana pulp for biogas production

In this study, pretreatment of banana pulp using eggshells in both calcined and un-calcined forms to examine the extent of hydrolysis was conducted. Reactor CO containing banana pulp and inoculum but with no eggshells added was used as the control, while reactors C1, C2, C3, C4, and C5 containing banana pulp and inoculum were spiked with 1, 3, 5, 7, and 9 g of un-calcined  eggshells and calcined eggshells, for experiment 1 and 2, respectively. Anaerobic digestion was carried out at mesophilic  temperature (35°C) for a period of 20 days. Digester C3 with 5 g of calcined eggshells gave the largest cumulative biogas yield of 2343 mL with 62% CH4, follow. The least biogas yield of 10 mL was obtained in digester C5with 9 g of calcined eggshells additive.Key words: Anaerobic digestion, banana pulp hydrolysis biogas, eggshells

Design and Optimization of Sedimentation Tank Coupled with Inclined Plate Settlers as a Pre-Treatment for Ultra-Filtration

Access to clean and safe drinking water is difficult in most rural areas of Sub-Saharan Africa. In most places, the water is generally available during the rainy season, but it is muddy and full of sediments. But in Karatu, regardless of the season, the water is always highly turbid with suspended particles. High turbidity water is a great challenge to water treatment works as it can be hard to remove and also harbors pathogens. Because of a lack of cost-effective purifying agents, communities suffer from water scarcity or indeed drink water that is no doubt contaminated by sediment and livestock/human feces. Unsafe drinking water is a major cause of water-related diseases that predominantly affect people living in developing countries. Today there are many technologies available to treat unsafe water. However, most of such technologies are suited for use with low turbidity source water. Ultra- Filtration (UF) is one technology which is limited to treating high turbidity water. The pre-treatment of high turbidity water (>1000 NTU) is a challenge that was investigated in this research. This paper describes a laboratory scale sedimentation tank coupled with Inclined Plate Settlers (IPS) tested and optimized at Nelson Mandela African Institution of Science and Technology (NM-AIST), to see if, given the local particle sizes and distribution in the earthen dam water of Karatu, IPS can pre-treat the raw water to remove enough turbidity to make UF a feasible option. The results of this work show that IPS is not only a feasible option in pre-treating highly turbid water for the UF (˂ 50 NTU) but also a viable technology in treating water with very high turbidities to within the Tanzania drinking water standards (< 25 NTU). Keywords: High turbidity water; Sedimentation tank; Inclined Plate Settler; Ultra-Filtration; Water suppl

Kinetic analysis of anaerobic sequencing batch reactor for the treatment of tannery wastewater

This research article was published in Academic Journals, Vol.11(6) 2017.A pilot scale anaerobic sequencing batch reactor (ASBR) was operated at different organic loading rate (1.03, 1.23, 1.52 and 2.21 kg.m-3.d-1) in order to determine the chemical oxygen demand (COD) removal and methane production kinetic models. The system was operated at mesophilic temperature. The wastewater was fed using submersible pump in every twenty four hours and agitated with hydraulic pump for fifteen minutes in every one hour. The COD removal efficiencies was found to be between 69-85% and the methane yield was also between 0.17±0.2 and 0.30±0.02 m3/kg COD removed. In the kinetic studies, modified Stover-Kincannon and second-order models were found to be the most appropriate model for ASBR treating tannery wastewater than first order model. The saturation value constant and maximum COD removal rate found in Stover-Kincannon model were 5.57 and 5.56 kg of COD m-3.d-1, respectively. The kinetic studies of volumetric methane production showed that Michaelis-Menten model was found to be capable of predicting the volumetric methane production in ASBR that treat tanney wastewater

Efficacy of waste stabilization ponds and constructed wetlands adopted for treating faecal sludge in Africa: a review

This research article was published in the International Journal of Environmental Health Research,2024The generation of faecal sludge (FS) in capitals and urban settings of African countries outpaces the available storage, emptying, transportation and treatment technologies. The low technology-based treatment systems for handling FS are preferable and widely adopted in the African context due to their less associated investment and operation costs. The waste stabilization ponds and constructed wetlands were principally developed as wastewater treatment systems however they are widely adopted for treating FS in urban settings of Africa. Less information is known about the efficiency of these systems in lowering FS pollutant concentrations to meet the design specifications and the allowable discharge limits. This paper reviewed the technical efficacy of waste stabilization ponds and the constructed wetlands in treating FS by evaluating the actual treatment efficiency data against the design efficiencies and the maximum allowable discharge limits. The review results revealed that these technologies are user-friendly although they fail to lower the solids concentrations to meet the design and maximum allowable discharge limits. This failure imposes extra costs on operation and maintenance due to the fast filling of solids in the systems hence leading to short-circuiting issues. So, studies on the adequate dewatering technologies of FS before entering the systems are needed

Wastewater treatment for reuse in urban agriculture; the case of Moshi Municipality, Tanzania

This research article was published by Pergamon in 2014Urban agriculture is practiced by dwellers as an adaptive response to improve their food security, household income, create informal employment and diversify their livelihood through sales of surplus produce or savings. People in many cities, who practice urban agriculture, are in most cases unemployed and poor and are faced with water shortages to irrigate their crops. But treated wastewater can offer both water and nutrients needed for crop growth partly covering the water shortage already experienced. Therefore in this case, wastewater reuse becomes one of the important alternative ways to provide water for irrigation. The objective of this study was to monitor the effluent quality of the waste stabilization pond (WSP) and a combined WSP-constructed wetland (WSP-CW) treatment systems, assess its suitability for irrigation purposes and understand the public perception on the use of the treated effluent for agricultural production. This paper brings out the experience of the Moshi urban water authority in wastewater treatment and reuse for irrigation purposes. It looks on the quality of effluent from the two systems under their current operational regime and deduces the public health and socio economic implications. The results indicates the recorded TDS mean values of 587 mg/L and 627 mg/L, Nitrate–Nitrogen values of 9.19 mg/L and 2.35 mg/L, Fecal Coliform values of 1000 counts per 100 mL and 4626 counts per 100 mL, COD values of 159 mg O2/L and 149 mg O2/L for the WSP and WSP-CW effluents respectively. From the findings it has been shown that the treated effluent is suitable for restricted irrigation. It has also been shown that when improperly practiced, the use of the effluent is associated with public health risk to the workers who handle it, but despite this fact there is still some positive social economic implications. The community members who practice irrigated agriculture using the effluent as irrigation water have positive attitude on its use. The findings from this case study, is considered as an important learning in establishing an optimal wastewater treatment configuration to render suitable effluent for irrigation purposes

Assessment of agrochemical residues in wastewater from selected horticultural farms in Arusha, Tanzania

This research articles was published by International Journal of Environmental Sciences in 2015Arusha region in Tanzania has been involved for quite some time on commercial horticulture. The use of agrochemicals results to increased crop productivity and consequently offers farmers major economic returns. However, the use of agrochemicals and the adjacency of horticultural farms to streams and rivers have the potential to contribute to water pollution if control measures are not effective. We analysed the physical and chemical parameters of wastewater discharged from selected horticultural farms in Arusha and detected nitrates (NO3-), phosphates (PO43-), sulphates (SO42-) and permethrins insecticide in the effluents discharged into the environment. The mean concentration levels ranged from (4.5 ppm - 64.08 ppm) for NO3-, (3.22 ppm - 47.64 ppm) for PO43-, (91.42 ppm - 139 ppm) for SO42- and permethrin was 0.63 ppm. Of all the farms monitored, eighty percent (80%) had high levels of PO43-, sixty percent (60 %) had high levels of NO3- and twenty percent (20 %) had high levels of permethrin above the allowable limits for discharge into receiving water resources. It may be concluded that the continued agrochemical use may lead to contamination of adjacent water resources which may in the long run cause adverse health effects to the downstream water users. Continual monitoring of agrochemical residues is recommended to inform and ensure compliance with the stipulated standards and regulations for wastewater dischar

Fabrication of porous carbon nanofiber webs from polyacrylonitrile and cellulose acetate for NaCl removal from water using capacitive deionization

This research article was published by IWA, 2024Capacitive deionization (CDI) has shown potential in addressing freshwater scarcity. CDI's electrode design is a key to better performance as it determines the extent of water purification. For carbon electrodes, the pore structure is an important factor influencing removal kinetics and ion storage. Herein, porous carbon nanofibers with diameters ranging from 277 to 348 nm were fabricated from blends of polyacryloni- trile (PAN) and cellulose acetate (CA) through electrospinning and carbonization. Surface area and pore properties were adjusted by varying the proportions of the precursors while ensuring no adverse alteration to the products’ tangible properties. Enhanced pore structure and specific surface area were evident in the blend-based carbon nanofibers. The blend ratio of 2:8 (CA:PAN) had a high specific surface area of 925.47 m2 /g and a pore volume of 0.7884 cm 3 /g. Correspondingly, a high specific capacitance of 177.5 F/g was attained. Desalination per- formance was determined in batch mode using 500 mg/L NaCl solution. A salt adsorption capacity of 6.57 mg/g and charge efficiency of 0.46 was obtained for the blend that had 20% CA. The carbon nanofibers demonstrated good desalination stability when used repetitively indi- cating their excellent potential for practical applicatio

Optimization of Sedimentation Tank Coupled with Inclined Plate Settlers as a Pre-treatment for High Turbidity Water

Access to clean and safe drinking water is a challenge in most rural areas of Tanzania. Unsafe drinking water is a major cause of water-related diseases that predominantly affect people living in developing countries. In most places, water is readily available during the rainy season, but it is muddy and full of sediments. But in Karatu, regardless of the season, water is always highly turbid with suspended particles. High turbidity water is a great challenge to water treatment works as it can be hard to remove and also harbors pathogens. Because of a lack of cost-effective purifying agents, communities suffer from water scarcity and use water that is no doubt contaminated by sediment and livestock/human feces. Today there are many technologies available to treat unsafe water. However, most of such technologies are suited for use with low or no turbidity source water. Ultra- Filtration (UF) is very effective in making unsafe water safe through removal of chemical species and pathogens. UF, however, like many other treatment techniques, is limited to treating water with high turbidity. Pre-treatment is needed. The pre-treatment of high turbidity water (>1000 NTU) is a challenge that was investigated in this research. This paper describes a laboratory scale sedimentation tank coupled with Inclined Plate Settlers (IPS) tested and optimized at NM-AIST, to see if IPS can pre-treat the raw water to remove enough turbidity to make UF a feasible option. The results of this work show that IPS is not only a feasible option in pre-treating highly turbid water for the UF (˂ 50 NTU) but also a viable technology in treating water with very high turbidities to within the Tanzania drinking water standards (< 25 NTU). The design is ready for pilot testing in field environment. Keywords: High turbidity water, Sedimentation tank, Inclined Plate Settler, Ultra-Filtration