Browsing by Author "Manyuchi, Musaida Mercy"

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Biogas Production from Saw dust using Acti-zyme as Digestion Catalyst and its Upgrading to Bio methane using Chemical Absorption
(World Energy Council Congress, 2016-01-01) Manyuchi, Musaida Mercy; Bobo, Arthur. E.; Ikhu-Omoregbe, Daniel I. O; Oyekola, Oluwaseun O.
Zimbabwe has one of the largest deposits of timber in Southern Africa (about 500 000 tons per annum) such that most entrepreneurs venture into timber processing. The venture results in generation of a lot of sawdust dumps that are of no economic use if they are left lying around. There is 10000 metric tons that go to waste each year which when bio-converted can result in biogas. This paper therefore presents the potential for biogas production from saw dust bio-catalysed by Acti-zyme a biocatalyst to enhance the digestion hence biogas yield. This paper presents the bio-catalysed digestion of 4000 metric tons of saw dust per year to produce biogas using Acti-zyme. The generated biogas is then upgraded using chemical absorption for removal of carbon dioxide so as to increase the bio methane energy efficiency. Biogas produced was approximately 24 m 3 per day and was upgraded to 97% from 72% bio-methane composition per day using chemical scrubbing technique in an absorption column. The absorption column design considerations are also presented as well as its process control and the hazard analysis. These are essential in the optimal upgrading of the biogas. Purified bio methane has a higher calorific value of 99 % relative to the 77 % of raw biogas. An economic analysis showed that a 2 year payback period with a return on investment of 48% and break even sales at $331 580.00 with the upgraded bio methane being sold at $2.50/kg. The conversion and upgrading of biogas produced by anaerobic digestion using Acti-zyme is technologically, economically and environmentally feasible.
BIOLOGICAL NUTRIENT REMOVAL FROM MUNICIPAL SEWAGE USING ACTI-ZYME: RECOVERING BIOGAS AND BIO-SOLIDS FROM SEWAGE SLUDGE
(Cape Peninsula University of Technology, 2016-02-05) Manyuchi, Musaida Mercy
Water scarcity is a global problem hence the need for sustainable wastewater management. Sewage, a form of wastewater is being disposed-of to river bodies untreated. Additionally, disposal of sewage sludge, a by-product from the sewage treatment process, is resulting in landfilling problems. This study focused on the sustainable anaerobic treatment of sewage, coharnessing biogas and bio-solids as value added products utilizing Acti-zyme, an enzyme biocatalyst through bio-augmentation. Emphasis was given to the optimum sewage treatment conditions for removal of bio-nutrients, biogas and bio-solids generation, kinetic and statistical modelling of the bio-nutrient removal in sewage as well as the biogas and bio-solids production from sewage sludge. A techno-economic analysis was then done to check the viability of applying this technology on a large scale. The biochemical properties for Acti-zyme were characterized for potential use in anaerobic sewage treatment with the aim of producing biogas. Acti-zyme was then used for sewage treatment at a temperature of 37 °C, agitation rate of 60 rpm, Acti-zyme loadings of 0-0.070 g/L and retention times of 0-60 days. The total Kjeldahl nitrogen (𝑇𝐾𝑁), biochemical oxygen demand (𝐵𝑂𝐷5), total suspended solids (𝑇𝑆𝑆), total dissolved solids (𝑇𝐷𝑆), electrical conductivity (𝐸𝐶), 𝑝𝐻, chloride ions concentration (𝐶𝐼 −), total phosphorous (𝑇𝑃), sulphate ions concentration (𝑆𝑂4 2−), dissolved oxygen (𝐷𝑂) and the chemical oxygen demand (𝐶𝑂𝐷) of sewage were measured using standard methods. The bio-nutrient removal ratios from the sewage were determined and statistical modelling was carried out for the bio-nutrient removal ratios: The 𝐶𝑂𝐷⁄𝐵𝑂𝐷5, 𝐵𝑂𝐷5⁄𝑇𝐾𝑁, 𝐶𝑂𝐷/𝑇𝐾𝑁 and the 𝐶𝑂𝐷/𝑇𝑃. The sewage sludge was anaerobically digested using Acti-zyme in order to obtain biogas and bio-solids. Sewage sludge loading of 5-10 g/L.d and mesophilic and thermophilic temperatures of 37 °C and 55 °C were applied. The biogas quantity produced was measured using the water displacement method. Samples of the biogas were analysed for bio-methane (𝐶𝐻4), carbon dioxide (𝐶𝑂2) and traces gases composition using gas chromatography. The bio-solids obtained were tested for nitrogen, phosphorous and potassium (𝑁𝑃𝐾) content using 𝑢𝑣 − 𝑣𝑖𝑠 spectrophotometry. Kinetic modelling was carried out in MATLAB R2013A to simulate bio-methane production from sewage sludge. Statistical models for anaerobic sewage sludge digestion for generation of biogas and bio-solids utilizing Acti-zyme, were then simulated from the experimental data. SPSS Statistics 19.0 was used as the statistical modelling package at a p-value of 0.05. Capital budgeting techniques were then used for techno-economic assessment of sewage treatment recovering biogas and bio-solids. vii | P a g e D T e c h C h e m i c a l E n g i n e e r i n g Acti-zyme was found to be immotile and contained catalase, proteolytic enzymes and amylase. Acti-zyme did not promote 𝐻2𝑆 production, making it useful in sewage treatment producing biogas. Sewage treatment using Acti-zyme resulted in >60% decrease of the sewage contaminants through bio-augmentation. Optimum sewage treatment conditions were obtained at 0.050 g/L Acti-zyme loading and retention time of 40 days. The 𝐶𝑂𝐷⁄𝐵𝑂𝐷5, 𝐵𝑂𝐷5⁄𝑇𝐾𝑁, 𝐶𝑂𝐷/𝑇𝐾𝑁 and the 𝐶𝑂𝐷/𝑇𝑃 ratios obtained were > 1.2, 4.0, 8.0 and 15.0 respectively. The 𝐶𝑂𝐷⁄𝐵𝑂𝐷5, 𝐵𝑂𝐷5⁄𝑇𝐾𝑁, 𝐶𝑂𝐷/𝑇𝐾𝑁 and the 𝐶𝑂𝐷/𝑇𝑃 bio-nutrient removal models were developed. Optimum biogas production was obtained at a sewage sludge loading of 7.5 g/L.d and Acti-zyme loading of 0.050 g/L with a 78% bio-methane composition was achieved at mesophilic temperatures of 37 °C. Bio-solids with 8.17, 5.84 and 1.34 % of 𝑁𝑃𝐾 respectively were produced. The bio-methane production was simulated to the linear, exponential, logistics kinetic, exponential rise to a maximum, first order exponential model and the modified Gompertz kinetic models. The logistics kinetic model accurately simulated the bio-methane production with a k-value of 0.073 day-1 . Furthermore, linear, quadratic, compound and exponential statistical models were tested and validated for the biogas and the bio-solids generation. The quadratic statistical models were significant for simulating biogas and bio-solids production respectively. A sewage plant with a capacity of 19.6 600 ML/day was considered for techno-economic assessment, with an operating efficiency of 60% and a life span of 20 years. $5.125/day of Actizyme were required for production of 12 769.69 kg/day for biogas costing $1.50/kg and 672.08 kg/day of bio-solids costing $16.00/50kg. A net benefit of $5 656 363.92 per annum for using the Acti-zyme technology in sewage digestion was forecasted, whilst a net energy of 1 387.33 KWh was set to be produced. An investment of $22 199 501.40 was required for kick-starting the project. A positive net present value of $1 186 239.23 was realized with an internal rate of return of 17.6% and a payback period of 5.9 years. For breakeven to be realised, only 183 059.16 KWh must be produced. The techno-economic assessment indicated it is viable to treat sewage using Acti-zyme as bio-augmentation catalyst; co-harnessing biogas and bio-solids as valued added products to an extent of contributing 0.04% to the Zimbabwe gross domestic product.
Biosorbents for the removal of synthetic organics and emerging pollutants: Opportunities and challenges for developing countries
(Environmental Development, 2016-05-23) Chaukura, Nhamo; Gwenzi, Willis; Tavengwa, Nikita; Manyuchi, Musaida Mercy
Contamination of aquatic systems by synthetic organic contaminants and emerging pollutants poses significant public and environmental health risks in developing countries. These contaminants mainly originate from textile, agrochemical, and pharmaceutical industries. The removal of such contaminants is problematic in developing countries because advanced water treatment methods are still lacking in developing countries due to their high costs. The application of biosorption for removal of organic contaminants in developing countries is attractive for three reasons; (1) large quantities of biomaterials for use as biosorbents are readily available; (2) lack of advanced water and wastewater treatment systems for removal of organic contaminants; and (3) the technology is relatively cheap compared to advanced methods (e.g. membrane filtration) often used in developed countries. Overall, this has the potential to remove organic contaminants from aqueous systems while simultaneously reducing the public health and environmental impacts associated with the disposal of such biowastes. However, large-scale application of biosorption faces potential challenges including lack of funding, poor mechanical properties of biosorbants, complex adsorption mechanisms involved, and poor regeneration capacity. In addition, spent biosorbents present an environmental risk and their disposal is problematic due to the potential of contaminating surface and ground water. Possible disposal methods for spent biosorbent include use as a filler in road surfacing, as a soil amendment, and in phytoremediation cells where the organics are absorbed and broken down by plants. Overall, biosorption is a potentially viable alternative, but further research on its ability to remove pollutants from multi-component systems, its regeneration capacity, and plant design parameters is required before the benefits of the technology are realised in developing countries.
Continuous flow-through vermireactor for medium scale vermicomposting
(Asian Journal of Engineering and Technology, 2013-04-01) Manyuchi, Musaida Mercy; Chitambwe, Trymore; Chigumo, Michelle T. C.; Phiri, Anthony; Muredzi, Perkins; Kanhukamwe, Quinton
Vermicomposting is increasingly becoming popular as an organic waste management technology whereby earthworms feed on the organic waste to produce vermicasts and vermiwash. Several vermireactors have been used for this process as batch systems. However, there is need to design a continuous flow-through vermireactor which allows the simultaneous addition of the organic waste at the same time harvesting the vermicasts. A 5m X 2m X 1.5m vermireactor was proposed to process an initial feed of 7 500kg. A 10cm thick bedding comprising of office paper, card board paper and Eisenia fetida earthworms stocked at 1kg/m2 of the vermireactor was used as an initial bedding. The feed bed was 20cm thick and comprised of paper, cow dung, corn pulp and vegetables. The pH, temperature and moisture content in the vermireactor ranged between 5.5-7.5, 19-25°C and 28-52% respectively. 7kg/day of vermicasts were produced given the earthworms produced 75% of their bodyweight as vermicasts per day. The caked vermicasts were expelled by the aid of a breaker bar. The vermireactor was constructed from polyvinyl chloride. Vermicasts containing nitrogen (4.19%), phosphorous(1.15%) and potassium (6.18%) were obtained. The continuous flow-through vermireactor design allowed the production of stable vermicasts and can be used in medium scale vermicomposting.
Effect of Vermicompost, Vermiwash and Application Time on Soil Micronutrients Composition
(International Journal of Engineering and Advanced Technology (IJEAT), 2013-06-03) Manyuchi, Musaida Mercy; Phiri, Anthony; Muredzi, Perkins
Vermicomposting is increasingly becoming popular as an organic solid waste management strategy. The technology results in two bio-fertilizers, vermicompost and vermiwash. The bio-fertilizers were applied to the soil and their impact on the soil micronutrients time was quantified. A maximum of 1000g of vermicompost and vermiwash was applied over 40 days. 23 factorial designs were used to determine the effects of the bio-fertilizers and application time on the soil micronutrients. Increasing the vermicompost quantity resulted in increased soil zinc, manganese and iron content. Increased vermiwash quantities resulted in increased soil iron content but resulted in decreased copper content. Furthermore, increased application time of the two bio-fertilizers resulted in enhanced soil copper and iron content but decreased the zinc and manganese content. The loam-clay soil, organic material from the bio-fertilizers and microbial activity played a significant role in altering the soil micronutrients.
Effect of Vermicompost, Vermiwash and Application Time on Soil Physicochemical Properties
(International Journal of Chemical and Environmental Engineering, 2013-08-01) Manyuchi, Musaida Mercy; Chitambwe, Trymore; Phiri, Anthony; Muredzi, Perkins; Kanhukamwe, Quinton
Vermicomposting results in the production of two bio-fertilizers, vermicompost and vermiwash. The bio-fertilizers were applied to 4kg of loam-clay soil over a period of 40 days. The effect of the vermicompost, vermiwash, application time and their combined effect on soil pH, electrical conductivity and nitrogen, phosphorous and potassium content were analyzed. Increasing the vermicompost quantity decreased the soil pH, electrical conductivity and nitrogen content, however, this resulted in a slight increase in the phosphorous content but the potassium content remained unaltered. Increasing the vermiwash quantity increased the soil pH, electrical conductivity and potassium content but resulted in reduced nitrogen and phosphorous content. In addition, increasing the application period of either the vermicompost or the vermiwash resulted in increased soil pH, electrical conductivity, phosphorous and potassium content but resulted in reduced phosphorous content. The reduction of the soil nitrogen content is attributed to de-nitrification, whilst the increase in phosphorous content is attributed to increase in soluble phosphates and release of nutrients into the soil due to microbial activity in the bio-fertilizers. Furthermore, loam-clay soils have good absorbing properties for potassium. The soil properties and micro-organisms present in the bio-fertilizers play a critical role on the modification of the soil physicochemical properties
Effective Separation of Vermicasts fromEarthworms Using a Cylindrical Rotary Trommel Separator
(International Journal of Innovative Research in Science, Engineering and Technology, 2013-08-02) Manyuchi, Musaida Mercy; Phiri, Anthony
Vermicomposting technology is widely being used worldwide as a solid waste management strategy. During vermicomposting Eisenia fetida earthworms ingest the solid organic waste and after a bioconversion process it is expelled as vermicasts. These vermicasts can be used as solid bio-fertilizers; however there are challenges of separating the earthworms from the vermicasts after vermicomposting. Pilot studies were therefore done using a cylindrical rotary trommel screen separator prototype to efficiently separate the earthworms from the vermicasts. The vermicasts were obtained from vermicomposting waste corn pulp mixed with cow dung manure and waste office paper. The cylindrical rotary screen had a mesh size of 4 mm, length of 250 mm and diameter of 90 mm. A throughput of 1.3 m3 /hr comprising of vermicasts and earthworms with a moisture content of 40-60% was separated trommel screen rotational speeds of 30-70rpm. The vermicasts separation efficient was around 80-95% but optimum separation of 95% was achieved at 40% moisture content and trommel screen rotational speed of 50rpm. Using a mechanical trommel screen separator increased the separation of vermicasts and earthworms, hence making the vermicomposting technology ideal.
Impact of Vermicompost on Lettuce Cultivated Soil
(International Journal of Inventive Engineering and Sciences (IJIES), 2013-10-02) Manyuchi, Musaida Mercy; Mudamburi, T; Phiri, Anthony; Muredzi, Perkins
— Vermicomposting is an environmentally friendly technique that is used for organic solid waste management. Waste corn pulp blended with cow dung and office paper was vermicomposted over 30 days to produce vermicompost which is a bio-fertilizer. The vermicompost was applied to soil cultivated with lettuce at the planting and after every four weeks. The impact of vermicompost on the soil was quantified. Application of vermicompost resulted in a 5%, 21.7%, 16.9% and 4.92% increase in soil pH, nitrogen, phosphorous and manganese content respectively. Application of the vermicompost also resulted in a 9.41% and 3.77% decrease in soil electrical conductivity and potassium content respectively. However, application of vermicompost did not alter the copper and zinc content of the lettuce cultivated soil. The lettuce showed vigor and vitality during the period of growth. Vermicompost can be used for sustainable agriculture practices
Integrated Municipal Solid Waste Management System (IMSWMS)
(2016 Mauritius International Conference on Biological, Chemical and Agricultural Sciences (BCAS-16), 2016-03-20) Nleya, Magripa; Gunda, Lovemore; Chisadza, Zvirevo; Manyuchi, Musaida Mercy
Rapid population growth, industrialization, urbanization and technology trends have led to a sharp increase in solid waste generation. Some municipalities are still using the conventional approach to solid waste management leading to solid waste becoming a sight everywhere. It is important to monitor solid waste collection and record the information pertaining to collection time, area and other related data from a central location. For this purpose, an Integrated Municipal Solid Waste Management System (IMSWMS) is presented and discussed in this paper. The system ensures solid waste reduction through proper collection monitoring, waste intelligence initiatives and environmental education. It is an embedded system incorporating global positioning system (GPS), radio frequency identification (RFID) technology, which is interfaced with a microcontroller and a web based graphical user interface (GUI) that can be accessed from anywhere. The web based GUI allows real time interaction of the central office with waste collection processes and residents
Pilot Scale Studies for Vermifiltration of 1000m3 /day of Sewage Wastewater
(Asian Journal of Engineering and Technology, 2013-03-01) Manyuchi, Musaida Mercy; Kadzungura, Luckmore; Boka, Sandra
Vermifiltration is a technology in which the combined action of earthworms’ activity and theabsorption properties of soil, sand and gravel particles on the organic pollutants are applied for wastewater treatment. Vermifiltration was used in sewage wastewater treatment as a cheaper and enviro-friendly technology. 1000m3 /day of sewage wastewater was treated in a four layered vermifilter at an Eisenia fetida earthworm density of 8 000 earthworms/m2 in a 3.6m2 soil bed. The vermifilter bed layers comprised of 4-8mm garden soil particles, 8-12mm mixed sand and gravel particles, 30-50mm small aggregates and 70-80mm large aggregates respectively. A vermifilter bed porosity of 0.96 was used. The vermifilter had a hydraulic retention time of 0.082days and a hydraulic loadingrate of 0.93m3/m2.day. The vermifilter design effectively resulted in over 90% reduction in BOD, COD, TDSS andturbidity as well as neutralized pH in the sewage wastewater. Proper vermifilter design ensures optimum sewage wastewater treatment for potential use in irrigation
TECHNO-ECONOMIC ANALYSIS FOR VIRGIN PAPER PRODUCTION FROM BAGASSE
(8 th Zimbabwe Institute of Engineers Congress, 2014-09-14) Manyuchi, Musaida Mercy; Chiwanga, Auxilliah. T.; Nkomoc, D. J.
The pulp and paper manufacturing industry relies heavily on importing waste paper as its raw material from neighbouring countries such as South Africa. At the same time, the available local resource is wood and cutting this results in environmental problems. As a measure to foster value addition and beneficiation as well as reduce deforestation, there is need to use alternative raw materials such as bagasse which is readily available at sugar plantations. This study involved the processing of 40 tons per day of virgin paper from bagasse as an alternative option using the Kraft process with a conversion yield of 35%. Optimum operating pressure and temperature were found to be 9.6 atmospheres and 200oC respectively and a detailed process design was done considering the process safety issues. After an environmental impact assessment the bagasse to virgin paper plant was recommended for siting in Chiredzi. An economic analysis carried out indicated a return on investment of 45% and a payback period of 2.2 years. The net present value was found to be $757 792 with the virgin paper selling price set at $108/ton. Henceforth the project is both technically and economically feasible.
Treatment of Piggery Wastewater using an Acti-zyme (Biocatalyst) and Paper mill Biochar Compound Co-capturing Biogas
(5 th Anniversary of ANSOLE (2011-2016): International Conference on Renewable Energy (INCORE2016), 2016-02-03) Manyuchi, Musaida Mercy; Guvavaa, Grace N.; Ikhu-Omoregbe, Daniel I. O; Oyekola, Oluwaseun O.
The world is facing formidable challenges in meeting rising demands of clean water as the available supplies are depleting due to extended droughts, population growth, more stringent health based regulations and competing demands from a variety of users. At the same time, wastewater treatment plants are using energy from the national grid rather than generating their own energy. Piggery farms and paper mills make use of a lot of water and thus contribute towards water shortage. The piggery farms produce a significant amount of wastewater which water can be effectively treated via anaerobic routes to harness biogas. On the other hand, paper mills are generate excessive amounts of sludge during paper making process. Secondary treatment of wastewater can therefore be used to make sludge based activated biochar which can be used in wastewater treatment. This work assessed the feasibility of using a compound from activated carbon from paper mill sludge (PMS) and Acti-zyme (a digestion bio-catalyst) to treat piggery wastewater anaerobically and co-capturing the biogas produced for energy usage. A piggery wastewater treatment plant generating 6000 m3 /day of wastewater was considered and the change in the wastewater physicochemical properties was determined using standard methods. The amount of biogas produced was determined using a water displacement method for retention periods of 30 days at 37 °C. The use of Acti-zyme and PMS biochar compound at 50 g/m3 reduced the piggery wastewater contaminants properties such as total solids, colour, pH and BOD5 by >70%. The treated effluent met the set standards for effluent water disposal. Biogas was produced at a rate of 2.3 m3 /m3 .day with a bio-methane composition of about 78%
Vermicomposting in Solid Waste Management: A Review
(International Journal of Scientific Engineering and Technology, 2013-12-01) Manyuchi, Musaida Mercy; Phiri, Anthony
Vermicomposting is a bio-conversion process which is widely being used for solid waste management. In this bio-conversion process, earthworms feed on the organic waste to produce more earthworms, vermicompost and vermiwash as products. Earthworms which include Megascolex Mauritii, Eisenia Fetida, Eudrilus Eugeniae, Perionnyx Excavatus, Lampito Mauritii, Eisenia Andrei, Lampito Rubellus and Drawida Willis have been widely used for vermicomposting. Vermicomposting has been done for various wastes including animal, plant, pharmaceutical, food waste and sewage waste over vermicomposting periods ranging from 28-120 days using these earthworms. The process conditions during vermicomposting ranged from 18- 67°C for temperature, pH 5.9-8.3 and moisture content 10.6-80%. Vermicompost yields of 30-50% have been achieved for various organic wastes and composting periods. The vermicompost and vermiwash produced were rich in nitrogen,phosphorous and potassium (NPK). The vermicompost obtained had NPK compositions ranging from 0.3-4.19%, 0.2- 1.6% and 0.2-6.18% respectively. The vermiwash obtained had NPK composition ranging from 0.14-1.58%, 0.05-7.53% and 0.47-1.26% respectively. Vermicompost and vermiwash have been applied on cow pea, soy bean, maize and marigold as bio-fertilizers. Vermicomposting can be used for solid waste management and the production of bio-fertilizers
Vermifiltration of Sewage Wastewater for Potential Use in Irrigation Purposes Using Eisenia fetida Earthworms
(World Academy of Science, Engineering and Technology, 2013-02-05) Manyuchi, Musaida Mercy; Boka, Simbarashe; Kadzungura, Luckmore
—Vermifiltration was used for treatment of sewage wastewater using the Eisenia fetida earthworm species. The earthworms’ gut acted as a bioreactor and they reduced the sewage wastewater solid and liquid organic wastes through ingestion and expelling these as vermicompost. 500 earthworms were used in the vermifilter over a 5 period of days. The treated water pH increased from being acidic to neutral. The sewage wastewater biological oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved and soluble solids (TDSS) and turbidity decreased by 98%, 70%, 95% and 98% respectively through vermifiltration. Vermifiltration significantly decreased the sewage water physicochemical parameters compared to an ordinary bio-filter without earthworms. The vermi-treated sewage water compared well with the set standards for irrigation water. Vermifiltration technology can therefore be applied as an environmentally friendly technique for sewage water treatment for irrigation purposes
Women in Engineering for Economy Recovery in Zimbabwe
(Asian Journal of Business and Management, 2013-08-03) Manyuchi, Musaida Mercy
Engineering is the application of scientific and mathematical knowledge as well as creativity for the development of solutions as well as for technology advancement. Previously the engineering field has been male dominated but of late women are taking up this discipline although the rate is still as low as 25%. The low uptake of these engineering fields by women therefore affects the output of women engineers into the society and consequently therefore failure to meet the engineering demands of our country. However, due to the women friendly policy implementation in Zimbabwe, involvement by women in engineering is increasing. Women engineers are helping ease problems of special skills shortage as well as lowering the gender imbalance that has existed in this field. Furthermore, participation by women engineers minimizes the employment shortage as well as re-boosting the economy in all fields such as academia, industry and entrepreneurship. Women engineers on the ground are working hard participating in the economic recovery of Zimbabwe but, there is need for more for an effective change. This is achievable through awareness campaigns and implementation of policies crafted to empower women.