Browsing by Author "Manyuchi, M.M"

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ACTI-ZYME BIOCHEMICAL PROPERTIES: POTENTIAL FOR USE IN ANAEROBIC SEWAGE TREATMENT CO-GENERATING BIOGAS
(Asian Journal of Science and Technology, 2015-03) Manyuchi, M.M; Ikhu-Omoregbe, D. I. O; Oyekola, O. O.
The biochemical properties for Acti-zyme, a biocatalyst were characterized for potential use in anaerobic sewage treatment with the aim of producing biogas. Sterile Acti-zyme media containing peptone water was plated on the MacConkey Agar, Starch Agar, Kliger Agar, Urease Agar, Sulphide Indole and Motility Agar at 37.5°C for 24 hours, at a pH of 7±0.2. Acti-zyme was found to be immotile and contained several enzymes that have different applications in sewage treatment. These included catalase which detoxified harmful substances, protease which broke down the proteins as well as amylase which broke down the polysaccharides available in sewage. However, Acti-zyme did not contain urease; an ammonium catalyzing enzyme. Acti-zyme did not to promote H2S production which is a contaminant in biogas production. Acti-zyme also did not contain pathogenic Enterobacteriaceae such as E. Coli and Salmonella. The identified Acti-zyme biochemical properties make it useful in sewage treatment co-producing biogas
Bioremediation of Transport Industry Contaminants Using Vermicompost
(International Journal of Environmental Engineering Science and Technology Research, 2014-01-01) Manyuchi, M.M; Phiri, A
Transport industries pose environmental challenges due to leaks of engine oils both to soil and water. Engine oil is highly organic therefore there is need to bio-remediate the contaminated soil and wastewater in order to preserve the environment. Soil and wastewater contaminated with diesel engine oil were bio-remediated using vermicompost containing live Eisenia Fetida earthworms and cocoons over a 4 week period. The contaminated soil and water pH and electrical conductivity (EC) were monitored during this period. Furthermore, the wastewater dissolved oxygen (DO) and biological oxygen demand (BOD) were determined. The pH in the contaminated soil decreased from 7.2 to 6.2 whilst that in the contaminated wastewater increased from 5.8 to 7.2. The EC in both the diesel contaminated soil and wastewater showed a decrease of more than 19%. The DO in the wastewater showed a decrease upon addition of vermicompost and then later on increased. Lastly, the BOD in the wastewater, decreased by 16.9% upon addition of the vermicompost. Vermicompost can be used for the vermiremediation of soil and wastewater contaminated with engine oil in the transport industries.
Comparison of Vermicompost and Vermiwash Bio-fertilizers from Vermicomposting Waste Corn Pulp
(World Academy of Science, Engineering and Technology, 2013-07-07) Phiri, A; Muredzi, P; Manyuchi, M.M; Chitambwe, T
—Vermicomposting is the conversion of organic waste into bio-fertilizers through the action of earthworm. This technology is widely used for organic solid waste management. Waste corn pulp blended with cow dung manure was vermicomposted over 30 days using Eisenia fetida earthworms species. pH, temperature, moisture content, and electrical conductivity were daily monitored. The feedstock, vermicompost and vermiwash were analyzed for nutrient composition. The average temperature and moisture content in the vermi-reactor was 22.5◦C and 42.5% respectively. The vermicompost and vermiwash had an almost neutral pH whilst the electrical conductivity was 21% higher in the vermicompost. The nitrogen and potassium content was 57% and 79.6% richer in the vermicompost respectively compared to the vermiwash. However, the vermiwash was 84% richer in phosphorous as compared to vermicompost. Furthermore, the vermiwash was 89.1% and 97.6% richer in Ca and Mg respectively and was 97.8% richer in Na salts compared to the vermicompost. The vermiwash also indicated a significantly higher amount of micronutrients. Both bio-fertilizers were rich in nutrients specification for fertilizers.
Design of a pyrolysis reactor for biochar production for ‘motocharcoal’ briquettes
(5 th Anniversary of ANSOLE (2011-2016): International Conference on Renewable Energy, 2016-02-03) Kanyenga, P.; Manyuchi, M.M
Zimbabwe is an agro-based country and as a result produces a lot of agro-waste ca. 70 000 tons per year. This waste occurs primarily in the form of waste cornstover, bagasse and sawdust which are currently not being utilized. There is potential for conversion of this agriculture waste to charcoal briquettes using the slow pyrolysis technology which increases the waste materials’ heating value. This paper presents a design for a pyrolysis reactor that can be used for conversion of agricultural waste to biochar which can then be used to make, Motocharcoal which is a trade name for the densified charcoal briquettes that are currently being made in Zimbabwe. It is an eco-fuel that can be used for heating and cooking purposes with a heating value of 22.5 MJ/kg. The pyrolysis reactor design was carried out based on an operating capacity of 12 tons/hr for an 8 hour working period based on the availability of the raw material which was mainly cornstover with a density of 200 kg/m3 . Pyrolysis took place under anaerobic conditions to enhance carbonisation. This was done at a temperature of 300 °C and a retention time of 3 hours to increase the calorific value of the biochar before briquetting. A conversion rate of 70% from agro-waste to biochar was achieved. The pyrolysis reactor will be constructed using stainless steel. Temperature and pressure were identified as the critical process parameters that must be controlled as these affect the quality of the biochar which in turn affects the briquettes quality. The pyrolysis reactor volume was 15.3 m3 with atmospheric pressure as the working pressure and a design pressure of 14.9 MPa. Fiberglass will be used as the insulation material to minimise heat losses and water used as the cooling agent. The designed pyrolysis reactor will ensure optimal conversion of the agro-waste to biochar for high quality briquettes
Distillery Effluent Treatment Using Membrane Bioreactor Technology Utilising Pseudomonas Fluorescens
(International Journal of Scientific Engineering and Technology, 2013-12-01) Manyuchi, M.M; Ketiwa, E
Distilleries produce vast amounts of contaminated effluents which if disposed to the water bodies will pose environmental problems hence need to treat this effluent. A membrane bioreactor with Pseudomonas fluorescens as a decolorizing micro-organism was employed for treatment of distillery effluent over 10 days. The effluent pH changed from being acidic (4.2-5.0) to neutral (7.3-8.0). The effluent BOD, COD, TDS and TSS was significantly reduced by more than 90%. The membrane bioreactor sufficiently improved the effluent water quality parameters due to the degradation of the organics and removal of the suspended matter through microfiltration. Membrane bioreactor technology can be used for treatment of distillery effluents.
Effect of Drying on Vermicompost Macronutrient Composition
(International Journal of Inventive Engineering and Sciences (IJIES), 2013-09-05) Manyuchi, M.M; Phiri, A; Muredzi, Perkins; Chirinda, N
Vermicomposting is widely being used for bio-conversion of organic wastes into bio-fertilizers. Vermicompost which was obtained from various food wastes was dried at 105◦C for 5 minutes in a moisture analyzer. The dried vermicompost macronutrient composition was analyzed and quantified over the raw vermicompost. The dried vermicompost total nitrogen content was 31.25% lower as compared to the raw vermicompost whereas , the phosphorous and potassium content were 63.75% and 72.86% higher in the dried vermicompost compared to the raw vermicompost respectively. Vermicompost can be dried for easier packaging, storage and transportation as the drying process in overall enhances nutritional value to the vermicompost
GRANULATION OF VERMICOMPOST USING VERMIWASH AS BINDING MEDIA
(Global Journal Of Engineering Science And Researches, 2014-03-01) Manyuchi, M.M; Nyamunokora, M
Vermicompost is a bio-fertiliser that is obtained from the bio-conversion of organic waste using earthworms. However, this vermicompost exist in paste form thereby the need for granulation to make it easier to store and transport. Vermicompost was granulated using vermiwash as the binding agent. Vermiwash was chosen as an alternative over water due to the presence of fertiliser macro and micro nutrients in the vermiwash. The vermicompost nutritional composition was tested before and after granulation. The granulated vermicompost indicated a 48.9%, 55.4%, 75% increase in nitrogen (N), phosphorous (P) and potassium (K) content upon granulating using vermiwash. The vermicompost ash content increased by 71.2% upon granulation whilst the moisture content decreased by 84%. Granulation of vermicompost using vermiwash enhances the vermicompost NPK composition at the same time making large scale production easier.
TECHNO FEASIBILITY FOR REFINING OF USED LUBRICATING OILS AS A VALUE ADDITION STRATEGY
(Royal Academy of Engineering Conference-Enriching Engineering Education in AfricaVictoria Falls, Zimbabwe, 2015-07-23) Nengiwa, T. O.; Manyuchi, M.M
Refining is a process of refurbishing used oil to high-quality base oil by removing contaminants, water and spent additives. The study involves refining of 1tonne per day used lubricating oil to produce 0.75 tonnes per day refined oil with 80% plant utilization. The process involved dehydration, solvent extraction, hydro-treating and agitated thin film evaporation. Process conditions were experimentally determined. Optimum conditions of 4:1 solvent ratio and 4 mBar evaporation pressure produced refined oil of 24% ash content, 98cP viscosity, -11oC pour point, 180oC flash point and specific gravity 0.909. Detailed major equipment design of an agitated thin film evaporator, its process control and HAZOP was done.
Techno-economic assessment for biochar production from paper mill sludge
(Research and Intellectual Outputs 2016-Science, Engineering and Technology,, 2016-09-04) Manyuchi, M.M; Chaukura, N; Ruzvidzo, C
Sludge generated from the wastewater treatment plant of a pulp and paper factory was used as feedstock for the preparation of biochar using fast pyrolysis followed by chemical activation with NaOH to make activated biochar (ABC). A process utilising 300 kg/day of waste paper mill sludge (PMS) was designed with a plant utilisation of 80%. A pyrolysis temperature of 500 oC and residence time of 2 h was used in a limited oxygen pyrolysis reactor producing biochar at a yield of 40 %. The biochar was activated using NaOH and heated for an hour at 70 oC to enhance the sorption properties of the ABC. The resulting ABC had a BET surface area of 492.02 m 2 /g, had decolourising properties and a pH of 7, hence applicable in wastewater treatment. A capital investment of US$1 860 729.47 is required and the plant life is 20 years, with a net present value of US$ 1 832 445.94. The rate of return is 29.6 %, return on investment is 26.9% and a payback period of 3.7 years. The production of ABC from PMS is economically feasible, with a product selling price of $30.00/kg.
TECHNO-ECONOMIC ASSESSMENT FOR BIOGAS GENERATION FOR ENERGY USAGE FROM MUNICIPAL SEWAGE SLUDGE USING ACTI-ZYME AS DIGESTION CATALYST
(Chemical Science International, 2016-01-21) Manyuchi, M.M; Ikhu-Omoregbe, D.I.O; Oyekola, O. O.; Gwarimbo, W
A sewage plant with a capacity of 19 600 m3 /day was considered for techno-economic assessment, with an operating efficiency of 60% and a life span of 20 years. $5.125/day of Acti-zyme 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. Capital budgeting techniques were then used for techno-economic assessment of sewage treatment recovering biogas and bio-solids. 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 $1 186 239.23 was realized with an internal rate of return of 17.6% and a payback period of 5.9 years. For breakeven to be realised, only 183 059.16 KWh must be produced. The techno-economic assessment indicated it is viable to treat sewage using Acti-zyme co-harnessing biogas and bio-solids as valued added products to an extent of making 0.04% to the Zimbabwe gross domestic product.
Techno-economic feasibility of using sorghum brewers spent grain to generate one megawatt of electricity using direct combustion technology
(Conference: 47th Ghana Institution of Engineers (GhIE) Annual Conference,, 2016-03-29) Manyuchi, M.M; Frank, R
The paper presents a study that was conducted to assess the techno-economic feasibility of a sorghum brewers spent grain (BSG) fired boiler unit to generate 1 megawatt of electricity for a certain brewery company. The brewery company is currently generating 24 tons per day of sorghum brewers spent grain biomass waste which was used as a source of boiler fuel for this work. After a full proximate analysis the sorghum brewers spent grain had an average heating value of 12.6 MJ/kg whilst coal had 19.9 MJ/kg indicating that it is feasible to generate electricity using sorghum brewers spent grain as a source of fuel, and that sorghum brewers spent grains can be used as an alternative to coal. A process for conversion of the BSG to electricity was proposed for a biomass boiler unit consuming 1100 kg/hr BSG, operating at 86% efficiency, maximum pressure of 9 bar and steam output of 1689kg/hr was designed to supply a one megawatt turbine generator. Pressure, temperature and flow control mechanisms were assessed as a safety consideration. An economic analysis was done with a total investment cost of USD$ 3.4 million, a payback period of 3.7 years, and a return on investment of 27.4%. BSG provide an alternative source of electricity for the brewery industry
TECHNO-FEASIBILITY OF A PLANT TO CAPTURE 8TPD OF METHANE GAS FROM SEWAGE SLUDGE
(Royal Academy of Engineering Conference-Enriching Engineering Education in Africa, 2015-07-23) Manyuchi, M.M; Patsanza, T
Currently, there is an increase in amounts of sewage sludge and disposal routes are limited posing a great threat to the environment, at the same time, economic hardships in production of electricity have also led to constant load shedding and higher electricity rates nationwide. This study was conducted to develop a plant to capture methane gas from sewage sludge for electricity generation with minimized human intervention so as to cab the above stated effects.72% of methane gas was captured from sewage sludge over a 15 day period. Mass and energy balances for the methane capturing plant showed that a throughput of approximately 617 kg/hr sewage sludge would give the stated amount of methane. This amount of methane gas when converted to electrical energy would also sustain Harare`s daily electrical consumption of 1600MW. Process conditions were observed to be at mesophillic temperature of 37ᴼC- 40ᴼC.The bio digester as the major piece of equipment was designed with an installed carrying capacity of 10 tons of sewage sludge. Based on design calculation, the digester was predicted to produce up to 8 tons per day of methane and 1125 kg of organic fertilizer from the digestate. An economic analysis was also carried out and the process proved to be viable economically as it has a payback period of 3 years for a unit cost of $2.50 /kg and is most likely not to face bankruptcy as shown by low capital gear ratio. This project proved to be technically and economically viable as it also supports the Zim Asset in providing a benefit to the nation