Methodology for advanced measurement accuracy of the overall volumetric oxygen transfer coefficient with application to hydrocarbon-aqueous dispersions

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Techno-economic assessment for producing 24 tpd of charcoal briquettes from corn stover as a value addition strategy

Currently developing countries are facing fuel challenges yet at the same time waste corn stover remains unutilized. This work was undertaken to utilize the excess corn stover for making bio-ethanol as a way of value addition by designing a plant manufacturing 150 tons per day of 99.5% pure cellulosic bio-ethanol operating over a 10 year period. The process which converted crude corn stover to cellulosic bio-ethanol was evaluated for conversion via hydrolysis lignocelluloses in the corn stover then the co-fermentation of the carbon 5 and carbon 6 monosaccharides obtained from hydrolysis process. The hydrolysis process is a route to the bio-ethanol through 86% co-fermentation of carbon 5 and carbon 6 sugars obtained from the 75% saccharification of corn stover to fermentable sugars to produce 99.5% pure cellulosic bio-ethanol that can be used to blend petrol. The economic analyses indicated a payback period of 1.5 years, a rate of return on investment of 86% and a selling price of $1.10/liter for the bio-ethanol indicating the feasibility of the project. Waste corn stover to bio-ethanol technology can be applied as a waste management tool to meet energy demands in agro based countries

Effect of Acti-zyme loading and retention time on sewage physicochemical properties during anaerobic treatment

Acti-zyme, an enzyme bio-catalyst was used for anaerobic sewage treatment. The sewage 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 (SO 42-), dissolved oxygen (DO) and the chemical oxygen demand (COD) were measured. All other parameters were measured by titrimetric methods; the pH and EC were measured by electrodes whereas the SO42- ions were measured by the gravimetric method. Effects of the Acti-zyme loading, retention time and their interaction on sewage physicochemical properties were determined using 22 factorial designs. Samples were incubated at 37°C under anaerobic conditions at agitation of 60 rpm. Acti-zyme loading was varied between 35-50 g/m3 whilst residence time was varied between 7-40 days. The sewage effluent TKN, BOD5, TSS, EC, CI-, TP, SO42-and COD decreased linearly >18% on increased Acti-zyme loading and residence time as well as their interactions unlike in Acti-zyme free effluent. The sewage pH changed from being alkaline to neutral and the DO increased by >200%. In overall, sewage treatment using Acti-zyme resulted in >90% decrease of the sewage contaminants. Highest sewage treatment conditions to meet the set guideline for disposal were obtained at 50 g/m3 Acti-zyme loading and retention time of 40 days

Innovative Biogas and Bio-solids generation from anaerobic sewage sludge digestion using acti-zyme as biocatalyst as a sustainable measure for developing countries

Sewage sludge was anaerobically digested using Acti-zyme, a biocatalyst for generation of biogas and bio-solids as an innovative strategy for obtaining biogas. Acti-zyme loadings of 35-50 g/m3 was employed for sewage sludge loading of 5-10 g/L. day in 250 mL reactors emanating the digesters. The agitation in the digesters was maintained at 60 rpm, at a mesophillic temperature of 37 °C for a period of 40 days. The biogas quantity produced was measured using the water displacement method daily. Samples of the biogas were collected and analyzed for bio-methane (CH4 ), carbon dioxide (CO2 ) and traces gases composition using gas chromatography. The bio-solids obtained were dewatered for destruction of pathogens and tested for nitrogen, phosphorous and potassium (NPK) content using uv-vis spectrophotometry. Optimum biogas quantity was produced at a sewage sludge loading of 7.5 g/L. day and Acti-zyme loading of 50 g/m3 with 78% CH4 unlike in Acti-zyme free digesters were a maximum of 65% CH4 was obtained. High nitrogen content bio-solids with 8.17 %, 5.84 % and 1.34 % of NPK respectively were produced. Acti-zyme is therefore an attractive bio-catalyst for sustainable sewage treatment for co-generation of biogas and bio-solids

Acti-zyme (bio-catalyst) as a solution for enhanced municipal sewage and sewage sludge treatment: effect of mesophillic and thermophillic digestion

The purposes of this paper is to compare the effect of mesophillic and thermophilic digestion of municipal sewage sludge utilizing Acti-zyme as the bio-catalyst as a value addition strategy to sewage sludge management. The municipal sewage sludge was digested to biogas and bio-solids (digestate). Experimental Design/Methodology/Approach: Raw sewage physicochemical properties were first characterized. Biogas and bio-solids was produced for anaerobic mesophillic conditions (37 o C) and thermophilic conditions (55 o C) for a retention period of 40 days in the bio-digester, Acti-zyme loadings of 0-70 g/m 3 and sewage sludge loadings of 5-10 g/L.day. Biogas composition was determined by a GC 5400 gas chromatography analysis whilst the The cumulative bio-solids (digestate) generated per day were recorded for possible use as biofertilisers. The nitrogen, phosphorous, and trace elements content was determined using Labtronics double beam ultra violet visible spectrophotometer (uv-vis). The potassium content was determined using a Thermo Fisher flame atomization absorption spectrophotometer. The effect of the digestion conditions were statistically quantified using a t-test. Findings: The biogas had a bio-methane (CH 4) composition of 72-78%, carbon dioxide (CO 2) composition of 16-20% and trace gases composition of 8-12%, whereas the bio-solids had a nitrogen, phosphorous and potassium composition of 8.17%, 5.84% and 1.32%. In overall biogas yield was more than 45% for all the sewage sludge loadings and Acti-zyme loadings digested at mesophillic conditions as compared to digestion at thermophilic conditions. This indicated that thermophilic catalyzed of municipal sewage sludge with Acti-zyme is not feasible as this result in less activity of the Acti-zyme hence less digestion occurs. In addition, the amount of bio-solids is about 40% higher in thermophilic digestion which can also result in landfilling problem. Research Practical implications and value: Mesophillic digestion of municipal sludge catalyst by Acti-zyme can be utilized for sewage sludge management as a value addition strategy. This can be applied for minimizing landfill problems resulting from sewage sludge from sewage treatment.Harare Institute of Technology and Cape Peninsula University of Technolog

Feasibility of using Acti-zyme in anaerobic biological sewage treatment

Acti-zyme, a biocatalyst has been used for vast applications such as wastewater treatment, drains cleaning and odor elimination for the past 50 years [1]. Acti-zyme has been reported to treat wastewater either aerobically or aerobically, reducing wastewater contaminants properties such as total nitrogen (TKN), total phosphates (TP), nitrates, ammonia, biochemical oxygen demand (BOD) and total suspended solids (TSS) by >40%. Acti-zyme also increases dissolved oxygen (DO) by >100% in treated wastewater promoting aquatic life [1]. The use of Acti-zyme like any biological catalyst under anaerobic conditions has the potential to favor biogas production [2]. On the other hand sewage, a form of wastewater is being generated every day resulting in huge quantities of sewage sludge. There is need for sustainable and economical ways of treating this sewage; harnessing biogas being one of them [3]. Biogas is mainly composed of methane and can be used to meet electricity demands as well as other energy requirements of the sewage plants [4]. Acti-zyme therefore poses an economic and environmentally friendly way of treating sewage utilizing its biochemical properties [1]. This study focused on biochemical analysis of Acti-zyme so that its use in sewage treatment as a biological technique can be validated. Furthermore, application of Acti-zyme in sewage treatment, sludge digestion, biogas and biosolids production were investigated.Harare Institute of Technology and Cape Peninsula University of Technolog

Acti-zyme biochemical properties: potential for use in anaerobic sewage treatment Co-Generating Biogas

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.Harare Institute of Technolog

Treatment of piggery wastewater using an acti-zyme (Bio-catalyst) and papermill biochar compound co-capturing biogas

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%