alkaline digester Articles

  • Improved methane production from waste activated sludge with low organic content by alkaline pretreatment at pH 10

    Sludge with low organic content always results in an unsatisfactory performance, even failure of anaerobic digestion. The alkaline pretreatment effect on anaerobic digestion of sludge with low organic content has seldom been studied although it gives many benefits for sludge with high organic content. In this study the influence of alkaline pretreatment (pH 10, an effective alkaline pH) on the ...


    By IWA Publishing

  • The use of microalgae and their culture medium for biogas production in an integrated cycle

    Vinasse is a residue produced in large quantities as a sub-product of ethanol production. Anaerobic digestion of vinasse can yield large amounts of biogas, but often difficulties arise in maintaining stable operation, due to the acidity of the material (which has a pH between 3.5 and 5) and a strong tendency to further acidification. Anaerobically digested vinasse can be used as part of a ...


    By IWA Publishing

  • Effect of thermal alkaline pretreatment on the anaerobic digestion of wasted activated sludge

    The effect of alkaline pretreatment of waste-activated sludge, using two models to study the sequential hydrolysis rates of suspended (Sanders' surface model) and dissolved (Goel's saturation model) solids, on the mesophilic and thermophilic anaerobic digestion rate is evaluated. The pretreatment, which reduces the size of the solids, increases the reaction rate by increasing the surface area and ...


    By IWA Publishing

  • Evaluation of alkalinity spatial distribution in an up-flow fixed bed anaerobic digester

    In this paper, an experimental study upon alkalinity and hydrodynamic behavior in an anaerobic up-flow fixed bed reactor for the treatment of tequila vinasses is presented. Measurements of volatile fatty acids, pH, alkalinity and bicarbonate were obtained at three sampling points in the reactor in the axial axis. Then, the spatial distribution of alkalinity is studied and discussed. Moreover, ...


    By IWA Publishing

  • Anaerobic treatment of food waste in pilot scale

    For this work, a pilot scale anaerobic digester was used to assess the treatability of food waste from a canteen. The digester was operated for 720 days, and its efficiency in removing organic matter and suspended solids as well as producing biogas were assessed. At the beginning of operation, the digester failed and alkalinity buffering was required until stabilization. A maximum chemical ...


    By IWA Publishing

  • Parallel evaporation after extraction of liquid dairy samples following the Mojonnier method (ISO 1211:2010) – gravimetric fat determination

    Parallel evaporation after extraction of milk samples with the Mojonnier The fat in liquid dairy samples is usually extracted with an organic solvent that is then evaporated to complete dryness prior to gravimetric analysis. In this short note, initial conditions and evaporation settings for the parallel evporation of milk fat dissolved in diethyl ether / light petroleum are presented. ...


    By BÜCHI Labortechnik AG

  • Towards a sustainable use of food waste: influence of urea on biogas production potentials of selected fruit wastes in Addis Ababa, Ethiopia

    This study evaluates the influence of adding urea on biogas (methane) production potentials of selected fruit wastes. Using standard methodology, the finding revealed that all the fruit wastes are ideal substrates for biogas production. The ultimate biogas yield on anaerobic digestion of fruit waste feeds, avocado, banana, and mango, are 0.48, 0.57, 0.53 l/g VS without urea supplement and 0.76, ...


    By Inderscience Publishers

  • Sewage sludge pretreatment by microwave irradiation combined with activated carbon fibre at alkaline pH for anaerobic digestion

    This research focuses on the effects of microwave-assisted activated carbon fibre (ACF) (MW-ACF) treatment on sewage sludge at alkaline pH. The disintegration and biodegradability of sewage sludge were studied. It was found that the MW-ACF process at alkaline pH provided a rapid and efficient process to disrupt the microbial cells in the sludge. The results suggested that when irradiated at ...


    By IWA Publishing

  • Use of waste whey in tanning industry

    The name of the deliming process suggests that the aim of the process is to remove the lime from the white hide. However, this is not complex enough. The primary purpose of the deliming procedure is to prepare the hide for bating and pickling. In order to do that, it is necessary to reach a suitable pH level to permit the bating enzymes to be active, and partially remove the excess lime. It is ...


    By ORBIT e.V.

  • High dry solids digestion

    ABSTRACTDigestion of sewage sludge normally takes place at pH values between 7,0 and 7,5. Control methods of the process stability are based on practical experience such as the ratio of volatile fatty acids (VFA) and total alkalinity (TA). Thermal sludge disintegration for an enhanced digestion process allows a digester feed with higher dry solids concentrations. This is due to an opening of ...


    By Cambi Group AS

  • High dry solids digestion

    Abstract Digestion of sewage sludge normally takes place at pH values between 7,0 and 7,5. Control methods of the process stability are based on practical experience such as the ratio of volatile fatty acids (VFA) and total alkalinity (TA). Thermal sludge disintegration for an enhanced digestion process allows a digester feed with higher dry solids concentrations. This is due to an ...


    By Cambi Group AS

  • Factors Affecting Disinfection and Stabilization of Sewage Sludge

    ABSTRACTEffective disinfection and stabilization of sewage sludge prior to land application is essential to not only protect human health, but also to convince the public of its benefits and safety. A basic understanding of the key factors involved in producing a stable biosolid product is a necessary component to ensuring that effective disinfection and stabilization are achieved. Key stressors ...

  • Thermal hydrolysis pre-treatment for high solids anaerobic digestion

    The City and County of San Francisco completed a two-year pilot study of pre-treatment processes to mesophilic anaerobic digestion for improved biosolids stabilization and production of biosolids suitable for unrestricted reuse (class A biosolids). The results of this effort will help in the design of the new Solids Handling Facility (SHF) at the 11 m3/s Southeast Water Pollution Control Plant ...


    By Cambi Group AS

  • Enhancement of waste activated sludge anaerobic digestion by a novel chemical free acid/alkaline pretreatment using electrolysis

    Anaerobic digestion of waste activated sludge (WAS) is relatively poor due to hydrolysis limitations. Acid and alkaline pretreatments are effective in enhancing hydrolysis leading to higher methane yields. However, chemical costs often prohibit full-scale application. In this study, 12 V two-chamber electrolysis using an anion exchange membrane alters sludge pH without chemical dosing. pH ...


    By IWA Publishing

  • Alkaline treatment of high-solids sludge and its application to anaerobic digestion

    High-solids anaerobic digestion is a promising new process for sludge reduction and bioenergy recovery, requiring smaller digestion tanks and less energy for heating, but a longer digestion time, than traditional low-solids anaerobic digestion. To accelerate this process, alkaline sludge disintegration was tested as a pretreatment method for anaerobic digestion of high-solids sludge. The results ...


    By IWA Publishing

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