sewage sludge digester Articles

  • The impact of advanced digestion on incineration of sewage sludge

    Abstract Traditionally, when incineratin sewage sludge, it was preferable to burn raw undlgested sludge, as digestion - by extracting some of the energy from sludge- subsequently reduce its calorific value. However, when considering incineration as part of a wider strategy, the desicion whether or not to include digestion becomes less clear. Since, virtually all of the requirements of ...


    By Cambi AS

  • Pretreatment followed by anaerobic digestion of secondary sludge for reduction of sewage sludge volume

    The influence of two pretreatment methods, thermal treatment and low-pressure wet oxidation, on the sludge digestion efficiency was examined. Batch thermophilic anaerobic digestion was used to evaluate the effectiveness of the pretreatment methods in terms of volatile suspended solids (VSS) digestion efficiency and gas production. The results showed that the gas production was not proportional ...


    By IWA Publishing

  • Anaerobic thermophilic digestion of sewage sludge with a thickened sludge recycle

    The process of anaerobic thermophilic digestion of municipal wastewater sludge with a recycled part of thickened digested sludge, was studied in semi-continuous laboratory digesters. This modified recycling process resulted in increased solids retention time (SRT) with the same hydraulic retention time (HRT) as compared with traditional digestion without recycling. Increased SRT without ...


    By IWA Publishing

  • The influence of temperature and SRT on high-solid digestion of municipal sewage sludge

    The influence of temperature and solids retention time (SRT) on high-solid digestion of municipal sewage sludge was investigated in laboratory-scale reactors. Digestion with high-solid concentration reduces the required digestion volume and is advantageous for urban areas. The experimental conditions comprised total suspended solids (TSS) in digested sludge between 4.0 and 4.6%, temperatures ...


    By IWA Publishing

  • Two-phase anaerobic co-digestion of food waste and sewage sludge

    The feasibility and performance of food waste and sewage sludge co-digestion were investigated to gain insight into their resource utilization. In this study, two-phase anaerobic digestion (TPAD) was operated under a total solids mixing ratio of 1:1 and different sludge retention times (SRTs). Results show that an acidogenic reactor with a 5-day SRT obtained the highest acidification efficiency, ...


    By IWA Publishing

  • Effect of the addition of rice straw on microbial community in a sewage sludge digester

    Rice straw was added to a sewage sludge digester and its effects on methane production, dewatering characteristics, and microbial communities in the digested sludge were examined by a continuous digestion experiment under mesophilic conditions (35 °C). Stable gas generation was monitored in all digestion experiments. Methane yield from raw sludge, chopped rice straw and softened rice ...


    By IWA Publishing

  • Application of dried anaerobic digested sewage sludge as phenol biosorbent

    Untreated anaerobically digested sewage sludge was used for the first time as a biosorbent for removing phenol from aqueous solution. Results showed that adsorption capacity was influenced by the pH of the aqueous solution with an observed maximum phenol removal at pH around 6–8. The adsorption equilibrium of phenolic compounds was obtained after almost two hours with an adsorption of ...


    By Inderscience Publishers

  • Observing the effects of digestion and chemical dosing on the calorific value of sewage sludge

    New legislation being introduced in Europe for the removal of the macronutrients nitrogen and phosphorous is causing the fundamental composition of sludge to change. Nitrogen removal requires longer residence times during activated treatment, and phosphorous removal can involve the supplementation of chemicals such as ferric. In addition, there is increasing pressure to capture energy from sludge ...


    By United Utilities

  • Co-digestion of glycerine and sewage sludge to optimise green electricity production

    Sewage sludge and crude glycerine were co-digested in the mesophilic digester of Hoogstraten wastewater treatment plant. Additions of up to 1 kg of crude glycerine/(m³ reactor).(day) were done without significant operational problems. At higher dosage, severe digester foaming was observed. Methane production during co-digestion was up to 20% higher than what would be expected based ...


    By IWA Publishing

  • Thermophilic anaerobic digestion of sewage sludge with high solids content

    The treatment performance of thermophilic anaerobic digestion (AD) of sewage sludge with high solids content was investigated with two laboratory-scale thermophilic anaerobic reactors (R1 and R2) with a feeding of pre-centrifuged sewage sludge. Reactor R1 was fed with sludge of 3.7% total solids (TS). The volatile solids (VS) removal ratio and methane yield in the stable state were ...


    By IWA Publishing

  • New processes for the improvement of sludge digestion and sludge dewatering

    INTRODUCTIONThe examination of numerous sewage sludges from municipal wastewater treatment plants leads to the conclusion that on the one hand dewaterability of these sludges worsens and that on the other hand dewaterability of sludges becomes more and more important due to increasing disposal costs. Especially wastewater treatment plants with inflows from the food processing industry often face ...


    By Cambi AS

  • Co-fermentation of sewage sludge and biowastes

    The anaerobic treatment of sewage sludge has a long history in Germany. It began early in the Twentieth Century with the development of the Imhoff tank and has, since then, been con-tinuously further developed. Today, anaerobic sludge digestion is the most widely used process for stabilizing sewage sludges. Digesters, in which a portion of the sewage sludge is converted into utilizable biogas ...


    By ORBIT e.V.

  • Recovery of Phosphorus from Sewage Sludge

    In the following, a method to recover phosphorus from sewage sludge as MAP (magnesiumammonium- phosphate, also called struvite) is to be presented. The process uses sulfuric acid to leach phosphorus out of digested sewage sludge. After solid-/liquid-separation, interfering metal ions in the liquid phase are inactivated through complexation. For the subsequent precipitation of the phosphorus, ...

  • Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale municipal WWTP in Santiago de Chile, and fed with either primary or mixed sewage sludge. AD ...


    By IWA Publishing

  • Pollutants in Urban Wastewater and Sewage Sludge

    Untitled Document Executive Summary Water policy in the European Union is aiming to promote sustainable water use and a major ...

  • Toluene in sewage and sludge in wastewater treatment plants

    Toluene is a compound that often occurs in municipal wastewater ranging from detectable levels up to 237 μg/L. Before the year 2000, the presence of the aromatic hydrocarbons was assigned only to external sources. The Enhanced Biological Nutrients Removal Processes (EBNRP) work according to many different schemes and technologies. For high-efficiency biological denitrification and ...


    By IWA Publishing

  • Analysis of methane emissions from digested sludge

    The energetic use of sewage sludge is an important step in the generation of electricity and heat within a wastewater treatment plant (WWTP). For a holistic approach, methane emissions derived from anaerobic treatment have to be considered. Measurements show that methane dissolved in digested sludge can be analyzed via the vacuum salting out degassing method. At different WWTPs, dissolved ...


    By IWA Publishing

  • Transportation of digested sludges over extreme distances

    Sludge is a residual product of sewage treatment that, as a rule, is digested and concentrated. In larger processing plants, it is dehydrated, partially dried and subsequently utilised in other processes. This usually takes the form of incineration and subsequent use as an additive to building materials by the cement industry. In the sewage treatment plant (STP) of the local authorities ...


    By ALLWEILER GmbH

  • Use of an elemental balance over primary and secondary anaerobic digestion of sewage sludge to determine its carbon impact

    This paper details how a mass balance, which was conducted for all of United Utilities’ anaerobic digestion plants, was used to calculate emission factors for various types of anaerobic digestion processes to enable calculation their carbon footprint. The mass balance showed average volatile solids destruction rates of 45% and 11% over primary and secondary digestion respectively. The calculated ...


    By Cambi AS

  • Microwave and its combined processes: an effective way for enhancing anaerobic digestion and dewaterability of sewage sludge?

    The enhancement for sludge anaerobic digestion and dewaterability were investigated in sludge pretreated by microwave (MW) and its combined processes. The results showed that microwave and its combined processes can efficiently release soluble organic matter and thus enhance anaerobic digestion of sludge. The cumulative methane production in the test of the MW-H2O2-OH (0.2) process was ...


    By IWA Publishing

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