scholarly journals Advanced process for thermal treatment of wastewater sludge

2007 ◽  
pp. 23-33
Author(s):  
Mika Horttanainen ◽  
Juha Kaikko ◽  
Riikka Bergman ◽  
Katja Kakko ◽  
Hanna-Mari Manninen ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Combustion Process ◽  
Treatment Plant ◽  
Industrial Process ◽  
District Heating ◽  
Wastewater Sludge ◽  
Sludge Treatment ◽  
Pre Treatment ◽  
Sludge Drying ◽  
Dried Sludge

In addition to composting and anaerobic digestion, thermal treatment is one of the mostimportant treatment methods of wastewater sludge. There are special sludge incinerationplants, built for large volumes of wastewater sludge. Sludge is also burned with other fuels,especially in the forest industry. Energy from the combustion process is usually utilized asheat only or in combined heat and power production. Combustion diminishes the volume ofthe sludge by 80 to 96% depending on the moisture and ash content of the sludge. The delaytime of the material in the combustion process is a few seconds as opposed to several days inbiological processes. At the same time, all the pathogens are completely destroyed. Thechallenges in combustion are often related to the high moisture content of the sludge, whichcan cause problems to the stability of the combustion. Sludge can be dried thermally beforecombustion to avoid these problems.In this study, we introduce the modeling results of a sludge treatment process based onthermal drying and combustion. The process utilizes the released energy in distributedelectricity production.The process under review burns the dried sludge and produces high-pressure steam in anormal power plant process. The steam is led to the turbine where heat is converted tomechanical energy. After the backpressure turbine, the steam still contains a lot of thermalenergy. In the case study this heat is not used for district heating or industrial process heatingpurposes but utilized totally for sludge drying. One advantage of this process is that no heatload is required at the sludge treatment plant, often situated far from district heating networksor industry. The need for mechanical drying of sludge can also be optimized to save in thecosts of the mechanical drying facilities and energy. With the example case it is shown howthe pre-treatment, thermal drying and combustion should be designed to achieve a purelyelectricity producing process which does not need any other sources or consumption ofenergy.

Destruction of Faecal Bacteria, Enteroviruses and OVA of Parasites in Wastewater Sludge by Aerobic Thermophilic and Anaerobic Mesophilic Digestion

1991 ◽  
Vol 24 (2) ◽  
pp. 377-380 ◽  
Author(s):  
E. G. Carrington ◽  
E. B. Pike ◽  
D. Auty ◽  
R. Morris
Keyword(s):  
Sewage Treatment ◽  
Treatment Plant ◽  
Wastewater Sludge ◽  
Sludge Treatment ◽  
Volatile Solids ◽  
Working Volume ◽  
Thermotolerant Coliforms ◽  
Mesophilic Digestion ◽  
Faecal Bacteria ◽  
Faecal Streptococci

A new sludge treatment plant at Harrogate South Sewage Treatment Works is designed to handle up to 4 tonnes (dry solids) daily. Sludge is thickened continuously up to 8% (ds) and is then treated in parallel anaerobic mesophilic (AD) and thermophilic aerobic digestion (TAD) plants each with a maximum working volume of 530m3. Microbiological studies were carried out to compare the destruction of pathogens and faecal indicator bacteria. The AD plant operated with a mean retention of 26 days at 34 °C and achieved 49% reduction of volatile solids. The TAD plant operated with a mean retention of 28 days at 55 °C and reduced volatile solids by 35%. Operation was on a pump in-pump out cycle, guaranteeing 4h retention for all sludge. The disinfecting ability of TAD exceeded that of AD since it reduced counts of Enterobacteriaceae, thermotolerant coliforms and faecal streptococci to below 103/100ml, rendered cytopathic enteroviruses undetectable and destroyed viability of Ascaris suum ova within 4h. The AD process reduced bacterial counts by 90% and enteroviruses by 99%, but has no effect upon viability of Ascaris ova.

scholarly journals Relationship between centrifugation and drying of sludge and the organic halogens

2010 ◽  
Vol 58 (5) ◽  
pp. 185-190
Author(s):  
Karel Hrich ◽  
Bořivoj Groda
Keyword(s):  
Agricultural Land ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Cement Kiln ◽  
Reject Water ◽  
Sludge Drying ◽  
Dried Sludge ◽  
Organic Halogens

This work is focused on determination of adsorbable organic halogens (AOX) concentration in the digested sludge from the sewage treatment plant and the losses of this component during dewatering and drying of sludge. Drying of the sludge from wastewater treatment plant is not extended too much in Czech Republic. In this work, the AOX are monitored, because AOX is one of the limits restraining use of the sludge on an agricultural land. Another reason is technological demand for using the sludge in cement processing, because chlorine in AOX can cause decrease in a heat transfer effect in a cement kiln. It is clear from the results that both centrifuged and dried sludge from the sewage treatment plant Brno fulfilled limits for using sludge on agriculture land. They can also be composted, in case they meet other requirements. If not, it is a possibility of co-incineration in cement kiln. In such case, limit for total chlorine including the AOX is required too. This limit was not exceeded. Another aim was to calculate a mass balance of AOX during the centrifugation and drying processes. It was found out, that after centrifugation the main part of AOX remained in the centrifuged sludge (96.4 %). The rest was drawn-off with reject water. 60 % of AOX in the reject water were dissolved compounds. A similar situation occurred during the drying process. More than 99 % of AOX was bound in the dried sludge. The air and vaporised water contained such quantity of AOX, which corresponded with the amount of the dust in the air and the amount of particles of sludge in vaporised water.

Effectiveness of Wastewater Sludge Treatment Processes to Inactivate Parasites

1986 ◽  
Vol 18 (7-8) ◽  
pp. 397-404 ◽  
Author(s):  
R. S. Reimers ◽  
D. B. McDonell ◽  
M. D. Little ◽  
D. D. Bowman ◽  
A. J. Englande ◽  
...  
Keyword(s):  
Heat Treatment ◽  
The United States ◽  
Wastewater Sludge ◽  
Sludge Treatment ◽  
Treatment Processes ◽  
Sludge Digestion ◽  
Thermophilic Digestion ◽  
Sludge Drying ◽  
Aerobic And Anaerobic ◽  
Trichuris Vulpis

In the United States, Ascaris spp., Trichuris trichiura, Trichuris vulpis and Toxocara spp. are the most commonly found viable parasites in both treated and untreated municipal sludges. As expected, heat treatment, thermophilic digestion (aerobic and anaerobic) and thermophilic composting were effective in parasite inactivation, and with good sludge digestion (both aerobic and anaerobic), the effectiveness of sludge lagoon storage and sludge drying beds to inactivate parasites and pathogens is greatly enhanced. At present two commercial sludge processes, Chemfixation and Ozonics treatment have shown potential to inactivate parasites.

Microalgae growth for nutrient recovery from sludge liquor and production of renewable bioenergy

2011 ◽  
Vol 64 (6) ◽  
pp. 1195-1201 ◽  
Author(s):  
Bjorn Rusten ◽  
Ashish K. Sahu
Keyword(s):  
Wastewater Treatment ◽  
Treatment Plant ◽  
Gas Production ◽  
Wastewater Sludge ◽  
Light Transmittance ◽  
Algae Biomass ◽  
Methane Gas ◽  
Reject Water ◽  
Pre Treatment ◽  
The Impact

Proof-of-concept has been demonstrated for a process that will utilize nutrients from sludge liquor, natural light, and CO2 from biogas to grow microalgae at wastewater treatment plants. This process will reduce the impact of returning side-streams to the head of the plant. The produced algae will be fed to anaerobic digesters for increased biogas production. Dewatering of anaerobically digested sludge in centrifuges produces reject water with extremely low transmittance of light. A pre-treatment procedure was developed that improved light transmittance for reject water from the FREVAR, Norway, wastewater treatment plant from 0.1% T to 77% T (670 nm, 1 cm path). Chlorella sp. microalgae were found to be suitable for growth in this pre-treated reject water. Typical nitrogen removal was 80–90 g N/kg TSS of produced microalgae. The microalgae were successfully harvested by chemically assisted flocculation followed by straining through a 33 μm sieve cloth, achieving up to 99% recovery. Harvested algae were anaerobically co-digested with wastewater sludge. The specific methane gas production (mL CH4/g VS fed) for the algae varied from less than 65% to 90% of the specific methane gas production for the wastewater sludge, depending on digester temperature, retention time and pre-treatment of the algae biomass.

Exposure to dust, endotoxin and airborne microorganisms in wastewater sludge thermal drying units

2011 ◽  
Vol 64 (5) ◽  
pp. 1073-1080 ◽  
Author(s):  
O. Schlosser ◽  
A. Huyard ◽  
V. Catalán
Keyword(s):  
Personal Exposure ◽  
Wastewater Sludge ◽  
Thermophilic Actinomycetes ◽  
Monitoring Task ◽  
Inhalable Dust ◽  
High Emission ◽  
Exposure Levels ◽  
Low Levels ◽  
Sludge Drying ◽  
Dried Sludge

The objective of this study was to assess workers' exposure to bioaerosols in sludge drying units. Simultaneous collection of inhalable dust and airborne biological agents was carried out using rotating cup samplers (CIP 10, Arelco). Sixteen stationary and 30 personal measurements were performed in three drying plants, during summer and winter. Microbial content of air was characterized by high amounts of Gram-negative bacteria, endotoxin, and thermophilic actinomycetes. High differences between exposure levels were observed with regard to workplaces and tasks. Dryers and conveyors in operation were closed, and the monitoring task in the dryer room was associated with low levels of personal exposure, close to background levels. Conversely, cleaning and maintenance of the dryer and conveyors required the equipment to be opened, giving significantly higher task-based personal exposure levels. The fall of dried sludge into indoor containers resulted in high emission and spreading of dust. Mean personal exposure levels to fungi were moderate or low for all tasks. Based on the results of this study, appropriate means of operational control and personal protection are being developed and implemented on sites.

scholarly journals Particle balance and return loops for microplastics in a tertiary-level wastewater treatment plant

2021 ◽  
Author(s):  
Pauliina Salmi ◽  
Kalle Ryymin ◽  
Anna K. Karjalainen ◽  
Anna Mikola ◽  
Emilia Uurasjärvi ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Wastewater Sludge ◽  
Tertiary Level ◽  
Sludge Treatment ◽  
Reject Water ◽  
Exit Route ◽  
Sampling Campaign ◽  
The One

Abstract Microplastics (MPs) from households, stormwater, and various industries are transported to wastewater treatment plants (WWTPs), where a high proportion of them are captured before discharging their residuals to watersheds. Although recent studies have indicated that the removed MPs are mainly retained in wastewater sludge, sludge treatment processes have gained less attention in MP research than water streams at primary, secondary, and tertiary treatments. In this study, we sampled twelve different process steps in a tertiary-level municipal WWTP in central Finland. Our results showed that, compared to the plant influent load, three times more MPs circulated via reject water from the sludge centrifugation back to the beginning of the treatment process. Especially fibrous MPs were abundant in the dewatered sludge, whereas fragment-like MPs were observed in an aqueous stream. We concluded that, compared to the tertiary effluent, sludge treatment is the major exit route for MPs into the environment, but sludge treatment is also a return loop to the beginning of the process. Our sampling campaign also demonstrated that WWTPs with varying hydraulic conditions (such as the one studied here) benefit from disc filter–based tertiary treatments in MP removal.

scholarly journals Cost assessment of different routes for phosphorus recovery from wastewater using data from pilot and production plants

2017 ◽  
Vol 76 (2) ◽  
pp. 413-424 ◽  
Author(s):  
A. Nättorp ◽  
K. Remmen ◽  
C. Remy
Keyword(s):  
Treatment Plant ◽  
Wastewater Sludge ◽  
Phosphorus Recovery ◽  
Cost Data ◽  
Sludge Treatment ◽  
Wastewater Disposal ◽  
Treatment Train ◽  
P Recovery ◽  
Using Data ◽  
The Cost

Phosphorus (P) recovery from wastewater has considerable potential to supplement limited fossil P reserves. Reliable cost data are essential for investor and policymaker decisions. In this study, investment and operational costs for nine P recovery processes were calculated from the investor's perspective, taking into account all relevant side effects on the sludge treatment or the wastewater treatment plant. The assessment was based on pilot and full-scale data which were thoroughly consolidated and standardized with technical and cost data from the German wastewater–sludge treatment train to enable direct comparison. The cost influence of precipitation processes on the current wastewater–sludge treatment train ranges from −0.14 (generating profit) to 0.23 EUR per population equivalent (PE) and year, while the cost influence of sludge leaching processes is around 2.50 EUR/(PE y). The cost influence of processes using dry sludge and mono-incineration ash varies between 0.33 and 3.13 EUR/(PE y), depending on existing disposal pathways, mono-incineration, co-incineration or agricultural use of sludge. The specific costs per kg P recovered (−4 to 10 EUR/kg P) are in general higher than conventional fertilizer production (1.6 EUR/kg P). However, annual costs per PE represent less than 3% of the total costs for wastewater disposal.

Aerobic biological treatment of thermophilically digested sludge

2011 ◽  
Vol 63 (10) ◽  
pp. 2340-2345 ◽  
Author(s):  
M. V. Kevbrina ◽  
Y. A. Nikolaev ◽  
D. A. Danilovich ◽  
A. Ya. Vanyushina
Keyword(s):  
Retention Time ◽  
Biological Treatment ◽  
Hydraulic Retention Time ◽  
Treatment Plant ◽  
Ammonium Nitrogen ◽  
Wastewater Sludge ◽  
Optimal Conditions ◽  
Nitrogen And Phosphorus ◽  
Digested Sludge ◽  
Sludge Treatment

Aerobic biological treatment of digested sludge was studied in a continuously operated laboratory set-up. An aerated reactor was filled with thermophilically digested sludge from the Moscow wastewater treatment plant and inoculated with special activated sludge. It was then operated at the chemostat mode at different flow rates. Processes of nitrification and denitrification, as well as dephosphatation, occurred simultaneously during biological aerobic treatment of thermophilically digested sludge. Under optimal conditions, organic matter degradation was 9.6%, the concentrations of ammonium nitrogen and phosphate decreased by 89 and 83%, respectively, while COD decreased by 12%. Dewaterability of digested sludge improved significantly. The processes were found to depend on hydraulic retention time, oxygen regime, and temperature. The optimal conditions were as follows: hydraulic retention time 3–4 days, temperature 30–35 °C, dissolved oxygen levels 0.2–0.5 mg/L at continuous aeration or 0.7–1 mg/L at intermittent aeration. Based on these findings, we propose a new combined technology of wastewater sludge treatment. The technology combines two stages: anaerobic digestion followed by aerobic biological treatment of digested sludge. The proposed technology makes it possible to degrade the sludge with conversion of ∼45% volatile suspended solids to biogas, to improve nitrogen and phosphorus removal in reject water from sludge treatment units, and to achieve removal of malodorous substances after 8–9 days of anaerobic–aerobic sludge treatment.

scholarly journals A satellite-based analysis of the Val d'Agri (South of Italy) Oil Center gas flaring emissions

2014 ◽  
Vol 2 (6) ◽  
pp. 4101-4133 ◽  
Author(s):  
M. Faruolo ◽  
I. Coviello ◽  
C. Filizzola ◽  
T. Lacava ◽  
N. Pergola ◽  
...  
Keyword(s):  
Treatment Plant ◽  
Industrial Process ◽  
Environmental Complexity ◽  
Gas Flaring ◽  
Multi Temporal ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Pre Treatment ◽  
Infrared Data

Abstract. In this paper the Robust Satellite Techniques (RST), a multi-temporal scheme of satellite data analysis, was implemented to analyze the flaring activity of the largest Italian gas and oil pre-treatment plant (i.e. the Ente Nazionale Idrocarburi – ENI – Val d'Agri Oil Center – COVA). For this site, located in an anthropized area characterized by a~large environmental complexity, flaring emissions are mainly related to emergency conditions (i.e. waste flaring), being the industrial process regulated by strict regional laws. With reference to the peculiar characteristics of COVA flaring, the main aim of this work was to assess the performances of RST in terms of sensitivity and reliability in providing independent estimations of gas flaring volumes in such conditions. In detail, RST was implemented on thirteen years of Moderate Resolution Imaging Spectroradiometer (MODIS) medium and thermal infrared data in order to identify the highly radiant records associated to the COVA flare emergency discharges. Then, exploiting data provided by ENI about gas flaring volumes in the period 2003–2009, a MODIS-based regression model was developed and tested. Achieved results indicate that such a model is able to estimate, with a good level of accuracy (R2 of 0.83), emitted gas flaring volumes at COVA.

scholarly journals BIOCHAR AS AN ECO-ADDITION IN WASTEWATER AND WASTEWATER SLUDGE TREATMENT PROCESSES IN NON-URBANIZED AREAS

2019 ◽  
Vol 1 (2) ◽  
pp. 1-14
Author(s):  
Mazurkiewicz Jakub ◽  
Damian Janczak ◽  
Dawid Wojcieszak ◽  
Sebastian Kujawiak ◽  
Przemysław Zakrzewski
Keyword(s):  
Wastewater Treatment ◽  
New Products ◽  
Treatment Plant ◽  
Wastewater Sludge ◽  
Stable Carbon ◽  
Sludge Treatment ◽  
Waste Products ◽  
Treatment Processes ◽  
Management Processes ◽  
Urbanized Areas

Especially in non-urbanized areas there is a need to use various waste products, e.g. from agriculture, households, etc. New products that are created in a simple way should be able to be used many times without the use of complicated and expensive technology. This article presents the potential of biochar used in wastewater treatment processes and sludge management in small installations - for the maximum maintained number of users equal to 50. The possibilities of two substances used in sewage management processes, such as char and biochar will be presented. These substances, produced from pyrolysis, are stable carbon-rich compounds which have various beneficial applications like soil conditioning, remediation and wastewater treatment. In particular, biochar originating from wastewater sludge pyrolysis, possible to be generated at the place of formation, was taken into account. In addition, ways to increase the reliability of the treatment plant with biochar based filters are described.

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