Energy Recovery from Sewage Sludge: The Case Study of Croatia (original) (raw)

Sewage sludge energy recycling

Ecological Chemistry and Engineering. S = Chemia i Inżynieria Ekologiczna. S

Development of wastewater treatment systems causes a systematic growth of the amount of sewage sludge. In 1999, about 350 000 Mg d.m. sludge was generated in Poland, and for the year 2010 this amount is predicted to be doubled. Agricultural application of sludges, in particular these coming from wastewater treatment plants in big cities, is very controversial because of a growing content of heavy metals, organic micropollutants and pathogens. The binding legal conditions cause that also sludge disposal will be limited in the nearest future. In this situation and increasing interest in thermal methods-sludge energy recycling is expected. In this paper, the most important technologies of drying and incineration of sewage sludge offered on the Polish market are discussed and compared from the point of view of ecological safety and economic and energy indices. Main operation parameters, advantages and disadvantages of these technologies are presented..

Alternatives of Domestic Wastewater Sludge Drying Processes for Energy Recovery : A Review

Revista de Engenharia Térmica

As communities grow, cities need to increase their capacity to collect and treat domestic wastewater. The need of larger domestic wastewater treatment plants and proper disposal of its solid waste has attracted the scientific community to research about new technologies that will use those systems and waste as a way to generate energy. The moisture content of a fuel effects the combustion products and the energy released by the reaction. Therefore, in order to make biomass to be a viable fuel option, the technological and scientific challenges of the drying process of wastewater sludge must be faced and overcome so the lowest moisture content level is achieved. Conventional drying processes as for example, direct and indirect thermal drying, are commonly used. However, other processes using renewable energy as for example solar drying are also being studied by the scientist around the world. Moisture content, physical-chemical properties as for example, heating values, composition,...

Solar drying in sludge management in Turkey

Renewable Energy, 2007

Two main wastewater treatment plants in Bursa city in Turkey will start to operate and produce at least 27,000 tons of dry solids per year by the end of 2006. The purpose of this study was to investigate an economical solution to the sludge management problem that Bursa city would encounter. The general trend in Turkey is mechanical dewatering to obtain a dry solid (DS) content of 20%, and liming the mechanically dewatered sludge to reach the legal landfilling requirement, 35% DS content. This study recommends limited liming & solar drying as an alternative to onlyliming the mechanically dewatered sludge. Open and covered solar sludge drying plants were constructed in pilot scale for experimental purposes. Dry solids and climatic conditions were constantly measured. Faecal coliform reduction was also monitored. The specially designed covered solar drying plant proved to be more efficient than the open plant in terms of drying and faecal coliform reduction. It was found that, if the limited liming & solar drying method was applied after mechanical dewatering instead of only-liming method, the total amount of the sludge to be disposed would be reduced by approximately 40%. This would lead to a reduction in the transportation, handling, and landfilling costs. The covered drying system would amortize itself in 4 years. r

Sewage Sludge Solar Drying: Experiences from the First Pilot-Scale Application in Greece

Increasingly strict regulations governing sludge management have raised interest in drying technologies. The feasibility of sewage sludge solar drying was experimentally evaluated in a 66-m 2 pilotscale greenhouse plant under typical weather conditions in Greece. The greenhouse was equipped with ventilation fans to maximize the drying process efficiency and a turning drum for efficient sludge mixing. The obtained results proved the applicability and the high performance of the solar drying technology. The time necessary to achieve a dry product with a dry solids content up to 95% ranged between 8 and 31 days, depending on the weather conditions. During drying, sludge organic matter was reduced by 5-21%, and total and fecal coliform content was also decreased up to three orders of magnitude. By taking into consideration the sludge content in heavy metals, the final product can partially or totally replace commercially available inorganic fertilizers in agricultural applications, in accordance with the restrictions imposed by national and European regulations. Based on a preliminary cost analysis concerning the construction of a solar drying facility covering a sum of 80,000 population equivalent (PE), a corresponding capital cost of 24 4/PE is anticipated.

Opportunities regarding the use of technologies of energy recovery from sewage sludge

2021

Based on the global need to efficiently eliminate highly produced amounts of sewage sludge, alternative technologies are required to be practically developed. Reduction of sewage sludge waste quantities with energy recovery is the most important and modern practice, with least possible impact on the environment. Appropriate technologies for treating and disposal sewage sludge are currently considered: incineration, gasification and pyrolysis. The main products generated during the pyrolysis process are bio-gas, bio-oil and bio-residue, providing sustainable fuels/ biofuels and adsorbents. Compared to other disposal methods of sewage sludge, pyrolysis has advantages in terms of the environment: waste in small quantities, low emissions, low level of heavy metals. From a technological point of view, pyrolysis is the most efficient in relation to its final products, pyrolysis oil, pyrolysis gas and solid residue that can be transformed into CO2 adsorbent with the help of chemical and th...

An experimental examination of energy production from domestic-based waste water treatment sludge

World Journal of Engineering, 2015

In Turkey, treatment sludge that obtained from domestic wastewater and water treatment plants causes storage and disposal problems. In the current situation, there are 69 domestic wastewater treatment plants in Turkey and this corresponds to approximately 13% of the population. Total 500 thousand tons of treatment sludge is released from these treatment plants, annually. In the case of all municipalities establish a wastewater treatment plant in Turkey, approximately, 4 million tons of treatment sludge is projected to release in a year. Additionally, 3.6 million tons of treatment sludge will be obtained from the manufacturing industry. In other words, approximately 7.6 ↔ 106 tons of treatment sludge potential exists in Turkey and in the same amount of the storage area (7.6 ↔106m3) is needed for the storage of this treatment sludge, perennially. In this study, energy production from wastewater treatment sludge through the anaerobic method has been investigated and compared to the aer...

An Evaluation of Sludge-to-Energy Recovery Methods

2018

Due to rapidly population growth, the increasing volume of sewage sludge from wastewater treatment facilities is becoming a prominent concern globally. The disposal of this sludge is particularly challenging due to the high content of organic, toxic and heavy metal pollutants in its constituents which poses severe environmental hazard. The use of this waste as a valuable energy resource represents an innovative stride in the achievement of a circular low carbon economy. However, the deterring properties of sewage sludge as a fuel is its high moisture and ash content which differentiates it from other solid fuels and complicates its thermal conversion. This study presents a simple analysis of four sewage to energy recovery routes (anaerobic digestion, combustion, pyrolysis and gasification) with emphasis on recent developments in research, benefits and limitations of the technology and future research considerations to ensure cost and environmentally viable sewage to energy pathway. ...

ENERGY PRODUCTION FROM THE SLUDGE OF A SEWAGE TREATMENT STATION (Atena Editora)

ENERGY PRODUCTION FROM THE SLUDGE OF A SEWAGE TREATMENT STATION (Atena Editora), 2022

The world population grows exponentially, and Brazil is no different. Thus, we increasingly need natural resources; and, as a consequence, there is an increase in waste production. Brazil, a few years ago, developed its National Solid Waste Policy (PNRS) through Law No. 12,305/10, where, regardless of its origin, solid waste must be disposed of properly, minimizing possible environmental damage; while CONAMA Resolution 375/06 already defined the proper disposal of sewage sludge to protect the environment and the health of the population. However, some of these residues have a significant energy value in their reuse, as is the case of urban sewage sludge. In this context, the present work aimed to evaluate the production of biogas energy from the sludge of a Sewage Treatment Station (ETE). Therefore, the collection and characterization of the sludge from the ETE was carried out by measuring pH, electrical conductivity, determination of total solids, fixed and volatile, determination of chemical and biochemical oxygen demand. The anaerobic digestion process with control of pH, temperature, pressure and mechanical agitation was carried out for 25 days, with an expressive generation of biogas being observed. Therefore, this residue, as biomass for energy production, proved to be an alternative with considerable energy potential, in addition to being an option for the proper disposal of solid waste and environmentally sustainable.

Energy Production from Sewage Sludge in a Proposed Wastewater Treatment Plant

The implemented technologies for sewage sludge processing are still very limited in Egypt. Unfortunately, dealing with the produced sludge is mainly given to the drying process through natural drying beds neglecting quality of the dried sludge. The undertaken work is devoted to provide a design proposal for a typical wastewater treatment plant suitable for the small communities on a very limited area of land compared to that required to construct the conventional treatment plant that serves the same population. The proposed sewage treatment plant is certainly beneficial in reducing the capital costs by 26%, in addition to about 20% reduction in the running costs. On the other hand, electricity generated from energy produced by anaerobic digestion of sewage sludge reduces the electrical power requirements from the main grid network to about 27% in the proposed wastewater treatment plant.