Thermal dehydration of urban biosolids with green liquor dregs from pulp and paper mill

Gomes, Luciano A.; Santos, Andreia F.; Góis, José C.; Quina, Margarida J.

doi:10.1016/j.jenvman.2019.109944

Cited by 11 publications

(7 citation statements)

References 50 publications

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“…Thus, it is essential to find a strategy to reduce energy requirements. In this context, industrial wastes (e.g., coal fly ash and green liquor dregs) have been used as drying adjuvants (Gomes et al, 2020).…”

Section: Economic Innovationsmentioning

confidence: 99%

Economic and Technological Principles of Safe Use of Sewage Sludge in Agriculture

Muter¹

2022

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Topicality. Spreading the philosophy of sustainable development, where activities preserve natural and social resources for use by future generations without harming the business economy, as well as significant increases in the price of chemical fertilizers due to rising gas prices require ways to reduce the chemical burden on agriculture. The trend of abandoning intensive technologies will be exacerbated by economic leverage - European Union regulations are increasingly banning agrochemicals and introducing a "carbon tax". Therefore, the use of sewage sludge as fertilizer for agricultural production is becoming an urgent issue. Therefore, the use of sewage sludge as fertilizer for agricultural production on the basis of economic efficiency is becoming an urgent issue.Aim and tasks. The aim of the article is to consider the economic and technological principles aimed at improving the bioavailability of nutrients and reducing the risk of using biowaste before entering the soil, in the context of the idea of sustainable development.Research results. Sewage sludge (SS) application in agriculture has a beneficial effect on soil organic matter content, sorption capacity and an overall improvement in physical properties. Conversion of SS to a soil amendment can be performed by a broad spectrum of methods, which greatly differ by substrate/amendment composition, treatment time, and physicochemical conditions. Sanitary and epidemiological safety is essential, which is why bio-wastes require processing according to selected technologies that aim to improve the bioavailability of nutrients and reduce hazards before entering the soil. This review provides a more complete overview of the present status of the methods for SS disinfection. The review is focused on i) environmental and legislative aspects of SS application in agriculture; ii) risk factors related to the abundance of bacterial, viral, protozoan and other pathogens in SS and methods of SS hygienization by various physical and chemical treatments; iii) risks of soil pollution with biologically active compounds (e.g., antibiotic resistance genes and other emerging contaminants). For the life cycle assessment, an environmental performance and pathogen risk was considered. The results of such consideration have direct impact on the nature of the applied economic and technological measures. Conclusions and perspectives in this field were formulated, using 102 references, including 49 citations dated by the last five years.Conclusion. Numerous technological approaches on SS treatment have their particular advantages, although disinfection efficiency remains unsatisfactory. Legislative requirements are still based on less resistant indicator organisms. Further comprehensive research on SS treatment should be focused on combination of different physical (especially, thermal) and chemical processes, which would convert SS into a qualitative fertilizer with safe microbiological characteristics. The decrease in energy consumption during drying and the reduction of the management costs of these residues can be relevant economic gains. In general, the application of drying to remove water from sewage sludge should be a balance between energy costs in the process and the management costs without drying.

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Section: Economic Innovationsmentioning

confidence: 99%

Economic and Technological Principles of Safe Use of Sewage Sludge in Agriculture

Muter¹

2022

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“…Nevertheless, further studies are ongoing to use of GLD combined with the drying process to facilitate the sanitation of highly contaminated samples. In fact, a recent study also showed that GLD can have a positive effect on drying efficiency [33].…”

Section: Sanitation Effect Of Chemical Treatmentmentioning

confidence: 99%

Effect of Thermal Drying and Chemical Treatments with Wastes on Microbiological Contamination Indicators in Sewage Sludge

Santos

Matos

et al. 2020

Microorganisms

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This work aims to evaluate the microbiological contamination of sewage sludge (SS) collected in urban wastewater treatment plants (WWTP) from Portugal. Two types of SS were considered: urban mixed (UM) and from anaerobic digestion (AD). The two types of samples were characterized in relation to the main physical and chemical parameters, as well as the microbiological contamination (Escherichia coli and Salmonella spp). Then, sanitation tests were conducted through thermal drying and chemical treatments. Towards a circular economy, industrial alkaline wastes (green liquor dregs -GLD, lime mud, coal fly ash, eggshell) were tested as alternatives to lime. Only six out of nineteen samples complied with the legal limits for both microorganisms. However, drying at 130 • C sanitized selected samples below the E. coli limit, regardless of the initial moisture or contamination. Additionally, CaO (obtained from eggshell) led to the complete elimination of E. coli at any dosage studied (0.05-0.15 g/g SS wet basis ). GLD evidenced the ability to reduce E. coli contamination at room temperature, but not enough to comply with the legal limit. In general, this work highlights the need to sanitize the SS before its application to the soil, and the positive role of some wastes on this goal.

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“…The modernization and construction of new WWTP to treat and return water to the environment is a key factor to the increase in SS production worldwide, with an estimated production of 13 Mt (dry basis) in the European Union in 2020 [4]. Within the different alternatives to manage SS, its application to soil is still a primary route, although this lacks consensus within the scientific community and among stakeholders [4]. The main advantage of land spreading is the possibility of recycling OM and macronutrients (mainly N and P) to the soil.…”

Section: Introductionmentioning

confidence: 99%

“…Although composting of SS is one of the preferable options to stabilize organic matter and decontamination, thermal drying is arising as a viable option to obtain a consistent product to be applied in the soil [4,13,14]. Indeed, the present study is part of a project (Dry2Value) that aims to develop an industrial dryer to be implemented in WWTP to facilitate subsequent SS management phases, such as reducing transport costs and odors.…”

Section: Introductionmentioning

confidence: 99%

“…Although the removal of moisture content by thermal drying is a costly process, the implementation of this step must be a balance between the cost of energy for drying and the reduction of the final cost for transportation and storage. Moreover, our previous studies explore the feasibility of using waste materials as drying additives to assist the drying process with energy gains, sanitize the SS, and balance the final product with additional micronutrients [4,13,14]. The selection of the best additive for the application in a full-scale drying process to produce an organic soil amendment was addressed in our previous study [15].…”

Section: Introductionmentioning

confidence: 99%

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Greenhouse Assays with Lactuca sativa for Testing Sewage Sludge-Based Soil Amendments

Santos

Veríssimo²,

Brites³

et al. 2022

Agronomy

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Sustainable agriculture practices within the guidelines of nutrient recycling and the circular economy must be increasingly promoted. This work aims to evaluate the performance of dried sewage sludge (DSS), green liquor dregs mixed with sewage sludge (DSSA), raw sewage sludge, and commercial organic fertilizer control, using a short-term agronomic assessment with lettuce crop (Lactuca sativa) in greenhouse conditions. Different application rates based on the nitrogen content were tested for each soil amendment: 0, 85, 170, and 225 kg N/ha (treatments T0, T1, T2, and T3, respectively). DSS and DSSA resulted in fresh lettuce productivities 1.3 and 3.2 times higher in T3 than in T0, respectively. The ideal N content in lettuce leaves was reached for all materials and treatments, with the highest values obtained for DSS (2.88–3.33% from T1 to T3). Lettuce produced in soils amended with DSS and DSSA showed also ideal levels of Ca. Overall, the performance of sludge-based products was similar to commercial fertilizer, without impairing the nutritional balance of the crop and the soil.

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Thermal dehydration of urban biosolids with green liquor dregs from pulp and paper mill

Cited by 11 publications

References 50 publications

Economic and Technological Principles of Safe Use of Sewage Sludge in Agriculture

Economic and Technological Principles of Safe Use of Sewage Sludge in Agriculture

Effect of Thermal Drying and Chemical Treatments with Wastes on Microbiological Contamination Indicators in Sewage Sludge

Greenhouse Assays with Lactuca sativa for Testing Sewage Sludge-Based Soil Amendments

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