Improvement of a conventional activated sludge process using a hybrid moving bed system

The regulatory requirements of the European Directive91/271/EEC about urban wastewater treatment make itnecessary to improve the efficiency of many wastewatertreatment plant (WWTP) built in Europe in recent decades.In this research, the benefits of the use of the innovativetechnology of moving bed in a conventional activatedsludge were studied. The research compared the differencesin organic matter removal between both systemsin two equal pilot plants with settler as physical separationsystem: a conventional activated sludge system anda hybrid moving bed which part of the biomass attachedin the carriers. The study showed that at low feed/massloading, moving bed system is able to remove an additional43.33% of BOD5 and an additional 30.08% of COD.So, an existing plant of low feed/mass loading activatedsludge with an effluent of 30±5 mgO2/L of BOD5 could berestored with a hybrid moving bed getting an effluent of17±2 mgO2/L of BOD5

A Review of the Energy Potential of Residual Biomass for Coincineration in Kazakhstan

Although it has access to hydrocarbon reserves, Kazakhstan has developed a strategy for the transition to a low-carbon economy, which should include the use of renewable energy sources. In this framework, the use of biomass from waste could have the potential to reduce emissions from traditionally fueled energy generation, as well as adding value to the generated waste, which also improves waste management according to the principles of a circular economy. The analysis of the resources and energy potential from residual biomass in Kazakhstan presents an annual production of 37.26 106 tons of residual biomass, which could be capable of producing an energy potential of 466.74 PJ/year, little more than half to the total production from all the installed power plants in the country. Agricultural, animal and municipal solid waste are available to produce energy in Kazakhstan based on combustion technologies; however, animal waste and agricultural are the main potential sources with 61.02% and 38.34% of the theoretical total biomass potential energy analyses, respectively. Considering that 80% of Kazakhstan’s electricity generation comes from coal-fired plants, energy from agriculture could be co-fired for the gradual replacement of coal with biomass in operational power plants, without substantially increasing costs or infrastructure investments, thereby making the transition to a low-carbon economy and renewable energy sources in the country easier.Government of the Republic of Kazakhstan Ministry of Education and Science of the Republic of Kazakhstan AP14871168 AP14870834research group TEP-968 (Technologies for Circular Economy) of the University of Granad

An overview of agro‑food industry wastewater treatment: a bibliometric analysis and literature review

Agro-food (AF) industry provides great investment opportunities in its treated water and solid wastes, by conversion into value-added products. Our study accumulated extensive bibliometric data on this field from the Scopus database, between 1974 and 2021, and conducted a scientometric analysis using Science Mapping Analysis Software Tool (SciMAT) and VOSviewer for analyzing the retrieved data. The leading journals, highly used keywords in the published articles, authors and papers with the highest citations, and relevant regions were all identified in the scientometric analysis. Goal 6 of the Sustainable Development Goals (SDGs) pledge to “ensure the availability and sustainable access to water and sanitation for all.” To fulfill this demand, decentralized technologies are being developed. The scientometric analysis found significant flaws in previous studies on the adoption and use of decentralized treated AF wastewater, as well as its potential benefits for a sustainable future, particularly in the developing countries. Coagulation/electrocoagulation/ultrasonic processes, hybrid constructed wetlands and microbial inoculation are emerging efforts to achieve SDG6, particularly, in the emerging economy nations. Our scientometric findings can help academics collaborate on research, form joint ventures, and implement sophisticated technologies for treating AF wastewater and producing beneficial byproducts.Science and Technology Development Fund (STDF) 33534Egyptian Knowledge Bank (EKB

Recycling Organic Fraction of Municipal Solid Waste: Systematic Literature Review and Bibliometric Analysis of Research Trends

The authors appreciate the support of the research group TEP-968 (Technologies for Circular Economy) of the University of Granada.The organic fraction is usually the predominant fraction in municipal solid waste, so its recycling is a potential alternative to disposal in landfill sites, as well as helping to reach targets included in the European Circular Economy Package. The existing body of knowledge in this research field is very large, so a comprehensive review of the existing scientific literature has been considered of interest to provide researchers and professionals with a detailed understanding of the status quo and predict the dynamic directions of this field. A systematic literature review and bibliometric analysis have been performed to provide objective criteria for evaluating the work carried out by researchers and a macroscopic overview of the existing body of knowledge in this field. The analysis of 452 scientific articles published from 1980 to 2019 has shown that the application of composting technologies is relevant, especially since 2014, when policies aimed at reducing emissions to the atmosphere were increased and focused on the use of this waste fraction to produce biogas. Nevertheless, the scientific field is still evolving to impose a model of a circular economy; in fact, emerging studies are being conducted on the production of biomethane, contributing to the decarbonised energy system.Research group TEP-968 (Technologies for Circular Economy) of the University of Granad

Model of Suspended Solids Removal in the Primary Sedimentation Tanks for the Treatment of Urban Wastewater

Primary settling tanks are used to remove solids at wastewater treatment plants and are considered a fundamental part in their joint operation with the biological and sludge treatment processes. The aim of this study was to obtain a greater understanding of the influence of operational parameters, such as surface overflow rate, hydraulic retention time, and temperature, on the removal efficiency of suspended solids and organic matter by the measurement of chemical oxygen demand and biochemical oxygen demand in the primary sedimentation process. The research was carried out in a semi-technical primary settling tank which was fed with real wastewater from a wastewater treatment plant. The physical process was strictly controlled and without the intervention of chemical additives. Three cycles of operation were tested in relation to the surface overflow rate, in order to check their influence on the different final concentrations. The results obtained show that the elimination efficiency can be increased by 11% for SS and 9% for chemical oxygen demand and biochemical oxygen demand, for variations in the surface overflow rate of around ±0.6 m3/m2·h and variations in hydraulic retention time of around ±2 h. The results also show that current design criteria are quite conservative. An empirical mathematical model was developed in this paper relating SS removal efficiency to q, influent SS concentration, and sewage temperature

Multi-Parametric Analysis Based on Physico-Chemical Characterization and Biochemical Methane Potential Estimation for the Selection of IndustrialWastes as Co-Substrates in Anaerobic Digestion

This work was supported by EMASAGRA S.A. thanks to the grant number 13 included in the Program INICIATC-INNCUBA CAJASUR-UG

Waste to Energy from Municipal Wastewater Treatment Plants: A Science Mapping

Energy recovery, according to circular economy and sustainable principles, has established itself as an inevitable field of action in wastewater treatment plants (WWTPs). Energy costs are forcing the optimization of processes and increases in the development of applicable waste-to-energy (WtE) technologies. This study aims to analyze the existing knowledge on WtE research in municipal WWTPs using a systematic literature review and a bibliometric analysis from 1979 to 2021. For this purpose, Science Mapping Analysis Tool (SciMAT) and VosViewer, two softwares for analyzing performance indicators and visualizing scientific maps, were used to identify the most relevant figures in the research. The results show an exponential increase in the number of publications over time, which has yet to reach a stage of maturity. The analysis of the evolution of the topics exposes variability in the keywords over the years. The main field of WtE research has focused on sludge treatment, with technologies ranging from anaerobic digestion to more recently-emerging ones such as microalgae or membrane technologies. The analysis also identified the need for more publications on other wastes in WWTPs, which are necessary to achieve zero waste.EMASAGRA S.A 432

The Study of Economic and Environmental Viability of the Treatment of Organic Fraction of Municipal Solid Waste Using Monte Carlo Simulation

Valorization of municipal solid waste (MSW) plays a crucial role in a sustainable society and provides an opportunity to reduce carbon emissions. The economic and social viability of the treatment of the organic fraction of MSW (OFMSW) with a multi-scenario analysis (composting and anaerobic digestion for renewable electricity or for biomethane injection into natural gas networks) was studied using a Monte Carlo simulation. The cost of treating organic fraction of MSW to neutralize financial net present value (NPV) and social NPV through greenhouse gas emissions avoided was determined for each scenario. The costs considered were the investment and the operating and maintenance costs. The financial benefits from the revenue of subproducts depended on the scenario. The lowest average fee to neutralize the financial NPV was 6.38 ¿/tonne treated in anaerobic digestion for biomethane injection into natural gas networks, therefore, it was the most financially viable. The average social NPV calculated for biomethane injection into natural gas networks (16.60 ¿/tonne) was higher than that obtained for renewable electricity (13.59 ¿/tonne). According to the results, anaerobic digestion for biomethane injection into natural gas networks is the most socially and economically viable alternative for the treatment of OFMSW.University of Granada TEP-96

Study of the Potential for Agricultural Reuse of Urban Wastewater with Membrane Bioreactor Technology in the Circular Economy Framework

The growing demand for water by the population and industry, as well as water scarcity due to climate change, has created a need to reuse treated water for agricultural purposes. In this context, the European Union, through its Regulation (EU) 2020/741, establishes minimum requirements for wastewater reuse, specifying that reuse for agricultural purposes can help to promote the circular economy and reduce the need for fertiliser use by setting high-quality standards. The aim of this article is to study whether the treated water from a pilot plant with membrane bioreactor technology operating with real urban wastewater from the city of Granada (Spain) satisfies the quality standards required for its reuse for agricultural purposes, as well as assessing the use of other resources produced during wastewater treatment, such as biogas and biostabilised sludge. This plant works in four cycles of operation at two different hydraulic retention times (6 and 12 h) and different concentrations of mixed liquor (2429–6696 mg/L). The pilot plant consists of a membrane bioreactor where there are four ultrafiltration membranes working in continuous operation and a sludge treatment line working in discontinuous mode. Subsequently, a tertiary treatment of advanced oxidation process was applied to the treated water for a time of 30 min, with different concentrations of oxidant. The results showed that the effluent has sufficient quality to be used in agriculture, complying with the characteristics established in the European legislation. Furthermore, the biostabilised sludge and biogas can be potentially reusable.Spanish Government RTI2018-101270-B-I0

Analyzing the production, quality, and potential uses of solid recovered fuel from screening waste of municipal wastewater treatment plants

Over time, wastewater management evolves into a circular model, producing energy and moving towards zero waste. The usual screening waste treatment is the elimination, with no energy recovery processes. As an alternative, the production of solid recovered fuel (SRF) from screening has been studied, both non-densified and densified, in pellet form. The densification was developed, taking as variables the input moisture and size of the die, obtaining 20 different samples. The optimum pelletizing conditions are an input moisture content of 10% and dies with a compression ratio of 6/20, 6/24 and 8/32. SRF properties have been evaluated based on a quality proposal presented in this paper, which has been developed given the lack of uniformity in the existing SRF standards. The SRF produced complies with fuel quality requirements, such as lower calorific value, with values between 13.37 and 25.65 MJ/kg; Cl and Hg content, with maximums of 0.066% and 1.0 × 10����� 5 mg/MJ, respectively; and ash content, between 7.22% and 9.85%. Energy from waste plants could be the destination for all the SRF produced. Its use in cement plants and gasification processes, more restrictive than the previous one, would require manufacturing processes with adequate moisture levels and die size.EMASAGRA 4325University of Granada / CBU