Cost of Urban Wastewater Treatment and Ecotaxes: Evidence from Municipalities in Southern Europe

Comparing the performance of microbial electrochemical assisted and aerated treatment wetlands in pilot-scale: Removal of major pollutants and organic micropollutants

The combination of treatment wetlands (TWs) with microbial electrochemical technologies (MET) is often studied in the lab to improve the performance and decrease the footprint of TWs. In this article we evaluated the long-term performance of four pilot-scale vertical sub-surface flow TWs for major pollutants' and organic micropollutants' removal from domestic wastewater. Three of them were filled with electroconductive material and operated under saturated (MET SAT), unsaturated (MET UNSAT) and unsaturated-saturated (MET HYBRID) conditions while the fourth one was a saturated intensified aerated system (AEW) filled with gravel. The MET-TWs achieved significant removals of COD (>78 %) with no clogging issues at the maximum applied OLR (249 g COD m-3 d-1) while under these loading conditions TSS removal exceeded 84 %. Among all electroactive TWs, UNSAT could remove 25 g NH4-N m-3 d-1 through nitrification when peak ammonium loading rate was applied; however this removal was significantly lower than AEW (35 g NH4-N m-3d-1). No important removal of P was observed in all systems with the exception of MET-SAT were precipitation reactions of P with iron occurred when anaerobic pretreated wastewater was used. The removal of the sum of studied organic micropollutants ranged between 70 ± 18 % (MET UNSAT) to 91 ± 4 % (AEW) and improved with feeding pulses increase. Moderate to high removal of specific microcontaminants was observed depending on the target compound, the studied system and the operational conditions. AEW and MET HYBRID systems complied with the limits set by EU for wastewater discharge to non-sensitive water bodies and for Class B water reuse. Scale-up calculations for a settlement of 500 PE showed that these systems require much less area per PE (0.51 m2 PE-1) comparing to conventional TWs while the operational cost was calculated to 0.07 € m-3 for the AEW and 0.02 € m-3 for the MET HYBRID.

Modeling Free Nitrous Acid Inhibition on the Removal of Nitrogen and Atenolol during Sidestream Partial Nitritation Processes

Sidestream serves as an important reservoir collecting pharmaceuticals from sludge. However, the knowledge on sidestream pharmaceutical removal is still insufficient. In this work, atenolol biodegradation during sidestream partial nitritation (PN) processes characterized by high free nitrous acid (FNA) accumulation was modeled. To describe the FNA inhibition on ammonia oxidation and atenolol removal, Vadivelu-type and Hellinga-type inhibition kinetics were introduced into the model framework. Four inhibitory parameters along with four biodegradation kinetic parameters were calibrated and validated separately with eight sets of batch experimental data and 60 days' PN reactor operational data. The developed model could accurately reproduce the dynamics of nitrogen and atenolol. The model prediction further revealed that atenolol biodegradation efficiencies by ammonia-oxidizing bacteria (AOB)-induced cometabolism, AOB-induced metabolism, and heterotrophic bacteria-induced biodegradation were 0, ∼ 60, and ∼35% in the absence of ammonium and FNA; ∼ 14, ∼ 29, and ∼28% at 0.03 mg-N L-1 FNA; and 7, 15, and 5% at 0.19 mg-N L-1 FNA. Model simulation showed that the nitritation efficiency of ∼99% and atenolol removal efficiency of 57.5% in the PN process could be achieved simultaneously by controlling pH at 8.5, while 89.2% total nitrogen and 57.1% atenolol were removed to the maximum at pH of 7.0 in PN coupling with the anammox process. The pH-based operational strategy to regulate FNA levels was mathematically demonstrated to be effective for achieving the simultaneous removal of nitrogen and atenolol in PN-based sidestream processes.

Advancements and sustainable strategies for the treatment and management of wastewaters from metallurgical industries: an overview

Metallurgy is pivotal for societal progress, yet it yields wastewater laden with hazardous compounds. Adhering to stringent environmental mandates, the scientific and industrial sectors are actively researching resilient treatment and disposal solutions for metallurgical effluents. The primary origins of organic pollutants within the metallurgical sector include processes such as coke quenching, steel rolling, solvent extraction, and electroplating. This article provides a detailed analysis of strategies for treating steel industry waste in wastewater treatment. Recent advancements in membrane technologies, adsorption, and various other processes for removing hazardous pollutants from steel industrial wastewater are comprehensively reviewed. The literature review reveals that advanced oxidation processes (AOPs) demonstrate superior effectiveness in eliminating persistent contaminants. However, the major challenges to their industrial-scale implementation are their cost and scalability. Additionally, it was discovered that employing a series of biological reactors instead of single-step biological processes enhances command over microbial communities and operating variables, thus boosting the efficacy of the treatment mechanism (e.g., achieving a chemical oxygen demand (COD) elimination rate of over 90%). This review seeks to conduct an in-depth examination of the current state of treating metallurgical wastewater, with a particular emphasis on strategies for pollutant removal. These pollutants exhibit distinct features influenced by the technologies and workflows unique to their respective processes, including factors such as their composition, physicochemical properties, and concentrations. Therefore, it is of utmost importance for customized treatment and disposal approaches, which are the central focus of this review. In this context, we will explore these methods, highlighting their advantages and characteristics.

Application of response surface methodology for COD and ammonia removal from municipal wastewater treatment plant using acclimatized mixed culture

This study aimed to optimize conditions influencing the removal of chemical oxygen demand (COD) and ammonia-N in municipal wastewater by using acclimatized mixed culture (AMC). Two-level factorial analysis was used to investigate the factors affecting the degradation of COD and ammonia-N (%); ratio of synthetic wastewater (SW) to acclimatized mixed culture (AMC) (1:1 and 3:1), presence and absence of support media (Yes and No), agitation (0 rpm and 100 rpm) and hydraulic retention time (HRT) (2 and 5 days). A central composite design (CCD) under response surface methodology (RSM) determined the optimum agitation (0 rpm and 100 rpm) and retention time (2 and 5 days). The best conditions were at 3:1 of SW: AMC ratio, 100 rpm agitation, without support media, and 5 days retention time. COD and ammonia-N removal achieved until 57.23% and 43.20%, respectively. Optimization study showed the optimum conditions for COD and ammonia-N removal were obtained at 150 rpm agitation speed and 5 days of retention time, at 70.41% and 64.29% respectively. This study discovers the conditions that affect the COD and ammonia-N removal in the municipal wastewater using acclimatized mixed culture.

•

Removal of COD and ammonia-N using acclimatized mixed culture.

•

Central composite design was used to optimize process condition.

•

The maximum COD removal was found to be 70.41%.

•

The maximum ammonia-N removal was found to be 64.29%.

Piggery wastewater treatment with algae-bacteria consortia: Pilot-scale validation and techno-economic evaluation at farm level

The efficiency of an outdoor pilot-scale raceway pond treating the wastewaters generated by a large-scale piggery farm in Northern Italy was evaluated. The biomass productivity over 208 days of experimentation was 10.7 ± 6.5 g TSS·m^-2·d^-1, and ammoniacal nitrogen, orthophosphate, and COD average removal efficiencies were 90%, 90%, and 59%, respectively. Results were used to perform a comprehensive techno-economic analysis for integrating algae-based processes in farms of different sizes (100-10000 pigs). The amount of N disposed of on agricultural land could be reduced from 91% to 21%, increasing the fraction returned to the atmosphere from 2.4% to 63%, and the fraction in the biomass from 6.2% to 16%. For intensive farming, the release of 110 t N·ha^-1·y^-1 contained in the digestate could be avoided by including algae-bacteria processes. The biomass production cost was as low as 1.9 €·kg^-1, while the cost for nitrogen removal was 4.3 €·kg N^-1.

A review of the cost and effectiveness of solutions to address plastic pollution

Plastic usage increases year by year, and the growing trend is projected to continue. However as of 2017, only 9% of the 9 billion tons of plastic ever produced had been recycled leaving large amounts of plastics to contaminate the environment, resulting in important negative health and economic impacts. Curbing this trend is a major challenge that requires urgent and multifaceted action. Based on scientific and gray literature mainly published during the last 10 years, this review summarizes key solutions currently in use globally that have the potential to address at scale the plastic and microplastic contaminations from source to sea. They include technologies to control plastics in solid wastes (i.e. mechanical and chemical plastic recycling or incineration), in-stream (i.e. booms and clean-up boats, trash racks, and sea bins), and microplastics (i.e. stormwater, municipal wastewater and drinking water treatment), as well as general policy measures (i.e. measures to support the informal sector, bans, enforcement of levies, voluntary measures, extended producer responsibility, measures to enhance recycling and guidelines, standards and protocols to guide activities and interventions) to reduce use, reuse, and recycle plastics and microplastics in support of the technological options. The review discusses the effectiveness, capital expenditure, and operation and maintenance costs of the different technologies, the cost of implementation of policy measures, and the suitability of each solution under various conditions. This guidance is expected to help policymakers and practitioners address, in a sustainable and cost-efficient way, the plastic and microplastic management problem using technologies and policy instruments suitable in their local context.

Wastewater Treatment Using Constructed Wetland: Current Trends and Future Potential

Constructed wetlands (CW) is an environmentally friendly technique for removing pollutants from wastewater and has been applied to municipal wastewater, petroleum refinery wastewater, agriculture drainage, acid mine drainage, etc. The past decade has seen a remarkable number of innovations in the exponentially growing field of microbiology. This manuscript covers a critical review of key aspects of CW, such as various types of CW, the contaminants and their removal mechanisms, degradation pathways, challenges and opportunities, materials, applications, and theory with a focus on recent advances in the last three decades. In addition, an attempt has been taken to project future advances in the field of CW and facilitate these advances by framing key unsolved problems in CW. Guidelines are prepared for the fast-growing CW field through the standardization of key design aspects. This review covers the evaluation of the current state-of-the-art of CW technology and provides definitions and performance metric nomenclature in an effort to unify the fast-growing CW community. It also contains an outlook on the emerging trends in CW and proposes future research and development directions.

Comparative evaluation of cost for preliminary and tertiary municipal wastewater treatment plants in Istanbul

As the global economy continues to grow, the need for an economic evaluation of wastewater treatment plants (WWTPs) is increasing. Determination of cost functions (CFs) helps to assess the costs of WWTP and to be able to reach to the satisfactory financial levels of construction and operation practices in the early phases of a project. In this study, unit capital and operation and maintenance (O&M) costs were calculated by analyzing the real capital and operation and maintenance expenditures of 16 full-scale WWTPs in Istanbul. Besides, the impacts of treatment level and capacity on costs were investigated. The unit total capital cost was found as 0.013 ± 0.004 €/m³ and 0.054 ± 0.009 €/m³ for preliminary and tertiary treatment, respectively, whereas the unit total O&M cost were 0.011 ± 0.007 €/m³ and 0.077 ± 0.021 €/m³ for preliminary and tertiary treatment, respectively. Capital (investment) costs covered 58% of the total cost in preliminary WWTPs, whereas; O&M costs had the highest share (58%) in tertiary WWTPs. The results of this study confirmed that the level of treatment considerably affected the costs of WWTPs. Moreover, the CFs were separately derived for tertiary treatment including A²O with and without digester. The CFs obtained in this study are of utmost importance to be used in the economic evaluation of the planned WWTPs and in the management of existing ones.

The Financing of Wastewater Treatment and the Balance of Payments for Water Services: Evidence from Municipalities in the Region of Valencia

Pollution from wastewater discharges requires the treatment of all wastewater to maintain water bodies in good condition, as well as the possibility of reusing this water. Thus, wastewater treatment is an activity that has developed significantly in the Region of Valencia and has significant costs, including energy, which represents the main economic cost and an important environmental cost. In this way, efficiency and adequate financing of this activity are essential to minimise our environmental impact. However, the main funding tool currently does not allow us to address this issue, so we have a wastewater treatment with a high environmental cost in the form of greenhouse gas emissions. This tool is part of the revenues of water services, so it is not entirely independent, but it also seeks to prevent households from paying too high a total price. This leads to a situation where changes are needed to improve the financing of the different water services, as the financial resources obtained are insufficient and do not allow the current environmental problems to be solved. The analysis shows the importance of an appropriate tariff structure, as well as the need to include aspects such as water pollution and energy costs in the wastewater treatment tariff.

Wastewater Treatment Costs: A Research Overview through Bibliometric Analysis

Given the problem of water scarcity and the importance of this resource for the sustainability of the planet, wastewater treatment and its costs have become a key issue for proper water management. Using bibliometric analysis of publications in the Web of Science database, this study presents an overview of the research on wastewater treatment costs in the period 1950–2020. The worldwide search returned 22,788 articles for wastewater treatment costs, which compares poorly to the results for research on wastewater treatment, accounting for only 12.34% of the total output on wastewater treatment. The findings of this study reveal the leading countries in this field of research (China, USA, India, Spain and the UK), with the articles being published in a wide range of high impact journals. Similarly, there are very few results on UV and chlorination costs, despite the importance of these two treatments for wastewater disinfection and reuse. This study is aimed at researchers in this field, helping them to identify recent trends, and at the main institutions in the scientific community working on this subject.