Search results for " wastewater"

Integrated production of biopolymers with industrial wastewater treatment: Effects of OLR on process yields, biopolymers characteristics and mixed mi…

2022

The production of polyhydroxyalkanoates (PHA) using industrial wastewaters as feedstocks is a current and challenging topic. This study investigated the production of biopolymers by a mixed microbial culture under different OLRs equal to 1 kgCOD m-3d-1 (Period 1), 2 kgCOD m-3d-1 (Period 2) and 3 kgCOD m-3d-1 (Period 3). The maximum PHA content was achieved in Period 2 (0.38 gPHA gTSS-1), whereas lower values were obtained in Period 1 (0.13 gPHA gTSS-1) and Period 3 (0.26 gPHA gTSS-1). Overall, the maximum PHA productivity resulted equal to 0.08 gPHA L-1h-1 (P2), 0.05 gPHA L-1h-1 (P1) and 0.04 gPHA L-1h-1 (P3), respectively. The molecular weight of the PHA increased from Period 1 (250 kDa) t…

Characterization of wastewater and biomass activity in a membrane bioreactor using respirometric techniques

2010

Over the last two decades, Membrane Bioreactors (MBRs) emerged even more for wastewater treatment, ensuring high removal efficiencies as well as very small footprint required. Indeed, in this kind of process, a modification in biomass activity and viability can exist compared to that of a conventional activated sludge (CAS) process. In this context, respirometric analysis represents a reliable tool in order to evaluate the actual biomass kinetic parameters, to insert in mathematical models in the design phase, as well as to monitor the biomass viability, especially when these processes are operated with high sludge retention time (SRT) values. The paper presents some results of respirometri…

Wastewater treatment sludge composting

2023

In recent years, the amount of sewage sludge generated by wastewater treatment plants (WWTPs) has increased due to worldwide population growth and to efficiency of biological treatment processes [1,2]. Sludge is an important source of secondary pollution to aquatic environments and a potential risk to human health; moreover, it represents one of the most important cost items in the functioning of water treatment plants [3–5]. About 60% of the operating costs of secondary wastewater treatment plants in Europe can be associated with the treatment and disposal of products [6]. For this reason, proper sludge management becomes increasingly important, at both national and international level, an…

Dewatering of excess sludge produced by CAS and MBR aerobic treatment plants. effects of biochemical stability and EPS composition

2016

This paper investigates the behavior of different sludges from several treatment plants at full and pilot scale configured as Conventional Activated Sludge (CAS) and Membrane Bio Reactor (MBR) plants treating different kinds of wastewaters. The sludges collected were subjected to complete analytical and technological characterization in order to correlate the rheological properties that affect the dewatering behavior to the sludge chemical physical properties. In detail the EPS from the samples collected is extracted and characterized in terms of carbohydrates, proteins, uronic acids and humic acids content. Moreover, once characterized, the sludges were subjected to AD in order to assess t…

II ADVANCED COURSE Innovative wastewater treatment and mathematical modeling

2017

Over the past years, the knowledge and understanding of biological wastewater treatment has advanced extensively and moved away from empirically-based approaches to a fundamentally-based 'first principles' approach that embrace: bio-chemistry, microbiology, mathematics, and physical, chemical and bioprocess engineering. Also, the wastewater treatment plant of the future will be a water resource recovery facility (WRRF), implying attention for quite different aspects of these large scale technologies. Many of these advances have matured to a degree that they have been codified into mathematical models able to describe and simulate diverse systems under different environmental conditions at e…

Combined membrane and thermal desalination processes for the treatment of ion exchange resins spent brine

2019

Abstract The disposal of industrial wastewater effluents represents a critical environmental issue. This work focuses on the treatment of the spent brine produced by the regeneration of ion exchange resins employed for water softening. For the first time, a comprehensive techno-economic assessment and an analysis of the energy requirements of the treatment chain are carried out, via the simulation of ad hoc implemented models. The chain is composed of nanofiltration, double-stage crystallization and multi-effect distillation. The valuable product is the brine produced by the multi-effect distillation, which can be re-used for the regeneration. Therefore, the treatment chain’s economic feasi…

Towards the implementation of circular economy in the water softening industry: A technical, economic and environmental analysis

2020

Abstract To reduce the environmental impact of the industrial sectors, circular strategies should be implemented to purify the effluents and recover raw materials. In this context, a novel integrated methodological approach is proposed to identify the most suitable strategy to improve the sustainability of the water softening industry via the treatment and recycling of the produced wastewater. Different concentration technologies and energy supply systems are compared to find economically feasible and environmentally friendly treatment systems. The investigated chains present the same pre-treatment step (nanofiltration and crystallization) and different concentration technologies: Multi-Eff…

Application of diffusion dialysis in separation of sulfuric acid and copper from electroplating wastewater

Electroplating industry creates large volumes of wastewater that contain acids and heavy metallic ions which are toxic but valuable. Diffusion dialysis (DD) can be used to separate acids from heavy metals. In this work, two single-cell DD modules equipped with Fumasep FAD membranes were used for the first time for the separation of sulfuric acid from copper. The first module consisted of a laboratory-scale DD unit operated in a batch configuration to study the effect of process parameters on the efficiency of sulfuric acid recovery. The latter one was a large-scale DD unit operated in a continuous configuration to simulate the process operation at the industrial scale. Results showed that F…

An integrated approach for the HCl and metals recovery from waste pickling solutions: pilot plant and design operations

2021

Abstract Continuous regeneration of industrial pickling solutions and recovery of valuable materials are implemented in a pilot-scale plant including diffusion dialysis (DD), where HCl is recovered, membrane distillation (MD), where HCl is concentrated, and reactive precipitation (CSTR), where metal ions are recovered in different forms. The integration of the three processes allows to minimize waste streams generation and to accomplish a closed-loop process, thus increasing the environmental sustainability and economic impact of the galvanizing industry. Process reliability was proved through the operation of a demonstrator in the real industrial environment of the Tecnozinco SrL hot-dip g…

Design of a novel membrane-integrated waste acid recovery process from pickling solution

2019

Abstract Hydrochloric acid pickling is a common practice in steel manufacturing industry. During the process, acid is consumed to dissolve surface oxides and metals ions are accumulated in the solution, which becomes less effective with time. In addition, the costly and risky waste acid disposal is another issue affecting the hot-dip galvanizing industry. In this work, a novel sustainable waste acid recovery process from pickling solutions based on circular approach is proposed to tackle these issues. The innovative system allows (i) the continuous regeneration of pickling solutions to enhance process rate and performance and (ii) minimise the highly expensive and environmentally risky wast…