scholarly journals Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4752
Author(s):  
Agnieszka Urbanowska ◽  
Małgorzata Kabsch-Korbutowicz ◽  
Christian Aragon-Briceño ◽  
Mateusz Wnukowski ◽  
Artur Pożarlik ◽  
...  

New regulations aimed at curbing the problem of eutrophication introduce limitations for traditional ways to use the by-product of anaerobic digestion—the digestate. Hydrothermal carbonisation (HTC) can be a viable way to valorise the digestate in an energy-efficient manner and at the same time maximise the synergy in terms of recovery of water, nutrients, followed by more efficient use of the remaining carbon. Additionally, hydrothermal treatment is a feasible way to recirculate recalcitrant process residues. Recirculation to anaerobic digestion enables recovery of a significant part of chemical energy lost in HTC by organics dissolved in the liquid effluent. Recirculating back to the HTC process can enhance nutrient recovery by making process water more acidic. However, such an effect of synergy can be exploited to its full extent only when viable separation techniques are applied to separate organic by-products of HTC and water. The results presented in this study show that using cascade membrane systems (microfiltration (MF) → ultrafiltration (UF) → nanofiltration (NF)), using polymeric membranes, can facilitate such separation. The best results were obtained by conducting sequential treatment of the liquid by-product of HTC in the following membrane sequence: MF 0.2 µm → UF PES 10 → NF NPO30P, which allowed reaching COD removal efficiency of almost 60%.

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2431
Author(s):  
Roberto Murano ◽  
Natascia Maisano ◽  
Roberta Selvaggi ◽  
Gioacchino Pappalardo ◽  
Biagio Pecorino

Nowadays, most Italian biogas produces electricity even though recent political incentives are promoting biomethane from biogas by “upgrading” it. The aim of this paper is to focus on the regulatory framework for producing biomethane from new or already-existent anaerobic digestion plants. The complexity and lack of knowledge of the regulations on biofuel production and of anaerobic digested biomethane from waste and by-products create difficulties of both interpretation and application. Consequently, the aim of this paper is to analyze the regulations for producing biomethane, underline the critical issues and opportunities, and evaluate whether an electrical plant built in the last 10 years in Italy can really be converted to a biomethane plant, thereby lengthening its lifespan. Three case studies were considered to look more closely into applying Italian biomethane incentives and to simulate the types of incentivization in agriculture with examples based on certain fuel types typical of a standard biomethane plant of 500 standard cubic meter per hour. All the considered cases put in evidence that biomethane is a further opportunity for development with a high level of efficiency for all biogas producers, especially for many biogas plants whose incentivization period is about to finish.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5983
Author(s):  
Aaron E. Brown ◽  
Jessica M. M. Adams ◽  
Oliver R. Grasham ◽  
Miller Alonso Camargo-Valero ◽  
Andrew B. Ross

Water hyacinth (WH) is an invasive aquatic macrophyte that dominates freshwater bodies across the world. However, due to its rapid growth rate and wide-spread global presence, WH could offer great potential as a biomass feedstock, including for bioenergy generation. This study compares different integration strategies of hydrothermal carbonisation (HTC) and anaerobic digestion (AD) using WH, across a range of temperatures. These include (i) hydrochar combustion and process water digestion, (ii) hydrochar digestion, (iii) slurry digestion. HTC reactions were conducted at 150 °C, 200 °C, and 250 °C. Separation of hydrochars for combustion and process waters for digestion offers the most energetically-feasible valorisation route. However, hydrochars produced from WH display slagging and fouling tendencies; limiting their use in large-scale combustion. AD of WH slurry produced at 150 °C appears to be energetically-feasible and has the potential to also be a viable integration strategy between HTC and AD, using WH.


2021 ◽  
Vol 58 (02) ◽  
pp. 192-203
Author(s):  
Padam Singh ◽  
T. P. Singh ◽  
Rajat Kumar Sharma ◽  
Yogesh Kumar Negi ◽  
Ramesh Pal

Pine needle is a typical biomass which is abundantly available in Uttarakhand hills. This shredded biomass contributes significantly in forest fire occurring regularly in Uttarakhand. Different energy harnessing routes as direct combustion, anaerobic digestion, pyrolysis, gasification, and briquetting for pine needle were reviewed. These routes were further compared on the basis of energy consumption and energy efficiency of the processes as per the available literature. The review suggested that briquetting of pine needle and its anaerobic digestion are two most energy efficient methods having energy efficiency of 88% and 41.6%, respectively. The estimated energy required for briquetting of 1 ton pine needle was 1370.5 MJ, whereas for gasification it was 1170 MJ


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2415
Author(s):  
Taegyun Kwon ◽  
Jinyoung Chun

Although water, air, and other resources are abundant on earth, they have been subjected to strict environmental regulations. This is because of their limitation of availability for human consumption. In the separation industry, the membrane system was introduced to increase the amount of resources available to mankind. Experts used an easy-to-use polymeric material to design several membranes with porous structures for wastewater treatment, gas separation, and chemical removal; consequently, they succeeded in obtaining positive results. However, past polymeric membranes exhibited a chronic drawback such that it was difficult to simultaneously augment the permeate flux and improve its selectivity toward certain substances. Because of the trade-off relationship that existed between permeability and selectivity, the membrane efficiency was not very good; consequently, the cost-effectiveness was significantly hindered because there was no other alternative than to replace the membrane in order to maintain its initial characteristics steadily. This review begins with the introduction of a polymer nanocomposite (PNC) membrane that has been designed to solve the chronic problem of polymeric membranes; subsequently, the stimuli-responsive PNC membrane is elucidated, which has established itself as a popular topic among researchers in the separation industry for several decades. Furthermore, we have listed the different types and examples of stimuli-responsive PNC membranes, which can be switched by external stimuli, while discussing the future direction of the membrane separation industry.


2019 ◽  
Vol 29 (09) ◽  
pp. 2050141 ◽  
Author(s):  
Muhammed Enes Bayrakdar

In this paper, a monitoring technique based on the wireless sensor network is investigated. The sensor nodes used for monitoring are developed in a simulation environment. Accordingly, the structure and workflow of wireless sensor network nodes are designed. Time-division multiple access (TDMA) protocol has been chosen as the medium access technique to ensure that the designed technique operates in an energy-efficient manner and packet collisions are not experienced. Fading channels, i.e., no interference, Ricean and Rayleigh, are taken into consideration. Energy consumption is decreased with the help of ad-hoc communication of sensor nodes. Throughput performance for different wireless fading channels and energy consumption are evaluated. The simulation results show that the sensor network can quickly collect medium information and transmit data to the processing center in real time. Besides, the proposed technique suggests the usefulness of wireless sensor networks in the terrestrial areas.


2009 ◽  
Vol 33 (8) ◽  
pp. 1046-1054 ◽  
Author(s):  
Anette Hejnfelt ◽  
Irini Angelidaki

2020 ◽  
Vol 34 (18) ◽  
pp. 2050203
Author(s):  
Supreet Kaur ◽  
Vijay Kumar Joshi

A hybrid protocol is proposed which utilizes secure clustering and hybrid soft computing to improve the network lifetime. Ant colony optimization (ACO) and Particle swam optimization (PSO) with crossover operator are used to design a hybrid soft computing-based inter-cluster data aggregation. Initially, cluster heads are selected based upon adaptive threshold function. Recommendation-based signatures are then assigned to every aggregated data. Then, tree-based data aggregation comes in action and collects sensing information directly from cluster heads by utilizing short distance obtained from the hybrid soft computing. The use of compressive sensing reduces the packet size which is going to be transmitted in the sensor network. Extensive analysis shows that the hybrid protocol considerably enhances network lifetime by conserving the energy in more efficient manner than other protocols at present deployed for sensor networks.


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