A Long-Term Follow-Up Study of Slash Bundling in Fast-Growing Eucalypt Plantations

The Authors conducted a long-term follow-up study of a John Deere 1490 forwarder-mounted bundler owned by a Portuguese company and used for bundling logging residues from fast-growing eucalypt plantations located in Portugal and Spain. The study spanned 7 years, from 2011 to 2016. During this time, the machine clocked over 11,500 h and produced more than 200,000 bundles or 75,000 green tons of biomass. Bundle length was commonly 2.4 m, and bundle mass averaged 350 kg. Overall, the database contained 1752 daily records. Bundling productivity averaged 19 bundles per productive machine hour (meter hour, excluding all major delays). Mechanical availability was very high and averaged 93%. Utilization commonly ranged between 65% and 75%. Use and productivity showed a predictable seasonal trend and a slight decline over time. The latter might be due to wear, but also due to the increasingly challenging conditions faced by the company as the average worksite size sharply decreased from 2011 onwards. While almost extinct elsewhere, bundling seems to thrive in the Iberian plantations, possibly due to the industrial character of both eucalypt farming and bioenergy generation in the region. That allows the reaping of all integration benefits offered by bundling, while the cost of setting up a parallel biomass chain is minimized. Furthermore, bundling seems the ideal technique for efficient residue recovery where slash yields are low and roadside storage space is limited: these are the typical constraints of industrial eucalypt plantations, where planted area is maximized (=little landing space) and the largest possible proportion of the tree mass is turned into pulpwood (=relatively low residue yield).

The physico-chemical characteristics of fresh and old pig dungs collected from three pig farmsin Port Harcourt Metropolis

The need to source for alternative use of pigs dung to reduce environmental challenges arising from its application as farm manure prompted the study into the physico-chemical attributes of both the fresh and old pig dung in three pig farms(A,R,U) in Port-Harcourt metropolis. The study examined the pH levels, exchangeable nitrate, extractable phosphate, the total organic carbon and the sulphate using methods described by the pH meter, APHA-4500-O3-B, ASTM D515, Walkley black and ASTM D516 respectively. The results indicated that the dung were alkaline ranging from pH 9-12, the nitrate content was high in fresh dung (16.03-19.40) but considerably low in the dry dung (2.36-2.92), the phosphate values were between 7.59-20.81, the sulphate level falls within 1.84-3.79 whereas the total organic carbon were between 2.36-2.92. The result obtained have showed that the fresh dung could be supplemented with other organic substrate to initiate bioremediation of crude oil polluted soil due to its high nitrate content and the dry dung used as feedstuffs for animal nutrients or feedstock for bioenergy generation because of its high fibre content which will help in reducing the ecosystem contamination by pig waste through recycling.

Sustainable Syntheses and Sources of Nanomaterials for Microbial Fuel/Electrolysis Cell Applications: An Overview of Recent Progress

The use of microbial fuel cells (MFCs) is quickly spreading in the fields of bioenergy generation and wastewater treatment, as well as in the biosynthesis of valuable compounds for microbial electrolysis cells (MECs). MFCs and MECs have not been able to penetrate the market as economic feasibility is lost when their performances are boosted by nanomaterials. The nanoparticles used to realize or decorate the components (electrodes or the membrane) have expensive processing, purification, and raw resource costs. In recent decades, many studies have approached the problem of finding green synthesis routes and cheap sources for the most common nanoparticles employed in MFCs and MECs. These nanoparticles are essentially made of carbon, noble metals, and non-noble metals, together with a few other few doping elements. In this review, the most recent findings regarding the sustainable preparation of nanoparticles, in terms of syntheses and sources, are collected, commented, and proposed for applications in MFC and MEC devices. The use of naturally occurring, recycled, and alternative raw materials for nanoparticle synthesis is showcased in detail here. Several examples of how these naturally derived or sustainable nanoparticles have been employed in microbial devices are also examined. The results demonstrate that this approach is valuable and could represent a solid alternative to the expensive use of commercial nanoparticles.

Assessing the Cost of Biomass and Bioenergy Production in Agroindustrial Processes

This paper presents bioenergy value chain modelling to estimate the biomass and bioenergy cost of production and biomass netback in combined heat and power (CHP) systems. Modelling compares biomass cost and netback to analyse the feasibility of CHP systems, as well as the internal rate of return (IRR) and payback period (PBP). Models are implemented into the IMP Bio2Energy® software (Instituto Mexicano del Petróleo, Mexico City, Mexico) for practical application and demonstrated for bioenergy generation in the agroindustrial processes of tequila production, coffee and orange processing using as biomass the agave bagasse, coffee pulp and orange peels coproducts, respectively. Results show that the CHP systems are economically feasible, i.e., biomass cost of production is lower than netback, PBP between 3 and 4 years and IRR > 20%. The cost of bioenergy is lower than the cost of fuel oil and grid electricity being replaced. The sensitivity analysis for boiler steam pressure showed that there is an optimal pressure for coffee pulp (40 bar), a threshold pressure for orange (60 bar) and agave bagasse (70 bar). Sensitivity to biomass input indicated a maximum capacity where economy of scale does not produce any improvement in the indicators. Results demonstrate the usefulness of the modelling approach and IMP Bio2Energy® in analysing biomass CHP systems.

A Mini-Review on Applications of 3D Printing for Microbial Electrochemical Technologies

For the past two decades, many successful applications of microbial electrochemical technologies (METs), such as bioenergy generation, environmental monitoring, resource recovery, and platform chemicals production, have been demonstrated. Despite these tremendous potentials, the scaling-up and commercialization of METs are still quite challenging. Depending on target applications, common challenges may include expensive and tedious fabrication processes, prolonged start-up times, complex design requirements and their scalability for large-scale systems. Incorporating the three-dimensional printing (3DP) technologies have recently emerged as an effective and highly promising method for fabricating METs to demonstrate power generation and biosensing at the bench scale. Notably, low-cost and rapid fabrication of complex and miniaturized designs of METs was achieved, which is not feasible using the traditional methods. Utilizing 3DP showed tremendous potentials to aid the optimization of functional large-scale METs, which are essential for scaling-up purposes. Moreover, 3D-printed bioanode could provide rapid start-up in the current generation from METs without any time lags. Despite numerous review articles published on different scientific and applied aspects of METs, as per the authors’ knowledge, no published review articles explicitly highlighted the applicability and potential of 3DP for developing METs. Hence, this review targets to provide a current overview and status of 3DP applications for advancing METs and their future outlook.