Valorization of ß-Chitin Extraction Byproduct from Cuttlefish Bone and Its Application in Food Wastewater Treatment.

The nontoxicity, worldwide availability and low production cost of cuttlefish bone products qualify them an excellent biocoagulant to treat food industry wastewater. In this study, cuttlefish bone liquid waste from the deproteinization step was used as a biocoagulant to treat food industry wastewater. This work concerns a waste that has never before been investigated. The objectives of this work were: the recovery of waste resulting from cuttlefish bone deproteinization, the replacementof chemical coagulants with natural ones to preserve the environment, and the enhancement ofthe value of fishery byproducts. A quantitative characterization of the industrial effluents of a Moroccan food processing plant was performed. The physicochemical properties of the raw cuttlefish bone powder and the deproteinization liquid extract were determined using specific analysis techniques: SEM/EDX, FTIR, XRD and 1H-NMR. The protein content of the deproteinization liquid was determined by OPA fluorescent assay. The zeta potential of the liquid extract was also determined. The obtained analytical results showed that the deproteinization liquid waste contained an adequate amount of soluble chitin fractions that could be used in food wastewater treatment. The effects of the coagulant dose and pH on the food industrial effluents were studied to confirm the effectiveness of the deproteinization liquid extract. Under optimal conditions, the coagulant showed satisfactory results. Process optimization was performed using the Box-Behnken design and response surface methodology. Thus, the optimal removal efficiencies predicted using this model for turbidity (99.68%), BOD5 (97.76%), and COD (82.92%) were obtained at a dosage of 8 mL biocoagulant in 0.5 L of food processing wastewater at an alkaline pH of 11.

Environmental and economic analysis of bioethanol production from sugarcane molasses and agave juice.

In this article, sugarcane molasses and agave juice were compared as potential feedstocks for producing bioethanol in Mexico in terms of their environmental impact and economic factors. Life cycle assessment (LCA) using SimaPro was carried out to calculate environmental impacts by using a cradle-to-gate approach. A preliminary economic analysis was performed to determine the economic feasibility of the studied options. Also, capital goods costs were obtained using the Aspen Plus economy package. Moreover, a sensitivity analysis was involved to compare the environmental and economic viability of producing bioethanol from sugarcane molasses and agave juice. LCA results revealed that cultivation and fermentation were the most harmful stages when producing bioethanol from sugarcane molasses and agave juice, respectively. Furthermore, when it was derived from agave juice rather than sugarcane molasses, it had more environmental benefits. This was ascribed to the lower consumption rate of fertilizers, pesticides, and emissions given off from the former. Regarding financial aspects, the preliminary analysis showed that producing bioethanol was not economically viable when grid energy alone was used. However, if power from the grid is partially replaced with renewable energy, producing bioethanol becomes economically feasible, and sugarcane molasses is the most suitable feedstock.

Investigation of a biosystem based on Arthrospira platensis for air revitalisation in spacecrafts: Performance evaluation through response surface methodology.

Arthrospira platensis is featured as a promising microalgae candidate for the development of the biosystems for air revitalisation in spacecrafts and life support in space. An enhanced configuration of a sparged type photobioreactor (PBR), containing 5 L of A. platensis culture, which was equipped with an external LED lighting tube around the reactor, was used in this study. The PBR was operated under dynamic conditions (0.5 L/min) with synthetic air containing CO2 (400, 900, 1400 ppm) and other gas traces (NO2 1 ppm, SO2 2.5 ppm, acetic acid vapours 1 ppm), at various light intensities (1.5, 2.5, 3.5 klux), according to an experimental design. The removal of gas traces (NO2, SO2 and acetic acid vapours) was below the detection limit (e.g. above 90% removal efficiency), while the removal of CO2 ranged between 69% and 85%, depending on the initial CO2 concentration and the light intensity. Thus, the system is able to roughly decrease the contaminant concentration from 1 ppm to below 0.1 ppm for NO2, 2.5 ppm to below 0.1 ppm for SO2, 1 ppm to below 1 ppb for acetic acid vapours and from 1400 ppm to 370 or from 400 ppm to 60 ppm for CO2. The system performance was thus subject to mathematical modelling and optimization in terms of CO2 removal efficiency and CO2 elimination capacity, which were also corroborated with the power consumption for illumination.

Insights into siloxane removal from biogas in biotrickling filters via process mapping-based analysis.

Data process mapping using response surface methodology (RSM)-based computational techniques is performed in this study for the diagnosis of a laboratory-scale biotrickling filter applied for siloxane (i.e. octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5)) removal from biogas. A mathematical model describing the process performance (i.e. Si removal efficiency, %) was obtained as a function of key operating parameters (e.g biogas flowrate, D4 and D5 concentration). The contour plots and the response surfaces generated for the obtained objective function indicate a minimization trend in siloxane removal performance, however a maximum performance of approximately 60% Si removal efficiency was recorded. Analysis of the process mapping results provides indicators of improvement to biological system performance.

Empirical modelling and dual-performance optimisation of a hydrogen sulphide removal process for biogas treatment.

This study was conducted in order to investigate the use of a simple, low-cost technology for the removal of hydrogen sulphide (H(2)S) from biogas, consisting of an anoxic biotrickling filter. Modelling and optimisation of the process was achieved by studying two independent variables (H(2)S concentration and biogas flowrate) and two simultaneous performance criteria (H(2)S removal efficiency (%) and H(2)S loading rate (g/(m(3) bed day)), which were inversely related. The experiments were carried out on a bioreactor with a 12 L packing volume. H(2)S concentration and biogas flowrate were varied in the range of 2000-4000 ppm(v) and 10-70 L/h, respectively. A model sensitivity analysis indicated the influence of the process variables on the bioreactor performance. Process optimisation was undertaken on a H(2)S removal efficiency basis, while maintaining a target H(2)S loading rate, depending on the desired quality for the biogas use and the technological requirements.

Evaluation of different packing media for anoxic H2S control in biogas.

This paper presents the experimental results obtained during the operation of two biotrickling filters packed with 6.7 L of commercially available plastic fibres and lava rocks, respectively. The biotrickling filters were tested under similar operating conditions for hydrogen sulphide (H2S) removal from biogas under anoxic conditions, in order to determine the influence of biogas flow rate and H2S concentration on the process performance and to facilitate process modelling. The biogas flow rate was adjusted to between 25 and 75 L/h, while the input H2S concentration was varied between 500 and 1500 ppmv. The process performance was evaluated by two simultaneous system responses, namely the H2S removal efficiency and H2S loading rate, which were subsequently described by a second-order empirical model and an interaction model, respectively. Good agreement between the experimental results, model prediction and simultaneous dual-response simulation was obtained.