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Many organic residues are being wasted since they are not given a comprehensive management; anaerobic digestion is an alternative to reduce the impact of these residues, and to produce biogas. The chapter includes the state of art about biogas and energy production, and later, the analysis of a study case focusing on the use of pulp and paper wastes to produce biogas. The study was carried out through anaerobic digestion at a bench scale using three temperature phases to treat primary and secondary sludge, establishing operational parameters such as temperature, retention time, and organic loadings. Monitoring of volume, methane concentration in the biogas, volatile solids reduction, volatile fatty acids during the process, the performance of the process in function of methane produced per volatile solids removed is calculated. This case study shows that it is feasible to use the sludge from the company’s wastewater treatment plant (WWTP) for the generation of biogas, thus reducing waste management problems.

This study focused on determining the optimal conditions for lead removal in aqueous solution models, by the spherical agglomeration technique (SAT), modifying the dose of Agave lechuguilla Torr. (lechuguilla) extract, used as biosurfactant. The SAT operating conditions at room temperature were: Initial pH 9, and constant agitation ω = 600 rpm. Experiments were performed under a 5x3 factorial design with five lechuguilla extract doses (0.3 - 2.0 g extract/g of pollutant), three different lead concentrations (1, 5 and 10 mg/L) and, for the SAT last stage, two different dosage ratio of CaCl2 (10:1 and 20:1 parts of Ca2+ by part of pollutant). Residual lead, sodium and calcium were determined by atomic absorption spectroscopy. According to statistical analysis, significant effects were observed for calcium dosages, initial lead concentration, extract dose and their interaction. The lead removal efficiency obtained by SAT reached 99.8%.

Effluent found in the pulp and paper industry can cause considerable damage if it is discharged untreated, because of the high biochemical and chemical oxygen demands. Electrocoagulation is a physicochemical process widely used in industrial wastewater treatment. The removal of different pollutants depends on the sample type and operating conditions. The aim of this research was to evaluate the efficiency of an electrocoagulation system for COD removal from recycled paper production effluent via aluminum and iron electrodes. Different operational parameters, such as the electrolysis time (5 min to 15 min), current density (7 A/m2 to 11 A/m2), and distance between each electrode (5 mm to 20 mm), were evaluated. The turbidity, total suspended solids, chlorides, sulfates, and COD had removal efficiencies of 92.7%, 91.3%, 70.4%, 66.6%, and 64%, respectively. A polynomial model was generated to estimate the optimum conditions for COD removal. The optimum times for the current densities 7 A/m2, 8 A/m2, 9 A/m2, 10 A/m2, and 11 A/m2 were 39.5 min, 39.5 min, 35.7 min, 34.1 min, and 32.8 min, respectively, with a 15-mm electrode gap.

The search for microbial enzymatic activities applied to wastewater treatment is an important task in environmental biotechnology. Microbial enzymes have been previously explored in hostile habitats. They are increasingly important in extreme habitats; biological wastewater from the pulp and paper mill industry can harbor microorganisms with valuable enzymatic capabilities that can improve the efficiency for the same process of depuration. This study was performed to characterize and evaluate cellulolytic, amylolytic, and lipolytic activities of bacteria isolated from a pulp and paper effluent. The enzymatic activities were evaluated by the formation of a clear halo around the colonies in defined substrate media. By the use of a sequence analysis of 16S rDNA libraries, isolates were identified. The 16S rDNA libraries belong to the Bacillus subtilis, B. megaterium, B. licheniformis, B. pumilus, B. thuringiensis, B. cereus, Chryseobacterium daecheongense, and Microbacterium sediminis (an alkali-tolerant bacteria which has only been isolated from deep-sea sediment). B. cereus was the best strain for cellulose and lipase activities; moreover, C. daecheongense was best for amylase activity. The present study shows that the aerated lagoons from the pulp and paper industry are a promising source of bacterial with different enzyme activities. This data is relevant for industrial applications.

Effluents form the swine livestock industry contain a high concentration of pollutants and require complex treatment systems. The most recurrent form to treat Swine wastewater is by a conventional anaerobic–aerobic treatment. For example, an up-flow anaerobic blanket sludge reactor followed by an activated sludge reactor. However, in many countries, a high percentage of producers are small or medium-sized farms that can afford neither complex treatment systems nor specialized operations. The present study assessed the performance of a novel and different combinations of treatment processes, based on changing the anaerobic systems that require a specialized operation for one very simple to operate for farm owners. The assessed system is composed by a septic tank in combination with an up-flow anaerobic filter packed with volcanic rocks and an aerobic biofilter packed with waste wood chips. The effect of the hydraulic residence time and the volumetric organic loading in the septic tank and up-flow anaerobic filter and the effect of surface hydraulic loading in the aerobic biofilter were also evaluated. The system efficiently removed chemical oxygen demand (86–93%), total suspended solids (91–97%), volatile suspended solids (86–97%), and ammoniacal nitrogen (86–87%), showing a constant removal efficiency under a VOL of between 5 and 14.6 kg COD m−3 d−1in the up-flow anaerobic filter. The advantages of this system are that the packing materials can be available in rural zones and are sustainable; the whole system is cost-effective and easy to handle; thus, farmers can operate and maintain it with their own means.

Tea contains health benefits due to its compounds such as catechins, which undergo thermolysis during heating. These complex reactions have been proposed as first order kinetic models at controlled conditions, and this work proposes a non‐first‐order kinetic model to cover a wide range of conditions. Afterward, these reactions were simulated via computational fluid dynamics in order to determine the concentration at different operative conditions. The system was a continuous heating reactor, where mesh and iteration tests were developed. The results indicated that the reactions presented a high thermal dependency, and a short residence time with low conversion due to the low values of the Damkohler number. Thus, the kinetic model proposed herein reached a well representation of the thermolysis of catechins, which suggests the applicability of this model and strategy in other thermal treatments of tea. PRACTICAL APPLICATION: The high comsumption of green tea demands better process treatments in order to reduce the perishable compounds. Thermal processing of tea requires a thorough understanding of thermolysis in catechins. The basis of this paper can be extended into evaporation and drying of green tea under CFD simulation.

Flavor and aroma molecules (FAMs) are high-value compounds used as safe additives to increase the sensorial properties of product formulations. Natural production of these compounds is preferred by consumers; hence, several strategies for this have been developed over time, including the use of biological systems such as bacteria, fungus, and yeast. However, most of these microorganisms are inhibited by the substrate or the product, limiting production. Continued development in bioreactor design to overcome these limitations has been reported, especially in the use of partitioning bioreactors. The concept of partitioning bioreactors presents great potential for improving the productivity of several bioprocesses. The proper selection of the dispersed phase is the key to the successful application of this approach in industrial practice. The integration of the bioprocess and the separation of the product have a positive impact on the productivity of FAMs processes. Controlling the supply of the substrate from the dispersed to the aqueous phase opens a new application for this strategy in the production and bioconversion of FAMs. However, it is necessary for the academic community to continue studying partitioning reactors and the phenomena that occur in such reactors in bioconversion systems used for the production of flavor and aroma molecules.

The pulp and paper mill process requires large amounts of water. Therefore, the need to reuse water through the application of coagulation-flocculation processes, which is effective in the removal of solids and colloidal particles, has risen. In such processes, zeta potential (ZP) provides important information about the efficiency of the reagents used. The purpose of this study was to develop individual and combined tests of reagents to study turbidity and COD reduction based on ZP in the process of wastewater internal treatment for recirculation in the pulp and paper process. Factorial models were developed to explain the behavior of ZP depending on the different coagulants/flocculants. The statistical analyses showed that ZP had a positive correlation with parameters related to removal (COD and turbidity). It was demonstrated that innovate use of lentil extract (Lens esculenta) applied with aluminum sulfate favored the treatment, consistent with a coagulation-flocculation mechanism. The optimum doses of lentil extract were able to reduce the requirements of aluminum sulfate by almost 29%, providing an alternative strategy for water reuse processes in the pulp and paper industry.

Aerated lagoons are a main unit operation for wastewater treatment in the paper industry. Many such operations involve inoculation with bacterial formulations in which in situ effectiveness has not been proven; this can be translated into low efficiency in treatment and unnecessary investments. Lack of knowledge of bacterial biodiversity present in a lagoon limits the capacity to exploit the maximum degradation. To overcome such problems, various methods to identify and study these microorganisms have been developed. In this study, a PCR-DGGE analysis was performed to estimate the bacterial diversity and to verify the presence of bacteria present in a commercial inoculum in two aerated lagoons of a pulp and paper effluent. Phylogenetic affiliation of predominant member’s correspondent to γ- and β-proteobacteria and Firmicutes were found. The dominant bacteria present in lagoon 2 belonged to the following genus Microbacterium sp. Rhodocyclaceae sp., Eubacterium sp. and B. subtilis. In lagoon 1 the dominant genus included Microbacterium sp., Rhodocyclaceae sp. Tepidimonas sp., Acetanaerobacterium sp., and Flavobacteria sp. The two characterized lagoons were not similar to the commercial inoculum. In addition, non-dominant bacteria (less relative intensity) were composed mostly of bacteria of the commercial inoculum.

One of the processes most used in biotechnology today for handling industrial liquid wastes is biological wastewater treatment. The efficiency and quality of its operation depends on the composition and activity of the microbial community that is present. The application of traditional and molecular techniques has provided a glimpse into the “black box” and has given information to improve the wastewater treatment process. However, bleach pulp and paper mill effluents require a better understanding of the active bacterial population. For the study of these microorganisms, molecular techniques have been used for more than 15 years. However, there has been a lack of knowledge of the physiological requirements and relations with the environment, which seems to be very difficult to obtain involving profile on the diversity. Nowadays, high-throughput sequencing technology is a promising method that makes it possible to identify the entire profile of microbial communities. In combination with fingerprint methods, this approach allows the identification and analysis of the whole biodiversity of microbial communities. In this review, several identification techniques will be discussed.

Una revisión (2004-2011) sobre, los procesos biológicos que mayormente se han estudiado para el tratamiento de efluentes porcícolas, demuestra que estos son: digestores anaerobios, reactor anaerobio de flujo ascendente, filtros anaerobios, reactor secuencial en lote, sistemas lagunares y biofiltros. A partir de una comparación entre la forma de operación y de la eficiencia reportada para los diferentes procesos, se concluye que una buena opción de tratamiento podría ser un sistema combinado de filtros sumergidos anaerobios con filtro percolador aireado, ya que los filtros anaerobios requieren un menor tiempo de retención hidráulico para la reducción de la materia orgánica y por otra parte, los biofiltros aerados pueden alcanzar eficiencias de remoción de nitrógeno mayores a las de otros sistemas (lagunas, variantes de lodos activados, etc). Sin embargo, aunque existen algunos estudios sobre el seguimiento de los mecanismos para la remoción de nitrógeno en biofiltros, se requiere realizar estudios adicionales al respecto. Se propone que una posible estrategia sería estudiando el efecto de la relación C/N y de la tasa aireación en estos sistemas de tratamiento

A review (2004-2011) reveals that, the biological processes that have been studied mostly for pig effluent treatment, are: anaerobic digesters, upflow anaerobic sludge reactors, anaerobic filters, secuential batch reactors, lagoon systems and biofilters. From a comparison between the operational characteristics and the pollutants removal efficiency reported for those different processes; it could be concluded that a good treatment option could be a combined system of anaerobic filter submerged followed by an aerated trickling filter; since anaerobic filters require less hydraulic retention time to reduce the organic matter and, moreover, the biofilter can reach nitrogen removal efficiencies greater than those of other systems (lagoons, activated sludge variations, etc). However, although there are some studies on monitoring mechanisms for nitrogen removal in biofilters, it requires further studies in this regard. It is proposed that a possible strategy would be studying the effect of the C/N ratio and the aeration rate in these treatment systems.

Foodstuffs often experience great damage as a result of various forms of infestation or plague. A very common plague is a form of larval infestation that attacks several fruits, including apples. A novel method to identify larval infestations in apples is introduced. This noninvasive method is based on the use of ultrasonic waves, wavelets, and statistical analysis. A wavelet algorithm was preferred over other techniques because it allows a better description of the ultrasonic signal received from the fruit. A total of 998 red delicious apples were sampled, of which, 291 apples were infested by Cydia pomonella. All samples were scanned using ultrasonic waves, and reflecting signals were analyzed with wavelets to determine whether the fruit was intact or infested by larva. The experiments were validated using normality tests and analysis of variance and corroborated by comparing the results with the physical evidence in the specimens. The results show that the signal is attenuated at the center of the apple, which means that the density inside the apple changes as a result of the presence of larva. In addition, the proposed method effectively detected (p < 0.01) the presence of larva within the fruit in real time.

A pilot-scale aerated lagoon was used for the aerobic treatment of pulp and paper mill effluent from September 1 to December 1, 2014. The aerated lagoon was installed at the chemistry laboratory in the Chemical Engineering Department at the Durango Institute of Technology and was fed with real pulp and paper mill effluent. The experimental work was run under various operating conditions. The operating parameters (total and volatile suspended solids (VSS) and dissolved oxygen concentration (DO)) and environmental variables (temperature, pH, COD, and BOD5 of influent water) were monitored daily. In all the experiments conducted, the aerated lagoon generated an effluent of optimal quality complying with the requirements of SEMARNAT (2003) and CONAGUA (2003). A model that explains the behavior of the system under realistic operating conditions was obtained. The model indicated an optimal DO of approximately 4 mg/L for concentrations up to 1000 mg/L, showing variations in concentrations above this value. This data indicate that the flexibility of the bacterial formulation and its ability to adapt to environmental changes play an important role in the stability of an aerated lagoon.

While principal component analysis (PCA) has found wide application in process monitoring, slow and normal process changes often occur in real processes, which lead to false alarms for a fixed-model monitoring approach. In this paper, we propose two recursive PCA algorithms for adaptive process monitoring. The paper starts with an efficient approach to updating the correlation matrix recursively. The algorithms, using rank-one modification and Lanczos tridiagonalization, are then proposed and their computational complexity is compared. The number of principal components and the confidence limits for process monitoring are also determined recursively. A complete adaptive monitoring algorithm that addresses the issues of missing values and outlines is presented. Finally, the proposed algorithms are applied to a rapid thermal annealing process in semiconductor processing for adaptive monitoring.

We benchmark eight different system identification algorithms on an industrial wastewater reactor under both closed loop and open loop conditions. The algorithms studied in the paper include subspace identification, partial least squares, ordinary least squares, and output error approach. The studied model structures include ARX, ARMAX, and FIR models. The minimum description length principle and Akaike information criterion are used to select the order of these models. Comparison of the eight different algorithms are given based on open loop experimental data and closed loop operational data from a real industrial wastewater reactor.

Pulp and paper mills are a major source of pollution, generating huge amounts of intensely colored effluent that goes to the receiving end of a wastewater treatment plant. The biochemical oxygen demand test (BOD5) relies heavily on the microorganism metabolic capability added to the test as seeding material. The seeding material in the testing is obtained from sewage sampling or from commercial sources. Specific organic pollutants that are present in paper and pulp mill effluent can only be degraded by specific microbes; therefore, common sewage or synthetic seed may lead to erroneous BOD5 estimations. In this study, specific microbial species were selected to evaluate their degradation efficiency, both individually and in combination. The microorganisms selected in the formulated seed exhibit BOD5 in a reproducible and synergistic manner. The formulation of this specific microbial consortium can be used to develop bioremediation strategies.