Review on recent developments on pulp and paper mill wastewater treatment

Recent developments of electro-oxidation in water treatment — A review

Every year the pulp and paper industry consumes billions of metres cubed of water and produces huge amounts of highly polluted wastewater that needs to be treated. Conventional techniques of wastewater treatment require a high energy input and their environmental impact is debatable. Thus, the need to find new sustainable, environmentally friendly and efficient treatment techniques is urgent. Microbial fuel cells (MFC) are the technology of the future since they simultaneously treat wastewater and produce clean energy. The historical development of this technology towards its application to wastewater treatment was described. The application of MFCs in pulp and paper wastewater treatment is a new and developing field of investigation that still needs to overcome many limitations before its use on an industrial scale. This article reviews the limits of conventional treatment methods and the current state of the art MFC systems for pulp and paper wastewater treatment. The paper provides an overview of the electrogenic microorganisms able to produce electricity from pulp and paper wastewater. The bacteria, isolated at different stages of pulp and papermaking, are best suited for electrogenic activity in harsh environments. It was shown that MFC technology fully meets the requirements of sustainable pulp and paper wastewater treatment and, in terms of the input-output energy balance, remains energetically and environmentally competitive when compared to conventional treatment methods.

Limits and perspectives of pulp and paper industry wastewater treatment – A review

ZEN AND THE ART OF MOTORCYCLE MAINTENANCE: An Inquiry into Values, Robert M. Pirsig, HarperCollins Publishers, New York 1974, reprint 2005, 430 pages, $13.95. [ILLUSTRATION OMITTED] Robert Pirsig's Zen and the Art of Motorcycle Maintenance (ZMM) metaphorically outlines the intellectual journey that the War Machine as an institution needs to take in order to reform itself. The perfect place for this reform to begin is in the military's first operational war fighting school, the Army's School of Advanced Military Studies (SAMS). Students at SAMS are reading ZMM in the true spirit of the school, the spirit of intellectual reform. Brigadier General Huba Wass de Czege started SAMS in the early 1980s when he realized that the Army as an institution could not reform itself from the inside, from the topdown. SAMS students learn to think for themselves, freeing themselves from the doctrinal Procrustean bed of black-and-white thinking. ZMM can help us challenge our unconscious schemata of categorical thinking that force us into seeing the world in functional hierarchies made up of block-and-line charts and examine our unconscious conflation of what's in our minds with what's in the world--the reification of our mental models, theories, and myths. ZMM is a timeless classic accessible to anyone courageous enough to challenge his or her own convictions. The understanding gained is not about good old-fashioned heroic, warrior leadership; it is not about decision-making; it is not about problem-solving. It is about critical reasoning. ZMM will not leave the reflective person unaffected. Introduction by LTC Timothy Challans, U.S. Army Retired, Ph.D. Zen and the Art of Motorcycle Maintenance is a bizarre title for a serious piece of literature, yet the title could not be more fitting. The philosophical quandaries in which the narrator engages proffer the reader an opportunity to expand upon traditionally held Western thoughts and values. The storyline is not typical of military readings, but unfortunately neither is the subject of critical thinking, which this book is all about. The title conjures images of Buddhist monks in secluded meditation, but also draws upon imagery of motorcycle maintenance to attract an audience with a proclivity for Western thinking into "an inquiry into values" and serious dialogue on logical reasoning and intuitive judgments about "quality." While taking a cursory, but grounding, tour through 2,500 years of philosophical evolution, the book challenges the reader to consider the value of self-reflection in order to increase the reader's capacity for critical thinking. It is a philosophically engaging modern epic well worth reading. It is not a manual for fixing motorcycles, nor will it have you sitting cross-legged in trancelike meditation, but it will make you scratch your head, challenge the way you think, and make you rethink the way you live. Robert Pirsig uses a father-son motorcycle trip across the northern region and west coast of the U.S. as the backdrop upon which he paints a candid picture of a well-educated, middle-aged man--presumably the author himself--struggling with his sanity. The narrator, previously subjected to electroshock therapy that left mental voids, is physically retracing his past and exploring the philosophical debates and discovery that he was previously obsessed with and which left him committed to an asylum. It is a captivating story filled with imagery to which the reader can easily relate, but the true power of the work is found in Pirsig's ability to use the story to pull the reader through a lesson on early Western philosophy while comparing it to aspects of Eastern philosophy. The narrator navigates through early Greek philosophical developments while drifting through periods of deep internal reflection, contemplating the meaning of artifacts that remain and memories that surface from his life before therapy. …

Zen and the Art of Motorcycle Maintenance: An Inquiry into Values

Paper industry is adopting zero liquid effluent technologies to reduce fresh water use and meet environmental regulations, which implies water circuits closure and the progressive accumulation of pollutants that must be removed before water re-use and final wastewater discharge. The traditional water treatment technologies that are used in paper mills (such as dissolve air flotation or biological treatment) are not able to remove recalcitrant contaminants. Therefore, advanced water treatment technologies, such as advanced oxidation processes (AOPs), are being included in industrial wastewater treatment chains aiming to either improve water biodegradability or its final quality. A
deep review of the current state of the art regarding the use of AOPs for the treatment of the organic load of effluents from the paper industry is herein addressed considering mature and emerging treatments for a sustainable water use in this sector. Wastewater composition, which is highly dependent of the raw materials being used in the mills, the selected AOP itself, and its combination with other technologies, will determine the viability of the treatment. In general, all AOPs have been reported to achieve good organics removal efficiencies (COD removal >40%; and about an extra 20% if AOPs are combined with biological stages). Particularly, ozonation has been the most extensively reported and successfully implemented AOP at an industrial scale for
effluent treatment or reuse within pulp and paper mills; although Fenton processes (photo-Fenton particularly) have actually addressed better oxidative results (COD
removal ≈65-75%) at lab scale, but still need further development at large scale.

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The application of advanced oxidation technologies to the treatment of effluents from the pulp and paper industry: a review.

Merits of ozonation and catalytic ozonation pre-treatment in the algal treatment of pulp and paper mill effluents.

Quantitative structure-activity relationship (QSAR) modelling is a major tool employed in the prediction of various endpoints. However, current QSAR literature is missing a full understanding of the impact of quantum chemical calculation methods on the estimation of molecular descriptors and model performance. Here, we provide a comprehensive analysis of the quantitative effects of different geometry optimization methods (semi-empirical, ab initio Hartee-Fock and density functional theory) on the molecular descriptors. Using experimental binding affinity to human serum albumin (HSA) data, we comparatively investigated the influence of employing descriptors derived from three calculation methods on the QSAR models. We propose a 4-descriptor QSAR model in line with the OECD validation principles for the prediction of drug binding affinity to HSA (log KHSA) as a potential tool for drug development. We also confirm the prediction capability of the proposed model on a heterogeneous external set of chemicals. Furthermore, we recommend an activity-independent rational approach for the selection of geometry optimization method for an improved QSAR model development.

Impact of geometry optimization methods on QSAR modelling: A case study for predicting human serum albumin binding affinity

Interaction between a Synthetic Dye Bath and Selenium in Their Toxicity to Dunaliella tertiolecta under Two Light Intensities

Two data sets on the cytotoxicity of diverse chemicals to topminnow (Poeciliopsis lucida) hepatoma cell line (PLHC-1) were modelled with quantitative structure-toxicity relationship (QSTR). The data sets are based on 3-amino-7-dimethylamino-2-methylphenazine hydrochloride (NR) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays representing lysosomal damage and metabolic impairment, respectively. The descriptors were calculated with DRAGON 6 and SPARTAN 10 software packages. Descriptor selection was made by 'all subset' and genetic algorithm-based features implemented in QSARINS software. The proposed QSTR models were validated both internally and externally. For both endpoints, statistically satisfactory QSTR models were generated with nTr = 39; r2Tr = 0.782; RMSETr = 0.466; nTest = 18; r2Test = 0.799; RMSETest = 0.360 for NR-based model and nTr = 32; r2Tr = 0.775; RMSETr = 0.460; nTest = 10; r2Test = 0.864; RMSETest = 0.290 for MTT-based model. Additionally, the QSTR models generated for NR and MTT endpoints were used to predict the cytotoxicity of an external set of 657 and 652 diverse chemicals with structural coverage of 98.6% and 98.3%, respectively. A moderate correlation was observed between the experimental in vivo and predicted in vitro values for external set chemicals. The QSTR models may provide an initial, rapid screening and prioritization of these diverse chemicals for the acute fish toxicity assessment and reduce the need for extensive in vivo toxicity testing.

M. Türker Saçan

Papers

Merits of ozonation and catalytic ozonation pre-treatment in the algal treatment of pulp and paper mill effluents.

Impact of geometry optimization methods on QSAR modelling: A case study for predicting human serum albumin binding affinity

Interaction between a Synthetic Dye Bath and Selenium in Their Toxicity to Dunaliella tertiolecta under Two Light Intensities

On the prediction of cytotoxicity of diverse chemicals for topminnow (Poeciliopsis lucida) hepatoma cell line, PLHC-1$.