Anaerobic digestion of biowaste in Indian municipalities: Effects on energy, fertilizers, water and the local environment

Anaerobic digestion (AD) of biowaste seems promising to provide renewable energy (biogas) and organic fertilizers (digestate) and mitigate environmental pollution in India. Intersectoral analyses of biowaste management in municipalities are needed to reveal benefits and trade-offs of AD at the implementation-level. Therefore, we applied material flow analyses (MFAs) to quantify effects of potential AD treatment of biowaste on energy and fertilizer supply, water consumption and environmental pollution in two villages, two towns and two cities in Maharashtra. Results show that in villages AD of available manure and crop residues can cover over half of the energy consumption for cooking (EC) and reduce firewood dependency. In towns and cities, AD of municipal biowaste is more relevant for organic fertilizer supply and pollution control because digestate can provide up to several times the nutrient requirements for crop production, but can harm ecosystems when discharged to the environment. Hence, in addition to energy from municipal biowaste - which can supply 4-6% of EC - digestate valorisation seems vital but requires appropriate post-treatment, quality control and trust building with farmers. To minimize trade-offs, water-saving options should be considered because 2-20% of current groundwater abstraction in municipalities is required to treat all available biowaste with ’wet’ AD systems compared to <3% with ’dry’ AD systems. We conclude that biowaste management with AD requires contextualized solutions in the setting of energy, fertilizers and water at the implementation-level to conceive valorization strategies for all AD products, reduce environmental pollution and minimize trade-offs with water resources

Removal and fouling mechanisms in nanofiltration of polysaccharide solutions

Tubular membrane filtration is an important process when feed waters with a relatively high solids content are filtered. Such solids would normally have to be removed in a pre-treatment stage if spiral wound modules are to be used. High solids content occurs for example in high turbidity surface waters, wastewaters that contain fibrous materials or in waters where coagulants are added. Tubular membranes can be used directly in nanofiltration (NF) and in this study fouling by a solution containing polysaccharides is examined. The study was designed in view of a wastewater recycling application where polysaccharides like cellulose are a major constituent of the effluent organic matter (EfOM) and colloidal organics. The investigation was performed with various organic compounds and varying solution chemistry namely pH and ionic strength. Two solutes in several concentrations have been used: Cellulose (particulate) and microcrystalline cellulose (colloidal) in addition with various CaCl2 and NaCl concentrations. The operating parameters investigated were cross flow velocity, transmembrane pressure (TMP) and pH. Membranes were cleaned after each filtration experiment and flux recovery was measured. As a general trend, it was observed that with increasing cellulose concentration fouling increases and that solution chemistry plays an important role in the association of foulants with the membranes. The permeability decreases for high and neutral pH conditions in the presence of salt ions. Calcium affects the flux more than sodium. The permeability at acidic pH values is relatively low and not influenced by the ions as much as for other pH conditions. Electrostatic interactions between membrane, salt ions and cellulose can explain this behaviour. Calcium ions were confirmed to play an important role in membrane fouling. Increasing cross flow velocity decreases the reversible fouling but increases the irreversible fouling

Математическое моделирование гидрогазодинамики и тепломассопереноса в сдвиговых течениях реологически сложных вязких сред: идеи, результаты, перспективы прогноза процессов

В настоящей работе представлен критический анализ проблем, результатов и перспектив исследований течений сложных по структуре/реологии вязких сред в трубопроводных системах (узлах оборудования нефтегазовой, химико-технологической и тепло-энергетической промышленности), испытывающих на себе влияние неизотермичности, нестационарности, переменности тепло- и реофизических свойств, внешних полей от действия инерционных и гравитационных сил, особенностей формы поперечного сечения проточной части. Особое внимание уделяется: технологиям моделирования углеводородов (тяжелых нефтей, масел) при их транспортировке на участках труб/каналов с интенсивным тепломассообменом; определению мер повышения энергоэффективности и стабильности функционирования оборудования, изучению опыта анализа проблем коррозии энергонапряженных элементов, а также их очистки от загрязнений

Removal of hormones and pharmaceuticals in the Advanced Water Recycling Demonstration Plant in Queensland, Australia

An advanced water recycling demonstration plant was employed to investigate the effectiveness of a number of treatment technologies in the removal of some residuals of commonly prescribed pharmaceuticals as well as natural and synthetic hormones found in sewage. Analysis of targeted compounds was carried out by solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). Initial tests were undertaken to determine the background concentrations of the analytes during various stages of treatment. Subsequent tests, undertaken by spiking with standard solutions of the target compounds provided further information on the removal efficiencies of some selected treatment modules. The results of the study indicate that while ozonation, microfiltration and nanofiltration were partially effective; treatment by reverse osmosis was the most universally successful in the removal of the target residuals. While significantly more data is required for a full evaluation, this initial investigation suggests that reverse osmosis may be an effective means of removing a wider range of pharmaceutically active residuals and hormones from treated sewage

The role of membrane processes in municipal wastewater reclamation and reuse

Wastewater reuse presents a promising solution to the growing pressure on water resources. However, wastewater reuse implementation faces obstacles that include insufficient public acceptance, technical, economic and hygienic risks and further uncertainties caused by a lack of awareness, accepted standards, uniform guidelines and legislation. So far, there are no supranational regulations on water reuse in Europe and further development is slowed by lack of widely accepted standards e.g. in terms of required water quality, treatment technology and distribution system design and operation. Treatment technology encompasses a vast number of options and membrane processes are regarded as key elements of advanced wastewater reclamation and reuse schemes and are included in a number of prominent schemes world-wide, e.g. for artificial groundwater recharge, indirect potable reuse as well as for industrial process water production. For dual reticulation purposes in urban areas two types of systems have been built, a centralised type of treatment with dual membrane processes, including e.g. microfiltration (MF) and reverse osmosis (RO), and small scale systems using membrane bioreactors. This paper will provide an overview of the status of membranes processes in wastewater reclamation and reuse world-wide and will depict their potential role in promoting more sustainable water use patterns

In vitro studies and preliminary in vivo evaluation of silicified concentrated collagen hydrogels

Hybrid and nanocomposite silicacollagen materials derived from concentrated collagen hydrogels were evaluated in vitro and in vivo to establish their potentialities for biological dressings. Silicification significantly improved the mechanical and thermal stability of the collagen network within the hybrid systems. Nanocomposites were found to favor the metabolic activity of immobilized human dermal fibroblastswhile decreasing the hydrogel contraction. Cell adhesion experiments suggested that in vitro cell behavior was dictated by mechanical properties and surface structure of the scaffold. First-to-date in vivo implantation of bulk hydrogels in subcutaneous sites of rats was performed over the vascular inflammatory period. These materials were colonized and vascularized without inducing strong inflammatory response. These data raise reasonable hope for the future application of silicacollagen biomaterials as biological dressings.Fil: Desimone, Martín Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Hélary, Christophe. Université Pierre et Marie Curie; FranciaFil: Quignard, Sandrine. Université Pierre et Marie Curie; FranciaFil: Rietveld, Ivo B. Universite de Paris; FranciaFil: Bataille, Clement. Université de Versailles Saint-quentin-en-yvelines.; FranciaFil: Copello, Guillermo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Mosser, Gervaise. Université Pierre et Marie Curie; FranciaFil: Giraud Guille, Marie-Madeleine. Université Pierre et Marie Curie; FranciaFil: Livage, Jacques. Université Pierre et Marie Curie; FranciaFil: Meddahi Pellé, Anne. Université de Versailles Saint-quentin-en-yvelines.; FranciaFil: Coradin, Thibaud. Université Pierre et Marie Curie; Franci