Sorption isotherms and kinetics of chromium uptake from wastewater using natural sorbent material

Chromium [VI] which exists in many industrial wastewater is considered highly toxic. The aim of the present investigation was to study the reduction of chromium [VI] to chromium [III] and then removing it with the help of weathered basalt andesite products. Reduction of the chromium [VI] to chromium [III] by hydrazinium sulfate was investigated. The influence of hydronium ion concentration, contact time, hydrazinium sulphate dosage and temperature has been tested in batch runs. The process was found to be acid, temperature and concentration dependent. The suitability of weathered basalt andesite products as a potential sorbent was assessed for the removal of chromium [III] following batch mode of operation. The effect of various parameters such as hydronium ion concentration, shaking time, sorbent dose, initial metal ion concentration and temperature on the removal of chromium [III] from aqueous solution was studied. Thermodynamic parameters [DH° DS° and DG°] for the sorption process were evaluated. Analysis of sorption obtained results showed that the sorption pattern followed the Freundlich, Langmuir and Dubinin-Kaganer-Radushkevich isotherms. The process follows pseudo second order rate and surface diffusion is identified as the predominating mechanism. The sorption process was shown to be reversible by the recovery of sorbed chromium [III] upon extraction with 0.5 M nitric acid. The sorbent, before and after sorption, was characterized by fourier transform infrared spectrometer, X-ray diffraction, scanning electron microscope, transmision electron microscope and thermo-gravimetric analyse methodes. An increase in crystallanity after sorption of chromium was observed. An industrial effluent was successfully treated with the same sorbent with convincing results

Synthesis and physico-chemical studies of some polymers for removing of some heavy metal ions of industrial wastewater

The chemical contaminations of wide range of toxic derivatives in water, in particular heavy metal ions and dyes is a serious environmental problem owing to their potential human toxicity. Therefore, there is a need to develop technologies that can remove toxic pollutants from the wastewater. Adsorption is one of choices used for treating industrial effluents and a useful tool for protecting the environment. In particular, adsorption on synthetic, natural polymers and their derivatives is known to remove pollutants from water. The importance of the synthetic polymers has increased due to their high selectively, stability at elevated temperature and sensitivity to the high concentration of ions. One of the major applications of epoxy and its many derivatives is based on its ability to bind strongly heavy and toxic metal ions. This study will focus on the synthesis of two types of polymers, the first one was carried by suspension polymerization of epoxy resin, methyl methacrylate [MMA] and divinyl benzene [DVB] mixtures which have been modified though epoxy functions in two steps: [i] by treating with polyamine and [ii] by subsequent reaction with potassium chloroacetate. The second type which is a new low cost adsorbent was prepared by modified polysaccharides for example resin was polymerized epoxy resin and cross linked starch mixtures in two steps; [i] by treating with polyamine and [ii] by subsequent reaction with potassium mono chloroacetate, that to increase the efficient sorbet for removal of Cu[II] and Ni[II] ions

Performance evaluation of electrocoagulation process for diazinon removal from aqueous environments by using iron electrodes

The present study investigates the removal of pesticide by electrocoagulation process. A glass tank in 1.56 L volume with four iron plate electrodes was used to perform the experiments. The electrodes connected to a DC power supply [bipolar mode]. The tank was filled with synthetic wastewater were which contained diazinon pesticide in concentration of 10, 50 and 100 mg/L. The percent of diazinon removal was measured at pH= 3, 7 and 10 and in electric potential range of 20-40V by thin layer chromatography method. The results indicated that initial concentration of diazinon can affect efficiency removal and for higher concentrations of diazinon, higher electrical potential or more reaction time is needed. The results showed that for a given time, the removal efficiency increased significantly with increase of voltage. The highest electrical potential [40V] produced the quickest treatment with >99% diazinon reduction occurring after 60 min. The final pH for iron electrodes was always higher than initial pH. Finally it can be concluded that electrocoagulation process [using iron electrodes] is a reliable, efficient and cost-effective method for removal of diazinon from aqueous environments, especially designed for pH=3 and voltage40V

Percepção de risco no trabalho de processamento de resíduos industriais e de suas consequências sobre a saúde e meio ambiente / Risk perception at work in waste processing plant and of their consequences on health and environment

Introdução: A percepção de riscos constitui um processo social que reflete preocupações com a proteção da saúde, a segurança e o meio ambiente. Este estudo apresenta a percepção de riscos entre trabalhadores de uma planta de processamento de resíduo industrial. Metodologia: Foram realizadas entrevistas semi-estruturadas com questões referentes à percepção quanto a riscos referentes à saúde presentes no trabalho, riscos considerados mais ou menos críticos, tarefas mais arriscadas, possibilidade de trabalhar de forma segura, existência de problemas de saúde relacionados ao trabalho, possibilidade de problemas futuros de saúde decorrentes de exposições ocupacionais, informação sobre riscos à saúde por ocasião da admissão na empresa, adequação das medidas de proteção adotadas etc. Resultados: Foram entrevistados 27 trabalhadores. O risco à saúde mais percebido foi o de contaminação com resíduos (52%), seguido do risco de acidentes quando da manutenção de máquinas. 43% dos trabalhadores não expressaram receio de executar qualquer tarefa. 24% dos trabalhadores relataram cefaleia; 12%, epigastralgia. 35% dos trabalhadores temem apresentar câncer ocupacional e 25% apresentaram medo indefinido com relação a problemas futuros de saúde. 50% dos trabalhadores apontam apenas uso de equipamento de proteção individual como medida adotada para trabalhar de forma segura, 60% relataram terem sido informados dos riscos à saúde decorrentes do trabalho quando da contratação. 96,3% consideram a atividade de processamento de resíduo importante para a sociedade. Conclusões: As informações oferecidas pelos trabalhadores apontaram riscos não previstos e não identificados quando da construção da planta assim como problemas na gestão de riscos, de informação e comunicação da empresa.

This study applies the risk perception analytical methodology. It took place with workers at industrial waste processing plant. The methodological approach was based on participatory observation and semi-structured interviews with 27 workers selected. The results show that the more perceived risk was the contamination with waste following by risk of accident in maintenance of mechanical apparatus. 43% didn't express apprehension in perform whatever task. 24% of workers related headache and 12% stomach-ache. 35% were afraid of occupational cancer and 25% of other health problems in future. 50% of workers related adopt as safery measure only the use of individual protection equipment. 60% had been informed of health risk of work when was hired. 93,3 % evaluated the waste processing plant important for society, The information offered by workers point Out health risks not foreseen and not identified in plant construction, as well problems in risk management and problems in information and communication process.

A study on sludge minimization during the treatment of pickling effluent.

In pickling industries, a lot of sludge is generated during the treatment of pickling effluent and there is severe problem of its disposal. Disposal of this sludge as per the Hazardous Waste (Management & Handling) Rules, 1989 is not easy. Its transportation and construction of lined disposal sites pose very severe problems. In the normal practice, the sludge is being disposed of at the sides of roads and railway tracks to fill low lying areas. This may cause serious health hazards. Considering these problems, a study has been undertaken to minimize the sludge generation during the treatment of pickling effluent by neutralizing it with lime, sodium hydroxide and combination of both. An attempt has been made to do an economic evaluation of the above process.

Environmentally safe design of tailing dams for the management of iron ore tailings in Indian context.

The need for the disposal of iron ore tailings in an enviornmentally firiendly manner is of great concern. This paper investigates the soil engineering properties for the construction of iron ore tailing dam, its foundation, construction materials and design data used for the construction analysis of the tailing dam. Geophysical investigations were carried out to establish the bedrock below the spillway. A computer programme taking into account the Swedish Slip Circle Method of analysis was used in the stability analysis of dam. It also focuses on the charactierstics of the tailings reponsible for the determination of optimum size of tailing pond for the containment of the tailings. The studies on the settling characteristics of tailings indicate much less area in comparison to the area provided in the existing tailing ponds in India. In the proposed scheme, it is suggested to provide an additional unit of sedimentation tank before the disposal of tailings to the tailing pond.

Value added eco-friendly products from tannery solid wastes.

Chrome shavings are the prominent solid wastes in tanning industry. Since chromium is known for its toxicity, the disposal of chrome shavings has been identified as a serious problem from the environmental point of view. At present, the popular utilization mode for chrome shavings is the manufacture of leather boards and related products. But this does not offer complete utilization of chrome shavings. Moreover, return per ton of chrome shavings is low if used for leather board production. In view of this, two processes have been developed to offer an alternative and better solution for the disposal of chrome shavings.The first process is preparation of parchment like membrane and the second process is related to development of leather like material. These products are analyzed for their mechanical behavior and other physicochemical properties. Parchment membrane can be used in the preparation of lampshades, chandeliers, wall hangers, table tops etc. and leather like material can be used in the preparation of chappal uppers, hand bags, purses, valets etc. The utilization of the chrome shavings in preparation of those two products not only reduces the environmental pollution but at the same time value added products can also be obtained.

Surfactant modified coir pith, an agricultural solid waste as adsorbent for phosphate removal and fertilizer carrier to control phosphate release.

The surface of coir pith, an agricultural solid waste was modified using a cationic surfactant, hexadecyltrimethylammonium bromide (HDTMA) and the modified coir pith was investigated to assess the capacity for the removal of phosphate from aqueous solution. Optimum pH for maximum phosphate adsorption was found to be 4.0. Langmuir and Freundlich isotherms were used to model the adsorption equilibrium data. Kinetic studies showed that the adsorption obeyed second order kinetics. Thermodynamic parameters were evaluated and the overall adsorption process was spontaneous and endothermic. Effect of coexisting anions has also been studied. The feasibility of using spent adsorbent as fertilizer carrier to control phosphate release was also investigated.

Removal of trace chromium (VI) from contaminated water: bio-sorption by Ipomea aquatica.

Ipomea aquatica is a wetland plant, which floats in water bodies and is being used as a vegetable. This plant has ability to remove Cr(VI) from the contaminated water by transforming Cr (VI) to Cr (III). This adsorption of Cr(VI) basically takes place in roots of this plant. The contact time required to bring down Cr(VI) concentration below the permissible level (0.05 mg/1) is 30 to 40 days for this plant, and that varies with varying initial concentration. The lower level of contamination requires greater contact time than the higher one to bring down Cr(VI) below the permissible level. Recovery (94 +/- 1%) of chromium from the treated plant has been reported in this paper, and at the same time disposal problem also dose not arise. The study revealed that the plant Ipomea aquatica adsorbs Cr(VI) from the contaminated water very slowly compared to the other reported plants.

Identification and classification of industrial solid wastes in ammonia unit of Razi petrochemical complex and feasibility of waste minimization

Petrochemical industries are considered as strategic and important sectors in economic development of Iran. Razi petrochemical factory is one of complex in Iran, established in 1970 with 100 hectare. In this research, the possibility of waste minimization in the ammonia unit of Razi petrochemical complex with about 1000 tons per year was studied for a period of 18 months from September 2003 to April 2005. More than 20 site visits were conducted and the required information was collected. Factors such as industrial solid wastes quality and quantity, sources of generation, production period and the present management practice, were studied. Petrochemical solid wastes were classified based on the recommended method of the United Nations and appropriate policies were suggested for waste minimization. The collected results of this study show production of 185 tons of industrial solid wastes from 45 sources which contained 68.5% catalysts, 10.25% metal barrels, 18.61% aluminum ball, 2.62% plastic barrels and 0.02% paper. 93.3% of these wastes were generated as the result of catalysts change, 3.3% as the result of using chemicals and oils, 1.7% as the result of methanol solution amid application, and 1.1% because of aluminum ball changes. Based on the UNEP methods, the ammonia unit wastes classified as 19/7%hazadrous and 87,12% non hazardous. At present 87.12% of these wastes are being dumped in the area and 12.88% are sold. Proposed procedures for waste minimization contain 68.5% reuse and recycling and 31.5% recycling

Relevamiento de reactores anaerobios en América Latina / Anaerobic reactors survey in Latin America

Se realiza un relevamiento de los reactores anaerobios construídos en América Latina. Se procesan los distintos aspectos de la información, a saber, cantidades, volúmenes, tipos de reactores, evolución en el tiempo, tipo de efluente y origen de la tecnología. La participación de la región en el desarrollo de la tecnología de la digestión anaerobia para el tratamiento de efluentes resulta ser importante y en franco desarrollo, presentando además una importante base tecnológica nacional. Se presentan asimismo datos de parámetros de diseño para los principales tipos de efluentes que surgen de los reactores en funcionamiento

Poluiçäo industrial: caracterizaçäo e controle / Industrial Pollution: caracterization and control

A poluiçäo ambiental é um fenômeno que está aliado a duas características que devem ser levadas em conta em qualquer estudo: a primeira, de que a produçäo de resíduos está ligada intrinsicamente ao desenvolvimento do ser humano e à vida, existindo täo somente às águas, o ar e o solo como receptores desses recursos possui uma capacidade finita de autodepuraçäo, limitada no tempo e no espaço. Os problemas sérios de poluiçäo ambiental - água, ar e por resíduos sólidos, resultantes do imenso parque industrial, exigem do Estado de Säo Paulo, uma atitude firme e decidida para seu equacionamento

O emprego de reatores anaeróbios no tratamento de despejos líquidos de indústrias de celulose e papel / The use of anaerobic reactors for pulp and paper mills effluents treatment

Descrevem-se os processos anaeróbios de tratamento de efluentes líquidos e sua aplicaçäo na indústria de celulose e papel. Apresenta-se revisäo bibliográfica da literatura internacional mostrando problemas ambientais gerados por esse tipo de indústria. Säo apresentados quadros contendo parâmetros operacionais e discutidos tipos de tratamento anaeróbios. Säo apresentados e comentados os resultados obtidos durante a operaçäo de uma unidade piloto de tratamento de despejos líquidos de uma indústria de cartöes e cartolinas. Essa unidade possuia 4m*3, e era tipo reator de manto de iodo. Esse sistema trabalhou a temperaturas entre 18 e 30§C durante 820 dias. Nos últimos 520 dias, após ter atingido o regime estabilizado, foi monitorado variando-se o tempo de detençäo hidráulica de 8 a 20 horas. Os despejos afluentes apresentaram valores médios de DQO e DBO de 670 g.m*-3 e 320g.m*-3 respectivamente, e as taxas de aplicaçäo atingiram ao máximo de 2,5 Kg DQO. m*-3. d*-1, para um tempo de detençäo hidraúlica de 8 horas. Na condiçäo de máxima taxa de aplicaçäo observou-se remoçöes de DQO e DBO de 56,5 e 59,3 por cento. Embora os despejos apresentassem elevada concentraçäo de sólidos suspensos, o reator näo demonstrou problemas operacionais. A produçäo do gás para a máxima taxa de aplicaçäo foi de 0,07 m*3 Kg*-1 DQO removida

Controle de poluiçäo ambiental: implantaçäo de sistema de financiamento / Environmental pollution control: implement a financing system

O presente trabalho tem por objetivo apresentar uma proposta para a implantaçäo de um sistema de financiamento para controle de poluiçäo ambiental. Assim, o trabalho é composto de quatro partes básicas. A primeira compreende uma abordagem introdutória, na qual säo apresentados os princípios e conceitos relacionados à poluiçäo ambiental. Na segunda parte é descrita a evoluçäo do controle da poluiçäo ambiental no Estado de Säo Paulo, abrangendo períodos, legislaçäo, atribuiçöes e aspectos institucionais. O programa de financiamento para controle de poluiçäo ambiental de origem industrial para o Estado de Säo Paulo, como exemplo, é detalhado na terceira parte do trabalho, abordando suas características, a evoluçäo do programa, as estruturas legal e administrativa utilizadas em seu desenvolvimento e diversos resultados obtidos em termos físico-ambientais e econômico-sociais, caracterizando a implantaçäo e o desenvolvimento do programa considerado. A quarta parte apresenta entäo uma proposta para implantaçäo de sistema de financiamento para controle de poluiçäo ambiental, em condiçöes de ser utilizado nos diversos níveis do Governo, particularmente a nível de Estado. O trabalho realizado permite considerar a importância do sistema de financiamento do tipo descrito como instrumento de apoio às açöes de controle de poluiçäo, estimulador de estudos para determinaçäo de custos de controle de poluiçäo e, consequentemente, fator de induçäo para a formulaçäo de política de controle de poluiçäo ambiental clara e definida, adequada às situaçöes locais e regionais, conduzindo à melhoria de suas condiçöes ambientais e, em decorrência, da qualidade de vida.

Tratamento de águas residuárias da "Indústrias de Papel Simäo S.A.": influência na qualidade do Rio Paraíba do Sul

Procura-se demonstrar a influência da implantaçäo de um sistema de tratamento de águas residuárias de uma indústria de Papel e Celulose na qualidade das águas do Rio Paraíba do Sul. A avaliaçäo baseou-se na amostragem das águas residuárias da indústria e do corpo receptor. No corpo receptor estabeleceram-se dois pontos de amostragens localizados à montante das captaçöes dos municípios de Jacareí e Säo José dos Campos.

Resíduos sólidos (lodos) originados do pré-tratamento de águas residuárias das indústrias da regiäo metropolitana de Säo Paulo

Sugere-se 5 categorias de resíduos provenientes dos pré-tratamentos de efluentes liquídos: biodegradáveis; relativamente biodegradáveis; contendo metais pesados e/ou tóxicos; com teores de óleos e graxas; inertes. Uma grande quantidade de indústrias foram pesquisadas e os resultados foram utilizados como base para as conclusöes contidas neste trabalho. De acordo com levantamentos efetuados em 500 representativas indústrias, a quantidade de lodo de pré-tratamentos apresentam-se soluçöes para o tratamento e a disposiçäo final destes resíduos e também recomendam-se medidas que possibilitem a implantaçäo de uma política destinada à soluçäo deste problema na Regiäo Metropolitana de Säo Paulo.