Electric conversion treatment of cobalt-containing wastewater

Long-term accumulation of cobalt-containing wastewater may also pollute groundwater and cause a large amount of loss of valuable metals. Therefore, the comprehensive utilization of cobalt-containing wastewater must be realized, especially cobalt itself is a very important strategic resource. This paper proposes a membrane electroconversion method to separate cobalt ions from cobalt-containing wastewater and prepare cobalt hydroxide. In addition, the electrolysis process was optimized, and single-factor experiments such as the initial concentration, cobalt ions, current density, temperature et al., and economic calculations such as current efficiency were explored. And the electrolysis product was calcined as the precursor to obtain the oxide Co3O4, and the calcining experiment was also optimized. In this concentration range, more than 90% of cobalt can be recovered within 2 h.

Assessment of Groundwater Quality for Drinking Purpose in an Industrial Area, Dumai City, Riau, Indonesia.

Groundwater is the main water resource especially for daily water needs. Population growth and urbanization have increased demand for water while the availability of groundwater has decreased both in quality and quantity. Various human activities also produce industrial, agriculture and municipal waste that can pollute groundwater through leaching process. The purposes of this study are to determine the quality of groundwater around tofu industrial factory and its evaluation for drinking water based on Health Minister Regulation No.492/MENKES/PER/IV/2010 and Government Regulation No.82 2001.The temperature, pH, total dissolved solids (TDS) and electrical conductivity (EC) were measured by using YSI-Pro. Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) were measured based on SNI 06-6989.2.2009 test method and SNI 06-698.72.2009 test method, respectively. Physically, groundwater had temperature average 28,60C, TDS 243 mg/L and EC 396 µS/cm. Almost all groundwater were acidic with pH average 5,6 and did not meet the drinking water quality requirements. Groundwater had COD average 78 mg/L, BOD average 36 mg/L and it were classified into moderate-heavy pollution. It indicated that groundwater may have been contaminated by organic material from tofu industrial wastewater. Therefore, groundwater should not be used as a source of drinking water.

On-Site Sanitation Systems for Low-Income Countries

On-site sanitation systems, the commonest sanitation technologies in low-income countries, are central to the elimination of open defecation in such countries. Nevertheless, their selection and application in the physical and socio-economic environment of low-income settings could be a complex and challenging task. Poorly designed and constructed facilities could pollute groundwater resources and create nuisances to the user and the general public. Meanwhile, local authorities in these countries often lack the human resource with the requisite technical capacity to analyse situations and recommend appropriate solutions. This calls for guidance in the most crucial technical decisions that affect the safe usage and environmental sustainability of on-site sanitation technologies. This Chapter reviews salient standards and guidelines for the selection of appropriate technologies, prevention of groundwater pollution, control of odor and fly nuisance, structural stability and safety of the latrine user.

La producción de maíz en Sinaloa, México, y sus implicaciones para el medio ambiente/ The Production of Corn in Sinaloa, Mexico and its Implications for the Environment

La sustitución de cultivos acarrea problemas de contaminación al ambiente, principalmente al suelo y agua. El objetivo de este artículo es analizar la evolución de la producción de maíz blanco en Sinaloa y sus implicaciones para el ambiente, derivadas de la sustitución de cultivos. La metodología empleada es el cálculo del número índice de crecimiento de la producción y la superficie sembrada de maíz, por grupos de cultivos y los cinco cultivos básicos en Sinaloa. El periodo analizado, de 1980 a 2016. Sinaloa se ha convertido en el principal productor de maíz blanco en las últimas décadas; su cultivo es intensivo en agroquímicos, lo que puede ocasionar problemas de contaminación al suelo y agua. La superficie sembrada se incrementó 287 % de 1980 a 2016, especialmente en áreas irrigadas. Cereales y hortalizas son los grupos que más crecieron y representan el 72,9 % del valor de la producción. Los procesos productivos involucran costos ambientales como los resultantes de la aplicación de fertilizantes y plaguicidas, que sin un adecuado control deterioran el suelo, contaminan los mantos freáticos, la flora, la fauna y la salud humana. Abstract The substitution of crops leads to problems of contamination to the environment, mainly to soil and water. The objective of this article is to analyze the evolution of the production of white corn in Sinaloa and its implications on the environment, derived from the substitution of crops. The methodology used is the calculation of the index number of growth of the production and the area planted with corn, by crop groups and the five basic crops in Sinaloa. The period analyzed is 1980 to 2016. Sinaloa has become the main producer of white corn in recent decades; its cultivation is intensive in agrochemicals, which can cause pollution problems to soil and water. The planted area increased 287 % from 1980 to 2016, especially in irrigated areas. Cereals and vegetables are the groups that grew the most and represent 72,9 % of the value of production. The productive processes involve environmental costs such as those resulting from the application of fertilizers and pesticides, which, without adequate control, deteriorate the soil, pollute groundwater, flora, fauna and human health.

Assessment of the Nutrients in the Leachate and the Groundwater Quality for Drinking and Farming around the Nkolfoulou Landfill in Yaoundé, Cameroon

This study focuses on the assessment of the nutrients in the leachate and the groundwater quality around the Nkolfoulou landfill in Yaoundé known in French as “Centre de Traitement de Déchets (CTD).” Landfilling generates leachate that can pollute groundwater. Leachate along with groundwater samples (n=1+13) was collected in January (long dry season) and May (long wet season) 2014 and explored for various parameters including pH, temperature, EC, turbidity, TDS, TA, TSS, TH, BOD5, COD, Na+, K+, Mg2+, Ca2+, NH4+, NO3−, Cl−, F−, SO42−, PO43−, HCO3−, and colour using standard methods. In the leachate samples, values of TSS (700.2 and 130.2 mg/L), BOD5 (140 mg/L), COD (1350 and 1750 mg/L), NH4+ (82.50 and 39.51 mg/L), NO3− (159.32 and 74.82 mg/L), and Cl− (702.69 and 345.50 mg/L) exceeded the Cameroonian standards for effluent discharge. All the values of pH and some values of turbidity (4.55 and 4.50 NTU) and NH4+ (0.51 and 0.73 mg/L) in the groundwater samples violated the Cameroonian standards for drinking water. Based on the water quality index (WQI), an average of 11.53% of groundwater samples was improper for drinking in both seasons. Based on the parameters assessed, all the samples complied with the standard set for irrigation, poultry, and livestock. The hazard quotient (HQ) and the hazard index (HI) of NO3− and F− for children and adults were <1, and hence, the increased non-cancer risks due to these ions through the drinking of groundwater was low. From the statistical analysis, the Nkolfoulou landfill may not be the main source of major ions to the nearby groundwater.

THE INTENSIFICATION OF THE PROCESS OF SLUDGE DEWATERING OF URBAN SEWAGE

Urban wastewater sludge is highly humid, large and poorly dehydrated. Dehydration of sludge in natural conditions has a number of shortcomings: low effi ciency, sludge areas require huge land areas, worsen the ecological situation, pollute groundwater, soil, etc. One way to eliminate the problem and improve the effi ciency of sludge dewatering in urban wastewater is to switch to mechanical dehydration using fl occulants. The work is devoted to the selection of the most eff ective fl occulant and was carried out on the natural sediments of the right-bank treatment facilities in Krasnoyarsk and the sewage treatment plants in the sett lement of Emelyanovo. The experiment showed that fl occulants Praestol 851BC and Zetag 7485 at a dose of 3 kg / t dry matt er of the precipitate have the greatest eff ectiveness.

On-Site Sanitation Systems for Low-Income Countries

On-site sanitation systems, the commonest sanitation technologies in low-income countries, are central to the elimination of open defecation in such countries. Nevertheless, their selection and application in the physical and socio-economic environment of low-income settings could be a complex and challenging task. Poorly designed and constructed facilities could pollute groundwater resources and create nuisances to the user and the general public. Meanwhile, local authorities in these countries often lack the human resource with the requisite technical capacity to analyse situations and recommend appropriate solutions. This calls for guidance in the most crucial technical decisions that affect the safe usage and environmental sustainability of on-site sanitation technologies. This Chapter reviews salient standards and guidelines for the selection of appropriate technologies, prevention of groundwater pollution, control of odor and fly nuisance, structural stability and safety of the latrine user.

Ground Characterization of Abandoned Open Pits Liable to Illegal Industrial Waste Dumping: A Case Study of Thailand’s Chachoengsao Province

This research has investigated the geotechnical properties of abandoned open pits in Thailand’s eastern province of Chachoengsao that could become targets for illegal industrial waste dumping. Out of a total of 11 districts, this research focuses on two districts, i.e. Plaengyao and Panom Sarakarm, due to the proximity to industrial estates and abundance of open pits. The findings reveal a very low permeability rate of Plaengyao’s surface soil, indicating that no open pits should be used as dumping sites as contaminants are captured by and deposited in the surface soil. Clay liner and surface drainage are needed to be considered for Landfills in Plaengyao district. In contrast, the surface soil of Panom Sarakarm district is of high permeability and thereby renders the utilization of open pits environmentally harmful since the dissolved contaminants can leach through the ground and pollute groundwater.

Factors Controlling the Distribution and Fate of Nitrate in the Unsaturated Zone and Groundwater in a Semiarid Agriculture Area

Overuse of fertilizers in agriculture could cause groundwater nitrate pollution. However, this is related to nitrate input, soil moisture movement (direction and rate), and depth of water table in (semi)arid areas, where nitrate can be preserved and nitrate loss by denitrification can be limited. A 18-m soil profile to water table in Daxing, Beijing shows that the nitrate is accumulated in the upper unsaturated zone and has not reached water table; and then groundwater nitrate remains at baseline level (5.6 mg/L). The soil moisture movement velocity is 0.28 m/yr based on nitrate use history. It takes another ~35 years for the moisture with high nitrate content to reach water table and pollute groundwater, to which attention should be paid in water quality management.

Analyze of Leachate Composition in the Dumpsites of East-Latgale Region

There are are 28 working or closed but not recultivated municipal solid waste dumpsites in East-Latgale now. A number of these dumpsites are situated near lakes, rivers, in old mineral quarries etc [3, 6]. All these dumpsites pollute groundwater, soil and present danger for human health. One of the dangerous factors is leachate which is generated in these dumpsites and which pollutes groundwate, soil and drinking water. The analysis of leachate sample chemical content in the biggest East-Latgale dumpsites “Ritini”, “Zvirgzdene”, “Zelceva” and “Mostovaja” has been done in 2002. The content of leachate depends on content of waste, dumpsite management etc. The most polluted leachate is in the biggest dumpsites of region – “Ritini” and “Zvirgzdene”. These are city dumpsites (Rezekne and Ludza). Significantly less polluted leachate is found in the dumpsites “Zelceva” and “Mostovaja”. This is valid for all analyzed parameters – COD, conductivity, Ntot., NH4 + and Cl.