Biological Oxygen Demand (in waste water treatment )

Textile industries are one of the largest consumers of water as well as the producers of large quantities of wastewater effluents. In this study, the important physicochemical parameters including pH, total dissolved solids (TDS), electrical conductivity (EC), biological oxygen demand (BOD) and chemical oxygen demand (COD) of the raw water used and the effluents generated were analyzed. The physicochemical parameters of the effluent samples were compared with those of the raw water (bore well) samples to analyze the pollution load of the effluents. The values of the studied physicochemical parameters were much higher than the permissible limits as prescribed by CPCB and WHO. Higher values of pH, TDS, BOD and COD have detrimental health effects on both humans and aquatic life. Direct disposal of the untreated industrial effluents into the water bodies is very hazardous for both biotic and abiotic components of the environment. Therefore proper remedial measures are to be taken for the treatment of effluents before their discharge into the water bodies.

MgO nanopowders were synthesised via a simple and " greener " route using Carica papaya leaf extract at 500 • C. The bio-derived MgO nanopowders (MgONPs) were characterised by Brunauer–Emmett–Teller (BET), differential thermal and thermogravimetric (DTA-TGA) analysis, powder X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS). The COD and BOD reduction efficiency of the MgO—NPs was evaluated in the presence of raw and simulated tannery wastewater. Under optimum conditions, the COD of raw tannery wastewater reduced from 2725.9 mg/L to 126.5 mg/L and BOD from 1899.5 mg/L to 104.5 mg/L in a batch system. Also, the turbidity was reduced from the initial concentration of 588 NTU to a level of 98 NTU within 120 min. Impressively, 93.5% COD reduction and 96.9% BOD reduction were obtained by the fixed-bed system. The spent MgO was regenerated and reused several times without significant loss of capacity. Hence, the bio-derived MgO nanopowders offered potential benefits for BOD and COD removal from tannery wastewater.

The developing world remains plagued by lack of access to safe drinking water. Although many low-cost methods have been developed to treat contaminated water, low-cost methods for water-quality testing are necessary to determine if these appropriate technologies are needed, effective, and reliable. This paper provides a methodology for the design, development, and technical validation of a low-cost, open-source (OS) water testing platform. A case study is presented where the platform is developed to provide both the colorimetry for biochemical oxygen demand/chemical oxygen demand and nephelometry to measure turbidity using method ISO 7027. This approach resulted in equipment that is as accurate, but costs between 7.5 and 15 times less than current commercially available tools. It is concluded that OS hardware development is a promising solution for the equipment necessary to perform water quality measurements in both developed and developing regions.

The textile and apparel industries in Bangladesh are playing an utmost important role offering tremendous opportunities for the economy of Bangladesh. But, hasty and unplanned clustered growth of industries leads to adverse environmental consequence in an alarming way. This work is aimed at giving emphasis on the present pollution scenario in Bangladesh due to textile effluent. The liquid effluents from industries are causing major havoc to the environment, ecology, agriculture, aquaculture and public health since the development of textile industries in the country. In this paper, effluent characterization results of last ten years (2005-2014) are focused. We found physicochemical parameters of Textile effluents in Bangladesh as, Temperature (25-65°C), pH (3.9-14), TDS (90.7 – 5980 mg/L), DO (0-7 mg/L), COD (41 -2430 mg/L), BOD (10 – 786 mg/L), TSS (24.9 – 3950 mg/L) and EC (250-63750μS/cm) from 2005 to 2014. From the available data originated from the study depicts the present pollution scenario in Bangladesh with tremendous violation of laws to meet requirement of waste discharge quality standards. Now it has become a prerequisite to set up ETP in each industrial establishment, particularly at dyeing industries that were discharging huge amount of liquid waste to the rivers every day.

Mulch: Amulchisa layer of material applied to the surface of soil. Reasons for applying mulch include conservation of soil moisture, improving fertility and health of the soil, reducing weed growth, and enhancing the visual appeal of the area. Amulchisusually,butnotexclusively,organic in nature. It may be permanent (e.g., plastic
sheeting) or temporary (e.g., bark chips). It may be applied to bare soil or around existing plants. Mulches of manure or compost will be incorporated naturally into the soil by the activity of worms and other organisms. The process is used both in commercial crop production and in gardening and, when applied correctly, can dramatically improve soil productivity. As the population in tertiary education is continuing to grow, this has increased the demand for food, thus adding pressure to the food supply system. At the same time, food producers are experiencing great competition for land, water, and energy (Godfray et al. 2010). Overarching all of these issues is the threat of climate change andconcernsabouthowmitigationandadaptation measures may affect the food system. Agriculture as their mainfood source in higher education institutions relies on water for the survival of crops. However, it is severely affected by frequent droughts which leads to crop failure, hunger, poverty, and pests and disease outbreaks. Identifying ways to mitigate drought and stabilize yields by encouraging smallholder farmers to adopt best management practices is fundamental to realizing food security and improved livelihoods (Shen et al. 2012; Bhardwaj 2013).

Purpose of the study: Treatment of the wastewater coming from households,  laboratories,  big  AC plants etc. is very important. For this, the use of low cost activated carbon is highly preferable and eco-friendly making great improvements in the quality of wastewater also. The aim of this study is to clean the wastewater collected from the AirPort Height Campus of Caledonian College of Engineering, by the use of activated carbon in the batch process.
Methodology: Wastewater sample is collected from the Airport height campus of CCE, Oman. It was treated using activated carbon in the batch study, and the quality of water is tested in terms of %  variation in CODin the college laboratory. Time, activated carbon dose, pH, and temperature variation were conducted on 50 ml batch size.
Main  Findings: MaximumCOD removal was  88%  at carbon dose  0.2g,  time  30  min,  pH  5  and temperature  550C.The results obtained from experiments were also analysed by  Langmuir and  Freundlich isotherm. Results show that the process fits well with the Freundlich isotherm because R2 values are higher for the linear relationships.
Applications of this study: The results obtained from the experiments clearly indicate that the quality of the treated water has improved and some more parameters that are concerned with the purity factor can be introduced, this water can be made available in form of non-potable usage also. So, this study is highly beneficial for our earth as well as human beings.
Novelty/Originality of this study: The experiment performed very eco-friendly as low cost and easily available chemicals and activated carbon is used here,  so it will relieve us from the expensive and complicated methods for wastewater treatment.

This paper presents a brief account of different technologies used for the treatment of petroleum refinery effluents (PRE). Broadly, PRE treatment is accomplished in two stages, namely, a series of pre-treatment steps, in which suspended matter, oil and grease are reduced, and an advanced stage, in which wastewater contaminants are decreased to certain acceptable discharge limits. Photocatalytic degradation techniques have been widely used in water and wastewater treatment. However, the literature regarding PRE treatment is scarce, and the technique is still not being utilised on an industrial scale in refineries. This is largely due to limited research findings discussing PRE treatments. Most researches are focused on treating singular contaminants found in PRE, e.g., phenols, sulphides, oil, grease and other organic components. This review focused on works that investigated PRE treatment by monitoring general refinery wastewater parameters, namely, chemical oxygen demand (COD), biological oxygen demand (BOD), total petroleum hydrocarbon (TPH), oil and grease (O&G), sulphate and phenols at the advanced treatment steps. This paper presents an overview of photocatalytic degradation and discusses published works with the goal of presenting the technique as an attractive and viable process unit. If optimised, this process has great potential for replacing other separation and degradation treatment approaches employed at the advanced treatment stage for PRE. © 2010 The Institution of Chemical Engineers.

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http://www.sciencedirect.com/science/article/pii/S0957582010001126

Presence of water during biodiesel production and purification processes, storage and use in compression ignition (diesel) engines causes problems that cannot be ignored. These problems include: difficulties in biodiesel processing especially during alkali-catalyzed transesterification process, deterioration of biodiesel quality, decrease in heat of combustion, corrosion of fuel system components, and acceleration of hydrolytic reaction. Beside use of water during biodiesel purification results in wastewater discharges which causes environmental effects, due to high contents of chemical oxygen demand, biological oxygen demand, and higher pH values. Thus, this study critically analyzed and examined the effects of water on biodiesel production and the refining of crude biodiesel. Furthermore the effects of water on the quality of biodiesel were also examined. © 2012 Elsevier Ltd. All rights reserved.

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http://www.sciencedirect.com/science/article/pii/S1364032112001840