The application of magnetic fields for landfill leachate treatment

This research is mainly focused on the capability of magnetic application of 0.55 Tesla magnetic field strength on reduction of suspended solid (SS), BOD5 and COD in landfill leachate through a circulation magnetic device which was conducted using the settling column test. The parameters monitored which effect the reduction of suspended solids and organic concentration were the magnetic exposure time of between 1 hour and 6 hours, operating flow rate of between 1 mL/s and 5 mL/s, and pH of between 2 and 13. Empirical mathematical models of sedimentation and column settling test were investigated to fulfill the behaviour of sedimentation under operating conditions due to the effect of magnetic exposure time, operating flow rate, and pH of the sample. Using the empirical mathematical models were analysed based on total suspended solids (SS), BOD5 and COD removal efficiency to variation of the operating flow rate, magnetic exposure time and pH. The model coefficients were derived from combined analysis of correlated sets of data, thus giving an indication for their possible general applicability. The pH had significant effects on the percentage of SS, BOD5 and COD removal, but pH increased the starting SS, BOD5 and COD removal rate. The study reveals that percentage of SS, BOD5 and COD removal efficiency decreased as the pH below 7 was increased, but it increased as the pH of between 7 and13 was increased the reduction of SS, BOD5 and COD in the sample. The experimental design at an exposure time to magnetic field of 6 hours, a flow rate of 2 mL/s with pH of 13 show that the removal efficiency of SS, BOD5 and COD at 72.57%, 63.93% and 56.97% respectively. Statistically tested by SPSS, there was a significant linear increase in average treatment efficiency to the magnetic exposure time and pH of sample at 95% confidence level. The experimental results were also generated empirical mathematical model relating percentage of SS, BOD5 and COD removal efficiency to flow rate, magnetic exposure time and sample of pH using MINITAB statistical software. The empirical mathematical models can be helpful in designing application of magnetic fields for landfill leachate treatment

Optimization of ceramic waste filter for bathroom greywater treatment using central composite design (CCD)

The present study aims to develop a filtration system consisting of ceramic wastes as a treatment process of bathroom greywater to reduce chemical oxygen demand (COD), Total suspended solids (TSS), Total nitrogen (TN), and turbidity. Optimization of the reduction efficiency was investigated using response surface methodology (RSM) as a function of the ceramic practical sizes (0.25–1.18 mm) and hydraulic retention time HRT (1–3 h). The functional groups on the surface of the ceramic filter media were determined using Fourier transform irradiation (FTIR), while the scanning electron microscope (SEM) was used to determine the microstructure and the surface morphology of the ceramic particles. Results revealed that the optimal reduction of COD, TSS, TN, and turbidity was influenced by active sites of the filter media (C]C, C]O, CeOeH, and OH−) and was achieved under the operating conditions of 0.25 mm of ceramic particles after 3 h of HRT, the observed and predicted reduction for COD, TSS, TN, and Turbidity were 38.8 vs. 39.8%; 58.47 vs. 59.59%; 66.66 vs. 67.32%; 88.31 vs. 89.02%, respectively. It can be concluded that the effectiveness of the ceramic filter media is a potential source for the filtration of bathroom greywater

Economic impacts of changes in fish population dynamics: the role of the fishermen’s harvesting strategies

Using a bioeconomic model of the cod (Gadus morhua) and capelin (Mallotus villosus) fisheries of the Barents Sea, this study assesses the role of the fishermen’s behavior in reducing or intensifying the effects on the stocks caused by altered population dynamics. The analysis focuses on the economic development of the fisheries employing a profit-maximizing harvesting strategy over a given number of fishing periods. The scenarios assessed cover a time period of 100 years with sudden changes of the productivity of both species occurring at the midpoint of each simulation. Stock sizes and landings of fish are determined for each fishing period, and the net present values of profits over periods of interest prior to and following the change in population dynamics are calculated. Results show that if the profit-maximizing harvesting strategy is based on a short optimization period, the fleets with the higher efficiency are generally favored. If the strategy is based on an optimization over two or more fishing periods, fishing activities may be deferred to allow for stock regrowth. In such cases, smaller and less cost-intensive vessels are preferred. A reduction of either the productivity or the carrying capacities of the two species has little impact on the fisheries if the change is fairly small. A substantial reduction of either quantity has a lasting negative economic impact which mainly manifests itself in a severely reduced profitability of mainly the cod fishery.bioeconomic modeling, Barents Sea, cod, capelin, population dynamics, harvesting strategy

Degradasi Bod Dan Cod Pada Sistem Lumpur Aktif Pengolahan Limbah Cair Tekstil

Observation of waste parameter in textile wastewater treatment wasdone. This experimental investigation consist of three mayor textileparameter including total suspended solid (TSS), biological oxygendemand (BOD) and chemical oxygen demand (COD). The parameterswere collected and analyzed. The TSS, BOD and COD consentration ineffluent of textile wastewater treatment is not exceeded the standard,but the efficiency of TSS, BOD and COD reduction is not statisticallysignificant

The COD Reduction of Wastewater Using Oxyl

The main objective of this work was to investigate the effectiveness of oxyl in removing the chemical oxygen demand (COD) from wastewater. Oxyl is a strong oxidizing solution generated by the electrolysis of w = 1 % NaCl brine solution from the well of the positive electrode in an electrolysing apparatus. The electron spin resonance (ESR) spin trap technique showed that several free radical species, with high oxidation potential, are present in oxyl solution. Experimental oxidations of industrial wastewater polluted by surfactants were performed using oxyl (in the laboratory) and industrial scale yielding a COD reduction of up to 70 %. The implementation of wastewater treatment using oxyl in an industrial plant may considerably reduce the water pollution tax that companies are paying for wastewater discharge. An economic feasibility study of the investment was performed, which indicated the good economic potential of the procedure

Treatment of Paper Wastewater Using Combination of Coagulation Flocculation and Membrane Methods

The previous research has been conducted to find out the potential of non-wood fibers as an alternative for paper-making raw material. The non-wood fibers used are combination of rice straw and used paper. It was processed by using soda pulping method.The paper waste contains dissolved lignin component and other organic compounds in high pH condition can produce wastewater with high chemical oxygen demand(COD). In this research pulp or paper wastewater wast treated through combination of coagulation flocculation and membrane method to achieve a permitted level of COD. It was also determined the optimal condition which can reduce the COD value to fulfill the requirement for water disposal.The initial conditions of paper wastewatear are pH: 14, COD in the range of 3,000 - 11,000 ppm. The coagulation-flocculation process was conducted by using Poly Aluminium Chloride( PAC) as coagulant and anionic flocculant. The experiment is conducted by two steps. firstly determined the optimum coagulation flocculation (coagulant dose)for soluble organic material removal and then followed by micro-or ultrafiltration process. To produce asymmetric asymmetric membrane for filtration process. it was synthesized cellulose acetate membrane through phase inversion technique. The pore size of the membrane was modified by varying the composition of cellulose acetate in the range of 15-18 % w/w. The COD value of wastewater was analyzed before and after treatment to find out the effectivity of coagulation and the membrane process by studying its flux and rejection.The result showed that COD reduction less than 200 ppm can be reached through the treatment of combination of coagulation - flocculation and micro-or ultrafiltration process. The result also indicated that with initial COD 6,063 ppm. 10.000 ppm of coagulant, 1 ppm of flocculant and l8% w/w of cellulose acetate membrane. COD can be reduced up to 96.87

Baltic cod reproduction in the Gotland Basin: annual variability and possible causes

Baltic cod spawning takes place in the deep basins and reproduction success is mainly related to environmental conditions (salinity and oxygen regimes, i.e. the 'reproduction volume'). Due to the Baltic Sea heterogeneity, cod reproduction success in the Southem and Centrat Baltic spawning grounds can differ significantly. Recent oceanographic changes i.e. decrease of water exchange and stagnation, as weil as a strong reduction of spawning stock caused the diminishing of the reproduction potential of the Gotland spawning grounds. The Gotland spawning grounds belong to four main cod spawning sites in the Baltic and historical analyses revealed that abundant generations of Baltic cod were produced when successful cod reproduction took place also in the Gotland Basin. Analyses of revised reproduction volume estimates for the Gotland Basin taking into account the spatial structure of hydrology in the basin during stagnation and aeration periods reveals high seasonal and inter-annual variability. To describe changes of abundance and distribution of the spawning stock and the recruits in relation to hydrographic conditions, results from trawl surveys carried out in 1975-1998 in the Gotland Deep are analyzed. In this analysis, the reproduction volume is used as a proxy for the environmental conditions

Electrochemical Reduction Prior to Electro-Fenton Oxidation of Azo Dyes : Impact of the Pretreatment on Biodegradability.

International audienceThe aim of this work was to study the degradation of three azo dyes, Orange II, Methyl red and Biebrich Scarlet by electro-Fenton and the effect of the electrochemical pretreatment on the biodegradability of the solutions. The electrochemical pretreatment showed that an electrochemical reduction on the carbon felt electrode was mainly responsible for the decolorization of the azo dyes. Indeed, the electrochemical behaviour of the azo dyes highlighted their electroactivity; electrolysiswith and without ferric ions led to the same decolorization yield, namely 99 % at 15 min for Methyl red, and stable chemical oxygen demand (COD) values were recorded during decolorization. In a second step and owing to the absence of by-product electroactivity in reduction, the formation of hydroxyl radicals by the Fenton reaction led to the oxidation of by-products from the electrochemical reduction. It was illustrated by the decrease recorded for the COD values. The results also showed that the azo bond cleavage occurring during the electrochemical reduction was not sufficient to significantly reduce recalcitrance, as shown from biological oxygen demand (BOD)(5)/COD ratio examination below the limit of biodegradability (0.4). Contrarily, a positive trend was recorded for Orange II during the electro-Fenton reaction, with a BOD5/COD ratio of 0.81 after 28 h of pretreatment

Improvement of Bod5/Cod Ratio Inpre-Treated Distillery Waste Water by Electrochemical Treatment Method

Electrochemical oxidation of low (BOD5/COD) ratio post-methanation distillery wastewater was investigated. The effects of operating parameters like pH, electrolysis duration and current density on COD removal were studied. At a current density of 0.03 Ampere/cm2 and at pH 3 the COD removal was found to be 72%. The BOD5/COD ratio of pretreated distillery wastewater was 0.145 and increased to 0.686 for an optimum of 120 minutes electrolysis duration indicating improvement of biodegradability of wastewater. The TOC reduction is 8.77% at 180 minutes of electrolysis duration. The maximum anodic efficiency observed was 21.58 kg COD h-1A-1m-2 and the minimum energy consumption observed was 84.16 wh kg-1 COD. The kinetic study reveals that reaction rate (k) decreases with increase in pH and increases with increase in current density