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The purpose of this paper is to evaluate the possibility of a new biocatalyst prepared by kefir cells immobilization on grape stalks (GS) to reduce quickly and efficiently the Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) of the waste whey during its fermentation producing potable ethanol.

Many batch whey fermentations were carried out in order the effect of various conditions (pH, temperature) on 14C-labeled lactose uptake rate by the GS-immobilized kefir cells and consequently on fermentation rate as well as on ethanol production and whey BOD and COD reduction to be determined.

It has been illustrated that GS-biocatalyst was suitable for whey BOD and COD reduction by about 32 and 25 percent, respectively during whey alcoholic fermentation at 30°C and pH 5.5 in only ten hours, producing about 3.30 percent w/v of ethanol.

The findings of this research may enhance the existing literature on whey exploitation, for the first time focussing on the use of cheap and abundant GS as support for kefir immobilization during whey fermentation, which is potentially acceptable by industries in order to reduce fast and easily the whey polluting load and produce ethanol.

This paper aims to select a type of mordant from aluminium salts, namely, aluminium sulphate, aluminium nitrate and polyaluminium chloride (PAC) with the lowest potential for contamination so that their use will minimise pollution from natural dye waste. It also aims to determine the pollution value of natural dye immersion waste from jackfruit wood extract, secang wood, mangsi fruit and several synthetic dyes, to identify potential environmental pollution.

Dyeing with natural dyes was performed by exhaust at room temperature by the pre-mordant method, while with synthetic dyes it was performed by exhaust according to the dyeing procedure (reactive, vat and naphthol). The groundwater, mordant solutions, natural dye extract and the waste-water from the natural and synthetic dyes were then tested to determine their biological oxygen demand (BOD₅), chemical oxygen demand (COD), total suspended solids (TSS), pH, Al and heavy metal contents such as chromium (Cr), copper (Cu), cadmium (Cd), nickel (Ni), cobalt (Co) and lead (Pb).

Aluminium sulphate had the lowest pollution load while PAC had the highest, as aluminium sulphate had a higher BOD₅/COD ratio (0.62–0.67) than aluminium nitrate (0.56–0.64) or PAC (0.44–0.54). The dyeing waste from the three natural dyes contained an acidic pH of 3.5–4.2, Al of 75.280–621.34 mg/L, Cr of 0.154–0.215 mg/L and Cu of 0.035–0.072 mg/L. The values of TSS, COD and BOD₅ are higher than the quality standards of the waste but are environmentally friendly because the ratio of the BOD₅/COD values from the waste ranges from 0.44–0.67.

The findings indicate that as a mordant, aluminium sulphate results in lower pollution loads than aluminium nitrate and PAC. However, all three mordants contain Cr and Cu, albeit in negligible concentrations. Therefore, it is recommended that future studies strive to identify a mordant that has lower pollution loads and does not contain metals but can increase dyeing results to satisfy consumer requirements. It is the hope that, with the discovery of a new mordant, natural dyes will be the solution for the heavy metal pollution caused by synthetic dyes.

The use of environmentally-friendly mordants and natural dyes in the Indonesian textile and batik industry will give rise to superior quality eco-textile and eco-batik products. Such environmentally-friendly and high-quality products will not only increase competition and consumer interest but increase product sales as well which will, in turn, increase incomes and the economy. Additionally, an increase in the use of natural dyes by the textile and batik industry will serve as additional income to the communities and farmers from which the raw materials for the natural dyes are sourced thereby creating jobs and increasing welfare.

As environmentally-friendly mordants and natural dyes replace the hazardous and toxic materials currently used in the textile and batik industry, it guarantees the health and safety of its consumers and workers. Furthermore, as the waste-water produced is biodegradable, it reduces river and groundwater pollution. It is, therefore, expected that this information will not only lead to a shift in attitude within the textile and batik industries but the adoption of environmentally-friendly materials, for the sake of the environment, as well as the development of eco-textile and eco-batik products.

Aluminium sulphate is a mordant type of aluminium salt with a lower potential for contamination than aluminium nitrate and PAC. However, PAC has been discovered to be a mordant for natural dyes, as has the fruit of the mangsi shrub, which has recently been discovered as a naturally occurring blue dye.

The purpose of this paper is to propose a methodology that may aid in assessing ecological quality multi‐trait screening through the use of simple and robust tools while exerting minimal effort in conducting trials and interpreting results.

Response data for two popular site‐monitoring environmental indicators, chemical oxygen demand (COD) and biochemical oxygen demand (BOD), are arranged by implementing an 8‐run saturated orthogonal array proposed by Taguchi. Unreplicated data consolidation is performed through the Super‐Ranking translation. This permits converting the two eco‐traits to a single master response which becomes much easier to manipulate statistically. Distribution‐free multi‐factor contrasting provides the data reduction engine to filter‐out non‐active eco‐design variables for a waste treatment unit in a large dairy‐products plant.

Environmental quality improvement is achieved by accumulating structured eco‐data sets through an unreplicated‐saturated L₈(2⁷) Taguchi design. Concurrent minimization of the two selected eco‐responses, COD and BOD, promotes in a statistically significant fashion the quantity of incoming wastes, set at its minimum load, as the sole active eco‐factor.

Brief but robust experimentation is exploited in gaining information about the phenomenological behavior of environmental quality indicators, namely COD and BOD, in facilities that manage wastewater treatment. Design for environment is enforced through standard DOE planning schemes. Collected multi‐metric eco‐quality data are translated non‐parametrically in an easy‐to‐comprehend manner that requires no assist from software aids while bypassing more statistical intensive techniques which may demand involvement of more experienced personnel. The methodology is accessible to any level of statistical competence seamlessly intertwined to optimization demands for rapid inference needs.

The method mixes up three distinctive “design‐and‐analysis” elements in order to provide optimal solution in a design‐for‐environment project. The sampling capabilities of Taguchi's orthogonal arrays in concert with Super‐Ranking transformation fuse multi‐eco‐characteristics to a single easy‐to‐handle master unitless eco‐response. Order statistics tables recently published in terms of true probabilities have been adopted for supplying the proper cutoff points to be utilized for gauging against observed rank sums for an 8‐run orthogonal array screening. Quality managers and environmental engineers who contribute routinely to continuous eco‐improvement projects in their Total Environmental Quality Management (TEQM) program may find this approach attractive and viable en route to a typical industrial pollution prevention control deployment.

The purpose of this paper is to evaluate the efficiency of a duckweed pond in the polishing of a stabilization pond effluent, as well as quantify its biomass production. Once an adequate destination is given to the produced biomass, the wastewater treatment plant can work in a sustainable and integrated way.

The duckweed pond consisted of a tank with volume 0.44 m³, operating in continuous flow with an outflow of 0.12 m³/day and hydraulic retention time of 3.8 days. Effluent samples were collected before and after the treatment, with analyzes made: daily-pH, dissolved oxygen and temperature; twice a week – total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD); and weekly – total solids (TS) and Biochemical Oxygen Demand (BOD₅). The duckweeds were collected each for seven days for its production quantification.

The highest efficiency of TN, TP, COD, BOD₅ and TS removal were of 74.67, 66.18, 88.12, 91.14 and 48.9 percent, respectively. The highest biomass production rate was 10.33 g/m²/day in dry mass.

There was great variation in biomass production, which may be related to the stabilization pond effluent conditions. The evaluation of the effluent composition, which will be treated with duckweeds, is recommended.

The evaluated treatment system obtained positive results for the reduction in the analyzed variables concentration, being an efficient technology and with operational simplicity for the domestic effluent polishing.

The motivation of this work was to bring a simple system of treatment and to give value to a domestic wastewater treatment system in a way that, at the same time the effluent polluter level is reduced and it is also possible to produce biomass during the treatment process.

Pre‐treatment of wastewater discharged from a potato‐chips factory was the subject of this study. Wastewater discharged from this factory is characterized by high values of BOD, TSS and oil and grease (3,685, 4,115 and 169mg/l, respectively). Treatability studies via continuous aerobic and anaerobic methods treatment have been investigated. The results obtained showed marked improvement in the quality of the treated effluent using packing material versus the upflow anaerobic sludge bed reactor (UASB) without packing. An extra removal in COD (53 per cent), BOD (61 percent), TSS (52 per cent) and oil and grease (46 per cent) was obtained. Corresponding residual values were 398mgO₂/l, 235mgO₂/l, 108mg/l and 38mg/l, respectively. Based on the laboratory results, engineering designs and economic evaluation of the different treatment systems were developed.

This paper aims to evaluate the performance of the Mashhad No. 5 wastewater treatment plant (WWTP) using a combination of data mining (regression) algorithms and artificial neural networks.

In this research, the performance of WWTP located in Mashhad, Iran, has been evaluated using two data mining models, neural network and regression model.

The proposed model has the potential of implementing in other WWTPs in Iran or other countries.

The authors would also like to thank Mashhad No.5 WWTP for data access.

In this study, the oxidative degradation performance of indigo wastewater based on electrochemical systems was explored. The decolourization degrees, removal rate of chemical oxygen demand and biochemical oxygen demand of the indigo wastewater after degradation were evaluated and optimized treatment conditions being obtained.

The single factor method was first used to select the electrolyte system and electrode materials. Then the response surface analysis based on Box–Behnken Design was chosen to determine the influence of four independent variables such as FeCl₃ concentration, NaCl concentration, decolourization time and voltage on the degradation efficiency.

On the basis of single factor experiment, the electrode material of stainless steel was selected in the double cell, and the indigo wastewater was electrolyzed with FeCl₃ and NaCl electrolytes. The process conditions of electrochemical degradation of indigo wastewater were optimized by response surface analysis: the concentration of FeCl₃ and NaCl was of 16 and 9 g/L, respectively, with a decolourization time of 50 min, voltage of 10 V and decolourization percentage of 98.94. The maximum removal rate of chemical oxygen demand reached 75.46 per cent. The highest ratio of B/C was 3.77, which was considered to be more biodegradable.

Dyeing wastewater is bringing out more and more pollution problems to the environment. However, there are some shortcomings in traditional technologies such as adsorption and filtration. As a kind of efficient and clean water treatment technology, electrochemical oxidation has been applied to the treatments of various types of wastewater. The decolourization and degradation of indigo wastewater is taken as an example to provide reference for the treatment of wastewater in actual plants.

The developed method provided a simple and practical solution for efficiently degrading indigo wastewater.

The method for the electrochemical oxidation technology was novel and could find numerous applications in the degradation of printing and dyeing wastewater.

The purpose of this paper is to assess the water quality parameters resulting on: First, the flow direction in biofilters (ascending or descending), second, constructed wetland (CW) with local plant species and third, the combined system for the removal of organic matter and nutrients pollutants from water in arid regions.

An integrated system is presented and tested in situ with a vertical up-flow and down-flow biofilters. Two configurations schemes are followed by a three separated horizontal subsurface CWs: two planted with Phragmites australis, Typha latifolia and the third unplanted. The methodology is based on a statistical analysis of the collected data.

The present experiment demonstrated that the wetlands planted with P. australis and T. latifolia showed the highest removal. Moreover, T. latifolia performed better than P. australis for most of the parameters, notably in the first system, whereas the wetland efficiency indicated that P. australis contributed greatly to the removal of TP in the first system and NO₃-N in the second system. In general, for the highest removal efficiencies of the combined biofilters and wetlands system, the present study demonstrated that the first system performed better than the second for all the parameters.

The originality of the research is that it compares in situ two biofilter systems: vertical up-flow and down-flow biofilters. To avoid the effects of domestic wastewater that is discharged directly without treatment in the Oued Righ channel or in the lake, this integrated system can be one of the alternatives for wastewater treatment, as it reveals the need to protect aquatic ecosystems in arid regions, and can decrease the risks to human health and the environment.

Examines the treatability of highly polluted wastewater from a dairy factory prior to its final disposal into the public sewerage system. Physical treatment of the dairy waste via aeration, followed by settling, resulted in a 25 per cent chemical oxygen demand (COD) reduction and elimination of odours. Chemical treatment achieved almost 50 per cent removal of COD. The chemical‐biological process using activated sludge/trickling filter resulted in 64 per cent and 90 per cent removal of the volatile organic matter value respectively. However, the quality of the waste produced does not meet with the National Regulatory Standards for wastewater disposal into the sewerage system. Chemical‐biological treatment using an upflow anaerobic reactor succeeded in reducing the pollutional parameters to coincide with the limits of the Egyptian Law 93/1962 and produces biogas as a source of energy at a rate of 0.39m³/kg COD removed.

A study was designed to investigate the chemical coagulation process for the treatment of the potato food industry wastewater of the “Chipsy factory” located at Abi‐Sier, Egypt. The chemical coagulants used in the study include alum, ferric chloride, calcium chloride, ferric sulphate and Nalco as polymer. Variable doses of these coagulants were examined to determine the optimum dose. Results obtained showed that chemical treatment (coagulation, flocculation, followed by sedimentation) was efficient to reduce the chemical oxygen demand (COD), total suspended solids (TSS) and turbidity significantly. Remarkable variation of the removal efficiency depends on the type of coagulant. Ferric chloride and ferric sulphate were more efficient than calcium chloride. Combination of Nalco with each of the studied coagulants improved the removal efficiency remarkably. Reduction of 91‐94 per cent of turbidity, 93‐97 per cent of COD, and 94‐97 per cent of the TSS was achieved with these combinations.