Reduction Of TDS Research Articles

Bio-electro catalytic treatment of petroleum produced water: Influence of cathode potential upliftment

Treatment of petroleum produced water (PPW) was studied using bioelectrochemical system (BES) under uplifted cathode potential. The treatment efficiency in terms of COD and hydrocarbon removal was observed at 91.25% and 76.60% respectively, along with the reduction in TDS during BES operation under 400mV of cathode potential. There was also a reduction in concentration of sulfates, however, it was not significant at, since oxidative conditions are being maintained at anode. Improved oxidation of PPW at anode also resulted in good power output (−20.47mA) and also depicted improved fuel cell behaviour. The electrochemical analysis in terms of cyclic/linear sweep voltammetry also showed well correlation with the observed treatment efficiencies. The microbial dynamics of the BES after loading real field wastewater showed the dominance of species that are reported to be effective for petroleum crude oil degradation.

Bioremediation Potential of Bacterial Isolates for Municipal Wastewater Treatment

The potential of bacteria for the treatment of municipal wastewater was investigated in present study. Total eight bacterial isolates were used for this study that showed growth on wastewater agar medium. These isolates were identified on the basis of morphological and biochemical test and identified as Bacillus licheniformis NW16, Pseudomonas aeruginosa NS19, Pseudomonas sp. NS20, Planococcus salinarum NS23, Stenotrophomonas maltophilia NS21, Paenibacillus sp. NW9, Paenibacillus borealis NS3 and Aeromonas hydrophilia NS17. The B. licheniformis NW16 showed highest potential to reduce all parameter under study than other isolates except Ammonical nitrogen. B. licheniformis NW16 and Aeromonas hydrophilia NS17 showed maximum reduction (42.86%) in BOD each. B. licheniformis NW16 and Paenibacillus sp. NW9 showed 82.76% and 81.61% reduction in COD respectively. B. licheniformis NW16, P. salinarum NS23 and Aeromonas hydrophilia NS17 showed reduction in nitrate ranging from 17.36%-63.64%. All the isolates have potential to reduced phosphate from 17.55% -72.3%. B. licheniformis NW16, Ps. aeruginosa NS19, Pseudomonas sp. NS20, Paenibacillus sp. NW9 and Aeromonas hydrophilia NS17 showed reduction in TSS ranging from 42.69%-79.94%. B. licheniformis NW16, Ps. aeruginosa NS19, Pseudomonas sp. NS20, S. maltophilia NS21 and Paenibacillus sp. NW9 showed reduction in TDS ranging from 14%-81.4%.

Ammonia Behaviour in Wastewater Reclamation by Soil Aquifer Treatment

Groundwater use is increasing all over India and Chennai is not an exception. A good possibility exists to recharge artificially the excess treated wastewater through Soil Aquifer Treatment (SAT) and use the recharged water for purposes other than drinking. Soil column experiments were performed, in order to study the ammonia, nitrite and nitrate reduction from Real Secondary Treated Wastewater (RWW). SAT was simulated in four 15 cm long soil columns packed with soils of Sandy Clay Loam (SCL) texture collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Soil Columns were ponded with wastewater to a depth of 2.5 cm above the soil surface and operated for a period of Ten cycles under 4 different alternating wet and dry cycles, 0.25 day wet/1.75 days dry (R1), 0.25 day wet/2.75 days dry (R2), 0.25 day wet/3.75 days dry (R3) and 0.25 day wet/7.75 days dry (R4). The effect of wetting and drying periods on SAT ammonia removal performance was assessed comparing ammonia, nitrite, nitrate nitrogen and TDS rates. The removal of ammonia was through nitrification process which is found to be a dominant removal mechanism of nitrogen. Nitrification differed according to the different drying cycle’s time with fixed flooding period. When the reduction performance achieved with different drying cycles were compared, it could be seen that longer drying periods with R3 column yielded with the least nitrate value of 0.58 mg/l. From this study, it was found that with the fixed wetting period, maximum drying period is required for nitrate reduction and minimum drying period is required for TDS reduction.

Performance characteristics of surfactant treated commercial polyamide membrane in the nanofiltration of model solution of reactive yellow 160

Top surface modification of commercial PA-NF 150 membrane was carried out by dip-soaking the membrane swatches with predetermined concentration of aqueous solutions of sodium dodecyl sulphonate (SDS), cetyltrimethylammonium bromide (CTAB) and Triton X-100 as anionic, cationic and non-ionic surfactants, respectively. The modified flat sheet membranes were used in the nanofiltration of the Reactive yellow 160 dye waste water in a pilot plant. AFM, FTIR-ATR, and water contact angle measurements were employed to characterize the prepared membranes. Addition of surfactants resulted in membranes with superior dye rejection in comparison to untreated membranes. The percent rejection of dye was in the vicinity of 95% for both CTAB and SDS treated membranes, however the results were different for Triton X-100. CTAB treated PA-NF membrane was observed to have marginally less extent of volumetric flux reduction with time compared to other two surfactant treated membranes. Substantial removal of color was achieved in the nanofiltration experiments with a marked reduction in COD and TDS. The process allowed the production of permeate stream with great reutilization possibilities.

Effluent Treatment for Sago Industry Using Zeolite and Activated Carbon

Sago industry is an important component of small scale sector in the developing countries of the tropical region, like India. Being small scale industries, they suffer a lot to overcome the menace of treating the high strength effluent, from the sago processing, containing a large amount of organic material which has a potential to cause high level of water pollution in the surrounding environment. With an objective to minimise the effects of water pollution from the sago industries, we took up a study to increase the efficiency of effluent treatment, by using a complex filter comprising activated carbon and zeolite. The study shows that this method can prove to be an improvement over other methods by enhancing the efficiency of the pollutant reduction process in the sago effluent treatment as the result has shown considerable reduction in TDS, BOD5 and COD of the effluent.

EFFECT OF SILICON ON CALCIUM, PROLINE, GROWTH RATE AND SALT STRESS OF NARROW-LEAVED CATTAILS IN SYNTHETIC REACTIVE DYE WASTEWATER

Narrow-leaved cattails (Typha angustifolia L.) show higher efficiency in the removal of colour and reduction of pH, TDS, and conductivity from synthetic reactive red dye wastewater (Rw) when silicon is added to the wastewater. The efficiency of the colour removal was increased from 86% within 12 days to 93% within 9 days with the addition of silicon. Furthermore, the TDS was also decreased when adding silicon in the wastewater. In addition, calcium and proline accumulation in the plant leaf increased in response to increasing Rw concentrations in the absence of added silicon. Higher salinity was also observed with increasing Rw concentrations. Plants attempt to balance their water potential by secreting proline as an osmotic adjustment. But both calcium and proline levels decreased when silicon was added to the wastewater. This result implies that the plant uses silicon as primary element for responsibility under salt stress condition by increasing growth of plant. In addition, silicon can be used instead of calcium, resulting in decreased proline and calcium production in the plant.

Hydrogeo-chemical impacts of air sparging remediation on a semi-confined aquifer: Evidences from field monitoring and modeling

Air sparging (AS) was explored for remediation of a petroleum contaminated semi-confined groundwater system in NE China. Physical, hydro-chemical and hydraulic behaviors in subsurface environment during AS were investigated with support of modeling to understand the hydrogeo-chemical impacts of AS on the aquifer. The responses of groundwater, dissolved oxygen and temperature indicated that the radius of influence of AS was up to 8–9m, and a 3D boundary of the zone of influence (ZOI) was accordingly obtained with volume of 362m3. Water mounding unlike normal observations was featured by continuous up-lift and blocked dissipation. AS induced water displacement was calculated showing no obvious spreading of contaminant plume under this AS condition. Slug tests were employed before and after AS to reveal that the physical perturbation led to sharp increase in permeability and porosity. Modeling indicated that the regional groundwater flow field was not affected by AS except the physical perturbation in ZOI. Hydro-chemically increase of pH and Eh, and reduction of TDS, electrical conductivity and bicarbonate were observed in ZOI during AS. PHREEQC modeling inferred that these chemical phenomena were induced by the inorganic carbon transfer during air mixing.

Analysis of the Spatio-Temporal Patterns of Water Pollution and Source Contribution Using the MODIS Sensor Products and Multivariate Statistical Techniques

Analysis of the spatio-temporal patterns and source apportionment of water pollution is important for proper management and protection of water resources. In this paper, different multivariate statistical methods were used to explore the spatio-temporal patterns of water pollution, and quantitative relationships between the important pollution parameters and environmental variables. Eleven significant parameters measured in 22 monitoring sites were preprocessed spanning between 2001 and 2007. Results of the hierarchical clustering analysis (HCA) demonstrated that this method had high flexibility for efficient classification of the monitoring sites. Results of discriminant analysis (DA) revealed that a high number of parameters contributed in discrimination of classes in the spring and summer seasons, especially in the April and September months. Recorded data of river water temperature (RWT), runoff, and two products of the MODIS sensor including the monthly Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) for the period of 2002-2007 were used as the explanatory variables. Test of NDVI and LST was based on extraction of their average values in different buffers of 250 up to 1500 m around the streams. Monthly data of group 1, a group with the highest number of monitoring sites resulting from the clustering procedure, was used for the analysis. Rotated principal component analysis (rotated PCA) was used for exploration of the quantitative relationships between the pollution parameters and environmental variables. Absolute principal component score- multivariate linear regression (APCS-MLR) was applied to quantify the source contributions for each pollution parameter. Results showed that NDVI and runoff can be considered as the efficient indicators of the non-point pollution sources such as the agricultural activities and surface weathering. NDVI showed an important role in reduction of TDS and No3-. Multiple buffers of NDVI showed temporally variable relations with different pollution sources. LST showed high discrimination potentials for distinguishing pollutions related to biochemical activities. Although the tested environmental variables revealed some relationships with those of the water pollution sources, nevertheless for more detailed analysis of the water pollution problem, the role of other latent environmental variables should be taken into consideration.

Application of reverse osmosis membrane system for treatment of effluent in textile knitted fabric dyeing

The world’s water is found in oceans, seas, lakes, reservoirs, rivers and streams, glaciers and snowcaps in the Polar Regions, in addition to ground water below the land areas. The water locked up in the oceans and seas are too salty and cannot be used directly for human consumption, that is, for domestic, agricultural or industrial purposes. The textile industry consumes a vast quantity of water and generates an equally vast quantity of waste water. This work mainly focused on the treatment of wastewater from the textile knitted fabric dyeing industry. The membrane selection process was theoretically designed using well known design software, like KOCH and ROSA. To design the treatment plant system based on the analytical report and software membrane, reverse osmosis (RO) system was used. To compare the experimental and theoretical (KOCH and ROSA software) values for the characteristics of knitted fabric dyeing effluent, the results revealed that the KOCH software membrane shows more recovery, high TDS reduction, less power consumption and low investment cost than ROSA type membrane in the treatment of effluent from knitted fabric dyeing. Key words: KOCH and ROSA software membrane, knitted fabric dyeing, reverse osmosis, textile effluent, water treatment.

Application of reverse osmosis membrane system for treatment of effluent in textile knitted fabric dyeing

The world’s water is found in oceans, seas, lakes, reservoirs, rivers and streams, glaciers and snowcaps in the Polar Regions, in addition to ground water below the land areas. The water locked up in the oceans and seas are too salty and cannot be used directly for human consumption, that is, for domestic, agricultural or industrial purposes. The textile industry consumes a vast quantity of water and generates an equally vast quantity of waste water. This work mainly focused on the treatment of wastewater from the textile knitted fabric dyeing industry. The membrane selection process was theoretically designed using well known design software, like KOCH and ROSA. To design the treatment plant system based on the analytical report and software membrane, reverse osmosis (RO) system was used. To compare the experimental and theoretical (KOCH and ROSA software) values for the characteristics of knitted fabric dyeing effluent, the results revealed that the KOCH software membrane shows more recovery, high TDS reduction, less power consumption and low investment cost than ROSA type membrane in the treatment of effluent from knitted fabric dyeing. Key words : KOCH and ROSA software membrane, knitted fabric dyeing, reverse osmosis, textile effluent, water treatment.

A novel extracellular protease from Pseudomonas aeruginosa MCM B-327: enzyme production and its partial characterization

The focus of this study was on production, purification and characterization of dehairing protease from Pseudomonas aeruginosa MCM B-327, isolated from vermicompost pit soil. Optimum protease activity, 395 U mL(-1), was observed in the medium containing soybean meal and tryptone, at pH 7 and 30 °C. The crude enzyme exhibited dehairing activity. As compared to chemical method, enzymatic method of dehairing showed reduction in COD, TDS and TSS by 34.28%, 37.32% and 51.58%, respectively. Zymogram of crude enzyme on native-PAGE presented two bands with protease activity of molecular weights of 56 and 67 kDa. Both proteases showed dehairing activity. Out of these, 56kDa protease (PA02) was purified 3.05-folds with 2.71% recovery. The enzyme was active in pH range 7-9 and temperature 20-50 °C with optimum pH of 8 and temperature 35°C. Moreover, the enzyme activity of PA02 protease was not strongly inhibited by specific inhibitor showing the novel nature of enzyme compared to serine, cysteine, aspartyl and metalloproteases. Kinetic studies indicated that substrate specificity of PA02 protease was towards various natural and synthetic proteolytic substrates but inactive against collagen and keratin. These findings suggest protease secreted by P. aeruginosa MCM B-327 may have application in dehairing for environment-friendly leather processing.

Optimization of a novel enzyme treatment process for early-stage processing of sheepskins

An enzyme treatment process for early-stage processing of sheepskins has been previously reported by the Leather and Shoe Research Association of New Zealand (LASRA) as an alternative to current industry operations. The newly developed process had marked benefits over conventional processing in terms of a lowered energy usage (73%), processing time (47%) as well as water use (49%), but had been developed as a "proof of principle''. The objective of this work was to develop the process further to a stage ready for adoption by industry. Mass balancing was used to investigate potential modifications for the process based on the understanding developed from a detailed analysis of preliminary design trials. Results showed that a configuration utilising a 2 stage counter-current system for the washing stages and segregation and recycling of enzyme float prior to dilution in the neutralization stage was a significant improvement. Benefits over conventional processing include a reduction of residual TDS by 50% at the washing stages and 70% savings on water use overall. Benefits over the un-optimized LASRA process are reduction of solids in product after enzyme treatment and neutralization stages by 30%, additional water savings of 21%, as well as 10% savings of enzyme usage.

Treatment of Textile Wastewater with Chlorine: An Effective Method

As the chlorination of textile wastewater achieves all the objectives of its treatment such as color removal and reduction of TDS, BOD and COD; and the treated effluents meet the standards set as per Schedule 12-B of the Environment Conservation Rules-1997 (ECR-97, Bangladesh), the treatment of textile wastewater with chlorine gas is a practical technological option for Bangladesh. If this process which is simple if adopted by the textile sector, the ETP operation would be widely practised for its low operating costs because of low price of chlorine produced by local chlor-alkali plants in the country. Satisfactory operation of the ETPs treating textile wastewater with chlorine at low costs has made this process affordable and attractive to the textile sector. Some of the perceived limitations of chlorination outweighs the greater benefits of textile wastewater treatment with chlorine gas leading to cleaner water bodies which receive these effluents otherwise.Keywords:Textile wastewater, chlorination, ETP, wastewater treatmentDOI = 10.3329/cerb.v14i1.3206 Chemical Engineering Research Bulletin 14 (2010) 59-63 

REUSE OF REFINERY TREATED WASTEWATER IN COOLING TOWERS

In this report, experimental investigation of waste water treatment by reverse osmosis to enable its reuse in cooling tower is presented. A polyamide spiral wound RO membrane followed by three filters as RO pretreatment (two activated carbon and one cartridge filter) and samples of Tehran refinery treated waste water have been used. The effect of operating conditions such as pressure difference, temperature and feed concentration on permeation flux, permeate concentration and fouling have been studied. The results show that continuous operation with a pressure difference of 6 bar and a temperature of 30 °C are the best operating conditions. Analysis of the water treated by RO represents 95 %, 100 %, 93 % and 97 % reduction in TDS, TH, Cl - and SiO2, respectively. Comparison between the treated wastewater analysis and city water used in cooling tower as make up water shows the suitability of reverse osmosis method for the above mentioned purpose.

Effluent COD Reduction via Gas Hydrate Freezing and Its Modeling

Over the past decades, the pulp and paper industry has made considerable efforts to reduce fresh water usage and minimize effluent discharges. Several effluent free BCTMP mills using traditional evaporation technology are already in operation in various parts of the world with increased load to evaporator. Paper industry initialized application of freeze concentration by using ice as a separating agent in the Louisiana-Pacific mill. Several drawbacks were discovered during their commercialization, including washing water freezing at 0°C, ice formation and plugging in the transportation pipe, difficulties with crystal size control, and high concentration of fiber fines. This process was proven to be successful in the lab and pilot scale, however, it has difficulties in the actual mill application. This work studied the possibility of concentration of pulp mill effluent through gas hydrates formation. Gas hydrates are solid solutions which gas/gases molecules are resided inside the crystal structure formed by water molecules. This process was designed to specifically address these problems associated with previous practice. A continuous gas hydrates formation unit that can perform crystallization, washing and separation functions is built. However, a batch reactor operated at constant volume and temperature were used extensively in this research. Co2 and i-C4H10 are selected to form gas hydrates. Specific problem such as possibility of formation, effectiveness of washing and final water purity were investigated. All of these data and experience can be very useful in the design of commercial unit. The reduction of effluent TSS and TDS via gas hydrate freezing are very effective to reach a level more than 99% removal. However, the reduction of COD removal is only about 60%. Through recrystallization gas hydrate experiments, the efficiency of COD removal can be improved to 80%. Therefore a gas hydrate modeling is developed to simulate multiple recrystallizsyion for predicting improved effluent COD reduction further.

Natural leathers from natural materials: progressing toward a new arena in leather processing.

Globally, the leather industry is currently undergoing radical transformation due to pollution and discharge legislations. Thus, the leather industry is pressurized to look for cleaner options for processing the raw hides and skins. Conventional methods of pre-tanning, tanning and post-tanning processes are known to contribute more than 98% of the total pollution load from the leather processing. The conventional method of the tanning process involves the "do-undo" principle. Furthermore, the conventional methods employed in leather processing subject the skin/ hide to a wide variation in pH (2.8-13.0). This results in the emission of huge amounts of pollution loads such as BOD, COD, TDS, TS, sulfates, chlorides and chromium. In the approach illustrated here, the hair and flesh removal as well as fiber opening have been achieved using biocatalysts at pH 8.0, pickle-free natural tanning employing vegetable tannins, and post-tanning using environmentally friendly chemicals. Hence, this process involves dehairing, fiber opening, and pickle-free natural tanning followed by ecofriendly post-tanning. It has been found that the extent of hair removal and opening up of fiber bundles is comparable to that of conventionally processed leathers. This has been substantiated through scanning electron microscopic analysis and softness measurements. Performance of the leathers is shown to be on par with conventionally chrome-tanned leathers through physical and hand evaluation. The process also exhibits zero metal (chromium) discharge and significant reduction in BOD, COD, TDS, and TS loads by 83, 69, 96, and 96%, respectively. Furthermore, the developed process seems to be economically viable.

Treatment of Textile Industry Waste Using Water Hyacinth

The efficiency of water hyacinth in the treatment of textile industry waste is reported in the present study. The effect of prior settling of the waste on the efficiency of the treatment was also studied. The hyacinth was grown in 100%, 50% and 25% concentrations of both original and settled wastewater for four days in laboratory tanks. The water hyacinth was found to be highly capable of removing pollutants from the original waste as compared to the settled waste, though the treatment was adequate even with the settled waste. The best treatment was obtained with 100% waste. There was 65.31% reduction in the conductivity in 100% settled waste and 53.86% reduction in 100% original waste. COD reduction in original waste was maximum with 25% concentration (97.35%) on the third day. With settled waste there was 92.97% reduction in COD on the third day. With settled waste the period of 4 days was needed to get a maximum reduction in conductivity, BOD, TS, TDS and TSS. For original waste, maximum reduction in conductivity, COD, BOD and TSS was noted on the third day. Total solids were reducedby 62.42% in 100% waste on the third day. 50% and 25% concentrations showed 41.35% and 47.21% reduction on the fourth day. Suspended solids were left in traces in 50% and 25% concentration on the fourth day. Among nutrients analysed on the fourth day, the overall reduction in potassium was maximum, i.e. 90.45% to 99.39%. Nitrogen, sodium and phosphorus were also reduced to a good extent. The initial and final harvested plant material was analyzed for various nutrients like Ca, Mg, Na, K, N & P. There was accumulation of sodium, potassium and nitrogen in the shoot from both original and settled waste; while the reduction in magnesium and nitrogen content was noted in the roots.

Chemical treatment for reuse of waste water effluents in saudi arabia

Reclamation of municipal wastewater is receiving increasing attention in Saudi Arabia. In the reclamation process desalination of wastewater becomes necessary when total dissolved solids (TSS) concentration is high. At most locations in Saudi Arabia the TDS of wastewaters ranges between 2000 and 4000 mg/l. A considerable fraction of the dissolved solids is due to salts of divalent cations, magnesium and calcium. Chemical precipitation of these salts would therefore be required as either a single step treatment in the reclamation process or as a preparatory treatment in conjunction with reverse osmosis or electrodialysis. The present study was conducted to investigate the chemical treatment of raw and biologically treated wastewater at Dhahran. Two chemicals lime and sodium hydroxide were used. Both were effective in reduction of TDS and hardness. Some typical preliminary results of treatment of secondary effluent are given in the following table. t001 Chemical Treatment of Secondary Effluent, Dhahran Treatment Total Hardness, mg/l as CaCo 3 Calcium Hardness mg/l asCaCo 3 Alkalinity, mg/l as CaCo 3 TDS,mg/l No treatment 1038 631 165 3875 CaO,500 mg/l 1018 978 172 3356 NaOH,500 mg/l 399 359 154 3095 CaO,500 mg +Na 2Co 3,600 mg/l 378 367 154 2168 NaOH, 500 mg/l+ Na 2CO 3 400 mg/l 107 87 266 2342 The low reduction of TDS and hardness when excess lime was used is due to the fact that recarbonation was not carried out. The phosphorus concentration was reduced from 4mg/l to less than 0.01 mg/l at 100 mg/l dose of either chemicals. The secondary effluent before and after treatment contained less than 0.01 mg/l of Cr and Cu and 0.5 mg/l Pb. Zinc Which was present in a concentration of 0.1 mg/l in the secondary effluent Was reduced <0.1 mg/l after chemical treatment. Similar results for inorganic constituents were obtained fro raw wasteWater. The total organic carbon was reduced from 91 mg/l to 38 mg/l and 20 mg/l respectively when CaO and NaOH were used. It is planned to study the effect of various chemical doses in further detail and also include other pollution parameters such as fecal coliforms, total count of bacteria, nitrogen, etc. in future studies.