Rinsing Water Research Articles

Treatment and Desalination of Wastewater Generated After Steel Degreasing and Pickling in the Tunisian Galvanization Industry

A case study of galvanization wastewater treatment was carried out to preserve the environment and to suggest a solution to the Metal Galvanization of Poulina Group Holding MBG-Galva industry located in Tunisia for reducing effluent organic matter, heavy metals, and salt contents. The current industry had two baths of rinsing water after steel degreasing and pickling steps. The chemical oxygen demand (COD) and pH of the first bath were very high compared to the second bath, which exhibits a low pH with high salinity and high heavy metals contents. Coagulation-flocculation and electrodialysis were examined as treatment processes for rinse water obtained after steel degreasing, while precipitation-oxidation and membrane distillation were combined for pickling rinse water treatment. Aluminum sulfate and sodium alginate were used, respectively, as coagulants and flocculents under optimal conditions determined through the Jar test. After the electrodialysis step, the removal rates were found to be 89.6% for conductivity, 93% for COD, 90 to 96% for salt content, and 82% to 99.5% for heavy metals. For the second effluent, the conductivity of wastewater was reduced by 97%, and heavy metals and COD were removed. The lab-scale experiment implementation proved that using the current process has a high impact on obtaining zero liquid reject in the manufactory, and reusing it in the same bath is an opportunity for water preservation. Solid waste characterized by X-rays showed that lead oxide and iron can be recovered from galvanization industry wastewater. Scaling the combined pretreatment and desalination system in a demonstration unit helps the galvanization industry reuse the water in the same industry and prevent environmental pollution.

The potential of swimming pool rinsing water for irrigation of green areas: a case study

The aim of the research was to check the possibility of using the rinsing water after rinsing the recreational pool filters, cleaned with the rinse water recovery system, for irrigation of green areas. The system consists of the following stages: flocculation, pre-filtration, and ultrafiltration based on filter tubes. The degree of contamination of the rinse waters before and after the treatment process was assessed by means of physicochemical and microbiological tests, and then compared with the permissible parameter values for wastewater discharged into the ground or water. Thanks to the use of flocculation and appropriate ultrafiltration, the high level of total suspended solids and total organic carbon was reduced, which allows for safe discharge of purified water into the environment.Graphical Circular economy, wash water, zero waste technologies, water footprint, water recycling

A Reverse Osmosis Process to Recover and Recycle Trivalent Chromium from Electroplating Wastewater.

Electroplating generates high volumes of rinse water that is contaminated with heavy metals. This study presents an approach for direct metal recovery and recycling from simulated rinse water, made up of an electroplating electrolyte used in industry, using reverse osmosis (RO). To simulate the real industrial application, the process was examined at various permeate fluxes, ranging from 3.75 to 30 L·m−2·h−1 and hydraulic pressures up to 80 bar. Although permeance decreased significantly with increasing water recovery, rejections of up to 93.8% for boric acid, >99.9% for chromium and 99.6% for sulfate were observed. The final RO retentate contained 8.40 g/L chromium and was directly used in Hull cell electroplating tests. It was possible to deposit cold-hued chromium layers under a wide range of relevant current densities, demonstrating the reusability of the concentrate of the rinsing water obtained by RO.

Effects of Rinsing Water Temperature and Preheated Composites on Microleakage of Composite Restorations with Two Bonding Agents.

Objectives: The aim of this study was to evaluate the effects of rinsing water temperature and preheated composites on microleakage of class V restorations with two different bonding agents. Materials and Methods: Eighty class V cavities were prepared in the buccal and lingual surfaces of 40 molars. Single Bond and Prime and Bond NT bonding agents were used. The teeth were divided into four groups of 10. G1: After acid etching, cavities were rinsed with 23˚C water and filled with 23˚C composite resin. G2: Rinsing water and composite resin had 55˚C temperature. G3: Rinsing water had 55˚C and composite resin had 23˚C temperature. G4: Rinsing water had 23˚C and composite resin had 55˚C temperature. The specimens were immersed in 0.5% basic fuchsine dye. Microleakage scores were analysed with the Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests. Results: There were significant differences in microleakage of specimens prepared with Single Bond and Prime and Bond NT only in group 1 (P<0.05). There were no significant differences between the microleakage of groups rinsed with different water temperatures (P>0.05). There were significant differences between the unheated and preheated composite groups (P<0.05). Conclusion: Preheating of composite is a valuable method to increase its adaptability and decrease microleakage of composite restorations.

Study on Protein Recovery Process of Silver Carp Surimi Rinsing Water

Rinsing water from the production of sliver carp surimi was applied as the research object. The effect of different settling time, temperature, acid species, pH, flocculant species and their addition on the supernatant permeability, protein recovery yield and protein polyacrylamide gel electrophoresis (SDS-PAGE) of recovered proteins from surimi rinsing water were investigated. The results showed that, when adjusted the pH to 5.5 with hydrochloric acid prior to settlement, settlement at 4℃ for 60 min was benefit for protein recovery from rinsing water. The protein recovery yield and light transmittance of the supernatant of rinsing water were increased to by 65.8% and 50.1%, respectively, when adjusted the pH to 5.5 with hydrochloric acid prior to settlement, and the values were higher than those of acetic acid and citric acid. Furthermore, protein recovery yield and light transmittance of the supernatant of rinsing water were increased to 85.8% and 87.8%, respectively, with the presence of 0.6 mg/mL chitosan. The SDS-PAGE results showed that the molecular weight of the recovered protein from surimi rinsing water was mainly distributed at 35, 42, 48, 63, 100, and 190 kDa. After a series of treatments, the protein content gradually increased (except for the band at 190 kDa), and multiple new protein bands were generated around 25.0~28.0 kDa. Accordingly, the appropriate conditions for protein recovery from the surimi rinse water were that the pH was adjusted to 5.5 with hydrochloric acid, 0.6 mg/mL chitosan was added, following by settlement at 4℃ for 60 min. This research could provide theoretical basis and practical guidance for protein recovery and waste water purification from surimi rinsing water industrially.

Efficient Waste Water Treatment Improves Rinsing Water Quality

Efficient Waste Water Treatment Improves Rinsing Water Quality

Bronchoscope-related Pseudomonas aeruginosa pseudo-outbreak attributed to contaminated rinse water

Increased percentage of Pseudomonas aeruginosa from bronchoalveolar lavage fluid of patients in June 2016 was observed. P aeruginosa were also obtained from flexible bronchoscope and rinse water in the microbiological surveillance in June 2016. Reprocessing procedure of bronchoscope was assessed, and environmental samples were collected. P aeruginosa isolates recovered from bronchoalveolar lavage fluid of patients between May and September 2016 and environment were characterized using multilocus sequence typing and pulsed-field gel electrophoresis. A novel multilocus sequence type (ST) of P aeruginosa was defined as ST 2387. ST671 and ST 2387 were both cultured from bronchoscopes and connecting tube in manual reprocessing cleaning equipment. One strain from a patient was indistinguishable from the clones obtained from the bronchoscope and connecting tube revealed by pulsed-field gel electrophoresis. Two strains from 2 patients from the burn intensive care unit were identical, and highly related to 2 other strains from the burn intensive care unit. The persistence of P aeruginosa in bronchoscopes, connecting tubes, and final rinse water was terminated by replacement of the connecting tube. We report a pseudo-outbreak of P aeruginosa associated with bronchoscope, for which connecting tube was the hidden reservoir for contaminating bronchoscopes. This highlights that effective measures are needed to control the bacterial load in final rinsing water to protect reusable equipment from contamination in reprocessing and cleaning.

7-2-1 湿式BDF製造機から発生する洗浄廃水のコペルニクス的処理法(7-2 環境対策1,Session 7 環境対策・リサイクル)

7-2-1 湿式BDF製造機から発生する洗浄廃水のコペルニクス的処理法(7-2 環境対策1,Session 7 環境対策・リサイクル)

Application of electrodialysis technique to recover contaminated rinsing water from gold electroplating processes

The aim of the present work was to evaluate the possibility of using an electrodialysis technique to recover rinsing water contaminated with the electrolyte during the process of gold electrodeposition. During the rinsing process the electrolyte, containing gold, silver, cyanide and contaminants, is dragged from the bath with the plated components. The more the rinsing water is used the more it becomes concentrated and therefore water replacement is necessary. In these studies three different types of electrodialysis cell containing two, three and five separate compartments were used. Two kinds of ion selective membranes, a cationic Nafion 450 and an anionic Selemion AMV, were used in the construction of the cells. The total cell potential, membrane potential and polarisation potential as a function of applied current were evaluated. The results show that it is possible to extract an average of 56% of all metal and cyanide from the rinse water working at 30 mA cm−2 for 190 h. However, a more efficient extraction of 75% of all the metals and cyanide was obtained within 270 min of electrodialysis at a current density of 20 mA cm−2. The results of this study showed that electrodialysis is suitable for removing contaminants from rinsing water to be returned to the process.

Influence of permeation on air/water cleaning of spiral wound membrane NF/RO elements

To improve hydraulic conditions, periodic air/water cleaning (AWC) is applied to a nanofiltration (NF) spiral wound membrane (SWM) element under permeation conditions to control biofouling and particulate fouling. A pilot study was carried out for 212 days with a vertically positioned SWM element fed by tap water enriched with a biodegradable compound (60 mu g acetate-C l(-1)). Operational parameters were daily recorded, rinse water was collected and analysed and a membrane autopsy was performed at the end of the experimental run. Normalized pressure drop (NPD) increased as a result of biofouling and particulate fouling, and could be controlled by periodic AWC, while the membrane transport coefficient (MTC) and retention based on the conductivity remained constant. Rinsing water from AWC contained biomass and particulate matter (iron), predominantly during the first few minutes of AWC. Membrane autopsy revealed active biomass and inorganic deposits (mainly iron and copper) at the inlet and outlet of the membrane element. The use of AWC in (vertically positioned) NF/RO SWM elements under permeation conditions improved the control of membrane fouling (especially biofouling and particulate fouling) and did not compromise the integrity of the membrane element (until day 60).

Heavy metal removal and cyanide destruction in the metal plating industry: an integrated approach from egypt

Wastewater produced from a metal plating is a major environmental problem. Industrial auditing revealed that the main source of pollution mainly originated from rinsing water. The characterization of final effluent showed that it is highly contaminated with hazardous heavy metals and cyanide. The concentration of copper, hexavalent chromium, nickel, and cyanide in the rinsing water of metal plating department was 14.8, 40.9, 13.3, and 19 mg/l, respectively. The concentration of cyanide and zinc from the galvanizing department reached 60 and 80 mg/l. The remediation scheme included the application of in-plant control measures via changing the rinsing process followed by the destruction of cyanide and reduction of hexavalent chromium bearing wastes. The pretreated wastes were then mixed with other industrial wastes prior to a combined chemical coagulation-sedimentation using lime and/or lime in combination with ferric chloride. The results indicated that, after applying the waste minimization measures alone at the source, prior to final treatment of industrial waste, removal rates of cyanide, copper, nickel, and chromium concentrations were 23.2%, 14.9%, 32.3%, and 55.3%, respectively in the rinse water from metal plating department. Furthermore, the removal rates of cyanide and zinc in the galvanizing department reached 59.7% and 24.3. The integrated control measures and treatment scheme led to more than 99% removal of copper, nickel, chromium, and zinc, while the complete removal of cyanide was achieved in the final effluent.

Rinse water regeneration in stainless steel pickling

Since stainless steel must be rinsed with water after pickling operation with mixtures of nitric and hydrofluoric acids, the present investigation was undertaken to define a major step towards the close loop circulation of water in steel plant. This can be done by a new procedure for removing also nitrates from rinse water in such a way that clean water can be recycled back to rinsing use. The concentrated part of used rinse water will be fed to pickling acid regeneration plant, where nitric and hydrofluoric acids can be separate and recycled back to the pickling use. The tests were carried out mainly in one of Outokumpu’s production plants in Sweden. Membrane technique was used for rinse water treatment. A filtering system based on reverse osmosis was developed to separate the acids and metals from the rinsing water. A pre-filtering method necessary for reverse osmosis was tested. Since the composition of permeate is not applicable for direct reusage in the rinsing zone, post-treatment methods were examined. Amberlite IRA67 ion exchange resin was tested for treatment of reverse osmosis filtrate (pH adjustment). For the recovery of the mixed acids, the concentrate of reverse osmosis was further treated with electrodialysis. On the basis of these results, a regeneration concept was developed, in order to close the rinse water loop. The proposed rinse water recycling concept reduces the overall usage of water.

Dynamic simulation of rinsing and regeneration networks based on high pressure RO

The dynamic behavior of rinsing and regeneration networks (RRNs) has been investigated with emphasis on product quality assurance. RRNs allow recycling of discharged process bath liquor as well as a re-use of the purified rinsing water even at zero-water emission levels. However, during RRN start-up, inherent instabilities in the network might jeopardize the workpiece surface finish due to inconstant process bath composition, which is determined by the recycled concentrate, and insufficient final surface cleanliness. The objective of the present paper is to simulate start-up conditions and to analyse their effects on process stability. To implement these goals, a general dynamic model was developed on the basis of differential mass and material balances in combination with a constant-ratiomodel for high pressure reverse osmosis (RO). Additionally, a film theory expression was included into the latterto take into account the negative effect of concentration polarization near the membrane wall. In a case study, composed of an electroplating process comprising seven rinsing baths, an ion exchanger and a disc-tube RO module, it was shown that the final product quality is strongly influenced by start-up conditions. For the considered case, the quality prerequisites were achieved through starting up the regeneration units and the freshwater supply with anoptimal time delay of 8 % of the overall rinse water retention time.

Treatment of Rinsing Water from Bottle Washing Machines by Membrane Filtration with the Objective of Reuse

This paper presents the processes tested for the pretreatment of rinsing water from bottle washing machines, the objective of which is to retain suspended and colloidal organic and inorganic matter in order to prevent membrane scaling and fouling in the downstream reverse osmosis stage. Microfiltration and ultrafiltration as well as two‐layer anthracite/sand filtration proved to be suitable pretreatment processes. The selection of membranes suitable for producing drinking water from rinsing water and the results from the operation of a demonstration plant in a brewery are also dealt with.

Profitability of in-plant modifications in pollution control

Abstract This case study was developed in view of setting up a demonstration project on “revealing the profitability of clean technology in small-scale electroplating unit”. The research was conducted in a small-scale electroplating shop located in Bangkok. A set of simple in-plant control measures such as dragout recovery, spray rinsing technique and rinse water agitation were implemented. Quantitative data, obtained from the monitoring of wastewater before and after process modifications, have indicated a substantial reduction both in quantity and strength of wastewater generated. Water consumption was reduced by approx. 35% of total rinsing water, which is 19% of total process water consumption. Average metal concentrations in wastewater was reduced 73% for Cr-, 71% for Ni- and 54% for Cu-plating rinse water.

Environmentally friendly method in reactive dyeing of cotton

The recipe for reactive dyeing of cotton can be divided into three steps: the pretreatment, the dyebath and the final rinse. The consumption of chemicals and water in the rinse has been found to be considerable: three quarters of the total COD discharge of the recipe have relations to auxiliary chemicals used and three quarters of the total water consumption have relation to the rinse. The improvement potential in the rinsing procedure were found to be considerable, and the newly developed recipe focuses on improvements in the rinse. Tests with the new recipe have documented that neutralization, detergents and complexing agents can be left out completely with no adverse effect on product quality. All recognized tests of fastness and shade have been performed and evaluated in cooperation with the dyehouses. More than 50 full-scale dyeing experiments have been carried out in jets, overflow and drum batch machines. The experiments include 25 different reactive dyestuffs, among these azo, anthrachinon, phtalocyanin and formazan dyestuffs, including both monoreactive and bireactive dyestuffs of which 15 had the vinyl sulfone as reactive group. The dyestuffs have been combined in 20 different recipes covering very light to very dark shades. Hot membrane filtration of the hot rinsing water has been investigated in parallel projects and it is documented that membrane filtration saves chemicals, water and production time, and also gives large energy savings in one new recipe.

Environmentally friendly method in reactive dyeing of cotton

The recipe for reactive dyeing of cotton can be divided into three steps: the pretreatment, the dyebath and the final rinse. The consumption of chemicals and water in the rinse has been found to be considerable: three quarters of the total COD discharge of the recipe have relations to auxiliary chemicals used and three quarters of the total water consumption have relation to the rinse. The improvement potential in the rinsing procedure were found to be considerable, and the newly developed recipe focuses on improvements in the rinse. Tests with the new recipe have documented that neutralization, detergents and complexing agents can be left out completely with no adverse effect on product quality. All recognized tests of fastness and shade have been performed and evaluated in cooperation with the dyehouses. More than 50 full-scale dyeing experiments have been carried out in jets, overflow and drum batch machines. The experiments include 25 different reactive dyestuffs, among these azo, anthrachinon, phtalocyanin and formazan dycstuffs, including both monoreactive and bireactive dyestuffs of which IS had the vinyl sulfone as reactive group. The dyestuffs have been combined in 20 different recipes covering very light to very dark shades. Hot membrane filtration of the hot rinsing water has been investigated in parallel projects and it is documented that membrane filtration saves chemicals, water and production time, and also gives large energy savings in one new recipe.