Latex Wastewater Research Articles

Removal of H 2S in down-flow GAC biofiltration using sulfide oxidizing bacteria from concentrated latex wastewater

A biofiltration system with sulfur oxidizing bacteria immobilized on granular activated carbon (GAC) as packing materials had a good potential when used to eliminate H 2S. The sulfur oxidizing bacteria were stimulated from concentrated latex wastewater with sulfur supplement under aerobic condition. Afterward, it was immobilized on GAC to test the performance of cell-immobilized GAC biofilter. In this study, the effect of inlet H 2S concentration, H 2S gas flow rate, air gas flow rate and long-term operation on the H 2S removal efficiency was investigated. In addition, the comparative performance of sulfide oxidizing bacterium immobilized on GAC (biofilter A) and GAC without cell immobilization (biofilter B) systems was studied. It was found that the efficiency of the H 2S removal was more than 98% even at high concentrations (200–4000 ppm) and the maximum elimination capacity was about 125 g H 2S/m 3of GAC/h in the biofilter A. However, the H 2S flow rate of 15–35 l/h into both biofilters had little influence on the efficiency of H 2S removal. Moreover, an air flow rate of 5.86 l/h gave complete removal of H 2S (100%) in biofilter A. During the long-term operation, the complete H 2S removal was achieved after 3-days operation in biofilter A and remained stable up to 60-days.

Effects of pH adjustment by parawood ash and effluent recycle ratio on the performance of anaerobic baffled reactors treating high sulfate wastewater

The objective of this study was to compare the performance of anaerobic baffled reactor (ABR) treating concentrated rubber latex wastewater under different pH adjustment substances and recycling ratios ( R). Two ABRs, one received wastewater pretreated with NaOH and the other with ash, were operated at 35 °C under identical HRTs from 10 to 1.25 d. Results show that both ABRs had highest COD and sulfate removal efficiencies at HRT 10 d (averaged 82.71% and 96.16% of ABR-NaOH, and 80.77% and 96.60% of ABR-Ash, respectively), where majority of the influent COD and sulfate were removed by the first compartment of the ABR at all conditions tested. Increasing R (0, 0.3 and 0.5) raised the hydraulic loading on the system and resulted in a drop of organic removal efficiency and methane yield. Translocation of sulfate reducing bacteria and methanogens in the ABRs caused by increased organic loading and effluent recycle is discussed. The results show great potential of parawood ash as a pH adjustment substance for acidic wastewaters.

Electrolytic treatment of latex wastewater

A novel method of latex wastewater treatment was developed based on in-situ hypochlorous acid generation. The hypochlorous acid was generated in an undivided electrolytic cell consisting of two sets of graphite as anode and stainless sheets as cathode. The generated hypochlorous acid served as an oxidizing agent to destroy the organic present in the latex wastewater. For an influent COD concentration of 3,820 mg/L at an initial pH 4.5; current density of 74.5 mA/cm 2; sodium chloride content 3% and electrolysis period of 90 min, resulted in the following residual concentration pH 7.3; COD 78 mg/L; BOD 5 55 mg/L; TOC 45 mg/L; residual total chlorine 136 mg/L; turbidity 17 NTU and temperature 54°C, respectively. In the case of 2% sodium chloride content for the above, said operating condition resulted in a residual concentration of pH 7; COD 162 mg/L; BOD 5 105 mg/L; TOC 90 mg/L; residual total chlorine 122 mg/L; turbidity 26 NTU and temperature 60°C respectively. The energy requirements were found to be 35 and 50 Wh/L while treating 24 L of latex wastewater at 3 and 2% sodium chloride concentration at a current density 74.5 mA/cm 2. The observed energy difference was due to the improved conductivity at high sodium chloride content.

Ultrafiltration of ink and latex wastewaters using cellulose membranes

Ultrafiltration (UF) studies were conducted on latex and ink rinse wastewaters to assess the potential of concentrating the wastewater and recovering the permeate for reuse and recycling purposes. The physicochemical characteristics of the ink and latex wastewater suggested that the quality of both wastewaters was strongly dependent on the rinse process. A 4-fold and 7-fold concentration of ink and latex wastewater, respectively, may be achieved depending on the initial physicochemical characteristics of the wastewater. The UF system concentrated the latex wastewater to a total solids (TS) concentration of 275 g/L (approx. 28%) and to 99 g/L (approx. 10%) for ink wastewater. The permeates had turbidities ranging from 0.13 to 0.4 NTU. However, a significant percentage of the TS remained in the permeate of the ink wastewater which may require further treatment before it can be reused. For latex wastewater, it is likely that the retentate can be reused along with the permeate for rinsing purposes. For the ink wastewater, both pore blocking and cake resistance models were able to describe the change in flux with time. However, for the latex wastewater, pore blocking seemed to describe the flux with time data better than the cake resistance models. The fouling coefficient, K, for the pore blocking model was found to be a function of the TS present in the latex wastewater.

Recycling of latex wastewater by chemical treatment

Glove factories, wastewater contains a large amount of latex which is not biodegradable. Latex wastewater can be treated through: aeration, chlorination, sulfonation, biological treatment, filtration, coagulation, ozon oxidation and using activated carbon. In this paper a new method for treating latex wastewater has been reported. Sulfuric acid has been used for separation of latex from wastewater. This method is compared with limits. The other advantages of this method are recovery of latex for other uses, decreasing coagulation and biological method. BOD and COD of the effluent are lower than DOE limits. The other more advantages of this method are recovery of latex for other uses, decreasing energy consumption and recovery of water. Keywords: Latex, wastewater, Recovery, Chemical treatment REFERENCES Aodian, G. (1970). Principles of Polymerization. Mc Graw-Hill Book Company. Bloomfield, G.F. (1961). The Applied Science of Rubber. Edward Arnold Ltd.,London. Schatze. T.C. (1945). Effect of Rubber Wastes on Sewage Treatment Process. Sewage Works J. 17, 497. Black. O.R. (1946). Study of Wastes from Rubber Industry. Sewage Works J.18, 1169. Sechrist, W.D. and Chamberlian, N.S. (1951). Chlorination of Phenol-bearing Rubber Wastes. In Proceedings of 6th Industrial Waste Conference, Purdue University. p. 396. Mills, R.E. (1957). Progress Report on the Bio-oxidation of phenolic and 24-wastewater. In Proceeding of 4th Ontario Industrial Waste Conference, p. 30. Rostenbach. R.E. (1952). Status Report on Synthetic Rubber Wastes. Sewage Ind. Wastes 24, 1138. Morzycki, J. et al. (1966). Effluents from Sewage Contaminated with Latex.Chem. Abstracts 64, 3192. Ruchhoft, C.C. et ai. (1948). Synthetic Rubber Waste Disposal. Sewage Ind. Wastes 20,180.