INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 4, No 5, Copyright by the authors - Licensee IPA- Under Creative Commons license 3.

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1 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 4, No 5, 2014 Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0 Research article ISSN ABSTRACT Pumice filtration of flocculated pond 1 effluent Dentistry College, Wasit University, Wasit, Kut, Iraq saka1_nz@yahoo.com.au doi: /ijes The use ofpolyferricsulfate(pfs) flocculation, followed by pumice filtration, reduced the levels of resin acids, colour and 5 Day biochemical oxygen demand(bod5)in pond 1 water by more than 90% and appears to at least as effective as the existing secondary treatment system. This Observation indicate that primary flocculation/filtration technology could be as least as efficient as the existing secondary system process for resin acid, 5 Day biochemical oxygen demand(bod5)and turbidity removal and more effective for colour removal. Preliminary cost estimates also indicate its probable cost effectiveness; this could be improved by the possibility of recovery or partial recovery and reuse of the flocculating agent. Keywords : biological treatment system, flocculating agent, 5 Day biochemical oxygen demand (BOD5),pumice filtration, colour and resin acids. 1. Introduction In previous investigations more than 90% of the resin acid content of primary effluent water generated by pulp and paper mill processing operations are not associated with particles (1). On the other hand we have previously reported that > 70% of the extractable resin acids discharged from Tasman's biological treatment system, to the Tarawera River, were bound to micron particles (2, 3). It was therefore of interest to determine if the amount of particle associated resin acids, 5 Day biochemical oxygen demand(bod5)and chromophoric species present in primary effluent water could be increased by treatment with flocculants. A combination of sedimentation and/or low cost filtration might then be used as a primary treatment, to replace or supplement biological treatment. As effluent standards from pulp and paper mill wastewater treatment plants have becomemore stringent, the use of coagulants and/or flocculants as a tertiary treatment for bleachedkraft effluents has already been trailed. Hodgson et al (5,4) have reported that polyacrylamide treatment of a bleached kraft effluent reduced the colour, chemical oxygen demand (COD), adsorbed organic halide (AOX), and 2,3,7,8-tetrachlorodibenzofuran and mixed-function oxygenase induction by 61%, 24%, 23%, 80% and 18% respectively. The principle objective of the work reported in this paper was evaluation of the extent to which flocculating agents can remove resin acids, colour, 5 Day biochemical oxygen demand (BOD5)and turbidity from mill effluent prior to biological treatment. Received on February 2014 Published on April

2 2. Methods and materials The protocol used in filtration experiments was granular filtration studies were performed using the apparatus shown in Figure 1. It consisted of a 425 x 44 mm glass column, fitted with a No. 1 glass sinter at the base of the column to support the media and a 370 mm collection tube (side arm). Care was taken to ensure the collection tube (side arm) was maintained in saturated state to avoid the possibility of channeling due to air penetration. Figure 1: Illustration of the glass column design. Filtration experiments were performed using a known weight of granular material, sufficient to give a 310 mm bed. The void volume of the media was determined in a separate experiment by measuring the amount of water required to fill the void-volumes.before use, the medium bed was back washed and flushed with between 10 and 15 bed void-volumes of tap water until the turbidity and absorbances at 270, 340 and 440 nm were less than 0.25 NTU and respectively. Samples to be filtered were applied to the column and tap water was added as the experiment proceeded to maintain constant head pressure. Typically, the first three bed void-volumes from the column were discarded. Filtration trials were continued until 3 L of untreated effluent, or 1 L of flocculated effluent, had been collected. Absorbance and turbidity measurements were made of each successive 100 ml of column eluent. Results are expressed as the mean for the experiment. In general variation in data after the initial flushing of system was within the range 7-10%.Water samples in screw capped 2.5 L glass winchesters were collected from the outflow ofthe treatment pond 1 for two pulp mills located on the banks of the Tarawera River, North Island, New Zealand (1, 2). Water samples were stabilized at the time of collection by the addition 0.1% of sodium azide (3, 4) and stored at 4-8 C until required for analysis.pond 1 water samples (1 L) were flocculated using Polyferricsulfate(PFS) (10-60 mg/l), orpolyaluminum chloride PAC (10, 36 or 100 mg/l) at ph (PAC), or (PFS)(4). These phs are similar to those found by several other authors (Beulker and Jakel) (6); Edzwald(7). The flocculation process was monitored by particle size analysis. A portion of each of the thoroughly mixed flocculant solutions (1L) was filtered through 0.85mm (190 g), 1.6 mm ((143 g),2.4 mm (120 g) and 3.1 mm (93 g) pumice. The ph of first portion (80 ml) portion of the filtrates was adjusted to 7, prior to resin acid, colour, turbidity analysis, which were performed (1, 8). The other portion 1047

3 was used for 5 Day biochemical oxygen demand (BOD5)measurement (9).After removal of the 1L sample for pumice filtration, flocculated material was allowed to settle for 2-3 h. Precipitated material, recovered by sequential filtration, was transferred using a spatula to a 200 ml beaker and resolublised.100 ml of distilled water by stirring at ph 10 and liquid/liquid extracted at ph 10 as reported previously (3). 3. Result and Discussion Results determined for a series of experiments in which PFS treatment (0-40 mg/l) was followed by filtration through a column packed with pumice (0.85 mm diameter) are presented in Table 1Flocculation using mg/l PFS followed by filtration removed 89-97% of resin acids. The significance of pumice material size was assessed in experiments in which a fixed dose of PFS (20 mg/l) was utilised, and variable sizes of sieved pumice material were used. The greatest removal of flocculated resin acid material was achieved using 0.85 mm pumice (Table 2). Flocculation using 20 mg/l PFS followed by variable sizes of sieved pumice, 0.85 mm pumice removed 91% of resin acids. 3.1 PFS flocculation and pumice filtration of BOD5 and colour The extent to which PFS flocculation, in combination with 0.85 mm pumice filtration.reduced BOD5 and turbidity was determined. Results are presented in Table 3. A 20 mg/l dose of PFS, followed by 0.85 mm pumice filtration, reduced colour at 440 nm and turbidity by 89% and BOD5 by 75%(Table 3). The data presented represented in Table 3 can be compared with resin acid data presented in Table 3. It is clear that the decline in BOD5 with increasing PFS dose (5), corresponds closely to that determined for resin acids (Figure 2). The results presented in Tables 1 and 2 show that the total resin acids, BOD5 (Figure 2), absorbance at 440 nm (Figure 3) and turbidity (Figure 4) of pulp and paper primary effluent can be reduced by greater than 90% by PFS flocculation followed by pumice filtration. 3.2 Cost calculations Using the data obtained from the flocculation/filtration studies reported above it is possible to estimate the cost of PFS required to treat Tasman's primary effluent. Assuming a daily discharge of 160 ML/day, a PFS requirement of 20 mg/l comes to 3.2 tonne/day. At the bulk cost of PFS (10) the chemical cost would be of the order of $1.5 M/year. Any recovery of flocculant would reduce this chemical consumable cost. Other operating costs that would have to be met include the cost of pumice mining, preparation, transportation and disposal. Depending on the flocculation and filtration technologies chosen, other operating costs would be incurred. However, flocculation/ filtration treatment of primary effluent appears as an attractive option that warrants further investigation. It offers the possibility of reduced total effluent treatment costs (if it can take the place of secondary treatment) and improved effluent quality, particularly in regard to colour reduction. Table 1: Resin acid levels ( g/l) identified in pond 1 water samples after flocculation with 0-40 mg/l polyferricsulfate and filtration through 0.85 mm pumice(95 g/l of water). Seco Pim 18-Ab DHAA 13-ene Abiet Cls total % pond 1 A

4 pond 1 B average a % PFS dose 0 mg/l % b 5 mg/l % 10 mg/l % 15 mg/l % 20 mg/l % 25 mg/l % 30 mg/l % 40 mg/l % a average of duplicate extraction of pond 1 water, collected 27/4/00, b recovery relative to unfiltered waterabbreviations: Seco = secodehydroabietic acids 1 and 2, Pim = pimaric acid, 18-Ab = abietan-18-oic acid, DHAA = dehydroabietic acid, 13-ene = abiet-13-enoic acid, Abiet = abietic acid, Cls = 12-chloro, 14-chloro and 12,14 dichlorodehydroabietic acids, total = total resin acids, % = recovery relative to unfiltered water. Table 2: Resin acid levels ( g/l) identified in pond 1 water after flocculation with 20 mg/l PFS and filtration through a column containing mm pumice material. Seco Pim 18-Ab DHAA 13-ene Cls total % pond 1 water a,b (8121) % pond 1 + pumice 0.85 mm (190 g) c % c 1.6 mm (143 g) % 2.4 mm (120 g) % 3.1 mm (93 g) % a collected 27/7/09, b not filtered, c the weight of pumice, d recovery relative to unfiltered water.abbreviations: Sec = secodehydroabietic acids -1 and 2, Pim = pimaric acid, 18-Ab = abietan-18-oic acid, DHAA = dehydroabietic acid, 13-ene = abiet-13-enoic acid, Cls = 12- chloro, 14-chloro and 12,14-dichlorodehydroabietic acids, total = total resin acids, % = recovery relative to unfiltered water. Table 3: Absorbance at 270, 340 and 440 nm and turbidity (NTU) determined for pond 1 water samples after flocculation with 0-40 mg/l PFS and filtration through a 0.85 mm pumice column (95 g/l of water). Absorbance % remaining turbidity BOD5 270 nm 340 nm 440 nm 270 nm 340 nm 440 nm NTU pond % 100% 100% PFS dose 0 mg/l % 54% 32%

5 Percentage remaining Pumice filtration of flocculated pond 1 effluent 5 mg/l % 53% 24% mg/l % 49% 19% mg/l % 40% 13% mg/l % 23% 11% mg/l % 23% 11% mg/l % 18% 5% mg/l % 18% 5% Figure 2: BOD5 and resin acid levels determined for pond 1 water, collected 27/7/09, following treatment with various doses of PFS and filtration through 0.85 mm pumice. 80% nm remaining % 70% 60% nm remaining % 50% 40% nm remaining % 30% 20% 10% 0% Dose (mg/l) Figure 3: % Absorbances at , and 440 nm determined for pond 1 water, collected 27/7/09, following treatment with various doses of PFS and filtration through 0.85 mm pumice. 1050

6 Figure 4: % Turbidity remaining for pond 1water, collected 27/7/09, following treatment with various doses of PFS and filtration through 0.85 mm pumice. 4. References 1., Langdon G. Alan and Wilkins L. Alistair, (2006), Particle association of resin acids in the biological treatment of a New Zealand pulp and paper mill, Bulletin of environmental contamination and toxicology, 76 (3), pp , Wilkins L. Alistair and Langdon G. Alan, (2000), Speciation of pulp mill derived resin acids in the TaraweraRiver, New Zealand,Bulletin of environmental contamination and toxicology, 64(5), pp , Langdon G. Alan and Wilkins L. Alistair, (2005), Speciation and stability of particle-bound pulp and paper mill sourced resin acids in sodiumazide preserved recipient water. Bulletin of environmental contamination and toxicology, 75 (3), pp and Alnaqishbadi A. A.,(2013), Flocculation of effluent water samples. Tikrit journal of pure science 18(3), pp Hodgson, A. H., Hitzroth, A. J., Premdas, P. D., Hodson, P. H. and Duff, S. J., (1998), Effect of tertiary coagulation and flocculation treatment on effluent quality from a bleached kraft mill, Tappi journal, 81(2), pp Stephenson, R. J. and Duff S. J. B., (1996), Coagulation and precipitation of a mechanical pulping effluent 1. Removal of carbon and turbidity, Water research, 30(4), pp Edzwald, J. K, (1993), Coagulation in drinking water: particles, organic and coagulant, Water science andtechnology, 27(11), pp , Langdon G. Alan and Wilkins L. Alistair, (2008), Studies of transformation and particle-binding of resin acids during oxidative treatment of 1051

7 effluent from two New Zealand pulp mills, Bulletin of environmental contamination and toxicology, 80(2), pp Eugene W. Rice, Rodger B. Baird, Andrew D. Eaton and Lenore S. Clesceri (2012). Standard methods for the examination of water and wastewater, American Water Works Association, American Public Works Association, Water Environmental federation,22nd edition. 10. Orica Chemnet, Auckand,(2014). Personal Communication. 1052