Disposal Problem of Arsenic Sludge Generated During Arsenic Removal from Drinking Water

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ScienceDirect Procedia Environmental Sciences 35 (2016) 943 – 949

International Conference on Solid Waste Management, 5IconSWM 2015

Disposal Problem of Arsenic Sludge Generated During Arsenic Removal from Drinking Water Prasanta Mandal, S.R.Debbarma, Arup Saha, Biswajit Ruj* CSIR-Central Mechanical Engineering Research Institute (CMERI), M.G.Avenue, Durgapur, WB, India

Abstract Arsenic (As) causes acute and chronic toxicity, it harm the skin and associated with increase risk of cancer in the skin, bladder and kidney. It is very difficult to diagnose the early symptoms of arsenicosis so it depends largely on awareness with improving the quality of drinking water. There are several methods are available for removal of As from water. The most commonly used technologies are oxidation, co-precipitation, adsorption, absorption, coagulation, ion-exchange resin, lime treatment and membrane techniques. Now today the safe disposal of large quantity of As contaminated sludge generated from As removal water treatment plant which contain about 5-7 kg of arsenic per cubic meter due to risk of underground water contamination as arsenic has very high leaching potential. For safe disposal of solid hazardous waste of As requires treatment. A long term solution appears to solidification/stabilization (s/s) of As-sludge and using it for beneficial purposes like bricks and concretes etc. In the field of active research, this paper identifies the gap between the implementation of process as well as new technologies for safe disposal of arsenic sludge. © 2016 Published by Elsevier B.V.B.V. This is an open access article under the CC BY-NC-ND license 2016The TheAuthors. Authors. Published by Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility ofthe organizing committee of 5IconSWM 2015. Peer-review under responsibility of the organizing committee of 5IconSWM 2015 Keywords:Arsenic Sludge, Arsenic Removal, Drinking Water

Introduction Arsenic is a naturally occurring semi-metal element present in the environment in both inorganic and organic forms. Inorganic arsenic is considered to be the most toxic form of the element and is found in groundwater and surface water [1].Now elevated concentrations of arsenic 50-100 μg/l are found in groundwater in some areas of India, Bangladesh, Chile, China, Argentina, Mexico, Hungary, Taiwan, Vietnam, Japan, New Zealand, Germany

* Corresponding author. E-mail address:[email protected], [email protected]

1878-0296 © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of 5IconSWM 2015 doi:10.1016/j.proenv.2016.07.084

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and the United States due to naturally occurring arsenic in the aquifer sediment where as new guideline recommended by WHO is 10μg/l [2,3,4]. In humans, inorganic arsenic is readily absorbed from the gastrointestinal tract and is primarily transported in the blood bound to sulfhydryl groups in proteins and low-molecular-weight compounds, such as amino acids and peptides[5,6].A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning of drinking water[7]. Current Standards (MCL) for Arsenic in Drinking Water World Health Organization 10 ppb Environmental Protection Agency

10ppb

USA

10ppb

European Union

10 ppb

Australia

7 ppb

Bangladesh

50 ppb

India

50 ppb

New Jersey

5 ppb

Activated alumina as adsobent has been used in most of the arsenic removal plants for removal of arsenic. After long use, efficiency of those plants are decreased and needs regeneration of the activated alumina for its further use. For several numbers of arsenic removal plants there is a regenerating unit around this area. During regeneration, a large quantity of solid waste residue (SWR) As-sludge is produced which is highly rich in arsenic and dumped into a concrete chamber near the regenerating unit which contains about 5-7 kg of arsenic per cubic meter of sludge[8,9,31]. This sludge is hazardous as per the Resource Conservancy and Recovery Act (RCRA) of USEPA (1986) and is much above the permissible standard (0.2 g/m3) for its direct disposal into the inland water environment (CPCB-MEF, GOI 1995–1996)[10]. As environmental regulations become more stringent and volume of generated sludge continues to increase, traditional sludge (SWR) disposal methods are not suitable and require changes. So, disposal and solidification/stabilization (s/s) of arsenic contaminated sludge using practicable and economical methods is a great challenge for the engineers and researchers. Natural Source of Arsenic Contamination in Ground Water: Arsenic is a semimetal or metalloid a natural constituent of earth’s crust. Its present in several stable oxidation states –III, -I, 0, +III, +V but the +III and +V states are most common in natural system and also dominates in aqueous medium,specifically As (III) is 25–60 times more toxic than As (V) [11].Arsenic containing pyrites disperse and contaminate the ground water,arsenopyrite (FeAsS) is probably the most common mineral source of arsenic [12,13,14]. FeAsS+O2+H2Oĺ AsO43-+ Fe3+ + SO42-+ H+ Important factors controlling the dissolution of Arsenic are: x pH x Temperature x Moisture (hydrolysis) x Redox character of the species x Reactivity of the species towards CO2& H2O. x Solubility Indian Scenario: Investigations by Central Ground Water Board (CGWB) reveals that arsenic contamination (>0.05 mg/L) is affecting the states of West Bengal, Bihar, Uttar Pradesh, Assam, Chhattisgarh. The Bengal Delta Plain (BDP) covering Bangladesh and West Bengal in India is the most severe case of groundwater arsenic contamination [15].

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Global Scenario: Arsenic level beyond permissible limits in drinking water is the main cause of arsenic toxicity in the world. Taiwan, China, Chile, Argentina, Mexico, India, Hungary Bangladesh, USA and Thailand Reported such type of contamination [2].The summary of the current global scenario of arsenic contamination is shown in Figure.

Fig. 1.

Global scenario of arsenic contamination of ground water Health Effect: Arsenic is a substance that is carcinogenic – capable of causing cancer. Chronic arsenic toxicity (arsenicosis) due to drinking of arsenic contaminated ground water is a major environmental health hazard throughout the world including India. Long-term exposure to arsenic in drinking water can cause cancer in the skin, lungs, bladder and kidney. It can also cause other skin changes such as thickening and pigmentation. Black foot disease, (BFD) a form of peripheral vascular disease, has been reported to be one of the important complication of chronic arsenic toxicity(CAT) in Taiwan. [16,17].Exposure to arsenic in the workplace by inhalation can also cause lung cancer Non-malignant skin alterations, such as keratosis and hypo- and hyper-pigmentation, have been linked to arsenic ingestion. Removal technologies for Arsenic Contaminated Drinking water: There are several methods available for removal of arsenic from water in large conventional treatment plants. The most commonly used processes of arsenic removal from water have been described by Cheng and others (1994), Hering and others (1996), Hering and others (1997), Kartinen and Martin (1995), Shen (1973), and Joshi and Chaudhuri (1996)[18].

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Fig. 2.A keratosis victim

The basic principles of arsenic removal from water are based on conventional techniques of oxidation, coprecipitation and adsorption on coagulated flocs, adsorption onto sorptive media, ion exchange, and membrane filtration[19]. Oxidation of As(III) to As(V) is needed for effective removal of arsenic from groundwater by most treatment methods[20]. The most common arsenic removal technologies can be grouped into the following four categories: x x x x

Oxidation and sedimentation Coagulation and filtration Sorptive filtration Membrane filtration

The existing and emerging arsenic removal technologies are available including: x x x x x x x x x

Sorption on activated alumina Sorption on iron oxide coated sand Sand with zero-valent iron Cation exchange resins Anion exchange resins Coagulation with ferric ion Granulated iron oxide Nanomagnetite particles Reverse osmosis

Characteristics of Arsenic contaminated sludge: The physical characteristics of wastes generated by traditional As removal processes has been done by scanning electron microscopy equipped with energy dispersive X-ray spectrometer (SEM-EDX). Physical properties of sludge: Density of oven dried(105oC) sludge = 0.9 g/cc. Arsenic contain within sludge almost 4.2 kg/m3,and pH of the sludge variable from 5 to 8.

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Prasanta Mandal et al. / Procedia Environmental Sciences 35 (2016) 943 – 949 Table 1: Some chemical and physical characteristics of the sludge

Chemical composition of Arsenic sludge (wt.%)

Al2O3

SiO2

Fe2O3

CaSiO3

As

71.85

13.08

11.46

3.19

0.42

Fig. 3.SEM photographs of Arsenic sludge

Fig. 4. EDAX of Sludge

Disposal methods: Regeneration of activated alumina and ion exchange resins results in various semi liquid wastes that may be acidic, caustic, saline, and too arsenic rich for simple disposal. Hence, environmentally safe disposal of sludge, saturated media, and liquid wastes rich in arsenic is a concern. The EPA has developed a toxic characteristic leaching procedure (TCLP) test to identify wastes likely to leach toxic chemicals into groundwater[21,22]. The permissible level for TCLP leachate is generally 100 times higher than the maximum contaminant level in drinking water. Wastes with high concentration of arsenic may need solidification or confinement before final disposal. Arsenic rich sludge may be disposed by the following methods:

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x x x

Disposal in on-site sanitation pits/ landfill. Mixing with concrete in a controlled ratio. Mixing with clay for burning for brick manufacturing.

Disposal in on-site sanitation pits/ landfill: Groundwater constitutes 97% of all freshwater that is potentially available for human use. Groundwater is therefore of fundamental importance to human life. On-site sanitation systems can lead to contamination of groundwater sources. The contamination takes place in the event of a pathway existing between a source i.e. on-site sanitation system and a receptor[23]. Mixing with concrete in a controlled ratio: Another commonly used treatment is cement based solidification and stabilization (s/s). Cement is used to treat a large range of hazardous wastes by improving physical characteristics and decreasing the toxicity and transmission of contaminants.This process involves mixing the waste, either in form of sludge, liquid or solid, into a cementitious binder system[24]. However the effectiveness of As sludge treatment through s/s was strongly influenced by the type of As compound present. Arsenate has the lowest mobility[25]. It was found that Ca of cement influenced the leaching and immobilized As. With higher Ca:As molar ratio generally results in lower As leaching[26]. The enormous reduction of As concentration in cement-based immobilization was due to the formation of calcium biarsenate (CaHAsO3), which possesses a binding/cementing property, in the presence of Ca(OH)2[27,28]. The solidification and stabilization (S/S) technique with lime and Ordinary Portland cement (OPC) was successfully applied for the stabilization and environmentally safe disposal of arsenic contaminated sludge. Mixing with clay for brick manufacturing: The physical property requirements in most specifications are water absorption capacity, Saturation coefficient, Specific gravity, Specific Surface Area (SSA), optimum moisture content (OMC), Toxicity Characteristics Leaching Procedure (TCLP) using USEPA Method 131. It was observed that, with increase in percentage of sludge the compressive strength of the bricks decreases with all firing temperatures[29,30]. Stabilization of As-sludge using clay it was observed that up to 10% of clay (volume) was found to be safe[31]. As contaminated sludge could be used safely up to 4% only for making ornamental bricks and tiles [29]. Conclusions: Arsenic-contaminated water is a massive problem in the developing world. But, even when you filter it, the toxic sludge that the process produces often gets dumped right back into the water supply.Effective and reliable method for environmental safe disposal of arsenic contaminated sludge is a gigantic problem. U.S Environmental Protection Agency (USEPA) recognizes cementitious solidification as the “best demonstrated available technology (BDAT)” for land disposal of most toxic elements. Arsenic sludge technologies have improved significantly over the last few years but many of the technologies do not work satisfactorily. Reliable, cost-effective, and sustainable treatment technologies are yet to be identified and further developed. Acknowledgement: Authors are thankful to Director-CSIR-CMERI, Durgapur for supporting this work. References: 1)

2) 3)

Ali, M. A., Badruzzaman, A.B.M.,Jalil, A.B., Ahmed, M.F., Al-Masud, A., Kamruzzaman, M.,Rahman, A.R.( 2003) Fate of Arsenic in Wastes Generated from Arsenic Removal Units. In: M. F. Ahmed and others, eds., Fate of Arsenic in the Environment 147-160. Bangladesh University of Engineering and Technology and United Nations University. Arsenic in drinking water seen as threat. USAtoday.com, August 30, 2007. Banerjee, G., Chakraborty, R. (2005) Management of arsenic-laden water plant sludge by stabilization. Clean Techn Environ Policy 7:27078.

Prasanta Mandal et al. / Procedia Environmental Sciences 35 (2016) 943 – 949 4) 5) 6) 7) 8) 9)

10) 11) 12) 13) 14)

15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28) 29) 30) 31) 32)

Buchler, P., Hanna R.A., Akhter, H., Cartledge, F.K., Tittlebaum, M.E. (1996) Solidification/stabilization of arsenic: effects of arsenic speciation. Journal of Environ Sci Health—Part A 31:747–54. Chaurasia, N., Mishra, A., Pandey, S.K. (2012) Finger Print of Arsenic Contaminated Water in India-A Review. J Forensic Res 3:10. CPCB (19995-1996) Standards for liquid effluent, gaseous emission, automobile exhaust, noise and ambient air quality. Series PCL/4, Central Pollution Control Board, Ministry of Environment & Forest, Govt. of India. Dutre, V., Vandecasteele, C. (1995) Solidificationstabilization of arsenic-containing waste: leaching tests and behavior of arsenic in the leachate. Waste Manage 15:55 –62. Dutre, V., Vandecasteele, C. (1998) Immobilization mechanism of arsenic in waste solidified using cement and lime. EnvironlSci Technology 32(18):2782–87. Eriksen-Hamel, N., Zinia, N.K. ( 2001) A Study of Arsenic Treatment Technologies andLeaching Characteristics of Arsenic Contaminated Sludge. In: Ahmed, M. F., M. A. Ali, andZ. Adeel, eds., Technologies forArsenic Removal from Drinking Water207–213. BangladeshUniversity of Engineering & Technology and United Nations University. GuhaMazumder D.N. (1996)Health effect of arsenic in drinking water: problem in West Bengal and strategy. J Indian Med Assoc. 94(2). GuhaMazumder D.N. (2008) Chronic arsenic toxicity & human health. Indian J Med Res 128:436-447 Hopenhayn-Rich C., Biggs, M.L., Fuchs A., Bergoglio, R., Tello, E.E., Nicolli, H., Smith, A.H., (1996) Bladder cancer mortality associated with arsenic in drinking water in Argentina. Epidemiology 7:117-124 IPCS (2001) Arsenic and arsenic compounds. Second edition. World Health Organization, Geneva, Switzerland. Kerndorff, H., Schleyer, R., Milde, G., and Plumb Jr., R.H., (1992) Geochemistry of groundwater pollutants at German waste disposal sites. In: S. Lesage and R. Jackson (Eds.), Groundwater contamination and analysis at hazardous waste sites. Environmental Science and Pollution Control Series Vol. 4; pp. 245-271 Ko, I., Davis, A.P., Kim, J.Y., Kim, K.W. (2007) Arsenic Removal by a Colloidal Iron Oxide Coated Sand, J EnviornEngg, 891-98. Li, X.D., Poon, C.S., Sun, S., Lo, L.M.C. Kirk, D.W. (2001) Heavy metal speciation and leaching behaviors in cement based solidified/stabilized waste materials. Journal of Hazard Mater 82:215–30. Li, Y., Wang, J., Luan, Z., Liang, Z, (2010) Arsenic removal from aqueous solution using ferrous based red mud sludge.JHazard.Mater.177:131–137 Mahzuz ,H.M.A., Alam, R., Alam, M.N., Basak, R., Islam, M.S. (2009) Use of arsenic contaminated sludge in making ornamental bricks. International Journal of Environ Sci Technology 6(2):291-98. Maji, S.K., Pal, A., Pal, T. (2008) Arsenic removal from real-life groundwater by adsorption on laterite soil. J Hazard.Mater. 151:811–820. Mukherjee, A., Sengupta, M.K., Hossain, M.A.,Ahamed, S., Das, B., Nayak, B., Lodh, D., Rahman, M.M.,Chakraborti, D., (2006)Arsenic Contamination in Groundwater: A Global Perspective with Emphasis on theAsianScenario.J Health PopulNutr24(2):142-163. Nesbitt, H.W., Muir, I.J. (1998) Oxidation states and speciation of secondary products on pyrite andarsenopyrite reacted with mine waste waters and air. Mineral.Petrol.62:123– 144. Richardson, S., Vaughan, D.J.(1989) Arsenopyrite: a spectroscopic investigation of altered surfaces. Mineral.Mag. 53:223– 229. Rouf, M.A., Hossain, M.D. (2003) Effects of using arsenic-iron sludge in brick making, Fate of Arsenic in the Environment, Proceedings of the BUET-UNU International Symposium, Dhaka, Bangladesh 193-208. Roy, R., Sah, M.,Mazumdar, A., Ray, S.S., (2014) Recent advancement in arsenic adsorbents: A mini review.International J. of Res. Environ SciTechnologyISSN 2249–9695 Singh, R., Singh, S., Parihar, P., Singh, V.P.,Prasad, S.M., (2015) Arsenic contamination, consequences and remediation techniques: A review.Ecotoxicology and Environmental Safety 112: 247–270. Singh, T.S., Pant, K.K.,(2004) Equilibrium, kinetics and thermodynamics study for adsorption of As(III) on activated alumina, Sep. Purif. Technol. 36:139–147. Smedley, P.L., Edmunds, W.M., Pelig-Ba, K.B. ( 1996) Mobility of arsenic in groundwater in the Obuasi gold-mining area of Ghana: some implications for human health. Spec. Publ. - Geol. Soc. Lond. 113:163–181. Smedley, P.L.,Kinniburgh, D.G. (2002A review of the source, behaviour and distribution of arsenic in natural waters. Applied Geochemistry 17 (5): 517–568. doi:10.1016/S0883-2927(02)00018-5. Sorini, S.S. (1997) Leaching tests: Commonly used methods, examples of applications to coal combustion by-products and needs for the next generation. Laramie, Wyoming: Sullivan, C., Tyrer, M., Cheeseman, C.R., Graham, N.J.D. (2010) Disposal of water treatment wastes containing arsenic- A review. Sci. of the total Environ. 408: 1770-78. Western Research Institute. Wiles, C.C. (1987) A review of solidification/stabilization technology. Journal of Hazard Mater.14:5-21.

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