Evidence of Economically Sustainable Village-Scale

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Evidence of Economically Sustainable Village-Scale Microenterprises for Arsenic Remediation in Developing Countries Michael German, Todd A Watkins, Minhaj Chowdhury, Prasun Chatterjee, Mizan Rahman, Hul Seingheng, and Arup K. Sengupta Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.8b02523 • Publication Date (Web): 08 Jan 2019 Downloaded from http://pubs.acs.org on January 9, 2019

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Environmental Science & Technology

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Evidence of Economically Sustainable Village-Scale Microenterprises for Arsenic

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Remediation in Developing Countries

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Michael S. German A,B, Todd A. Watkins C, Minhaj Chowdhury B, Prasun Chatterjee D,

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Mizan Rahman E, Hul Seingheng F, and Arup K. SenGupta A,B,G*

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A Department

of Civil and Environmental Engineering, Lehigh University (USA, 18015); B

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WIST, Inc. (USA, 75063); C Department of Economics, Lehigh University (USA, 18015);

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D WIST

Water Solutions Pvt. Ltd. (Kolkata, 700039, India); E Drinkwell Bangladesh Ltd.

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(Motijheel, Dhaka, 1000, Bangladesh); F Institute of Technology of Cambodia (PO Box

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86, Russian Federation Blvd, Phnom Penh, 12100, Cambodia); G Society for

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Technology with a Human Face (STHF, NGO, Kolkata, 700061, India)

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Corresponding author: [email protected]; 1 W. Packer Ave, Bethlehem, PA

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18015; 610-758-6405 (fax); 610-758-3534 (office)

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TOC/Abstract Art

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1 ACS Paragon Plus Environment


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Abstract

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Although unknown 25 years ago, natural arsenic contamination of groundwater affects

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over fifty countries and up to 200 million people. The economic viability was analyzed and

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modelled of eighty-eight community-based arsenic mitigation systems existing for up to

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20 years in India and Bangladesh. The performances of three community-based arsenic

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mitigation systems that are ethnically different and separated across two different

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countries were monitored closely for 24 months of self-sustainable, long-term operation

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at WHO standards through local, paid caretakers.

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Based on data from the use of hybrid ion exchange materials (HIX-Nano) and the broad

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set of field operations, Monte Carlo simulations were used to explore the conditions

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required for self-sustainable operation and job creation in low-income communities

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(100 million people across rural India, Bangladesh, Nepal, Burma, Vietnam, Cambodia

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and Laos remain at high risk of drinking water well above the WHO arsenic limit (0.010

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mg/L).21-25 An additional 100 million people are at risk of high fluoride consumption (WHO

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limit: 1.5 mg/L) throughout the Indian subcontinent and East Africa after 40 years of

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treatment efforts.26,27 Although technological innovations are highly desirable for efficient

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removal of both arsenic and fluoride from contaminated groundwater, their integrations 3 ACS Paragon Plus Environment


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with the social and economic framework of the affected communities pose serious

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challenges. In 2010, Johnston et al. reviewed treatment systems in Bangladesh and noted

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that household-based treatment systems faced logistical and operational challenges and

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community-based systems faced financial sustainability challenges.28 In response, they

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recommended arsenic avoidance.29,30 and the controlled use of water from deep aquifers

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for non-agricultural applications.31-34 Water from deep aquifers does not necessarily

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eliminate the treatment requirement because many deep aquifers across the Indian

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subcontinent have been found with significant hardness, iron and salinity. One salient

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question that evolved during the same period was: Can a robust mitigation technology,

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combined with an appropriate economic model and villagers’ participation, including both

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men and women, transform the crisis into an economic opportunity? This inquiry and

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sustained follow-up efforts led to the installation of tens of community mitigation systems

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since 2000 through various forms of local and international collaborations.

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Community-Scale vs. Point of Use (PoU) Treatment

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Lacking strong central water governance, decentralized systems based on

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household point of use (PoU) treatment emerged as an acceptable option in arsenic-

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affected communities in South and Southeast Asia. However, coordinating consistent

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operation and collection of arsenic-laden sludge from individual families to ensure safe

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disposal posed insurmountable hurdles.26 In addition, the PoU model was deemed

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economical solely because all associated labor for its installation and day-to-day

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operation were considered free of cost. Consequently, this approach, where human labor

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was

never

compensated,

did

not

create

employment


opportunities

beyond

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manufacturing. Quality control and maintenance of the treated water in individual

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households posed major difficulty regarding concurrent iron and arsenic removal.26-30

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In comparison, centralized community-based village-scale water treatment

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systems designed to serve 100-200 families (i.e., 500-1000 individuals), can produce high

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quality water when operated by paid plant operators (caretakers) and water transported

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to individual households by delivery personnel. Net uncompensated labor hours are thus

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significantly reduced while new jobs are created in the community as shown in

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supplementary information (SI) Figure S1.38,39 Systems were managed by a village-

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selected committee comprising both men and women. Most importantly, every

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participating family was viewed as a stakeholder and required to pay a monthly tariff to

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cover the maintenance cost of the plant and compensation of the trained operator, as

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agreed by the villagers’ committee. Water delivery was a separate paid service that was

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highly valued for the elimination of the physical burden of carrying water over 500m. Key

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elements of the community-based systems are presented in Figure 1A, while Figure 1B

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exhibits one community-based system in existence with water delivery through local

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vehicles (e.g., rickshaw or tuk-tuk). The fundamental tenet of the economic model that

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evolved over a decade in arsenic-affected rural communities is that all human labor

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needed to sustain safe water supply must be financially compensated from tariffs received

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from participating villagers. Details and photographs of past, active arsenic treatment

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systems are included in SI Table S1.



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103


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Figure 1. A) A general overview of a sustainable, interconnected water system that can

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produce safe water with sustainable financial growth (top); B) One community treatment

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system with rickshaw delivery service of safe water to individual households in the Indian

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subcontinent (bottom).

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Choice and Implementation of Technology

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Activated alumina is a widely used adsorbent for both arsenic and fluoride but it

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suffers from the following major shortcomings: first, it is unable to remove As(III) or

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arsenite; second, it is chemically unstable at acidic and alkaline pH; and, third, it is not

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reusable for more than 1-2 cycles, thus generating hazardous waste in rural communities

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lacking proper solid waste management.38,39 Reverse Osmosis or RO is a non-specific

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treatment that requires continuous supply of electricity and discards 50-80% of the feed

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water as waste with elevated concentrations of arsenic and fluoride. From an

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environmental sustainability viewpoint, the Department of Drinking Water and Sanitation

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(DDWS) of the Government of India, now the Ministry of Drinking Water and Sanitation

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(MDWS), strongly discouraged indiscriminate use of RO to mitigate the arsenic and

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fluoride crisis.40 Other adsorbents, namely, granular ferric hydroxide/oxide (GFH or GFO),

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naturally occurring laterite and titanium dioxide doped chitosan are not amenable to reuse

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or not available commercially.41-44

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Hybrid ion exchangers or HIX-Nano materials are comprised of a polymeric anion

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exchange resin support that is dispersed with metal oxide nanoparticles (e.g., iron,

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zirconium) both within the macropores and the gel phase.45-50 HIX-Nano

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commercialized over a decade ago because of its synergy of high capacity, high

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reusability and consequent reduction in the cost of treated water for arsenic, fluoride and 7 ACS Paragon Plus Environment

was


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phosphate removal.38,39,44-52 Arsenic removed from groundwater is converted into solids

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(sludge) of ferric hydroxide that are contained over an aerated coarse filter under an

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oxidizing environment. Continued research and field-scale applications in India,

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Cambodia, Bangladesh and Nepal have created robust and simple-to-apply sludge

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containment protocols in rural communities to ensure environmental compatibility and

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public safety.50-60 In addition to robustness and high capacity, the reusability of HIX-Nano

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makes the process conducive to long-term application in developing countries due to

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lesser dependence on supply of the adsorbent material. Several community-based

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systems are in operation for more than a decade and HIX-Nano materials are now

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produced in India.

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The central goals of this investigation were to evaluate whether community-based arsenic mitigation systems in developing countries, once installed, can:

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i)

Operate long-term while generating positive operating earnings;

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ii)

Create employment opportunities in affected communities without outside subsidies;

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iii)

accordance with national/WHO standards;

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Operate and maintain HIX-Nano to achieve treated water quality in

iv)

Maintain self-sustaining operation in affected communities.

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ECONOMIC ANALYSIS METHODS A

cash-flow

model

of

community-based

systems

was

developed

for

microenterprise operations to account for process economics: capital expenses or CapEx 8 ACS Paragon Plus Environment

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[e.g., site preparation cost (S), HIX-Nano resin (R), system equipment (E), construction

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(C)]; wages (W); non-wage operational expenses including regeneration cost or OpEx

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[e.g., electricity expense (Z), operation and maintenance including chemicals (M), delivery

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(D), marketing (K), overhead (Ov)]; financial expense or FinEx [e.g., amount borrowed

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(B), loan interest rate (I), amortization term period (T)]; and revenue or REV [e.g., price

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of water (P), quantity of water processed (Q) and number of customers (N)].

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Net monthly cash flows (CFit), i.e., monthly operating profit or loss, in location i during month t, were then: CFit = REV(Pit , Nit) – {CapExit(Sit , Rit , Eit , Cit) + Wit + OpExit(Qit , Zit , Mit , Dit , Kit , Ovit) + FinExit(Bi , Ii , Ti)}

(1)

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Three critical sustainability questions are whether village communities can 1) have

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sustainable operational economics, i.e., monthly revenues exceeding monthly expenses;

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2) generate employment opportunities in affected communities; and, 3) can provide safe

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drinking water in compliance with the WHO standards without any significant violation.

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Operations are cash flow positive monthly when CFit > 0. Since monthly cash flows vary

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and are dependent on external factors like ambient weather, religious fasting and other

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similar constraints, cumulative cash flows (CCFit) over a two-year period is a more

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objective global indicator of sustainability and economic health of the community system

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and presented as follows: 𝑡

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𝐶𝐶𝐹𝑖𝑡 = ∑ 𝐶𝐹𝑖𝑡 𝑡=0

(2)



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Cumulative operating cash flows (COCFit) may be considered when CapEx is fully

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subsidized, i.e., government-funded installations, where CapExit is excluded from CFit

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calculations by starting time at t=1.

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Self-sustaining operations were explored via Monte Carlo analysis with 2000

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simulations in Palisade’s @RISK 56,57 under various scenarios to determine periodic cash

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flows and operational breakeven periods. Instead of making assumptions about variable

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parameter distributions and correlations58,59 among them, as is typical in Monte Carlo

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applications, financial data from actual system implementations was used to inform the

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input distributions and correlations. Probability distributions for key input variables in the

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cash flow simulations (CapEx, W, non-wage OpEx, P, N, Q, B, I, T) were best fit

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distributions from data collected, in some cases for more than a decade, at nine HIX-

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based arsenic treatment systems in India and Bangladesh (a total of 103 observations)

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or from national surveys (W, I),62 as shown in SI Figure S2A-E. Additionally, price and

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quantity data was also collected for seventy-nine further sites (Table S1), and used to

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inform correlations.

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Community-Based Systems Investigated and Other Input Data

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Three community-based treatment systems in arsenic affected rural communities,

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namely, Ballia, Manikganj and Supaul, were specifically identified for detailed analysis in

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the present study; they were part of the eighty-eight total systems used for Monte Carlo

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modelling. These three communities are geographically far apart from each other and

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ethnically different.


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Ballia (25°44'27.2"N 84°18'27.9"E) is a district in the most populous state of Uttar

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Pradesh in India, along the bank of the River Ganges. The entire district is affected by

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widespread arsenic contamination of groundwater and confronted with adverse health

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impacts on rural population. In 2013, the Society for Technology with a Human Face or

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STHF (NGO) installed a community-based treatment system using HIX-Nano as the

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primary sorbent.

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Manikganj (23°30'28.4"N 90°13'15.2"E) is one of the arsenic affected districts in

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Bangladesh with hundreds of defunct household PoU systems. In February 2015, an HIX-

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Nano system was installed in Manikganj with the support of STHF and WIST, Inc.

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Although Bangladesh is the worst arsenic-affected country, Manikganj has been the

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longest-running community-based arsenic treatment system there.

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In Supaul, Bihar, India (26°05'14.2"N, 86°30'30.7"E), STHF installed an HIX-Nano

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community drinking water system in late 2015 to remove arsenic and iron at a community

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toilet block operated by Sanitation and Health Rights in India (SHRI, NGO). SHRI

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purchased the system to use water sales revenue to offset operational costs of their toilet

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block.

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These three low income communities (

Evidence of Economically Sustainable Village-Scale

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