Subscriber access provided by University of Florida | Smathers Libraries
Article
Safely managed sanitation for all means fecal sludge management for at least 1.8 billion people in low and middle income countries David M. Berendes, Trent A. Sumner, and Joe M. Brown Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.6b06019 • Publication Date (Web): 27 Jan 2017 Downloaded from http://pubs.acs.org on February 7, 2017
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Environmental Science & Technology is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 28
Environmental Science & Technology
1
Safely managed sanitation for all means fecal sludge management for at least 1.8 billion
2
people in low and middle income countries
3
David M. Berendes*1, Trent A. Sumner1, Joe M. Brown1
4
1
5
Georgia, USA; *corresponding author (email:
[email protected]; address: 311 Ferst
6
Dr. #3368, Atlanta, GA, 30332; phone: 404-894-3317; fax: 404-894-2278)
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta,
7 8
Abstract
9
Although global access to sanitation is increasing, safe management of fecal waste is a rapidly
10
growing challenge in low- and middle-income countries (LMICs). The goal of this study was to
11
evaluate the current need for fecal sludge management (FSM) in LMICs by region, urban/rural
12
status, and wealth. Recent Demographic and Health Survey data from 58 countries (847,685
13
surveys) were used to classify households by sanitation facility (facilities needing FSM, sewered
14
facilities, ecological sanitation/other, or no facilities). Onsite piped water infrastructure was
15
quantified to approximate need for wastewater management and downstream treatment. Over all
16
surveyed nations, 63% of households used facilities requiring FSM, totaling approximately 1.8
17
billion people. Rural areas had similar proportions of toilets requiring FSM as urban areas. FSM
18
needs scaled inversely with wealth: in the poorest quintile, households’ sanitation facilities were
19
almost 170 times more likely to require FSM (vs. sewerage) than in the richest quintile. About
20
one out of five households needing FSM had onsite piped water infrastructure, indicating
21
domestic or reticulated wastewater infrastructure may be required if lacking for safe management
22
of aqueous waste streams. FSM strategies must be included in future sanitation investment to
23
achieve safe management of fecal wastes and protect public health.
ACS Paragon Plus Environment
1
Environmental Science & Technology
Page 2 of 28
24
ACS Paragon Plus Environment
2
Page 3 of 28
Environmental Science & Technology
25
Introduction
26
While progress toward meeting the Millennium Development Goal (MDG) target for sanitation
27
fell short in 2015—an estimated 2.4 billion people still lack access to improved sanitation1—
28
significant expansion in global coverage has been achieved in the MDG era, and investment
29
continues to reduce open defecation and expand access to safer sanitation facilities. Sustainable
30
Development Goal (SDG) 6 goes further,2 explicitly recognizing the normative goal of “safely
31
managed” sanitation in addition to coverage, highlighting the importance of safe excreta disposal
32
to reduce health risks. This shift is also reflected in refinements to the “sanitation ladder”
33
approach adopted by the Joint Monitoring Program (JMP), explicitly focusing on the safe
34
management of fecal wastes to reduce downstream exposures.1
35
Wastewater management—the removal of fecal wastes through water-based transport to
36
downstream treatment and disposal (e.g. piped networks like conventional sewerage)—has been
37
practiced as the normative standard for management of fecal waste since the mid-1800’s in urban
38
areas, where population density creates economies of scale.3 Fecal sludge management (FSM)—
39
the on-site management of fecal biosolids with generally lower water content—is a challenge
40
with new visibility in the urban sanitation sector in low and middle-income countries (LMICs).4
41
The advent of fecal waste flow diagrams and sanitation mapping exercises have revealed the
42
global predominance of on-site sanitation (dry or pour-flush latrines), even in settings where high
43
population density might justify reticulated sewerage.5,6 Many sanitation facilities available to
44
both the urban and rural poor require FSM to adequately sequester fecal wastes: a delayed, rather
45
than immediate, problem. The apparent global need for FSM services may be partly attributable
46
to the metrics-driven focus on expansion of toilets to increase coverage and reduce open
47
defecation, justifiably apriority in meeting immediate sanitation needs. More latrines, however,
ACS Paragon Plus Environment
3
Environmental Science & Technology
Page 4 of 28
48
leads to concentration of wastes that must be safely managed to protect public health. FSM has a
49
tendency to be forgotten during and after infrastructure is built.7,8
50
Many households in LMICs have sanitation facilities requiring FSM services7 Despite
51
FSM’s central importance to the functionality, impact, and sustainability of global sanitation
52
infrastructure, no estimate of the worldwide need for FSM services is available. An accounting
53
of how many households require FSM is an essential step in the effort to ensure sanitation
54
infrastructure and services deliver the greatest possible health impact under the SDGs. Such
55
estimates are also valuable for advocacy, targeting FSM programs, and stimulating interest in
56
developing better FSM technologies and services to meet growing needs as sanitation coverage
57
expands.
58
This study examined the worldwide prevalence of households using sanitation facilities
59
requiring FSM based on recent Demographic and Health Survey (DHS) data from 58 LMICs.
60
We assessed the types of sanitation facilities reported to be used by households by World Health
61
Organization (WHO) region, urban/rural status, and wealth quintile to quantify the current
62
prevalence of sanitation facilities requiring FSM to function safely and to understand how this
63
prevalence varies across key population segments. We also estimated the proportion of facilities
64
reportedly used by households connected to water supplies to inform future demand for
65
wastewater management. This research will contribute to quantifying inequalities in the need for
66
FSM and wastewater management in LMICs worldwide, an explicit focus of the SDGs in
67
addressing sanitation needs for the poorest of the poor.2
68 69
Methods
70
Data sources
ACS Paragon Plus Environment
4
Page 5 of 28
Environmental Science & Technology
71
Data for this study were extracted for analysis from the Demographic and Health Survey (DHS)
72
program from Phase 5 (2003-2008), 6 (2008-2013), and 7 (current, 2013-2018: the most recent
73
survey was from 2015) surveys. DHS surveys are country-specific and if a country had more
74
than one survey within the Phase 5-7 period, only the most recent survey data were analyzed.
75
DHS methodology generally involves two-stage sampling: selection of enumeration
76
areas/clusters followed by selection of households.9 Household questionnaires ask about
77
numerous topics, including water and sanitation. Questions about the kind of toilet facility used
78
by the members of the household and the main source of drinking water for the household were
79
the focus of this analysis. Further, information about urban or rural location of the household and
80
wealth were obtained from each survey. Wealth indices were country-specific and based on
81
household assets and utilities, which were weighted by the DHS program using principal
82
components analysis. These index scores were then grouped into country-specific wealth
83
quintiles based on household population figures from the survey.10
84
Classification of DHS Sanitation and Drinking Water Source Questions
85
DHS questions about the sanitation facility (DHS question 109 in Phase 7 survey11) and type of
86
drinking water source (DHS question 101 in Phase 7 survey11) were used to classify households’
87
need for fecal sludge management (FSM) or wastewater management. First, households’
88
responses to the type of sanitation facility usually used were classified into four categories: 1)
89
use of facilities connected to sewerage or sewers—any response listing connection to sewered or
90
piped system (“Sewered”); 2) use of facilities that were composting toilets, associated with
91
composting facilities, “other”, or no response (“Other/EcoSan”); 3) no use of facilities (“No
92
facility”); and 4) use of facilities that retain waste onsite (latrines connected to septic tanks and
93
subsurface discharge or pits) or discharge waste onsite (latrines with surface discharge) and
ACS Paragon Plus Environment
5
Environmental Science & Technology
Page 6 of 28
94
therefore must be managed onsite (“FSM needed”). Second, households’ responses to reported
95
drinking water source were grouped into 4 categories based on location and type of infrastructure
96
associated with the source: 1) drinking water sources that were piped into the household or plot
97
(“On-premises piped connections ”, though the source may not have been onsite); 2) sources that
98
were onsite, but not piped, or were present at a neighbor’s house (“Other on-
99
premises/neighbor”); 3) sources that were not listed as onsite or at a neighbor’s house (“Not on-
100
premises”); and 4) other/no response (“Other”). Responses from both of these questions allowed
101
broad categorization of households by potential need for wastewater vs. FSM based on the type
102
of sanitation facility and piped water infrastructure present. On-premises water supply, in
103
combination with sanitation facilities, was used to indicate potential current or future demand for
104
pour-flush or flush latrines using water to convey waste, and therefore higher wastewater
105
volumes and need for access to septic systems with safe discharge (low population density) or
106
sewerage (high population density).
107
The proportions of households per country in each category were calculated using
108
complex survey weighting to account for the two-stage cluster survey techniques used in the
109
DHS.9,12 Households not responding to these questions were included in the denominator to
110
ensure accurate survey weighting and population estimates (see below). Households were further
111
divided by urban/rural status and wealth quintile. Use of sanitation facilities was quantified 1)
112
among all households, (including those with no access to sanitation); and 2) among only those
113
households reporting using sanitation facilities (to better describe FSM needs among those with
114
current access to a sanitation facility).
115
Population estimation
116
The most-recent (2016) country-level population estimates from the Central Intelligence
ACS Paragon Plus Environment
6
Page 7 of 28
Environmental Science & Technology
117
Agency (CIA) Factbook13 were multiplied by the weighted proportions of households in each
118
category to estimate the total population in each category.
119
Analysis Data were analyzed from 847,685 surveys from 58 countries across all six World Health
120 121
Organization (WHO) regions: 33 countries in Africa, 7 in Latin America and the Caribbean
122
(“LAC”), 6 each in Europe and Southeast Asia, and 3 each in the Eastern Mediterranean (“E.
123
Med.”) and Western Pacific (Table 1). The total estimated population across the 58 countries in
124
the analysis was 3,205,819,618, representing 44% of the global population and 54% of the
125
population residing in LMICs as defined by the United Nations.14 All analyses were conducted in
126
R version 3.2.1 using base packages, as well as the “lme4” package for mixed-effects logistic
127
regression and the “survey” package for complex survey weighting.15–18 Mixed-effects logistic
128
regression models were used to quantify the magnitude of associations between a) drinking water
129
location, b) urban/rural status, and c) wealth quintile; and the reported use of a sanitation facility
130
that required FSM to function (compared to those connected to sewerage). Random effects for
131
country of the survey, as well as enumerations areas within each country, were included in the
132
model.
133 134
Results
135
FSM requirements among surveyed nations
136
The average prevalence and total population of households that reported using different
137
categories of sanitation facilities (connected to sewerage vs. those in need of FSM vs. no facility)
138
were calculated by country. Prevalence estimates were then averaged by WHO region and across
139
all countries surveyed, with estimated populations summed (Table 1). Over all countries
ACS Paragon Plus Environment
7
Environmental Science & Technology
140
surveyed, an average of 63% of all households reported using sanitation facilities in need of
141
FSM, summing to almost 1.8 billion people out of the 3.2 billion people currently living in the
142
included countries (56%). The population-level need for FSM was greatest in Africa (mean of
143
65% of households, summing to 577 million people) and Southeast Asia (mean of 61% of
144
households, summing to 816 million people), though the Western Pacific had the highest mean
145
proportion of households reporting using facilities requiring FSM (74%).
146
To assess the need for FSM among households with current access to a sanitation facility,
147
we conducted a separate analysis of the prevalence and population of households that reported
148
using facilities in need of FSM among only those that reported using a sanitation facility.
149
Overall, 81% reported using sanitation facilities needing FSM, with over half of households
150
reported using sanitation facilities that needed FSM in all regions (data not shown). The largest
151
average figures were in the Western Pacific (94%), Africa (90%), and Southeast Asia (81%),
152
followed by LAC (63%), E. Med. (56%), and Europe (60%). Notably, almost 22% (more than 1
153
billion people) of households in surveyed nations did not use a facility currently.
154
Overall, an average of about one-quarter of households (26%) reported using on-premises
155
piped connections to water sources (693 million people). Few households (< 2% on average)
156
reported using other on-premises or a neighbor’s water sources, while most (70% on average,
157
summing to over 2.3 billion) reported using an off-premises drinking water source.
158
FSM needs in urban and rural areas in surveyed countries
159
Page 8 of 28
The average proportions of households reporting using sanitation facilities needing FSM
160
were similar in urban (66%) and rural (65%) areas, though the urban population-level need was
161
lower (735 million) when compared with the rural areas (1 billion, Table 2). Among households
162
that did not report using sanitation facilities needing FSM, the majority (79%, 248 million) in
ACS Paragon Plus Environment
8
Page 9 of 28
Environmental Science & Technology
163
urban areas reported using sewered facilities, while the majority (89%, 959 million) in rural areas
164
did not report using a facility. A larger average proportion reported using sanitation facilities
165
needing FSM in urban areas, compared with rural areas, in the African region (78% vs. 60%) and
166
W. Pacific region (80% vs. 73%). However, the size of the population that reported using
167
facilities in need of FSM was generally higher in rural areas than in urban areas. Over 2.5 times
168
more people reported using facilities in need of FSM compared with sewerage in urban areas
169
(735 million vs. 285 million), while over 30 times more people reported using facilities in need
170
of FSM compared with sewerage in rural areas (1 billion vs. 32 million).
171
Among only households that reported using sanitation facilities, an average of 72% in
172
urban areas and 91% in rural areas reportedly used facilities that need FSM to function (data not
173
shown). This proportion was more variable by region in urban areas (range: 30 – 86%) compared
174
with rural areas (range: 76 – 98%). The African (86%), W. Pacific (83%) and Southeast Asian
175
(67%) regions had the largest urban proportions. In contrast, rural areas of all regions, with the
176
exception of LAC, had at least 88% of households using facilities needing FSM.
177
FSM needs by wealth quintile in surveyed countries
178
While the need for FSM appeared to be unrelated to wealth quintile across all households,
179
among households that reported using sanitation facilities (thus excluding households without
180
access to sanitation facilities, the need for FSM scaled with poverty (Table 3). For example, in
181
the richest households, an average of 64%—representing 66% of households that reported using
182
sanitation facilities (data not shown)—reported using sanitation facilities needing FSM services.
183
In contrast, in the poorest households, 50%—representing 92% of households that reported using
184
sanitation facilities—reported using sanitation facilities needing FSM services. Almost 47% of
185
the poorest households did not report using a sanitation facility.
ACS Paragon Plus Environment
9
Environmental Science & Technology
186
Page 10 of 28
By population, about 2.5 times more people reportedly used facilities needing FSM than
187
sewerage in the richest quintile (457 million vs. 177 million), while almost 75 times more people
188
reportedly used facilities needing FSM than sewerage in the poorest quintile (209 million vs. 2.8
189
million). Though the proportion of households that reported using facilities needing FSM in each
190
wealth quintile was generally higher in rural areas than in urban areas, the trend of increasing
191
need for FSM from richest to poorest households among households reporting using sanitation
192
facilities was consistent between rural and urban areas (data not shown).
193
FSM needs and wastewater management potential by region among surveyed nations
194
To estimate the potential for wastewater management (in contrast to FSM), reported use
195
of “on-premises piped connections” for drinking water (from measurement of the location of a
196
household’s reported drinking water source) was used as an indicator of potential preference for
197
or possibility of flush toilets (and subsequent need for additional reticulated or domestic
198
wastewater infrastructure such as sewerage or subsurface discharge of septic effluent, Table 4).
199
Overall, an average of 69% of households with on-premises, piped connections to drinking water
200
sources reported using sanitation facilities in need of FSM to function, representing over 381
201
million people (about 22% of the almost 1.8 billion in need of FSM). These population figures
202
were highest in Southeast Asia (191 million), Africa (almost 76 million), and the Western Pacific
203
(43 million). In the Western Pacific, 93% of households with onsite, piped drinking water
204
reported using sanitation facilities in need of FSM to function. Of note, almost 100 million
205
people reported using sewered sanitation facilities, but reported having a drinking water source
206
that was not on the premises.
207
Households’ wastewater management and FSM needs were further divided by urban/rural
208
areas and wealth (Table 5). About two-thirds (259 million) of the 384 million who reported using
ACS Paragon Plus Environment
10
Page 11 of 28
Environmental Science & Technology
209
both on-premises piped connections for drinking water and sanitation facilities in need of FSM
210
were in urban areas. However, an average of 78% of households in rural areas with on-premises
211
piped connections for drinking water reported used sanitation facilities in need of FSM. Overall,
212
when moving down in wealth quintile in each water category, the proportion of households that
213
reported using sewered facilities decreased and the proportion reportedly not using a facility
214
increased, similar to previous observations.
215
When examining only households that reported using sanitation facilities by wealth
216
quintile and drinking water location, both drinking water location and management of the
217
sanitation facility varied with wealth. Among the richest, 128 million (21%) reported using both
218
on-premises piped connections for drinking water and sewered facilities, another 187 million
219
(31%) reported using on-premises piped connections but used sanitation facilities in need of
220
FSM (as well as 48 million reportedly using sewered facilities without on-premises piped
221
connections), and 246 million (40%) did not report on-premises piped connections and needed
222
FSM for their sanitation facilities. However, among the poorest, there was very little reported use
223
of 1) both on-premises piped connections for drinking water and sewered facilities (1 million,
224
0.5%); or 2) on-premises piped connections with sanitation facilities in need of FSM (15 million,
225
8%). Instead, the majority (180 million, 91%) lacked on-premises piped connections and needed
226
FSM for their sanitation facilities.
227
Multivariate modeling of drinking water location, household location, and wealth on FSM need
228
within surveyed nations
229
To understand the magnitude of associations between drinking water location, household
230
location (urban/rural status), wealth, and the need for FSM, mixed-effects logistic regression was
231
used to model sanitation facilities needing FSM relative to those that were sewered among
ACS Paragon Plus Environment
11
Environmental Science & Technology
Page 12 of 28
232
households reporting using sanitation facilities. Nested random effects were included for the
233
country and sub-country enumeration areas of each survey. Estimates of odds of needing FSM
234
(vs. having sewerage) are presented with 95% confidence intervals for the single, multivariate
235
model in Table 6. Households that reported using on-premises piped connections for drinking
236
water were half as likely to report using a sanitation facility in need of FSM compared to those
237
with water sources that were not onsite. Households in urban areas were 90% less likely to report
238
using sanitation facilities needing FSM compared with those in rural areas. Finally, the odds of
239
reporting using a sanitation facility needing FSM increased exponentially with decreasing wealth
240
quintile (increasing relative levels of poverty). Compared with the richest households, those in
241
the next lower quintile were 2.7 times more likely to report using a sanitation facility in need of
242
FSM, while those in the poorest wealth quintile were almost 170 times more likely.
243 244 245
Discussion The goal of this study was to estimate the current global use of sanitation facilities
246
requiring fecal sludge management (FSM) to continue to function, as well as divided by region,
247
urban/rural setting, wealth, and presence or absence of on-premises piped connections for
248
drinking water (an indicator of waste stream type and potential mobility of fecal waste). Among
249
the 58 countries included in this analysis, almost 1.8 billion people (56%) reported using
250
sanitation facilities requiring FSM to function properly, with the highest needs in rural areas.
251
Among households reporting using sanitation facilities, the poorest were also most likely to use
252
facilities in need of FSM, indicating an under-recognized disparity (beyond the 47% in this
253
quintile without access to sanitation facilities) that places additional burden on poor households
254
seeking to safely manage fecal waste. Discrepancies between the prevalence of on-premises
ACS Paragon Plus Environment
12
Page 13 of 28
Environmental Science & Technology
255
piped connections for drinking water and that of sewered sanitation indicate opportunities for
256
potential wastewater infrastructure expansion, distinct from FSM as it is usually understood
257
(manual or mechanical extraction, transport, and disposal of latrine waste biosolids).
258
Although previous estimates of improved sanitation categories exist1, this study is the first
259
to quantify the magnitude of the population using sanitation facilities in need of onsite FSM at a
260
global scale and to evaluate these needs by wealth equality and urban/rural status, both important
261
covariates when informing global, national, and local policy targets and service delivery
262
models.19 Further, use of on-premises piped drinking water infrastructure as a proxy for potential
263
wastewater management, in lieu of FSM, recognizes that fecal waste management strategies
264
depend on the waste stream characteristics, which may change given that rapid expansion of on-
265
premises water service may increase wastewater volumes faster than FSM service delivery can
266
adapt. The evidence in this manuscript improves the resolution of recent global estimates of
267
improved sanitation coverage by the JMP, WHO, and UNICEF1 and geographic inequalities in
268
access to improved facilities20—both of which have not quantified FSM and sewerage needs
269
separately—in preparation for monitoring the SDGs.2,21
270
Within the 58 countries with recent DHS data (2003 – 2015), almost 1.8 billion people
271
reported using sanitation facilities that require FSM—representing over 80% of the sanitation
272
facilities in LMICs. Though likely an underestimate of the true population-level need worldwide
273
due to countries excluded from this analysis, the prevalence of FSM needs vs. sewered sanitation
274
facilities underscores the discrepancy in expenses faced by non-governmental organizations,
275
local governments, and communities between these sanitation technologies. Many reasons,
276
including the almost 40-fold higher initial costs of sewerage, previous emphasis on coverage of
277
sanitation facilities, the lack of immediate need for FSM associated with installing sanitation
ACS Paragon Plus Environment
13
Environmental Science & Technology
Page 14 of 28
278
infrastructure, and the unsuitability of water-based sewerage systems in certain contexts,
279
contribute to sanitation facilities that contain waste onsite being much more prevalent than those
280
connected to sewerage worldwide.22–24,6 While onsite containment may safely separate fecal
281
waste from human contact immediately after being built, the sustained functionality and usability
282
of these facilities depends on management of the sludge: a large logistical and time burden for
283
users.22,25 Access, availability, cost, and reliability of FSM emptying services are highly variable
284
worldwide, depending on a range of locally specific factors.24,26–29 In contrast to areas already
285
piped for sewerage, areas with facilities in need of FSM incur logistical, financial, and
286
governmental challenges.6,30,31 Recent studies in large cities of LMICs have indicated that
287
governmental organization of FSM is generally poor, making sustained, reliable FSM
288
difficult.6,32 With the renewed focus on safe management of fecal sludge along the entire
289
sanitation chain in the SDGs, local governments must begin to include longer-term
290
considerations of the management of fecal sludge with existing demands for growth of sanitation
291
coverage.1,2
292
The need for FSM is not restricted to urban areas, where much of the research has been
293
focused, but instead is just as prevalent in rural populations.5,6,33 In contrast to the division
294
between sewered and unsewered facilities in urban areas, households in rural areas lacked
295
sewerage (likely due to infrastructural constraints in connecting households) and thus only
296
reported using unsewered facilities, if they reported using a facility at all.23 Despite rural areas
297
having more space to dig new pits than urban areas, they face other FSM needs in the form of
298
poorer availability of knowledge, training, and resources sufficient for the user to construct a
299
new collection area (i.e. dig a new pit), safely cover the old pit, and move the superstructure.29
300
Further, in many rural areas of the world, including India, water-based sanitation is a cultural
ACS Paragon Plus Environment
14
Page 15 of 28
Environmental Science & Technology
301
necessity, which therefore requires homes to have septic tanks or other onsite collection tanks,
302
increases the volume of sludge in the tanks, and necessitates conventional emptying similar to
303
urban areas.34,35 Thus, there is a need to provide for the technical aspects and logistics of facility
304
maintenance—either through separate services or in trainings to the user themselves—as part of
305
sanitation facility construction in rural areas.36
306
The costs of FSM needs are unequally distributed across the wealth spectrum due to
307
geographic inequities in infrastructure and differences in the financing and payment structures
308
between sewerage and FSM. Areas with sewerage are generally more expensive to live in, yet
309
have the benefit of wastewater management included in the cost or otherwise borne, in large part,
310
by the utility.22,29,37 In contrast, financial structures for FSM pass the majority of costs on to the
311
users themselves—up to 84% of the annual operating costs compared to 6% for sewered systems
312
in previous literature from Dakar, Senegal.22 These costs, by themselves, constitute a large
313
portion (almost 5%) of household income in the poorest neighborhoods and often are borne in
314
the form of one-time payments, rather than monthly installments.22,38 These financial concerns—
315
with the logistical burden associated with unreliable service—may force the poorest users to
316
either empty the waste themselves or abandon regular management of their sanitation facilities,
317
contaminating the local environment with fecal pathogens and increasing subsequent health
318
risks.22,25,39 In addition to their own fecal sludge, the fecal sludge of others further ‘upstream’
319
may impact the exposure of low-income households, for example in urban informal settlements,
320
with annual flooding, exacerbating health risks.40–43
321
A limitation of this study is that the need for FSM was assessed based on the standard DHS
322
sanitation metric, a self-reported measure that largely focuses on where defecation occurs, rather
323
than the final fate of the household’s fecal sludge, in the most recent DHS data available for each
ACS Paragon Plus Environment
15
Environmental Science & Technology
Page 16 of 28
324
country. There is a need to develop more comprehensive, rapid, feasible, and potentially risk-
325
based assessments of sanitation facilities and FSM to measure safe containment along the entire
326
sanitation chain.44
327
Further, these data give no indication of the composition of fecal sludge biosolids, current
328
availability of FSM services, functionality of sewerage, or the final treatment of the fecal sludge
329
in either case, limiting conclusions about the overall safety of the sanitation system present or the
330
potential for unmet demand for FSM services. While on-premises piped connections were used
331
to estimate potential need for strategies addressing more aqueous wastewater streams, the finding
332
that 100 million people used sewered sanitation yet lacked on-premises water connections
333
suggests a need for further investigation. Also, it is important to note that fecal waste transported
334
by sewerage may remain untreated in its final fate in many cases, thus sewerage – like other
335
FSM strategies - does not guarantee safe sanitation that precludes downstream human
336
exposure.45 Estimates of service provision from a study of 12 cities throughout four of the six
337
WHO regions suggest that a majority of fecal waste in onsite systems is not safely managed (61-
338
72% in Africa, 62-68% in LAC, 100% in SE Asia, and 5-100% in W. Pacific, the region with the
339
most variation) and in only 1/12 cities were 100% of sewered systems considered safely
340
managed.6 These data represent selected urban areas and thus there is a need for more active
341
research in quantifying current levels of service provision, including in rural areas.
342
While the construction and maintenance costs of sanitation facilities in need of FSM may
343
be lower for the implementer and FSM systems may be more sustainable than water-based
344
sewerage in the long term, their costs need to be included in the sanitation costs associated with
345
achieving the SDGs.22 The need for FSM is growing, both with the future expansion of sanitation
346
coverage to the more than 1 billion people in surveyed nations without a facility and with the
ACS Paragon Plus Environment
16
Page 17 of 28
Environmental Science & Technology
347
filling of pits and septic tanks of the almost 1.8 billion people currently served by sanitation
348
facilities in need of FSM. Further, increasing coverage of piped water infrastructure supplying
349
greater volumes of water to households will likely result in higher prevalence of water-based
350
flush toilet use. Local water provision can therefore change the nature of fecal waste streams,
351
resulting in greater volumes of more mobile waste requiring wastewater conveyance and
352
treatment. More aqueous waste may change technology choice and drive sanitation infrastructure
353
development. Given the interconnections between water and sanitation infrastructure expansion,
354
a systems approach to ensure safe management of fecal waste may be helpful to sustain both
355
human and environmental health.46
356
The current need of FSM worldwide is large and inequitably distributed amongst the
357
poorest households in both rural and urban areas. Existing piped water networks suggest that the
358
infrastructure for wastewater management may be present for about one out of every five people
359
with sanitation facilities without sewerage; however, for the rest of the population, financially-
360
sustainable and logistically-feasible business models for reliable, safe FSM services are needed.
361
In all, both wastewater management and FSM represent the next challenge in sanitation service
362
provision to ensure that the sustainable development goals are met and thus improve human
363
health and well-being.
ACS Paragon Plus Environment
17
Environmental Science & Technology
364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
Page 18 of 28
References (1) (2) (3) (4) (5)
(6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20)
(21) (22)
(23)
WHO and UNICEF. 2015 Update and MDG Assessment. 2015. United Nations. Transforming our world: The 2030 agenda for sustainable development; 2015. United Nations Centre for Human Settlements. The Design of Shallow Sewer Systems; Nairobi, 1986. Burian, S. J.; Nix, S. J.; Pitt, R. E.; Durrans, S. R. Urban Wastewater Management in the United States: Past, Present and Future. Jounal Urban Technol. 2000, 7 (3), 33–62. Peal, A.; Evans, B.; Blackett, I.; Hawkins, P.; Heymans, C. Fecal sludge management (FSM): analytical tools for assessing FSM in cities. J. Water, Sanit. Hyg. Dev. 2014, 4 (3), 371. Peal, A.; Evans, B.; Blackett, I.; Hawkins, P.; Heymans, C. Fecal Sludge Management : a comparative analysis of 12 cities. J. Water, Sanit. Hyg. Dev. 2014, 4 (4), 563–575. Koné, D. Making urban excreta and wastewater management contribute to cities ’ economic development : a paradigm shift. Water Policy 2010, 12, 602–610. Chunga, R. M.; Ensink, J. H. J.; Jenkins, M. W.; Brown, J. Adopt or adapt: Sanitation technology choices in urbanizing Malawi. PLoS One 2016, 11 (8), 1–16. ICF International. Demographic and Health Surveys Sampling and Household Listing Manual; 2012. Rutstein, S. O.; Johnson, K. The DHS Wealth Index. DHS Comp. Reports No. 6 2004, 1– 71. The Demographic and Health Survey Program; United States Agency for International Development. 2016 DHS household survey questionnaire; 2016. Vanderelst, D.; Speybroeck, N. Loading, merging and analysing demographic and health surveys using R. Int. J. Public Health 2014, 59 (2), 415–422. Central Intelligence Agency. The World Factbook: Country Comparison:: Population. United Nations. World Population 2015; New York, 2015. R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing: Vienna, Austria 2015. Bates, D.; Maechler, M.; Bolker, B.; Walker, S. Fitting Linear Mixed-Effects Models Using lme4. J. Stat. Softw. 2014, 67 (1), 1–48. Lumley, T. survey: analysis of complex survey samples. 2016. Lumley, T. Analysis of complex survey samples. J. Stat. Softw. 2004, 9 (1), 1–19. Mehta, M.; Knapp, A. The Challenge of Financing Sanitation for Meeting the Millennium Development Goals for Meeting The Millennium Development; 2004. Pullan, R. L.; Freeman, M. C.; Gething, P. W.; Brooker, S. J. Geographical Inequalities in Use of Improved Drinking Water Supply and Sanitation across Sub-Saharan Africa: Mapping and Spatial Analysis of Cross-sectional Survey Data. PLoS Med. 2014, 11 (4). WHO; UNICEF. JMP green paper: global monitoring of water, sanitation and hygiene post-2015. 2015. Dodane, P.-H.; Mbéguéré, M.; Sow, O.; Strande, L. Capital and operating costs of fullscale fecal sludge management and wastewater treatment systems in Dakar, Senegal. Environ. Sci. Technol. 2012, 46 (7), 3705–3711. Fry, L. M.; Mihelcic, J. R.; Watkins, D. W. Water and nonwater-related challenges of achieving global sanitation coverage. Environ. Sci. Technol. 2008, 42 (12), 4298–4304.
ACS Paragon Plus Environment
18
Page 19 of 28
410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455
Environmental Science & Technology
(24)
(25)
(26)
(27) (28) (29)
(30) (31)
(32)
(33) (34) (35) (36)
(37)
(38) (39)
(40)
Bassan, M.; Brdjanovic, D.; Dangol, B.; Dodane, P.-H.; Hooijmans, C. M.; Manuel Lopez-Vazquez, C.; Mbeguere, M.; Mikhael, G.; Moya Diaz-Aguado, B.; Niwagaba, C. B.; et al. Faecal Sludge Management; Strande, L., Ronteltap, M., Brdjanovic, D., Eds.; IWA, 2014. Jenkins, M. W.; Cumming, O.; Scott, B.; Cairncross, S. Beyond “improved” towards “safe and sustainable” urban sanitation: assessing the design, management and functionality of sanitation in poor communities of Dar es Salaam, Tanzania. J. Water, Sanit. Hyg. Dev. 2014, 4 (1), 131. Ingallinella, a M.; Sanguinetti, G.; Koottatep, T.; Montanger, A.; Strauss, M. The challenge of faecal sludge management in urban areas--strategies, regulations and treatment options. Water Sci. Technol. 2002, 46 (10), 285–294. Boot, N. L. D.; Scott, R. E. Faecal sludge in Accra, Ghana: problems of urban provision. Water Sci. Technol. 2009, 60 (3), 623–631. Oyoo, R.; Leemans, R.; Mol, A. P. J. The determination of an optimal waste management scenario for Kampala, Uganda. Waste Manag. Res. 2013, 31 (12), 1203–1216. Nelson, K. L.; Murray, A. Sanitation for Unserved Populations: Technologies, Implementation Challenges, and Opportunities. Annu. Rev. Environ. Resour. 2008, 33 (1), 119–151. Ashipala, N.; Armitage, N. P. Impediments to the adoption of alternative sewerage in South African urban informal settlements. Water Sci. Technol. 2011, 64 (9), 1781–1789. Kennedy-Walker, R.; Holderness, T.; Alderson, D.; Evans, B.; Barr, S. Network modelling for road-based faecal sludge management. Proc. Inst. Civ. Eng. Eng. 2015, 167 (ME3), 157–165. Bassan, M.; Mbéguéré, M.; Tchonda, T.; Zabsonre, F.; Strande, L. Integrated faecal sludge management scheme for the cities of Burkina Faso. J. Water, Sanit. Hyg. Dev. 2013, 3 (2), 216. Chowdry, S.; Kone, D. D. Business Analysis of Fecal Sludge Management: Emptying and Transportation Services in Africa and Asia. 2012, No. September, 116. Coffey, D.; Gupta, A.; Hathi, P.; Khurana, N.; Spears, D.; Srivastav, N.; Vyas, S. Revealed Preference for Open Defecation. Econ. Polit. Wkly. 2014, 49 (38), 43–55. Coffey, D.; Gupta, A.; Hathi, P. Culture and the health transition: Understanding sanitation behavior in rural north India; 2014. Tilley, E.; Strande, L.; Lüthi, C.; Mosler, H.-J.; Udert, K. M.; Gebauer, H.; Hering, J. G. Looking beyond Technology: An Integrated Approach to Water, Sanitation and Hygiene in Low Income Countries. Environ. Sci. Technol. 2014, 48, 9965–9970. Fobil, J.; May, J.; Kraemer, A. Assessing the relationship between socioeconomic conditions and urban environmental quality in Accra, Ghana. Int. J. Environ. Res. Public Health 2010, 7 (1), 125–145. Parkinson, J.; Boot, N. Assessing demand for faecal sludge management ( FSM ) services in Freetown. Waterlines 2016, 35 (4), 336–356. Berendes, D.; Kirby, A.; Clennon, J. A.; Raj, S.; Yakubu, H.; Leon, J.; Robb, K.; Kartikeyan, A.; Hemavathy, P.; Gunasekaran, A.; et al. The Influence of Household- and Community-Level Sanitation and Fecal Sludge Management on Urban Fecal Contamination in Households and Drains and Enteric Infection in Children. Am. J. Trop. Med. Hyg. Accepted. Kolsky, P. J.; Butler, D. Solids size distribution and transport capacity in an Indian drain.
ACS Paragon Plus Environment
19
Environmental Science & Technology
456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476
(41)
(42) (43)
(44)
(45)
(46)
Page 20 of 28
Urban Water 2000, 2 (2000), 357–362. Turley, R.; Saith, R.; Bhan, N.; Rehfuess, E.; Carter, B. Slum upgrading strategies involving physical environment and infrastructure interventions and their effects on health and socio-economic outcomes (Review); 2013. Unger, A.; Riley, L. W. Slum health: From understanding to action. PLoS Med. 2007, 4 (10), 1561–1566. Berendes, D.; Leon, J.; Kirby, A.; Clennon, J.; Raj, S.; Yakubu, H.; Robb, K.; Kartikeyan, A.; Hemavathy, P.; Gunasekaran, A.; et al. Risk factors for pediatric enteric infection in a low-income urban neighborhood in Vellore, India: Examining the contributions of the household environment, neighborhood geography, and exposure behaviors. In Water and Health Conference: Where Science Meets Policy; 2016. Acker, W.; Parkinson, J.; Mabote, M.; Campos, L. C. Assessing health risks associated with municipal sanitation systems in Maputo, Mozambique. Waterlines 2016, 35 (4), 397– 411. Baum, R.; Luh, J.; Bartram, J. Sanitation: A global estimate of sewerage connections without treatment and the resulting impact on MDG progress. Environ. Sci. Technol. 2013, 47 (4), 1994–2000. Zuerbruegg, C.; Tilley, E. A system perspective in sanitation – Human waste from cradle to grave and reincarnation. Desalination 2010, 251 (May 2008), 410–417.
477
ACS Paragon Plus Environment
20
Page 21 of 28
Environmental Science & Technology
Table 1: Sanitation coverage and location of drinking water source by country and WHO region among surveyed nations Sanitation coverage and type Sewered FSM needed No facility On-premises piped
All countries (n = 58) Africa (n = 33) Angola Benin Burkina Faso Burundi Cameroon Chad Comoros Dem. Rep. Congo (DRC) Rep. Congo Cote d’Ivoire Ethiopia Gabon The Gambia Ghana Guinea Kenya Lesotho Liberia Madagascar Malawi Mali Mozambique Namibia Niger Nigeria Rwanda Sao Tome and Principe Sierra Leone Tanzania Togo Uganda Zambia Zimbabwe LAC3 (n = 7) Bolivia Colombia Dominican Rep. Guyana
Location of drinking water connection Other onNot on-premises premises/neighbor Total pop.2 Mean %1 Total pop.2 Mean %1 Total pop.2 693,404,785 1.9 146,891,193 70.1 2,348,469,785
Mean %1 14.0
Total pop.2 316,555,344
Mean %1 62.8
Total pop.2 1,774,646,390
Mean %1 21.6
Total pop.2 1,073,001,372
Mean %1 26.3
5.4 7.6 1.3 0.6 1.1 0.8 0.9 5.3 0.2
30,861,856 1,528,842 143,235 114,192 119,586 202,626 102,381 42,351 173,509
65.4 13.2 43.5 50.1 95.9 92.0 28.1 92.4 85.0
577,391,250 2,660,805 4,673,442 9,779,179 10,642,929 22,413,865 3,327,184 733,944 69,136,238
27.5 40.7 54.2 49.0 3.0 7.0 71.0 0.8 14.7
225,737,951 8,208,601 5,823,062 9,567,314 336,784 1,716,622 8,415,066 6,440 11,965,843
17.9 12.7 19.9 13.1 5.1 14.7 5.6 37.9 15.2
96,256,978 2,560,256 2,142,270 2,556,771 564,626 3,585,025 659,492 301,257 12,362,962
0.7 0 0 0 1.8 0 0 0 0
8,640,317 0 0 0 203,615 0 0 0 0
81.4 87.3 80.1 86.9 93.1 85.3 94.3 62.0 84.8
742,524,581 17,612,076 8,599,188 16,954,326 10,329,652 20,769,262 11,172,449 492,167 68,951,625
1.6 6.4 0.6 33.2 2.6 7.8 3.0 10.0 1.4 1.0 0.2 3.5 1.5 0 37.3 0.6 5.5 1.3 5.8
78,910 1,523,470 595,967 577,528 51,282 2,106,401 368,094 4,672,579 28,179 43,968 40,586 649,314 256,438 0 908,277 110,094 10,158,331 165,596 11,391
89.6 60.1 56.4 63.5 95.2 75.2 77.4 81.6 71.4 53.5 43.3 84.2 87.3 58.3 16.0 26.6 65.0 94.0 32.3
4,347,436 14,256,340 57,709,987 1,103,764 1,913,845 20,245,354 9,363,303 38,164,707 1,395,101 2,299,195 10,570,207 15,627,166 15,251,150 15,122,858 389,366 4,949,480 120,960,291 12,206,930 63,850
8.7 33.2 38.3 2.3 2.1 16.9 19.5 8.0 27.1 45.2 56.5 12.2 11.0 41.7 46.3 72.8 29.4 3.9 61.4
421,091 7,892,666 39,230,191 40,217 42,219 4,544,237 2,354,183 3,753,824 529,666 1,942,180 13,798,349 2,267,951 1,924,261 10,807,292 1,127,743 13,566,790 54,741,717 507,909 121,321
25.4 31.5 11.0 63.7 41.5 9.7 22.2 24.2 25.6 1.1 2.8 14.2 8.9 10.8 50.9 7.2 2.8 9.5 30.6
1,231,022 7,471,807 11,273,281 1,108,172 834,865 2,616,601 2,685,567 11,330,076 499,662 46,044 693,069 2,644,986 1,555,712 2,806,116 1,241,232 1,337,438 5,175,068 1,229,950 60,370
0 0 0 0.4 0 0 0 0 0 0 0 0 0 6.3 0 0 0 0 0
0 0 0 6,247 0 0 0 0 0 0 0 0 0 1,641,587 0 0 0 0 0
74.6 68.4 88.9 35.7 58.4 90.3 77.7 75.8 74.4 98.8 97.2 85.8 91.1 82.8 49.0 92.8 97.0 90.5 69.4
3,619,567 16,246,299 91,061,315 620,575 1,172,910 24,291,661 9,402,358 35,460,682 1,453,408 4,250,152 23,737,256 15,925,335 15,911,396 21,482,447 1,192,663 17,301,162 180,531,398 11,753,375 137,171
0.2 0.7 0.1 0.6 10.2 26.8
14,249 348,081 4,120 244,695 1,581,279 3,896,307
77.8 86.6 50.3 93.4 73.5 46.9
4,684,981 45,471,705 3,900,354 35,794,731 11,407,105 6,824,457
21.4 12.3 48.8 5.7 16.2 26.2
1,286,522 6,474,557 3,786,204 2,199,710 2,519,829 3,817,593
3.6 10.8 5.7 6.2 18.1 28.8
218,404 5,658,961 438,616 2,368,910 2,812,463 4,185,926
0 12.6 0 0.5 0 0
0 6,606,672 0 182,196 0 0
96.2 76.6 94.3 93.3 81.7 71.2
5,790,009 40,217,093 7,311,512 3,574,177 12,671,430 10,361,035
31.3 75.0 72.9 4.2
46,342,876 35,415,596 7,731,733 30,981
55.1 20.1 23.7 94.7
44,666,150 9,508,821 2,509,509 697,212
10.0 4.8 3.4 1.0
11,189,454 2,267,916 363,569 7,451
48.5 78.7 83.9 10.6 32.4
78,346,621 8,636,131 39,621,592 1,128,415 238,352
0.5 0 0 0 0
768,541 0 0 0 0
50.9 20.9 16.1 89.4 67.6
40,482,594 2,293,483 7,599,264 9,478,229 497,389
ACS Paragon Plus Environment
21
Environmental Science & Technology
Page 22 of 28
Haiti Honduras Peru
1.0 34.4 0
108,934 3,055,625 0
73.6 55.9 62.7
7,715,094 4,971,207 19,264,308
25.1 9.4 16.5
2,632,616 834,991 5,082,912
8.6 48.6 76.4
906,134 4,317,778 23,498,159
1.7 0 1.9
174,493 0 594,048
89.6 51.4 21.6
9,391,107 4,574,265 6,648,856
E. Med. (n = 3) Jordan Pakistan Yemen
38.2 60.3 29.6 24.5
71,535,375 4,938,352 59,877,818 6,719,204
46.1 39.7 49.0 49.8
115,771,012 3,245,787 98,880,200 13,645,025
15.5