Expanding safe fecal sludge management in Kisumu, Kenya: an experimental comparison of latrine pit-emptying services

Most residents of Kisumu, Kenya, use latrines constructed over basic pits or attached to more durable concrete vaults and septic tanks. Only one-third of fecal sludge generated in the city, however, is safely collected and treated. Programs for improving fecal sludge management among poor households include the development of formal manual emptying organizations that are recognized by local authorities, employ safety procedures, and transport fecal sludge to a treatment site. In this study, we compared the financial structures of these organizations with those of vacuum trucks that primarily serve wealthier households. We also employed an incentives-based strategy to promote the expansion of safe pit-emptying services in a low-income area and compared the performance of three managing groups to coordinate these services: (1) The Association of Wastewater Managers (The Association); (2) a formal manual emptying organization; and (3) a community-based water supplier interested in coordinating emptying services. Vacuum trucks were more cost-effective than the formal manual emptying organization, and The Association was most efficient in servicing poor households. The Association also demonstrated the ability to service lowincome areas comprehensively by delegating a fraction of jobs (11%) to formal manual emptiers in locations not serviceable by VTOs, and overall showed the highest potential to achieve pro-poor service delivery at scale.


INTRODUCTION
and (2) we established an incentives-based latrine pitemptying program to compare the performance of three managing groups in coordinating the delivery of emptying services in a low-income area of Kisumu.

Landscape assessment
We began our comparisons of latrine pit-emptying options in Kisumu by establishing the landscape of existing emptying services: VTOs, formal manual emptying organizations (BlueStars, Vukasasa, Gasia Poa), and informal manual emptiers ( Figure 1). To verify business models, establish customer bases, and identify barriers for expansion within lowincome areas, we conducted 18 interviews and observations of pit-emptying service providers. Additionally, we reviewed nine policy documents and 25 reports on past sanitation programs and interviewed 17 government and nongovernmental stakeholders to understand the regulatory environment ( Figure 1). To understand efforts to improve sanitation in other Kenyan cities, we interviewed sanitation service providers in Nakuru (Nakuru Water and Sanitation Services Company), Malindi (Malindi Water and Sewerage Company), and Nairobi (Sanergy, a fecal sludge management organization with for-profit and non-profit operations).
Finally, to establish a forum for regularly engaging with local stakeholders, we formed a working committee in Kisumu that included the City and County Public Health Departments, KIWASCO, Great Lakes University Kisumu, and WSUP. The research team met five times with the working committee over the course of the study.

Cost of safe pit-emptying
We used the information collected during interviews with service providers to estimate the costs that they incur per emptying job. We considered both capital expenditures labor, truck maintenance, fuel, a monthly permit to access the treatment facility, and a quarterly membership fee to the Association for VTOs. To estimate costs per emptying job, we first calculated annual costs and then normalized by the approximate annual number of jobs: 2,160 for a VTO (or 6 jobs per day) and 60 for the group of manual emptiers (5 jobs per month), based on currently reported levels of activity.

Managing groups for pit-emptying
Our sanitation landscape assessment and working committee stakeholder consultations identified the need for exploring different management models for pit-emptying services. For our comparative study, we applied the following criteria to select groups that were either already providing safe pit-emptying services or interested in expanding into pit-emptying: (i) currently operating in the low-  (Table 1). Throughout our comparative study, these selected groups managed their delivery of safe emptying services: they were responsible for marketing services, identifying customers, setting prices, and coordinating pit-emptying jobs.
All three managing groups could delegate jobs to either VTOs or formal manual emptiers. In the case of the Wastewater Association, delegating a job to a VTO meant to assign it to one of its own members. Similarly, for Vukasasa, delegating a job to formal manual emptiers meant to assign it to its own members.
To standardize operating conditions for the three managing groups during our study, we selected three separate geographic zones in the Nyalenda area (out of 12 zones that we evaluated) according to the following specifications: (i) inclusion of 500-700 households; (ii) equidistant to the KIWASCO treatment site; (iii) demarcated by clear boundaries such as roads or rivers; (iv) near the offices of the managing group (did not apply to the Wastewater Association); and (v) approved by the managing groups.

Cash incentives
To encourage participation in our comparative study of pitemptying services, we provided cash incentives to the managing groups ( Figure 2). In addition to the payments that they negotiated with customers, we provided managing groups with a 3,000 KES (30 USD) cash incentive for each emptying job that they completed within their assigned zone during our study period. We selected this amount to address the estimated gap between market prices for VTO and formal manual pit-emptying services in Kisumu and the average willingness-to-pay (WTP) for pit-emptying among poor households, who largely rely on informal manual emptiers (who charge 10-30 USD per job according to our landscape assessment). We measured WTP in a parallel study (Peletz et al., forthcoming). Recognizing that the costs of formal manual emptying were higher than VTOs primarily due to transport, we provided an additional incentive payment of 2,000 KES (20 USD) per trip to the treatment site for pit-emptying jobs completed by formal manual emptiers to support the costs of transporting fecal sludge from the study zones to the KIWASCO treatment site. These incentives were necessary to promote the expansion of formal pit-emptying services into previously non-serviced areas. We implemented them for a period of 2 months, as defined by our available budget. This period was sufficient to measure differences in performance between the three managing groups.
Other than defining the zones and providing cash incentives as described above, we did not apply other constraints or guidelines on the three groups. We did not provide capacity building to any of the managing groups.
A fundamental element of the research design was giving the groups substantial flexibility to determine key elements of their business model, including choice of provider (VTO or manual), price charged to customer (reflecting the specifics of the job including condition and accessibility of pit), and the price paid to the service provider.

Data collection
We collected data from June to July 2019 to assess the fol-

Data analysis
We analyzed data using the spreadsheet software program

Costs of safe emptying by different service providers
We analyzed the capital and operating expenses of VTOs and formal manual emptying organizations in Kisumu prior to beginning our comparative study with the three managing groups (  (Table 3). These challenges in data management do not affect the cost analysis in Table 2, which describes expenditures prior to the comparative study.

Safe emptying jobs performed
We confirmed that The Wastewater Association coordi-  (Table 3). Because our landscape assessment revealed that formal service  (Table 3). Vukasasa delegated all jobs to its members and did not subcontract any jobs to VTOs. We also found that all groups serviced a variety of toilet types (Table 3).

Financial metrics of managing groups
The cash incentives that we provided motivated all three managing groups to reduce the prices of emptying services, and, therefore, served as subsidies for their customers (

Customer feedback
The Wastewater Association's customers reported the highest satisfaction levels: they gave an average rating of 4.3 (on a 5-point scale) and 78% reported that they would use the We excluded all records that were not validated by independent enumerators (e.g., households not found or no emptying done) from analysis: these included 1 record for The Wastewater Association, 19 for Vukasasa, and 26 for Nyalenda Water. b We estimated the volume of sludge removed by VTOs based on exhauster truck capacity. We estimated the volume of sludge removed via formal manual emptying by multiplying the number of barrels used (of either 60, 120, or 210 L capacity) with the number of trips required to transport the sludge to the treatment site. same service again at the same price (Table 5). When the Wastewater Association's customers were asked what they liked about the service, their most common response was price (56%); when asked what they did not like, only 9% responded that their pits were partially emptied and only 3% responded that the solid waste was not removed Numbers in parentheses represent losses.
Exchange rate is 1.00 USD ¼ 100 KES (6 June 2019, oanda.com). a For jobs completed by formal manual emptiers, we provided a 20 USD incentive per trip to the treatment site. The average incentive therefore is equal to the proportion of jobs completed by formal manual emptiers multiplied by the average number of trips to the treatment plant multiplied by 20 USD. We also employed a financial incentives-based strategy to promote the expansion of safe pit-emptying services in a low-income area and compared the performance of three managing groups to coordinate these services: (1) The Wastewater Association; (2) a formal manual emptying organization; and (3) a community-based water supplier seeking to expand into pit-emptying.
Our economic analysis showed that VTOs were about four times more cost-effective than formal manual emptying organizations ( Table 2). The main contributors to higher operating costs for formal manual emptying included truck rentals for transporting fecal sludge to the KIWASCO treatment site and labor expenses ( Table 2). The Wastewater Association was more efficient in coordinating emptying services in low-income areas than the formal manual emptying organization and the community-based water supplier, both in the numbers of pits emptied and in the numbers of trips required to transport fecal sludge from an emptied pit to the treatment site (Table 3). The Wastewater Association also received the highest customer satisfaction ratings (