VIE PDA: Adapting Appropriate Sanitation Solutions to Peri-Urban Areas (A PDA After Care Support) Midterm Report

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Asian Development BankRegional Technical Assistance

RETA 6498: Knowledge and innovation support for ADB ‘s waterfinancing program – Pilot and Demonstration Activity for Vietnam:Adapting Appropriate Sanitation Solutions for Peri-Urban Areas in

Vietnam: A PDA after-care support

PDA – Midterm Report

Submitted by EAST VietnamProject manager: Frances Antoine

October 30 th , 2010

The views expressed in this paper are the views of the authors and do not necessarily reflect the views or policies ofthe Asian Development Bank (ADB), or its Board of Directors, or the governments they represent. ADB does notguarantee the accuracy of the data included in this paper and accepts no responsibility for any consequences of theiruse. Terminology used may not necessarily be consistent with ADB official terms.



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EAST Vietnam - Non-governmental Organization3B Quoc tu Giam – Dông Da - Hanoi – Vietnam

Tel/fax: (844) 37 32 60 69- Email: [email protected]

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1. Background

In April 2008, the NGO EAST Vietnam launched a Pilot and DemonstrationActivity (PDA) as part of ADB’s Regional Technical Assistance for Promoting EffectiveWater Management Policies and Practices (RETA 6498). This PDA was aimed at

Developing Appropriate Sanitation Solution for Peri-Urban Areas. It focused ondecentralized wastewater treatment models to be replicated in other projects with similarcontexts. It foresaw, among others, the implementation of a pilot treatment system ableto handle domestic wastewater issued from around 50 households. Based on DEWATStechnology, the system consists of a series of complementary treatment componentscombined with a separated network collecting black and grey water. The project islocated in Kieu Ky.

Cf. Appendix 1

In February 2009, the pilot treatment plant was completed and management,operation and maintenance was handed over to the community. EAST Vietnamproposed within the PDA a model for local management and its financing mechanisms.

However, these responsibilities are new for the local representatives in charge and mayrequire technical support. Moreover, the system management will need updates andimprovements to fit the local context and the technical requirements as well as possible.

To achieve sustainability of the system, EAST foresees an amelioration of theexisting system and the extension of the project, taking into consideration the lessonslearned from the first experience of the PDA. The partners will opt for a combinedsystem using existing infrastructures. Indeed, the separate piped system implementedwithin the PDA was not able to connect all households’ septic tanks because of theheterogeneity of construction and wasn’t very efficient.

The letter of Agreement (LOA) between ADB, EAST Vietnam and the executingagency (EA), was signed on June the 15 th, 2010. The project, scheduled for 6 months,aims at gathering information and data on the local situation and proposing appropriatesanitation solutions to get a sustainable sanitation system.

Objectives

The main objective of the PDA was to develop technical, management andfinancial systems for peri-urban areas, able to be replicated in other projects. Taking intoconsideration that the covering area will be soon extended through another type ofcollection system, this technical assistance aims at evaluating, improving and adapting if

necessary the model proposed in the PDA. It will refine the management, operation andmaintenance (O&M) system as well as the financial mechanisms already set up throughthe PDA, thus ensuring sustainability of the project. The lessons learned from this PDAwill permit us to select the most suitable system of wastewater collection to be applied inViet Nam’s peri-urban areas.



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Scope of work

The scope of work focuses on Monitoring and Evaluation (M&E) of the actualmanagement, O&M system, the financial mechanisms and the technical choices already

set up through the PDA. Therefore, it will include several field trips, surveys, analysesand meetings with the local representatives to support them in their responsibilities. Inaddition, the scope concentrates on the evaluation of the opportunity of combinedcollection system related to the technical choices made within the pilot treatment plantand its collection system

Activities description

Activities description Main outputs/outcomes

M&E of the management, O&M system andfinancial mechanisms Synthesis note including:

The state of separated system and pilottreatment plant and on the origin of observedproblems

Proposition of a financing mechanism tosupport the O&M system (extension)

Guide:Elaboration of a small document which wouldspecify the management, the O&M modalities andthe responsibilities of each actor (for the pilot zone

+ extension)

Diagnostics of the separated network andthe treatment system after one year and half ofuse (including topographic study of the area of theseparate system and analysis of the planttreatment’s effluent)

Assessment of actual financial managementand accounting issues

Assessment of actual quantitative andqualitative O&M requirements and realization foroperation of maintenance on the network and thepilot treatment system

Surveys on beneficiaries’ satisfactionSynthesis note identifying:

positive or negative effects such as bad smells,landscape valorisation, salubrity of the households,and based on the results of 3 surveys:

- after 6 months of utilization- after 1 ½ year of utilization- after works for extension

- Questionnaires regarding the satisfaction of theresidents after 6 months of utilization (November2009)

- Field trips to learn the expectations of thehouseholds about the actual state of the sewersystem (June 2010)

- Questionnaires regarding the satisfaction of theresidents after the extension phase

Evaluation of the potential of combinedcollection system. Synthesis note including:

The state of combined system and on theorigin of observed problems

Technical propositions and explanation of theone to implement (validation from the popularcommittee of Kieu Ky)

Analysis of the treatment plant system afterconnection to the combined system

Diagnostic of the combined system(including topographic study of the extension area)

Qualitative and quantitative survey on theflow of wastewater in the combined system

Comparative survey on technical solution forthe network of Kieu Ky (utilization, dimensions andlocation of wastewater’s pump, spillways, newsewers…)

Presentation of this survey to the PopularCommittee



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2. Progress of work

a. Overview of progress

Since the reception of the inception report, the key activities which were covered mainlyconcern the diagnostic of the separated network and the treatment system after one year and halfof use together with the diagnostics of the evaluation of the potential of the combinedcollection system. These activities allowed us to propose solutions to Kieu Ky PopularCommittee to connect the DEWATS to the combined collection system and to solveobserved problems. Realization works began September the 16 th and finished October the5 th

b. M&E of the management, O&M system and financial mechanisms

• Diagnostics of the separated network and the treatment plant after one year and halfof use:

The topographic study, including two field trips has been completed. It allows us to conclude that: The difference of slope between individual connections and separated network explains whymost of households couldn’t be connected (cf 2.c. )

One branch of the separated network is plugged due to slope problems (cf. appendix 1) Indeed slope problems cause stagnations of wastewater which progressively obstruct thenetwork. Thus certain householders had to break their manhole to connect their wastewaterback to the combined system

In the problematic street, manholes present a conception default which prevents inhabitantsto correctly scrape clean their manholes (cf. appendix 2).

Analysis of treatment plant’s effluents is in progress. Borda collected four samples during a field tripin September the 6 th and gave them to IESE for analysis.

• Assessment of actual financial management and accounting issues

Meeting with popular committee and residents of Kieu Ky confirmed that the low number ofbeneficiaries explained the blockade of the contribution system. Indeed, 20 contributions of 5000VND per month are not enough to pay for all the operations and maintenance of the system andthe network.

Furthermore, since EAST began to subsidize the initial operator, operation and maintenance on theplant treatment have been executed correctly. Inasmuch as the contribution system works,community management is possible.Unfortunately a few weeks ago, the operator, who is sixty years old, became sick and operationsand maintenance on the plant treatment are no longer executed. This shows that the communitymanagement of the system is very fragile.Discussions on the field with inhabitants of Kieu Ky, allowed us to see that DEWATS beneficiariesare ready to pay a professional service for operation and maintenance on the plant treatment andthe network associated.EAST identified a potential actor who could be able to realize this operation and maintenance- theEnvironnment and Sanitation Service from the district of Gia Lam (XLMT DT Gia Lam). This serviceis already in charge of the collect of Kieu Ky’s wastes and EAST used to work with this company.EAST began to discuss of this subject with the vice director of XLMDT Gia Lam. She seemed to bevery interested in this project.



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So over, meetings between XLMT DT Gia Lam, Kieu Ky’s Popular Committee and EAST areforeseen. This meeting will allow us to define precisely the role of each actor and to determinateterms of an eventual service agreement between Kieu Ky’s Popular committee and XLMT DT GiaLam.

• Assessment of actual quantitative and qualitative O&M requirements and realizationof the network and the pilot treatment system

Since the delivery of the treatment plant to Kieu Ky’s authorities, O&M on the network and the pilottreatment system has never been realized. According to Kieu Ky’s Popular committee thissituation was due to the blockade of contribution system.

So EAST began to subsidize DEWATS’s operator in July. Since then, operation and maintenanceon the plant treatment are executed correctly.

Kieu Ky’s inhabitants are in charge of operations and maintenance on the separated network. Theexperience showed that Kieu Ky’s inhabitants never tried to unblock the separated network whenthere were problems and they never cleaned individuals manholes. Indeed they preferred to solve

problems by breaking their manholes in order to be connected back to the combined system.On the other hand the experience showed that people of Kieu Ky used to realize operation andmaintenance on the combined system, otherwise their houses would have been flooded a lot oftimes.

EAST organized a cleaning day of the separated network with the village chief. During that day,EAST made some demonstrations with homemade tools. A lot of inhabitants saw thesedemonstrations. They learned how to unplug the separated system and how to clean theirmanholes. Now they can do these operations by themselves. The problem is the recurrence ofthese operations due to slope problems (cf. appendix 2).

c. Surveys on beneficiaries’ satisfaction .

The first survey was done on two samples of households in November 2009 the 12th:

• First sample: households connected to the DEWATS system and households supposed tobe connected to the DEWATSThis part of the survey shows that only 40% of households in the pilot area have beenconnected to the DEWATS . The main reason “not to be connected” is because the slope heightof the sceptic tank is too low .Most of the households connected are satisfied with the separated system and the DEWATS. Forhalf of them changes are varied: less bad smells, a cleaner street, less grey water and blackwater backup in latrines and sinks . For others nothing changed.The people dissatisfied belong to a problematic street where there is slope problems (confirmed by the topographic study). These problems of slope explain the persistence of badsmells and the proliferation of mosquitos.However not many people are satisfied by the operation and maintenance system. Due to a lowrate of connections, sanitation fees have been revaluated and households connected don’t want topay these fees. (cf appendix 3)

• Second sample: households belong the catchment area and not the pilot areaThe second part of the survey shows that a majority of households from this area would like to beconnected to the DEWATS. More than half of them have a sceptic tank. A big majority is ready topay sanitation fees around 5000VND per month. Black water and grey water are majoritydischarged in the combined network. (cf appendix 4)



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The second survey is based on field trips and meetings with inhabitants. It was done betweenJune and October 2010.These informal meetings with Kieu Ky’s inhabitants showed us that the separated network havemore and more problems due in largely to slopes problems. Kieu Ky’s inhabitants preferred toconnect back to the combined network instead of solving the problems.Therefore the system is not sustainable and corrective actions have to be taken. According to Kieu

Ky’s inhabitants, connecting DEWATS and combined network seems to be an excellent solution.

The first survey will consist of questions on beneficiary satisfaction after the renovation andextension works. This survey will concern every household connected to the DEWATS.

d.Evaluation of the potential of a combined collection system .

Based on the topographic study, the diagnostic of the combined system shows that 86% of itworks . The main problems of this network are concentrated in an alley of the village. (cf appendix5)

In the catchment basin, a great part of wastewater (blackwater 67% greywater 65%, cf appendix 4 )is discharged into the combined network.

The qualitative and quantitative survey on the flow of wastewater in the combined network showsthat the DEWATS is able to treat all of wastewater from Kieu Ky’s catchment basin. However thissurvey on the field shows that the outlet canal serves not only wastewater but rice field water also. (cf appendix 6)

Therefore the connection between the DEWATS and the combined network is conceivable but itrequires:- the construction of a new outlet canal in order to separate wastewater and rice field

water- the construction of a spillway to prevent rain water to enter in the DEWATS

- the resolution of observed problems.(cf appendix 7)

To solve the problems observed in the small street,2 solutions are conceivable but theyrequire significant works in the whole alley (cf appendix 7). After the presentation of these solutions, Kieu Ky’s popular committee decided to beginworks of connection between DEWATS and combined network and decided to wait thewater supply works to solve problems in the alley.

Now the connection between DEWATS and combined is in progress. It will probably befinished at the beginning of November.After works, analysis of treatment plants effluent will enable us to check if this new

connection disturbs the treatment system (cf appendix 8).



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Appendix 1Diagnostics of the separated network

The technical appendix shows longitudinal profiles of each branch of the separated

network. These longitudinal profiles based on the topographic survey enable us tounderstand which part of the network doesn’t work or is susceptible to be blockaded.

The map below gives an overview of the main problems of the separated network,identified due to longitudinal profiles and observations made on the field.

Slope problems affect a big part of the separated network (around 45%). Theseslope problems are due to a bad realization and conception map with too lowslopes (1‰).

Separated networkfonctional

Slope problems inthe separated

network

Punctual problems

1 : Slope problems forced some households to reconnectthemselves to the separated system by breaking theirmanholes2 : manholes conception and slope problems entrain black

water reversion in latrines and sinks3 : a lot of rain water infiltrations through manholes cause asaturation of DEWATS during storms

1

2

3

Separated network main problems map



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Appendix 2Cleaning manholes and separated network workshop

During the demonstration of manhole cleaning, it appeared that some manholes wereimpossible to clean. Indeed, a lot of manholes are crossing the combined network (PVCpipe) which prevents the access to manholes bottom.

Kieu ky’s inhabitants watching the demonstration.

The workshop on cleaning manholes and separatednetwork showed Kieu Ky’s inhabitants how to unblock andhow to clean the separated network very simply.

The problem is the recurrence of these plugs due inmajority to slope problems.



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Appendix 3: Synthesis of the “survey on beneficiaries’ satisfaction»

0. General characteristic of the sample

Answers rate = 100 %

Definition: pilot area’s households (households connected to the DEWATS system andhouseholds supposed to be connected to the DEWATS)

Number of households interviewed: 50 (100% of households in the concerned zone)

1. Connections to a sanitation network in the pilot area

2. Reasons for not being connected

40 %

60 %50 %

10 %

Connected to the separated network

Not connected to the se arated network

Connected to the combined

network

too law

dont



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Only households connected to the separate system answered the following questions:

3. Are you satisfied with the separated system connected to the DEWATS?

4. Reasons for dissatisfaction

are



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5. How has the connection of your household to the new wastewatertreatment system changed your everyday life?

6.Are you satisfied with the community-based management of the project ?(fees revaluated to 12500VND)

Sanitations fees are toexpensive



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Appendix 4: Potential of new connections in the catchment area

0. General characteristic of the sample

Answers rate = 90 %

Definition: households from the catchment basin and not from the pilot area

Number of household interviewed: 47

1. Willingness to be connected 2. Sanitary infrastructures

3.Places where black water is discharged

67%

4%7%

23%

Common sewers Crop fields Rivers Cesspit



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4.Places where grey water is discharged

3% 3%

75%

9%5%

1% 4%

Houseyard

Roads Commonsewers

irrigationcanals

Lakes,ponds

Crop fields Cesspit

5.Willingness to pay



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Appendix 5Diagnostics of the combined network

The technical appendix shows longitudinal profiles of each branch of the combinednetwork. These longitudinal profiles based on the topographic survey enable us to

understand which part of the network doesn’t work or is susceptible to be blockaded.

The map below gives an overview of the main problems of the combined network,identified thanks to longitudinal profiles and observations made on the field.

Most of the combined network parts are functional (86%).Main problems are concentrated in an alley of the village. They arise from negative slopesand from the fact the sewer is not covered which entrain the presence of a big quantity ofwaste in the sewer.To solve these problems, this sewer will have to be rebuilt andcovered.

Combinednetwork

functionalSlope

problems inthe combined

networkPunctualproblems

12

3

4

1 : Construction work is plugging the combined networkwhich is not covered. On each side of the alley, there aretwo uncovered ditches and one is plugged.2 : Combined network is plugged there3 : People living there have overflow problems due to thelow height of their house in comparison to the combinednetwork height4 : in this alley, there is a big overflow problem due toslope problems in the combined network. Wastewater is

stagnating and there are a lot of flies, mosquitos and badsmells.Combined network main problems map



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Appendix 6Flow survey in the catchment basin of Kieu Ky

A-Qualitative survey

This survey is based on the inhabitants number of the catchment basin and on theaverage consumption of a Vietnamese from peri urban area: 175L/day.

Table of consumption of water Volume (in litres/per day)Basis domestic consumption 25Flush 9 x 5 = 45Shower 70 x 1,5 = 105Total 175

According to the topographic study, 4 households circled in red are discharging theirwastewater towards the river at different height which not enabled the connection toseparated or combined system. Therefore, these households are not considered in theflow calculation.

Consumption (m 3/day)Inhabitants number in the pilot area 100 18Inhabitants number in the extension area 140 24,1Inhabitants number in the catchment bassin 383 42,2

DEWATS

Household from the extension area

Household from the pilot area

Households which can’t beconnected to the DEWATS



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B-Quantitative survey

Kieu Ky’s wastewater (of which one part passes through theDEWATS) is evacuated into an outlet canal leading to Cau

Bay river.This canal is a part of the combined network. Moreover, a lotof observations on the field allowed us to down on him that theoutlet canal serves not only for wastewater but also for rice fieldwater.

Therefore this survey has been done on this canal in dryweather (dry weather for at least 6 days before the survey).

Survey’s principle:We timed the padding time of a 120L container positioned inthe canal. Measures were done every 30 min over one day

(24h).

Outlet canal of Kieu ky’swastewater

Flow is calculated as followed:

D(l/s) =

In order to put all of wastewater in to the container, we built a dam 50 cm high in thecanal.We put a PVC pipe to conduct wastewater in the container.

Argile dam One measure in progress Emptying the containerafter a measure

V : container’s volume = 120(l)t : time timed



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Results :

Here is the flow’s evolution observed in the outlet canal of Kieu Ky’s wastewater over aday : (Measure’s step = 30min) :

Kieu Ky’s catchment basin average flow: 23,5m3/day

Variations observed are coherent because they show a fall of the flow during siesta hours(13h30 – 16h00) and during the night (0h – 6h00).Peak flow took place in the morning (between 6h00 and 10h00), at midday (between11h30and 14h30) and in the evening (16h30-21h), moments when inhabitants werecooking and showering.

DEWATS capacities are sufficient to treat all of catchment basin wastewater.Indeed the DEWATS has a treatment capacity almost twice as large aswastewater flow observed. Therefore the security margin is really wide.

Differences between qualitative and quantitative survey arise from the factthat people in Kieu Ky are not connected to the drinking water network. As aresult they use less water than Vietnamese average for peri-urban area.

As rice field water passes through the outlet canal, a new one has to be builtto drive only wastewater to the DEWATS.



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Appendix 7Proposed solutions

A-Connection of the combined network and DEWATS:

According to the last conclusion, the construction of a new outlet canal is necessary toconnect DEWATS to the combined network. This new outlet canal will allow theseparation of rice field water from wastewater and also to discharge the existing canalwho is saturated during rainy weather.Moreover this new canal will collect wastewater from combined network and fromfunctional parts of separated network ( cf drawing 1)

.

The connection of DEWATS and combined network also requires the construction of aspillway to prevent rain water from entering in the DEWATS. A grill will have also to beinstalled to avoid solid waste entering in the DEWATS. (cf drawing 2)

The DEWATS

The existing outletcanal

The new outletcanal

Wastewater fromthe extension areaarrivalWastewater from

the pilot areaarrival

The rice field

Drawing 1 : The new outlet canal

The DEWATS

Rice fieldwater

Wastewaterfrom

catchmentbassin

The grille

The

spilway

Pipe which leadsto DEWATS entry

Drawing 2 : The grill + spillway



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The two canals will be recovered from concrete pavements to avoid solid waste enteringthe combined network and also to avoid bad smells (cf. Drawing 3).

Drawing 3 : overview of the new outlet canal with his cover

More details in the technical appendix.

B-Resolution of the alley’s problems

According to last conclusions (cf. appendix 5) , the alley’s combined network has to berebuilt.Different solutions are conceivable. All of them use gravity to function. The use of a pumpto lead wastewater to the DEWATS is inconceivable for several reasons:

• This system needs energy to function• This system needs a lot of operations and maintenance•

In the case of a breakdown of the pump, the DEWATS wouldn’t be supplied

a/ Solution 1

We will rebuild a new combined system in PVC pipes, Ø250mm. Wastewater willconverge due to the gravitational pull towards the combined sewer of the main street. Onemanhole will be built for each individual connection.These manholes will permit rainwaterto enter the combined network.

Longitudinal profiles ( cf. technical appendix) show that important earthworks will have tobe realized. Indeed the street’s level will have to be elevated to well covered PVC pipes.

This new sewer will be built in place of the old one (cf next map).



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b/ Solution 2

We will rebuild a new combined network covered in concrete ( cf. technical appendix) . Onemanhole will be built for each individual connection. A new pipe in PVC, Ø300mm, will bebuilt to lead alley wastewater and rainwater directly to the DEWATS ( cf next map).The concrete part of this new network will replace the existing combined network. ThePVC pipe will be buried and will pass through two inhabitants’ gardens ( cf next map). Anaccessible manhole will be build in the middle of this pipe for maintenance and cleaning.

Existing combinednetwork

Rebuild works oncombined network

Connection point



PVC pipe

Connection point

Localisation of works




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c/ Solution 3

We will rebuild a new combined network in PVC, Ø 250mm ( cf. technical appendix) . Onemanhole will be built for each individual connection. These manholes will also permitrainwater to enter in the combined network.

Longitudinal profiles ( cf. technical appendix) show that important earthworks will have tobe realized. Indeed street’s level will have to be elevated to well covered PVC pipes .Thisnew sewer will be built in place of the old one (cf next map).Then wastewater andrainwater will be lead toward the DEWATS through a PVC pipe ( cf next map). Manholeswill be built at every direction change of this pipe for maintenance and cleaning.

d/ Solutions comparaison



PVC pipe

Connection point




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Solutions Advantages Disadvanta

1

No change in the wastewater waycompared with the old combinednetwork

• This new combine

very low slope, so• Earthworks are bigwill have to be ele

• The cost of this so

2

• The new combined network slope isaround 1%. As a result wastewaterflow is guaranteed

• Earthworks in the alley are not big• Combined network in concrete is

easy to clean

• A PVC pipe has toterrains. This solutagreement

• Earthworks have tgardens

3 /

• This new combinevery low slope, so

• Earthworks are bigwill have to be ele

• The pipe’s length ihave to be build abfragile

• The cost of this so

In terms of sanitation, the second solution is the most appropriate but it needs the inhabitants’ agreement whichThe first solution is conceivable even if the slope of the new sewer isn’t high. However this solution meanswhole alley.



Appendix 8Progress of connection works between DEWATS and combined

network

Overview of the new outlet canal’s works

The spillway + the grill

Documents

VIE PDA: Adapting Appropriate Sanitation Solutions to Peri-Urban Areas (A PDA After Care Support) Midterm Report