Faecal sludge management - FSM sub-project

Rationale of the project

In large cities of Vietnam, approx. 25 - 60 % of urban residents rely on septic tanks for residential sanitation. A variable share of urban households do not avail of private toilets and, hence, depend on the use of public toilets, the majority of which are unsewered. In smaller cities, the majority of those at all availing of sanitary facilities employ pit (some of them with urine separation) or bucket latrines. The average share of on-site sanitation systems throughout the towns and cities in Vietnam is estimated at 70-90 %. A major problem is the fact that faecal sludges (FS) collected from these on-site sanitation installations are commonly disposed of untreated. In larger cities, haulage distances to outlying treatment or disposal sites are excessive and traffic congestion prevents efficient emptying and haulage of faecal sludges. The sludges are therefore dumped untreated at the shortest possible distance, be it on open grounds, into drainage ditches and water courses, or used untreated in agriculture or for fishpond fertilization. Growing urbanisation leads to increasing faecal sludge quantities to be disposed of and, hence, to increasing environmental pollution and health risks. Besides faecal sludges, cities are also faced with the collection and disposal of sludges originating from the dredging of surface drains and canals – sludges, which also carry considerable shares of faecal matter

originating from FS discharges and from the disposal of greywater and septic tank supernatants.

An increasing number of national and municipal authorities feel the need to improve the management of faecal sludges. CEETIA decided in 1998 to respond to this need by launching an applied research project on this subject in the framework of the ESTNV project.

Objectives of the FSM project

The challenges for improving FS management in Vietnam are manifold and encompass the need to develop and introduce appropriate FS treatment options; to develop equipment suitable for accessing pits in densely built-up settlements; to develop transfer schemes enabling the haulage of manually emptied FS to designated treatment sites; promotion and regulations for private entreprise development in the FS management sector, and to enable money flux schemes, which render pit emptying affordable to all households and create win-win situations for all stakeholders.

The FSM sub-project at CEETIA, under the leadership of Ass. Prof. Dr. Kim Thai, aims at finding solutions to some of these challenges. The main focus is set on the following objectives:

-      To develop suitable analytical methods at CEETIA to monitor FS generation, collection, treatment and use.

-      To assess the FS management practices in different city districts and towns, including identification of problems, needs, constraints and institutional set-up.

-      To develop suitable treatment solutions for FS, such as planted humification beds or co-composting with organic waste.

-      To develop technical guidelines and training manuals about FSM for policy makers and practicioners.

Research on treatment options

Two PhD theses are currently being conducted on low-cost treatment options for faecal sludge. The first PhD study investigates septage treatment in constructed wetlands; the second PhD study investigates the joint treatment of FS with organic solid waste.

In the co-composting process, FS is composted together with organic solid waste. Temperatures in the heaps should reach 55-60°C and inactivate the pathogens. The produced compost constitutes a very good soil conditioner.

Constructed wetlands consist of a gravel/sand/soil filter equipped with a drainage system and planted with emergent plants such as reeds, bulrushes or cattails. The sludge is loaded on the bed and dewatered by percolation in the filter and by evapotranspiration through the plants. The root system of the plants maintains the permeability of the sludge layer. Sludge has to be removed only once every few years. The long solids retention period favors mineralization and pathogen die-off and allows direct reuse of solids in agriculture.

Research on non-technical issues

CEETIA also looks at non-technical aspects of faecal sludge management. Several studies were and are currently being conducted in collaboration with national and international partners. The studies aim at highlighting problems of the current FS management practices and at developing suitable institutional and economic setups enabling a more sustainable management of faecal sludge in Vietnam.

The main studies are highlighted below:

-      Household and stakeholder survey on faecal sludge emptying practices

-      State of the art reports on faecal sludge management practices in Vietnamese cities

-      Identification of suitable sites in Hanoi for the implementation of faecal sludge treatment plants, in collaboration with MOC

-      Optimisation of faecal sludge collection to suit with technical infrastructure in Hanoi City

-      Analysis of money fluxes in faecal sludge management in Vietnam

Additional information & contact

FSM Sub-project manager: Assoc. Prof. Dr. Nguyen Thi Kim Thai

Email add: canhthai@vnn.vn

 Other link:

   1. Study on FSM in Northern Vietnam – Money Flux Analysis in Hai Phong City
   2. Application of UASB process to the biological degradation of reactive dyes using         sucrose as a co-substrate
   3. Money Flux Analysis (MoFA) in Fecal Sludge Management (FSM)
   4. Pathogen removal in faecal sludge treatment by constructed wetlands