How to Select Appropriate Emptying and Transport Technologies?

Non-sewered sanitation systems must be emptied properly to prevent the spread of disease and protect the environment. There are many emptying technologies and ways to transport faecal sludge but not all are appropriate for every situation. Selecting appropriate emptying and transport technologies is therefore a critical element of effective sanitation service chains and faecal sludge management.   

Relevance/Importance

Appropriate pit emptying and transportation options are important because sub-standard emptying can pose health risks to workers and the surrounding community and damage the environment. A general overview of the sanitation technology selection process and relevant criteria is provided in Technology Identification and Selection and How To Select Appropriate Technologies along the Sanitation Value Chain. Here the focus is on different types of emptying and transport technologies. 

Overview

A range of factors should be considered when selecting appropriate emptying and transport technologies. These include: 

• The accessibility of the latrines (e.g. is there vehicular access; what is the road quality and width?) 
• The quality and Quantity of Sludge, especially the sludge thickness  
• The presence of solid waste in the sludge 
• Transportation to the treatment/disposal site 
• Cost 
• Local regulations  

In the absence of sewers, common conveyance options include Manual Emptying and Transport, or semi- or fully – Motorised Emptying and Transport. 

Manual emptying involves the removal of waste by hand using shovels, buckets and other tools. This method is often used for small pits or where access to larger equipment is limited. However, it can be labour-intensive and pose health risks to workers. The emptied sludge can be buried on-site if space is available and there is no risk of groundwater pollution. A tree can be planted on top of the buried sludge (see Arborloo) to take advantage of the nutrients, add an extra protective barrier and reduce liquid percolation to deeper soil layers. Alternatively, the sludge is transported in barrels which should have a lid to avoid health risks.  

Manually operated emptying technologies such as the Gulper or the Sludge Digger have advantages over standard manual methods such as increased speed, reduced physical strain, improved hygiene, reduced odour and cost-effectiveness. However, it is important to ensure that workers are properly trained to use the technology and that the sludge is sufficiently homogeneous and liquid to be pumped smoothly.   

Motorised emptying and transport involve the use of machines, such as Pneumatic or Vacuum Pumps, to empty the sludge and barrels and uses specialised trucks equipped with a vacuum pump to remove the waste. This method is suitable for both small and large pits and can be faster and more efficient than manual or semi-mechanised emptying. However, it may not be cost-effective in areas with limited access or where the volume of waste is low. Small-scaled motorised alternatives to trucks exist such as Vacutugs for areas with limited access or where the terrain is difficult. 

For all these processes, protecting the Health and Safety of Operators and Workers is essential. This includes the use of Personal Protective Equipment (PPE) such as masks, gloves and boots as well as a place to wash equipment safely after each working day. 

In rarer cases when a functioning sewerage system is available (e.g. a Simplified Sewer or a Gravity Sewer), faecal sludge can be transported through the sewerage network and, ideally disposed of in the wastewater treatment plant, if one exists. However, the sewerage system may become overwhelmed if a large volume of faecal sludge is generated or if the system is damaged or blocked. 

There are many resources available to guide the selection of emptying technology. A Practical Guide to Available Pit-Emptying Technologies (Gursky et al. 2022) is a good start as it provides an overview of the available technologies and their application. The Guide provides a chart to rate the performance of available emptying systems according to the factors mentioned above (e.g. pit access or sludge thickness). This enables the comparison of the different technologies and the selection of the most suitable option based on the local context and available resources. Case studies can be found at the end of the Guide. Additionally, the Compendium of Sanitation Technologies in Emergencies provides several factsheets on different emptying and transport technologies. 

Whether an emptying service provider is hired or whether some or part of the work is done internally, it is essential to meet minimum requirements. The e-learning tool Transport and Emptying Services (CAWST 2022) helps ensure that the services provided meet or exceed the minimum requirements. 

Process & Good Practice

• Identify all the available local emptying and transportation options 
• Understand the characteristics of the sludge (e.g. its thickness, the presence of solid waste) 
• Follow all safety guidelines and procedures to protect the Health and Safety of Operators and Workers, including the use of PPE by emptiers, such as masks, gloves and boots, to prevent direct contact with faecal sludge 
• Ensure that the faecal sludge is treated and disposed of in an environmentally safe manner 
• Ensure the availability of a sufficient number and type of vehicles/equipment to meet the demand 
• Provide a designated washing facility for workers, vehicles and equipment 
• Work with local communities and authorities to ensure that the process is properly planned and executed and Standards along the Sanitation Service Chain are respected