Questa’s Humanitarian Water and Wastewater Work
Questa Engineering possesses a unique set of skills that are directly applicable to water supply and wastewater projects in other countries with great need to develop decentralized sanitation infrastructure. We are experts at developing water and wastewater projects with significant capacity for communities where centralized water infrastructure is unavailable. Typically, low-tech, modern solutions can provide vast improvements over existing infrastructure.
We apply low-tech techniques, which in some cases have been around for hundreds of years, to modern problems. We have developed innovative ways to reuse plastic in the waste stream to provide biofiltration and aerobic digestion. These materials typically are readily available and can have secondary benefits in providing jobs within communities.
Water Supply Sand Filters
This older technology is still applicable in the modern age. Simple sand filters can be constructed in a low-maintenance and effective manner. By using a series of filters to remove sediment and stimulant biofiltration, water supply quality can be improved significantly.
Wastewater Treatment and Recycling Systems
Questa has been designing and installing decentralized wastewater systems throughout California for over 20 years. These systems have typically been high-flow, decentralized systems that were adapted to the site soil conditions. Questa soon became aware that its design experience could be applied to developing appropriate wastewater technologies to emerging and developing nations.
The Missing Link
In many countries throughout the world, sanitation design is handled predominantly in one of two ways: 1) centralized wastewater treatment facility or 2) a basic latrine. There are few options for safe, adequate systems that are not connected to a central system, but have high loads that can quickly exceed the ability of latrines, even properly constructed ones. As the density of latrines increases, so does the threat to public health and potentially to water supply quality. There is clearly a need for wastewater treatment where either a large centralized system was not practical or latrines were an inadequate solution. This condition could easily apply to a boarding school, community center, or village scale situation. Decentralized wastewater treatment system design occupies a sorely underutilized sub-set of the wastewater engineering field. Few modern day universities teach the techniques that can be directly applicable to small-scale, community based, wastewater treatment design.
Questa has been developing ways to utilize waste stream plastic bottles and containers to enhance wastewater treatment through increased biologic digestion efficiency. For many years it has been known that gravel substrate increases surface area for anaerobic digestive capability. Questa has developed designs that use cut-up plastic water bottles to increase the efficiency of existing septic tanks and to provide excellent media for leachfields and other subsurface wastewater disposal facilities. These techniques have been field tested and show great promise, especially in warm climates.
These techniques provide a win-win situation: taking a problem waste product and reusing it to provide enhanced sanitation for a community. Collecting and preparing bottles can also provide local employment opportunities. Our techniques can reduce plastic waste, improve sanitation efficiency and provide labor and economic benefits for communities.
Human Needs Project:
Questa is currently working in Nairobi, Kenya, with the Human Needs Project. This project was the brainchild of Marin County residents who wanted to build a community center and the accompanying water and wastewater supply.
Questa has been involved in meeting the challenge of bringing clean water and sanitation to a very small and contained site.
The project is currently under construction and hoped to be operational in fall of 2013.
The wastewater system design objectives and constraints are:
- Onsite toilets and bathing for 1,500+ people per day
- Estimated wastewater flows: 40,000 liters/day (10,000 gpd)
- Maximize Wastewater Recycling:
- Toilet flushing – (40% of waste flow)
- Irrigation – Onsite and offsite in Kibera (distributed for sack gardens)
- Onsite Percolation (last resort, failsafe)
- Constrained Space:
- 4,000 sq. ft. total area
- Maximize setback/protection of deep bore onsite water well
- Integrated/shared with other facilities and activities center
- Underground and containerized, as much as possible
- Appropriate/sustainable practices; appropriate for developing countries;
- Long-term reliability
- Passive, low energy (gravity flow, media filtration, pumps & UV)
- Operator simplicity – trainable skills
- Construction with local materials, as much as possible (concrete block)
- Use of recycled materials, as much as possible (waste plastic)
Clean Water Supply Projects – Fiji:
Rotary Water Foundation (RWF) funded the Vurevure Sanitation project. Norm Hantzsche, Principal/Managing Engineer of Questa, designed the material, led the apprenticeship training and provided engineering guidance on the project.
Future Projects and Opportunities
Questa is actively looking to team with governments and NGOs to apply our small-scale wastewater expertise to developing nations that are struggling with growing populations, lack of infrastructure and need for decentralized wastewater treatment.
We are also interested in developing engineering mentoring and foreign student internships.