Chapter 3. Engineering for Dignity: Water, Sanitation, and Hygiene (WASH) Field Exercise

Introduction

Access to clean drinking water, safe management of human waste and sanitation, and basic hygiene practices is not only essential for public health but also foundational to human dignity. In the wake of disasters, conflicts, or displacement, these basic services are often disrupted or absent entirely. Humanitarian engineers play a critical role in restoring and reimagining Water, Sanitation, and Hygiene (WASH) systems, working alongside affected communities to design practical, culturally appropriate, and sustainable solutions. This chapter introduces the concepts and calculations that underpin WASH practice in humanitarian contexts. Through case studies, you will explore not only technical aspects such as water quality testing and emergency response, but also the ethical dimensions of working in diverse, often vulnerable communities. Emphasising empathy, local knowledge, and rapid, context-sensitive problem-solving, this chapter invites us to approach WASH design not simply as an engineering task, but as a values-driven act of partnership and care.

In humanitarian engineering, the design and delivery of Water, Sanitation, and Hygiene (WASH) systems represent some of the most urgent and visible challenges in crisis settings, particularly where infrastructure has been disrupted or was never established. This chapter is structured into three sections: the first explores water supply planning and calculations related to quantity, the second focuses on water quality and treatment methods, and the third examines culturally relevant approaches to sanitation system design. In terms of Sanitation and Hygiene, multiple compendia of Sanitation Systems and Technologies address specific locations and geographies. It is essential to note that we will only briefly present the foundations of water and highlight relevant references for humanitarian intervention.

Water Systems  

Water Quantity calculations

The minimum standards in humanitarian response established by the Sphere Project are 7.5 to 15 litres/person/day (l/p/d) of water. Still, it is better to aim for 15 l/p/d at least for total basic water needs, including drinking, cooking, and basic hygiene practices. For survival needs (drinking and food), the basic needs are 2.5 to 3 l/p/d. In humanitarian contexts, understanding daily water requirements goes beyond simple survival calculations. When basic hygiene practices such as handwashing, bathing, and food preparation are included, the recommended daily water requirement increases significantly to an average of 20 litres per person per day [1].

In addition, cultural and social factors must be considered when planning water supply systems. Practices related to religious rituals, menstrual hygiene, and household caregiving responsibilities often require additional water. These needs vary by context but are essential to ensuring that water access supports dignity, inclusion, and local customs, not just the mere physiological requirement or biological need.

Water sources:

Harvesting water: a rain-dependent technique

Rainwater harvesting is a practical and sustainable method for collecting and storing rainwater, particularly valuable in areas where access to clean water is limited or unreliable. Common approaches include rooftop and courtyard harvesting, where rainfall is directed from surfaces into storage tanks or underground reservoirs. Effective water harvesting systems require thoughtful design, including appropriate catchment areas, gutters, and storage units.

To keep harvested water safe for use, ongoing care through treatment and maintenance is crucial. This can include simple filtration methods, systems that divert the initial runoff (first-flush), and routine cleaning of collection and storage components. Local communities should be able to assess whether their collection system is feasible and whether climate conditions and rainfall will allow them to collect enough water for their supply.

When designing water supply systems in low-resource or emergency contexts, it's important to estimate the amount of water that can be harvested from rainfall. A widely used formula for this is:

Q=P×A×Cr

Where:

• Q = Discharge or volume of water collected (measured in cubic metres, m³)
• P = Precipitation or the depth of rainfall over a given period (measured in metres, m)
• A = Catchment area or the surface from which water is collected, such as a rooftop or tank (measured in square metres, m²)
• Cr = Runoff coefficient, a dimensionless number that represents how much of the rainfall actually runs off the surface and is captured (ranges from 0 to 1).

Store sizing and water demand:

When locally designed and co-managed, rainwater harvesting systems can provide a reliable, community-controlled water source that supports both daily needs and resilience during times of crisis. To estimate the amount of water storage required based on dry season demand, the following formula can be used:

V = W × T

Where:

• V is the required storage volume (in litres or cubic metres)
• W is the average daily water demand
• T is the number of days the storage needs to supply water (e.g., the length of the dry season)

Peak demand:

Note: This would apply in the context of a community under regular conditions rather than in an emergency response.

Peak demand refers to the highest water use rate during a short period, often when many users simultaneously consume water [3]. To ensure a water supply system can meet this maximum demand, storage tanks must be adequately sized. This involves calculating future population growth, average and maximum daily water use, and applying a peaking factor to estimate peak flow rates [3]. To size a storage tank that meets peak water demand, first estimate the design population using the current population, growth rate, and project life.

Projected population at the end of the design period (linear growth):

$$P_N=P_0\times (1+\frac{r\times N}{100})$$

where,

$P_0$

​ = Current population

$r$

= Annual population growth rate

$N$

= Design period (years)

Average daily demand:

$$V_{avg}=P_N\times wR+V_{infrastructure}$$

Where:

$wR$

= average daily water requirement per person (L/p/d)

$wR$ $V_{infrastructure}$

= additional demand for schools, clinics, or other facilities

Maximum daily demand:

$$V_{max}=V_{avg}\times SF$$

Where:

$SF$

= safety factor (to account for peak demand)

 

Water Quality tests

Ensuring safe and clean drinking water is one of the most urgent priorities in humanitarian engineering. Contaminated water can lead to widespread disease, especially in vulnerable communities and emergency settings [4,5]. In practice, however, many humanitarian and development programmes aim to achieve a basic water supply, as defined by the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene (JMP)[6], rather than the higher standard of safely managed drinking water. The JMP service ladders distinguish between levels of service based on access, availability, and quality, and note that meeting basic access does not necessarily guarantee compliance with full water quality standards. Safely managed water requires that drinking water be free from harmful microbes and chemicals at the point of use, be available when needed, and be accessible on premises. Engineers assess water quality through biological and microbiological tests (to detect pathogens), chemical tests (to identify substances such as nitrates or heavy metals), and physical tests (including turbidity, colour, and temperature) [4,5]. While international water quality standards provide important benchmarks, strict application across all humanitarian contexts may result in costly, overly complex systems that are difficult to sustain. To balance safety with practicality, the World Health Organisation recommends Water Safety Plans (WSPs), a flexible, risk-based approach that identifies and manages hazards from the water source to the point of use [4]. This section, therefore, focuses on practical strategies for testing and improving water quality that support basic water services while progressively moving towards safely managed water, using both community-scale and household-level solutions.

Water quality is assessed through several categories of testing:

1. Physical Tests

   • Look at clarity (turbidity), colour, and temperature.

   • Ensure the water is visually acceptable and suitable for use.

2. Chemical Tests

   • Measure substances like nitrates, heavy metals (e.g., lead, arsenic), and pH levels.

   • Important for long-term health and for protecting infrastructure.

3. Biological and Microbiological Tests

   • Detect organisms such as E. coli, which indicate contamination from human or animal waste.

   • These are crucial for preventing diseases such as cholera and diarrhoea.

Note: Global guidelines set water-quality thresholds; applying them rigidly in low-resource or emergency settings can be challenging and lead to over-engineered, expensive solutions. Instead, a context-specific approach is often more appropriate, following minimum health and safety standards.

Improving water quality in low-resource or humanitarian contexts requires a practical and flexible approach. The World Health Organisation recommends Water Safety Plans (WSPs) as a comprehensive method to identify and manage risks throughout the entire water supply system from source to consumer [7]. These plans prioritise prevention over treatment, adapting to both basic and complex systems, and support gradual improvements rather than relying on rigid standards. Key strategies to enhance water quality include: boiling the water (for 2 min minimum) if there is a reliable fuel source (e.g., litres per person gas or biomass), filtration and chlorination at the source, as well as solar disinfection (SODIS), household filters, and chlorine use at the point of use. Coagulation/flocculation followed by disinfection can also be effective in removing contaminants. Safe water storage is critical because it allows solids to settle and reduces the risk of recontamination. To ensure water safety, simple testing methods can be used to monitor chlorine levels and adjust dosages accordingly, making sure treatment is both practical and safe for human consumption [6].

Chlorination

Chlorination is a standard method employed to disinfect drinking water under routine and emergency conditions [7]. Introducing chlorine or its derivatives into water can eliminate dangerous microorganisms, such as bacteria and viruses, rendering the water safe to drink [8]. The success of this treatment hinges on the chlorine concentration and the duration of contact with the water. Greater amounts require shorter exposure times [8]. However, both factors must be carefully managed to maintain efficacy while avoiding undesirable tastes or smells. Following treatment, a small amount of chlorine at an acceptable concentration (e.g., 0.5 mg/L) remains in the water to help protect it from contamination during storage and distribution [8].

When chlorine is added to water, some of it is used up reacting with substances already in the water. This is called the chlorine demand. At first, chlorine reacts with metals and other chemicals, becoming inactive. Then, it reacts with ammonia to form chloramines. If you keep adding chlorine, the chloramines break down. Eventually, you reach a point where there’s enough chlorine left to kill germs. This is called the breakpoint. After that, extra chlorine stays in the water as free chlorine, keeping it safe.

Coagulation / Flocculation 

Coagulation is the process in which chemicals (coagulants) are added to water to destabilise colloidal and fine particles. These particles are typically microscopic, carry electric charges (usually negative), and remain suspended in water, creating turbidity or colour [9]. Flocculation follows coagulation. It involves gently mixing the water to promote particle collision and aggregation, allowing the destabilised particles to form larger particles called flocs, which can be removed by sedimentation or filtration [10]. In water treatment, the pH is crucial. pH stands for "potential of hydrogen" and reflects the concentration of hydrogen ions (H⁺) in a solution. pH is a measure of how acidic or basic (alkaline) a solution is. It is expressed on a scale from 0 to 14. pH plays a critical role in the coagulation process because it controls the chemical form (speciation) and charge of coagulants like aluminium and iron salts. An optimal pH (5.5 and 7.5) must be maintained to ensure effective floc formation. Therefore, if the water pH lacks sufficient natural buffering (i.e., low alkalinity), the pH can drop too low, preventing hydrolysis reactions and reducing the effectiveness of coagulation.

Sanitation and Hygiene  

Sanitation and hygiene are fundamental to public health because they prevent the spread of infectious diseases by reducing exposure to harmful pathogens. Proper sanitation systems safely manage human waste, while good hygiene practices such as handwashing with soap break the transmission cycle of illnesses like diarrhoea, cholera, and typhoid. Improving sanitation and hygiene not only protects individual health but also contributes to healthier communities, reducing the burden on healthcare systems and supporting overall well-being.

Access to safe, appropriate sanitation remains a critical challenge in many low-income and crisis-affected settings. Humanitarian engineers play a key role in addressing this challenge by designing systems that are not only technically sound but also socially acceptable, affordable, and environmentally safe. This section introduces the fundamental principles and practical applications of sanitation technologies for rural and high-density urban areas, with a focus on everyday contexts in developing communities and on the ethical implications of co-designing sanitation systems.

As mentioned in the introduction, multiple compendia have been created around Sanitation and Hygiene. However, in this text, we only cover some content to illustrate its use in humanitarian engineering settings. More can be explored in the Compendium of Sanitation Systems and Technologies, by the International Water Association (IWA).

Water- and excreta-related diseases

Poor water, sanitation, and hygiene (WASH) conditions cause a significant global health burden, responsible for approximately 57 million disability-adjusted life years (DALYs) lost annually in low- and middle-income countries, compared to under 300,000 DALYs in high-income countries [11]. DALYs measure the years of healthy life lost due to illness or premature death, helping quantify the impact of water- and excreta-related diseases. These illnesses are transmitted primarily through faeco-oral pathways involving contaminated water, inadequate sanitation, and poor hygiene, with transmission routes including fluids (i.e., water), fields (i.e., soil), flies, fingers, and food (see F-diagram in Figure 1). Understanding these environmental transmission pathways enables engineers to design effective interventions to prevent diseases such as cholera, hepatitis, and soil-transmitted helminth infections.

Figure 1: F-diagram

Humanitarian engineering solutions must consider both waterborne and excreta-related diseases, as well as vector-borne diseases transmitted by insects and rodents, which are linked to poor sanitation. Control strategies include improving water quality and quantity, sanitation infrastructure, hygiene education, and vector control. For example, soil-transmitted helminths like roundworm and hookworm persist in contaminated environments and require effective excreta treatment and hygiene promotion to break transmission. Additionally, some water-related diseases have carcinogenic effects, such as bladder cancer from schistosomiasis. Through this integrated understanding of disease transmission and environmental factors, engineers can help reduce the global health burden by implementing sanitation and water interventions that address both the technical and social dimensions of health.

Designing Sanitation Systems

Selecting appropriate sanitation technologies requires more than technical fit; it demands careful consideration of local environmental conditions, such as groundwater vulnerability and population density, as well as cultural practices, such as anal cleansing methods. Technologies ranging from simple Arborloo latrines to advanced biogas toilets and simplified sewerage systems each have strengths and limitations that must be weighed in context. This implies not only considering what the climate conditions or weather dynamics over the year (either seasons or tropical rain/dry climate cycles), the availability of water resources, and even the soil characteristics, and the distribution of the housing conditions and community facilities, but also the cultural and social norms of the communities, as seen early in Chapter 2.

Therefore, sustainable sanitation is an approach that can be owned and maintained independently by communities beyond the initial design intervention, with meaningful community participation. Engaging residents and leaders through approaches such as Community-Led Total Sanitation [It is recommended to check The Community-Led Total Sanitation Approach - Sanitation Learning Hub] and community-managed sanitation blocks ensures that systems are co-designed, culturally acceptable, and maintained over time by community members who pay for their upkeep. This shared responsibility model counters dependency by involving communities not only in installation but also in financing, management, and maintenance, fostering ownership and resilience. Therefore, humanitarian engineering solutions must integrate technical design with social processes to achieve lasting health and environmental benefits in developing communities.

Note on video Reinventing Toilets: The toilet shown in this video does not necessary follow an Appropriate Technology approach (See Chapter 2). Its design is likely too expensive, complex, and water-intensive for poor rural or peri-urban settings. Local materials, low-cost options, and simple maintenance are essential for toilets to be practical and sustainable in these communities.

Arborloo: This is a basic type of composting toilet in which a shallow pit is dug, used for a short period, then covered with soil and planted with a tree, often a fruit tree. Over time, the waste breaks down and helps fertilise the plant. It’s a low-cost, eco-friendly option for rural areas.

Single-pit ventilated improved pit (VIP) latrines: These latrines use a bottomless pit to collect waste and a vent pipe to reduce odours and keep flies away. It doesn’t require water and is designed to be simple to use and maintain. The vent and dark interior help trap and kill flies, improving hygiene.

Single-pit pour-flush (PF) toilets: These latrines use a small amount of water to flush waste into a pit. They offer more comfort and cleanliness than a regular toilet, but require a reliable water source. The pit also allows wastewater to soak into the surrounding soil slowly.

Exercise 5: Design a Single-Pit Pour-Flush (PF) Latrine - Honduras

You are a humanitarian engineer working in a rural community in El Rosario-Comayagua, Honduras. The community has about 600 families, many of whom rely on subsistence farming and seasonal labour in coffee plantations. After recent floods damaged shallow wells and pit latrines, families are rebuilding with support from NGOs. A family of 6 people will be using a single-pit pour-flush toilet, and you have been tasked with designing the pit to last 10 years. The site has sandy loam soil; the water supply is provided via rainwater harvesting; and the design must allow for both faecal solids storage and the infiltration of the flushed liquid directly into the soil.

• Number of users (P): 6 people
• Design life (N): 10 years
• Solids accumulation rate (r): 0.05 m³/person/year
• Soil type: Sandy loam
• Infiltration rate (q): 30 L/m²/day
• Wastewater load: 2 L/person/day (light use) = 12 L/day total
• Selected diameter (D): 1.0 m

Step 1. Calculate Solids Storage Volume:

 

$$V_s=P\; \times \mathrm{r}\times \mathrm{N}$$ 

 

$$V_s = 0.05 \times 6 \times 10 = 3.0\ \text{m}^3$$ 

Step 2. Calculate Required Infiltration Area (Ai):

Ai = Volume of liquid per day / Infiltration rate

 

$$A_i=\frac{12\text{L/day}}{30{\text{L/(m}}^2\text{/day)}}=0.4{\text{m}}^2$$

 

Note: convert units to be consistent. Convert L → m³ or keep L and L/(m²·day).

 

Step 3. Calculate Effective Depth for Infiltration (Hi):

 

$$A_i = \pi D \, H_i \quad\Rightarrow\quad H_i = \frac{A_i}{\pi D}$$

​​

$$H_i = \frac{0.4}{\pi \times 1.0} \approx 0.127\ \text{m}$$

 

Step 4. Calculate Effective Depth for Solids:

We know:

$V = A \times H$

 

For a circular pit, the base area

$A = \frac{\pi D^2}{4}$

 

Solve for solids depth (Hs)

$H_s = \dfrac{V_s}{A} = \dfrac{V_s}{\pi D^2 / 4}$

 

$$A = \frac{\pi (1.0)^2}{4} = 0.7854\ \text{m}^2$$

 

$$H_s = \frac{3.0}{0.7854} \approx 3.82\ \text{m}$$

 

Step 5. Calculate total pit depth, including infiltration height, and add a freeboard:

 

$$\text{Total depth}=H_s+H_i+\text{freeboard}$$

 

Freeboard (recommended) = 0.5 m

 

$$\text{Total depth}=3.82+0.127+0.5\approx 4.45\text{m}$$

$$\text{Total depth} = 3.82 + 0.127 + 0.5 \approx 4.45\ \text{m}$$

Gender and Inclusive Access in WASH Design

When selecting water, sanitation, and hygiene (WASH) technologies, it is essential to look beyond technical efficiency and cost considerations. Local cultural norms, social habits, and user preferences must also be taken into account. Sanitation facilities that do not align with cultural expectations are frequently neglected or left unused, no matter how advanced their technical design may be. For instance, some communities favour squat toilets over sit-down models because of established beliefs about hygiene, comfort, or cleanliness. In contrast, others may prefer wet sanitation systems that enable water-based cleansing instead of dry systems reliant on toilet paper. The sanitation solution relies on adopting technologies that honour and incorporate local customs, making systems both practical and acceptable within the community [11,12].

Cultural factors also influence hygiene practices, including handwashing with soap. Beliefs about cleanliness, water use, or the perceived value of soap can affect uptake of hygiene interventions. Effective hygiene promotion must therefore engage with local knowledge systems, languages, and social norms to support long-term behaviour change, rather than relying solely on health messaging [13].

Women and girls often face extra challenges when using shared or public toilets, such as a lack of privacy, safety concerns, and social stigma. If sanitation facilities lack separate areas for women and men, secure locks, adequate lighting, or water for washing, this can discourage use and increase the risk of harassment. Menstrual hygiene management is also crucial; women and girls need safe, private spaces, water, and proper ways to dispose of or clean menstrual materials. Ignoring these needs can harm their health, dignity, and ability to attend school [14]. Humanitarian engineers must consider these requirements, including extra water for menstruation and culturally appropriate disposal, when designing water and sanitation systems.

Sanitation and hygiene facilities must be usable by everyone, including children, older adults, pregnant women, and people with disabilities. Obstacles such as steep steps, narrow doorways, uneven ground, or awkwardly placed taps can prevent vulnerable individuals from accessing these services safely. Features such as ramps, handrails, correctly positioned taps and toilet seats, slip-resistant surfaces, and clear signs help ensure fair access and allow people to use facilities independently. Designing WASH systems to be inclusive not only supports human rights but also strengthens the long-term effectiveness and sustainability of these services (see the following case study on community co-design and examples like Fundación Tierra Grata in the video below).

References

[1] Sphere Association, The Sphere Handbook: Humanitarian Charter and Minimum Standards in Humanitarian Response, 4th ed. Geneva, Switzerland: Sphere Association, 2018. [Online]. Available: https://spherestandards.org/handbook/

[2] D. Domullodzhanov and R. Rahmatilloev, “Development of low-cost rainwater harvesting to support on-site water supply in rural Tajikistan,” Central Asian Journal of Water Research, vol. 9, no. 2, pp. 103–120, 2023, doi: 10.29258/CAJWR/2023-R1.v9-2/103-120.eng.

[3] World Health Organization, Guidelines for Drinking-water Quality, 4th ed. Geneva, Switzerland: WHO, 2017. [Online]. Available: https://www.who.int/publications/i/item/9789241549950

[4] Food and Agriculture Organization of the United Nations, “Water quality monitoring, standards and treatment,” in The Fishery Harbour Manual on the Prevention and Control of Pollution, ch. 2. [Online]. Available: https://www.fao.org/4/x5624e/x5624e05.htm

[5] J. Davis and R. Lambert, Engineering in Emergencies: A Practical Guide for Relief Workers. Rugby, U.K.: Practical Action Publishing, 2002.

[6] World Health Organization, Guidelines for Drinking-water Quality: Fourth Edition Incorporating the First Addendum. Geneva, Switzerland: WHO, 2017. [Online]. Available: https://www.who.int/publications/i/item/9789241549953

[7] New Zealand Treasury, “North Island Weather Events response and recovery funding,” Jun. 17, 2024. [Online]. Available: https://www.treasury.govt.nz/information-and-services/nz-economy/climate-change/north-island-weather-events-response-and-recovery-funding

[8] S. S. Chang and R. C. Andrews, “Effect of chlorine dose and contact time on microbial inactivation,” Water Research, vol. 32, no. 3, pp. 679–685, 1998, doi: 10.1016/S0043-1354(97)00205-7.

[9] U.S. Environmental Protection Agency, Alternative Disinfectants and Oxidants Guidance Manual, EPA 815-R-99-014, Washington, DC, USA, 1999. [Online]. Available: https://nepis.epa.gov/Exe/ZyPDF.cgi/P1009BZL.PDF?Dockey=P1009BZL.PDF

[10] G. A. Norris, Sludge Build-up in Septic Tanks, Biological Digesters and Pit Latrines in South Africa, WRC Rep. No. 544/1/00. Pretoria, South Africa: Water Research Commission, 1999. [Online]. Available: https://www.wrc.org.za/wp-content/uploads/mdocs/544-1-00.pdf

[11] World Health Organization, “Water, sanitation and hygiene: Burden of disease,” Global Health Observatory Data. [Online]. Available: https://www.who.int/data/gho/data/themes/topics/water-sanitation-and-hygiene-burden-of-disease

[12] L. Fewtrell and J. M. Colford Jr., “Water, sanitation and hygiene in developing countries: interventions and diarrhoea—a review,” Water Science and Technology, vol. 52, no. 8, pp. 133–142, 2005.

[13] V. Curtis, W. Schmidt, S. Luby, R. Florez, O. Touré, and A. Biran, “Hygiene: new hopes, new horizons,” The Lancet Infectious Diseases, vol. 11, no. 4, pp. 312–321, 2011, doi: 10.1016/S1473-3099(10)70224-3.

[14] UN Women, Gender Equality in the 2030 Agenda: Gender-Responsive Water and Sanitation Systems, Issue Brief. New York, NY, USA: United Nations Entity for Gender Equality and the Empowerment of Women, 2018. [Online]. Available: https://www.unwomen.org/en/digital-library/publications/2018/6/issue-brief-gender-responsive-water-and-sanitation-systems

[15] Fundación Tierra Grata, “Home.” [Online]. Available: https://tierragrata.org/en/home

About the authors

name: Dr Bryann Avendaño-Uribe

institution: University of Canterbury

website: https://oer.pressbooks.pub/humanitarian-engineering/front-matter/about-the-editor/

Dr Bryann Avendaño-Uribe is a knowledge broker and former Postdoctoral Research Fellow and Guest Lecturer in Humanitarian Engineering at the University of Canterbury, New Zealand. He holds honours bachelor’s degrees in Science—Biology and Ecology—plus continuing studies certificates in Business and Leadership from Georgetown University (USA) and Modelling and Simulation from CIRAD, Montpellier (France), and a PhD in Civil and Environmental Engineering from the University of Canterbury. His research centres on participatory modelling and community engagement for humanitarian engineering, with a focus on developing facilitation tools to translate complex scientific knowledge for non‐scientific audiences. Dr Bryann’s work addresses climate change adaptation, disaster risk reduction, resilience planning, and environmental education, with a strong emphasis on co‐creation with communities. He actively advocates for scientific education policies and STEM education through his co-founded think tank, Scientelab.

name: Dr Ricardo Bello-Mendoza

institution: University of Canterbury

website: https://profiles.canterbury.ac.nz/Ricardo-Bello-Mendoza

Dr. Ricardo Bello-Mendoza is an Associate Professor and co-director of the Humanitarian Engineering programme in the Department of Civil and Environmental Engineering at the University of Canterbury, New Zealand. He earned his Bachelor’s degree (1991) at the Instituto Tecnológico de Tapachula in Mexico, followed by an M.Phil. (1997) and Ph.D. (1999) at the University of Manchester, United Kingdom. Dr. Bello-Mendoza’s research expertise lies in innovative technologies for wastewater treatment and resource recovery. He is currently investigating biosand filtration as an appropriate technology for rainwater treatment in Tonga, contributing to sustainable solutions that improve drinking water quality and protect community health in this Pacific Island nation. Before joining the University of Canterbury, Dr. Bello-Mendoza served as an Investigador Titular at El Colegio de la Frontera Sur (ECOSUR) in Mexico from 2000 to 2023. He has been part of the University of Canterbury academic community since 2013, initially as a Senior Lecturer before his current appointment as Associate Professor.