Water treatment

A Guide for Integrated Conservation & Sanitation Programs & Approaches

Purpose of the document

Human and ecosystem health are inextricably linked, yet strategies to improve both are addressed in siloed ways (Wakwella et al., 2023). For instance, the water, sanitation, and hygiene (WASH) sector focuses on the provision of services for safe drinking water, sanitation, and hygiene to improve human health and wellbeing. However, although there is substantial evidence to show that unsafely managed sanitation degrades ecosystems and makes them more vulnerable to climate change (Wear et al., 2023), and that ecosystem loss and degradation negatively impacts human health (Herrera et al., 2017; Wakwella et al., 2023), the sanitation and conservation sectors rarely work in a coordinated and strategic way to achieve their interconnected goals.

The Science for Nature and People Partnership (SNAPP) Improving Coastal Health working group formed in 2020 to develop resources to help marine conservation and sanitation practitioners work together on integrated conservation and sanitation programs. Informed by the outcomes of a needs assessment launched in 2021 to better understand the challenges and opportunities related to integrated programs, we created this document as a first step towards providing advice on implementing integrated conservation and sanitation programs.

The purpose of this guide is:

• Biodiversity conservation: To ensure the protection and sustainable management and use of biodiversity, so as to maintain threshold levels that allow diverse organisms to thrive in the future through natural processes, such as natural selection and evolution (Jaisankar et al., 2018).

• Blackwater: A waste stream from toilets that is the mixture of urine, feces, flush water, and cleansing materials (e.g. toilet paper) (Fig. 1). Blackwater contains pathogens (mainly from feces) and nutrients that are diluted in the flush water (Tilley et al., 2014).

• Coastal and marine ecosystems: Ecosystems located in the land-sea interface (Ayyam et al., 2019). The present guide focuses primarily on tropical ecosystems such as mangroves, seagrass, and coral reefs, but refers to other coastal ecosystems where relevant.

• Contaminants vs. Pollutants: Contaminants are considered chemical elements or compounds that are present at concentrations above background or that should not be present. A pollutant is a contaminant that is found at concentrations that cause adverse biological effects in living beings (Chapman, 2007).

• Ecosystem health: The state or ability of ecosystems to maintain their organization, structure, and functions needed to deliver ecosystem services, and manage external stress through time (Costanza, 1992).

• Ecosystem services: The ecological functions or processes that directly or indirectly contribute to sustainable human wellbeing (Costanza, 2020).

• Excreta: Urine and feces combined with any flushing water (SuSanA, 2018).

• Fecal sludge: Excreta collected via non-sewered sanitation systems, such as pit latrines, leach pits, and septic tanks (SuSanA, 2018).

• Greywater: Water generated from washing food, clothes, and dishware, as well as from bathing, but not from toilets. It may contain traces of excreta (e.g., from washing diapers) and pathogens (Tilley et al., 2014).

• Latrine back-end: The containment facility where fecal waste is stored, treated, or disposed (Tilley et al., 2014).

• Natural resources: Materials or substances occurring in nature which can be exploited for economic gain. This term differs from ecosystem services in that ecosystem services are the benefits provided to humans through the transformation of resources (or environmental assets, including land, water, vegetation and atmosphere) into a flow of essential goods and services e.g. clean air, water, and food. As an example, an ecosystem service provided by coastal marine ecosystems is the support and maintenance of fish populations, which can then be extracted as a natural resource.

• Nature-based solutions: For this guide, it refers to the planned and deliberate use of ecosystems and ecosystem services to improve water quality or quantity, and to increase resilience to climate change (UNEP-DHI et al., 2018).

• Non-sewered sanitation systems: All on-site sanitation systems that are not sewered. This typically includes leach tanks, septic tanks, aerated treatment units, cesspools, and pit latrines. In the sanitation sector, all excreta that is collected in on-site systems is called fecal sludge, but for septic tanks an additional term of septage is sometimes used. Fecal sludge can
be removed/ transported and treated in fecal sludge treatment plants or other treatment facilities, such as sludge drying beds. The term wastewater is used in this guide to describe excreta from on-site systems. In the case of septic tanks, any treated septage discharged via drainage fields is termed treated wastewater in this guide (Fig. 1).

• Pharmaceutical and personal care products: These include numerous groups of chemicals used to treat or prevent animal and human disease, or chemicals contained in personal care products such as shampoos and deodorants (Boxall et al., 2012). They are consistently associated with sewage and wastewater (Meyer et al., 2019) and are classed as Contaminants of
Emerging Concern (Hoyet, 2018).

• Receiving environment: the natural environment that receives any discharge of waste, including from leaching, runoff, and discharge of treated and untreated wastewater.

Data type
Research report
Research and monitoring
Geographic location
St. Eustatius
St. Maarten

Spatial and Temporal variation of Chlorophyll-a and nutrients in coastal waters of Saba

Anthropogenic stressors such as improper wastewater treatment, dump sites and construction sites can increase nutrient input into marine coastal waters, thereby declining water quality conditions for coral reefs and the surrounding marine environment. Increased nutrient flow in the form of dissolved inorganic nitrogen (DIN) and phosphorous (DIP) is taken up by phytoplankton leading to enhanced algal and cyanobacterial growth which can be measured by an increase of Chlorophyll – a (Chla). As part of the project, “Restoration of Nature and Resilience in the Dutch Caribbean”, water quality monitoring has been implemented on Dutch Caribbean islands to determine local stressors effecting costal water quality. Thus far, the role of land-based nutrient pollution has not been assessed on the Dutch Caribbean Island, Saba. This report analyses the water quality surrounding Saba’s coastal waters with a focus on Chla and nutrients and their relation to anthropogenic stressors on the island. We analysed the distribution of Chla and nutrients spatially and temporally. It is shown that Chla frequently exceeds the 0.2-0.3μM threshold around the harbour and in the two bays: Well’s Bay and Spring Bay/Cove Bay. Temporally, the highest elevated values can be attributed to the hurricane season form August-October. The first round of nutrient sampling from the week of 25-05-2022 shows that DIN exceeds its threshold for Cove Bay and Tent Reef, with ammonium contributing the largest to the DIN content. In future, attention needs to be paid to the DIN and DIP balance since high elevated ratios have been found at Tent Reef, possibly indicating DIP - limitation. With only one week of nutrient data available, no correlation between Chla and nutrients could be made. Overall, sites such as Tent Reef, Well’s Bay, and Spring Bay/Cove Bay demonstrate the most severely declining water quality based on frequently elevated Chla and nutrient levels. Further research on water quality data surrounding Saba is necessary to confirm these findings and to address stressors contributing to decreased water quality.

Data type
Scientific article
Research and monitoring
Geographic location