Water treatment systems

VEHA - Field Implementation Guidance

Welcome

Water supply, Sanitation and Hygiene Promotion (WASH)

Access to water for human consumption

Water extraction for water consumption and hygiene activities

Water treatment systems

Context

Overview

Environmental factors causing/contributing to the needs and affecting the humanitarian activity

As with all infrastructure, water treatment systems can have negative or beneficial impacts on the environment. The use of fossil fuels to power water treatment equipment will release greenhouse gases, contributing to climate change. The use of renewable energy supplies can eliminate this. The use of chemicals for water treatment to adjust pH, ani-foaming agents, coagulants, and flocculants, if not well managed, can all harm local flora, fauna, and aquatic systems. Wastewater from water treatment plants often significantly influences the receiving water course’s ecosystem as the quantity of organic matter is more concentrated.

However, water treatment systems can be designed to minimise environmental impacts including the design of gravity-fed systems, using less or zero electricity, including the use of gravity filters and reed beds, and even fish to help treat water at different points in the treatment process.

Implications

Gender, age, disability and HIV/AIDS implications

People living with chronic or terminal illnesses, the very old and very young, are more vulnerable to water-borne disease than others.

Impacts

Environmental impact categories

Air pollution
Soil pollution
Water pollution
Climate change
Loss of biodiversity and ecosystems
Soil Erosion

Summary of Impacts

Summary of potential environmental impacts

Air pollution due to the usage of fossil fuels for water treatment.

Water and soil pollution due to spills of chemicals used in water treatment.

Water and soil pollution due to by-products from water treatment processes. Disinfection byproducts are chemical, organic, and inorganic substances that can form during a reaction of a disinfectant with naturally present organic matter in the water.

Negative effects on water bodies due to installation of water treatment equipment/infrastructure.

Impact detail

Detailed potential environmental impact information

Advanced treatment systems consume large amounts of energy which can make them costly and environmentally unfriendly if using diesel generators or other fossil fuels for local electricity grids. For example, the use of generators or local power stations can create air and noise pollution from combustion, mainly due to carbon dioxide (CO2) and water vapor (H2O) products, but also from particulates from coal and diesel.

Surface water sources, whether stationary or flowing, and groundwater sources, are vulnerable to pollution, from spillages as well as from upstream pollution and any surface water infiltration.

Water treatment by-products can form when disinfectants, such as chlorine, react with naturally present compounds in the water. The formation of these products mainly takes place during reactions in which organic substances play a part.

Disposal of water treatment residuals – e.g. when using aluminum sulfate for water treatment, requires careful planning and identification of what to do with the residual which is a strong concentration of Alum. If this Alum concentrate contaminates water sources it can have a detrimental impact on health. This is important as Alum is used in many water treatment systems.

Construction works disrupt soil, create waste, and can pollute the air, soil, and water. Flora and fauna living within aquatic ecosystems can be very sensitive to minor changes in water turbidity, oxygen levels, water color, odor, and any pollutants.

Guidance

Summary

Summary of environmental activities

Use low energy consumption technologies or introduce renewable energy sources (for example low-tech windmill type pumps in areas of regular wind, solar panels, or bicycle pumps).

Properly store and seal non-water liquids that can contaminate water sources and soil and identify the chemicals and possible environmental impacts.

Create a strategy to ensure the regular inspection of and identification of expired or contaminated water treatment chemicals/by-products and to ensure their safe disposal.

Plan construction works on, or adjacent to water very carefully to ensure that construction, installations of new equipment, or maintenance of existing infrastructure do not allow water pollution and contaminants from works negatively impact surrounding ecosystems

Detail

Detailed guidance for implementing suggested environmental activities

Renewable energy options should be explored in both temporary and permanent solutions and low energy consumption designs should be explored for both short and long-term facilities.

Locating water treatment at higher elevations reduces energy consumption during operation as gravity can be leveraged for flow distribution and minimizes the need for constant operation of pumps, thus reducing energy usage.

The environmental, social, and economic impacts of electricity production should be considered, and appropriately prevented or mitigated. Include workshops and policy support on the technology used to facilitate uptake by local authorities and the private sector.

The design of the system should not allow the (re)entry of any chemicals or treated water back to the source. If chemicals are used, a proper storage location and containers should be identified or constructed to prevent leakages from entering the environment. In addition, special care must be applied to water leaking into stores of powdered chlorine for example. Operators must be well trained in chemical storage and in what to do in the event of a spillage.

Strategies to ensure the regular inspection of and identification of any expired or contaminated or reacted substances relating to water treatment should be put in place together with procedures for its safe removal and permanent disposal in order to avoid the pollution of nearby water sources and soil. Safe disposal in sealed containment within high-quality landfill which is carefully capped with thick deposits of clay or geomembranes to prevent water ingress or leachate egress – to ensure it does not contaminate surface or groundwater including in the event of any flooding. Temporary storage in sealed bunded containers is often employed but this is not a permanent solution.

Review energy requirements for UV treatment of water and the circumstances under which UV treatment can/cannot be used. It is also necessary to think about environmental legacies such as pollution with heavy metals or agrochemicals.

Wherever possible, construction in sensitive areas should be avoided. Where they do proceed, expert advice, informed by a good understanding of the local environment, must be sought to minimise environmental impacts.

Land use should be planned carefully to avoid unnecessary encroachment into natural ecosystems, which also risks the transmission of diseases between animals and humans.

When conducting any work near surface water, protect banks to avoid erosion and eventual spills that could deplete the source. For example, when building intake structures protect the banks on either side against scouring.

When new equipment is being installed or there are maintenance works, ensure that contaminants cannot be released into the water or surrounding environment.

Obtain maps of sensitive ecosystems from the ministry of environment. If developing new approaches to construction, ensure they are not polluting and train and certify local contractors, and monitor their work to ensure it is sustained. Work with local government to promote more environmentally beneficial construction methods and encourage their incorporation into government policy and/or contingency plans.

Lessons Learnt

Lessons from past experiences

Most of the world’s cities struggle with high levels of air pollution from vehicles, factories, offices, households, and other activities. This includes fossil fuels used for pumping water to large populations.

Uncontrolled water of chemicals for water treatment results in spillage and soil and water pollution in many countries and contexts. Improvements to storage, training, and use, reduce pollution.

By products from water are less substantial than those from sewage treatment, however, they still cause pollution. If this is not managed well then was pollutes watercourses.

European standards for water treatment facilities have been increased due to pollution of watercourses from water treatment. This includes impacts on sensitive ecosystems, harm to fish breeding sites, and disruption.