As the United Nations says is its 13th SDG, to face the impacts of climate change, the challenge for society is to lay the foundations for an emissions-neutral economy and accompany the most vulnerable groups in the transition process.
The availability and sustainable management of water and sanitation for all people are fundamental for the development of society and for the fight against poverty and disease anywhere in the world.
This challenge, in sanitation, focuses on the aspect of sustainability and is specified in the following challenges:
- Population growth, which is accentuated in large cities and in coastal areas, posing a problem because in Sanitation the networks are branched and grow outwards, lengthening the final branches and connecting other new branches to them, the main branches not being and general collectors planned for these new flows that reach them.
- The adverse rainfall, with more and more occasional periods of torrential rains of great intensity, represents a problem for sanitation because the networks are mostly unitary (sewage and rainwater together) and must be dimensioned to withstand those episodes of high rainfall intensity.
- The flatness of some areas of the cities, where the water in the sanitation networks flows by gravity, that is to say, “downwards” so that in a flat city it means that, if possible, the pipes must be deepened more and more, and if not possible, installing successive pumps that raise the water so that it can go back down.
- The decrease in the water table, due to the overexploitation of the aquifers and the increasing waterproofing of the land when urbanizing it, causes subsidence of the land and even the collapse of pavements and buildings.
- Urban development near the sea, since the sea, represents a natural barrier to the growth of networks along and in-depth. In addition, the rise in sea levels due to climate change produces marine intrusion in the land and therefore in the collectors that, in addition to increasing the transported flow and hindering the evacuation, make their treatment difficult due to the rise in salinity.
The solutions to face these challenges must focus on the long-term sustainability of the integral water cycle service, and that for Sanitation are multiple and varied, such as:
1. Modernization of sanitation management
With new technologies to optimize resources, reduce impacts on the environment, and improve the sustainability of the service, etc … through proposals such as:
- Use of Artificial Intelligence Systems through “Machine Learning” with algorithms based on neural networks “that predict failures in networks and facilities, to define the probability of failure and the criticality of each one and thus be able to optimize the asset management of infrastructures (GPI ), improving the planning of renovation work and optimizing the necessary financial resources and their environmental impact.
- Control of infiltrations in the Sanitation networks due to the water table, the large number of irrigation ditches, and the proximity of the Sea. For this, the internal inspections of the collectors must be increased by means of robots with TV cameras and the number of sensors increased level, flow, and quality. This will allow us to detect, locate and quantify infiltrations, and thus be able to define repair and renovation strategies, anticipating the collapse of collectors and reducing transported flows to reduce pumping and treatment costs in WWTPs.
- Real-time management of human and material resources, through the integration in a single platform of the different sanitation management systems such as GIS, Telecontrol, sewer inspections, corrective and preventive maintenance, scupper cleaning, etc. … This integration will allow the sharing of all company data (Big Data) in a single repository, enabling the creation of strategies and tools to transform that information into knowledge (Business Intelligence), and facilitating rapid intelligent decision-making through expert systems ( Artificial Intelligence), which are so necessary, especially in episodes of climatic emergencies and polluting discharges.
2. Development of infrastructures to control and improve the quality of discharges to receiving environments
- Deposits or storm tanks: construction of large tanks at the confluence of the collectors of urban watersheds, where the water from the collection of the first minutes of rain is stored, so that it is not discharged through the relievers to public channels, since they are highly polluting because they are the ones that clean the sidewalks and pavements of the streets in the episodes of rain. Once the storm has passed, these volumes of water are pumped to the treatment plants for treatment.
- Remote control stations of the reliefs made by the sewage and rain networks to the receiving channels, which, in compliance with the European directive, control the moment of the start, the duration, the flow rate, and even the quality of the discharge made. These stations, located in the spillways and outfalls, consist of level, flow, and quality sensors, connected to remote stations that send alarms and signals to the control center that records the data and manages the alarms through a modem.
3. Urban Sustainable Drainage Systems
Urban Sustainable Drainage Systems that aim to reduce the amount of water from the final discharge and improve the quality of the water discharged into the natural environment, with stormwater management techniques and urban planning and that imitate hydrological processes in urban development, controlling the runoff in the urban landscape through forecasting, through:
- Prevention: first, non-structural measures should be applied to prevent runoff water pollution, such as controlling the application of herbicides and fungicides in parks and gardens.
- Stop: control of runoff water in its place of origin or surroundings, using, for example, structural measures such as green roofs or paving.
- Slow down: reduce runoff through urbanized land, drains, strips, or infiltration areas.
- Store: runoff water is stored, using structural elements such as cisterns, ponds, surface or buried deposits, artificial wetlands, cistern covers, or buried storage areas. And use saved water after filtration.
- Infiltrate: finally, the stored water is infiltrated into the ground or reused, using structural elements such as infiltration ditches, bioretention strips, wells, and infiltration tanks.
4. Decarbonization
Decarbonization or reduction of CO 2 emissions from vehicle fleets, through:
- Evolution of the use of fleets of vehicles with zero emissions such as electric and hydrogen, or those with fewer emissions such as hybrids and natural gas.
- Development of charging networks for vehicles with energy supplies from renewable sources.
- Geolocation and control of fleets for the optimization of routes and use and thus reduce the kilometers traveled.
5. Use of renewable energies in the installations of the sanitation systems.
- Photovoltaic energy for self-consumption in offices, recharging vehicles and pumping facilities, and if possible, injection into the network.
- Hydraulic energy through microturbines in the pipes takes advantage of the kinetic energy of the water and even transforms it into electrical energy.
- Wind energy through micro wind turbines that feed the remote control systems of the sensors and remotes installed in the network.
6. Improvement of processes in the facilities for optimization of resources
- Renewal of motors, equipment, and electromechanical systems, by replacing them with more energy-efficient systems and renewing the wiring with others with a larger section and lower energy losses.
- Use of technologies that allow a user to visualize part of the real world through a technological device with graphic information added by it, called augmented reality systems, to assist and monitor the employees who perform the maintenance of the facilities.
7. Reuse of water, to reduce the use of natural sources.
- Alternative uses for the effluents after the purification process, through specific treatments and transport networks to take advantage of it in garden irrigation, street washing, ecological contributions to sensitive receptors, recovery of groundwater levels, etc.
- Use of state-of-the-art vehicle fleets in sanitation cleaning equipment with water recirculation systems.
8. Public awareness and communication through:
- Advertising campaigns to reinforce messages for the correct use of sanitation infrastructures (proper disposal of waste such as wipes and others, etc.).
- Open days in facilities for students of schools and institutes for training and awareness from childhood.
- Work placement campaigns for Vocational Training and University students.
9. Drafting and development of Sanitation Master Plans
Plans based on all the information obtained by the previous solutions, define when and what works will have to be carried out, both for the renewal of obsolete networks, as well as for storm tanks, and for new collectors and expansion of existing ones, and even network renewal.
