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Protecting residents from sanitary hazards – HST solutions for combined sewers

The combined sewerage system discharges domestic sewage and rainwater through a common channel. Therefore, in the event of overflows, e.g. during heavy rains, there is a serious risk of exceeding the capacity of the treatment plant and discharging untreated wastewater to the receiving water body. Sludge removal systems and HST flow control devices can provide a solution to such problems.

  • Sanitation risks posed by wastewater decay
  • Technology to prevent wastewater decay
  • HST equipment and comprehensive support from Ecol-Unicon
  • AWS Jet Cleaner aeration and flushing nozzle
  • AWS Flush Gate

Sanitary wastewater decay is a serious sanitary risk

Sewage decay and the accompanying noxious odours are caused by oxygen deficiency in extensive sewer systems and long delivery pipelines. This occurs after the wastewater has been in the pipeline for only a few hours, and its consequences can be hazardous to the health and lives of both residents and maintenance crews. At the same time, treatment of such wastewater becomes less efficient and more energy-intensive.

Insufficient aeration of wastewater results in wastewater decay. It leads to the oxidation of hydrogen sulphide and the formation of sulphuric acid, which is harmful to the wastewater network components.

Hydrogen sulphide causes corrosion of concrete and metal structures and equipment. It also contributes to the foaming of wastewater and the growth of filamentous bacteria and aerobic chemotrophic sulphur bacteria. It is the gas that causes the most poisoning and deaths among workers associated with the operation of water and wastewater systems. It is particularly dangerous because it cannot be smelled in high concentrations.

Technologies to prevent decay of wastewater

Contrary to expectations, the investment and operating expenses of solutions aimed at preventing wastewater from decay are not high and should already be foreseen at the design stage of the sewage system. They make it possible not only to operate the wastewater treatment plant more efficiently, but also to seriously reduce operating costs.

The most common systems used are aeration of wastewater or disposal with air or water, such as:

  • pipeline blowing with compressed air
  • aeration of wastewater with compressed air
  • water flushing

Another solution used is the application of chemical agents that bind hydrogen sulphide compounds or inhibit bacterial growth. However, this method generates higher costs and increases the risk of corrosion of concrete or metals. It also requires appropriate dosing pumps and equipment to measure the concentration of hydrogen sulphide. In addition, chemical compounds such as nitrates or iron salts are not completely removed during wastewater treatment and may end up in the environment.

HST devices and comprehensive support from Ecol-Unicon

German-made solutions from HST Systemtechnik, such as sludge removal systems, keep sewer networks in optimum condition. These are innovative and effective products that integrate information technology into the operation and management of facilities.

The exclusive distributor of HST products in Poland is Ecol-Unicon, a company that, together with its German partner, provides comprehensive services from the design itself, through the implementation stage, to service.  Ecol-Unicon offers full support in planning, consultancy, assessment, dimensioning or planning documentation of the entire water and sewage system.

AWS Jet Cleaner aeration and flushing nozzle

The AWS Jet Cleaner aeration and flushing jet is a powerful and highly efficient pump with nozzle set. It can be used in combined sewers, wastewater treatment plants, storage tanks and in process water treatment.

The AWS Jet Cleaner produces a water-air mixture as a driving and cleaning jet. This effectively eliminates wastewater decay processes during prolonged retention.

It is a fully automatic cleaning unit which, in its standard version, consists of a pump unit and a set of injectors. The AWS rotary nozzle is equipped with a set of injectors, which allow a large flushing radius even with very different tank geometries. The contaminants are discharged here as the tank is emptied. During the emptying process, the nozzle operates in intermittent or continuous mode, according to predetermined switching points. In addition, cleaning is assisted by rotating movements.

The HydroMatic software used in the streamer allows for energy-efficient control of the entire process with real-time monitoring of the results. It is also possible to individually adapt the operating mode of the unit to local conditions.

Flushing efficiency data is continuously recorded by a screen located at the bottom of the tank. This makes it easy to monitor the effectiveness of ongoing activity. The location and intensity of sludge can be determined by entering the data manually into the control panel or automatically using an optical camera.

AWS Flush Gate

AWS Flush Gate is an extremely effective and fully automatic system used to remove sludge from combined sewers and holding tanks. It works by using sensors mounted in the tanks and relies on the use of stored water to flush the bottom of the tank. Opening the manhole creates a strong wave that safely flushes out accumulated sludge.

A chamber closed by a flap is placed above the section that requires flushing. This allows the chamber to be opened automatically when it is required to remove the sludge from the system. For the remaining time, water is stored in the chamber, ensuring that the sewer can be cleaned even in dry weather.

Thanks to its lightweight housing and compression system, the AWS Flush Gate does not require additional delayed closing mechanisms, minimises hydraulic losses and allows the tank to be completely emptied.

You can find more about the equipment supporting HST’s combined sewer solutions on our website. We also invite you to sign up to our newsletter to keep up to date with all the latest news from the wastewater industry.

Due to climate change, we are increasingly experiencing catastrophic phenomena such as violent storms, heavy rains or prolonged periods of drought. These are not only disruptive in cities, but also seriously affect farmers, determining the size, quality and price of crops. Agriculture is an extremely water-intensive economic sector. It is therefore not surprising that rainwater retention solutions are increasingly being sought here too, in order to conserve water resources.

  • Hydrological situation and retention potential in Poland
  • New regulations for the benefit of farmers
  • Innovative HYDROZONE solutions – the antidote to agricultural drought

Hydrological situation and retention potential in Poland

According to the UN, the limit below which a country is considered at risk of water scarcity is 1700 m3 per capita. In Poland, this value has not exceeded 1600 m3 for years, which gives it one of the last places in Europe[1]. Our resources are not only very scarce, but are additionally affected by high seasonal and area variability.

Meanwhile, still most of the precipitation, a major contributor to the water balance, ends up back in the atmosphere through evaporation. Only some of it infiltrates into surface and groundwater or is collected and reused.

There is no doubt that major investments in technology and water-saving solutions are needed. Rainwater management is not only an expression of concern for the environment and dwindling potable water supplies. It also represents tangible financial savings, which farmers are slowly beginning to realise.

It is estimated that the real retention capacity in Poland is 15% of the average annual outflow. For several decades we have not been able to exceed 6.5%. We only managed to do so two years ago. All thanks to increasing investments, subsidy programmes, but also an increase in environmental awareness[2].

Agricultural drought – a serious challenge for Poland!

The law is favourable to farmers

In addition to existing programmes and funds to support retention, legislation also seems to favour agricultural investment in this area.

Simplified regulations in force since this year allow the reconstruction of drainage systems without a water permit. It is also possible to construct retention ponds of up to 5,000 m2 in area and 3m in depth by notification only. In addition, according to Regulation 2020/741 of the European Parliament and of the Council of the European Union of 25 May 2020, it will be possible to reuse water from previously treated wastewater in agriculture.[3]

The project has been proceeding since 2018 with the aim of setting minimum quality standards for reclaimed water in EU member states. Its aim is to ensure sufficient water to irrigate fields, particularly during heat waves and severe droughts.

The new regulations are part of the circular economy. It is intended to help adapt to the consequences of climate change. The regulations will take effect from 26 June 2023. According to experts, the entry into force of the regulation could increase the use of water from wastewater from the current approximately 1 billion m3 per year to as much as 6.6 billion m3 in 2025.

Innovative HYDROZONE solutions – the antidote to agricultural drought

It turns out that simply by investing in the right tank, even more than 500 litres of rainwater can be collected during half an hour of rain. On a monthly basis, with an average rainfall of 650 mm, this yields up to 5 000 l of water!

The construction of multi-purpose retention tanks makes it possible to reuse treated wastewater for crop irrigation. This not only allows for lower consumption of limited surface and groundwater resources, but also great savings in the face of ever-increasing water prices.

HYDROZONE systems manufactured by Ecol-Unicon are a line of modern products addressing all rainwater and snowmelt retention needs. Their advantage is a modular design with additional equipment allowing to collect, but also to treat and reuse rainwater. Three variants are available: from basic retention functions to advanced water management.

HYDROZONE BASIC retention tanks with evaporation function are used to retain rainwater and snowmelt in the event of drought. They will also prove their worth in the prevention of waterlogging and flooding on farms.

The second type of tank, HYDROZONE CLEAN, additionally enables rainwater and snowmelt water to be treated before it is reused for crop irrigation. HYDROZONE BENEFIT, on the other hand, is a solution with a particularly high environmental performance. It includes features that allow the tank to be adapted to the very specific needs of each farmer.

The modular design of all HYDROZONE systems not only allows them to be easily adapted to the type of farm, but also greatly simplifies installation and day-to-day maintenance. They are equipped with a pretreatment system and, depending on your needs, can optionally include flow regulators, water refreshing jets or pumps to facilitate water extraction and watering.

Importantly, they are constructed using durable DZB reinforced concrete tanks, capable of withstanding high dynamic loads. Integral to the HYDROZONE tanks is the innovative Bumerang SMART system, which allows key data to be monitored and the operation of the facilities to be effectively controlled and managed.

[1] www.raportsdg.stat.gov.pl
[2] https://www.wody.gov.pl/attachments/article/1875/Raport%20Stop%20Suszy%20Wody%20Polskie_Od%20suszy%2050-lecia%20do%20wzrostu%20retencji.pdf
[3] https://eur-lex.europa.eu/legal-content/PL/ALL/?uri=uriserv:OJ.L_.2020.177.01.0032.01.POL&toc=OJ:L:2020:177:TOC

Periodic river flooding, whether as a result of prolonged rainfall or spring thaw, is perfectly natural in our geographical area. Unfortunately, in the face of serious climate change, we are increasingly confronted with dangerous torrential rainfall that leads to more serious phenomena such as flooding. We therefore need specific solutions to increase the retention and use of rainwater.

  • What is flooding?
  • Climate change and human interference with water management
  • Flood risk management
  • Modern flood protection – HYDROZONE retention tanks
  • HYDROZONE – implementations and benefits

What is flooding?

According to the definition adopted by the Water Law, flooding is to be understood as the temporary covering by water of land that is not normally covered by water, in particular caused by the surge of water in natural watercourses, reservoirs, canals and from the sea, excluding the covering by water of land caused by the surge of water in sewerage systems[1].

In reality, it is one of the most dangerous and violent phenomena, with huge economic, environmental and even human losses.

According to UN data, natural disasters account for more than 90 per cent of all major recorded events, and of these, floods, inundation and waterlogging are responsible for more than 40 per cent of the damages[2]. These dangerous and catastrophic phenomena are the result of severe climate change, but also of an irrational human economy.

On one hand, climate change has resulted in prolonged periods of drought, but also in extreme events such as heavy torrential rainfall. On the other, the development of riverbeds and increasing areas of impermeable surfaces, such as concrete plazas, paved roads or buildings, do not allow rainwater to naturally infiltrate into groundwater. Instead, they run off at a rapid rate causing the water level of rivers or reservoirs to rise rapidly.

Flood risk management

Flood risk obviously cannot be eliminated, but we can manage flood risk. On 23 October 2007. The European Parliament adopted the Floods Directive[3], which requires Member States to take measures to reduce the risk of flooding.

In Poland, protection against flooding is the responsibility of the State Water Management Company Wody Polskie (PGW WP) as well as the central and local government authorities. In accordance with the Floods Directive and the Water Law Act, flood risk management plans as well as hazard maps and flood risk maps are prepared periodically to increase the safety of the Polish population.

It is also necessary to coordinate measures within entire catchments so that those taken in the upper part of the catchment, such as construction of dykes, do not increase flood risk in the lower part.

When planning such activities, it is extremely important to use solutions to increase natural retention and protect environmentally neutral ecosystems. Natural retention will not only allow excess water to be retained in the event of heavy rainfall, but also to be used in periods of prolonged drought.

Modern flood protection – HYDROZONE retention tanks

HYDROZONE systems from Ecol-Unicon are an innovative approach to the retention problem. The distinguishing feature of such solutions is their modular design and the possibility to freely configure equipment elements to meet the needs of rainwater and snowmelt pretreatment, retention and utilisation.

The stored and pretreated rainwater is reused to wash streets, car parks, water green areas or flush toilets. It can also be infiltrated into the ground, significantly reducing the costs associated with lost retention charges. Our range includes water retention systems to suit different needs, such as BASIC, CLEAN and BENEFIT.

HYDROZONE – tangible solutions and benefits

HYDROZONE BASIC tanks were used, among others, during the construction of the Hillwood Łódź Górna logistics centre located in the southern part of the city. The facility consists of a large area of roofs and sealed surfaces, which required an appropriate rainwater collection system. Water entering the retention tank is successively pumped out into the storm sewer system, which provides a backup for the capacity of the entire system.

Two tanks founded in Józefów Street in Łódź have a capacity of 1,500 m3 and a length of almost 70 m. In addition, they are equipped with a pumping station consisting of a chamber and modern water treatment devices.

The HYDROZONE BENEFIT system, on the other hand, has proved its worth in Międzywodzie, a small coastal town. For years, residents there have struggled to cope with the effects of torrential rainfall along the coast and droughts in the northern part of the town.

The system, with a capacity of 115 m3, provides storage for water from rainwater systems and, through the use of additional water treatment modules, allows it to be used for other purposes, such as watering greenery.

Implementation of the HYDROZONE BENEFIT tank and the BUMERANG SMART system in Międzywodzie

HYDROZONE BENEFIT was also used in the construction of a floodplain polder in Rawicz. A prefabricated reinforced concrete retention tank with a capacity of 550 m3 was used to temporarily collect rainwater fed by the planned canal at Kadecka Street. It consists of flat closing modules, an extension module, internal supports and covers

The system comprises of an integrated mineral suspended solids and oil derivatives separator and two pumping systems. The solution effectively relieved the pressure on the existing rainwater drainage system and dewatered the surrounding area.

In turn, HYDROZONE BENEFIT modular retention tanks with a capacity of 500 m3 in Gorzów Wielkopolski made it possible to eliminate local flooding in the area of Szarych Szeregów Street, Ogińskiego Street, Prądzyńskiego Street, Sosnkowskiego Street, Jarocki Street and Załuskich Street. They also made it possible to regulate the management of rainwater and snowmelt in the WS-1 catchment area in the Szmaragdowa Street.

The BUMERANG SMART system was used in all systems. This is an innovative solution for monitoring the operation of equipment and facilities in water and wastewater systems, and is an integral component of HYDROZONE tanks. It not only enables better management of rainwater retention and use, but also economical and efficient management of the operation of the entire water and sewage network.

[1] Act of 20 July 2017. Water Law (Article 16(43))
[2] Economic Losses, Poverty & Disasters 1998-2017
[3] Directive 2007/60/EC of the European Parliament and of the Council of 23 October 2007

Concrete squares, trees cut down, tiny lawns and ubiquitous asphalt – this is more or less how most Polish cities look today. This phenomenon is called conretitis. The word perfectly reflects the nature of the problem, emphasising the almost morbid intensification of the trend of making the cities look concrete. Unfortunately, it is associated not only with a purely aesthetic issue, but also – or even primarily – with great difficulties for the Polish cities. Water drainage is inadequate, resulting in increasingly frequent flooding and inundation.

Concretitis – what does it actully mean?

In scientific and media discussions, as well as in public space, the word concretitis can be heard more and more often. The term, invented by Jakub Madrjas and popularised by Jan Mencwel, has become a symbol of the changes taking place in many Polish cities. Changes for the worse.

The trend to talk about concretitis in Poland began in 2019. It was then, during a summer heat wave, that Mencwel began publishing on Twitter a series of posts with photos of Polish town squares and urban spaces that, as part of an ill-conceived revitalisation, had turned from green squares into concrete-covered courtyards.

This has many unpleasant consequences. A simple thermometer test is enough to discover how rapidly the temperature rises in areas where trees have been felled. In the summer, trees serve as natural umbrellas that effectively protect us from the sun, giving us respite in the heat. Places without them become hotspots, deserts in which it is impossible to stand.

Trees provide shade, are great at storing water, inhibit street dust from entering homes, and filter the air. And these are just a few of their functions. Activists from the Krakow for Residents group took temperature measurements on streets planted with trees and those without. The conclusions are shocking. In certain spots without trees the temperature rises by as much as 20 degrees!

Floodingsof the Polish cities – where does the problem come from?

But the problem of tree felling is not everything. Concretitis is affecting the urban fabric in a wider context. Lawns are disappearing and being replaced by asphalt, cobblestones and other water-repellent materials. And this has serious consequences. One of these is flooding and flooding associated with heavy rainfall.

An example of poorly conceived revitalisation that has taken place in Poznań is the renewal of the Łazarski Square. Unfortunately, the modern design did not take vegetation into account, replacing it with geometric blocks and single flower pots.

Green-blue infrastructure

Urban concretitis is a disease that affects many cities, making it difficult for residents to function normally. Problems arise both in hot weather and during heavy rainfall. To stop this phenomenon, systemic measures are needed.

One of the changes Polish cities should make is to invest in green-blue infrastructure. This is based on a modern approach to climate change and the problems associated with it. As part of such work, localities are to change the way they are being developed. Green roofs, facades or elements related to sustainable water management should appear.

In urban, highly developed environments, these nature-based solutions (NBS) can support ecological activities. They can be successfully placed, for example, among elements of road infrastructure, in housing estates or office buildings. NBS are supposed to eliminate problems connected with concretitis in the cities by introducing elements necessary for reasonable management of, for example, water. In this way, a single element of such infrastructure can simultaneously contribute to safe rainwater collection, drainage and mitigation of urban heat island effects.

The Bydgoszcz revolution, a step towards a sustainable future

Bydgoszcz is one of the cities that have decided to carry out such a green-blue revolution. The city’s authorities decided to adapt it to climate change and invest more than 230 million PLN in the expansion of the rainwater system. Almost 20 kilometres of rainwater canals, numerous retention tanks and almost 30 rainwater treatment plants are currently being built.

A Hydrozone retention tank with a diameter of 8000 mm, a height of 5.4 m and an internal length of 17 m was installed in Bydgoszcz at Równa Street. The entire structure was made of high quality watertight concrete, and the capacity of the retention tank was 312 m3.

Construction of a rainwater retention tank on Równa Street in Bydgoszcz

Thanks to the changes that are taking place in the city, the problem of flooding and inundation will be reduced or perhaps eliminated altogether.

HYDROZONE retention tanks allow the retention, treatment and use of rainwater and snowmelt. There is also an increase in the possibility of safely draining excess water from city centres, which translates directly into more effective flood control measures.

This, fortunately, is already happening. More and more local authorities are recognising the importance of the problem and are starting to invest in green-blue infrastructure elements. And this saves us from the serious consequences of short-sightedness.

The world is running out of drinking water, so it is important to manage the available resources efficiently. The use of rainwater is becoming increasingly popular, both in households and in urban spaces.

By using rainwater in your household, you can reduce your water consumption by up to half. It is perfect for flushing toilets, cleaning, or watering the garden. On a larger scale, rainwater is used in agriculture, industry or for flushing sewage systems. Most often, retention reservoirs are used to collect precipitation, allowing water to be stored until it is actually needed. We decided to investigate and present interesting solutions for the use of rainwater in countries where the technology of rainwater harvesting has been perfected, reaping both the economic and ecological benefits.

New Orleans (USA)

In this city, a neighbourhood was built on previously drained, rather marshy land. Unfortunately, the site suffered during the famous Hurricane Katrina and was once again flooded. The authorities decided not to deal with the excess water in the area any longer and, after rebuilding the district, relied on the accumulation of rainwater. The Mirabeau Water Garden project was created and is currently being implemented. It will have a surface area of 100,000 square metres and the capacity to store around 35,000 square metres of water. Numerous mini-parks have also been created in this difficult area to collect water from the neighbouring plots.

Copenhagen – Tasigne Plads (Denmark)

Umbrella-shaped installations have been set up in the Copenhagen square to collect rainwater, which is then used to water the urban vegetation. In addition, the area has been deliberately landscaped so that the hollows with trees and flowers accumulate as much rainwater as possible, with any excess going into underground tanks.

Industrial estate in Kingston (Australia)

Three streets were renovated and their surfaces replaced with a permeable layer. New rain collectors were installed and 54 infiltration ditches were created along the roads. Special infrastructure was also created to collect water from roofs and streets, which feeds the underground retention tanks. The filtered rainwater is used to water the urban vegetation and is also pumped to hydrophytic systems where plants take care of its treatment. The Kingston Renewal provides annual storage of approximately 4,000 cubic metres of water.

Warrnambool (Australia)

Here, a comprehensive system was created to collect water from the housing estate’s roofs into an above-ground retention tank. In order to do this, a separate rainwater drainage system was run from each house, which then transports the water to the tank. The collected rainwater undergoes a treatment process in which it is given the quality of drinking water. Thanks to the measures taken in Warrnambool, more than 16 million litres of water are collected annually. This impressive amount is the equivalent of what the local population drinks in a year.

Houtan Park (Shanghai)

It is an example of a comprehensive use of space, not limited to the use of rainwater, but extending its properties to purify the air, filtering water from the surrounding river, protecting against floods and providing a place for leisure and recreation. Houtan Park was developed as part of the 2010 World Expo project on a brownfield site adjacent to the polluted Huangpu River. The park area has been arranged in a terraced and cascading manner, with lush vegetation developing on each floor, which filters river water and rainwater in a completely natural way, purifying and aerating it. The water thus collected is used in the Expo Park below.

Rainwater use in low developed coutries

While there are many examples of rainwater harvesting in rich countries, it is still not popular in low-industrialised countries. One reason for this is the very low rainfall in regions such as Central Asia, India and Africa. A second obstacle is the lack of funds to build retention tanks or implement systems to collect water from the roofs. Therefore, in underdeveloped countries, rainwater is used on a small scale, people collect it for their own use in domestic tanks and use it in everyday activities such as washing, washing and even personal hygiene. The water collected in this way is also used in local agriculture to irrigate fields.

Trees, both in the forest and in the city, play an important role in the hydrological cycle by reducing the risk of flooding. The retention of vegetation is able to effectively support not only soil retention, but also ground retention. This is because diverse vegetation simultaneously absorbs and stores moisture, actively participating in the infiltration process. Furthermore, it is largely responsible for avoiding soil erosion by slowing down surface runoff.

Ecological function of the forest

Rainwater retention – by means of the properties of the forest soil – has a positive effect on runoff. This is due in large part to the topsoil, which is protected by undergrowth, mulch, underbrush and, above all, tree crowns. This allows most of the rainwater to soak into the soil and then drain off very slowly. Thanks to the presence of highly absorbent organic soils, rainwater is still “looked after” for some time by the forest vegetation, especially trees.

Forests are responsible for the natural regulation of water relations, acting over vast areas to reduce the risk of flooding. Thus they have a great influence on agricultural crops and even on the water supply of cities, settlements and industrial facilities.

Natural retention reservoir

Forests, like peat bogs and soil, act as natural retention reservoirs, effectively protecting against floods which can cause huge damage. This is why it is so important to take care of vegetation that is able to collect and retain water. In the event of drought, the forest gives back the stored water, regenerating itself. At the same time, it is in charge of the rivers, guaranteeing biological flow. As a result, it is possible to obtain water for the industrial and agricultural purposes.

Fot. by Pixabay

Natural retention reservoirs are maintained by the State Forests staff, who additionally choose to enhance retention by reconstructing existing natural retention capacities. This is necessary so that rainwater does not run off too quickly. This applies especially to mountain forests, as their natural retention capacities allow the regulation of water resources in river basins. Deforestation of these areas and consequent soil erosion or soil drought must therefore be prevented.

Look after the urban vegetation!

Apart from the obvious aesthetic reasons, trees have a very practical function – they lower the temperature, create cool, shady places for protection from the sun, and absorb many pollutants such as NO, PM, SO2, O3 and greenhouse gases, including CO2. The leaves of trees act as filters: through a process of gas exchange, they absorb the air together with dust and chemical compounds, and they do so extremely effectively: dust in urban spaces can be reduced by up to 75%! Trees produce vital oxygen and contribute to reducing greenhouse gases.

Fot. by Pixabay

However, the most important – and most difficult – task is to retain water, increase retention and prevent the soil from drying out. If we do not take care of the drainage system, there is a risk of sewage failure and periodic flooding. In urban conditions, all vegetation has a beneficial effect on retention phenomena. Unfortunately, as a result of accelerated surface run-off and lowered groundwater table, maintaining green areas and parks in the city is becoming increasingly difficult and expensive. If nothing is done, trees dry out and green areas in cities gradually disappear as a result of these phenomena and urbanisation. Trees are cut down and replaced by shopping centres or supermarkets, which, without ensuring retention, is an example of anthropopression, i.e. the negative impact of human activity on the natural environment.

An important element for the maintenance of green areas in cities may be the use of rainwater and snowmelt collected in multi-functional tanks for the alimentation of green areas, implemented in a cyclic “smart way”. The city should become like a sponge – naturally absorbing rainwater the moment it appears and giving it back later for various purposes for the benefit of vegetation and people.

HYDROZONE retention tanks are one of these smart solutions that are ideal for use in tight urban environments thanks to their compact, modular design. The use of pre-treatment systems offers a wide range of possibilities not only for retention, but also for the use of the stored water. This has a significant impact on stopping urban drying out, i.e. reducing surface water run-off in order to protect and restore water resources.

Rainwater and responsible water management in cities is not only a way to deal with increasingly scarce water resources and an antidote to torrential downpours and flooding. It is also a way to increase the comfort of residents and a key to improving quality of life in cities. Today, we would like to present you with 3 inspiring examples from around the world that should be a signpost for local authorities everywhere.

Why use rainwater?

The world is urbanising at an unprecedented rate. By 2050, the UN estimates that nearly 70% of the world’s population will live in urban areas. While urbanisation has brought us significant benefits, it has also had a detrimental impact on the ecosystem.

This is why modern agglomerations are more and more boldly turning to unusual solutions in the field of rainwater harvesting and transforming concrete deserts into green oases. And all this so that the inhabitants can not only live and work, but also relax in comfortable conditions.

Forest town of Tengah in Singapore

The world leader in urban greening is undoubtedly Singapore. Designers here are increasingly turning to so-called nature-based solutions that effectively mitigate the negative effects of climate change.

A huge futuristic housing project, dubbed by urban planners “Forest Town”, is being built in Tengah, located in the country’s western region and covering an area of 700 hectares. The project’s designers are working on the concept of a smart, sustainable metropolis.

The first housing development to be built within Forest Town was the Plantation District, surrounded by the multi-level Forest Fringe oasis. The district uses, among other things, an urban water harvesting system that aggregates rainwater for irrigation. An automated waste elimination system is also in operation here, which uses high velocity generated by air suction to transport household waste.
In addition to the Plantation District, other unique residential neighbourhoods such as Park, Garden, Brickland and Forest Hill are being developed in parallel.

Willow School in New Jersey

This unique school is located on a 34-hectare plot of land near the centre of Gladstone. The proximity of countryside, beautiful meadows and butterfly gardens are only a part of this unusual project, which aims not only at traditional teaching, but also at shaping a responsible and pro-ecological attitude in the youngest children.

Rainwater is used here, among other things, for flushing toilets and maintaining the surrounding planting, and waste is treated in the most environmentally friendly way possible. Sixty thousand types of grass and perennials have been planted on the school grounds, partly to reduce water consumption, but also to reduce the need to mow and fertilise the area.

Rainwater is collected in a large underground storage tank and then purified and stored in a 2274-litre tank in the basement. After purification, the water is further treated with ozone, so that it looks like pure drinking water. Another tanker with a capacity of 189,500 litres was installed in the new arts building. The school’s water system is constantly monitored, so students can keep track of how much water is actually reused. This state-of-the-art facility is an active learning centre where sustainability is a key element in the children’s relationship with the world of nature.

Green roofs at O’Hare Airport

Chicago’s O’Hare Airport is one of the largest of its kind in the world, with nearly 80 million passengers a year. It is a huge area with impermeable surfaces, which not only increases the energy consumption for air conditioning of airport buildings, but also raises the temperature and increases the so-called urban heat island effect.

The Chicago Department of Aviation therefore decided to create a green roof system and planted vegetation on 12 airport facilities, including the light control centre, car parks, car rental spaces and even the air traffic control tower, a first of its kind in the world.

The design makes it possible to retain 70-90% of rainwater in summer and 25-40% in winter. Vegetation on the roofs also improves thermal insulation, thus reducing heating costs in winter and cooling costs in summer. In addition, vegetation on the roofs absorbs sound waves produced by the aeroplanes. Just a 2.5 cm layer of vegetation on the roof can reduce the noise level entering the building by around 40 decibels!
The project is part of a new vision for the entire city, in which green roofs will be used on a much larger scale. We would also like to encourage such an approach to Polish local governments, declaring at the same time our full readiness to support them in their pro-ecological activities 🙂