Human activity is causing major pollution including the introduction of heavy metals, chemical compounds and nutrient-loaded wastewater into the environment. This is polluting aquatic environments causing a decline in biodiversity and is even polluting groundwater sources. Plants and trees and other living organisms have natural filtering and buffering abilities but these vary by plant and by pollutant. For example, some types of moss have been found to absorb lead and arsenic whilst water mint can remove bacteria such as E.coli and salmonella. Advanced ecologically engineered systems (AEES) have been developed which utilise the natural abilities of living organisms to break down macromolecules and metabolise organic nutrients typically found in wastewater and polluted water bodies. The choice of bioremediation strategy depends upon the nature and characteristics of the environment polluted, the nature of pollutants and the availability of biological agents. Microorganisms and plants work together to decontaminate and depollute water. These can be employed externally and internally if the right environment for plant life is generated. For example, the San Francisco Public Utilities Commission shown in the photograph below has an AEES system installed that can treat up to 5,000 gallons of wastewater each day, saving up to 750,000 gallons of water every year. 

Construction generates nearly 40% of global energy-related carbon dioxide emissions and one-third of the world’s waste. However, there are many solutions revolving around bioconstruction being introduced, or re-introduced, into the market. Cob is an ancient material which mixes sand, clay and fibres to construct walls. This was used as far back as the 13th century in the UK but was gradually replaced with more advanced materials which had proven thermal performance. However, the CobBauge Project, funded by the European Union, aims to provide clear performance and usage data such that it meets the thermal performance requirements of modern buildings regulations, specifically Part A and L. The solution combines two 300mm thick layers: a structural inner-face made from cob and an insulating outer face made from lighter earth. This pilot is hoped to act as inspiration for future construction, moving away from more carbon-intensive materials.

Mycelium is a new construction material but an age-old part of our ecosystems. It is the root network of fungi which decomposes organic material within our soils but can be grown from agricultural wastes. When dried the mycelium becomes inactive and forms a building material resistant to water, mould and fire. Despite its lack of compressive strength, it is lightweight meaning it can be stacked as high as 40ft. Fungi also self-regenerates quickly meaning products have potential for fast manufacturing turnovers. So far only experimental construction has taken place with mycelium bricks such as the Hy-Fi Tower in New York. But Italian firm Mogu is already selling flooring tiles and soundproofing wall panels made from mycelium and British firm BIOHM is working to release the first accredited mycelium-based insulation product.

Straw is another ancient construction material making a revival. Straw-bale construction can either be load-bearing when combined with reinforcement or solely as infill wall panels. With either, the walls are plastered or stuccoed. The compression of the straw limits the quantity of oxygen available for combustion meanwhile the high silica content is believed to impede fire. It’s also inherently resistant to rot but high moisture levels can provide a habitat for fungi therefore leading to decomposition. Therefore, designing for moisture avoidance is key. Bristol-based Modcell harnesses these qualities to produce super-insulated prefabricated panels for both external and internal applications. These meet Passivhaus standards, saving up to 90% on fuel bills, whilst offering a 1 hour fire rating. 

Agriculture and forestry consume over 70% of the world’s freshwater resources, cause dangerous pollution levels and soil erosion, and generate 18.4% of total greenhouse gas emissions. Urban Farming can decrease food miles but land in cities is often expensive, especially since gardens tend to contribute to gentrification and rising rents. Urban soils can be loaded with lead, arsenic and other toxins, requiring remediation or replacement before planting can be done safely. Meanwhile, cramped conditions can limit yields and getting enough water and sunlight can be a concern. Urban agroforestry and community gardens however are growing but haven’t yet been executed on a large scale. China’s Forest City, Luixhou offers an insight into what this could look like with predictions that the city could absorb 10,000 tonnes of CO2 and 57 tons of pollutants whilst producing 900 tonnes of oxygen. The same architects have also been redesigning Shijiazhuang, the city in China with the highest rate of air pollution. These cities so far are focused on increasing biodiversity and reducing net emissions as opposed to food production but as soil contamination improves, food forests could be integrated.