Potential Focus Areas

Reducing Nutrient Inputs

This includes approaches to reduce wastewater and runoff inputs that add nutrients especially Nitrogen to the Sea of Marmara. In theory, since there is interchange with the Black Sea on the East and the Agean Sea on the west, the spatial scale of the source of the nutrients in the system could be huge, but given that this is due to the lake stratification, it is expected that controlling the nutrients in the watershed immediately associated with Lake Marmara as shown below could be most effective.

Basins

This will require paying attention to:

  • Domestic Wastewater Management (e.g. move to tertiary treatment): About 53% of the wastewater discharged into the Sea of Marmara has undergone preliminary treatment, about 5% has biological treatment, and about 42% undergoes advanced biological treatment. The Ministry has indicated that there is a need to reduce Nitrogen by 40%, requiring all Marmara region provinces to convert to advanced biological treatment supported by enhanced wastewater discharge standards and regulations. Wastewater discharges could also be reduced by reuse of treated wastewater, and this is planned to increase from the current 3.2% to 5% by 2023 and 15% by 2030.

  • Industrial Wastewater Management: As highlighted in the World Bank’s report ‘From Waste to Resource,’ few of the most cited reasons for poor industrial wastewater management are inadequate legislation, enforcement, regulation, and monitoring of industrial discharge in place, meaning excessive pollutants are released into the environment. Where untreated industrial discharge is released directly into receiving water bodies, water quality deteriorates, with numerous economic, social, and environmental implications. Discharge of wastewater

    There is a huge untapped market and business potential for treated wastewater. As shown in the case studies of San Luis Potosi, Cerro Verde, Durban, and Nagpur, the sale of treated water to industry can help cover most or all the operation and maintenance costs, especially where water is scarce or where water tariffs for industry are high. Under those circumstances, the water utility is in a unique competitive position since the treated wastewater is an attractive option or may be the only available source.

  • Agricultural Effluent Management: Nutrients like Nitrogen (associated with water) and Phosphorous (associated with soil) are often due to agricultural runoff from fields especially where fertilizer use is heavy. As in much of the world, fertilizer consumption has risen dramatically in Turkey in recent decades.



Several factors need to be considered as part of a detailed plan for an effluent management system including soil type, distance to waterways, integration of system into existing infrastructure and management strategies such as irrigation management and fertilizer applications and associated institutional capacity building and monitoring. Some kinds of payment for ecosystem services or eco-compensation approaches could also be explored in this regard to incentivize farmers to change behaviour (e.g. related to use of fertilizers or good land management practices).

  • NBS/GreenTech solutions: There could be a range of new Nature Base Solutions (NBS) or Green Infrastructure or GreenTech solutions that are explored as part of the treatment system in addition to traditional wastewater treatment grey infrastructure. These may include systems such as Floating Treatment Wetlands that may reduce the land requirements and provide the “finishing” that is required to reduce nutrient inputs into the Sea, in addition to other ecosystem benefits.

In-Situ Management

  • Mechanical Extraction: About 4,555 m3 of mucilage was collected from 278 locations in the first 12 days of a campaign that began in early June 2021. This can be slow and expensive but can be a useful short-term strategy while longer-gestation investments are being made in the coming years. Disposal of this collected mucilage is also another issue to be systematically addressed.





  • Biological treatment (with “beneficial bacteria”):

A team from Istanbul University has performed a pilot study to clean mucilage off the Marmara Sea's surface using microorganisms that were obtained over 20 years in a mucilage coverage area. After a barrier surrounds the sea snot, the selected bacteria would decompose the sea snot. Next, bacteria were placed on the surface every morning and evening to decompose the mucilage. There was significantly visible removal after the third application where the mucilage did not settle to the seafloor.

Wastewater treatment facilities in the region will be converted into advanced biological treatment centers, to ensure that only treated water enters the Marmara, it is believed by scientists that a reduction by 40% of nitrogen flow in the Marmara could solve the root cause of the sea snot spread, currently 53% of wastewater in the Marmara region goes through primary treatment, while 42% is subject to advanced biological treatment and 5% to biological treatment.

  • Aerators: Aeration has often been used in water systems (from the famous “Thames Bubbler” a century ago in London to other approaches in lakes and reservoirs. It needs to be analyzed in this situation given the stratification and the mucilage problem, and type of bacteria present if and where these could be useful.


  • Ultrasonic Algal Control: Ultrasonic algae control devices create ultrasonic sound waves, creating an ultrasonic pressure in the top layer of the water which acts as a barrier and prevents algae from rising to the surface and absorbing light for photosynthesis. The algae dies while the cell wall remains intact, preventing release of toxins from algae into the water. The algae then will sink to the bottom of the waterbody and degraded by the bacteria present.