Chemical free Nutrient Removal from Wastewater by Valuable Algae Biomass

Highly efficient photobioreactors for sustainable wastewater treatment

Water is one of the most important resources in the world. The global supply will be among the greatest challenges of the future. With the increasing world population, water needs to be spread around more and more people. At the same time, the amount of water used in agriculture and industry has tripled over the last decades. Facing this growing demand, wastewater is gaining importance as an alternative source for water supply. In their world water report 2017, the United Nations even refer to it as resource providing clean water, energy, nutrients and other useful by-products for the reutilization. Therefore, the usage of wastewater preserves human and ecosystem health, food and energy security as well as climate protection.
Industrial filtration and cleaning systems lay the foundation for the utilization of wastewater. One approach to reduce pollutants is using algae and other biological organisms. Microalgae absorb nitrogen in form of nitrate and phosphorus in form of phosphate from the wastewater and clean it by separating the nutrients as biomass. This method allows cleaning municipal, agricultural or industrial wastewaters a lot more efficient than conventional treatment plants do. Another advantage: The biomass separated in this process can be reutilized for example as bioplastics, industrial chemicals, organic agriculture, and biofuels.

ABNR™: Algae in photobioreactors clean wastewater and additionally generate biomass

Clearas Water Recovery is a US company that pursues sustainable water treatment with great commitment. With its patented “Advanced Biological Nutrient Recovery” (ABNR™) process, the company has been offering innovative biological wastewater treatment technology for industrial, municipal and agricultural customers since 2011.
The principle is that ABNR™ technology reliably gains back excess nutrients and other pollutants from wastewaters by using a special flow process involving algae and other existing biological organisms. During the first phase, contaminated wastewater and carbon dioxide (CO2) are mixed with a composition of algae and other existing biological organisms in a mixing vessel. In the second phase, the biodiverse mixture is forwarded for cleaning in a closed photobioreactor, which consists of horizontally arranged SCHOTT glass tubes that lie on top of each other. The greenhouse structure and light sources provide for optimal biological activity and photosynthesis. The algae inside continuously break nitrogen down, biodegradable in symbiosis with bacteria phosphates, carbon dioxide and unwanted pollutants. In this process, pollutants are absorbed by the algae and converted into biomass without generating any new pollutants. In a third separation phase finally, modern micro-filtration separates the mixture into two streams: purified clear water, which can be easily discharged into rivers, lakes and streams, or be reused in plant operations; and a recirculation or recycle stream. The latter leads algae and other microorganisms back into the mixing vessel, from where they undergo the same process again. Excess algae are removed and used as valuable biomass.

Summing it up: in three phases the ABNR™ process significantly reduces levels of multiple constituents – including phosphorus by a factor of 10 and nitrogen by a factor of 3 – and other harmful contaminants in wastewater. The result is clean water, an increase of up to 40% dissolved oxygen and no harmful by-products to dispose of. Even though this is not yet possible, wastewater treatment technology will develop continuously to achieve drinking water quality out of wastewater.

The contribution of SCHOTT

By producing high quality glass tubing, SCHOTT enables Clearas Water Recovery to construct efficient photobioreactors for chemical free wastewater treatment. Due to its products and comprehensive expertise in this sector, SCHOTT is an important partner for the algae industry. The material glass ideally meets the high demands of photobioreactors. This is why SCHOTT produces technically and economically superior glass tubes for their construction.
Compared to plastic, SCHOTT high quality glass tubing offers many advantages: it is highly chemically resistant, durable, and mechanically very strong. In addition, the borosilicate glass tubing DURAN® allows for optimum and sustainable light input for highest growth rates of microalgae. With glass U-bends, manifolds and food-grade couplings SCHOTT provides reliable and long lasting solutions for bio-secure algae cultivation of  many different species.