WASTE WATER TREATMENT TECHNOLOGY:

PHOTOBIOREACTORBy:Norezatul Shahirah bt Ahmad Zamanhuri

PHOTOBIOREACTOR• A photobioreactor is a algae bioreactor that utilizes a light

source to cultivate phototropic microorganisms.• These organisms use photosynthesis to generate biomass from

light and carbon dioxide.• Within the artificial environment of a photobioreactor, specific

conditions are carefully controlled for respective species.• Thus, a photobioreactor allows much higher growth rates and

purity levels than anywhere in nature or habitats similar to nature.• Hypothetically, phototropic biomass could be derived from

nutrient-rich wastewater and flue gas carbon dioxide in a photobioreactor.

system

Closed system

Open system

OPEN SYSTEM• The first approach for the controlled production of phototrophic organisms

was and still is a natural open pond or artificial raceway pond. • Therein, the culture suspension, which contains all necessary nutrients and

carbon dioxide, is pumped around in a cycle, being directly illuminated from sunlight via the liquid’s surface.

• This construction principle is the simplest way of production for phototrophic organisms. But due to their depth (up to 0.3 m) and the related reduced average light supply, open systems only reach limited areal productivity rates.

• In addition, the consumption of energy is relatively high, as high amounts of water containing low product concentration have to be processed.

• Open space is expensive in areas with a dense population, while water is rare in others.

• Using open technologies causes high losses of water due to evaporation into the atmosphere.

OPEN SYSTEM

CLOSED SYSTEM• Since the 1950s several approaches have been conducted to develop

closed systems, which theoretically provide higher cell densities of phototrophic organisms and therefore a lower demand of water to be pumped than open systems.

• In addition, closed construction avoids system-related water losses and the risk of contamination through landing water birds or dust is minimized.

• All modern photobioreactors have tried to balance between a thin layer of culture suspension, optimized light application, low pumping energy consumption, capital expenditure and microbial purity.

• Many different systems have been tested, but only a few approaches were able to perform at an industrial scale.

• Example of the closed system of photobioreactor which are Redesigned laboratory fermenters, Tubular photobioreactors, Christmas tree photobioreactor, and Horizontal photobioreactor.

CLOSED SYSTEM

• decomposition of organic matter

by aerobic bacteria takes place. • To intensify the process of

cleaning, a pool filled with plastic filler with a large surface area that is filled with aerobic bacteria.

PROCESS

• Then the sewage get into the photo-bioreactor with phytoplankton .

• Under the influence of light and nutrients, the amount of biomass of phytoplankton in a photo-bioreactor increases.

• Then absorption of carbon dioxide and release of oxygen takes place.

• Removal of phytoplankton biomass from the water can be carried out by separators and filters .

• Purified waste water goes through the fish and household pool used for bioindication of water quality.

• Since fish can bioaccumulate toxic substances, then analysing the contents of their internal organs may evaluate the integral level of toxicity of wastewater over a period of time.

ADVANTAGES

• Prevent or minimize contamination• Offer better control over existing conditions (pH, light, carbon dioxide,

temperature).• Prevent water evaporation,• Lower carbon dioxide losses due to out gassing,• Permit higher cell concentrations.• Allow you to grow algae in any climate

DISADVANTAGES• Cost• Size and scope• Technical expertise

THANK YOU