Biofilms act to increase microbial population density in flow through systems. In attached growth, surface biofilms prevent hydraulic washout and promote more efficient pollution removal than seen in lagoons or ponds.
Can biofilms be used as support media for aerobic wastewater treatment?
This study investigates the microbial community composition, in the biofilms grown on two different support media in fixed biofilm reactors for aerobic wastewater treatment, using next generation… Expand
What are biofilms and why are they important?
Biofilms are important in water and wastewater treatment systems. Biofilms are aggregates of microorganisms suspended in a matrix of extracellular polymeric substances attached to a surface.
What are the biological wastewater treatment systems?
Biological wastewater treatment systems play an important role in improving water quality and human health. This chapter thus briefly discusses different biological methods, specially biofilm technologies, the development of biofilms on different filter media, factors affecting their development as well as their structure and function.
What are aerobic biological processes in wastewater?
Aerobic Biological Processes. Are those where sufficed amount of dissolved oxygen is required into the wastewater to sustain aerobic action, as one of the major polluting effects of wastewater on streams results form the depletion of dissolved oxygen by the action of aerobic organisms in degrading the organic content of the waste.
Why is biofilm formation important?
Biofilm formation is an important survival strategy that bacteria utilize in natural and human-made niches. The detection of adherence of pathogenic bacteria on medical surfaces is necessary to identify and prevent systemic infections related to biofilm-forming bacteria.
What is the main purpose of the secondary waste water treatment process?
Secondary treatment is the removal of biodegradable organic matter (in solution or suspension) from sewage or similar kinds of wastewater. The aim is to achieve a certain degree of effluent quality in a sewage treatment plant suitable for the intended disposal or reuse option.
What is the role of bacteria in secondary treatment of sewage?
Secondary wastewater treatment processes use microorganisms to biologically remove contaminants from wastewater. Secondary biological processes can be aerobic or anaerobic, each process utilizing a different type of bacterial community.
Why are biofilms environmentally important?
Biofilms can harbor human infectious agents in the environment, but they also can promote remediation of contaminated groundwater and soils. They assist in metals mining and they play an important natural role recycling matter on Earth.
Why secondary treatment is important?
Secondary treatment removes the soluble organic matter that escapes primary treatment. It also removes more of the suspended solids. Removal is usually accomplished by biological processes in which microbes consume the organic impurities as food, converting them into carbon dioxide, water, and energy…
What is secondary treatment in wastewater treatment?
Secondary treatment involves the removal of biodegradable organic matter (BOD) and suspended solids (TSS) through the processes of aeration and filtration. Secondary treatment is typically characterized as producing a treated wastewater effluent with a BOD of 25 mg/L or less and TSS of 30 mg/L or less.
How anaerobic bacteria are beneficial in secondary sewage treatment?
Anaerobic bacteria obtain oxygen from their food source. As anaerobic bacteria break down sludge, they produce methane gas. This methane gas can be used as an alternative energy source, called biogas, to fuel the wastewater treatment process.
Why is secondary treatment a biological process?
Secondary treatment removes the dissolved organic matter by the use of biological agents and hence, known as biological treatment. This is achieved by microbes which can consume and degrade the organic matter converting it to carbon dioxide, water, and energy for their own growth and reproduction.
What is the purpose of secondary wastewater treatment quizlet?
The purpose of secondary treatment is to remove the suspended solids that did not settle out in the primary tanks and the dissolved BOD that is unaffected by physical treatment.
Why are biofilms important in human health and environmental processes?
Biofilms show an increased survival and resistance to environmental and chemical stressors (e.g., antibiotics) mainly, but not only, by the protection conferred by the extracellular polysaccharide matrix (Mah and O'Toole, 2001; Stewart and Costerton, 2001; Donlan, 2002; Donlan and Costerton, 2002; Stewart, 2002; Hall- ...
What is water biofilm?
A biofilm is a collection of organic and inorganic, living and dead material collected on a surface. It may be a complete film or, more commonly in water systems, small patches on pipe surfaces. Biofilms in drinking water pipe networks can be responsible for a wide range of water quality and operational problems.
How do biofilms contribute to freshwater marine ecosystems?
Biofilms in aquatic ecosystems colonize various surfaces (sand, rocks, leaves) and play a key role in the environment. Aquatic biofilms supply energy and organic matter to the food chain, they are important in recycling organic matter and contribute to water quality.
What is IFAS in wastewater treatment?
In this study, a laboratory-scale continuous-flow, mixed-growth biological treatment process, based on the integrated fixed-film activated sludge (IFAS) process, was configured using granular activated carbon as the attached-growth media. With potential to degrade target organics, the application of this process for treating the petrochemical industry wastewater may provide a flexible, more efficient, and inexpensive replacement for the activated sludge and other biological treatment processes. The laboratory-scale IFAS configuration was experimented to evaluate the process ability to enhance the biodegradation process utilizing both suspended growth and attached growth, to evaluate its ability to remove nitrogen and phosphorous, and to identify conditions of predominance of attached versus suspended growth. Ratios of attached to suspended growth reached 3 at steady-state conditions; the laboratory-scale flow-through column reached a steady-state operation in 1–2 h, promising smaller tank volumes on a large-scale application. The organics’ removal rates were found to be sensitive to higher initial concentrations and higher hydraulic loading within the range tested in this work. However, nitrogen and phosphorous removal rates were low, and it was mainly attributed to the low total phosphorous-to-chemical oxygen demand ratio representing the bottleneck for upscaling this process.
Why are biofilms important?
Biofilms are important in water and wastewater treatment systems. Biofilms are aggregates of microorganisms suspended in a matrix of extracellular polymeric substances attached to a surface. Their resistance to toxic shocks and retention of slow-growing microorganisms make biofilms advantageous wastewater treatment strategies, achieving efficient removal of a variety of contaminants. Conversely, biofilm mass transfer resistance and predation protection allow them to persist in water distribution systems and other treatment infrastructure where they corrode pipes, reduce pressure head, and allow pathogen persistence. This chapter outlines fundamental biofilm processes, highlights the benefits of biofilm treatment processes, and describes strategies for biofilm control.
What is the oxidation of ammonia to nitrate?
This is achieved by oxidation of most of the ammonia to nitrate during treatment (nitrification ). 2. Nitrification: Means the oxidation of ammonia to nitrate. Nitrification is possible with aerobic biological processes.
What is the main objective of secondary treatment?
The main objective of secondary treatment: To remove most of the fine suspended and dissolved degradable organic matter that remains after primary treatment, so that the effluent may be rendered suitable for discharge. Conventional secondary treatment can reduce the BOD's to below 20mg/l and Suspended Solids to below 30mg/l which is acceptable in ...
What is the material removed from wastewater?
Organic material and nutrients are removed from wastewater flowing past attached growth also known as biofilm. Packing materials used in attached growth processes include rock, gravel, slag, sand, redwood and wide range of plastic and other synthetic materials.
When was the tricking filter invented?
The first tricking filter was placed in operation in England in 1893. the concept of a tricking filter was grew form the of contact frets which were water tight basins filled with broken stones. The limitation the contact filters included a relatively.
Is dissolved oxygen required in wastewater?
Are those where sufficed amount of dissolved oxygen is required into the wastewater to sustain aerobic action, as one of the major polluting effects of wastewater on streams results form the depletion of dissolved oxygen by the action of aerobic organisms in degrading the organic content of the waste. Practical aerobic biological treatment ...
Aerobic Processes
Aerobic secondary treatment of wastewater occurs when various types of electron acceptors are present in the medium then the bacterial cells will utilize the one that produces the highest quantity of energy. Thus aerobic processes will utilize oxygen first.
Anoxic Processes
If the nitrates are present then the microorganisms which are capable of utilizing nitrogen will prevail. during respiration, they will convert nitrate to nitrogen gas (Denitrification) and the processes are collectively called anoxic processes.
Anaerobic Processes
When nitrates are consumed then anaerobic processes start to prevail and other nutrients such as sulfates are utilized. During this process, the sulfates will be converted to sulfites and Carbon-d i-oxide to methane.
Suspended Growth Process
In this growth process, the microorganism which is responsible for the conversion of waste organic matter is maintained into suspension of the liquid phase. Aerobic suspended growth processes include Activated Sludge Processes, Aerated Lagoons, and Sequential Batch Reactors.
Attached Growth Processes
In attached growth processes the microorganisms are attached to the surfaces (such as stones, inert materials) or are self immobilized on flocs or granules in the system. Aerobic Attached Growth Processes include Trickling Filters, Roughing Filters, Rotating Biological Contractors, and Packed Bed Reactors.
What is activated sludge?
The activated sludge process (ASP) is an aerobic biological wastewater treatment process that uses microorganisms, including bacteria, fungi, and protozoa, to speed up decomposition of organic matter requiring oxygen for treatment.
What is the only thing to be provided for the respiration of aerobic organisms?
The organic solids present in the wastewater serve as food for the aerobic microorganisms. The only thing to be provided is the DO , which is essential for the respiration of the aerobic organisms.
What is suspended growth?
In suspended growth systems the microorganisms responsible for treatment are maintained in liquid suspension by appropriate mixing methods. Typically, suspended growth systems require smaller footprints than fixed film systems for an equivalent capacity. There are a number of biological processes. The most common is activated sludge process in which microbes, also known as biomass, are allowed to feed on organic matter in the wastewater and remain in suspension. The make-up and dynamics of the microbial population is a function of how the ASP is operated.
What are the end products of anaerobic and aerobic processes?
Under aerobic conditions, if completely oxidized, organic matter is transformed into non-hazardous products. But an anaerobic process can produce methane (CH 4 ), which is explosive, and ammonia (NH 3) and hydrogen sulfide (H 2 S), which are toxic.
What are the two types of biological processes?
TYPES OF BIOLOGICAL PROCESSES. There are two types of biological treatment process; aerobic and anaerobic. Aerobic process means that oxygen is present for the microbes for respiration. Anaerobic process means that the process proceeds in the absence of DO.
What do aerobic bacteria use for respiration?
Aerobic bacteria use dissolved oxygen (DO) from the water bodies for their respiration. They oxidize organic matter under aerobic conditions. The end products of the decomposition are water, CO 2 and Cell tissues. Anaerobic bacteria use oxygen derived from chemical substances for their respiration.
What is the purpose of sewage treatment?
The purpose of the sewage treatment is to remove the solids present in the sewage. ROLE OF MICROORGANISMS. Microorganisms are unicellular microscopic living things. They multiply by binary division of cells within 10 to 20 minutes. They require oxygen for their respiration.