What is the rate limiting step in UASB reactor?
The Hydrolysis of retained particles is in general considered as the rate-limiting step of the overall digestion process and is highly influenced by process temperature and solids retention time. When using UASB reactors, the SRT should be long enough to provide methanogenic conditions as illustrated in Table 6.
What is the minimum influent COD load beneficial for the UASB process?
What is the minimum influent COD load beneficial for the process? Explanation: Influents should have concentrations of above 250 mg COD/Lm, as for lower rates, anaerobic digestion is not beneficial. Optimum influent concentrations are above 400 mg COD/Lm and an upper limit is not known. 3.
What is the disadvantages of the UASB biogas reactor?
The UASB reactor can be successfully applied for the anaerobic treatment of wastewater if well-settling biomass with high methanogenic activity is developed….23.7. 1 Upflow anaerobic sludge blanket (UASB) reactor.
| Advantages | Disadvantages |
|---|---|
| Simple reactor construction | Sensitive response to organic shock loads |
What is the minimum pH to be maintained for the UASB process?
between 6.3 and 7.85
Explanation: The pH value needs to be between 6.3 and 7.85 to allow bacteria responsible for anaerobic digestion to grow. The pH value is also important because at high pH- values, ammonia disassociates to NH3 which inhibits the growth of the methane producing bacteria.
What is the working principle of UASB?
UASB uses an anaerobic process whilst forming a blanket of granular sludge which suspends in the tank. Wastewater flows upwards through the blanket and is processed (degraded) by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket with the aid of flocculants.
What is UASB ETP?
The upflow anaerobic sludge blanket reactor (UASB) is a single tank process. Wastewater enters the reactor from the bottom, and flows upward. A suspended sludge blanket filters and treats the wastewater as the wastewater flows through it.
What is the rate limiting step in anaerobic digestion Mcq?
methanogenesis
Explanation: In the case of anaerobic digestion, methanogenesis is the rate limiting step. This results in longer solid retention time. In the case of acid fermentation, hydrolysis is the rate limiting step. 16.
What is the principle of UASB?
In which phase of UASB reactor high concentration of biomass contain?
Generally, during the treatment of UASB reactor, the substrate passes through an expanded sludge bed which containing a high concentration of biomass first. After that, the remaining part of substrate passes through a less dense biomass which named the sludge blanket.
What is the minimum percentage of solids in wastewater?
What is the minimum percentage of solids in wastewater? Explanation: The organic matter consists mainly of proteins, carbohydrates and fats. Between 40 and 65 % of the solids in an average wastewater are suspended.
What is the size of the microbial granules in the UASB?
3.2. The modal sizes (diameter) of the granules of UASB1 and UASB2 were 3–4 and 1–2 mm, respectively (Fig. 3).
What is the rate limiting factor in biogas production?
Anaerobic biogas production is a four-stage microbial process consisting of hydrolysis, acidogenesis, acetogenesis/dehydrogenation, and methanation, of which hydrolysis is considered to be the rate-limiting step (Nguyen et al.
What is the maximum concentration of total solids present in wastewater?
8. What is the maximum concentration of total solids present in wastewater? Explanation: The concentration of total solids present in weak wastewater is 350 mg/ L. The concentration of total solids present in strong wastewater is 1200 mg/ L.
What pH level is maintained for biogas generation?
The results from the experiments showed that pH value around 7.2-7.4 is suitable for biogas production in Bangladesh and the production became maximum at pH level of 7.3.
What is UASB reactor technology?
Up flow anaerobic sludge blanket technology also known as UASB reactor is a form of anaerobic digester which used in wastewater treatment. UASB reactor is a methane-producing digester, which uses an anaerobicprocess and forming a blanket of granular sludge and is processed by the anaerobic microorganisms. 2
What is Upflow Sludge blanket digestion?
Upflow anaerobic sludge blanket digestion. Upflow anaerobic sludge blanket ( UASB) technology, normally referred to as UASB reactor, is a form of anaerobic digester that is used for wastewater treatment . The UASB reactor is a methanogenic (methane-producing) digester that evolved from the anaerobic clarigester.
What is the average load of a UASB?
The average full-scale design loading of the UASB of 682 full-scale plants surveyed was 10 kg COD/m3.d. To reduce the plan area and to reduce the cost of land, GLS separator and influent distribution arrangement etc. the reactor should be as high as possible.
Does UASB technology work for sewage treatment?
This paper highlights some inherent lacunae of UASB technology for sewage treatment based on a set of case studies, effluent data of UASB systems and a long-term monitoring of the performance of pilot plants in Kantapur (India). TARE, V. NEMA, A. (n.y): UASB Technology-expectations and reality.