Two-stage biofiltration of sulfides and VOCs from wastewater treatment plants

2000 ◽  
Vol 42 (5-6) ◽  
pp. 411-418 ◽  
Author(s):  
J.S. Devinny ◽  
D.E. Chitwood
Keyword(s):  
Organic Compounds ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Low Ph ◽  
Single Stage ◽  
Two Stage ◽  
Neutral Ph ◽  
Support Medium ◽  
Waste Air ◽  
Air Streams

Hydrogen sulfide and volatile organic compounds are often found together in waste air streams. This combination is difficult to treat by biofiltration because oxidation of the sulfide produces acid, reducing the pH in the biofilter. Rapid declines in pH can inhibit treatment of organic compounds. A two-stage biofilter, with the first stage operated at low pH and an inorganic support medium, and the second operated at neutral pH with an organic support can eliminate the problem. A pilot-scale facility was operated on this principle. Comparisons were made among two-stage treatment, single-stage low pH treatment, and single-stage uncontrolled treatment to determine which of the strategies was most effective. In two-stage treatment the first stage did provide protection for the second, allowing it to operate at neutral pH. Single-stage low pH treatment was effective at removing sulfide and many organic compounds, and may be sufficient for many applications.

The main wastewater treatment plant of Vienna: an example of cost effective wastewater treatment for large cities

2006 ◽  
Vol 54 (10) ◽  
pp. 79-86 ◽  
Author(s):  
G. Wandl ◽  
H. Kroiss ◽  
K. Svardal
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Process Management ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Single Stage ◽  
Volume Index ◽  
Two Stage

Two-stage activated sludge plants succeed in stable treatment efficiency concerning carbon removal and nitrification with far less reactor tank volume than conventional single stage systems. In case of large treatment plants this fact is of great economic relevance. Because of the very small specific volume of these two-stage treatment plants in comparison with low loaded single-stage plants, internal cycles have to be applied to ensure sufficient nitrogen removal. Due to these internal cycles two stage activated sludge plants offer many possibilities in terms of process management which results in new process optimisation procedures as compared to conventional single-stage nutrient removal treatment plants. The proposed extension concept for the Main Treatment Plant of Vienna was validated with pilot plant investigations especially with regard to nitrogen removal where it proved to comply with the legal requirements. The operation of the treatment plant can easily be adapted to changes in temperature and sludge volume index occurring in full scale practice. Sludge retention time and aerobic volume in the second stage are controlled in order to secure sufficient nitrification capacity and to optimise nitrogen removal by means of the variation of the loading conditions for the two stages. The investigations confirmed that the specific two-stage activated sludge concept applied in Vienna is an economically advantageous alternative for large wastewater treatment plants with stringent requirements for nitrification and nutrient removal.

Comparison of single-stage and a two-stage vertical flow constructed wetland systems for different load scenarios

2010 ◽  
Vol 61 (5) ◽  
pp. 1341-1348 ◽  
Author(s):  
Guenter Langergraber ◽  
Alexander Pressl ◽  
Klaus Leroch ◽  
Roland Rohrhofer ◽  
Raimund Haberl
Keyword(s):  
Wastewater Treatment ◽  
Standardized Testing ◽  
Wastewater Treatment Plants ◽  
Single Stage ◽  
Organic Load ◽  
Vertical Flow ◽  
European Standard ◽  
Design Standards ◽  
Two Stage ◽  
Testing Procedures

Constructed wetlands (CWs) are known to be robust wastewater treatment systems and are therefore very suitable for small villages and single households. When nitrification is required, vertical flow (VF) CWs are widely used. This contribution compares the behaviour and treatment efficiencies of a single-stage VF CW and a two-stage VF CW system under varying operating and loading conditions according to standardized testing procedures for small wastewater treatment plants as described in the European standard EN 12566-3. The single-stage VF CW is designed and operated according to the Austrian design standards with an organic load of 20 g COD m−2 d−1 (i.e. 4 m2 per person equivalent (PE)) The two-stage VF CW system is operated with 40 g COD m−2 d−1 (i.e. 2 m2 per PE). During the 48 week testing period the Austrian threshold effluent concentrations have not been exceeded in either system. The two-stage VF CW system showed to be more robust as compared to the single-stage VF CW especially during highly fluctuating loads at low temperatures.

Reduce odor and NH3 emission: condensation of the carbonatation vapors

2017 ◽  
pp. 534-537
Author(s):  
Nico Antens ◽  
Jan L.M. Struijs
Keyword(s):  
Direct Contact ◽  
Waste Heat ◽  
Pilot Scale ◽  
Sugar Production ◽  
Two Stage ◽  
Indirect Contact ◽  
Nh3 Emission ◽  
Emission Limits ◽  
Plant Trials ◽  
Contact Condensation

At beet sugar production, vapors from first and second carbonatation contain a significant amount of odor components, NH3 and waste heat, which are normally directly released into the environment. Due to sustainability motivations, obligations regarding odor nuisance and expected stricter regulations regarding NH3 emission limits, Suiker Unie decided to take measures to reduce emission via the carbonatation vapors. During the 2015 beet campaign, pilot scale plant trials have been performed to investigate the effectiveness of indirect contact and direct contact condensation of these vapors. Based on this experimental work a two-stage gas scrubbing concept was designed: in the first stage main goal is condensing the vapors and reuse the heat of condensation to heat up limed juice, while the actual scrubbing takes place in the second scrubber. This two-stage gas scrubbing installation has been built at the Vierverlaten factory and was started up in the 2016 beet campaign. The background, pilot scale trials, concept of design and achieved reductions in odor and NH3 emission at industrial scale are discussed.

Ammonia removal in a pilot-scale WSP complex in Northeast Brazil

1996 ◽  
Vol 33 (7) ◽  
pp. 165-171 ◽  
Author(s):  
J. Soares ◽  
S. A. Silva ◽  
R. de Oliveira ◽  
A. L. C. Araujo ◽  
D. D. Mara ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Surface Waters ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Ammonia Removal ◽  
Northeast Brazil ◽  
Environmental Legislation ◽  
Aerobic Conditions ◽  
High Degree

Ammonia removal was monitored in a waste stabilisation pond complex comprising ponds of different geometries and depths under two different operational regimes. It was found that a high degree of ammonia removal commenced in the secondary maturation ponds, with the highest removals occurring in the shallowest ponds as a consequence of improved aerobic conditions. The tertiary maturation ponds produced effluents with mean ammonia concentrations of < 5 mg N/l, the maximum permitted recommended by Brazilian environmental legislation for the discharge of effluents of wastewater treatment plants into surface waters. Ammonia removal in the secondary facultative and maturation ponds could be modelled using equations based on the volatilization mechanism proposed by Middlebrooks et al. (1982).

The anaerobic treatment of a ligno-cellulosic substrate offering little natural pH buffering capacity

1998 ◽  
Vol 38 (4-5) ◽  
pp. 29-35 ◽  
Author(s):  
C. J. Banks ◽  
P. N. Humphreys
Keyword(s):  
Ph Control ◽  
Anaerobic Treatment ◽  
Buffering Capacity ◽  
Single Stage ◽  
Stable Operation ◽  
Reactor Performance ◽  
Two Stage ◽  
Ph Buffering ◽  
Stage System ◽  
The Stability

The stability and operational performance of single stage digestion with and without liquor recycle and two stage digestion were assessed using a mixture of paper and wood as the digestion substrate. Attempts to maintain stable digestion in both single stage reactors were unsuccessful due to the inherently low natural buffering capacity exhibited; this resulted in a rapid souring of the reactor due to unbuffered volatile fatty acid (VFA) accumulation. The use of lime to control pH was unsatisfactory due to interference with the carbonate/bicarbonate equilibrium resulting in wide oscillations in the control parameter. The two stage system overcame the pH stability problems allowing stable operation for a period of 200 days without any requirement for pH control; this was attributed to the rapid flushing of VFA from the first stage reactor into the second stage, where efficient conversion to methane was established. Reactor performance was judged to be satisfactory with the breakdown of 53% of influent volatile solids. It was concluded that the reactor configuration of the two stage system offers the potential for the treatment of cellulosic wastes with a sub-optimal carbon to nitrogen ratio for conventional digestion.

scholarly journals A Comparison of Two-Stage and Traditional Co-Composting of Green Waste and Food Waste Amended with Phosphate Rock and Sawdust

2021 ◽  
Vol 13 (3) ◽  
pp. 1109
Author(s):  
Edgar Ricardo Oviedo-Ocaña ◽  
Angélica María Hernández-Gómez ◽  
Marcos Ríos ◽  
Anauribeth Portela ◽  
Viviana Sánchez-Torres ◽  
...  
Keyword(s):  
Organic Matter ◽  
Product Quality ◽  
Food Waste ◽  
Phosphate Rock ◽  
Pilot Scale ◽  
Two Stage ◽  
Green Waste ◽  
Wet Weight ◽  
Two Phases

The composting of green waste (GW) proceeds slowly due to the presence of slowly degradable compounds in that substrate. The introduction of amendments and bulking materials can improve organic matter degradation and end-product quality. However, additional strategies such as two-stage composting, can deal with the slow degradation of green waste. This paper evaluates the effect of two-stage composting on the process and end-product quality of the co-composting of green waste and food waste amended with sawdust and phosphate rock. A pilot-scale study was developed using two treatments (in triplicate each), one being a two-stage composting and the other being a traditional composting. The two treatments used the same mixture (wet weight): 46% green waste, 19% unprocessed food waste, 18% processed food waste, 13% sawdust, and 4% phosphate rock. The traditional composting observed a higher degradation rate of organic matter during the mesophilic and thermophilic phases and observed thermophilic temperatures were maintained for longer periods during these two phases compared to two-stage composting (i.e., six days). Nonetheless, during the cooling and maturation phases, the two treatments had similar behaviors with regard to temperature, pH, and electrical conductivity, and the end-products resulting from both treatments did not statistically differ. Therefore, from this study, it is concluded that other additional complementary strategies must be evaluated to further improve GW composting.

Numerical assessment on the performance of variable area single- and two-stage ejectors: A comparative study

2021 ◽  
pp. 095440892110331
Author(s):  
Anil Kumar ◽  
Virendra Kumar ◽  
PMV Subbarao ◽  
Surendra K Yadav ◽  
Gaurav Singhal
Keyword(s):  
Change Theory ◽  
Single Stage ◽  
Two Stage ◽  
Entrainment Ratio ◽  
Ansys Fluent ◽  
One Dimensional ◽  
Flow Parameters ◽  
Constant Rate ◽  
Numerical Assessment ◽  
The One

The two-stage ejector has been suggested to replace the single-stage ejector geometrical configuration better to utilize the discharge flow’s redundant momentum to induce secondary flow. In this study, the one-dimensional gas dynamic constant rate of momentum change theory has been utilized to model a two-stage ejector along with a single-stage ejector. The proposed theory has been utilized in the computation of geometry and flow parameters of both the ejectors. The commercial computational fluid dynamics tool ANSYS-Fluent 14.0 has been utilized to predict performance and visualize the flow. The performance in terms of entrainment ratio has been compared under on- design and off-design conditions. The result shows that the two-stage ejector configuration has improved (≈57%) entrainment capacity than the single-stage ejector under the on-design condition.

A pilot-scale study of a novel two-stage denitrification filter

2021 ◽  
Vol 39 ◽  
pp. 101873
Author(s):  
Qiming Guo ◽  
Zhihong Yang ◽  
Qun Zhao ◽  
Jing Chen ◽  
Jie Li ◽  
...  
Keyword(s):  
Pilot Scale ◽  
Two Stage
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