Solution Cases 1: Municipal Wastewater Solution 200,000M³/d Capacity
Solution Case: Municipal Wastewater
Start Up: October 2016
Capacity: 200,000 m³/d
One of the major concerns regarding municipal wastewater treatment plant discharge is the rising concentration of nutrient compounds, specifically nitrogen and phosphorus. Nitrogen and phosphorus are the primary causes of cultural eutrophication (i.e., nutrient enrichment due to human activities) in surface waters. The most recognizable manifestations of this eutrophication are algal blooms that occur during the summer. Chronic symptoms of over-enrichment include low dissolved oxygen, fish kills, murky water, and depletion of desirable flora and fauna.
Challenges
Challenges faced by existing plants wastewater treatment plants that employ conventional biological treatment processes designed to meet secondary treatment effluent standards typically do not remove total nitrogen(TN) or total phosphorus(TP) to the extent needed to protect receiving waters. However, wastewater treatment facilities are increasingly being required to address this issue by implementing treatment processes that reduce effluent nutrient concentrations to levels that regulators deem sufficient to protect the environment. Implementation usually involves major process modifications to a plant, such as: making a portion of the aeration basin anaerobic or anoxic, which reduces the aerobic volume and limits nitrification capacity. Clarifier solids loading is usually the factor that limits the concentration of biomass available for nitrification, so the common practice is to increase bioreactor volume to increase treatment capacity. This can be very expensive and sometimes impossible if space is limited.
Solution
One cost-effective solution to achieve biological nutrient removal is the BioCell process, developed by BioCell Company. The BioCell process employs the benefits of fixed-film systems into the suspended growth activated sludge process. This hybrid process is referred to as Integrated Fixed-film Activated Sludge (IFAS) technology.
The BioCell IFAS process is typically divided into a series of stages that include anaerobic, anoxic, and aerobic volumes. Within the BioCell IFAS process, media is filled in the aerobic stages and retained by stainless steel wedge-wire screens located at the effluent end of the process stage.
Existing Activated Sludge Plant
Activated Sludge Plant Converted To IFAS
Results
The plant has operated efficiently since the start up. Due to the low water temperature of10℃, an almost full development of the biofilm was noticed in less than a month.
Solution Cases 2: Municipal Wastewater Solution 50,000M³/d Capacity
Solution Case: Municipal Wastewater
Start Up: May 2015
Capacity: 50,000 m³/d
About Integrated Fixed-film Activated Sludge (IFAS) Technology
An integrated fixed-film activated sludge (IFAS) process incorporates the technological benefits of traditional systems of activated sludge with biofilm systems of activated sludge with biofilm systems in a single reactor. The IFAS configuration is conventionally similar to an activated sludge plant that takes advantage of a variety of processes; namely MLE, UCT, or Bardenpho, with biomass carriers fed into predetermined zones within the activated sludge process. Two precise biological populations thus act in combination with MLSS to break down a major proportion of the organic load (BOD) and the biofilm that results in a nitrifying population for the oxidation of the nitrogenous load.
IFAS is employed to update and improve nitrogen removal at plants already in operation. Additionally, IFAS can also be integrated in the design plans for new plants as part of a smaller footprint during the BOD and nitrogen removal processes.
Challenges Faced by Existing Plants
The design capacity of the WWTP is 50,000m3/d, and the A2/O oxidation ditch be applied for the biological treatment process, below are the influent and effluent parameters of the existing plant:
| Project | Unit | Influent | Effluent |
| COD | mg/L | 350 | 60 |
| BOD | mg/L | 160 | 10 |
| NH3-H | mg/L | 30 | 15 |
| TN | mg/L | 40 | 20 |
The Effluent Parameters Requirement of Completed Plant
| Project | Unit | Effluent |
| COD | mg/L | 40 |
| BOD | mg/L | 6 |
| NH3-H | mg/L | 5 |
| TN | mg/L | 15 |
Placing BioCell media into activated sludge basins creates a combination of suspended and attached growth biology that optimizes the benefits of both of these systems. Each individual piece of BioCell media has been specifically designed with a very high surface area-to-volume ratio to support the growth of biofilm. The surface area provided by the BioCell media creates additional active biology above and beyond the limits of the suspended activated sludge system.
This can increase reactor capacity, in terms of organic loading, or support more advanced treatment of the wastewater due to longer sludge age. The additional fixed film biomass does not need to be settled out and returned and therefore does not increase the solids loading to the secondary clarifier, a factor that often limits the treatment capacity of activated sludge systems. IFAS technology addresses the need for increasing activated sludge plant capacity without additional clarifier or aeration basin volume. The fixed biomass also contributes to the ability of the process to respond to organic or hydraulic shock loads and to recover from upsets.
The BioCell IFAS process is the perfect solution for upgrading existing plants to support Biological Nutrient Removal without adding reactor volume. Portions of existing aerobic zones can be partitioned into anaerobic or anoxic zones for advanced BNR treatment and the addition of BioCell media to the remaining aerobic zones increases the Solids Retention Time (SRT) to a level needed for nitrification.
Results
Effluent COD and NH4-N were well removed, and the effluent quality could conforms to owner's permitted criteria.
Solution Cases 3: Municipal Wastewater Solution 20,000M³/d Capacity
Solution Case: Municipal Wastewater
Start Up: May 2016
Capacity: 20,000 m³/d
This is the first large water reuse project in lran, the first project which use the waste water as steel production water source, the whole water supply system of the factory not need to use any fresh water.
We cooperated with DANIELI, and provide the MBBR process package and technology service.
Challenge
This WWT plant design capacity is 860m3/h, it is the municipal waste water, the Inlet and MBBR outlet values as follows:
| Parameter | Unit | Inlet Values | Outlet Values |
| COD | mg/L | 80~250 | ＜50 |
| BOD5 | mg/L | 40~150 | ＜10 |
| NH4-N | mg/L | 0.1~50 | ＜5 |
Solution
The treatment process is MBBR+UF+RO, and provides a new solution for the severe water shortage problem in lran.
The main characteristic of Moving Bed Biological Reactor (MBBR) configurations is that there is no sludge recycle from a secondary clarifier. MBBR is essentially a simple, once-through process, where all of the biological activity takes place on the biomass carriers. MBBR is usually followed by a solids separation system such as a secondary clarifier or DAF, to separate bio-solids produced in the process from the final effluent. The main advantage of MBBR is robust and simple reduction of soluble pollutants (soluble BOD or COD, NH4 +, etc.), with minimal process complexity, utilizing.
There are two sets of parallel operation MBBR tanks, each tank has seven sets aeration pipe, of which from one to six sets are the same, the rest of the final set near the media retention screen be added more areator, to prevent the media pilling up on the screen.
BioCell Media
Media provides two important functions: The protected internal surface area allows the biofilm to attach while supporting either the heterotroph / autotroph bacteria. Second, the millions of pieces of media act as a shearing device on the course air bubble to maximize oxygen transfer.
Aeration Pipe
A stainless steel coarse bubble aeration system is employed to mix the suspended media evenly throughout the reactor while providing the mixing energy required to slough old biofilm from the internal surface area of the media and maintain the dissolved oxygen required to support the biological treatment process.
Media Retention Sereen
Stainless steel wedge wire screens retain the cultivated biofilm / media in a process-designated reactor while allowing the treated wastewater and sloughed biofilm to flow through to the next treatment phase.
Results
The whole project implemented succesfully, to be well received by the general contractor and the owner.
The COD value of the effluent is below 30mg/l, keep a long term and stable run.