Dutchland offers clients a unique combination of engineering and process design, operations expertise and control systems implementation to allow for efficient execution of all wastewater projects. Our multi-disciplinary design team partners with each customer to develop tailored solutions for their unique wastewater needs. Plants are designed to meet various limits, including: pretreatment, secondary treatment, tertiary treatment, and biological nutrient removal. Additionally, Dutchland’s custom solutions for on-site treatment are contained in precast post-tensioned tanks which provide superior material benefits while requiring the lowest maintenance.
Dutchland Inc. employs a treatment process known as extended aeration. Wastewater is processed as it passes through a series of progressive treatment stages. Incoming sewage is first passed through a pretreatment device such as a bar screen or grinder. Bar screens screen incoming waste. Grinders grind the sewage before passing it to equalization. In the equalization tanks, flows and loads are equalized so the process can run near steady state.
The next step in the treatment process is aeration. Influent sewage enters the aeration chamber where it is thoroughly mixed and aerated with large volumes of air. Aerobic bacteria present in the aeration chamber use the air to convert the sewage to stabilized liquids and gases. To obtain complete treatment in approximately 24 hours, it is necessary to provide just the right environment for the bacteria. This is accomplished by the use of Dutchland Inc.'s custom aeration systems with fine dissolved oxygen control. The aeration blowers can be installed on variable frequency drives and controlled by dissolved oxygen probes. Stimulated by the abundant supply of oxygen the bacteria multiply rapidly and are thoroughly mixed with the tank contents to insure complete oxidation of all organic matter.
After approximately 24 hours in the aeration tank liquid flows into settling/clarification where separation of the solids and liquid occurs. In this phase there is no mixing; the liquids are kept perfectly still so suspended particles can settle and be recycled back to aeration to keep the bacteria population alive for continued treatment. This process of removing activated sludge and suspended particles from the liquid leaves a clear, highly treated water at the top of the chamber for discharge from the system. Following discharge from the clarifiers, effluent is disinfected by chlorine or ultraviolet disinfection.
For tertiary treatment a dual media sand filter is added after clarification. This tertiary treatment step allows the wastewater to be treated even further depending on effluent requirements.
The BIO-D Process utilized Modified Ludzaek-Ettinger (MLE) incorporates dual environments of both oxic (aerated) and anoxic (non-aerated, mixed) conditions in separate stages of the plant. Nitrification is accomplished first, followed by denitrification. Nitrification occurs in the aeration tanks of the BIO-D process. A recirculation system is implemented to pump the nitrate-rich wastewater from aeration to the anoxic zone at the head of the plant. The anoxic zone receives all of the energy rich BOD from the influent wastewater as well as the recycled nitrate rich contents from the aeration tanks. The biological culture within the anoxic zone utilizes a portion of the BOD as a carbon food source, and utilizes the nitrates as a source of oxygen, as no oxygen is added in this zone. The nitrates are converted to harmless nitrogen in the process. Mixers provided in the anoxic zone provide the necessary suspension and mixing of the wastewater and facilitate the release of the nitrogen gas bound within the wastewater to the atmosphere.
The extended aeration process is generally capable of reducing Biological Oxygen Demand and Total Suspended Solids to 20 mg/l. With the use of a tertiary filter the BOD and TSS can consistently be removed to 10 mg/l. Ammonia nitrogen levels are consistently treated to less than 5.0 mg/l.
The recycle rate of wastewater from the aeration zone to the anoxic zone is designed for approximately 400% of the average daily flow. Minimum complete dissolved oxygen levels of at least 2.0 mg/L are maintained in the aeration tanks for complete nitrification to take place. The anoxic tank dissolved oxygen levels are maintained at less than 0.5 for denitrification.
The BIO-D Process is generally capable of reducing the total nitrogen level (NO2 +NO3-N + TKN) to average monthly ranges of 6.0mg/l to 8.0 mg/l, depending on the influent concentration of ammonia nitrogen, temperature, and other factors. In addition, by utilizing a phosphorous precipitation chemical such as alum, phosphorous can generally be reduced to 0.5 mg/l or less. The BIO-D technology facilitates biological phosphorous reduction, therefore less chemicals, such as alum, are required while simultaneously providing a greater level of phosphorous reduction.
The Extended Aeration Process can easily be designed for new and existing facilities. For applications ranging from 5,000 – 65,000 gallons per day, the BIO-D Extended Aeration Process is typically incorporated in a modular package plant. For larger applications, the BIO-D process is typically incorporated in a post-tensioned custom-designed structure.
Retrofitting an existing facility for BNR requirements can be done with little modification to the existing facility. New anoxic tanks are installed or existing tanks are converted in the area of the existing facility. With minor process and mechanical revisions, including the addition of a recycle system, the retrofit can be done quickly and cost-effectively.
The Dutchland Sequencing Batch Reactor uses modular or wall panel precast concrete structures to handle all of the work of a conventional continuous flow treatment system. All processes – biological oxidation, sedimentation, nitrification and denitrification occur in a single tank. Multiple tanks are used in alternating sequence.
Typical effluent quality results of Dutchland's SBR:
Advantages of Choosing the Dutchland SBR:
The Dutchland SBR is the perfect solution for: