PES Process Description of Sequencing Batch Reactor System
SCREENING
Screening Pit (SP) for the first treatment step. A Bar Screen is installed in the Screening Pit to remove large solids such as metals, glass, wood and rags that may clog the process equipment downstream. The Bar Screen is provided with a manual rake arm for small treatment plants, and is upgraded to a fully automatic motorized model in large treatment plants. For the motorized model, the solids are continuously removed from the screen by the motorized rake arm and deposited in a solids compartment for offsite disposal.
EQUALIZATION TANK
As effluent discharge is always non-consistent in most cases, it is necessary to provide for a buffer tank to equalize this inconsistency. The Equalization Tank (EQT) is used to stabilize the variations in flow and effluent characteristics. This is achieved by providing sufficient retention time in the tank, and installing a mixing system to ensure uniform effluent quality at a predetermined flow volume. A coarse bubble diffuser grid is installed in the tank to provide air mixing. Air is supplied by an external air blower connected to the diffuser grid. The tank is also installed with submersible pumps with level switches to regulate the flow going into the next treatment step. Biodegradable solids are cut by the cutter blade impeller of the submersible pump when it is operating, thereby facilitating biological degradation of these solids further downstream.
SEQUENCING BATCH REACTOR
The Sequencing Batch Reactor (SBR) is an activated sludge process designed to operate under non-steady state conditions. An SBR operates in a true batch mode with aeration and sludge settlement both occurring in the same tank.SBRs produce sludge with good settling properties providing the influent wastewater is admitted into the aeration in a controlled manner. Controls range from a simplified float and timer based system with a PLC.
Aerated Fill
Mixed liquor is drawn through the manifold, mixed with the influent flow in the motive liquid pump, and discharged, as motive liquid, to the aerator. This initiates the feast period. Feast is when the microorganisms have been in contact with the substrate and a large amount of oxygen is provided to facilitate the substrate consumption. Nitrification and denitrification occurs at the beginning of this stage. This period ends when the tank is either full or when a maximum time for filling is reached.
React
During this period aeration continues until complete biodegradation of BOD and nitrogen is achieved. After the substrate is consumed famine stage starts. During this stage some microorganisms will die because of the lack of food and will help reduce the volume of the settling sludge. The length of the aeration period determines the degree of BOD consumption.
Settle.
Aeration is discontinued at this stage and solids separation takes place leaving clear, treated effluent above the sludge blanket. During this clarifying period no liquids should enter or leave the tank to avoid turbulence in the supernatant.
Decant
This period is characterized by the withdrawal of treated effluent from approximately two feet below the surface of the mixed liquor by the fixed solids excluding decanter. This removal must be done without disturbing the settled sludge.
Idle
The time in this stage can be used to waste sludge or perform backwashing of the jet aerator. The wasted sludge is pumped to an anaerobic digester to reduce the volume of the sludge to be discarded. The frequency of sludge wasting ranges between once each cycle to once every two to three months depending upon system design.
CHLORINE CONTACT CHAMBER
Biologically-treated effluent shall then flow into the Chlorine Contact Chamber, wherein liquid chlorine is dosed inline to destroy pathogens in the effluent prior to discharge or reuse. The disinfected effluent maybe recycled as gray water for non-potable uses such as landscape irrigation and toilet flushing after installing a simple tertiary filtration system.
AEROBIC SLUDGE DIGESTER
Waste sludge is drained into the Aerobic Sludge Digester for further stabilization and volume reduction. Diffused air is supplied to the tank to provide oxygen for the metabolism and growth of resident microorganisms tasked with digesting the sludge.
Digested sludge may then be siphoned off by third party contractor for disposal offsite, or it maybe dewatered mechanically in a Filter Press Sludge Dewatering System. The sludge is dosed with polymer flocculant and passes through an inline static mixer to ensure homogenous mixing. It then flows to the Filter Press, wherein filter plates are filled up with the sludge slurry and pressed using a hydraulic pump. Filtrate are drained off and returned to the Equalization Tank for treatment. The filter plates are then separated to allow the pressed sludge cake to drop to the filter cake trough. Solids content in the sludge is increased to 30% after pressing, allowing the sludge cake to be placed in plastic bags and disposed offsite or mixed with soil as soil conditioner.
BIO-AUGMENTATION TREATMENT
A comprehensive wastewater treatment program aimed to enhance wastewater treatment parameters and reduce organic loading prior to its final treatment in a wastewater treatment facility which covers program from bacteria seeding for organic digestion to dosing of enzymes serving as catalyst in the biological treatment process. The design of this biological treatment system requires an understanding of the biological principles, kinetics of metabolism, principles of mass balance, and operations necessary to control the environment during the process.
BACTERIA SEEDING
The treatment starts by seeding the type of bacteria culture fit in the wastewater to be treated. Bacteria cultures are seeded in holding tanks such as grease traps, grease interceptors, lift stations and sump pits to achieve the required retention time efficient for the bacteria culture to reach the optimum condition and environment to multiply and biodegrade the incoming organic waste.
ENZYMES - THE CATALYST
The treatment also involves dosing of the required enzymes on the determined dosage points where bacteria cultures are seeded. These enzymes serve as catalysts in the biological process allowing the organic digestion to undertake at a faster rate. With the aid of enzymes, treatment of wastewater requires less retention time resulting to accommodation of a larger volume of wastewater to be treated by the wastewater treatment facility.
WATER SOFTENERS FOR COMMERCIAL AND INDUSTRIAL APPLICATIONS
All water supplies contain some amount of calcium and magnesium, commonly referred to as hardness. Hard water is undesirable for most commercial and industrial uses because of its tendency to form mineral scale, soap scum and chemical sludges. Water softeners utilize ion exchange resin to exchange the calcium, magnesium and other scale forming mineral scale, the process is referred to as water softening.
PHILGEN’s Water Softeners are commonly used in commercial and industrial applications to avoid scale formation, increase the efficiency of soaps and detergent and for chemical processing requirements. Typical applications include boilers, humidifiers, reverse osmosis feed water pretreatment, water heaters, cooling towers, car washers, laundries, hospitals, hotels, apartment complexes, resorts, beverage bottlers, plating shops, manufacturing plants and chemical processing industries.
PHILGEN’s Water Softeners are designed to provide years of trouble free service in demanding industrial and commercial applications. Fiberglass resin or mild steel epoxy coated resin tank are used for corrosion resistance and long life. High capacity ion exchange resin provides superior efficiency with minimal salt consumption. Cast iron diaphragm valves are included for reliability and corrosion resistance. Automatic or manual regeneration is available.
DESIGN FEATURES:
¨ Premium quality ion exchange resin provides exceptional capacity and hardness removal with excellent resin life. Resin meets FDA regulations and is approved by the US Department of Agriculture as well as BFAD. Epoxy coated mild steel tanks ASTM A36 for long-term durability, with an option for fiberglass composite tanks for corrosion resistance.
¨ Individual diaphragm or multi-port valves – flexible choices for automatic regeneration based on timer of flow meter.
¨ PVC flow meters – the meter initiates regeneration based on actual water use to reduce consumption (optional).
¨ Twin alternating systems – provide an uninterrupted supply of soft water. Series of softeners can be furnished as single, twin or triple systems with wide variety of alternator systems. Polyethylene brine tank with salt platform – eliminates corrosion and minimizes cleaning requirements.
¨ High flow distributors – two grades of gravel are combined with high flow distribution with low- pressure drop.
