Wasterwater Treatment
PMT Ecodisk™
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A well designed and correctly sized bio-disk installations can solve sewage treatment problems for small and medium sized communities. PMT Ecodisks™ have many advantages over other treatment processes:
Operating PrincipalThe wastewater is pumped or flows by gravity to the first chamber of a three chamber primary tank constructed in-situ. Primary sedimentation takes place in the primary tank prior to the clarified wastewater passing over weirs and discharging into the inlet line to the Bio-disk for the secondary treatment phase. In the secondary treatment phase, the biodegradable matter in the wastewater is aerobically digested. The main components of the system are the rotating discs. These circular discs are mounted on a horizontal shaft which is connected by a flexible coupling to a small gear motor. An aerobic bio-film forms on the disc surface which is constantly fed with oxygen as the discs rotate. The film is maintained at a pre-determined thickness by the disc spacing and the rotation speed of the discs which sloughs off excess growth and introduces air into the wastewater. This ensures a high level of dissolved oxygen within the process stream and allows greatly reduced contact time. Since the micro organisms are attached to the disks as a fixed film biomass, it is not possible to wash these out of the plant at times of excess flow. Sludge re-circulation is also not necessary. The sloughed off bio-film is elevated by a lifting wheel with the treated wastewater to a lamella separator. The lamella separator is used for the clarification of the wastewater passing from the biological stage.
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It consists of a sludge tank shaped as a hopper containing parallel plates mounted at an angle of 55º. The large surface area of the plates provide a quasi-laminar flow which enables the heavier particles of sludge to settle on the upper surface of the plates and the clarified water to move upwards along the lower side of the plates and slowly reach the outlet. The sludge slides downwards into the sludge hopper where it settles. The sludge outlet is at the lowest point of the hopper. Settled sludge is periodically pumped from the hopper to the first chamber of the primary sedimentation tank where it consolidates with the primary sludge. This operation is fully automatic and controlled by a time clock. In an Ecodisk™ Filter, the sloughed off bio-film is elevated by a lifting wheel with the treated wastewater to a 2m Hyrotech Drum filter. Prior to discharge, the wastewater passes through a 20 micron polyester screen on which the bio-film is retained. The bio-film is periodically removed by a high pressure spray pump and returned to the first chamber of the primary tank. This operation is fully automatic and controlled by a time clock. Three bucket elevators are attached to the shaft of the Bio-disk unit. One elevator is positioned in a separate chamber at the inlet to the Bio-disk. This elevator is utilised to lift primary clarified effluent from the buffer zone in the primary tank into the first tank of the aerobic zone at a constant rate to buffer flow surges. The optional second bucket elevator is positioned immediately following the biological stage and is designed to re-circulate the flow back to the first section of the three stage primary tank where anoxic conditions occur and denitrification takes place and the third elevator is positioned at the outlet end of the shaft and is used to lift the mixed liquor up into either the lamella separator or the drum filter for clarification. The clarified wastewater passes through an optional tablet chlorinator or UV disinfection system where disinfection takes place prior to discharge or storage. The primary and secondary sludge is digested in the primary sedimentation tank prior to being periodically pumped out for dewatering or off-site disposal.
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Typical Installation
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A well designed and correctly sized bio-disk installations can solve sewage treatment problems for small and medium sized communities. PMT Ecodisks™ have many advantages over other treatment processes:
Operating PrincipalThe wastewater is pumped or flows by gravity to the first chamber of a three chamber primary tank constructed in-situ. Primary sedimentation takes place in the primary tank prior to the clarified wastewater passing over weirs and discharging into the inlet line to the Bio-disk for the secondary treatment phase. In the secondary treatment phase, the biodegradable matter in the wastewater is aerobically digested. The main components of the system are the rotating discs. These circular discs are mounted on a horizontal shaft which is connected by a flexible coupling to a small gear motor. An aerobic bio-film forms on the disc surface which is constantly fed with oxygen as the discs rotate. The film is maintained at a pre-determined thickness by the disc spacing and the rotation speed of the discs which sloughs off excess growth and introduces air into the wastewater. This ensures a high level of dissolved oxygen within the process stream and allows greatly reduced contact time. Since the micro organisms are attached to the disks as a fixed film biomass, it is not possible to wash these out of the plant at times of excess flow. Sludge re-circulation is also not necessary. The sloughed off bio-film is elevated by a lifting wheel with the treated wastewater to a lamella separator. The lamella separator is used for the clarification of the wastewater passing from the biological stage.
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BIOROCK®BIOROCK®, the first compact sewage treatment plant in the world without electricity and moving partsBIOROCK® was established in 1988 and is now an internationally acclaimed and experienced company in (compact) sewage treatment technology. BIOROCK® has their own R & D, manufacturing facilities and worldwide sales & technical support network. The BIOROCK® product range can be used to treat sewage from a single house up to public restaurants, hotels, resorts, schools, shopping malls, lodges and other facilities. The BIOROCK®-S Series is a range of compact packaged sewage treatment plants sized in 5, 10 & 15 person units. If installed in parallel they can also cater for 30, 45, 60 people and larger. BIOROCK®-S Series allow for modular expansion. This allows staged development of a project without the need to install a complete system at a high initial cost. This allows a developer to cater for each stage individually in line with the development budget. The BIOROCK®-S Series units are packaged domestic waste water treatment plants providing a consistent high quality effluent that meets high discharge standards. The biological purification technology requires no electricity and has no moving parts. As a result of this; maintenance and operational costs are minimal and systems are particularly reliable. The units are assembled in durable HDPE tanks with lightweight, low profile, access covers. The plants are supplied as a complete package for simple installation. The BIOROCK® S Series utilises a unique fixed bio-film technology with specific functions to achieve an odour free effluent, suitable for irrigation or re-use. The BIOROCK® S Series system functions as a two stage Sewage Treatment Plant. The raw sewage first enters a Primary tank to provide pre-separation and initial breakdown of organic solids. The sewage then passes through an effluent filter before discharging into the BIOROCK unit itself which incorporates an aerobic filtration process. This later stage of the process is defined by layers of BIOROCK® media. The BIOROCK® media is pre-treated with enzymes in order to achieve rapid start up and to stimulate the growth of the correct bacteria type; these bacteria colonize the media in vast numbers and rapidly digest the organic waste. The treatment philosophy has been developed around a combination of aerobic/anoxic biological degradation and filtration.
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