Temporary sewage treatment plant for a new power station
The Carrington STP is of the packaged type plant design and is based on our high performance modular Eco-SAF biological system comprising of:
|Population Equivalent (PE)||490 Flow / 800 BOD|
|Mean Hydraulic loading||88m3/d|
The Carrington sewage treatment plant is to treat the construction site commercial wastewater to the effluent standard quality as follows:
|BOD (5 day settled)||mg/l||30||95%|
|Ammonia as N||mg/l||10||95%|
Comprising of the following elements:
Primary Settlement/Flow Balancing Tank – Where heavy solids are allowed to settle into the sump of the primary tank as sludge. The sludge is removed periodically along with the lighter floating solids including any oils and grease. The tank is designed to BS 6297 2007 to ensure relevant surface area and rise rates are achieved. A scum board and weir is fitted to allow forward flow of only the decanted liquor. The module also has a flow balancing compartment which combined with the unique flow control system in the Eco-SAF provides equalisation of the incoming flow. This helps to prevent shock loading and provides a stable environment and control of the biomass in the bioreactor cells.
The Eco-SAF module – the essential biological stage where bacterial microorganisms are cultivated and actively consume the suspended organic material found in the decanted liquid from the primary process. The aerated cells are equipped with a fine-bubble aeration system distributing the oxygen that is required to maintain a healthy and stable population of heterotrophic bacteria. Oxygen is supplied to the air diffuser system by side channel Blowers c/w integral inverters that require minimum maintenance.
The module is a series of aerated cells and anoxic zones along with a De-Nitrification cell for enhanced ammonia removal. The aerated and De-Nitrification cells are also furnished with fully submerged bio-film growth media to ensure that the microorganisms have a substantial area for growth and a stable environment. Full floor coverage with the aeration diffusers ensures there is maximum oxygen transfer and there are no ‘unaerated’ dead zones as in circular tank designs.
Final Settlement – Lamella clarifier. Any remaining solids (Humus) are settled out of the biologically treated effluent with the aid of a Lamella pack and returned upstream as enriched activated sludge (RAS) to be absorbed in fresh wastewater. The Lamella pack increases the active area and therefore improves the settling ability of the sludge within a small footprint.
Ultra Violet Disinfection – As additional tertiary treatment a UV system was installed to further treat faecal coliforms.