Tanks

Tender description

Tanks are a critical asset in the water and wastewater treatment process. If tanks develop holes and/or cease to work effectively; the treatment process capacity is reduced and can lead to increased running costs and potential for catastrophic failure of the asset. Thames Water Utilities Ltd wishes to establish a framework agreement for the provision of a range of tanks to be used on their Water and Wastewater sites across their entire region. The agreement has been split into three specific lots, covering 5 main tank types. Applicants are invited to apply for the following lots: Lot 1: Sludeg holding tanks and Digesters, Lot 2: Fuel tanks, Lot 3: Chemical tanks and Salt Saturators. Each lot will be awarded to 1-4 suppliers. Companies may apply for one or more lots. The provision of sludge holding tanks and digesters as below. Glass reinforced steel tanks are generally used in Wastewater Sludge treatment applications, i.e. sludge holding tanks, sludge buffer tanks, picket fence thickeners, primary digesters and secondary digesters. Sludge holding, buffer blending tanks: Provide temporary storage for a type of sludge or blend of sludges, i.e. primary, humus and/or activated sludges. These sludges can be indigenous or imported from other sites. Tanks usually include some form of mixing facility. Primary and secondary digesters: Primary digesters are fixed roof structures where blended sludge is digested for between 12 to 25 days to reduce sludge volume, kill pathogens and generate methane gas. Secondary digesters are the second stage of sludge digestion, providing additional pathogen kill. Both tanks include either mechanical mixing (via a pump impeller) or using gas mixing systems. TW wish to award this Lot to up to 4 suppliers that are capable of supplying all tanks covered within scope of this lot throughout the duration of the contract and inline with TW asset standards. The provision of fuel tanks. Fuel tanks are currently used either for bulk storage in the order of up to 350 000 litres or as day tanks from 500 litres to 100 000 litres. TW store these on their premises to heat and run their premises and standby generators. Compliance with government regulations and TW Asset Standards is vital to ensuring not only safety to people and the environment but also that TW are not fined or prosecuted. TW wish to award this lot to up to 4 suppliers that are capable of supplying all tanks covered within scope of this lot throughout the duration of the contract and inline with TW Asset Standards. The provision of chemical tanks and salt saturators as below. Chemical tanks are contained in kiosk type tank units. The tanks contain chemicals, dosing pumps, level sensors, flow meters etc. required for chemical dosing treatment of water and wastewater. These tanks hold various chemicals, including: • sodium hypochlorite, • sodium bisulphite, • sodium hydroxide, • sulphuric acid, • ferric sulphate, • orthophosphoric acid, • polyaluminium chloride, • softened water. Storage tanks are arranged in pairs, depending on the size of the installation many pairs may be connected in series. In each pair there is a master tank and a slave tank. These tanks may be constructed of Thermoplastics or GRP and may be conventionally bunded or internally bunded. Salt saturators are used on sites where part of the treatment requires softened water. This is generally to prevent the main treatment chemical from precipitating out of solution and blocking dosing pipes. Salt saturators normally have a layer of gravel on the bottom, PDV salt is filled on top of this and a constant head of service water is applied to fill the remainder of the tank. This results in a brine solution discharged from the bottom of the tank to whichever application it is used for. These tanks are normally supplied with dust arrestors, which prevent clouds of powdered salt being emitted during deliveries. TW wish to award this lot to up to 4 suppliers that are capable of supplying all tanks covered within scope of this lot throughout the duration of the contract and inline with TW Asset Standards.