Tanks for wastewater treatment

INFINITANK LOW LOAD ACTIVATED SLUDGE TREATMENT

Material: modular tank for underground installation and separator in linear high-density polyethylene (LLDPE). Fitted with inlet and outlet pipe in PVC, blowers and micropore plate for air distribution.

Application: treatment of domestic wastewater by means of primary sedimentation and anaerobic digestion of sludge in biological tanks and subsequent secondary activated sludge aerobic digestion. Rototec’s treatment plant is sized for an average domestic effluent with  a daily load factor of 200 l/AE  and a daily organic pollution of 60gBOD/AE per person. The inlet concentration is assumed to be of 240 mgBOD/l  and providing a primary treatment of type Imhoff or septic tank upstream of the plant. It is of major importance to separate oils and foams upstream of the activated sludge tank as they could adversely affect the treatment efficiency which accounts up to 90% under regular conditions (percentage of reduction of the organic load as per BOD5).

Use and maintenance: it is advisable to inspect the tank at least once a year and to proceed with any necessary extraction of the excess sludge. These operations are usually performed in combination with the inspection and purge of the primary treatments (oil separator and organic tank). The cleaning will be performed by extracting a part of the excess sludge, removing accumulations on inlet and outlet pipes and cleaning the air diffusers in order to prevent possible clogging. Periodically check the operation of the blowers-compressors.

Carefully follow the “INFINITANK INSTALLATION INSTRUCTIONS” supplied by ROTOTEC.

Infinitank one-piece structure actived sludge Treatment

Material: modular tank for underground installation and sedimentation chamber in linear high-density polyethylene (LLDPE). Fitted with inlet and outlet pipe in PVC, blowers and micropore plates for air distribution. Subdivided in two sections for sludge settling and biological oxidation.

Application:treatment of domestic wastewater by means of primary sedimentation and anaerobic digestion of sludge in biological tanks and subsequent secondary activated sludge aerobic digestion. Rototec’s one-piece structured treatment plant is sized for an average domestic effluent with a daily load factor of 200 l/AE  and a daily organic pollution of 60gBOD/AE per person. It is of major importance to separate oils and foams upstream of the activated sludge tank as they could adversely affect the treatment efficiency which accounts up to 90% under regular conditions (percentage of reduction of the organic load as per BOD5). The treated effluent complies with the emission limits described in Table 3 of Law Decree 152/2006 for discharge into surface water courses.

Use and maintenance: it is advisable to inspect the tank at least once a year and to proceed with any necessary extraction of the sludge which is mainly accumulating in the primary sector but also in the activated sludge chamber. The cleaning will be performed by extracting a part of the excess sludge, removing accumulations on inlet and outlet pipes and cleaning the air diffusers in order to prevent possible clogging. Periodically check the operation of the blowers-compressors.

Carefully follow the “INFINITANK INSTALLATION INSTRUCTIONS” supplied by ROTOTEC.

INFINITANK IMHOFF SEPTIC TANKS

Material: corrugated underground container of modular type and sedimentation chamber in LLDPE with PVC inlet and outlet pipes. Manufactured according to standard UNI-EN 12566-3. The Legislative Decree n°152/2006 goes back to the Interministerial Committee on water protection (supplemento ordinario alla G.U. n. 48 del 21/02/77 par. 4), requiring average volumes of 40 I for the sedimentation chamber and of 100 l for the digestion compartment for underground civil wastewater. In the regional versions of Emilia Romagna and Umbria, the Imhoff tanks are sized according to D.G.R 1053/2003 (Emilia Romagna) and D.G.R. 1171/2007 (Umbria).

Application: purification of civil wastewater through primary sedimentation treatment and smudge biological digestion. This  type  of  treatment  also  allows  the simultaneous removal of 25-30% of the organic content, in terms of BOD5. Imhoff tanks consist of two overlapping and hydraulically communicating compartments. In the upper compartment, the sedimentable solids gravitate to the bottom of the sedimentation chamber, which has a suitable inclination to allow the sludge to pass to the lower compartment where it is digested. This type of plant makes use of the combined actions of a mechanical sedimentation process and a biological treatment of cold anaerobic digestion.

Use and maintenance: an excessive accumulation of putrescible material at the bottom of the tank can cause uncontrolled anaerobic digestion phenomena, leading to an over-production of biogas and the development of malodorous emissions. Furthermore, the reduction in the volume available in the digestion compartment and the excessive production of gas bubbles will cause the settled material to rise, thus causing deterioration in the quality of the treated effluent. The use of the Rototec BIO-ACTIVATOR is highly recommended for rendering the initiation of the biological processes more rapid, thus limiting the number of sludge removal operations and reducing the risk of malodorous emissions. The Imhoff tanks are designed to pro-vide primary sludge storage for a period of 6-8 months of plant operation. When sizing plant for Sensitive Areas, the frequency of sludge emptying operations is reduced to once every 12-14 months. A minimum of 1-2 inspections per year by qualified personnel and eventual emptying operations must be programmed according to the loads fed to the tank. Once the settled sludge has been removed, the internal surfaces of the tank must be cleaned in order to eliminate any material obstructing the effluent inlet and outlet pipes and the outlet of the sedimentation chamber.

Installation: please follow underground installation instructions provided by Rototec.

INFINITANK SEPTIC TANKS

Material:
corrugated modular container in LLDPE with PVC inlet and outlet pipes and PE sedimentation chamber. Manufactured according to standard UNI-EN 12566-3. The Table 3 of Law Decree 152/06 specifies the limits for delivery to public sewers. The sizing proposed make it possible to reach a retention time of 2-3 hours at mean flow rate in the sedimentation compartment, thus enabling the removal of the solid and organic components required by law. The application shall be assessed by the public sewer service operator.

Application:
primary treatment and anaerobic digestion of wastewater coming from residential buildings.

Use and maintenance:
designed to provide primary sludge storage for a minimum period of 4-5 months of plant operation. A minimum of 1-2 inspections per year by qualified personnel and eventual emptying operations must be programmed according to the loads fed to the tank. Once the settled sludge has been removed, the internal surfaces of the tank must be cleaned in order to eliminate any material obstructing the effluent inlet and outlet pipes and the outlet of the sedimentation chamber.

Installation: please follow underground installation instructions provided by Rototec.

IMHOFF BIOLAGICAL TANK

Material:
corrugated/smooth container and sedimentation chamber in one-piece LLDPE with PVC inlet and outlet pipes. Manufactured according to standard UNI-EN 12566-3. The Table 3 of Law Decree 152/06 specifies the limits for delivery to public sewers. The sizing proposed make it possible to reach a retention time of 2-3 hours at mean flow rate in the sedimentation compartment, thus enabling the removal of the solid and organic components required by law. The application shall be assessed by the public sewer service operator.

Application:
primary treatment and anaerobic digestion of wastewater coming from residential buildings.

Use and maintenance:
The Imhoff tanks are designed to provide primary sludge storage for a minimum period of 4-5 months of plant operation. A minimum of 1-2 inspections per year by qualified personnel and eventual emptying operations must be programmed according to the loads fed to the tank. Once the settled sludge has been removed, the internal surfaces of the tank must be cleaned in order to eliminate any material obstructing the effluent inlet and outlet pipes and the outlet of the sedimentation chamber.

Installation: please follow underground installation instructions provided by Rototec.

BIOLOGICAL SEPTIC TANKS

Material:
corrugated/smooth tank in LLDPE, one-piece structure, with PVC inlet and outlet pipes. Manufactured and sized according to standard UNI-EN 12566-1. The Legislative Decree n°152/2006 goes back to the Interministerial Committee on water protection (supplemento ordinario alla G.U. n. 48 del 21/02/77 par. 4), requiring average volumes of 120-150 I/A.E.

Application:
primary treatment of wastewater coming from residential buildings.

Use and maintenance:
an excessive accumulation of putrescible material at the bottom of the tank can cause uncontrolled anaerobic digestion phenomena, leading to an over-production of biogas and the development of malodorous emissions. Furthermore, the reduction in the volume available in the digestion compartment and the excessive production of gas bubbles will cause the settled material to rise, thus causing deterioration in the quality of the treated effluent. For this reason, 1 to 4 inspections per year by qualified personnel and eventual removal of the surface crust and accumulated sludge must be programmed in accordance with the loads fed to the tank. Once the settled sludge has been removed, the internal surfaces of the tank must be cleaned in order to eliminate any material that could obstruct the effluent inlet and outlet pipes.

Installation: please follow underground installation instructions provided by Rototec.

OIL SEPARATORS

Material:
smooth/corrugated tank and sedimentation chamber in LLDPE, one-piece  structure, fitted with PVC inlet and outlet pipes. Designed for gravity separation of solid materials and oil particles up to 150 µm. Sized according to UNI-EN 858-1 and UNI-EN 858-2, class two oil separator. The version with coalescing filter complies with standard UNI-EN 858-1 and UNI-EN 858-2, class one oil separator fitted with removable coalescing filter made of polyurethane sponge, steel and PVC.

Application:
designed for treating surface runoff from uncovered/covered drainage areas with presence of heavy sediments, mineral oils and hydrocarbons and discharge to public sewer. Designed for treating surface runoff from hardstandings with minor presence of heavy sediments, mineral oils and hydrocarbons and discharge to public sewer. In case of uncovered area, the flow rate is calculated considering a rainfall of 20 mm/h and a unit runoff rate.

Use and maintenance:
an excessive accumulation of floating material causes a reduction in the volume available for separation. This risk worsens in the  presence  of  considerable  quantities  of  sedimentable  substances that settle at the bottom of the plant. To prevent the escape  of  solids  and  mineral  oils  that  could  compromise  the quality of the discharged effluent, it advisable to carry out frequent  inspections  and  removal  of  the  accumulated  pollutants every 6-8 months. These operations should be more frequent if the plant receives effluent from vehicle workshops, oil storage areas or vehicle washes. The deposits must be removed by specialised personnel and subjected to the appropriate treatment. As far as maintenance of the coalescing filter oil separators is concerned, in addition to the normal emptying, it is also advisable to remove the sponge support and wash it thoroughly upstream of the plant.

Installation: please follow underground installation instructions provided by Rototec.

WETLAND TREATMENT SYSTEM

Material:
beds in linear high density polyethylene (LLDPE) for horizontal subsurface-flow wetland treatment through PVC connection pipe with rubber gaskets and deflector T, LLPDE level chambers with PVC inlet and outlet and rubber gaskets.

Application:
secondary or tertiary treatment of civil wastewater through horizontal subsurface-flow wetland system.

Use and maintenance:
in order to ensure the good operation of wetland systems, one must guarantee the proper functioning of the primary treatments (grease separator, Imhoff septic tank) and possibly of the secondary treatments installed upstream of the beds, checking deposits of solid material that could obstruct the distribution systems and accumulate in the soil in which the vegetation grows. During the laying operation, the beds should be placed so as to minimize the inflow of rainwater to the treatment system, creating small sidewalls and reducing the runoff, thus facilitating the growth of turf near the beds. Inspections on the level chambers (DD150FT) shall be carried out every three months with removal of weeds that could affect the development of the species selected for the treatment. Together with the purging interventions of the primary and possibly secondary treatment systems, the distribution pipes shall be additionally cleaned with a pressure wash system.

Installation:
please follow the underground installation instructions provided in the manual attached.

AEROBIC/ANAEROBIC PERCOLATING FILTER INFINITANK

Technical characteristics:
A percolating filter is a biological reactor, inside which the micro- organisms that purify the effluent develop on the surface of special bulk fill material (filter media). The uniform distribution of the effluent through the filter guarantees maximum contact between the organic material to purify and the biological film covering the spheres making up the fill material. The spheres of the filter media are manufactured in polypropylene and are designed to provide a large surface area available for bacterial micro-organisms to take root. In particular, the spheres used provide a surface area per unit volume of filter media of 140 m2/m3, much higher than the traditional stone fill material, with voids accounting for over 90% of the volume. This solution minimises the risk of clogging the bed and also guarantees an improved circulation of air through the bed of the aerobic filter. Percolating filters allow good purification performance without any energy overheads, with management costs limited to the occasional cleaning of the plant. The sizing of percolating filters for an average domestic effluent refers to the organic load factor (kgBOD /m3d) with which the filter is fed. This parameter is the ratio between the organic load at the inlet (kgBOD d) and the volume of the filter bed. Rototec filters are designed to operate with medium-low organic load factors (kgBOD /m3d). This guarantees a good margin of safety, with respect to fluctuations in inlet flow, and a limited produc-

Application:
Treatment of domestic raw sewage for secondary treatment at low volumetric hydraulic and organic load by means of adhered biomass aerobic digestion.

Use and maintenance:
The development of the films on the filter media can over time excessively dirty the filter, with the resulting risk of solids being discharged with the treated effluent. In order to avoid an excessively turbid discharge it is advisable to inspect and clean the filter at least once a year. These operations are normally carried out as part of the Imhoff tank inspection and emptying operations. Cleaning is performed by thoroughly washing the filter bed, backwashing where necessary, paying particular attention to remove any accumulations in the inlet and outlet pipes. It should be remembered that in order for the percolating filter to function correctly, the effluent must first be subjected to primary sedimentation treatment in an Imhoff tank or similar installed upstream of the filter.In the case of aerobic percolating filters, it is necessary to install a sedimentation tank downstream which will settle out any sludge residues released by the filter.

Installation: Carefully follow the “INFINITANK INSTALLATION INSTRUCTIONS” provided by ROTOTEC.

INFINITANK GREASE AND GRIT SEPARATORS

Material:
Modular tank for underground installation in linear high-density polyethylene (LLDPE). Fitted with inlet and outlet pipe in PVC. Sized in accordance with UNI-EN 1825-1 and UNI-EN 1825-2 norms to guarantee a sewage retention time of at least 4 minutes at peak flow and more than 15 minutes at mean daily flow rate.

Application:
The grease separator is a physical pre-treatment process that removes oils, foams, greases and all substances with specific weight inferior to that of the effluent.

Use and maintenance:
The substances removed by floatation accumulate at the surface of the grease separator in the form of a surface crust, while the heavier solids settle at the bottom of the tank to form a deposit of putrescible sludge. It is advisable to provide for the periodic removal of the accumulated materials, an excessive accumulation of sludge in the grease separator can cause septic conditions to develop with the resulting malodorous emissions, in particular during the summer. In this respect, it is advisable to contact the appropriately qualified personnel who will remove the accumulated surface mass and settled sludge as well as any film adhering to the surfaces of the tank, paying particular attention to the sediments that could obstruct the effluent inlet and outlet. The frequency of these operations depends on the amount of greases, oils and sedimentable solids present in the effluent. However, it is highly recommended that the separation chamber is inspected every one or two months.

Installation: Carefully follow the “INFINITANK INSTALLATION INSTRUCTIONS” supplied by ROTOTEC.