Decentralized Treatment Systems DTS
seecon
international gmbh
Introduction
DTS applications are based on the principles of making of making maximum use of natural of natural gifts like gravity, microbiological activity or temperature. This result in a system which can work without technical energy input (in fact it’s producing energy in form of methane/biogas) of methane/biogas) and needs only minimal maintenance. DTS application provides state of the of the art technology at affordable prices because material/inputs used for construction are locally available.
DTS applications: •
provide treatment for both, domestic and industrial sources
•
are reliable, long lasting and tolerant towards inflow fluctuation
•
do not need sophisticated maintenance
Treatment steps: Without considering facilities for necessary chemical pre‐treatment of wastewater of wastewater from industries, the DTS core system consist of four of four treatment steps: •
Primary treatment and sedimentation
•
Secondary treatment in Anaerobic Baffle Reactor (ABR) and Anaerobic Upflow Filter (AF)
•
Tertiary treatment in aerobic/anaerobic subsurface flow filter (Plated Gravel Filter)
•
Tertiary aerobic/anaerobic treatment Polishing Pond
Reuse: DTS enables reuse of the of the contents of the of the wastewater (water, nutrients and energy) and can therefore be considered as technical option for ecological/sustainable sanitation. DTS applications are designed to meet requirements stipulated in environmental laws and regulations.
Description of the of the treatment modules
The selected treatment modules are based on DTS principles incorporating the following attributes: •
Tolerance to inflow fluctuations
•
Resource efficiency and non‐dependence on energy
•
Minimal maintenance
•
Reliability and longevity
•
Reuse of wastewater of wastewater and its contents
The modules proposed are: •
Biogas Settler
•
Anaerobic Baffle Reactor (ABR)
•
Anaerobic Up flow Filter (AF)
•
Planted Gravel Filter (PGF)
•
Polishing Pond
Biogas Settler The settler can be considered as a gas tight septic tank with low hydraulic retention times. Two main treatment processes take place: First, a mechanical treatment retains contaminants by sedimentation/flotation, and the wastewater from the clarified layer flows through the outlet. Second, biological treatment through anaerobic microorganisms which partially decompose the organic pollutants. The digestion process ensures that the accumulated sludge is reduced and stabilized. Storage volume for sludge is provided for 18 to 24 months, defining the desludging period. Average reduction of organic of organic content (BOD,COD) is between 25 and 40%. The produced methane can get captured in form of biogas of biogas and be used as an energy source in direct application or electricity production via gas‐generator. The settler is resistant to shock load and variable inflow.
Anaerobic Baffled Reactor (ABR) The ABR consists of a of a series of chambers, of chambers, in which the wastewater flows up‐stream. Activated sludge is located at the bottom of each of each chamber. The inflowing effluent is intensively mixed up with the sludge, wherein it is inoculated with bacterial mass which decompose the contained Pollutants. The BOD reduction rate of the of the baffled reactor is up to 90 %. The Baffled Reactor is resistant to shock load and variable inflow, the operation and maintenance is simple and virtually no space.
Anaerobic Up Flow Filter (AF) The anaerobic filter is also known as fixed bed or fixed film reactor and has a similar flow pattern like the Anaerobic Baffle Reactor. Some filter materials such as gravel, rocks or specially formed plastic pieces provide additional surface area for bacteria to settle. Non‐settleable and dissolved solids are treated by bringing them in close contact with a surplus of active of active bacterial mass fixed on filter material. The BOD removal rate is in the range of 70 of 70‐90%. The surplus of activated of activated sludge produced has to be removed in intervals of 1 of 1 to 3 years. The strength of AF of AF lies in its ability to further stabilize (BOD, COD, TSS reduction) low strength wastewater e.g. the effluent from the ABR.
Horizontal Flow Constructed Wetland = Planted Gravel Filter (PGF)
The Horizontal Gravel Filter (HGF) is made of reed of reed planted filter bodies consisting of fine gravel. Bottom slope is 1 %. The flow direction is mainly horizontal. The filter is normally planted with helophytes like cattails or reeds. The main removal mechanisms are biological conversion, physical filtration and chemical adsorption. Mechanisms of BOD of BOD removal are mainly aerobic and anoxic .The function of the of the HGF is mainly post treatment. Reduction rate of BOD is between 75 ‐ 90 %. Reduction of infective of infective organisms is over 95 %. Operation and maintenance of the of the system is simple (mainly garden work). The spatial requirements are compensated by integrating it with the landscapes.
Polishing Pond Polishing ponds are shallow artificial lakes. The removal mechanisms are sedimentation of non of non‐degraded and degraded suspended particles, and aerobic oxidation by intake of oxygen via water surface and photosynthesis of algae. of algae. The elimination of pathogens of pathogens by exposure to UV ray represents the third treatment mechanism and often the most important one. The efficiency of polishing of polishing ponds is strongly related to their surface and their hydraulic retention time. The BOD removal normally ranges between 20 – 20 – 30% and the pathogen removal is 95%.
Treatment efficiency The extent of BOD, of BOD, COD complies with the client’s needs. If designed If designed properly a DTS can reduce BOD
below 10mg/l. Due to the fact that nitrification does not take place in under anaerobic conditions, the effluent water of the of the DTS will content some nitrogen; this water has therefore fertilizing effect and should be therefore get reused for irrigation purpose. The pathogen reduction is in the range of 99.99% of 99.99% to 99.9999% (3 to 6 log); worm eggs, which have statistically the highest health risk, get reduced 100% because of settling of settling process in the tanks and the good filter effect of the of the gravel filter (PGF, HGF).
Projects samples
DTS for People soft in Bangalore 3
Volume: 6m /day Discharge standard: BOD <20mg/l, TSS <30mg/l Challenge 1: The Building is situated in a low lying area; therefore it is not possible to flush the wastewater via gravity into the nearest sewer line. Soak pit was not a solution since the strata is clay.
Challenge 2: No space for a conventional STP. The treatment plant had to get integrated in a narrow space between building and outer walls.
Challenge 3: Since the treatment plant is at the entrance it should be aesthetically pleasing and the STP should be camouflaged. We overlaid the plant with a plastic liner and lawn was developed on it. To reach the manholes in case of maintenance of maintenance of the of the DTS (desludging of the of the tanks) the lawn can easily get rolled up.
DTS for Manipal Hospital in Bangalore
Volume: 600m3/day
The project commence on a PPP (Public
Discharge standard: BOD <20mg/l, TSS < 30mg/l
Private Partnership) with MoEF, Govt. of India, of India, GTZ and Manipal Hospital. Challenge 1: No space since the free area need to be used as parking space. Real estate very expensive. STP is constructed below the car parking
Challenge 2: Wastewater comprises of domestic sewage, laboratory washings and disinfectives. Customized design ensured that the requirement is met.
Challenge 3: Escalating energy costs was a concern. The design was planned to enable capture of the of the gas and produce electricity using biogas generator.
DTS for Aishwarya Amaze Builders
100 Apartment building at Bannnerghatta Road
3
Volume: …50m /day Discharge standard: BOD < 20 mg/l, TSS < 30mg/l
Challenge 1: Very little space available between the wall and the building. Real estate very expensive. We designed a customized solution given the space constraints.
Challenge 2: Since it is a new apartment which needs to be sold it should be aesthetically pleasing and the STP should be camouflaged. Nearly 20 houses overlook the DTS
Challenge 3: Given the water shortage the client wants the treated water to be recycled for toilet flushing. We designed the Plant Gravel Filter solution to address the need. The PGF was planned around the narrow space circling the building.
DTS for a cluster of houses of houses (“Laughing Waters”) in Bangalore 3
Volume: 50m /day Discharge standard: BOD <30mg/l, TSS < 30mg/l Challenge 1: The current Septic Tank was overflowing and the STP implementation has to happen along with the incoming sewage.
Challenge 2: No space was originally allocated for STP. The proposed DTS had to be designed within the area currently occupied by septic tanks.
Challenge 3: There is no space to implement the Plant Gravel Filter module. The design was done to ensure that the system will conform to treatment norms even without PGF.
DTS for Adarsh College of Arts of Arts & Commerce, Badlapur 3
Volume: 8m /day
DTS for a Day School with 2600 pupils. The
Discharge standard: BOD <20mg/l, TSS < 30mg/l
campus gets used for cricket matches and wedding ceremonies with up to 1000 people. Challenge 1: Being a school, the water quality used to fluctuate and cannot be predicted. We designed a solution keeping this variance in mind
Challenge 2: To reduce ground water consumption there was a need to reuse the treated water to irrigate the large campus lawns. The STP was implemented to cater to this requirement.
Challenge 3: Need to demonstrate to students the recycling possibilities. The produced biogas gets used for a gas stove and a gas lamp (for show case) in the nearby Ecosan Exhibition Hall.
Confident Cascade Resort 3
Volume: 20m /day Discharge standard: BOD <20mg/l, TSS < 30mg/l Challenge 1: Being a resort, the water characteristics fluctuate and cannot be predicted. The DTS has been designed keeping this variance in mind. Water is a major requirement
Challenge 2: Since the treatment plant is at the entrance it should be aesthetically pleasing and the STP should be camouflaged. The DTS has been integrated with the existing garden
Challenge 3: The treatment byproducts should be utilized and design should be scalable to cater to future growth. The DTS allows the biogas to be used in the kitchen while the treated water is used for landscaping. The modular solution allows expansion very easily.
Toyota Kirloskar
Volume: 12 KLD Discharge standard: BOD <20mg/l, TSS < 30mg/l Challenge 1: The client has already got a conventional STP which was expensive to maintain. The stakeholders doubted the DTS solution and were worried about the efficacy. The DTS solution surpassed the current benchmark .
Challenge 2: Being a factory, the water quality used to fluctuate and had constituents like paints, caustic soda and bleaching powder. We designed a solution keeping the effluents and variance in mind
Challenge 3: The allocated space was next to the canteen, which means that the system should be odor free. The DTS solution is odorless which satisfied the client.
Pepsico International
Nelamangala, Bangalore
3
Volume: 17m /day Discharge standard: BOD <30mg/l, TSS < 30mg/l Challenge 1: Highly polluting process reject with BOD >55000mg/l and COD > 120000mg/l. Needs to be treated to PCB norms. Domestic sewage also needs to be handled. DTS designed to handle this unusually high load.
Challenge 2: Required to relieve the pollution load on the existing conventional ETP.
Challenge 3: Gaining the trust of the of the client who have already installed a DTS designed by another agency, but is not working as expected. The DTS implemented is working to their satisfaction.
Reitzel India Limited
Kunigal, Bangalore
3
Volume: 45 m /day Discharge standard: BOD <30mg/l, TSS < 30mg/l Challenge 1: Being a fruit processing factory factory, the water characteristics which are “difficult” for biological treatment since it has constituents like preservatives, salt and vinegar. The DTS design had to cater to this situation
Challenge 2: The Effluent treatment Plant has to withstand fluctuation due to variation in process flow caused due to processing various types of fruits of fruits depending on the orders. The DTS implemented is able to operate under this situation at almost twice the peak loading without affecting the quality of treatment of treatment
Challenge 3: The plant is subjected to forced shutdown during lean seasons or no crop production. It should not collapse. The DTS is able to successfully tolerate spells of low of low flows extending more than a month
Karaturi Networks Ltd 3
Volume: 45m /day Discharge standard: BOD <30mg/l, TSS < 30mg/l Challenge 1: Being a food processing centre the water quantity fluctuates and has effluents containing preservatives like salt and acetic acid. DTS is designed as a solution keeping the effluents and variance in mind
Challenge 2: The factory is located in a low lying area subject to flooding. The treatment plant should not be affected by the flooding of the place. The DTS has been designed keeping it above the flood level to ensure failsafe operations
Challenge 3: The plant should be close to the factory to avoid long sewer lines. The DTS is maintained close to the factory but it should not pose any odor problems
