Types of Trickling filters By: Prof. Akshay Chiplunkar

Types of Trickling Filters RIZVI COLLEGE OF ENGINEERING Types of Trickling Filters They are classified based on 1)According to Organic & Hydraulic loadings 2)According to the number of units used in series According to Organic & Hydraulic loadings Low rate trickling filters 2)High rate trickling filters 3)Intermediate rate trickling filters 4)roughing trickling filters According to the number of units used in series Single stage trickling filters 2)Double stage trickling filters Prof. Akashy Chiplunkar Sub:- EE-I

RIZVI COLLEGE OF ENGINEERING W Rate Trickling Filters (LRTF) These relatively simple treatment units that normally produce a consistent effluent quality even with varying influent strength. ➢ They are generally not provided with recirculation of effluent. ➢ Depending up on the system, wastewater is applied intermittently ➢ With proper loadings the LRTF, including primary and secondary sedimentation units, should remove from 80 to 85 percent of the applied BOD. ➢ Prof. Akashy Chiplunkar Sub:- EE-I

High Rate Trickling Filters (HRTF) RIZVI COLLEGE OF ENGINEERING High Rate Trickling Filters (HRTF) When recirculation is used, the hydraulic loading per unit area of filter media is increased. As a result, higher flow velocities will usually occur causing a more continuous and uniform sloughing of excess growths. High-rate trickling filters, including primary and secondary sedimentation, should, under normal operation, remove from 65 to 85 percent of the BOD of the wastewater. Prof. Akashy Chiplunkar Sub:- EE-I

RIZVI COLLEGE OF ENGINEERING Roughing Filter Roughing filters are high rate type filters designed with plastic packing. In most cases roughing filters are used to treat wastewater prior to secondary treatment. low energy is required for BOD removal of high strength wastewaters as compared to activated sludge process because the energy required is only for pumping the influent wastewater and recirculation flows Prof. Akashy Chiplunkar Sub:- EE-I

RIZVI COLLEGE OF ENGINEERING Prof. Akashy Chiplunkar Sub:- EE-I

Single stage trickling filter RIZVI COLLEGE OF ENGINEERING Single stage trickling filter Here only single filter is adopted When two or more filters are required they will provide in parallel Generally recirculation is not provided Prof. Akashy Chiplunkar Sub:- EE-I

Single stage filter with recirculation RIZVI COLLEGE OF ENGINEERING Single stage filter with recirculation Prof. Akashy Chiplunkar Sub:- EE-I

2) Double stage trickling filter RIZVI COLLEGE OF ENGINEERING 2) Double stage trickling filter This system consist of two filters in series Here re-circulation of effluent is normally adopted Prof. Akashy Chiplunkar Sub:- EE-I

Two-stage filter with recirculation RIZVI COLLEGE OF ENGINEERING Two-stage filter with recirculation Prof. Akashy Chiplunkar Sub:- EE-I

RIZVI COLLEGE OF ENGINEERING Advantages  The effluent obtain is highly nitrified and stabilised  They can remove about 80% of suspended solids and about 80% BOD  The rate of loading is in comparison with contact bed process  It is simple, cheap and does not required any skilled supervision  They are self cleansing  Mechanical wear ant tear is less as it contain less mechanical equipments  It require less electricity power to run mechanical equipment  The moisture content of sludge obtained from this is as high as 99% Prof. Akashy Chiplunkar Sub:- EE-I

RIZVI COLLEGE OF ENGINEERING Disadvantages  High capital costs  The loss of head through the filter system is high thus making the automatic dosing  It requires large area  Final settlement in humus tank necessary  This process may develop odur and fly nuisance Prof. Akashy Chiplunkar Sub:- EE-I