8/12/2019 sludge floting root case stady _Fact Sheet Karapakkam

1/2

CASE STUDYFACT SHEET

Client ID: M/s. Scope International

Karapakkam, OMR,

Chennai

Date: 8-3-2014

Activity: 140KLD capacity Sewage Treatment Plant Renovation & process efficiency improvement

Target of the Activity &

Improvement Area

Process Quality Reuse OptionMandatory

of TNPCB Cost Effectiveness

Aim:

Improve the existing STP (capacity of 140 KLD), Biological activity and eliminate the existing upsets in

STP and match the mandatory requirements of the TNPCB. Reuse the treated effluent for toilet flushing

and garden irrigation purpose.

Present Status:

Existing STP impose to treated 120KLD 140KLD Waste Water, against actual design capacity of

60 - 70KLD. Present treated effluent not satisfied regularitary requirement. Poor Biological &

mineralisation. Sludge floating in clarifier tank. It is case to filter chocking, frequent media replacement

and upset the treated water quality. Not able to reuse the treated water.

Observations - Technical:

Why did sludge float Denitrification in wrong place

Nitrification convert Ammonia to nitrate Without oxygen the settling tank, nitrate will denitrify providing nitrogen gas. The gas bubbles float the sludge blanket. Why the Denitrification in wrong place? Excess TSS (Sludge) & untraped oil & grease enter to the equalisation tank and aeration tank. It

is case to overload to Bacterial activity.

There is no anoxic Zone in excisting process. Untraped oil & grease upsets the biological activity. The flow pattern is not even. Peak flow rate is high and no adequate collection tank. The

existing collection tank is too small.

8/12/2019 sludge floting root case stady _Fact Sheet Karapakkam

2/2

Analysis (Why why)

Case: Filters are frequently chocking and non compliance of treated water quality.

Why-1 Why sludge accumulating in the treated water storage tank

Why-2 Why sludge floating in settling tank DenitrificationWhy-3 Why Denitrification wrong place MLSS growth is not sufficient poor biological

activity and mineralisation.

Why-4 Why mineralisation get upsets High TSS and oil & grease.

Why-5 Why high sludge and oil & grease enter the process cycle No efficient oil & grease

and sludge trapping also no an anoxic zone provided in the process system.

Root case:

1) No provision for FOG (Fat, oil & grease)

2) No Ananoxic Zone provided.

3) Not adequate air distribution system & air diffusers in Aeration Tank & Equalisation Tank

4) No sufficient attached growth media (MBBR media & Biodec) in Aeration tank &

Equalisation tank.5) There is not consent flow pattern.

6) No chemical dosing system in settling tank for sludge settling.

7) No Nitrate recirculation system installed.

8) No efficient sludge (MLSS) recirculation.

Counter Measures (Problem Solving Solution)

1. Improve the oil, grease, sludge trapping system is existing plant.

2. Provide adequate attached biogrowth media (MBBR media + Biodec) in Aeration &

Equalisation tank.

3. Install new adequate Air diffusers and Air distribution system.

4. Provide/arrange anoxic zone in the system.

5. Control the flow pattern evenly through the day. Provide additional capacity of sewagestorage tank.

6. Install newly recirculation system (pumps) for sludge and nitrate water recirculation.

Bench Mark:

Active the treated effluent for reuse as per TNPCB Norms

BenefitsP Q C O&M M

Process (P) Achieve the biological activity

Quality (Q) Produce the reuse water as per PCB standards for Toilet

flushing & Gardening

Cost (C) Reduce the water outsourcing cost for toilet flushing, garden

irrigation and reduce the replacement cost of filter media.

Operation & Maintenance

(O&M)

Ensure trouble free plant operation and operator friendly

environment.

Mandatory (M) Comply the TNPCB stipulated Norms.