TREATMENT OF HOSPITAL WASTEWATER

Name- Tabish.I.MalikEnroll- 190/11Roll no.- 52Sec- A

Wastewater composition refers to the actual amounts of physical,

chemical and biological constituents present in wastewater.

Hospital wastewater may contain various potential hazardous materials

including, microbiological pathogens, radioactive isotopes, disinfectants,

drugs, chemical compounds and pharmaceuticals.

The major aim of wastewater treatment is to remove as much of the

suspended solids as possible before the remaining water, called effluent,

is discharged back to the environment.

The selection of suitable treatment technology and proper treatment of

hospital wastewater is essential.

As solid material decays, it uses up oxygen, which is needed by the

plants and animals living in the water.

Fisheries -Clean water is critical to plants and animals that live in water.

Wildlife Habitats-Our rivers and ocean waters teem with life that

depends on shoreline, beaches and marshes.

Recreation and Quality of Life-Water is a great playground for us all.

The scenic and recreational values of our waters are reasons many people

choose to live where they do. Visitors are drawn to water activities such

as swimming, fishing, boating.

Health Concerns

If wastewater is not properly treated, then the environment and human health can be negatively impacted

decaying organic matter and debris can use up the dissolved oxygen in a lake so fish andother aquatic biota cannot survive

excessive nutrients, such as phosphorus and nitrogen (including ammonia), can cause over-fertilization of receiving waters, which can be toxic to aquatic organisms, promoteexcessive plant growth, reduce available oxygen, alter habitat and lead to a decline incertain species

chlorine compounds and inorganic chloramines can be toxic to aquatic invertebrates, algaeand fish

bacteria, viruses and disease-causing pathogens can pollute beaches and contaminateshellfish populations, leading to restrictions on human recreation, drinking waterconsumption and shellfish consumption

other substances such as some pharmaceutical and personal care products, primarilyentering the environment in wastewater effluents, may also pose threats to human health,aquatic life and wildlife.

Sher-e-Kashmir Institute of Medical Sciences, located at Soura, Srinagar

(J&K) is a reputed post graduate institute for training, research and

patient care.

The construction of SKIMS commenced in the year 1976 & the institute

was partially commissioned on 5th December 1982.

This waste water from the main supply sewer is directly fed to the sewage treatment plant

(SPT). The feeding is done in two phases. The various components and the various

operations that are carried out are described as follows:-

MAIN SEWER – A sewer is an underground conduit or drain through which sewage is carried

For carrying the waste water in SKIMS Hospital, cement concrete main sewer has been

provided.

The main sewer carries wastewater from laboratories, toilets, kitchens, bathrooms,

wastewater from other domestic and medical activities.

Main sewer in SKIMS

The water from the main sewer is then divided and distributed in two phases. Phase 1 consists of a primary sedimentation cum storage tank, an aeration tank and a clarifier/secondary sedimentation tank. The phase 2 consists of a screening chamber, a grit chamber, an aeration tank and a clarifier/secondary sedimentation tank. The description of these two phases has been provided as follows.

PHASE 1

PRIMARY SEDIMENTATION TANK CUM STORAGE TANK

They are usually rectangular or circular

Most sedimentation tanks are constructed with gently sloped bottoms

The present sedimentation tank as is a rectangular type reinforced concrete primary

sedimentation tank

The tank is 13 m long , 2 m wide and 2.6 m deep

The detention period corresponding to the tank is 2.5 hours

The sludge moves to hoppers by gravity, where it is removed

Primary sedimentary tank cum storage tank

AERATION TANK

the water that overflows from the primary sedimentation tank is allowed to fall to the

aeration tank

Two mechanical horizontal axis type aerators are provided in the tank

The water in the aeration tank is aerated for about 6 hours.

There are pontoon aerators also present which are used whenever the need arises.

Aeration Tank Pontoon Aerators

SECONDARY SEDIMENTATION TANK/CLARIFIER

Activated sludge process is undergone in this tank as the efficientseparation of the biological waste is necessary

The secondary clarifier is a rectangular cement concrete structure with alength of 2.8 m breadth 2.4 m and depth 3 m

The Phase 1 of the treatment plant has a capacity of processing 12 lac litersof wastewater per day

Secondary Sedimentation Tank/Clarifier

The part of wastewater that does not go into the phase 1 is treated in phase 2

SCREENING CHAMBER

The main sewer feeds all the waste water to a rectangular conduit called

screening chamber. Screening is the first treatment station, both for surface and

wastewater. Its purpose to:

Protect the structure downstream against large objects which could create

obstructions in some of the facility's units,

Easily separate and remove large matter carried along by the raw water, which

might negatively affect the efficiency of later treatment procedures or make their

implementation more difficult.

Screening Chamber

GRIT CHAMBER

Sewage consists of a considerable amount of grit which consists of sand, gravel,

silt, ash, cinders, clinkers, egg shells etc.

Grit removal is necessary to protect the moving mechanical equipment and pump

elements from abrasion and accompanying abnormal wear and tear, to reduce the

formation of heavy deposits in pipes, channels and conduits, and to reduce the

frequency of the cleaning of sludge digesters.

Grit Chamber

AERATION TANK

After the grit chamber, the waste water is allowed to pass into an aeration tank

The principle of working of this aeration tank is similar to that of phase 1

Aeration Tank

SECONDARY CLARIFIER TANK

The secondary clarifier tank in phase 2 is similar in working and construction to

that of phase 1. Only the capacity is different

The phase 2 of the treatment plant has a capacity of treating about 6 lac liters of

wastewater per day

The treated wastewater from the two phases is then separately taken to the sludge

beds and from sludge beds to the soak wells

SLUDGE BEDS

The sludge in both the phases is applied on the sludge drying beds.

The purpose of the sludge drying beds is to dewater the sludge

There are 7 no. of beds provided at the present site and each bed has the

dimensions of 4.5mx6m.

These beds consist of a 30 cm thick layer of sand and gravel on specially

prepared open beds. The sludge is applied on this layer and is allowed to dry.

All the drainage from the beds/drains is collected in a pipe and returned to the

secondary clarifier tank of the phase 2 and again processed as discussed above,

and the cycle continues

Pick-up trucks are used for hauling the sludge cakes.

Sludge Beds

SOAK WELLS

The effluents from the secondary clarifier tanks in phases 1 and 2 are allowed to

enter the soak wells

There are 8 no. of soak wells present at the present site.

Only a little amount of effluent is absorbed in the soak pits and a major portion

remains unabsorbed.

The unabsorbed wastewater effluent is collected and discharged directly into the

adjacent Anchar Lake

Soak Well

SHORTCOMINGS IN THE PRESENT WASTEWATERTREATMENT FACILITY

•So all the units are lacking the potential required for the treatment of thewastewater from the SKIMS complex.

•Sludge from the primary sedimentation tank of Phase I is disposed off inopen. This may result to be hazardous for the occupants.

•The screens of the screening chamber are not cleaned at regular intervals andthey were found to be clogged.

•Grit from the grit chamber is not taken out regularly

•Sand is not replaced in the sludge beds regularly.

•The soak wells are not cleaned at regular intervals. This has resulted in theirclogging. So the effluent remains unsoaked and almost all the effluent isdisposed off in the nearby Anchar Lake.

•Since the effluent from the treatment facility has to be finally discharged intothe neighboring Anchar Lake, it must be free from all virus and other infectiouselements. The present treatment plant is lacking such a facility.

THANK YOU