Waste Water Plant

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MARINE CITY

Wastewater Treatment Plant

Wastewater Plant Schematic

Disinfecting Phosphorus Removal Sludge Handling Laboratory Successful Alliance

Introduction New Plant Belle River Pump Station Preliminary Treatment Secondary Treatment

Mission Statement:

"Before Present day society entered the scene, water was purified in a natural cycle. But modern civilization and our intensive use of water, coupled with the resulting pollution, placed a profound burden on mother nature. The Marine City Wastewater Treatment Plant, a modern and well maintained facility ,was built to assist, protect and provide quality protection for a valuable resource, the St.Clair River. Present day technology provides superior waste water treatment and bio-solids removal in a efficient cost effective manner so existing or potential receiving streams are not polluted all while considering citizens cost and esthetic concerns."

Introduction

The original Marine City Wastewater Treatment Plant [WWTP]Was completed in 1958 and expanded in 1970 to assure long-term water quality protection for the St. Clair River. Expanded facilities included grit removal,primary settling, a trickling filter to biologically remove organic matter, final settling tank and chlorination facilities. A Sludge storage tank was added in 1989. Planning for current improvements began in 1989 when City officials realized the need for increased capacity, reliability,and performance of the wastewater system.

Design began in 1990 to meet the National Pollutant Discharge Elimination System (NPDES) permit effluents limits and compliance schedule. The City of Marine City procured a low interest (2%) loan from the State of Michigan Revolving Loan Fund Program for design and construction of the WWTP and sanitary sewer system improvements. Total project cost were $9,100,000 . Revenue generated through City taxes will finance repayment of the loan. Cost for operation,maintenance and equipment replacement will be paid through a sewer user charge system.

The New Plant

The new Marine City WWTP expands treatment capacity to 1,000,000 gallons per day average annual dry weather flow and is designed to meet the anticipated growth needs of the City into the year 2010. Marine City's upgraded treatment facilities will remove solids and organic matter from the wastewater stream. It will also remove phosphorus and ammonia nitrogen compounds. These compounds inhibit recreational use and endanger aquatic life in the receiving stream. The new facilities are designed to effectively meet the stringent water quality standards of the NPDES permit.

The Belle River Pump Station

Improvements to the Belle River Pump Station included a 16-inch force main to the WWTP, an emergency generator, and four new pumps. Piping revisions allowed for elimination of the raw sewage bypass to the Belle River during wet weather events.

Secondary Treatment

Secondary treatment is primarily a biological process in which organic matter and soluble and suspended solids are removed. Biological treatment occurs with-in a three-channel orbal oxidation ditch, which provides a medium where bacteria and microorganisms can feed on the dissolved organic material and ammonia nitrogen. Disc aerators provide oxygen for the microorganisms in the wastewater and mix the contents of the ditch. This process is relatively new in Michigan, but has been used extensively in Europe and other portions of the United States. It offers lower energy cost when compared to other activated sludge systems using diffused air for oxygen supply and mixing. Wastewater flows from the oxidation ditch to the secondary clarifiers, where the microorganisms and heavier solids settle to the bottom. Return sludge screw pumps continually recirculate the settled sludge back to the oxidation's ditch. Periodically, sludge is removed from the clarifiers and disposed of through a sludge handling system. The clarified effluent water passes over the secondary clarifiers weirs and proceeds to the chlorine contact chambers.

Disinfection

Sewage contains many types of bacteria, some of which are potentially harmful to humans and wildlife. Sodium hypochlorite is added to the clarified effluent to kill harmful bacteria as a last measure of protection before the treated wastewater is discharged to the St.Clair River. Sodium hypochlorite was chosen instead of chlorine gas to eliminate the safety concerns associated with gaseous chlorine. Effluent flow is measured and a step-type discharge is provided to raise the dissolved oxygen level in the final effluent.

Phosphorus Removal

Phosphorus is removed in the secondary phase through biological processes in the oxidation ditch or by mixing ferric chloride with the wastewater. Ferric chloride reacts with the phosphorus and forms a chemical precipitate, which is captured as sludge in the secondary settling tanks . A Polymer compound can also be added to aid in settling.

Sludge Handling

Waste Biological organisms from the secondary treatment clarifiers are pumped into a pre-thickening holding tank. With the addition of polymer and mixing of the tank contents, a floc is formed. Small suspended particles collide and form into larger heavier particles or flocs and settle. Further quiescent settling will allow the clear top liquid to be decanted from the tank while the sludge solids are retained for further thickening. The thickened sludge is then pumped to the sludge holding tanks through the use of rotary lobe transfer pumps. In the sludge holding tanks, which provide six months storage of sludge production, the sludge is gravity thickened and further decanted. Finally, every spring and fall, the sludge is pumped into tank trucks. The sludge is then transported to farmland and injected for use as an agricultural fertilizer and soil conditioner. Alternately, the thickened sludge can be pumped to any of the four sludge drying beds. Once dried, the sludge can also be land-applied.

Laboratory

The new facility features a modern laboratory with analytical instruments capable of performing all of the required chemical and biological test accurately and efficiently. Wastewater is tested daily at each stage of treatment process. Samples of the incoming plant flow and the final effluent are continuously pumped to a sample room adjacent to the laboratory. Tests on these samples provide data to verify that each unit process is working properly.

Preliminary Treatment
Mechanical and hydraulic processes remove inorganic particles from the wastewater. Two raw sewage screw pumps elevate the wastewater to allow for gravity flow throughout all the WWTP processes. Flow is first directed through a fine bar screen and then a vortex grit removal system. This innovative design uses less energy than previous grit removal systems that required extensive mixing with air, and allows for the removal of a finer grit, thereby lessening maintenance on downstream pumps and equipment. Screenings removed through the bar screen are conveyed to a dumpster along with the grit. The collected material is periodically transported to a landfill for disposal.

Mission Statement:	"Before Present day society entered the scene, water was purified in a natural cycle. But modern civilization and our intensive use of water, coupled with the resulting pollution, placed a profound burden on mother nature. The Marine City Wastewater Treatment Plant, a modern and well maintained facility ,was built to assist, protect and provide quality protection for a valuable resource, the St.Clair River. Present day technology provides superior waste water treatment and bio-solids removal in a efficient cost effective manner so existing or potential receiving streams are not polluted all while considering citizens cost and esthetic concerns."
Introduction	The original Marine City Wastewater Treatment Plant [WWTP]Was completed in 1958 and expanded in 1970 to assure long-term water quality protection for the St. Clair River. Expanded facilities included grit removal,primary settling, a trickling filter to biologically remove organic matter, final settling tank and chlorination facilities. A Sludge storage tank was added in 1989. Planning for current improvements began in 1989 when City officials realized the need for increased capacity, reliability,and performance of the wastewater system. Design began in 1990 to meet the National Pollutant Discharge Elimination System (NPDES) permit effluents limits and compliance schedule. The City of Marine City procured a low interest (2%) loan from the State of Michigan Revolving Loan Fund Program for design and construction of the WWTP and sanitary sewer system improvements. Total project cost were $9,100,000 . Revenue generated through City taxes will finance repayment of the loan. Cost for operation,maintenance and equipment replacement will be paid through a sewer user charge system.
The New Plant	The new Marine City WWTP expands treatment capacity to 1,000,000 gallons per day average annual dry weather flow and is designed to meet the anticipated growth needs of the City into the year 2010. Marine City's upgraded treatment facilities will remove solids and organic matter from the wastewater stream. It will also remove phosphorus and ammonia nitrogen compounds. These compounds inhibit recreational use and endanger aquatic life in the receiving stream. The new facilities are designed to effectively meet the stringent water quality standards of the NPDES permit.
The Belle River Pump Station	Improvements to the Belle River Pump Station included a 16-inch force main to the WWTP, an emergency generator, and four new pumps. Piping revisions allowed for elimination of the raw sewage bypass to the Belle River during wet weather events.
Secondary Treatment	Secondary treatment is primarily a biological process in which organic matter and soluble and suspended solids are removed. Biological treatment occurs with-in a three-channel orbal oxidation ditch, which provides a medium where bacteria and microorganisms can feed on the dissolved organic material and ammonia nitrogen. Disc aerators provide oxygen for the microorganisms in the wastewater and mix the contents of the ditch. This process is relatively new in Michigan, but has been used extensively in Europe and other portions of the United States. It offers lower energy cost when compared to other activated sludge systems using diffused air for oxygen supply and mixing. Wastewater flows from the oxidation ditch to the secondary clarifiers, where the microorganisms and heavier solids settle to the bottom. Return sludge screw pumps continually recirculate the settled sludge back to the oxidation's ditch. Periodically, sludge is removed from the clarifiers and disposed of through a sludge handling system. The clarified effluent water passes over the secondary clarifiers weirs and proceeds to the chlorine contact chambers.
Disinfection	Sewage contains many types of bacteria, some of which are potentially harmful to humans and wildlife. Sodium hypochlorite is added to the clarified effluent to kill harmful bacteria as a last measure of protection before the treated wastewater is discharged to the St.Clair River. Sodium hypochlorite was chosen instead of chlorine gas to eliminate the safety concerns associated with gaseous chlorine. Effluent flow is measured and a step-type discharge is provided to raise the dissolved oxygen level in the final effluent.
Phosphorus Removal	Phosphorus is removed in the secondary phase through biological processes in the oxidation ditch or by mixing ferric chloride with the wastewater. Ferric chloride reacts with the phosphorus and forms a chemical precipitate, which is captured as sludge in the secondary settling tanks . A Polymer compound can also be added to aid in settling.
Sludge Handling	Waste Biological organisms from the secondary treatment clarifiers are pumped into a pre-thickening holding tank. With the addition of polymer and mixing of the tank contents, a floc is formed. Small suspended particles collide and form into larger heavier particles or flocs and settle. Further quiescent settling will allow the clear top liquid to be decanted from the tank while the sludge solids are retained for further thickening. The thickened sludge is then pumped to the sludge holding tanks through the use of rotary lobe transfer pumps. In the sludge holding tanks, which provide six months storage of sludge production, the sludge is gravity thickened and further decanted. Finally, every spring and fall, the sludge is pumped into tank trucks. The sludge is then transported to farmland and injected for use as an agricultural fertilizer and soil conditioner. Alternately, the thickened sludge can be pumped to any of the four sludge drying beds. Once dried, the sludge can also be land-applied.
Laboratory	The new facility features a modern laboratory with analytical instruments capable of performing all of the required chemical and biological test accurately and efficiently. Wastewater is tested daily at each stage of treatment process. Samples of the incoming plant flow and the final effluent are continuously pumped to a sample room adjacent to the laboratory. Tests on these samples provide data to verify that each unit process is working properly.
Preliminary Treatment	Mechanical and hydraulic processes remove inorganic particles from the wastewater. Two raw sewage screw pumps elevate the wastewater to allow for gravity flow throughout all the WWTP processes. Flow is first directed through a fine bar screen and then a vortex grit removal system. This innovative design uses less energy than previous grit removal systems that required extensive mixing with air, and allows for the removal of a finer grit, thereby lessening maintenance on downstream pumps and equipment. Screenings removed through the bar screen are conveyed to a dumpster along with the grit. The collected material is periodically transported to a landfill for disposal.