STEP Collection Systems and Flow Meters - Alberta...collection systems •septic tanks on each lot...
Transcript of STEP Collection Systems and Flow Meters - Alberta...collection systems •septic tanks on each lot...
STEP COLLECTION SYSTEMS AND FLOW METERS
SHANE SPARKS, P. GEO
SD CONSULTING GROUP
Part 1
INTRODUCTION/OVERVIEW
Wastewater Collection Systems – Types of Sewers
What is a STEP System?
Recent Step Systems in Alberta
Step System Components
Example Projects
Flow Meters
TYPES OF SEWERS
• CONVENTIONAL GRAVITY
• PRESSURE
• SEPTIC TANK EFFLUENT PUMP (STEP)
• GRINDER PUMPS
• SEPTIC TANK EFFLUENT GRAVITY (STEG)
CONVENTIONAL GRAVITY SEWER
Manholes
200 mm Sewer
CONVENTIONAL GRAVITY SEWER
• Low operation and maintenance costs
• Few mechanical parts
• Conventional, proven method
• Contractors are familiar with gravity installations
Advantages:
• Limited by site topography
• Infiltration and Inflow
• Construction impacts are large
• Sewer lines start at >2.5 m and can get deep
• For onsite treatment, large septic tanks required at treatment site
• Lift Stations may be required
Disadvantages:
SEPTIC TANK EFFLUENT PUMP SYSTEMS
STEP SYSTEMS
• Large tanks for solids handling not required at treatment site
• Pumped system follows contours of site – no topographic limits
• Better pretreatment – BOD levels are typically lower
• No I&I
• Forcemain easier to directionally drill
Advantages:
• Tanks, Pumps, and Controls required at each house
• Homeowners can’t “flush and forget”
• Operations and maintenance costs can be higher
• Gravity flow is easy
• Experienced operators and contractor required
Disadvantages:
SMALL DIAMETER GRAVITY SEWER
SMALL DIAMETER GRAVITY SEWER
• Low operation and maintenance fees
• Few mechanical/electrical parts
• Small diameter pipes and fewer manholes
• Able to connect to existing septic tanks
• Much less surface disturbance
• Not as limited by topography
Advantages:
• Interceptor tanks required for each home
• Might have to be buried deep, depending on service and main line depth
• Infiltration and inflow
• Sewer lines should be buried >2.5 m
Disadvantages:
• ALL OPTIONS ARE EVALUATED ON EVERY
PROJECT
• MOST RECENT APPROVALS ARE STEP:
• MODULAR, LOW COST OPTION FOR
PHASED DEVELOPMENTS
• LARGE PORTION OF COST DEFERRED
TO HOMEOWNERS AT TIME OF
CONSTRUCTION
• ELIMINATES THE NEED FOR LARGE
PRIMARY TREATMENT TANKS AT THE
TREATMENT SITE (CAN BE A HIGH
COST THAT IS RESPONSIBILITY OF
DEVELOPER)
WASTEWATER COLLECTION
SYSTEMS
• SEPTIC TANKS ON EACH LOT
(OR SOME COMBINATION)
WITHIN THE DEVELOPMENT
• SMALL DIAMETER FORCEMAIN
TAKING WASTEWATER TO
TREATMENT, OR REGIONAL
LINES
• EACH TANK OUTFITTED WITH
SUBMERSIBLE EFFLUENT STYLE
PUMP (OR PUMPS) TO
PRESSURE EFFLUENT
• TANKS INCLUDE FILTERS AND
CONTROLS
WHAT IS A STEP SYSTEM?
COMPONENTS OF A STEP SYSTEM
• SERVICE W/CLEANOUT FROM
SOURCE
• SEPTIC TANK (ONE OR TWO
COMPARTMENT
• PUMP VAULT W/FILTER
• SUBMERSIBLE EFFLUENT PUMP
• DISCHARGE PIPING
• CONTROL PANEL
• VALVE ON CONNECTION TO MAIN
LINE
• MAINLINE
PUMP AND DISCHARGE ASSEMBLIES
STANDARD DISCHARGE
ASSEMBLIES
HANGING DISCHARGE
HANGING DISCHARGE ASSEMBLES - INSTALLED
STEP SYSTEM CONTROLS