Septic Tank Overview

• Perfect sewage treatment solution for houses not connected to sewage network
• Collects and treats domestic wastewater using bacterial process to decompose waste
• Filters dirty water before recycling back into ground
• Usually made of concrete with access covers on top
• Waste treatment occurs in separate chambers inside tank

Rebar Reinforcement Construction

• Steel bars (rebars) reinforce concrete structure
• Welder assembles rods to form cage
• Spot welds rebar with mid welding torch
• Welded cage maintains structural integrity
• Worker measures cage diagonals to ensure straightness
• Rebar spacers placed to keep cage centered in mold and leveled on floor

Formwork Setup

• Crane lowers rebar cage into custom formwork made of high strength steel plates
• Workers close walls around form and secure with heavy duty locks
• Crane lowers machined steel cores to form interior walls of tank chambers
• Rigid plastic tube inserted inside rubber sleeve to create flow hole between chambers
• Worker cuts holes in rebar for access openings using acetylene torch
• Mold allows concrete to flow over rebar and embed access opening covers in septic tank lid

Concrete Pouring Process

• Workers pour over 1,300 gallons of wet concrete into mold
• Use stick vibrator to eliminate air pockets
• Level walls with putty knife
• Mix more concrete and pour over top slab rebar
• Concrete blocks used to prevent plastic covers from floating in wet concrete
• One worker pours concrete while other consolidates mixture with vibrating stick
• Worker levels top of slab with trowel

Tank Removal and Finishing

• After concrete cures, workers strip forms
• Remove concrete tank using overhead crane and compressed air system
• Compressed air forces mold away from concrete tank
• Crane takes strip core away for cleanup
• Worker brushes top of walls and sweeps floor inside tank
• Applies butel rubber tape around top of exterior wall for watertight seal between tank and lid

Lid Installation and Final Assembly

• Overhead crane lifts lid out of formwork and brings to tank mold
• Crane slowly lowers lid onto tank
• Workers keep aligned to ensure proper seal
• Label tank to indicate capacity
• Mold opened revealing finished septic tank
• Rubber sleeve molded into wall ensures watertight connection between pipe from home and tank

Installation and Capacity

• Tank set in ground at client's home using radio remote controlled knuckle boom crane
• Tank provides three bedroom house with fully independent sewage system