Sequencing batch reactor process/ Sludge drying, Recycling drying

This article is about sequencing batch reactor process which is one of various activated sludge method in wastewater treatment. This is a method consists with a sequence of filling wastewater, aeration reacting, settling, and drawing clarified water (treated effluent). Also, this can be used as advanced wastewater treatments which remove phosphorus and nitrogen.

In this wastewater treatment method, initial settling tank and final settling tank normally used in conventional activated sludge process are not required. After wastewater is filled into reaction tank and aeration, wastewater purification with activate sludge (microorganisms), sludge settling, and drawing treated effluent are proceeded, then these processes are repeated. This reaction tank is called batch tank.
It has advantages that denitrification caused by anaerobic state during wastewater filling and settling can be expected, settling rate of sludge improved since settling time can be made longer, and system configuration can be simple while one tank is used as both aerobic tank and settling tank. Since scums often float during settling, treated effluent is drawn from underwater (between sludge surface and water surface). Scum removing apparatus is required to remove scums on water surface.
Compared with conventional activated sludge process, facility is simpler and maintenance is easier. Also, time of aeration, settling etc., can be set freely according to amount and quality of filling wastewater. It can be said that this method requires director’s ability as well. This method is often used in effluent treatment facility whose size is small.

■ Scum
Thick sponge layer which is formed on surface inside of tanks, together with floating matters and carbon dioxide gas generated as bacterial digestion by coliform bacteria, urea splitting organisms, etc. proceed.

■ Sludge
A general term of raw sludge, settled sludge, digested sludge, waste sludge etc. It is sometimes meant to be sludge settled at bottom layer as antonym of scum.
Normally, scum suggests bubbles or floating matters risen by bubbles, and sludge indicates settled sludge or sludge suspended under water.

Types of waste water treatment / sludge drying, slurry drying, waste drying

Water in the sludge thickened in the sludge thickener tank are removed at dehydration process to a certain degree.
However, moisture content is normally more than 80% and the sludge still has adhesiveness and stickiness. Also, latter processes are not easy because of influence of flocculants. Our drying apparatus of KENKI DRYER with international patented technology can surely dry any sticky, adhesive and viscus sludge, and also materials in liquid state like slurry, without clogging inside of the dryer. Also, because of its simple structure, its price is low and apparatus cost of the dryer can be retrieved by reducing industrial waste disposal cost within 3 years. Dried materials can be recycled as fuel, bacterial fertilizer, soil conditioner, etc. since component of the material is hardly changed because of its low-temperature drying method.
It can be applied to a system with pyrolysis apparatus as well.

Sludge drying

Applications