Table of Contents

## How is sludge calculated?

Calculation : The daily sludge mass produced = ( 100,000 ) ( 0.080 ) = 8,000 kg dry SS / day. Since 97 % MC is 3 % SC or approximately 30 kg dry SS / m 3 sludge, the daily volume produced is 8,000 / 30 = 267 m 3 .

**How do you calculate return activated sludge?**

The second approach to determine the best return activated sludge rate is by using the solids mass balance equation….How to Determine the Ideal Return Sludge Flow Rate (RAS)

Measuring Parameter | Typical value (mg/L) |
---|---|

MLSS | 2000 – 3500 |

MLVSS | 1500 – 2500 |

SS (Suspended solid) | 6000 – 8000 |

VSS (Volatile Suspended Solid) | 4500 – 6000 |

**How is sludge loading rate calculated?**

The concentration of BOD (in mg/l) in the influent can be used to calculate the total BOD load per day being treated. This is simply done by multiplying the BOD in mg/l by the daily effluent volume in cubic metres (m3) and dividing the product by 1000.

### How is BOD loading calculated?

The BOD loading is calculated by multiplying the concentration (mg/l) of BOD entering the aeration tanks by the influent flow per day (millions of gallons per day, or MGD) to the aeration tanks by the weight constant of 8.34 pounds per gallon of waste- water (Equation I.

**What is a good SVI?**

SVI = 100 to 200 mL/g. Most activated sludge plants seem to produce a clear, good-quality effluent with an SVI in this range. The sludge typically settles more slowly and traps more particulate matter as it forms a uniform blanket before settling.

**How do I reduce SVI?**

Raising the amount of MLSS (reducing waste rates) changes the density of the floc, creating a heavier sludge particle. The more dense the particle, the more likely it will settle faster. The higher milligram per liter MLSS reduces the SVI result.

## What is Mlvss in aeration tank?

The amount (mg/L) of organic or volatile suspended solids in the mixed liquor of an aeration tank. This volatile portion is used as a measure or indication of the microorganisms present.

**What is Formula A in wastewater treatment?**

The maximum storm flow received at a treatment works is calculated by a formula known as Formula ‘A’. This sets the minimum level at which the wastewater is sufficiently diluted by rainwater so as to avoid pollution of the receiving watercourse when overflowed from the sewer.

**How do you calculate TSS in wastewater?**

TSS in mg/L can be calculated as: (dry weight of residue and filter – dry weight of filter alone, in grams)/ mL of sample * 1,000,000.

### What is overflow rate?

Overflow rate is an empirical parameter describing the settling characteristics of solids in a specific wastewater. Overflow rate is defined as the volume of water flow per unit of time divided by the surface area of the settling basin. It is usually expressed as a velocity in feet per second.

**What is COD load?**

Chemical Oxygen Demand (COD) was defined as the measured amount of oxygen needed to chemically oxidise the organics present in wastewater. The less polluted the wastewater is, the less oxygen needed to chemically oxidise the organics present hence the less or smaller the COD value.

**What is SV30?**

The SV30 is a settling rate test. When mixed liquor is poured into a graduated settling vessel (large graduated cylinder or single purposed SV30 container); it is allowed to settle, undisturbed, for 30 minutes. Some operators record the solids volumes at 5 minute intervals to give a settling rate plot.