Term
| biosolids are solid waste products that are |
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Definition
| ...suitable for further beneficial use. |
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Term
| Volumes of primary sludges depend on |
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Definition
| ...infow, influent suspended solids, efficiency of the primary sedimentation basin. |
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Term
| Variables that influence the production of secondary sludges are |
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Definition
| ...the flow, the BOD loading, efficiency of removing BOD, growth rate of bacteria. |
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Term
| The primary function of sludge thickening is to |
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Definition
| ...reduce the sludge volume to be handled by subsequent processes. |
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Term
| If gasification occurs due to anaerobic conditions, |
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Definition
| sludges are difficult to thicken. |
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Term
| As the temperature of the sludge increases, the rate of biological activity |
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Definition
| ...increases and the sludge tends to gasify and rise at a higher rate. |
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Term
| Possible causes of solids rising to the surface of a gravity thickener are: |
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Definition
| Gasification, septic feed, blanket disturbances, chemical inefficiencies, excessive loadings. |
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Term
| To correct solids rising to the surface of a gravity belt thickener: |
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Definition
| Increase withdrawal rate, increase sludge pumping from clarifier, lower collector speed, increase chemical feed rate, lower flow if possible. |
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Term
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Definition
| Basket centrifuges, scroll centrifuge, disc nozzle centrifuge. |
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Term
| Basket Centrifuges operate in a batch mode while scroll and disc nozzle types operate |
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Definition
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Term
| Centrifugal thickening is affected by: |
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Definition
| Type and age of sludge, solids and hydraulic loading, bowl speed, pool depth and scroll speed, size and number of nozzles, chemical conditioning. |
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Term
| centrifuges are not commonly used to thicken primary sludge because |
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Definition
| ...the inlet assemblies clog easily. |
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Term
| Factors that affect gravity belt thickeners are: |
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Definition
| Belt type, chemical conditioning, belt speed, hydraulic and solids loading. |
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Term
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Definition
| sludge with an excess of free water is discharged from the gravity belt thickener. Reduces effluent quality. |
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Term
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Definition
| ...the slowest the operator can maintain without washing out the belt. |
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Term
| if a gravity belt thickener frequently washes out, the operator should check: |
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Definition
| The polymer dosage, hydraulic loading, solids loading, belt speed, belt washing equipment. |
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Term
| Factors affecting anaerobic digestion: |
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Definition
| Sludge type, digestion time, temp, mixing. |
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Term
| Factors affecting aerobic digestion: |
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Definition
| Sludge type, digestion time, digestion temp, volatile solids loading, quantity of air supplied, D.O |
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Term
| Two chemicals used to stabilize sludge are |
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Definition
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Term
| Sludge conditioning methods: |
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Definition
| Chemical treatment, thermal treatment, wet oxidation, elutriation. |
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Term
| Chemical tanks should be covered to prevent foreign material from entering and possibly clogging equipment. Polymers must be covered to |
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Definition
| ...protect from ultraviolet sun rays. |
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Term
| The performance and efficiency of thermal conditioning systems are affected by: |
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Definition
| The concentration and consistency of sludge, reactor detention times, reactor temp and pressure |
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Term
| The performance of Wet Oxidation units are dependent on: |
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Definition
| The concentration and consistency of the feed sludge, reactor detention time, reactor temp and pressure, quantity of air. |
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Term
| Elutriation improves the dewaterability of sludge by |
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Definition
| ...washing out the fine, difficult to dewater solids. |
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Term
| The primary objective of sludge dewatering is to |
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Definition
| ...reduce sludge moisture and consequently sludge volume. |
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Term
| Processes used for sludge dewatering: |
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Definition
| Pressure filtration, vacuum filtration, centrifugation and sand drying beds. |
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Term
| secondary sludge does not dewater as readily as primary sludge because |
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Definition
| ...secondary sludge contain fine, low density solids that have large surface areas and large quantities of water associated with them. |
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Term
| As the belt tension increases, the pressure on the sludge . |
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Definition
| ...increases and more water is generally squeezed from the belt, which results in dryer cakes |
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