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Wastewater Treatment Process

Screenings Removal

Mvc-141f [1]The wastewater passes through an Aquaguard Screen® removal system which uses bar screens to remove large debris which could damage plant equipment, located further downstream. This debris is cleaned and hauled to an approved land fill.

Clarification

Mvc-116f [2]The clarifiers slow the flow allowing heavy particles to settle to the bottom of the clarifier tank. The solids or sludge are pumped to the sludge thickener for further treatment.

Biofiltration

Mvc-113f [3]The biofilter continually distributes water from the clarifiers over rocks which provide a home for microorganisms that break down organic material into simpler inorganic chemicals. The biofilter conditions mimic the environment of rocky stream beds and ocean coasts.

Biotower-Nitrifiction

Mvc-104f [4]The biotower distributes the water over sheets of corrugated plastic. Bacteria living on these sheets convert ammonia in the wastewater to nitrates, a form of nitrogen that is non-toxic.

Secondary Clarification

Mvc-116f-1 [5]The clarifiers slow the flow allowing heavy particles to settle to the bottom of the clarifier tank. The solids or sludge are pumped to the sludge thickener for further treatment.

Sand Filtration

SAND3 [6] sandfilter [7]The Mt. View Sanitary District utilizes a Dynasand ® filter system. The system removes solids from the secondary effluent achieving a clarity that allows downstream disinfection with ultraviolet light. The Dynasand ® filter is a continuous-backwash, upflow, deep-bed, granular-media filter system. The filter media is continuously cleaned by recycling the sand internally through an airlift pipe and sand washing. The cleansed sand is redistributed on top of the sand bed, allowing for continuous, uninterrupted flow of filtrate and reject (backwash) water.

Ultraviolet light disinfection [8]

The Peyton Slough Marsh Complex [9]

Sludge to Biosolids

Clarification

Mvc-116f [2]The clarifiers slow the flow allowing heavy particles to settle to the bottom of the clarifier tank. The solids or sludge are pumped to the sludge thickener for further treatment.
Thickening

Sludge Thickening

thickener [10]The Sludge Thickener is another settling tank which further separates solids from the liquid. The sludge from the bottom of the thickener is sent to the Primary Digester. The overflow of water from the thickener is sent back to the Clarifiers.

Sludge Digestion

Mvc-117f [11]Sludge solids are pumped into anaerobic digesters where bacteria, in an oxygen free environment, break down solids producing methane gas, carbon dioxide and stabilized organic solids. The methane gas is used to fuel the plant boiler which maintains the desired temperature for the bacteria to thrive.

Sludge Dewatering

centconv [12]The Mt. View Sanitary District has used a Belt Filter Press for the last 16 year to dewater the sludge. With this unit we are able to get approximately 15 to 18 % solids. In the fall of 2000 the District will switch to using an Alfa Laval Sharples® Centrifuge. The Centrifuge will enable us to achieve a higher solids concentration and reduce hauling costs. How does a Centrifuge work?

Biosolids

biosolids [13]Solids from the digester, which are called biosolids, are dried before they are recycled as soil amendments or used as alternative daily cover at a landfill. Here an Operator uses a new piece of equipment called a Brown Bear to windrow the sludge. This allows for better drying and therefore less volume and lower hauling costs.