WASTEWATER ENGINEERING TREATMENT SYSTEMS (PART 1)

Dilution

earliest form of disposal

SEWERAGE SYSTEM; SEPTIC TANKS

WHEN ___________ IS NOT AVAILABLE, BUILDINGS ARE REQUIRED TO HAVE THEIR PRIVATE DISPOSAL SUCH AS ___________ OR IMHOFF TANKS

SEPTIC TANKS

serves as a basic and primary treatment for sewage

* REVISED NATIONAL PLUMBING CODE OF 1999
* SANITATON CODE OF THE PHILPPINES


17. Sewage Collection and Disposal, Excreta

Disposal and Drainage
* UNIFORM PLUMBING CODE OF THE PHILPPNES 2013

Standards for SEPTIC TANKS

DENR Administrative Order No. 34 Series of 1990

REVISED WATER USAGE AND CLASSIFICATION/WATER QUALITYY
CRITERIA AMENDING SECTION NOS. 68 AND 69, CHAPTER IIl OF THE
1978 NPCC RULES AND REGULATIONS

Section 68. Water Usage and Classification.

The quality of Philippine waters shall be maintained in a safe and satisfactory condition according to their best usages. For this purpose, all waters shall be classified according to the following beneficial usages:

DENR Administrative Order No. 35 Series of 1990

Revised Effluent Regulations of 1990

DAO 2016-08

Water Quality Guidelines and General Effluent Standards of 2016

May 24, 2016

approved date of DAO 2016-08

Ramon J.P. Paje

Secretary of DENR that signed DAO 2016-08

Atty. Juan Miguel T. Cuna

Asst. Secretary and concurrent EMB Director

May 30, 2016

Publication date of DAO 2016-08

Assimilative Capacity

refers to the amount of contaminant load that can be discharged to a specific water body without exceeding the water quality guidelines.

municipalities; communities

Wastewater collected from _________ and _________ must ultimately be returned to receiving waters or to the land or reused.

Flowsheet

is a graphical representation of a particular combination of unit operation and processes

Process Loading Criteria

key criteria used as a basis for sizing the individual unit operation and processes.

Solid Balance

determined by identifying the quantities of solids entering and leaving each unit operation or process. Such information must be available to (1) assess the need for sludge storage facilities and their capacity, and (2) to determine the proper size of the sludge piping and pumping equipment.

Hydraulic Profiles

used to identify the elevation of the free surface of
the WW. These profiles are prepared for:

(1) to ensure that the hydraulic gradient is adequate for the WW to flow through the treatment facilities by gravity,

(2) to establish the head requirement for the pumps where pumping will be needed, and

(3) to ensure that the plant facilities will not be flooded or backed up during periods of peak flow.

Plant Layout

the spatial arrangement of the physical facilities of the
treatment plant in the flowsheet. The overall plant layout includes
the location of the control and administrative buildings and other
necessary buildings.

Screening

Removal of large floating, suspended and settleable solids

Bar racks and screens of various description

Treatment Devices for Screening

Grit Removal

Removal of inorganic suspended solids

Grit Chamber

Treatment Devices for Grit Removal

Primary Sedimentation

Removal of organic/ inorganic settleable solids

Primary Sedimentation Tank

Treatment Devices for Primary Sedimentation

Aerobic Biological Suspended Growth Process

Conversion of colloidal, dissolved land residual suspended organic
matter into settleable biofloc and stable inorganics

* Activated sludge process units and its modifications,
* Waste stabilisation ponds,
* Aerated lagoons

Treatment Devices for Aerobic Biological Suspended Growth Process

Trickling filter, Rotating Biological Contactor

Treatment Devices for Aerobic Biological Attached Growth Process

Anaerobic Biological Growth Process

Conversion of organic matter into CH4 & CO2, and relatively stable organic residue

* Anaerobic filter,
* Fluid bed submerged media anaerobic reactor,
* Upflow anaerobic sludge blanket reactor,
* Anaerobic rotating biological contactor

Treatment Devices for Anaerobic Biological Growth Process

Anaerobic digestor

Treatment Devices for Anaerobic Stabilization of Organic Sludges

Unit Operations

Methods of treatment in which application of physical forces predominate.

Unit Processes:

Methods of treatment is which the removal of contaminants brought about by **chemical or biological** means.

Unit Operation

the treatment or removal of contaminant is brought about by the physical or mechanical sources.

Unit Process

The treatment **occurs predominantly due to chemical and biological reactions.**

Physical Unit Operations

treatment methods in which the application of physical forces predominate. Because most of these methods evolved directly from man's first observations of nature, they were the first to be used for wastewater treatment.

Screening

Racks or bar screen are the 1st step in WTP. They are used to remove large objects

Grit Removal

It is used to remove heavy material such as sand, gravel, eggshell, etc.

Primary Sedimentation

used to remove settleable solids

Filtration

is u**sed to polish the effluent**. Total suspended solids and turbidity are removed.

Reverse osmosis or ultrafiltration

It is a demineralization process applicable to production of high quality water from effluent. The water is permeated through semipermeable membrane at high temperature.

Chemical Unit Processes

treatment methods in which the removal or conversion of contaminants is brought about by the addition of chemicals or other chemical reactions.

Chemical Precipitation

Treatment is accomplished by producing a a chemical precipitate
that will settle.

Adsorption

Removal of specific compounds from the WW on solid surfaces using the attraction between bodies

Disinfection

It is used to to reduce the number of water borne pathogens in the
effluent.

Breakpoint Chlorination

Ammonia nitrogen is oxidized to nitrogen gas by breakpoint chlorination in a mixing basin.

Suspended Growth Biological Reactor

It is used to remove dissolved organics. Principal variation is **activated sludge.**

Attached Growth Biological Reactor

It is used to remove dissolved organics. Principal variation is **trickling filter.**

Nitrification

The process is used to convert ammonia to nitrate. Achieved in suspended or attached growth biological reactor.

Denitrification

Nitrite and nitrate are reduced to nitrogen gas by microorganisms. It is achieved under anaerobic condition in suspended or attached growth reactors,

* Physical Unit Operations
* Chemical Unit Processes
* Biological Unit Processes

classification of treatment methods

Biological Unit Processes

treatment methods in which the removal of contaminants is brought about biological activity or action of microorganisms.

Preliminary treatment

____________ provides protection to the WTP equipment

* Screening
* Flow measurement
* Solids grinding
* Grit Removal
* Equalization

process included in Preliminary treatment

Preliminary Treatment System

System is designed to:
Physically remove or cut up the larger suspended and floating materials

Preliminary Treatment System

Remove the heavy inorganic solids and excessive amounts of oil and grease.

* Flow measurement devices and regulators (flow equalization)
* Racks and Screens
* Comminuting Devices
* Tanks

Preliminary System Components

Screening

treatment used for the **removal of coarse and settleable solids by inception.**

Racks or Bar Screen

composed of parallel bars or rods which maybe hand cleaned or mechanically cleaned

Fine Screens

wire/cloth mesh; perforated plate

Coarse Screen

screen with a size of 6 to 150mm

Fine Screen

screen with a size of < 6mm

Microscreen

screen with a size of < 50µm

* Hand cleaned
* Mechanically cleaned

type of Coarse Screen

* Chain driven
* Reciprocating rake
* Continuous belt

type of mechanically cleaned coarse screen

* Static wedgewire
* Drum type
* Step type

type of fine screen

Screenings

the materials collected from bar screen

Screenings

usually removed and deposited into containers or dumpster

dissolved oxygen

If wastewater backs up in the sewer, ____________ can be depleted, resulting in septic conditions.

Hydrogen Sulfide (H2S)

it is produced by septic wastewater

Hydrogen Sulfide (H2S)

A toxic compound that smells like **rotten eggs** and can harm concrete, metal and paint.

Septic shock loads

_____________ can result in poor quality plant effluent

Flow Measurement

flow rate needed for efficient operation, chemical addition, etc.

* Chlorination
* pH adjustment

operations that need flow rate for good operations

Flow measurement

it is a legislative requirement

* Avg. Daily Flowrate
* Peak Hourly Flowrate
* Max. Daily Flowrate

types of WW Flowrate used in Process Design

Avg. Daily Flowrate (ADF)

average flowrate over a period of time

Peak Hourly Flowrate (PHF)

highest flowrate measured in 24 hr period.

Max. Daily Flowrate (MDDF)

maximum daily design flow over a period of time.

* **V**enturi meter
* **P**arshall flumes
* **W**eir (i.e. V-notch)
* **M**agnetic & Sonic meters

flow measuring devices

Solids Grinding or Comminution

grinding of coarse solids to a more or less uniform size

Comminutors

devices used to cut up the solids in wastewater

Barminutor

a combination of bar screen and comminutor

bar screen; 15-30 minutes

The ________ traps the rags and a rotating cutter runs down the screen to cut the rags every ________

Grit Chamber

an enlarged channel where the velocity of wastewater flow is controlled to allow only the heavier solids to settle out.

2 feet per second; 1 foot per second

The downward slope of a sewer line must be sufficient to maintain a minimum velocity of _________ in the pipe. This velocity is maintained until the flow enters the treatment plant. The grit is removed from the flow as it passes through a grit chamber. The velocity in the grit chamber is reduced to about _________.

Grit

refers to heavy inorganic and organic matter that will not decompose in later biological treatment stages

* Sand
* Gravel
* Glass
* Egg shells
* Seeds
* Coffee grounds

examples of Grit

* Horizontal-Flow Grit Chamber
* Aerated Grit Chamber
* Circular Grit Chamber

types of Grit Chamber

organics

Too many ________ in the grit can lead to odor and disposal problems.

landfill

Grit can attract rodents and flies, so it must be sent to an approved ______ for proper disposal.

* Comminutors
* Grinders

types of shredding devices

Comminutors

are devices with cutters and screens that shred or comminute the solid and leave the in the wastewater stream.

Equalization Basin

maintains a constant volumetric flow of wastewater from pretreatment to other downstream operation. It dampens hydraulic or flowrate variations.

preliminary treatment

Odors during ___________ can originate from several sources: ***Influent wastewater, plant recycle streams, screenings, grit, and unusually strong water****s* such as those from a septage-receiving station

1. Chemical addition
2. Odor masking
3. Gas collection and Treatment

Odor Control

* Chlorine and chlorine compounds
* Hydrogen peroxide
* Metal salts (iron, zinc and copper)
* Ozone
* Strong alkalies (sodium hydroxide and lime)
* Nitrate

Common Chemicals used to Control Hydrogen Sulfide

* Wet Scrubbers
* Activated - Carbon Type Systems

Gas Collection Units

Wet Scrubbers

Require sodium hydroxide and sodium hypochlorite