Lecture 4. Community Wastewater Treatment Management

The Islamic University of Gaza- Environmental

Engineering Department

Wastewater Management- EENV 6306

By

Husam Al-Najar

Scope of Application

On-Site

Rural - Municipal

Urban - Municipal

Industrial

Decentralized wastewater systems collect, treat, and reuse or dispose of

wastewater at or near its point of generation.

It include systems that treat wastewater from individual homes or buildings as

well as cluster systems that treat wastewater from groups of two or more

houses.

Unlike centralized urban wastewater treatment systems, decentralized systems

treat wastewater close to the source, typically using small pipes for collecting

small volumes of domestic wastewater.

Most cost-effective option especially in rural areas and hilly terrain.

Cost-effectiveness depends on a number of factors like population size and

density, topography, distance to an existing centralized system

Introduction

Advantages of Decentralized Wastewater Treatment

Often more affordable for small communities

Achieves high removal rates for most pollutants

Less hydrological impact

Can be integrated into a flexible wastewater system

Can be used as a tool to manage development

Reduce sewer networks

Involve local labour and material available

Construct what requires low maintenance and no energy

Generate water and nutrients for irrigation in agriculture and food-

garden

Requires greater awareness and participation of homeowners

Less familiar to engineers

Funding challenges

Lack of management structures

Fragmented regulatory structure

Disadvantages of Decentralized Wastewater Treatment

Potential threat to ground water quality

Can be harder to document treatment effectiveness

No dilution benefit

Risk of failure concentrate

Barriers to Implementation

Lack of Knowledge and Public Misperception

Homeowners and developers think that houses with centralized

systems will carry higher property values and have greater acceptance

Legislative and Regulatory Constraints

Lack of Management Programs

Liability and Engineering Fees

Unwillingness of homeowners and developers to accept the liability

associated with unfamiliar treatment systems

Financial Barriers

The funding agencies generally do not assist privately owned systems.

Five Management Models for community wastewater

Treatments

Model 1 - Homeowner Awareness

Individual OSSF owned and operated by homeowners

Use in areas of low environmental sensitivity

Treatment technologies limited to conventional systems

Maintenance reminder notification

Model 2 - Maintenance Contract

Homeowner system ownership

Professional maintenance

Complex OSSF design such as ATU

Licensed technicians provide proper and timely maintenance

Individual contracts with individual homeowners

Model 3 – Operating Permits

Annual permit renewal to assure system performance

Suitable for increased environmentally sensitive areas

Performance based designs with management controls similar to Model 2

Individually owned OSSF systems

Model 4 – Responsible Management Entity Operation and Maintenance

Decentralized systems

May be combined with individual OSSF systems

Highly reliable operation and maintenance

Water quality and sensitive environmental areas

Operating permits are issued to the RME instead of individual homeowners

Model 5 – Responsible Management Entity Ownership

Suitable for decentralized systems

Not suitable for individual OSSF’s

Systems are owned, operated and maintained by the RME

Removes property owners from responsibility for the system

Greatest assurance of system performance in the most sensitive of environments

Functions of RME Districts

Notification

Asset Inventory

Certification

System design and installation

Monitoring

Plan review & construction inspection

Reporting

Operation and Maintenance

Education

Inspections

Successful RME Attributes

Financial capacity Governance capacity Technical capacity Managerial capacity

Well defined mission,

objectives and goals

Sufficient political will

exists

Preexisting laws

sufficient to grant the

RME authority to

accomplish it’s mission,

objectives and goals

Operation outside

traditional health

department paradigm

Big picture focus and

NOT micromanagement

Set fees and price

structure

Biological

unit

processes

Chemical

unit

processes

Mechanical

unit

processes

Component

uniformity

System type

and

compatibility

A paid manager

Effective and timely

collection

enforcement

Strong board,

annual performance

reviews

Use generally

accepted accounting

principles and good

record keeping

Strong team of

professional

consultants

Long term and

contingency plans

Long-term financial planning

Sufficient cash flow to be self-sufficient

Establish reasonable and sustainable monthly charges

Independent financial oversight

Funds escrowed monthly for replacement cost

Annual audit and performance review

Recommendations for RME’s

Existing development using existing treatment systems – Model 3

Existing development using new treatment systems – Model 4

New development using new treatment systems – Model 5

START

Define Service

Area

Determine number of

Connections

Sufficient political will exist

Existing laws in place to

provide sufficient legal

authority to the new

RME

Petition for RME creation

and authorities

Develop mission

objective &Goals

RME Startup

STOP

Select RME legal structure

Develop required technical, managerial

and financial capacity

Develop short and long term plans and

Contingencies

This chart makes certain

assumptions regarding the

service area and system size,

age and type

Continue

Continue

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Try Again

On site treatment systems configurations and

technique

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