Improving Septic Tank Performance By A New Rational Design Approach

Project and Seminar Materials for Civil Engineering CE

Improving Septic Tank Performance By A New Rational Design Approach


This study was aimed at developing a rational approach to septic tank design in order to reduce health risks associated with improperly treated effluent especially in developing countries. To this end, several research tools including questionnaires, pilot scale study and model formulation were employed. Questionnaires were used to conduct a preliminary study with a view to ascertaining people‟s perception with regard to septic tank design, use and maintenance. This preliminary study revealed that the septic tank is a poorly designed and grossly overlooked but indispensable waste management facility. Pilot scale studies were conducted to monitor physicochemical and microbial parameters.

A sludge accumulation model was formulated from first principles by applying material balance to a model septic tank. The model was calibrated using data from three different septic tank audits spanning 3 years, 5 years and 8 years respectively and involving over 1000 septic tanks. A correlation coefficient of R = 0.98 was obtained between measured and calculated sludge accumulation data. The sludge accumulation model showed that sludge does not accumulate at a constant rate as is usually assumed but rather at a reduced rate over time.

The sludge accumulation model was compared with two existing but purely empirical models namely: Weibel‟s model derived in 1955 for the US Public Health Service and Bound‟s (1995) model. Finally a rational approach to septic tank design was developed. Design charts and a Microsoft Excel based design programme were produced to aid the unlearned designer and the computer literate designer respectively.

Chapter One


1.1 Background Of The Study

The septic tank system is the most widely used onsite treatment system for domestic wastewater. In fact, most developing countries (Nigeria inclusive) lack the technology and economic power to construct and operate sewerage systems for conveyance of domestic wastewater to central sewage treatment facilities, so a greater population rely on the septic tank system for sewage treatment. It is an enclosed receptacle designed to collect wastewater, segregate settleable and floatable solids (sludge and scum), accumulate, consolidate and store solids, digest organic matter and discharge treated effluent (Bounds, 1997).

In the United States only, over 50 million people use the septic system (Collick et al., 2006). According to Fidelia (2004, in Burubai et al., 2007), over 46% of the Nigerian population use the septic tank system. The septic tank system was once thought to be a temporary solution to domestic wastewater treatment and disposal. This was true until 1997 when the United States Environmental Protection Agency and Congress officially recognized the system as a sustainable, long-term solution for treating wastewater.

The septic tank is an anaerobic reactor due to the insufficiency of oxygen concentration to act as electron acceptor. The wastewater is degraded by micro-organisms aerobically while the C, CO2 SO4 act as electron acceptors to form CO2, H2, CH4 and S2- (sulphides). At the same time, most of the organic N is converted to NH+4 (inorganic). The effluent flows into the drain field where aerobic degradation occurs due to abundance of oxygen in the unsaturated soil layer. The C in the wastewater is now oxidized to CO2 while NH4+ is oxidized to NO2- thus raising the nitrate level of the sewage to about seven times the limit acceptable for dumping water (10mg/l). The H+ released from the oxidation of NH4+ now reduces the pH of the effluent.

Improving Septic Tank Performance By A New Rational Design Approach

Project Material Download

3,000 Naira

The complete material will be sent to you in just 2 steps.

Quick & Simple…

Step One Purchase

Make payment of ₦3,000: through USSD Transfer, Bank Mobile App, ATM Transfer, or POS Transfer to:

Access Bank PlcAccount No.: 0811003731
Name: Samphina Academy
Account Type: Current

Or Click Here to pay with Debit Card

Click Here to pay with Debit Card ($15)
GHANA – Make Payment of 60 GHS to MTN MoMo, 0553978005, Douglas Osabutey 


Step Two Purchase

Send the following details through Text Message or WhatsApp Messenger | +234-8143831497

  • Payment Details 
  • Email Address 
  • Improving Septic Tank Performance By A New Rational Design Approach

The complete material will be sent to your email address after receiving your payment information | T & C Apply

  Contact Our Help Desk

You may also like:

⚠️ Need a different topic? Perform a quick search

Get A Complete Business Plan For Any Business In Nigeria

Business Plan for Businesses in Nigeria

  Business Plans in Nigeria


This research material “Improving Septic Tank Performance By A New Rational Design Approach” is for research purposes and should be used as a guide in developing your research project / seminar work. For no reason should you copy word for word (verbatim) as will not be liable for any who copied the material.

The aim of providing this material is to reduce the stress of moving from one school library to another all in the name of searching for research materials. This service is legal because, all institutions permit their students to read previous projects, books, articles or papers while developing their own works. According to Austin Kleon “All creative work builds on what came before”. is only providing this material “Improving Septic Tank Performance By A New Rational Design Approach” as a reference for your research. The paper should be used as a guide or framework for your own paper. The contents of this paper should be able to help you in generating new ideas and thoughts for your own research. Use it as a guidance purpose only.

Samphina Academy

Samphina Academy is an Online Educational Resource Center that is aimed at providing students with quality information and materials to aid them in succeeding in their academic pursuit.