Table of Contents Introduction... 3

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2 Table of Contents Introduction Installation Instructions: First of all the Site evaluation Where the tank should be built? Pipework Construction of a French Drain: (soak away system) French Drain Sketch System drawings: Liter: Litre: Liter:

3 INTRODUCTION What is a septic tank? Your septic tank is the first step in the process of sewage conditioning, in a subsurface disposal system. Without it the untreated sewage would quickly clog the receiving soil and prevent the purification process of leaching and soil percolation. Septic tanks serve three functions: 1. Removal of solids. a. As sewage enters the septic tank, its rate of flow is reduced so that the larger solids sink to the bottom and soaps, grease, and smaller solids rise to the surface. These solids are retained in the tank, and the clarified effluent with suspended and dissolved solids is discharged. 2. Bacterial Action a. The solids and the liquids in the tank are partially decomposed by bacteria and other natural processes. These bacteria are called anaerobic because they thrive in the absence of free oxygen. This decomposition of sewage under anaerobic conditions is termed septic, hence the name of the system (and the cause of the odor). 3. Sludge and scum storage a. Sludge is the accumulation of solids at the bottom of the tank, while scum is a partially submerged mat of floating solids that may form at or near the surface. Space must exist in the tank to store these residues during the intervals between pumping. Otherwise, the sludge and scum will eventually be scoured from the tank and will clog the leach field and receiving soil. In the final stage of disposal the treated effluent from the septic tank is discharged to the leach field or French Drain (See section on French Drain) where it percolates through suitable "septic stone" and finally into the subsoil for further purification. Will The Use of Chemical Additives Solve Septic System Problems? There are currently a wide variety of chemical additives available for use in septic systems. They purportedly help improve the functioning of septic systems. The majority of these additives are a combination of the various types of bacteria commonly found in a septic tank. While it cannot be said that the addition of these additives will in any way harm 3

4 your septic system, there is no scientific documentation that chemical additives will improve its operation. The number of bacteria contained in a chemical additive is very small in relation to the bacteria already present in your septic system. While most cities and even many smaller towns have at least one company that can handle septic tank repairs, the damage to the septic tank might be easy to repair without outside assistance. If one has free time and a moderate amount of skill with tools and/or the ability to follow instructions, there is a good chance that the septic tank repairs can be completed without outside assistance. If one is worried that they may not be up to the challenge, then perhaps calling a firm that specialized in septic tank repairs is a good idea, but what harm could there be in taking a look? Sure, it may not be the most appealing thought, but even investigating the problem can help save one a lot of money. Septic tank or Biogas digester? In certain installations a septic tank digester makes more financial sense than a biogas digester installation. Septic tank digester can process higher fluid volumes (black and grey water combined) and destroy the pathogens more effectively. There are also many other benefits with regard to using a septic tank system on your property. If you are situated in a rural area of South Africa or are running a large corporation, getting a septic tank system will always be beneficial. They are economical and will provide you with an easier way of disposing your wastewater and sewage. 4

5 1. INSTALLATION INSTRUCTIONS: Dig a Rectangular hole approximately: (see table) LENGHT WIDTH DEPTH 1000 Liter liter liter 2500 round 2500mm Trim floor until it s fairly smooth, level and firm. Fill the bottom with 50mm of sand or fine soil (no sharp stones). Please the thank onto this bed and by juggling the tank back and forth, settle the tank horizontally, Check with spirit level along the top of the tank. Back fill the sides of the hole using material free of large lumps or stones. Compact lightly to prevent later subsidence, connect your incoming pipe by pushing it through IN rubber seal (wet seal/pipe for easy fir). Connect your OUT to our pipes leading to the drain/ soak away. Secure the lid on the tank. Mark or provide an access box to the manhole lid for future dislodging. Now connect IN and OUTLET and complete the back fill. IMPORTANT: Your tank is designed to support 200mm soil above it. If it is installed deeper or vehicle traffic passes within 2 Meters of excavation, reinforcing is necessary for the top and sides. Consult a competent building contractor for advice. 2. FIRST OF ALL THE SITE EVALUATION 2.1 Where the tank should be built? The Septic Tank should be: Downhill and the minimum safe distance from any drinking water source. This is site specific and should be established for each water source on the basis of local hydrological and hydrogeological conditions 5

6 A distance of 30 Meters has been suggested by some organizations as standard practice. It is recommended that this figure is taken as a guide to establishing a minimum safe distance, in the absence of local information The soakaway should be: Downhill and the minimum safe distance from any drinking water source At least 3 meters from the septic tank The septic tank should be designed to hold three times the volume of waste water flowing into it every day. This allows the solid material to settle out. It is best to build a septic tank with two compartments, the first compartment being twice the size of the second. 2.2 Pipework When discussing the pipework it can be concluded that installers should add a reinforced concrete roof with an inspection hole over each compartment of the tank. Make reinforced concrete covers with handles for inspection holes. The covers should either be of the sanitary type or be cemented into place using a very sandy mortar mix. This is to stop flies and vermin getting into the tank or odors getting out. The mortar can easily be broken to remove the covers 6

7 3. CONSTRUCTION OF A FRENCH DRAIN: (SOAK AWAY SYSTEM) Where the system over flow for both biogas and septic than digesters (containing human waste), cannot be connected to a municipal waste line, a French drain needs to be constructed These are dimensions for a septic drain. 3.1 French Drain Sketch 7

8 4. SYSTEM DRAWINGS: Liter: 8

9 Litre: 9

10 Liter: 10