A soak pit, also known as a soakaway or leach pit, is a covered, porous-walled chamber that allows water to slowly soak into the ground. 6. Soak Pit Design. The wastewater generated in houses like water used for bathing, washing clothes and utensils is commonly disposed in this pit. 51 TABLE 2: Construction requirements for. So soak pits are preferred where the soil is porous in nature. Detention period = 24 hour. If you do not have a central collection facility, how do you dispose of your wastewater? A = Wastewater soak away pit B = Open discharge on the surface C = Irrigate vegetables D = Others (specify)A soak pit is a covered, porous-walled chamber that allows water to slowly soak into the ground and also known as a soak away or leach pit, and the pre-settled sewage from the septic tank is release to the underground chamber from where it infiltrates into the neighboring soils. without contaminating ground water where it is extracted. 2. 4. FREE SEPTIC TANK DESIGN DOWNLOAD. Opening a pit to expose the soil profile is ideal to allow the evaluator to do the examination. 20. The rainfall intensity used in the design of the soak pit shall be that of an event having a duration of '1 hour and a 10% probability of The soak pit should be between 1. Priority must be given to wastewater from the primary treatment unit, which should ensure stormwater is not gathered in the pit resulting in clogging of the pit. Septic Tank: In rural areas where houses are spaced so far apart that a sewer system would be too expensive to install, people install their own, private sewage treatment plants. Design Flows. 6 of Clause E1 of the NZ Building Code to ensure that surface water is discharged without overflowing. In addition, the risk of groundwater pollution will increase with the height of the groundwater level. (i) A minimum liquid depth of 30 inches. Fill the Boulders & Gravel around the ring. 38 times the volume of the hole. The recommended retention time is usually 1 to 3 days, depending on the local regulations and the tank’s design. fAAETI. It is commonly used in areas where the soil has good percolation rates, allowing for effective filtration and treatment of effluent. Part B. We know exactly what it takes to get the job. 2. Soak-pit releases clear and non-harmful water to the ground/environment. On the other hand, leaching pits, primarily ideal for rural or low-density settings, directly discharge wastewater from the dwelling unit into the surrounding subsurface for. . I. 10 m and 1 m depth below the inverted level of the inlet tube. 5 and 4 m deep, but, as a general rule, never less than 2 m above. 1. Original. It is called the detention period when the wastewater in the septic tank intends to store for at least 18 hours to 24 hours. A soak pit is a covered, porous-walled chamber that allows water to slowly soak into the ground and is also known as a soakaway or leach pit, and the pre-settled sewage from the septic tank is released to the underground chamber from where it infiltrates into the neighbouring soils. 15 There shall be no physical connection between a public or private potable water supply system and a sewer. Distances for these onsite wastewater treatment components are given in feet to other site features unless otherwise stated (a few distances may be given in inches). Thus the two pits can be used alternately and perpetually. is then put into a soak pit. After partial treatment the wastewater enters into the soak pit for further treatment by the soil. 5m, there is an increased risk of collapse. (ii) Discharge into other soil absorption systems as soak pit or seepage pits and leaching cess-pools. HKP Infrastructure Pvt. : A soak pit which is also called a soakaway is a closed porous wall chamber that is primary design to allows water to slowly soak into the ground. The water used for washing, dries off soon, without contamination of groundwater by pathogens as minimum distance of few metres is maintained between sources of drinking water and pit location. The wastewater generated in the house from the kitchen and bathrooms has to be disposed of. SOAK PIT : A pit, dug into permeable soil lined to form a covered perforated chamber or filled with sand at the bottom and gravel or broken bricks at the top into which effluent from septic tank or storm water. In areas where the ground water level below 4m a soak pit can be used. Here the design of the soak pit as per. The volume of sewage settlement. , 2014). Scientifically design septic tank involves two or three chamber with an inlet to collect liquid wastages from pour flush cistern and outlet to expel the effluent to soakage pit or sewer. The greywater that passes through the soak pit is filtered. The design of CW is explained in section 4. A biological wastewater treatment process by which biologically active sludge (concentrated biomass) is agitated and aerated with incoming wastewater. The septic tank section is responsible for treating the wastewater naturally by separating the solid waste from the liquids. 50 11 TABLES TABLE 1: Determining capacity of septic tank based on use conditions. Step 4: Calculate the Septic Tank CapacityDesign a cost-efficient soak pit that should not negatively affect soil and groundwater properties and avoid high daily volumes of discharged effluents with the following points: Soakpit needs to be designed for a small family in a rural area having 4-5 members as daily users. Percolation testing for leach lines and horizontal seepage pits. Based on this 24. 7% in percentage terms (CPCB, 2021 ). 5 and 4 m deep. Soak Pit Design. The. Soak pit Design The soak pit, consisting basically of a simple pit (generally approximately 1m3), should be between 1. Sanitation_SoakPitDesign - Read online for free. It is well designed rectangular or circular water tight structure provided with one, two or three chamber used to treat liquid wastes into high settleable solids. It is a simpler form of conventional septic system and hence is also known as a non-conventional septic system. g. Soak pit Design The soak pit, consisting basically of a simple pit (generally approximately 1m3), should be between 1. Combined systems. drainage of roading or driveways. wastewater treatment systems. Anaerobic bacteria decompose the sludge during this time, resulting in sludge. The immersion well should be between 1. It is also called soak pit or seepage pit. Soak Pits are designed to discharge pre-settled blackwater or greywater. In Auckland managing rain or so called “Stormwater” correctly is critical for the cities growth and. Soak pit are best suited to soils with good absorptive properties; clay, hard packed or rocky soils are not appropriate. Centralized wastewater management system is the modern day waste management practice, but the high cost and stringent requirements for the construction and operation have made it less attractive in the under-resourced regions of the world. What is the wastewater from kitchen sinks called? a) Grey water b) Black water c) Yellow water d) Brown water. August 23, 2022. Sludge volume is reduced by microbial action but still needs periodic emptying. Sometimes the effluent of centralized wastewater treatment units or other decentralized primary treated effluents is also soaked through soak pits. T is the detention time ( 1 to 3 days) IF not given take T = 1 day. The retention time is the duration for which the wastewater remains in the septic tank for treatment before it overflows to the soak pit or drainage field. The Soaking pit should be raised above ground level and surface water should not enter into the soak pit. Dry wells (also known as soakaway pits, soakwell, or soak pit), is one of the earliest models of a water runoff management system. A soak pit is an essential part of any home drainage system. In this study, the wastewater collected from a septic tank is passed through a partially converted anaerobic filter, and a vertical flow constructed wetland (VFCW) before being sent to a soak pit. 5 Sqm per head of the user. , for stormwater or wastewater), soil conditions, local regulations, and the volume of water to be managed. g. A soak hollow is one covered, porous-walled chamber that allows water to slowly soak into the ground. As a result, most septic tanks do not conform to the recommended design. 50m from water abstraction points, boreholes, springs. 20m(B) x 1. 1. Social Considerations. The design and sizing will vary. It should be Health Aspects/Acceptance As long as the soak located at a safe distance from a drinking water source pit is not used for raw sewage, and as. The Waimakariri District Council has responsibility for the following functions: Urban stormwater. Soak Pit Soak Pit does not provide adequate treatment for raw wastewater and the pit will clog quickly. 2. 2. (WHO 1992) Overflowing liquid is infiltrated into the ground by a soak pit Accumulated solids. A soak pit – also called a soak away or leach pit – can be. What is a soak pit any home drainage system must have a soak pit. It should be a minimum of 18 m and preferably 30m away from any source of drinking water, such as well, even bore to mitigate the possibility of bacterial pollution of the water supply. It should be located at a safe distance from a drinking water source (ideally more than 30 m). It contains the following information: Design tables for soak pits and infiltration trenches. Design Considerations The soak pit should be flooding or that have high groundwater tables. So we are briefly describing soak pit design and. D. 12,78,379 household and community soak pits. 5m to 4m. ] The writers of the Health Act put it mildly: cesspits and drywells, when used for receptacles of human waste, are a nuisance. m3 Actual volume soakage area of trench in recharge pit design A (T,min) 3m Minimum required soakage area of the trench in recharge pit design AEP % Annual exceedance probability C (req) m3s/L Coefficient of required volume C (storage) Discharge rate for storage expressed as a proportion of peak discharge rate CN Curve number d (device)When wastewater percolates through media-filled soak pits, it is decomposed by micro-organisms attached to media. Your design should: Contain wastewater long enough for maximum removal of suspended solids. The various parts of the septic tank are properly designed as per the standard laid. Dimensions: 1. METHODOLOGY The study was planned during the discussion with the facility about the soak pit undergoing the partial treatment of the effluent water coming out of primary treatment unit. Design Considerations: The Soak Pit should be between 1. The increased contact time with the active biomass (sludge) results in improved treatment. 5 to 3 yrs. D. It essentially consists of a single. • Community Soak pits are usually constructed at the Design Considerations. Gravel and stonebeds. Technology and Program Design 6 Legislation and Standards for Urban Sanitation 11. Suppose there is no need to reuse wastewater collected. Part one of this manual provides a description of the design of WSPs, while Part two provides a detailed description on the. In that case, soak pits can offer a cost-effective technique for partial treatment and a comparatively safe approach of discharging it to the. Steel: TMT (Thermo Mechanically Treated) steel. AS/NZS 1546. Intermediate. Next day, refill the test section with water to a depth at least 300mm (12in). In this Video I will explain about soak pit | soak pit construction | soak pit for septic tank | soak pit for wastewater #SoakPit-----. , 2014 Read- Homemade septic Tank Design! Soak Pit Size. Ensure access for emptying of tanks by vacuum tanker, as well as availability of sludge treatment and disposal. Using a soak pit will help you cut down on the amount of contaminated water released into the environment. 34. 2. A Soak Pit should be used for discharging pre settled black water or grey water. Total volume req = 10200+2400 = 12600 lit or 12. Since the Soak Pit is odourless, installed underground and wastewater kept away from human contact, even the most sensitive communities may have little acceptance issues. Design consideration of Soak Pit. Sealed solid waste storage is an option if soil is. Detention Period = 18 hours. The septic tank was designed to store the wastewater at the minimum period of 18 hours to 24 hours, it is called detention period. Soil absorption system Seepage pit or soak pit: unlined and filled with stone or brick 50 SEPTIC TANK 51. 2. The minimum capacity of the pit should accommodate all the wastewater produced during one washing or in one day, whichever figure is the greater. If none of the options in these tables are appropriate for your needs, then you will have to design your soak pit or infiltration trench by hand. Many people prefer a. This led to breeding of mosquitoes and insects and spread of diseases like diarrhoea. Safety measures. Further, according to the building codes of Bhutan (2002), standard sizes for the building of septic tanks and soak pits are required in order to regulate urban wastewater. ALL DIMENSIONS IN MILLIMETRES UNLESS OTHERWISE INDICATED 1. A soak pit is a covered, porous-walled chamber that allows water to slowly soak into the ground and is also known as a soakaway or leach pit, and the pre-settled. •The flow and characteristics of the wastewater that can be considered for design of septic tank is presented in the Table. Instead of entering the pit, a shovel, probe, or auger should be used in the bottom of the pitWastewater treatment - Sludge, Disposal, Treatment: The residue that accumulates in sewage treatment plants is called sludge (or biosolids). 48 KLD greywater is produced per day. To provide a septic tank soak away where a drain field is not possible. A seepage pit is designed to receive clarified effluent from a septic tank, or if the pit receives only graywater wate then it's called a drywell. 1. 1. In areas where the ground water level below 4m a soak pit can be used. A Soak Pit does not provide adequate treatment for raw wastewater and the pit will clog. (pits, chambers and trenches) that allow infiltration to the ground through their base and sides and that incorporate below ground storage. Soak pit promotes eco-friendly practices by minimizing environmental impact and protecting water sources from contamination. Sludge Digestion Tank. 5 and 4 m deep, and not less. Sewerage systems. As a result of the implementation of this work, approximately 200 litres of grey water/wastewater per school is being recharged into ground on a daily basis, and 53 schools have been benefitted. US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Greywater from the bathroom and kitchen is safely managed and reused by households through construction of soak pits and kitchen gardens to produce. These are used for the discharge of domestic and industrial wastewater. The Function of Soak Pit: A sock pit serves the capacities as given beneath: It gathers the wastewater from the essential treatment unit or homegrown use. Horowhenua District Council require soak pits to be constructed from a perforated 1050 manhole riser placed in a hole to take the initial flow of water fed from sumps with grip traps for right of way collection or directly discharged into a soak pit from roof collection with. The main purpose of the Sewage treatment process is to remove the various constituents of the polluting load: solids, organic carbon, nutrients, inorganic salts, metals, pathogens, etc. Pre-settled effluent from a collection and storage/treatment or (semi-) centralized. Soak Pit - Function, Types & Design. The solids being heavier than thePits prepared within the absorption area often settle after the system has been installed and may disrupt the distribution network. Wastewater. Maintenance Requirement: Periodic removal of screenings and cleaning. _____ should not be placed near water body. The immersion well should be between 1. Soak Pit Design What is a Soak Pit? : A soak pit which is also called a soakaway is a closed porous wall chamber that is primary design to allows water to slowly soak into the ground. ) So: V stor = 0. 9 Fish Pond 156 D. Design Characteristics: BOD Total Suspended Solids Fecal Coliform : : : 170 370 mg/l 250 mg/l 5 x107 MPN/100ml. Design of Soak Pit. 4 m 3. There is no intention to reuse the wastewater that is coming from the primary treatment unit. 3. 5-4 m, depending on the anticipated volume of urine and the. INLET AND OUTLET TEES. 50 m (Hounkpe et al. As a property owner, you are responsible for maintaining your onsite wastewater system and knowing how it works. A Soak Pit is a very low-cost and low-tech solution for discharging wastewater. Based on this 24. If there is no intention or need to reuse wastewater, collected rainwater or gray water, immersion pits can offer an economic opportunity for partial treatment of waste-water or ash from a primary treatment (eg septic tank, double pits for flush toilets, biogas collector, deflector anaerobic reactor, etc. An anaerobic baffled reactor (ABR) is an improved Septic Tank with a series of baffles under which the grey-, black- or the industrial wastewater is forced to flow under and offer the baffles from the inlet to the outlet . Soak pits are appropriate for rural and peri. Greywater Management Wastewater from bathroom, kitchen Wastewater from toilet containing faecal sludge Greywater Blackwater Liquid waste genera on* Management of wastewater from a commercial establishment, howsoever big or small is the responsibility of the concerned establishment. Plasticizers: SP-430 =0. The volume of wastewater shall be determined by one of the following:All domestic waste water treatment systems, including septic tanks, must be registered with your local authority. septic tank, twin-pits for pour-flush toilets, biogas settler, anaerobic baffled reactor, etc. As part of a full drainage system it is an efficient and low environmental-impact way of dealing with surface water (also called runoff, rain water or storm water). IN UNSUITABLE GROUND CONDITIONS SPECIFIC DESIGN IS REQUIRED REFER TO WSA 03 & WSA 04 DRAWINGS FOR GUIDANCE. A cesspit (cesspool) is a holding tank (or pit) built. The sludge can safely be used as manure. Soak pits are appropriate for rural and suburban settlements. CAPACITY OF SEPTIC TANK:-capable of storing sewage flow during detention period &extra volume of sludge for . 250mm. Effluent from the septic tank is not pure thus needs further treatment for which it is sent to the soak pit. 5 and 4 m deep, and as a rule of thumb, never less than 2 m above the highest groundwater table. natural land, is built with a round shape with dry bricks or stones with free mortar together, where water can easily soak to the ground known as soak. The design of the community soak pit is according to the population of village. pvc sn16 unless noted otherwise. Based on this the diameter of the soak pit is given as 1. Septic tanks may be appropriate for situations where the volume of wastewater produced is too large for disposal in pit latrines and water-borne sewerage is uneconomic or unaffordable. 2. Pre-settled effluent from a collection and storage/treatment or (semi-) centralized treatment technology is discharged to the underground chamber from which it infiltrates into the surrounding soil. 5 and 4 m deep, but, as a general rule, never less than 2 m above. Soak pits or infiltration trenches that intercept the water table will fill rapidly and are unlikely to cope with large volumes of wastewater. Need for Soak Pit. 5 and 4 m deep, but as a rule of thumb, never less than 2 m above the groundwater table. Design Consideration of Soak Pit. Opening a pit to expose the soil profile is ideal to allow. “Earlier, grey water was discharged in the open, resulting in waterlogging, bad odour and increased incidence. It should be made sure that only pre-settled black or grey wastewater post-primary treatment is admitted within the soak pit. 1. The scum, composed of waste that’s lighter than water, floats on top. 2. A soak pit or a soakaway is a closed porous chamber that is directly connected to a primary treatment unit of residential or commercial building. Step-by-step sample calculations with full solutions. Septic tanks are a minimum of 2700 litres (650 gallons) for a 2 bedroom house. details a suggested design approach complete with worksheets and design charts to assist applicants to determine which stormwater soakage system should be adopted. 0. IV Soak Pit Design: The soak pit, consisting basically of a simple pit (generally approximately 1m3), should be between 1. 5 and 4 m deep3, but as a rule of thumb, never less than 2 m above the groundwaterThe soak pit is a pit through which the effluent is allowed to filter or seep into the surrounding soil. 80 m, depth = 4. In plants where a certain amount of whey is discharged, the pH of the effluent is reduced to below 6. The rocks and gravel will prevent the walls from collapsing, but will still provide adequate space for the wastewater. 2 The Standard originates from a review of available information on the fate and transport of road contaminants and the design of existing road soakaway systems. A soak pit, also known as a soak away or leach pit, is a covered, porous-walled chamber that allows water to slowly soak into the ground. See details at DRYWELL DESIGN & USES. Prior two are of rectangular shape and later is generally of circular shape. Thus the two pits can be used alternately and perpetually. This Appendix will explain how to design soak pits and infiltration trenches. 402 Biological Wastewater Treatment: Principles, Modelling and Design Aerobic Influent + Aeration (100 kWh) Influent Effluent 10-20 kg COD Effluent 12-10 kg COD Biogas 40-45 m 3 (~ 70% CH 4) Heat loss 100 kg COD Sludge, 30-60 kg Sludge, 5 kg Anaerobic D Figure 16. The following applies to all septic tanks regardless of material. Let take @120 liters per user as i have told you to consider above. 5 and 9. Wastewater is generated in your house from kitchens, bathrooms and laundries. Minimum soakaway drainage field distances. Key Words: Magic Soak Pit, Disposal, Unhygienic Condition Wastewater, Groundwater Recharge. This IS Code provides various requirements that have to be met while constructing a septic tank, so that it meets minimum standards. Infiltration area (iA): The surface area required to infiltrate the amount of wastewater entering the pit. The area of the soak pit does not include the base. Design Considerations: Capacity of septic tank: Capable of storing sewage flow during detention period &extra. A = Stabilization pond B = Soak away pit. Soak Pits are designed to discharge pre-set-tled blackwater or greywater. For individual houses a pit of about IV2 cubic meter of rectangular shape is dugged, filled from bottom to top with large stones, brick bats and gravel, lined with bricks, keeping open the joints for absorption. • Your sites soak pit, if you are not connected to a reticulated storm water system • Unsealed areas (open ground) or where unpiped runoff leaves your site • Storm water treatment systems, for example: • oil or grease interceptors - flow control or shut-off devices on sumps - swales - ponds - filtersFor wastewater samples, 20 (10 from each area) septic tanks were selected for sampling. WA = 540 L / 50 L/m2 = 10. The immersion well, basically consisting of a single well (usually approximately 1 m3), should be between 1. When wastewater passes through the septic tanks, heavier solids sink to the bottom and undergo bacterial digestion. 4. The design of the community soak pit is according to the population of village. 2 Onsite System Design Strategy 4 3 SITE EVALUATION PROCEDURES 3. Topics covered in the orientation session include, but are not limited to the following: 1. design criteria must be applied to the settlement tank and soakaway system. Flow of water is always downward. Detailed characterization data regarding. Today I'm going to show you Exactly how to build a strong Soakaway pit or leachpit or soakpitIs a flooding Bathroom dangerous?Yes If the Bathroom over floods. 5 m and 4 m deep but as a general rule, never less than 2 m above the groundwater table. The area of the soak pit does not include the base. hold point – the contractor shall carry out soakage testing in accordance with the auckland soakage design manual at the proposed soakage pit location with the engineer in attendance. 48 KLD greywater is produced per day. 8m. It is a type of soil absorption system - a smaller version of leach fields and is suitable for treating and disposing of small effluent discharges wherever a. . Depending on usage and how deep they are dug, some pits may last 20 or more years without emptying, but shallow pitsFeature of Soak pit. Using a soak pit will help you cut down on the amount of contaminated water released into the environment. Very low on cost and a simple design for on. However, you as the applicant are responsible for the application of the Manual to your site and making the decision regarding which soakage system is adopted as required. V soak = 15 × 300/1000. 5 to 3 yrs. For safety, an excavator (backhoe) is usually used to dig the pit to five-feet. . 4. 5 to 2 years, when most of the pathogens die off. 2. 5 and 4m deep, but never less than 1. 2. The pit may be lined with. The. As wastewater (greywater or blackwater after primary treatment) percolates through the soil from the soak. It is extremely important that the soil be allowed to soak for a sufficiently long period of time to allow the soil to swell if accurate results are to be obtained. These tables do not cover all possible options. A soak pit, or leach pit, is a covered chamber; typically rectangular, square, or circular with porous-wall to allow the septic tank effluent to slowly soak into the ground. Malik Enroll- 190/11 Roll no. The soak pit is a covered walled chamber that is porous and allows wastewater to slowly soak into the ground after a secondary treatment. A soak pit is constructed in the natural ground by the dry bricks with open joints in a circular shape as shown in the below picture. This option is applicable only in areas of low settlement density and where soils have a high ability to drain effluent away. Pre-settled effluent from a collection and storage/treatment or (semi-) centralized treatment technology is discharged to the underground chamber from which it infiltrates into the surrounding soil. ) Provision of alternative material of magic soak pit. Introduction to Sanitation Technologies 13 Understanding Sanitation Technologies 15 On-Site Systems 18 Off-Site and Hybrid Systems 21 Treatment of Wastewater and Fecal Sludge 22 Reuse of Treated Wastewater and Sludge 25 Summary of Common. You can mix the kitchen wastewater with the soil before planting any plant or sapling. A sewerage system, or wastewater collection system, is a network of pipes, pumping stations, and appurtenances that convey sewage from its points of origin to a point of treatment and disposal. Brick Wall Soak Pit-Brick wall soak pits are square or round-shaped septic tanks. While a septic tank treats and discharges water, a soak pit simply allows water to soak into the ground. Compared to a soak pit, the leach field might be somehow safer, but is considerably more sophisticated in its construction. small or large scale composting, settling - thickening ponds or drying beds). 5/10/06 2 of 10 Water Works Design and Construction Sizing The following are intended to be general guidelines for sizing the most common types of storage tank configurations. C cover with manhole is provided at the top of the tank. Numbers in bold-face are those more-widely accepted or most inquired by our readers. b) pit latrine tank. Design Considerations of Soak Pit Design. . . Keywords. 85 = 10200 lit/day. INTRODUCTION The magic soak pit is an underground structure used to dispose the wastewater. Normally, the chambers are all of the same depth (between 1. If there is no intention or need to reuse wastewater, collected rainwater or gray water, immersion pits can offer an economic opportunity for partial treatment of waste-water or ash from a primary treatment (eg septic tank, double pits for flush toilets, biogas collector, deflector anaerobic reactor, etc. 0m horizontally from any existing or proposed water main. Septic tank,soak pit and gi sheet design Alok Kumar. infiltration is likely to be severely limited. Loose brickbats are laid at the bottom to improve the soaking quality. Deeper tanks provide extra sludge storage, but no credit shall be given toward design. Guidelines for soak pit design, including sizing, are provided in Verification Method E1/VM1 to New Zealand Building Code clause E1 Surface water or can be obtained from your local council. Soak Pit – Need and Functions. A factor of safety of 0. In most cases, this is a disposal field. Where the community lives near dams or river banks that frequently burst during the rainy season. SOAK PIT • A soak pit, also known as a soak awat or leach pit, is a covered, porous-walled chamber that allows water to slowly soak into the ground. To provide effective drainage for areas that flood. To know construction mechanism. This residue is commonly classified as primary and secondary. 20m(L) x 1. the wastewater to pass through. SEPTIC TANK & SOAK PITS B U I L D I N G S E RV I C E S YEAR – 2018-19. the method of magic soak pit for disposal of wastewater. Percolation test waiver procedures. 1. com A soak pit, also known as a soakaway or leach pit, is a covered, porous-walled chamber that allows water to slowly soak into the ground. Wastewater from the primary treatment unit will not be reused. Civix is a team of designers, engineers, and support staff who specialise in designing and installing soak pits. The soak pit is to be a hole filled with rocks. The rainfall intensity used in the design of the soak pit shall be that of an event having a duration of '1 hour and a 10% probability ofAbstract. 5 m diam eter and depth of 3 m trench with 3. (b) The flow allowance used to calculate the system design flow shall beThe design of a septic tank depends on the number of users, the amount of water used per capita, the average annual temperature, the desludging frequency and the characteristics of the wastewater (SASSE 1998) . The pre-treated wastewater from the Imhoff tank requires a secondary treatment (e. a) drainage tank b) pit latrine tank c) harvesting water tank d) septic tank View. 2.