In UAE the A house owner cannot get rid of the sludge their septic tank sludge left in the tank. There is plenty of bacteria in the first flush, so there’s no need to “leave some”. Nothing but human waste and toilets paper should be flushed. This means, no wipes, no septic tank system additives, no coffee grounds, don’t use the garbage disposal, etc. Nothing you add will make it work better and some things you add can hurt the septic tank system.The septic tank should be pumped out regularly, Septic Tank System Maintenance for details on how often, based on size of tank and number of occupants.
If the septic tank does not have a riser, I strongly suggest you have one installed. Getting Rid of the Septic, Sludge & Scum from Septic Tank.
If you know exactly where the septic tank system is located, DO NOT drive anything over any part of the septic tank system. At worst this can crush what you drive over and cause serious problems, including the possibility of replacing parts or all of the septic tank system. At best, it compacts the soil, making it harder for the septic tank and sewage system to work. Having said that, you should never build anything within 10 feet of any part of the septic tank system. No deck over the septic tanks!
If you don’t know where the septic tank system is located, contact your health department or contact septic tank cleaning service company in UAE (or whoever regulates septic systems in your area) to find out where it is. Treat the septic system like it’s alive (because it is). No harsh chemicals, no paint, etc.