Sewage Treatment Plant
In Malaysia, extensive use has been made of primary treatment systems such as communal septic tank's and Imhoff tanks. Large urban areas have Individual Septic Tanks. There are over one million individual septic tanks in Malaysia. These tanks discharge an effluent rich in organic material. This could cause public health and environmental problems in urban areas. The standardisation of the types of plants used will hopefully make Malaysia's sewerage system more efficient. The management of domestic sewage in Malaysia has been changed by these extensive programmes. Changes can be expected to the entire sewerage infrastructure. Estimates have been made of the number of public treatment plants in Malaysia.
Imhoff Tanks (IT)
Imhoff tanks are a simple form of sewage treatment plant. The operation consists of removing scum, reversing the flow to keep an even distribution of sludge, and removing sludge. Imhoff tanks make up 24 per cent of all sewage treatment plants in Malaysia. They don't provide a long-term solution for sewage treatment. If the tanks are not maintained, the effluent can rapidly degrade. Two chambers are positioned above each other. The upper compartment has an opening in it. Solids form in the lower chamber. The lower tank is filled with gas. The upper tank has scum. ITs are usually used to service small communities. They are cheap to operate and maintain. ITs only partially treat sewage. The effluent from these tanks will not meet the requirements of the DOE. Small package treatment plants have more recently supplanted ITs as the popular method of servicing small communities.
Oxidation Pond (OP)
Oxidation ponds are a popular method of sewage treatment for small communities because of their low construction and operating costs. Oxidation ponds make up 12 percent of all sewage treatment plants. Maintenance and desludging are required in order to maintain the Standard B effluent level.
One or more shallow ponds may be part of the OPs. The growth ofbacteria andalgae are dependent on each other. The degree of treatment depends on the weather. They can't consistently achieve a good standard of effluent. The gradual phasing out of this type of treatment plant is necessitated by this variation in performance.Depending upon the design, OPs must be desludged approximately every 10 years.
Package/Mechanical Sewage Treatment Plants
Small communities can often be served by package plants, which can be used to serve up to 5,000 people. The same operational and maintenance care is required for package plants as for conventional treatment plants. No sludge is produced by package plants. Care must be taken in using package plants where large variations in flow are experienced, as well as adequate provision for sludge removal, scum and grease removal and the proper control of air supply.