Community and domestic level septic tank systems did not have effluent treatment facilities and effluent was being discharged into water bodies without proper treatment. There was no mechanism for de-sludging of the tanks at designated periods or for treatment of sludge before disposal. This had resulted in the risk of contamination of water bodies and water-borne diseases due to disposal of sludge and effluent without proper treatment.
Community-level septic tank systems
In community-level septic tank systems serving large communities, the effluent, although clarified to a large extent, still contains dissolved and suspended organic solids and pathogens requiring additional treatment. The accumulating sludge at the bottom of the tank should be de-sludged and treated at least once in two to three years as per CPHEEO Manual, 2012. The sludge has to undergo further treatment in an STP or a special sludge treatment facility before being suitable for application on land or disposal.
There were 29 community-level septic tank systems (March 2018) serving populations ranging between 300 and 2,000 in five out of 16 test-checked ULBs. The observations in respect of these 29 systems, after joint physical inspections and scrutiny of records, are discussed in Table-2.2.6 below:
Thus, in most cases, the effluent was being discharged into water bodies without any treatment despite having STPs in four out of five ULBs (Ref. Table above). Fifteen out of 29 septic tanks had not been de-sludged since their commissioning (period ranging from eight to 22 years), adversely impacting the effectiveness of the treatment process, thereby causing greater pollution to water bodies. Where tanks were being de-sludged, the disposal of sludge in the open without any treatment would be polluting the soil/ land.
The Principal Secretary, IPH stated (March 2019) that efforts were being made to lift effluent to nearby STPs.
Domestic-level septic tank systems
ULBs are responsible for approving house maps and issuing completion certificates of every new construction within their jurisdiction. As per directions of HPSPCB, ULBs should ensure that every household/ waste generator should be connected with the septic tank (of proper design and having adequate capacity) and soak pit.
The audit conducted (April-June 2018) joint physical inspection and survey in 16 test-checked ULBs of 557 households which were not connected with any sewerage systems and hence, should have had a domestic-level septic tank and soak pit system along with de-sludging/ cleaning of the septic tank once every one/ two years. The following were observed:
• 97 households (17 percent) had not constructed any septic tank and were releasing sewage directly into drains/ nallahs.
• Of the 460 households that had constructed septic tanks, 351 households (76 percent) had not constructed separate soak pits, thereby adversely impacting the effectiveness of effluent treatment.
It was observed that with the exception of three ULBs (Hamirpur, Mandi, and Una), the remaining 13 ULBs were issuing certificates to households without certifying that the household site had been visited and that construction of the septic tank was as per design, indicating that no such verification was being conducted.
• Of the 460 households with septic tanks, 259 households (56 percent) reported that they had not cleaned their tanks. Of the other 201 households, 191 households (95 percent) reported that they were disposing of sludge in the open/ nallahs/ fields, etc.
It was observed that with the exception of one ULB (Shimla), the remaining 15 ULBs were not providing any services for de-sludging/ cleaning of domestic-level septic tanks. None of the 16 test-checked ULBs had devised any mechanism for the treatment and disposal of the sludge collected from these tanks.
The Additional Director, UDD accepted the audit observation. The Principal Secretary, IPH confirmed (March 2019) the facts.
Non-construction of septic tanks and soak pits and disposal of sludge in the open by households was indicative of poor supervision of domestic-level septic tank systems by ULBs. Disposal of effluent and sludge without treatment was certain to affect the quality of groundwater/ surface water/ land and posed the risk of contamination. This was also admitted in an internal report of the IPH Department, which, in the context of outbreaks of jaundice in Shimla during 2007-13, had reported that “There exist no scientific arrangements for disposal of sewage in domestic-level septic tanks constructed by house owners. Resultantly untreated sullage enters into the watershed area of the source, and contaminates the water drawn from that source especially during heavy rains when people tend to clean their septic tanks”.
The cases pointed out are based on the test check conducted by Audit. The Department may initiate action to examine similar cases and take necessary corrective action.
Recommendation: The State Government may ensure the construction of septic tank systems as per norms. Further, ULBs should exercise supervision and control over domestic-level septic tank systems and provide services for the treatment of effluent and sludge before discharge/ disposal either themselves or through outsourcing.