By comparison it found that number of parameters controlled under QCVN 40 is more than that of under QCVN 14. As results, following recommendation was made.
In principle, a QCVN on urban wastewater is not yet specified. It is necessary to:
Issue a specific QCVN for urban wastewater or;
Supplement a specific regulation: where there is only domestic effluent without industrial effluent, it may be applied QCVN 14, but in case of having both domestic and industrial effluent, it should apply QCVN 40. In fact in some urban areas, beside domestic wastewater, it may mixed with industrial effluent (for example Binh Hung Hoa station in HCMC announced as 40% of rainwater; 40% of domestic and 20% for industrial effluent).
Treatment processes of WWTPs are shown in the Table 7. 4. Design Parameters and Treatment Processes.
In Vietnam, WWTPs for urban areas have just operated in recent 10 years. The WWTPs are being constructed under ODA projects with technology design and equipment provided by various companies in the world. The number of WWTPs not yet many but applied many types of technology treatment process, including:
Biological lagoons/ stabilization ponds:
Aerobic, facultative pond;
Trickling filter (TF).
CAS (Conventional Activated Sludge);
AAO (Aerobic – Anaerobic - Oxidation);
OD (oxidation ditch (circulate));
SBR, ASBR (Sequencing Batch Reactor).
Many projects on construction of WWTPs would certainly be carried out in the coming years. The Ministry of Construction should evaluate effectiveness in term of economic and technical then provide guidance on selection of treatment processes that appropriate with the conditions in Vietnam.