Septic tanks provide primary treatment, handling basic solids separation, while advanced systems (e.g., biofilters) offer secondary or tertiary treatment for stricter MECP discharge limits (e.g., CBOD5 <10 mg/L, TSS <10 mg/L). Tanks are simpler and cheaper (installation ~$5,000-$15,000) but may need larger drainfields in clay soils. Advanced systems suit sensitive sites but cost more ($20,000+). Canadian Shield Consultants customizes solutions, often combining tanks with EZflow or pressurized flow dividers for optimal performance in diverse landscapes.