No discharges from systems of sewage disposal for commercial building into watercourses shall be made unless provided with treatment as approved by the state department of health and the state water resources commission. No sewage disposal system shall, after the effective date of the regulation, be constructed or rebuilt for any commercial buildings without compliance with the following subdivisions, unless otherwise approved by the director of health. Connections shall be made to public sewers if available.
(A) The location of the disposal system shall comply with the same requirements as those listed above, except that in the case of discharges from laundromats or other commercial or industrial establishments discharging substantial quantities of detergents, the disposal system shall not be permitted, unless special plans are prepared and carried out in accordance with requirements of the local director of health with due regard to the seepage quality of the soil and location of wells. Disposal systems receiving substantial quantities of detergents shall be located at least 200 feet away from any well used as a source of drinking water.
(B) The septic tank shall comply with § 50.12 with regard to construction details and shall have a minimum liquid capacity of 2 cubic feet per employee or equal to the average 24 hour flow, whichever is greater. In no case shall a septic tank be installed with a liquid capacity less than 100 cubic feet. For very large commercial buildings, special arrangements may be required by the director of health. In the case of restaurants, laundromats, toilets for public use, or other types of establishments where water use and sewage flows will depend on the extent of public use or employment of water uses especially pertinent to the type of establishment in question, special allowances for capacities of disposal units and area for future expansion shall be provided as approved by the director of health.
(C) Seepage systems for commercial buildings other than restaurants* and laundries* shall be designed in accordance with the following table:
Minimum uniform seepage rate minutes to drop one inch | Sewage application in gallons to one square foot of effective seepage area; bottom area of trenches, bottom area plus side area of leaching wells below inlet, or 1/3 of gross bottom area of seepage bed |
3 | 3.0 |
5 | 2.5 |
10 | 1.75 |
15 | 1.4 |
20 | 1.1 |
25 | .9 |
30 | .8 |
More than 30 | Special consideration needed to avoid nuisance conditions. In some soils it may be impracticable or impossible to use subsurface disposal. |
(D) Sewage disposal facilities such as privies and other than of the water-carriage type shall be installed only with the permission of the director of health and in accordance with his requirements.
(E) No ground water drainage or drainage from roofs, roads, cellars or yards, or flow of industrial wastes or other liquids that will adversely affect the operation of a system for domestic sewage disposal or cause an overload on the system, shall be discharged into or near a sewage disposal system for a commercial building. The drainage or liquid shall be disposed of separately subject to any requirements considered necessary by the director of health.
('66 Code, § 57-18)
*Editor's Note:
Additional seepage area shall be provided due to clogging characteristics of waste.