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APPENDIX 1 - WASTEWATER TREATMENT FACILITIES DESCRIPTION AND LIST OF CITY FACILITIES PROPERTY SECTION 1.1. WASTEWATER TREATMENT FACILITIES (A) The purpose of this Appendix is to provide a summary description of the Wastewater Treatment Facilities. It is not intended to describe all elements that comprise the Wastewater Treatment Facilities. The Wastewater Treatment Facilities generally include the facilities and equipment described in this Appendix or in the Service Contract. (H) The Company shall provide the Contract Services for the entire Wastewater Treatment Facilities and the Facilities Site, whether or not a particular element of the Wastewater Treatment Facilities is identified herein. SECTION 1.2. FACILITIES. The City owns the San Marcos Wastewater Treatment Facilities (the "Facilities") located at 720 River Road, San Marcos, Texas. The Facilities, which were renovated, expanded and commissioned in 1999, comprise an advanced tertiary wastewater treatment facility rated at 9.0 mgd on a maximum monthly basis (7.2 MGD annual average day flow and 18.0 MGD two hour peak flow) and serve a population of approximately 42,000 customers. Effluent from the Facilities is sold for re-use or discharged into the San Marcos River through a submerged outfall. (A) Sludge. The Facilities have a conventional activated sludge operation consisting of the headworks, primary clarifiers, aeration basin, secondary clarifiers, final effluent fIlters, and disinfection. The solids are currently stored and stabilized on-site using the ATAD system. (B) Headworks. The headworks consist of a mechanical bar screen, a manual bar rack for back-up, and two vortex-type grit chambers. The maximum rated capacity of the bar screen is 18.0 mgd, and the grit chambers have a combined capacity of 12.0 mgd (16.0 mgd hydraulic capacity). The grit is collected in a partially enclosed container (roll- off box) located undemeath the grit chambers. Ferric chloride (FeCh) is added to the wastewater at a ratio of 2 to 1 (mole iron: mole phosphorus) at the headworks to remove orthophosphorus. (C) Effluent. The effluent from the headworks is split into two flowstreams at the primary distribution box, and conveyed to the primary clarifiers through individual 24- inch pipes. The Facilities have two 80 foot primary clarifiers, each with a 12-foot sidewall depth. The primary sludge is pumped to the sludge holding tank with three (including one stand-by) progressing cavity pumps, each with a rated capacity of 100 gpm. The primary scum is pumped using one progressing cavity pump to the solids holding tank. The stand-by pump for the primary sludge also serves as the stand-by pump for the primary scum. The effluent for the primary clarifiers flows into the aeration distribution box through a 36-inch pipeline, and then is split and conveyed through two individual 30-inch pipes to the activated sludge treatment system. The activated sludge process consists of two aeration basins and two fmal clarifiers. (D) Aeration Hasins. The volume of each aeration basin is approximately 0.926 million gallons at a sidewall depth of 16.2 feet. The design solids retention time ranges between 3.8 and 6.8 days, corresponding to a mixed liquor suspended solids concentration range of 1,500 to 3,000 mgjL. The bottoms of the basins are equipped with a fine-bubble air diffuser system that provide the required air rates up to 8,930 cubic feet per minute at standard conditions. The air to the diffusers is supplied by three 6,000 scfm capacity 1-1